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      1 /*
      2  *  pcap-linux.c: Packet capture interface to the Linux kernel
      3  *
      4  *  Copyright (c) 2000 Torsten Landschoff <torsten (at) debian.org>
      5  *  		       Sebastian Krahmer  <krahmer (at) cs.uni-potsdam.de>
      6  *
      7  *  License: BSD
      8  *
      9  *  Redistribution and use in source and binary forms, with or without
     10  *  modification, are permitted provided that the following conditions
     11  *  are met:
     12  *
     13  *  1. Redistributions of source code must retain the above copyright
     14  *     notice, this list of conditions and the following disclaimer.
     15  *  2. Redistributions in binary form must reproduce the above copyright
     16  *     notice, this list of conditions and the following disclaimer in
     17  *     the documentation and/or other materials provided with the
     18  *     distribution.
     19  *  3. The names of the authors may not be used to endorse or promote
     20  *     products derived from this software without specific prior
     21  *     written permission.
     22  *
     23  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
     24  *  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
     25  *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
     26  *
     27  *  Modifications:     Added PACKET_MMAP support
     28  *                     Paolo Abeni <paolo.abeni (at) email.it>
     29  *                     Added TPACKET_V3 support
     30  *                     Gabor Tatarka <gabor.tatarka (at) ericsson.com>
     31  *
     32  *                     based on previous works of:
     33  *                     Simon Patarin <patarin (at) cs.unibo.it>
     34  *                     Phil Wood <cpw (at) lanl.gov>
     35  *
     36  * Monitor-mode support for mac80211 includes code taken from the iw
     37  * command; the copyright notice for that code is
     38  *
     39  * Copyright (c) 2007, 2008	Johannes Berg
     40  * Copyright (c) 2007		Andy Lutomirski
     41  * Copyright (c) 2007		Mike Kershaw
     42  * Copyright (c) 2008		Gbor Stefanik
     43  *
     44  * All rights reserved.
     45  *
     46  * Redistribution and use in source and binary forms, with or without
     47  * modification, are permitted provided that the following conditions
     48  * are met:
     49  * 1. Redistributions of source code must retain the above copyright
     50  *    notice, this list of conditions and the following disclaimer.
     51  * 2. Redistributions in binary form must reproduce the above copyright
     52  *    notice, this list of conditions and the following disclaimer in the
     53  *    documentation and/or other materials provided with the distribution.
     54  * 3. The name of the author may not be used to endorse or promote products
     55  *    derived from this software without specific prior written permission.
     56  *
     57  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     58  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     59  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     60  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     61  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     62  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     63  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     64  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     65  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     66  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     67  * SUCH DAMAGE.
     68  */
     69 
     70 /*
     71  * Known problems with 2.0[.x] kernels:
     72  *
     73  *   - The loopback device gives every packet twice; on 2.2[.x] kernels,
     74  *     if we use PF_PACKET, we can filter out the transmitted version
     75  *     of the packet by using data in the "sockaddr_ll" returned by
     76  *     "recvfrom()", but, on 2.0[.x] kernels, we have to use
     77  *     PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
     78  *     "sockaddr_pkt" which doesn't give us enough information to let
     79  *     us do that.
     80  *
     81  *   - We have to set the interface's IFF_PROMISC flag ourselves, if
     82  *     we're to run in promiscuous mode, which means we have to turn
     83  *     it off ourselves when we're done; the kernel doesn't keep track
     84  *     of how many sockets are listening promiscuously, which means
     85  *     it won't get turned off automatically when no sockets are
     86  *     listening promiscuously.  We catch "pcap_close()" and, for
     87  *     interfaces we put into promiscuous mode, take them out of
     88  *     promiscuous mode - which isn't necessarily the right thing to
     89  *     do, if another socket also requested promiscuous mode between
     90  *     the time when we opened the socket and the time when we close
     91  *     the socket.
     92  *
     93  *   - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()"
     94  *     return the amount of data that you could have read, rather than
     95  *     the amount that was returned, so we can't just allocate a buffer
     96  *     whose size is the snapshot length and pass the snapshot length
     97  *     as the byte count, and also pass MSG_TRUNC, so that the return
     98  *     value tells us how long the packet was on the wire.
     99  *
    100  *     This means that, if we want to get the actual size of the packet,
    101  *     so we can return it in the "len" field of the packet header,
    102  *     we have to read the entire packet, not just the part that fits
    103  *     within the snapshot length, and thus waste CPU time copying data
    104  *     from the kernel that our caller won't see.
    105  *
    106  *     We have to get the actual size, and supply it in "len", because
    107  *     otherwise, the IP dissector in tcpdump, for example, will complain
    108  *     about "truncated-ip", as the packet will appear to have been
    109  *     shorter, on the wire, than the IP header said it should have been.
    110  */
    111 
    112 
    113 #define _GNU_SOURCE
    114 
    115 #ifdef HAVE_CONFIG_H
    116 #include <config.h>
    117 #endif
    118 
    119 #include <errno.h>
    120 #include <stdio.h>
    121 #include <stdlib.h>
    122 #include <ctype.h>
    123 #include <unistd.h>
    124 #include <fcntl.h>
    125 #include <string.h>
    126 #include <limits.h>
    127 #include <sys/stat.h>
    128 #include <sys/socket.h>
    129 #include <sys/ioctl.h>
    130 #include <sys/utsname.h>
    131 #include <sys/mman.h>
    132 #include <linux/if.h>
    133 #include <linux/if_packet.h>
    134 #include <linux/sockios.h>
    135 #include <netinet/in.h>
    136 #include <linux/if_ether.h>
    137 #include <net/if_arp.h>
    138 #include <poll.h>
    139 #include <dirent.h>
    140 
    141 #include "pcap-int.h"
    142 #include "pcap/sll.h"
    143 #include "pcap/vlan.h"
    144 
    145 /*
    146  * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
    147  * sockets rather than SOCK_PACKET sockets.
    148  *
    149  * To use them, we include <linux/if_packet.h> rather than
    150  * <netpacket/packet.h>; we do so because
    151  *
    152  *	some Linux distributions (e.g., Slackware 4.0) have 2.2 or
    153  *	later kernels and libc5, and don't provide a <netpacket/packet.h>
    154  *	file;
    155  *
    156  *	not all versions of glibc2 have a <netpacket/packet.h> file
    157  *	that defines stuff needed for some of the 2.4-or-later-kernel
    158  *	features, so if the system has a 2.4 or later kernel, we
    159  *	still can't use those features.
    160  *
    161  * We're already including a number of other <linux/XXX.h> headers, and
    162  * this code is Linux-specific (no other OS has PF_PACKET sockets as
    163  * a raw packet capture mechanism), so it's not as if you gain any
    164  * useful portability by using <netpacket/packet.h>
    165  *
    166  * XXX - should we just include <linux/if_packet.h> even if PF_PACKET
    167  * isn't defined?  It only defines one data structure in 2.0.x, so
    168  * it shouldn't cause any problems.
    169  */
    170 #ifdef PF_PACKET
    171 # include <linux/if_packet.h>
    172 
    173  /*
    174   * On at least some Linux distributions (for example, Red Hat 5.2),
    175   * there's no <netpacket/packet.h> file, but PF_PACKET is defined if
    176   * you include <sys/socket.h>, but <linux/if_packet.h> doesn't define
    177   * any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of
    178   * the PACKET_xxx stuff.
    179   *
    180   * So we check whether PACKET_HOST is defined, and assume that we have
    181   * PF_PACKET sockets only if it is defined.
    182   */
    183 # ifdef PACKET_HOST
    184 #  define HAVE_PF_PACKET_SOCKETS
    185 #  ifdef PACKET_AUXDATA
    186 #   define HAVE_PACKET_AUXDATA
    187 #  endif /* PACKET_AUXDATA */
    188 # endif /* PACKET_HOST */
    189 
    190 
    191  /* check for memory mapped access avaibility. We assume every needed
    192   * struct is defined if the macro TPACKET_HDRLEN is defined, because it
    193   * uses many ring related structs and macros */
    194 # ifdef PCAP_SUPPORT_PACKET_RING
    195 # ifdef TPACKET_HDRLEN
    196 #  define HAVE_PACKET_RING
    197 #  ifdef TPACKET3_HDRLEN
    198 #   define HAVE_TPACKET3
    199 #  endif /* TPACKET3_HDRLEN */
    200 #  ifdef TPACKET2_HDRLEN
    201 #   define HAVE_TPACKET2
    202 #  else  /* TPACKET2_HDRLEN */
    203 #   define TPACKET_V1	0    /* Old kernel with only V1, so no TPACKET_Vn defined */
    204 #  endif /* TPACKET2_HDRLEN */
    205 # endif /* TPACKET_HDRLEN */
    206 # endif /* PCAP_SUPPORT_PACKET_RING */
    207 #endif /* PF_PACKET */
    208 
    209 #ifdef SO_ATTACH_FILTER
    210 #include <linux/types.h>
    211 #include <linux/filter.h>
    212 #endif
    213 
    214 #ifdef HAVE_LINUX_NET_TSTAMP_H
    215 #include <linux/net_tstamp.h>
    216 #endif
    217 
    218 #ifdef HAVE_LINUX_SOCKIOS_H
    219 #include <linux/sockios.h>
    220 #endif
    221 
    222 #ifdef HAVE_LINUX_IF_BONDING_H
    223 #include <linux/if_bonding.h>
    224 
    225 /*
    226  * The ioctl code to use to check whether a device is a bonding device.
    227  */
    228 #if defined(SIOCBONDINFOQUERY)
    229 	#define BOND_INFO_QUERY_IOCTL SIOCBONDINFOQUERY
    230 #elif defined(BOND_INFO_QUERY_OLD)
    231 	#define BOND_INFO_QUERY_IOCTL BOND_INFO_QUERY_OLD
    232 #endif
    233 #endif /* HAVE_LINUX_IF_BONDING_H */
    234 
    235 /*
    236  * Got Wireless Extensions?
    237  */
    238 #ifdef HAVE_LINUX_WIRELESS_H
    239 #include <linux/wireless.h>
    240 #endif /* HAVE_LINUX_WIRELESS_H */
    241 
    242 /*
    243  * Got libnl?
    244  */
    245 #ifdef HAVE_LIBNL
    246 #include <linux/nl80211.h>
    247 
    248 #include <netlink/genl/genl.h>
    249 #include <netlink/genl/family.h>
    250 #include <netlink/genl/ctrl.h>
    251 #include <netlink/msg.h>
    252 #include <netlink/attr.h>
    253 #endif /* HAVE_LIBNL */
    254 
    255 /*
    256  * Got ethtool support?
    257  */
    258 #ifdef HAVE_LINUX_ETHTOOL_H
    259 #include <linux/ethtool.h>
    260 #endif
    261 
    262 #ifndef HAVE_SOCKLEN_T
    263 typedef int		socklen_t;
    264 #endif
    265 
    266 #ifndef MSG_TRUNC
    267 /*
    268  * This is being compiled on a system that lacks MSG_TRUNC; define it
    269  * with the value it has in the 2.2 and later kernels, so that, on
    270  * those kernels, when we pass it in the flags argument to "recvfrom()"
    271  * we're passing the right value and thus get the MSG_TRUNC behavior
    272  * we want.  (We don't get that behavior on 2.0[.x] kernels, because
    273  * they didn't support MSG_TRUNC.)
    274  */
    275 #define MSG_TRUNC	0x20
    276 #endif
    277 
    278 #ifndef SOL_PACKET
    279 /*
    280  * This is being compiled on a system that lacks SOL_PACKET; define it
    281  * with the value it has in the 2.2 and later kernels, so that we can
    282  * set promiscuous mode in the good modern way rather than the old
    283  * 2.0-kernel crappy way.
    284  */
    285 #define SOL_PACKET	263
    286 #endif
    287 
    288 #define MAX_LINKHEADER_SIZE	256
    289 
    290 /*
    291  * When capturing on all interfaces we use this as the buffer size.
    292  * Should be bigger then all MTUs that occur in real life.
    293  * 64kB should be enough for now.
    294  */
    295 #define BIGGER_THAN_ALL_MTUS	(64*1024)
    296 
    297 /*
    298  * Private data for capturing on Linux SOCK_PACKET or PF_PACKET sockets.
    299  */
    300 struct pcap_linux {
    301 	u_int	packets_read;	/* count of packets read with recvfrom() */
    302 	long	proc_dropped;	/* packets reported dropped by /proc/net/dev */
    303 	struct pcap_stat stat;
    304 
    305 	char	*device;	/* device name */
    306 	int	filter_in_userland; /* must filter in userland */
    307 	int	blocks_to_filter_in_userland;
    308 	int	must_do_on_close; /* stuff we must do when we close */
    309 	int	timeout;	/* timeout for buffering */
    310 	int	sock_packet;	/* using Linux 2.0 compatible interface */
    311 	int	cooked;		/* using SOCK_DGRAM rather than SOCK_RAW */
    312 	int	ifindex;	/* interface index of device we're bound to */
    313 	int	lo_ifindex;	/* interface index of the loopback device */
    314 	bpf_u_int32 oldmode;	/* mode to restore when turning monitor mode off */
    315 	char	*mondevice;	/* mac80211 monitor device we created */
    316 	u_char	*mmapbuf;	/* memory-mapped region pointer */
    317 	size_t	mmapbuflen;	/* size of region */
    318 	int	vlan_offset;	/* offset at which to insert vlan tags; if -1, don't insert */
    319 	u_int	tp_version;	/* version of tpacket_hdr for mmaped ring */
    320 	u_int	tp_hdrlen;	/* hdrlen of tpacket_hdr for mmaped ring */
    321 	u_char	*oneshot_buffer; /* buffer for copy of packet */
    322 	int	poll_timeout;	/* timeout to use in poll() */
    323 #ifdef HAVE_TPACKET3
    324 	unsigned char *current_packet; /* Current packet within the TPACKET_V3 block. Move to next block if NULL. */
    325 	int packets_left; /* Unhandled packets left within the block from previous call to pcap_read_linux_mmap_v3 in case of TPACKET_V3. */
    326 #endif
    327 };
    328 
    329 /*
    330  * Stuff to do when we close.
    331  */
    332 #define MUST_CLEAR_PROMISC	0x00000001	/* clear promiscuous mode */
    333 #define MUST_CLEAR_RFMON	0x00000002	/* clear rfmon (monitor) mode */
    334 #define MUST_DELETE_MONIF	0x00000004	/* delete monitor-mode interface */
    335 
    336 /*
    337  * Prototypes for internal functions and methods.
    338  */
    339 static int get_if_flags(const char *, bpf_u_int32 *, char *);
    340 static int is_wifi(int, const char *);
    341 static void map_arphrd_to_dlt(pcap_t *, int, int, const char *, int);
    342 #ifdef HAVE_PF_PACKET_SOCKETS
    343 static short int map_packet_type_to_sll_type(short int);
    344 #endif
    345 static int pcap_activate_linux(pcap_t *);
    346 static int activate_old(pcap_t *);
    347 static int activate_new(pcap_t *);
    348 static int activate_mmap(pcap_t *, int *);
    349 static int pcap_can_set_rfmon_linux(pcap_t *);
    350 static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *);
    351 static int pcap_read_packet(pcap_t *, pcap_handler, u_char *);
    352 static int pcap_inject_linux(pcap_t *, const void *, size_t);
    353 static int pcap_stats_linux(pcap_t *, struct pcap_stat *);
    354 static int pcap_setfilter_linux(pcap_t *, struct bpf_program *);
    355 static int pcap_setdirection_linux(pcap_t *, pcap_direction_t);
    356 static int pcap_set_datalink_linux(pcap_t *, int);
    357 static void pcap_cleanup_linux(pcap_t *);
    358 
    359 /*
    360  * This is what the header structure looks like in a 64-bit kernel;
    361  * we use this, rather than struct tpacket_hdr, if we're using
    362  * TPACKET_V1 in 32-bit code running on a 64-bit kernel.
    363  */
    364 struct tpacket_hdr_64 {
    365 	uint64_t	tp_status;
    366 	unsigned int	tp_len;
    367 	unsigned int	tp_snaplen;
    368 	unsigned short	tp_mac;
    369 	unsigned short	tp_net;
    370 	unsigned int	tp_sec;
    371 	unsigned int	tp_usec;
    372 };
    373 
    374 /*
    375  * We use this internally as the tpacket version for TPACKET_V1 in
    376  * 32-bit code on a 64-bit kernel.
    377  */
    378 #define TPACKET_V1_64 99
    379 
    380 union thdr {
    381 	struct tpacket_hdr		*h1;
    382 	struct tpacket_hdr_64		*h1_64;
    383 #ifdef HAVE_TPACKET2
    384 	struct tpacket2_hdr		*h2;
    385 #endif
    386 #ifdef HAVE_TPACKET3
    387 	struct tpacket_block_desc	*h3;
    388 #endif
    389 	void				*raw;
    390 };
    391 
    392 #ifdef HAVE_PACKET_RING
    393 #define RING_GET_FRAME_AT(h, offset) (((union thdr **)h->buffer)[(offset)])
    394 #define RING_GET_CURRENT_FRAME(h) RING_GET_FRAME_AT(h, h->offset)
    395 
    396 static void destroy_ring(pcap_t *handle);
    397 static int create_ring(pcap_t *handle, int *status);
    398 static int prepare_tpacket_socket(pcap_t *handle);
    399 static void pcap_cleanup_linux_mmap(pcap_t *);
    400 static int pcap_read_linux_mmap_v1(pcap_t *, int, pcap_handler , u_char *);
    401 static int pcap_read_linux_mmap_v1_64(pcap_t *, int, pcap_handler , u_char *);
    402 #ifdef HAVE_TPACKET2
    403 static int pcap_read_linux_mmap_v2(pcap_t *, int, pcap_handler , u_char *);
    404 #endif
    405 #ifdef HAVE_TPACKET3
    406 static int pcap_read_linux_mmap_v3(pcap_t *, int, pcap_handler , u_char *);
    407 #endif
    408 static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *);
    409 static int pcap_setnonblock_mmap(pcap_t *p, int nonblock);
    410 static int pcap_getnonblock_mmap(pcap_t *p);
    411 static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
    412     const u_char *bytes);
    413 #endif
    414 
    415 /*
    416  * In pre-3.0 kernels, the tp_vlan_tci field is set to whatever the
    417  * vlan_tci field in the skbuff is.  0 can either mean "not on a VLAN"
    418  * or "on VLAN 0".  There is no flag set in the tp_status field to
    419  * distinguish between them.
    420  *
    421  * In 3.0 and later kernels, if there's a VLAN tag present, the tp_vlan_tci
    422  * field is set to the VLAN tag, and the TP_STATUS_VLAN_VALID flag is set
    423  * in the tp_status field, otherwise the tp_vlan_tci field is set to 0 and
    424  * the TP_STATUS_VLAN_VALID flag isn't set in the tp_status field.
    425  *
    426  * With a pre-3.0 kernel, we cannot distinguish between packets with no
    427  * VLAN tag and packets on VLAN 0, so we will mishandle some packets, and
    428  * there's nothing we can do about that.
    429  *
    430  * So, on those systems, which never set the TP_STATUS_VLAN_VALID flag, we
    431  * continue the behavior of earlier libpcaps, wherein we treated packets
    432  * with a VLAN tag of 0 as being packets without a VLAN tag rather than packets
    433  * on VLAN 0.  We do this by treating packets with a tp_vlan_tci of 0 and
    434  * with the TP_STATUS_VLAN_VALID flag not set in tp_status as not having
    435  * VLAN tags.  This does the right thing on 3.0 and later kernels, and
    436  * continues the old unfixably-imperfect behavior on pre-3.0 kernels.
    437  *
    438  * If TP_STATUS_VLAN_VALID isn't defined, we test it as the 0x10 bit; it
    439  * has that value in 3.0 and later kernels.
    440  */
    441 #ifdef TP_STATUS_VLAN_VALID
    442   #define VLAN_VALID(hdr, hv)	((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & TP_STATUS_VLAN_VALID))
    443 #else
    444   /*
    445    * This is being compiled on a system that lacks TP_STATUS_VLAN_VALID,
    446    * so we testwith the value it has in the 3.0 and later kernels, so
    447    * we can test it if we're running on a system that has it.  (If we're
    448    * running on a system that doesn't have it, it won't be set in the
    449    * tp_status field, so the tests of it will always fail; that means
    450    * we behave the way we did before we introduced this macro.)
    451    */
    452   #define VLAN_VALID(hdr, hv)	((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & 0x10))
    453 #endif
    454 
    455 #ifdef TP_STATUS_VLAN_TPID_VALID
    456 # define VLAN_TPID(hdr, hv)	(((hv)->tp_vlan_tpid || ((hdr)->tp_status & TP_STATUS_VLAN_TPID_VALID)) ? (hv)->tp_vlan_tpid : ETH_P_8021Q)
    457 #else
    458 # define VLAN_TPID(hdr, hv)	ETH_P_8021Q
    459 #endif
    460 
    461 /*
    462  * Wrap some ioctl calls
    463  */
    464 #ifdef HAVE_PF_PACKET_SOCKETS
    465 static int	iface_get_id(int fd, const char *device, char *ebuf);
    466 #endif /* HAVE_PF_PACKET_SOCKETS */
    467 static int	iface_get_mtu(int fd, const char *device, char *ebuf);
    468 static int 	iface_get_arptype(int fd, const char *device, char *ebuf);
    469 #ifdef HAVE_PF_PACKET_SOCKETS
    470 static int 	iface_bind(int fd, int ifindex, char *ebuf, int protocol);
    471 #ifdef IW_MODE_MONITOR
    472 static int	has_wext(int sock_fd, const char *device, char *ebuf);
    473 #endif /* IW_MODE_MONITOR */
    474 static int	enter_rfmon_mode(pcap_t *handle, int sock_fd,
    475     const char *device);
    476 #endif /* HAVE_PF_PACKET_SOCKETS */
    477 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
    478 static int	iface_ethtool_get_ts_info(const char *device, pcap_t *handle,
    479     char *ebuf);
    480 #endif
    481 #ifdef HAVE_PACKET_RING
    482 static int	iface_get_offload(pcap_t *handle);
    483 #endif
    484 static int 	iface_bind_old(int fd, const char *device, char *ebuf);
    485 
    486 #ifdef SO_ATTACH_FILTER
    487 static int	fix_program(pcap_t *handle, struct sock_fprog *fcode,
    488     int is_mapped);
    489 static int	fix_offset(struct bpf_insn *p);
    490 static int	set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode);
    491 static int	reset_kernel_filter(pcap_t *handle);
    492 
    493 static struct sock_filter	total_insn
    494 	= BPF_STMT(BPF_RET | BPF_K, 0);
    495 static struct sock_fprog	total_fcode
    496 	= { 1, &total_insn };
    497 #endif /* SO_ATTACH_FILTER */
    498 
    499 pcap_t *
    500 pcap_create_interface(const char *device, char *ebuf)
    501 {
    502 	pcap_t *handle;
    503 
    504 	handle = pcap_create_common(ebuf, sizeof (struct pcap_linux));
    505 	if (handle == NULL)
    506 		return NULL;
    507 
    508 	handle->activate_op = pcap_activate_linux;
    509 	handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
    510 
    511 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
    512 	/*
    513 	 * See what time stamp types we support.
    514 	 */
    515 	if (iface_ethtool_get_ts_info(device, handle, ebuf) == -1) {
    516 		pcap_close(handle);
    517 		return NULL;
    518 	}
    519 #endif
    520 
    521 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
    522 	/*
    523 	 * We claim that we support microsecond and nanosecond time
    524 	 * stamps.
    525 	 *
    526 	 * XXX - with adapter-supplied time stamps, can we choose
    527 	 * microsecond or nanosecond time stamps on arbitrary
    528 	 * adapters?
    529 	 */
    530 	handle->tstamp_precision_count = 2;
    531 	handle->tstamp_precision_list = malloc(2 * sizeof(u_int));
    532 	if (handle->tstamp_precision_list == NULL) {
    533 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
    534 		    errno, "malloc");
    535 		pcap_close(handle);
    536 		return NULL;
    537 	}
    538 	handle->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
    539 	handle->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
    540 #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
    541 
    542 	return handle;
    543 }
    544 
    545 #ifdef HAVE_LIBNL
    546 /*
    547  * If interface {if} is a mac80211 driver, the file
    548  * /sys/class/net/{if}/phy80211 is a symlink to
    549  * /sys/class/ieee80211/{phydev}, for some {phydev}.
    550  *
    551  * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
    552  * least, has a "wmaster0" device and a "wlan0" device; the
    553  * latter is the one with the IP address.  Both show up in
    554  * "tcpdump -D" output.  Capturing on the wmaster0 device
    555  * captures with 802.11 headers.
    556  *
    557  * airmon-ng searches through /sys/class/net for devices named
    558  * monN, starting with mon0; as soon as one *doesn't* exist,
    559  * it chooses that as the monitor device name.  If the "iw"
    560  * command exists, it does "iw dev {if} interface add {monif}
    561  * type monitor", where {monif} is the monitor device.  It
    562  * then (sigh) sleeps .1 second, and then configures the
    563  * device up.  Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
    564  * is a file, it writes {mondev}, without a newline, to that file,
    565  * and again (sigh) sleeps .1 second, and then iwconfig's that
    566  * device into monitor mode and configures it up.  Otherwise,
    567  * you can't do monitor mode.
    568  *
    569  * All these devices are "glued" together by having the
    570  * /sys/class/net/{device}/phy80211 links pointing to the same
    571  * place, so, given a wmaster, wlan, or mon device, you can
    572  * find the other devices by looking for devices with
    573  * the same phy80211 link.
    574  *
    575  * To turn monitor mode off, delete the monitor interface,
    576  * either with "iw dev {monif} interface del" or by sending
    577  * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
    578  *
    579  * Note: if you try to create a monitor device named "monN", and
    580  * there's already a "monN" device, it fails, as least with
    581  * the netlink interface (which is what iw uses), with a return
    582  * value of -ENFILE.  (Return values are negative errnos.)  We
    583  * could probably use that to find an unused device.
    584  *
    585  * Yes, you can have multiple monitor devices for a given
    586  * physical device.
    587  */
    588 
    589 /*
    590  * Is this a mac80211 device?  If so, fill in the physical device path and
    591  * return 1; if not, return 0.  On an error, fill in handle->errbuf and
    592  * return PCAP_ERROR.
    593  */
    594 static int
    595 get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
    596     size_t phydev_max_pathlen)
    597 {
    598 	char *pathstr;
    599 	ssize_t bytes_read;
    600 
    601 	/*
    602 	 * Generate the path string for the symlink to the physical device.
    603 	 */
    604 	if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) {
    605 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    606 		    "%s: Can't generate path name string for /sys/class/net device",
    607 		    device);
    608 		return PCAP_ERROR;
    609 	}
    610 	bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen);
    611 	if (bytes_read == -1) {
    612 		if (errno == ENOENT || errno == EINVAL) {
    613 			/*
    614 			 * Doesn't exist, or not a symlink; assume that
    615 			 * means it's not a mac80211 device.
    616 			 */
    617 			free(pathstr);
    618 			return 0;
    619 		}
    620 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
    621 		    errno, "%s: Can't readlink %s", device, pathstr);
    622 		free(pathstr);
    623 		return PCAP_ERROR;
    624 	}
    625 	free(pathstr);
    626 	phydev_path[bytes_read] = '\0';
    627 	return 1;
    628 }
    629 
    630 #ifdef HAVE_LIBNL_SOCKETS
    631 #define get_nl_errmsg	nl_geterror
    632 #else
    633 /* libnl 2.x compatibility code */
    634 
    635 #define nl_sock nl_handle
    636 
    637 static inline struct nl_handle *
    638 nl_socket_alloc(void)
    639 {
    640 	return nl_handle_alloc();
    641 }
    642 
    643 static inline void
    644 nl_socket_free(struct nl_handle *h)
    645 {
    646 	nl_handle_destroy(h);
    647 }
    648 
    649 #define get_nl_errmsg	strerror
    650 
    651 static inline int
    652 __genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache)
    653 {
    654 	struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
    655 	if (!tmp)
    656 		return -ENOMEM;
    657 	*cache = tmp;
    658 	return 0;
    659 }
    660 #define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
    661 #endif /* !HAVE_LIBNL_SOCKETS */
    662 
    663 struct nl80211_state {
    664 	struct nl_sock *nl_sock;
    665 	struct nl_cache *nl_cache;
    666 	struct genl_family *nl80211;
    667 };
    668 
    669 static int
    670 nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
    671 {
    672 	int err;
    673 
    674 	state->nl_sock = nl_socket_alloc();
    675 	if (!state->nl_sock) {
    676 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    677 		    "%s: failed to allocate netlink handle", device);
    678 		return PCAP_ERROR;
    679 	}
    680 
    681 	if (genl_connect(state->nl_sock)) {
    682 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    683 		    "%s: failed to connect to generic netlink", device);
    684 		goto out_handle_destroy;
    685 	}
    686 
    687 	err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
    688 	if (err < 0) {
    689 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    690 		    "%s: failed to allocate generic netlink cache: %s",
    691 		    device, get_nl_errmsg(-err));
    692 		goto out_handle_destroy;
    693 	}
    694 
    695 	state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
    696 	if (!state->nl80211) {
    697 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    698 		    "%s: nl80211 not found", device);
    699 		goto out_cache_free;
    700 	}
    701 
    702 	return 0;
    703 
    704 out_cache_free:
    705 	nl_cache_free(state->nl_cache);
    706 out_handle_destroy:
    707 	nl_socket_free(state->nl_sock);
    708 	return PCAP_ERROR;
    709 }
    710 
    711 static void
    712 nl80211_cleanup(struct nl80211_state *state)
    713 {
    714 	genl_family_put(state->nl80211);
    715 	nl_cache_free(state->nl_cache);
    716 	nl_socket_free(state->nl_sock);
    717 }
    718 
    719 static int
    720 del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
    721     const char *device, const char *mondevice);
    722 
    723 static int
    724 add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
    725     const char *device, const char *mondevice)
    726 {
    727 	struct pcap_linux *handlep = handle->priv;
    728 	int ifindex;
    729 	struct nl_msg *msg;
    730 	int err;
    731 
    732 	ifindex = iface_get_id(sock_fd, device, handle->errbuf);
    733 	if (ifindex == -1)
    734 		return PCAP_ERROR;
    735 
    736 	msg = nlmsg_alloc();
    737 	if (!msg) {
    738 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    739 		    "%s: failed to allocate netlink msg", device);
    740 		return PCAP_ERROR;
    741 	}
    742 
    743 	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
    744 		    0, NL80211_CMD_NEW_INTERFACE, 0);
    745 	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
    746 	NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
    747 	NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
    748 
    749 	err = nl_send_auto_complete(state->nl_sock, msg);
    750 	if (err < 0) {
    751 #if defined HAVE_LIBNL_NLE
    752 		if (err == -NLE_FAILURE) {
    753 #else
    754 		if (err == -ENFILE) {
    755 #endif
    756 			/*
    757 			 * Device not available; our caller should just
    758 			 * keep trying.  (libnl 2.x maps ENFILE to
    759 			 * NLE_FAILURE; it can also map other errors
    760 			 * to that, but there's not much we can do
    761 			 * about that.)
    762 			 */
    763 			nlmsg_free(msg);
    764 			return 0;
    765 		} else {
    766 			/*
    767 			 * Real failure, not just "that device is not
    768 			 * available.
    769 			 */
    770 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    771 			    "%s: nl_send_auto_complete failed adding %s interface: %s",
    772 			    device, mondevice, get_nl_errmsg(-err));
    773 			nlmsg_free(msg);
    774 			return PCAP_ERROR;
    775 		}
    776 	}
    777 	err = nl_wait_for_ack(state->nl_sock);
    778 	if (err < 0) {
    779 #if defined HAVE_LIBNL_NLE
    780 		if (err == -NLE_FAILURE) {
    781 #else
    782 		if (err == -ENFILE) {
    783 #endif
    784 			/*
    785 			 * Device not available; our caller should just
    786 			 * keep trying.  (libnl 2.x maps ENFILE to
    787 			 * NLE_FAILURE; it can also map other errors
    788 			 * to that, but there's not much we can do
    789 			 * about that.)
    790 			 */
    791 			nlmsg_free(msg);
    792 			return 0;
    793 		} else {
    794 			/*
    795 			 * Real failure, not just "that device is not
    796 			 * available.
    797 			 */
    798 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    799 			    "%s: nl_wait_for_ack failed adding %s interface: %s",
    800 			    device, mondevice, get_nl_errmsg(-err));
    801 			nlmsg_free(msg);
    802 			return PCAP_ERROR;
    803 		}
    804 	}
    805 
    806 	/*
    807 	 * Success.
    808 	 */
    809 	nlmsg_free(msg);
    810 
    811 	/*
    812 	 * Try to remember the monitor device.
    813 	 */
    814 	handlep->mondevice = strdup(mondevice);
    815 	if (handlep->mondevice == NULL) {
    816 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
    817 		    errno, "strdup");
    818 		/*
    819 		 * Get rid of the monitor device.
    820 		 */
    821 		del_mon_if(handle, sock_fd, state, device, mondevice);
    822 		return PCAP_ERROR;
    823 	}
    824 	return 1;
    825 
    826 nla_put_failure:
    827 	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    828 	    "%s: nl_put failed adding %s interface",
    829 	    device, mondevice);
    830 	nlmsg_free(msg);
    831 	return PCAP_ERROR;
    832 }
    833 
    834 static int
    835 del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
    836     const char *device, const char *mondevice)
    837 {
    838 	int ifindex;
    839 	struct nl_msg *msg;
    840 	int err;
    841 
    842 	ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf);
    843 	if (ifindex == -1)
    844 		return PCAP_ERROR;
    845 
    846 	msg = nlmsg_alloc();
    847 	if (!msg) {
    848 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    849 		    "%s: failed to allocate netlink msg", device);
    850 		return PCAP_ERROR;
    851 	}
    852 
    853 	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
    854 		    0, NL80211_CMD_DEL_INTERFACE, 0);
    855 	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
    856 
    857 	err = nl_send_auto_complete(state->nl_sock, msg);
    858 	if (err < 0) {
    859 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    860 		    "%s: nl_send_auto_complete failed deleting %s interface: %s",
    861 		    device, mondevice, get_nl_errmsg(-err));
    862 		nlmsg_free(msg);
    863 		return PCAP_ERROR;
    864 	}
    865 	err = nl_wait_for_ack(state->nl_sock);
    866 	if (err < 0) {
    867 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    868 		    "%s: nl_wait_for_ack failed adding %s interface: %s",
    869 		    device, mondevice, get_nl_errmsg(-err));
    870 		nlmsg_free(msg);
    871 		return PCAP_ERROR;
    872 	}
    873 
    874 	/*
    875 	 * Success.
    876 	 */
    877 	nlmsg_free(msg);
    878 	return 1;
    879 
    880 nla_put_failure:
    881 	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    882 	    "%s: nl_put failed deleting %s interface",
    883 	    device, mondevice);
    884 	nlmsg_free(msg);
    885 	return PCAP_ERROR;
    886 }
    887 
    888 static int
    889 enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
    890 {
    891 	struct pcap_linux *handlep = handle->priv;
    892 	int ret;
    893 	char phydev_path[PATH_MAX+1];
    894 	struct nl80211_state nlstate;
    895 	struct ifreq ifr;
    896 	u_int n;
    897 
    898 	/*
    899 	 * Is this a mac80211 device?
    900 	 */
    901 	ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX);
    902 	if (ret < 0)
    903 		return ret;	/* error */
    904 	if (ret == 0)
    905 		return 0;	/* no error, but not mac80211 device */
    906 
    907 	/*
    908 	 * XXX - is this already a monN device?
    909 	 * If so, we're done.
    910 	 * Is that determined by old Wireless Extensions ioctls?
    911 	 */
    912 
    913 	/*
    914 	 * OK, it's apparently a mac80211 device.
    915 	 * Try to find an unused monN device for it.
    916 	 */
    917 	ret = nl80211_init(handle, &nlstate, device);
    918 	if (ret != 0)
    919 		return ret;
    920 	for (n = 0; n < UINT_MAX; n++) {
    921 		/*
    922 		 * Try mon{n}.
    923 		 */
    924 		char mondevice[3+10+1];	/* mon{UINT_MAX}\0 */
    925 
    926 		pcap_snprintf(mondevice, sizeof mondevice, "mon%u", n);
    927 		ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice);
    928 		if (ret == 1) {
    929 			/*
    930 			 * Success.  We don't clean up the libnl state
    931 			 * yet, as we'll be using it later.
    932 			 */
    933 			goto added;
    934 		}
    935 		if (ret < 0) {
    936 			/*
    937 			 * Hard failure.  Just return ret; handle->errbuf
    938 			 * has already been set.
    939 			 */
    940 			nl80211_cleanup(&nlstate);
    941 			return ret;
    942 		}
    943 	}
    944 
    945 	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
    946 	    "%s: No free monN interfaces", device);
    947 	nl80211_cleanup(&nlstate);
    948 	return PCAP_ERROR;
    949 
    950 added:
    951 
    952 #if 0
    953 	/*
    954 	 * Sleep for .1 seconds.
    955 	 */
    956 	delay.tv_sec = 0;
    957 	delay.tv_nsec = 500000000;
    958 	nanosleep(&delay, NULL);
    959 #endif
    960 
    961 	/*
    962 	 * If we haven't already done so, arrange to have
    963 	 * "pcap_close_all()" called when we exit.
    964 	 */
    965 	if (!pcap_do_addexit(handle)) {
    966 		/*
    967 		 * "atexit()" failed; don't put the interface
    968 		 * in rfmon mode, just give up.
    969 		 */
    970 		del_mon_if(handle, sock_fd, &nlstate, device,
    971 		    handlep->mondevice);
    972 		nl80211_cleanup(&nlstate);
    973 		return PCAP_ERROR;
    974 	}
    975 
    976 	/*
    977 	 * Now configure the monitor interface up.
    978 	 */
    979 	memset(&ifr, 0, sizeof(ifr));
    980 	strlcpy(ifr.ifr_name, handlep->mondevice, sizeof(ifr.ifr_name));
    981 	if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
    982 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
    983 		    errno, "%s: Can't get flags for %s", device,
    984 		    handlep->mondevice);
    985 		del_mon_if(handle, sock_fd, &nlstate, device,
    986 		    handlep->mondevice);
    987 		nl80211_cleanup(&nlstate);
    988 		return PCAP_ERROR;
    989 	}
    990 	ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
    991 	if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
    992 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
    993 		    errno, "%s: Can't set flags for %s", device,
    994 		    handlep->mondevice);
    995 		del_mon_if(handle, sock_fd, &nlstate, device,
    996 		    handlep->mondevice);
    997 		nl80211_cleanup(&nlstate);
    998 		return PCAP_ERROR;
    999 	}
   1000 
   1001 	/*
   1002 	 * Success.  Clean up the libnl state.
   1003 	 */
   1004 	nl80211_cleanup(&nlstate);
   1005 
   1006 	/*
   1007 	 * Note that we have to delete the monitor device when we close
   1008 	 * the handle.
   1009 	 */
   1010 	handlep->must_do_on_close |= MUST_DELETE_MONIF;
   1011 
   1012 	/*
   1013 	 * Add this to the list of pcaps to close when we exit.
   1014 	 */
   1015 	pcap_add_to_pcaps_to_close(handle);
   1016 
   1017 	return 1;
   1018 }
   1019 #endif /* HAVE_LIBNL */
   1020 
   1021 #ifdef IW_MODE_MONITOR
   1022 /*
   1023  * Bonding devices mishandle unknown ioctls; they fail with ENODEV
   1024  * rather than ENOTSUP, EOPNOTSUPP, or ENOTTY, so Wireless Extensions
   1025  * will fail with ENODEV if we try to do them on a bonding device,
   1026  * making us return a "no such device" indication rather than just
   1027  * saying "no Wireless Extensions".
   1028  *
   1029  * So we check for bonding devices, if we can, before trying those
   1030  * ioctls, by trying a bonding device information query ioctl to see
   1031  * whether it succeeds.
   1032  */
   1033 static int
   1034 is_bonding_device(int fd, const char *device)
   1035 {
   1036 #ifdef BOND_INFO_QUERY_IOCTL
   1037 	struct ifreq ifr;
   1038 	ifbond ifb;
   1039 
   1040 	memset(&ifr, 0, sizeof ifr);
   1041 	strlcpy(ifr.ifr_name, device, sizeof ifr.ifr_name);
   1042 	memset(&ifb, 0, sizeof ifb);
   1043 	ifr.ifr_data = (caddr_t)&ifb;
   1044 	if (ioctl(fd, BOND_INFO_QUERY_IOCTL, &ifr) == 0)
   1045 		return 1;	/* success, so it's a bonding device */
   1046 #endif /* BOND_INFO_QUERY_IOCTL */
   1047 
   1048 	return 0;	/* no, it's not a bonding device */
   1049 }
   1050 #endif /* IW_MODE_MONITOR */
   1051 
   1052 static int pcap_protocol(pcap_t *handle)
   1053 {
   1054 	int protocol;
   1055 
   1056 	protocol = handle->opt.protocol;
   1057 	if (protocol == 0)
   1058 		protocol = ETH_P_ALL;
   1059 
   1060 	return htons(protocol);
   1061 }
   1062 
   1063 static int
   1064 pcap_can_set_rfmon_linux(pcap_t *handle)
   1065 {
   1066 #ifdef HAVE_LIBNL
   1067 	char phydev_path[PATH_MAX+1];
   1068 	int ret;
   1069 #endif
   1070 #ifdef IW_MODE_MONITOR
   1071 	int sock_fd;
   1072 	struct iwreq ireq;
   1073 #endif
   1074 
   1075 	if (strcmp(handle->opt.device, "any") == 0) {
   1076 		/*
   1077 		 * Monitor mode makes no sense on the "any" device.
   1078 		 */
   1079 		return 0;
   1080 	}
   1081 
   1082 #ifdef HAVE_LIBNL
   1083 	/*
   1084 	 * Bleah.  There doesn't seem to be a way to ask a mac80211
   1085 	 * device, through libnl, whether it supports monitor mode;
   1086 	 * we'll just check whether the device appears to be a
   1087 	 * mac80211 device and, if so, assume the device supports
   1088 	 * monitor mode.
   1089 	 *
   1090 	 * wmaster devices don't appear to support the Wireless
   1091 	 * Extensions, but we can create a mon device for a
   1092 	 * wmaster device, so we don't bother checking whether
   1093 	 * a mac80211 device supports the Wireless Extensions.
   1094 	 */
   1095 	ret = get_mac80211_phydev(handle, handle->opt.device, phydev_path,
   1096 	    PATH_MAX);
   1097 	if (ret < 0)
   1098 		return ret;	/* error */
   1099 	if (ret == 1)
   1100 		return 1;	/* mac80211 device */
   1101 #endif
   1102 
   1103 #ifdef IW_MODE_MONITOR
   1104 	/*
   1105 	 * Bleah.  There doesn't appear to be an ioctl to use to ask
   1106 	 * whether a device supports monitor mode; we'll just do
   1107 	 * SIOCGIWMODE and, if it succeeds, assume the device supports
   1108 	 * monitor mode.
   1109 	 *
   1110 	 * Open a socket on which to attempt to get the mode.
   1111 	 * (We assume that if we have Wireless Extensions support
   1112 	 * we also have PF_PACKET support.)
   1113 	 */
   1114 	sock_fd = socket(PF_PACKET, SOCK_RAW, pcap_protocol(handle));
   1115 	if (sock_fd == -1) {
   1116 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   1117 		    errno, "socket");
   1118 		return PCAP_ERROR;
   1119 	}
   1120 
   1121 	if (is_bonding_device(sock_fd, handle->opt.device)) {
   1122 		/* It's a bonding device, so don't even try. */
   1123 		close(sock_fd);
   1124 		return 0;
   1125 	}
   1126 
   1127 	/*
   1128 	 * Attempt to get the current mode.
   1129 	 */
   1130 	strlcpy(ireq.ifr_ifrn.ifrn_name, handle->opt.device,
   1131 	    sizeof ireq.ifr_ifrn.ifrn_name);
   1132 	if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) {
   1133 		/*
   1134 		 * Well, we got the mode; assume we can set it.
   1135 		 */
   1136 		close(sock_fd);
   1137 		return 1;
   1138 	}
   1139 	if (errno == ENODEV) {
   1140 		/* The device doesn't even exist. */
   1141 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   1142 		    errno, "SIOCGIWMODE failed");
   1143 		close(sock_fd);
   1144 		return PCAP_ERROR_NO_SUCH_DEVICE;
   1145 	}
   1146 	close(sock_fd);
   1147 #endif
   1148 	return 0;
   1149 }
   1150 
   1151 /*
   1152  * Grabs the number of dropped packets by the interface from /proc/net/dev.
   1153  *
   1154  * XXX - what about /sys/class/net/{interface name}/rx_*?  There are
   1155  * individual devices giving, in ASCII, various rx_ and tx_ statistics.
   1156  *
   1157  * Or can we get them in binary form from netlink?
   1158  */
   1159 static long int
   1160 linux_if_drops(const char * if_name)
   1161 {
   1162 	char buffer[512];
   1163 	char * bufptr;
   1164 	FILE * file;
   1165 	int field_to_convert = 3, if_name_sz = strlen(if_name);
   1166 	long int dropped_pkts = 0;
   1167 
   1168 	file = fopen("/proc/net/dev", "r");
   1169 	if (!file)
   1170 		return 0;
   1171 
   1172 	while (!dropped_pkts && fgets( buffer, sizeof(buffer), file ))
   1173 	{
   1174 		/* 	search for 'bytes' -- if its in there, then
   1175 			that means we need to grab the fourth field. otherwise
   1176 			grab the third field. */
   1177 		if (field_to_convert != 4 && strstr(buffer, "bytes"))
   1178 		{
   1179 			field_to_convert = 4;
   1180 			continue;
   1181 		}
   1182 
   1183 		/* find iface and make sure it actually matches -- space before the name and : after it */
   1184 		if ((bufptr = strstr(buffer, if_name)) &&
   1185 			(bufptr == buffer || *(bufptr-1) == ' ') &&
   1186 			*(bufptr + if_name_sz) == ':')
   1187 		{
   1188 			bufptr = bufptr + if_name_sz + 1;
   1189 
   1190 			/* grab the nth field from it */
   1191 			while( --field_to_convert && *bufptr != '\0')
   1192 			{
   1193 				while (*bufptr != '\0' && *(bufptr++) == ' ');
   1194 				while (*bufptr != '\0' && *(bufptr++) != ' ');
   1195 			}
   1196 
   1197 			/* get rid of any final spaces */
   1198 			while (*bufptr != '\0' && *bufptr == ' ') bufptr++;
   1199 
   1200 			if (*bufptr != '\0')
   1201 				dropped_pkts = strtol(bufptr, NULL, 10);
   1202 
   1203 			break;
   1204 		}
   1205 	}
   1206 
   1207 	fclose(file);
   1208 	return dropped_pkts;
   1209 }
   1210 
   1211 
   1212 /*
   1213  * With older kernels promiscuous mode is kind of interesting because we
   1214  * have to reset the interface before exiting. The problem can't really
   1215  * be solved without some daemon taking care of managing usage counts.
   1216  * If we put the interface into promiscuous mode, we set a flag indicating
   1217  * that we must take it out of that mode when the interface is closed,
   1218  * and, when closing the interface, if that flag is set we take it out
   1219  * of promiscuous mode.
   1220  *
   1221  * Even with newer kernels, we have the same issue with rfmon mode.
   1222  */
   1223 
   1224 static void	pcap_cleanup_linux( pcap_t *handle )
   1225 {
   1226 	struct pcap_linux *handlep = handle->priv;
   1227 	struct ifreq	ifr;
   1228 #ifdef HAVE_LIBNL
   1229 	struct nl80211_state nlstate;
   1230 	int ret;
   1231 #endif /* HAVE_LIBNL */
   1232 #ifdef IW_MODE_MONITOR
   1233 	int oldflags;
   1234 	struct iwreq ireq;
   1235 #endif /* IW_MODE_MONITOR */
   1236 
   1237 	if (handlep->must_do_on_close != 0) {
   1238 		/*
   1239 		 * There's something we have to do when closing this
   1240 		 * pcap_t.
   1241 		 */
   1242 		if (handlep->must_do_on_close & MUST_CLEAR_PROMISC) {
   1243 			/*
   1244 			 * We put the interface into promiscuous mode;
   1245 			 * take it out of promiscuous mode.
   1246 			 *
   1247 			 * XXX - if somebody else wants it in promiscuous
   1248 			 * mode, this code cannot know that, so it'll take
   1249 			 * it out of promiscuous mode.  That's not fixable
   1250 			 * in 2.0[.x] kernels.
   1251 			 */
   1252 			memset(&ifr, 0, sizeof(ifr));
   1253 			strlcpy(ifr.ifr_name, handlep->device,
   1254 			    sizeof(ifr.ifr_name));
   1255 			if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
   1256 				fprintf(stderr,
   1257 				    "Can't restore interface %s flags (SIOCGIFFLAGS failed: %s).\n"
   1258 				    "Please adjust manually.\n"
   1259 				    "Hint: This can't happen with Linux >= 2.2.0.\n",
   1260 				    handlep->device, strerror(errno));
   1261 			} else {
   1262 				if (ifr.ifr_flags & IFF_PROMISC) {
   1263 					/*
   1264 					 * Promiscuous mode is currently on;
   1265 					 * turn it off.
   1266 					 */
   1267 					ifr.ifr_flags &= ~IFF_PROMISC;
   1268 					if (ioctl(handle->fd, SIOCSIFFLAGS,
   1269 					    &ifr) == -1) {
   1270 						fprintf(stderr,
   1271 						    "Can't restore interface %s flags (SIOCSIFFLAGS failed: %s).\n"
   1272 						    "Please adjust manually.\n"
   1273 						    "Hint: This can't happen with Linux >= 2.2.0.\n",
   1274 						    handlep->device,
   1275 						    strerror(errno));
   1276 					}
   1277 				}
   1278 			}
   1279 		}
   1280 
   1281 #ifdef HAVE_LIBNL
   1282 		if (handlep->must_do_on_close & MUST_DELETE_MONIF) {
   1283 			ret = nl80211_init(handle, &nlstate, handlep->device);
   1284 			if (ret >= 0) {
   1285 				ret = del_mon_if(handle, handle->fd, &nlstate,
   1286 				    handlep->device, handlep->mondevice);
   1287 				nl80211_cleanup(&nlstate);
   1288 			}
   1289 			if (ret < 0) {
   1290 				fprintf(stderr,
   1291 				    "Can't delete monitor interface %s (%s).\n"
   1292 				    "Please delete manually.\n",
   1293 				    handlep->mondevice, handle->errbuf);
   1294 			}
   1295 		}
   1296 #endif /* HAVE_LIBNL */
   1297 
   1298 #ifdef IW_MODE_MONITOR
   1299 		if (handlep->must_do_on_close & MUST_CLEAR_RFMON) {
   1300 			/*
   1301 			 * We put the interface into rfmon mode;
   1302 			 * take it out of rfmon mode.
   1303 			 *
   1304 			 * XXX - if somebody else wants it in rfmon
   1305 			 * mode, this code cannot know that, so it'll take
   1306 			 * it out of rfmon mode.
   1307 			 */
   1308 
   1309 			/*
   1310 			 * First, take the interface down if it's up;
   1311 			 * otherwise, we might get EBUSY.
   1312 			 * If we get errors, just drive on and print
   1313 			 * a warning if we can't restore the mode.
   1314 			 */
   1315 			oldflags = 0;
   1316 			memset(&ifr, 0, sizeof(ifr));
   1317 			strlcpy(ifr.ifr_name, handlep->device,
   1318 			    sizeof(ifr.ifr_name));
   1319 			if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) != -1) {
   1320 				if (ifr.ifr_flags & IFF_UP) {
   1321 					oldflags = ifr.ifr_flags;
   1322 					ifr.ifr_flags &= ~IFF_UP;
   1323 					if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1)
   1324 						oldflags = 0;	/* didn't set, don't restore */
   1325 				}
   1326 			}
   1327 
   1328 			/*
   1329 			 * Now restore the mode.
   1330 			 */
   1331 			strlcpy(ireq.ifr_ifrn.ifrn_name, handlep->device,
   1332 			    sizeof ireq.ifr_ifrn.ifrn_name);
   1333 			ireq.u.mode = handlep->oldmode;
   1334 			if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
   1335 				/*
   1336 				 * Scientist, you've failed.
   1337 				 */
   1338 				fprintf(stderr,
   1339 				    "Can't restore interface %s wireless mode (SIOCSIWMODE failed: %s).\n"
   1340 				    "Please adjust manually.\n",
   1341 				    handlep->device, strerror(errno));
   1342 			}
   1343 
   1344 			/*
   1345 			 * Now bring the interface back up if we brought
   1346 			 * it down.
   1347 			 */
   1348 			if (oldflags != 0) {
   1349 				ifr.ifr_flags = oldflags;
   1350 				if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
   1351 					fprintf(stderr,
   1352 					    "Can't bring interface %s back up (SIOCSIFFLAGS failed: %s).\n"
   1353 					    "Please adjust manually.\n",
   1354 					    handlep->device, strerror(errno));
   1355 				}
   1356 			}
   1357 		}
   1358 #endif /* IW_MODE_MONITOR */
   1359 
   1360 		/*
   1361 		 * Take this pcap out of the list of pcaps for which we
   1362 		 * have to take the interface out of some mode.
   1363 		 */
   1364 		pcap_remove_from_pcaps_to_close(handle);
   1365 	}
   1366 
   1367 	if (handlep->mondevice != NULL) {
   1368 		free(handlep->mondevice);
   1369 		handlep->mondevice = NULL;
   1370 	}
   1371 	if (handlep->device != NULL) {
   1372 		free(handlep->device);
   1373 		handlep->device = NULL;
   1374 	}
   1375 	pcap_cleanup_live_common(handle);
   1376 }
   1377 
   1378 /*
   1379  * Set the timeout to be used in poll() with memory-mapped packet capture.
   1380  */
   1381 static void
   1382 set_poll_timeout(struct pcap_linux *handlep)
   1383 {
   1384 #ifdef HAVE_TPACKET3
   1385 	struct utsname utsname;
   1386 	char *version_component, *endp;
   1387 	int major, minor;
   1388 	int broken_tpacket_v3 = 1;
   1389 
   1390 	/*
   1391 	 * Some versions of TPACKET_V3 have annoying bugs/misfeatures
   1392 	 * around which we have to work.  Determine if we have those
   1393 	 * problems or not.
   1394 	 */
   1395 	if (uname(&utsname) == 0) {
   1396 		/*
   1397 		 * 3.19 is the first release with a fixed version of
   1398 		 * TPACKET_V3.  We treat anything before that as
   1399 		 * not haveing a fixed version; that may really mean
   1400 		 * it has *no* version.
   1401 		 */
   1402 		version_component = utsname.release;
   1403 		major = strtol(version_component, &endp, 10);
   1404 		if (endp != version_component && *endp == '.') {
   1405 			/*
   1406 			 * OK, that was a valid major version.
   1407 			 * Get the minor version.
   1408 			 */
   1409 			version_component = endp + 1;
   1410 			minor = strtol(version_component, &endp, 10);
   1411 			if (endp != version_component &&
   1412 			    (*endp == '.' || *endp == '\0')) {
   1413 				/*
   1414 				 * OK, that was a valid minor version.
   1415 				 * Is this 3.19 or newer?
   1416 				 */
   1417 				if (major >= 4 || (major == 3 && minor >= 19)) {
   1418 					/* Yes. TPACKET_V3 works correctly. */
   1419 					broken_tpacket_v3 = 0;
   1420 				}
   1421 			}
   1422 		}
   1423 	}
   1424 #endif
   1425 	if (handlep->timeout == 0) {
   1426 #ifdef HAVE_TPACKET3
   1427 		/*
   1428 		 * XXX - due to a set of (mis)features in the TPACKET_V3
   1429 		 * kernel code prior to the 3.19 kernel, blocking forever
   1430 		 * with a TPACKET_V3 socket can, if few packets are
   1431 		 * arriving and passing the socket filter, cause most
   1432 		 * packets to be dropped.  See libpcap issue #335 for the
   1433 		 * full painful story.
   1434 		 *
   1435 		 * The workaround is to have poll() time out very quickly,
   1436 		 * so we grab the frames handed to us, and return them to
   1437 		 * the kernel, ASAP.
   1438 		 */
   1439 		if (handlep->tp_version == TPACKET_V3 && broken_tpacket_v3)
   1440 			handlep->poll_timeout = 1;	/* don't block for very long */
   1441 		else
   1442 #endif
   1443 			handlep->poll_timeout = -1;	/* block forever */
   1444 	} else if (handlep->timeout > 0) {
   1445 #ifdef HAVE_TPACKET3
   1446 		/*
   1447 		 * For TPACKET_V3, the timeout is handled by the kernel,
   1448 		 * so block forever; that way, we don't get extra timeouts.
   1449 		 * Don't do that if we have a broken TPACKET_V3, though.
   1450 		 */
   1451 		if (handlep->tp_version == TPACKET_V3 && !broken_tpacket_v3)
   1452 			handlep->poll_timeout = -1;	/* block forever, let TPACKET_V3 wake us up */
   1453 		else
   1454 #endif
   1455 			handlep->poll_timeout = handlep->timeout;	/* block for that amount of time */
   1456 	} else {
   1457 		/*
   1458 		 * Non-blocking mode; we call poll() to pick up error
   1459 		 * indications, but we don't want it to wait for
   1460 		 * anything.
   1461 		 */
   1462 		handlep->poll_timeout = 0;
   1463 	}
   1464 }
   1465 
   1466 /*
   1467  *  Get a handle for a live capture from the given device. You can
   1468  *  pass NULL as device to get all packages (without link level
   1469  *  information of course). If you pass 1 as promisc the interface
   1470  *  will be set to promiscous mode (XXX: I think this usage should
   1471  *  be deprecated and functions be added to select that later allow
   1472  *  modification of that values -- Torsten).
   1473  */
   1474 static int
   1475 pcap_activate_linux(pcap_t *handle)
   1476 {
   1477 	struct pcap_linux *handlep = handle->priv;
   1478 	const char	*device;
   1479 	struct ifreq	ifr;
   1480 	int		status = 0;
   1481 	int		ret;
   1482 
   1483 	device = handle->opt.device;
   1484 
   1485 	/*
   1486 	 * Make sure the name we were handed will fit into the ioctls we
   1487 	 * might perform on the device; if not, return a "No such device"
   1488 	 * indication, as the Linux kernel shouldn't support creating
   1489 	 * a device whose name won't fit into those ioctls.
   1490 	 *
   1491 	 * "Will fit" means "will fit, complete with a null terminator",
   1492 	 * so if the length, which does *not* include the null terminator,
   1493 	 * is greater than *or equal to* the size of the field into which
   1494 	 * we'll be copying it, that won't fit.
   1495 	 */
   1496 	if (strlen(device) >= sizeof(ifr.ifr_name)) {
   1497 		status = PCAP_ERROR_NO_SUCH_DEVICE;
   1498 		goto fail;
   1499 	}
   1500 
   1501 	/*
   1502 	 * Turn a negative snapshot value (invalid), a snapshot value of
   1503 	 * 0 (unspecified), or a value bigger than the normal maximum
   1504 	 * value, into the maximum allowed value.
   1505 	 *
   1506 	 * If some application really *needs* a bigger snapshot
   1507 	 * length, we should just increase MAXIMUM_SNAPLEN.
   1508 	 */
   1509 	if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
   1510 		handle->snapshot = MAXIMUM_SNAPLEN;
   1511 
   1512 	handle->inject_op = pcap_inject_linux;
   1513 	handle->setfilter_op = pcap_setfilter_linux;
   1514 	handle->setdirection_op = pcap_setdirection_linux;
   1515 	handle->set_datalink_op = pcap_set_datalink_linux;
   1516 	handle->getnonblock_op = pcap_getnonblock_fd;
   1517 	handle->setnonblock_op = pcap_setnonblock_fd;
   1518 	handle->cleanup_op = pcap_cleanup_linux;
   1519 	handle->read_op = pcap_read_linux;
   1520 	handle->stats_op = pcap_stats_linux;
   1521 
   1522 	/*
   1523 	 * The "any" device is a special device which causes us not
   1524 	 * to bind to a particular device and thus to look at all
   1525 	 * devices.
   1526 	 */
   1527 	if (strcmp(device, "any") == 0) {
   1528 		if (handle->opt.promisc) {
   1529 			handle->opt.promisc = 0;
   1530 			/* Just a warning. */
   1531 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   1532 			    "Promiscuous mode not supported on the \"any\" device");
   1533 			status = PCAP_WARNING_PROMISC_NOTSUP;
   1534 		}
   1535 	}
   1536 
   1537 	handlep->device	= strdup(device);
   1538 	if (handlep->device == NULL) {
   1539 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   1540 		    errno, "strdup");
   1541 		return PCAP_ERROR;
   1542 	}
   1543 
   1544 	/* copy timeout value */
   1545 	handlep->timeout = handle->opt.timeout;
   1546 
   1547 	/*
   1548 	 * If we're in promiscuous mode, then we probably want
   1549 	 * to see when the interface drops packets too, so get an
   1550 	 * initial count from /proc/net/dev
   1551 	 */
   1552 	if (handle->opt.promisc)
   1553 		handlep->proc_dropped = linux_if_drops(handlep->device);
   1554 
   1555 	/*
   1556 	 * Current Linux kernels use the protocol family PF_PACKET to
   1557 	 * allow direct access to all packets on the network while
   1558 	 * older kernels had a special socket type SOCK_PACKET to
   1559 	 * implement this feature.
   1560 	 * While this old implementation is kind of obsolete we need
   1561 	 * to be compatible with older kernels for a while so we are
   1562 	 * trying both methods with the newer method preferred.
   1563 	 */
   1564 	ret = activate_new(handle);
   1565 	if (ret < 0) {
   1566 		/*
   1567 		 * Fatal error with the new way; just fail.
   1568 		 * ret has the error return; if it's PCAP_ERROR,
   1569 		 * handle->errbuf has been set appropriately.
   1570 		 */
   1571 		status = ret;
   1572 		goto fail;
   1573 	}
   1574 	if (ret == 1) {
   1575 		/*
   1576 		 * Success.
   1577 		 * Try to use memory-mapped access.
   1578 		 */
   1579 		switch (activate_mmap(handle, &status)) {
   1580 
   1581 		case 1:
   1582 			/*
   1583 			 * We succeeded.  status has been
   1584 			 * set to the status to return,
   1585 			 * which might be 0, or might be
   1586 			 * a PCAP_WARNING_ value.
   1587 			 *
   1588 			 * Set the timeout to use in poll() before
   1589 			 * returning.
   1590 			 */
   1591 			set_poll_timeout(handlep);
   1592 			return status;
   1593 
   1594 		case 0:
   1595 			/*
   1596 			 * Kernel doesn't support it - just continue
   1597 			 * with non-memory-mapped access.
   1598 			 */
   1599 			break;
   1600 
   1601 		case -1:
   1602 			/*
   1603 			 * We failed to set up to use it, or the kernel
   1604 			 * supports it, but we failed to enable it.
   1605 			 * ret has been set to the error status to
   1606 			 * return and, if it's PCAP_ERROR, handle->errbuf
   1607 			 * contains the error message.
   1608 			 */
   1609 			status = ret;
   1610 			goto fail;
   1611 		}
   1612 	}
   1613 	else if (ret == 0) {
   1614 		/* Non-fatal error; try old way */
   1615 		if ((ret = activate_old(handle)) != 1) {
   1616 			/*
   1617 			 * Both methods to open the packet socket failed.
   1618 			 * Tidy up and report our failure (handle->errbuf
   1619 			 * is expected to be set by the functions above).
   1620 			 */
   1621 			status = ret;
   1622 			goto fail;
   1623 		}
   1624 	}
   1625 
   1626 	/*
   1627 	 * We set up the socket, but not with memory-mapped access.
   1628 	 */
   1629 	if (handle->opt.buffer_size != 0) {
   1630 		/*
   1631 		 * Set the socket buffer size to the specified value.
   1632 		 */
   1633 		if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
   1634 		    &handle->opt.buffer_size,
   1635 		    sizeof(handle->opt.buffer_size)) == -1) {
   1636 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   1637 			    PCAP_ERRBUF_SIZE, errno, "SO_RCVBUF");
   1638 			status = PCAP_ERROR;
   1639 			goto fail;
   1640 		}
   1641 	}
   1642 
   1643 	/* Allocate the buffer */
   1644 
   1645 	handle->buffer	 = malloc(handle->bufsize + handle->offset);
   1646 	if (!handle->buffer) {
   1647 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   1648 		    errno, "malloc");
   1649 		status = PCAP_ERROR;
   1650 		goto fail;
   1651 	}
   1652 
   1653 	/*
   1654 	 * "handle->fd" is a socket, so "select()" and "poll()"
   1655 	 * should work on it.
   1656 	 */
   1657 	handle->selectable_fd = handle->fd;
   1658 
   1659 	return status;
   1660 
   1661 fail:
   1662 	pcap_cleanup_linux(handle);
   1663 	return status;
   1664 }
   1665 
   1666 /*
   1667  *  Read at most max_packets from the capture stream and call the callback
   1668  *  for each of them. Returns the number of packets handled or -1 if an
   1669  *  error occured.
   1670  */
   1671 static int
   1672 pcap_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
   1673 {
   1674 	/*
   1675 	 * Currently, on Linux only one packet is delivered per read,
   1676 	 * so we don't loop.
   1677 	 */
   1678 	return pcap_read_packet(handle, callback, user);
   1679 }
   1680 
   1681 static int
   1682 pcap_set_datalink_linux(pcap_t *handle, int dlt)
   1683 {
   1684 	handle->linktype = dlt;
   1685 	return 0;
   1686 }
   1687 
   1688 /*
   1689  * linux_check_direction()
   1690  *
   1691  * Do checks based on packet direction.
   1692  */
   1693 static inline int
   1694 linux_check_direction(const pcap_t *handle, const struct sockaddr_ll *sll)
   1695 {
   1696 	struct pcap_linux	*handlep = handle->priv;
   1697 
   1698 	if (sll->sll_pkttype == PACKET_OUTGOING) {
   1699 		/*
   1700 		 * Outgoing packet.
   1701 		 * If this is from the loopback device, reject it;
   1702 		 * we'll see the packet as an incoming packet as well,
   1703 		 * and we don't want to see it twice.
   1704 		 */
   1705 		if (sll->sll_ifindex == handlep->lo_ifindex)
   1706 			return 0;
   1707 
   1708 		/*
   1709 		 * If this is an outgoing CAN or CAN FD frame, and
   1710 		 * the user doesn't only want outgoing packets,
   1711 		 * reject it; CAN devices and drivers, and the CAN
   1712 		 * stack, always arrange to loop back transmitted
   1713 		 * packets, so they also appear as incoming packets.
   1714 		 * We don't want duplicate packets, and we can't
   1715 		 * easily distinguish packets looped back by the CAN
   1716 		 * layer than those received by the CAN layer, so we
   1717 		 * eliminate this packet instead.
   1718 		 */
   1719 		if ((sll->sll_protocol == LINUX_SLL_P_CAN ||
   1720 		     sll->sll_protocol == LINUX_SLL_P_CANFD) &&
   1721 		     handle->direction != PCAP_D_OUT)
   1722 			return 0;
   1723 
   1724 		/*
   1725 		 * If the user only wants incoming packets, reject it.
   1726 		 */
   1727 		if (handle->direction == PCAP_D_IN)
   1728 			return 0;
   1729 	} else {
   1730 		/*
   1731 		 * Incoming packet.
   1732 		 * If the user only wants outgoing packets, reject it.
   1733 		 */
   1734 		if (handle->direction == PCAP_D_OUT)
   1735 			return 0;
   1736 	}
   1737 	return 1;
   1738 }
   1739 
   1740 /*
   1741  *  Read a packet from the socket calling the handler provided by
   1742  *  the user. Returns the number of packets received or -1 if an
   1743  *  error occured.
   1744  */
   1745 static int
   1746 pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
   1747 {
   1748 	struct pcap_linux	*handlep = handle->priv;
   1749 	u_char			*bp;
   1750 	int			offset;
   1751 #ifdef HAVE_PF_PACKET_SOCKETS
   1752 	struct sockaddr_ll	from;
   1753 	struct sll_header	*hdrp;
   1754 #else
   1755 	struct sockaddr		from;
   1756 #endif
   1757 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
   1758 	struct iovec		iov;
   1759 	struct msghdr		msg;
   1760 	struct cmsghdr		*cmsg;
   1761 	union {
   1762 		struct cmsghdr	cmsg;
   1763 		char		buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))];
   1764 	} cmsg_buf;
   1765 #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1766 	socklen_t		fromlen;
   1767 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1768 	int			packet_len, caplen;
   1769 	struct pcap_pkthdr	pcap_header;
   1770 
   1771         struct bpf_aux_data     aux_data;
   1772 #ifdef HAVE_PF_PACKET_SOCKETS
   1773 	/*
   1774 	 * If this is a cooked device, leave extra room for a
   1775 	 * fake packet header.
   1776 	 */
   1777 	if (handlep->cooked)
   1778 		offset = SLL_HDR_LEN;
   1779 	else
   1780 		offset = 0;
   1781 #else
   1782 	/*
   1783 	 * This system doesn't have PF_PACKET sockets, so it doesn't
   1784 	 * support cooked devices.
   1785 	 */
   1786 	offset = 0;
   1787 #endif
   1788 
   1789 	/*
   1790 	 * Receive a single packet from the kernel.
   1791 	 * We ignore EINTR, as that might just be due to a signal
   1792 	 * being delivered - if the signal should interrupt the
   1793 	 * loop, the signal handler should call pcap_breakloop()
   1794 	 * to set handle->break_loop (we ignore it on other
   1795 	 * platforms as well).
   1796 	 * We also ignore ENETDOWN, so that we can continue to
   1797 	 * capture traffic if the interface goes down and comes
   1798 	 * back up again; comments in the kernel indicate that
   1799 	 * we'll just block waiting for packets if we try to
   1800 	 * receive from a socket that delivered ENETDOWN, and,
   1801 	 * if we're using a memory-mapped buffer, we won't even
   1802 	 * get notified of "network down" events.
   1803 	 */
   1804 	bp = (u_char *)handle->buffer + handle->offset;
   1805 
   1806 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
   1807 	msg.msg_name		= &from;
   1808 	msg.msg_namelen		= sizeof(from);
   1809 	msg.msg_iov		= &iov;
   1810 	msg.msg_iovlen		= 1;
   1811 	msg.msg_control		= &cmsg_buf;
   1812 	msg.msg_controllen	= sizeof(cmsg_buf);
   1813 	msg.msg_flags		= 0;
   1814 
   1815 	iov.iov_len		= handle->bufsize - offset;
   1816 	iov.iov_base		= bp + offset;
   1817 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1818 
   1819 	do {
   1820 		/*
   1821 		 * Has "pcap_breakloop()" been called?
   1822 		 */
   1823 		if (handle->break_loop) {
   1824 			/*
   1825 			 * Yes - clear the flag that indicates that it has,
   1826 			 * and return PCAP_ERROR_BREAK as an indication that
   1827 			 * we were told to break out of the loop.
   1828 			 */
   1829 			handle->break_loop = 0;
   1830 			return PCAP_ERROR_BREAK;
   1831 		}
   1832 
   1833 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
   1834 		packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
   1835 #else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1836 		fromlen = sizeof(from);
   1837 		packet_len = recvfrom(
   1838 			handle->fd, bp + offset,
   1839 			handle->bufsize - offset, MSG_TRUNC,
   1840 			(struct sockaddr *) &from, &fromlen);
   1841 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1842 	} while (packet_len == -1 && errno == EINTR);
   1843 
   1844 	/* Check if an error occured */
   1845 
   1846 	if (packet_len == -1) {
   1847 		switch (errno) {
   1848 
   1849 		case EAGAIN:
   1850 			return 0;	/* no packet there */
   1851 
   1852 		case ENETDOWN:
   1853 			/*
   1854 			 * The device on which we're capturing went away.
   1855 			 *
   1856 			 * XXX - we should really return
   1857 			 * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
   1858 			 * etc. aren't defined to return that.
   1859 			 */
   1860 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   1861 				"The interface went down");
   1862 			return PCAP_ERROR;
   1863 
   1864 		default:
   1865 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   1866 			    PCAP_ERRBUF_SIZE, errno, "recvfrom");
   1867 			return PCAP_ERROR;
   1868 		}
   1869 	}
   1870 
   1871 #ifdef HAVE_PF_PACKET_SOCKETS
   1872 	if (!handlep->sock_packet) {
   1873 		/*
   1874 		 * Unfortunately, there is a window between socket() and
   1875 		 * bind() where the kernel may queue packets from any
   1876 		 * interface.  If we're bound to a particular interface,
   1877 		 * discard packets not from that interface.
   1878 		 *
   1879 		 * (If socket filters are supported, we could do the
   1880 		 * same thing we do when changing the filter; however,
   1881 		 * that won't handle packet sockets without socket
   1882 		 * filter support, and it's a bit more complicated.
   1883 		 * It would save some instructions per packet, however.)
   1884 		 */
   1885 		if (handlep->ifindex != -1 &&
   1886 		    from.sll_ifindex != handlep->ifindex)
   1887 			return 0;
   1888 
   1889 		/*
   1890 		 * Do checks based on packet direction.
   1891 		 * We can only do this if we're using PF_PACKET; the
   1892 		 * address returned for SOCK_PACKET is a "sockaddr_pkt"
   1893 		 * which lacks the relevant packet type information.
   1894 		 */
   1895 		if (!linux_check_direction(handle, &from))
   1896 			return 0;
   1897 	}
   1898 #endif
   1899 
   1900 #ifdef HAVE_PF_PACKET_SOCKETS
   1901 	/*
   1902 	 * If this is a cooked device, fill in the fake packet header.
   1903 	 */
   1904 	if (handlep->cooked) {
   1905 		/*
   1906 		 * Add the length of the fake header to the length
   1907 		 * of packet data we read.
   1908 		 */
   1909 		packet_len += SLL_HDR_LEN;
   1910 
   1911 		hdrp = (struct sll_header *)bp;
   1912 		hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype);
   1913 		hdrp->sll_hatype = htons(from.sll_hatype);
   1914 		hdrp->sll_halen = htons(from.sll_halen);
   1915 		memcpy(hdrp->sll_addr, from.sll_addr,
   1916 		    (from.sll_halen > SLL_ADDRLEN) ?
   1917 		      SLL_ADDRLEN :
   1918 		      from.sll_halen);
   1919 		hdrp->sll_protocol = from.sll_protocol;
   1920 	}
   1921 
   1922 	/*
   1923 	 * Start out with no VLAN information.
   1924 	 */
   1925 	aux_data.vlan_tag_present = 0;
   1926 	aux_data.vlan_tag = 0;
   1927 #if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI)
   1928 	if (handlep->vlan_offset != -1) {
   1929 		for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
   1930 			struct tpacket_auxdata *aux;
   1931 			unsigned int len;
   1932 			struct vlan_tag *tag;
   1933 
   1934 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) ||
   1935 			    cmsg->cmsg_level != SOL_PACKET ||
   1936 			    cmsg->cmsg_type != PACKET_AUXDATA) {
   1937 				/*
   1938 				 * This isn't a PACKET_AUXDATA auxiliary
   1939 				 * data item.
   1940 				 */
   1941 				continue;
   1942 			}
   1943 
   1944 			aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg);
   1945 			if (!VLAN_VALID(aux, aux)) {
   1946 				/*
   1947 				 * There is no VLAN information in the
   1948 				 * auxiliary data.
   1949 				 */
   1950 				continue;
   1951 			}
   1952 
   1953 			len = (u_int)packet_len > iov.iov_len ? iov.iov_len : (u_int)packet_len;
   1954 			if (len < (u_int)handlep->vlan_offset)
   1955 				break;
   1956 
   1957 			/*
   1958 			 * Move everything in the header, except the
   1959 			 * type field, down VLAN_TAG_LEN bytes, to
   1960 			 * allow us to insert the VLAN tag between
   1961 			 * that stuff and the type field.
   1962 			 */
   1963 			bp -= VLAN_TAG_LEN;
   1964 			memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
   1965 
   1966 			/*
   1967 			 * Now insert the tag.
   1968 			 */
   1969 			tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
   1970 			tag->vlan_tpid = htons(VLAN_TPID(aux, aux));
   1971 			tag->vlan_tci = htons(aux->tp_vlan_tci);
   1972 
   1973 			/*
   1974 			 * Save a flag indicating that we have a VLAN tag,
   1975 			 * and the VLAN TCI, to bpf_aux_data struct for
   1976 			 * use by the BPF filter if we're doing the
   1977 			 * filtering in userland.
   1978 			 */
   1979 			aux_data.vlan_tag_present = 1;
   1980 			aux_data.vlan_tag = htons(aux->tp_vlan_tci) & 0x0fff;
   1981 
   1982 			/*
   1983 			 * Add the tag to the packet lengths.
   1984 			 */
   1985 			packet_len += VLAN_TAG_LEN;
   1986 		}
   1987 	}
   1988 #endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_STRUCT_TPACKET_AUXDATA_TP_VLAN_TCI) */
   1989 #endif /* HAVE_PF_PACKET_SOCKETS */
   1990 
   1991 	/*
   1992 	 * XXX: According to the kernel source we should get the real
   1993 	 * packet len if calling recvfrom with MSG_TRUNC set. It does
   1994 	 * not seem to work here :(, but it is supported by this code
   1995 	 * anyway.
   1996 	 * To be honest the code RELIES on that feature so this is really
   1997 	 * broken with 2.2.x kernels.
   1998 	 * I spend a day to figure out what's going on and I found out
   1999 	 * that the following is happening:
   2000 	 *
   2001 	 * The packet comes from a random interface and the packet_rcv
   2002 	 * hook is called with a clone of the packet. That code inserts
   2003 	 * the packet into the receive queue of the packet socket.
   2004 	 * If a filter is attached to that socket that filter is run
   2005 	 * first - and there lies the problem. The default filter always
   2006 	 * cuts the packet at the snaplen:
   2007 	 *
   2008 	 * # tcpdump -d
   2009 	 * (000) ret      #68
   2010 	 *
   2011 	 * So the packet filter cuts down the packet. The recvfrom call
   2012 	 * says "hey, it's only 68 bytes, it fits into the buffer" with
   2013 	 * the result that we don't get the real packet length. This
   2014 	 * is valid at least until kernel 2.2.17pre6.
   2015 	 *
   2016 	 * We currently handle this by making a copy of the filter
   2017 	 * program, fixing all "ret" instructions with non-zero
   2018 	 * operands to have an operand of MAXIMUM_SNAPLEN so that the
   2019 	 * filter doesn't truncate the packet, and supplying that modified
   2020 	 * filter to the kernel.
   2021 	 */
   2022 
   2023 	caplen = packet_len;
   2024 	if (caplen > handle->snapshot)
   2025 		caplen = handle->snapshot;
   2026 
   2027 	/* Run the packet filter if not using kernel filter */
   2028 	if (handlep->filter_in_userland && handle->fcode.bf_insns) {
   2029 		if (bpf_filter_with_aux_data(handle->fcode.bf_insns, bp,
   2030 		    packet_len, caplen, &aux_data) == 0) {
   2031 			/* rejected by filter */
   2032 			return 0;
   2033 		}
   2034 	}
   2035 
   2036 	/* Fill in our own header data */
   2037 
   2038 	/* get timestamp for this packet */
   2039 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
   2040 	if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
   2041 		if (ioctl(handle->fd, SIOCGSTAMPNS, &pcap_header.ts) == -1) {
   2042 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   2043 			    PCAP_ERRBUF_SIZE, errno, "SIOCGSTAMPNS");
   2044 			return PCAP_ERROR;
   2045 		}
   2046         } else
   2047 #endif
   2048 	{
   2049 		if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
   2050 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   2051 			    PCAP_ERRBUF_SIZE, errno, "SIOCGSTAMP");
   2052 			return PCAP_ERROR;
   2053 		}
   2054         }
   2055 
   2056 	pcap_header.caplen	= caplen;
   2057 	pcap_header.len		= packet_len;
   2058 
   2059 	/*
   2060 	 * Count the packet.
   2061 	 *
   2062 	 * Arguably, we should count them before we check the filter,
   2063 	 * as on many other platforms "ps_recv" counts packets
   2064 	 * handed to the filter rather than packets that passed
   2065 	 * the filter, but if filtering is done in the kernel, we
   2066 	 * can't get a count of packets that passed the filter,
   2067 	 * and that would mean the meaning of "ps_recv" wouldn't
   2068 	 * be the same on all Linux systems.
   2069 	 *
   2070 	 * XXX - it's not the same on all systems in any case;
   2071 	 * ideally, we should have a "get the statistics" call
   2072 	 * that supplies more counts and indicates which of them
   2073 	 * it supplies, so that we supply a count of packets
   2074 	 * handed to the filter only on platforms where that
   2075 	 * information is available.
   2076 	 *
   2077 	 * We count them here even if we can get the packet count
   2078 	 * from the kernel, as we can only determine at run time
   2079 	 * whether we'll be able to get it from the kernel (if
   2080 	 * HAVE_STRUCT_TPACKET_STATS isn't defined, we can't get it from
   2081 	 * the kernel, but if it is defined, the library might
   2082 	 * have been built with a 2.4 or later kernel, but we
   2083 	 * might be running on a 2.2[.x] kernel without Alexey
   2084 	 * Kuznetzov's turbopacket patches, and thus the kernel
   2085 	 * might not be able to supply those statistics).  We
   2086 	 * could, I guess, try, when opening the socket, to get
   2087 	 * the statistics, and if we can not increment the count
   2088 	 * here, but it's not clear that always incrementing
   2089 	 * the count is more expensive than always testing a flag
   2090 	 * in memory.
   2091 	 *
   2092 	 * We keep the count in "handlep->packets_read", and use that
   2093 	 * for "ps_recv" if we can't get the statistics from the kernel.
   2094 	 * We do that because, if we *can* get the statistics from
   2095 	 * the kernel, we use "handlep->stat.ps_recv" and
   2096 	 * "handlep->stat.ps_drop" as running counts, as reading the
   2097 	 * statistics from the kernel resets the kernel statistics,
   2098 	 * and if we directly increment "handlep->stat.ps_recv" here,
   2099 	 * that means it will count packets *twice* on systems where
   2100 	 * we can get kernel statistics - once here, and once in
   2101 	 * pcap_stats_linux().
   2102 	 */
   2103 	handlep->packets_read++;
   2104 
   2105 	/* Call the user supplied callback function */
   2106 	callback(userdata, &pcap_header, bp);
   2107 
   2108 	return 1;
   2109 }
   2110 
   2111 static int
   2112 pcap_inject_linux(pcap_t *handle, const void *buf, size_t size)
   2113 {
   2114 	struct pcap_linux *handlep = handle->priv;
   2115 	int ret;
   2116 
   2117 #ifdef HAVE_PF_PACKET_SOCKETS
   2118 	if (!handlep->sock_packet) {
   2119 		/* PF_PACKET socket */
   2120 		if (handlep->ifindex == -1) {
   2121 			/*
   2122 			 * We don't support sending on the "any" device.
   2123 			 */
   2124 			strlcpy(handle->errbuf,
   2125 			    "Sending packets isn't supported on the \"any\" device",
   2126 			    PCAP_ERRBUF_SIZE);
   2127 			return (-1);
   2128 		}
   2129 
   2130 		if (handlep->cooked) {
   2131 			/*
   2132 			 * We don't support sending on the "any" device.
   2133 			 *
   2134 			 * XXX - how do you send on a bound cooked-mode
   2135 			 * socket?
   2136 			 * Is a "sendto()" required there?
   2137 			 */
   2138 			strlcpy(handle->errbuf,
   2139 			    "Sending packets isn't supported in cooked mode",
   2140 			    PCAP_ERRBUF_SIZE);
   2141 			return (-1);
   2142 		}
   2143 	}
   2144 #endif
   2145 
   2146 	ret = send(handle->fd, buf, size, 0);
   2147 	if (ret == -1) {
   2148 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   2149 		    errno, "send");
   2150 		return (-1);
   2151 	}
   2152 	return (ret);
   2153 }
   2154 
   2155 /*
   2156  *  Get the statistics for the given packet capture handle.
   2157  *  Reports the number of dropped packets iff the kernel supports
   2158  *  the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
   2159  *  kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
   2160  *  patches); otherwise, that information isn't available, and we lie
   2161  *  and report 0 as the count of dropped packets.
   2162  */
   2163 static int
   2164 pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
   2165 {
   2166 	struct pcap_linux *handlep = handle->priv;
   2167 #ifdef HAVE_STRUCT_TPACKET_STATS
   2168 #ifdef HAVE_TPACKET3
   2169 	/*
   2170 	 * For sockets using TPACKET_V1 or TPACKET_V2, the extra
   2171 	 * stuff at the end of a struct tpacket_stats_v3 will not
   2172 	 * be filled in, and we don't look at it so this is OK even
   2173 	 * for those sockets.  In addition, the PF_PACKET socket
   2174 	 * code in the kernel only uses the length parameter to
   2175 	 * compute how much data to copy out and to indicate how
   2176 	 * much data was copied out, so it's OK to base it on the
   2177 	 * size of a struct tpacket_stats.
   2178 	 *
   2179 	 * XXX - it's probably OK, in fact, to just use a
   2180 	 * struct tpacket_stats for V3 sockets, as we don't
   2181 	 * care about the tp_freeze_q_cnt stat.
   2182 	 */
   2183 	struct tpacket_stats_v3 kstats;
   2184 #else /* HAVE_TPACKET3 */
   2185 	struct tpacket_stats kstats;
   2186 #endif /* HAVE_TPACKET3 */
   2187 	socklen_t len = sizeof (struct tpacket_stats);
   2188 #endif /* HAVE_STRUCT_TPACKET_STATS */
   2189 
   2190 	long if_dropped = 0;
   2191 
   2192 	/*
   2193 	 *	To fill in ps_ifdrop, we parse /proc/net/dev for the number
   2194 	 */
   2195 	if (handle->opt.promisc)
   2196 	{
   2197 		if_dropped = handlep->proc_dropped;
   2198 		handlep->proc_dropped = linux_if_drops(handlep->device);
   2199 		handlep->stat.ps_ifdrop += (handlep->proc_dropped - if_dropped);
   2200 	}
   2201 
   2202 #ifdef HAVE_STRUCT_TPACKET_STATS
   2203 	/*
   2204 	 * Try to get the packet counts from the kernel.
   2205 	 */
   2206 	if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
   2207 			&kstats, &len) > -1) {
   2208 		/*
   2209 		 * On systems where the PACKET_STATISTICS "getsockopt()"
   2210 		 * argument is supported on PF_PACKET sockets:
   2211 		 *
   2212 		 *	"ps_recv" counts only packets that *passed* the
   2213 		 *	filter, not packets that didn't pass the filter.
   2214 		 *	This includes packets later dropped because we
   2215 		 *	ran out of buffer space.
   2216 		 *
   2217 		 *	"ps_drop" counts packets dropped because we ran
   2218 		 *	out of buffer space.  It doesn't count packets
   2219 		 *	dropped by the interface driver.  It counts only
   2220 		 *	packets that passed the filter.
   2221 		 *
   2222 		 *	See above for ps_ifdrop.
   2223 		 *
   2224 		 *	Both statistics include packets not yet read from
   2225 		 *	the kernel by libpcap, and thus not yet seen by
   2226 		 *	the application.
   2227 		 *
   2228 		 * In "linux/net/packet/af_packet.c", at least in the
   2229 		 * 2.4.9 kernel, "tp_packets" is incremented for every
   2230 		 * packet that passes the packet filter *and* is
   2231 		 * successfully queued on the socket; "tp_drops" is
   2232 		 * incremented for every packet dropped because there's
   2233 		 * not enough free space in the socket buffer.
   2234 		 *
   2235 		 * When the statistics are returned for a PACKET_STATISTICS
   2236 		 * "getsockopt()" call, "tp_drops" is added to "tp_packets",
   2237 		 * so that "tp_packets" counts all packets handed to
   2238 		 * the PF_PACKET socket, including packets dropped because
   2239 		 * there wasn't room on the socket buffer - but not
   2240 		 * including packets that didn't pass the filter.
   2241 		 *
   2242 		 * In the BSD BPF, the count of received packets is
   2243 		 * incremented for every packet handed to BPF, regardless
   2244 		 * of whether it passed the filter.
   2245 		 *
   2246 		 * We can't make "pcap_stats()" work the same on both
   2247 		 * platforms, but the best approximation is to return
   2248 		 * "tp_packets" as the count of packets and "tp_drops"
   2249 		 * as the count of drops.
   2250 		 *
   2251 		 * Keep a running total because each call to
   2252 		 *    getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, ....
   2253 		 * resets the counters to zero.
   2254 		 */
   2255 		handlep->stat.ps_recv += kstats.tp_packets;
   2256 		handlep->stat.ps_drop += kstats.tp_drops;
   2257 		*stats = handlep->stat;
   2258 		return 0;
   2259 	}
   2260 	else
   2261 	{
   2262 		/*
   2263 		 * If the error was EOPNOTSUPP, fall through, so that
   2264 		 * if you build the library on a system with
   2265 		 * "struct tpacket_stats" and run it on a system
   2266 		 * that doesn't, it works as it does if the library
   2267 		 * is built on a system without "struct tpacket_stats".
   2268 		 */
   2269 		if (errno != EOPNOTSUPP) {
   2270 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   2271 			    PCAP_ERRBUF_SIZE, errno, "pcap_stats");
   2272 			return -1;
   2273 		}
   2274 	}
   2275 #endif
   2276 	/*
   2277 	 * On systems where the PACKET_STATISTICS "getsockopt()" argument
   2278 	 * is not supported on PF_PACKET sockets:
   2279 	 *
   2280 	 *	"ps_recv" counts only packets that *passed* the filter,
   2281 	 *	not packets that didn't pass the filter.  It does not
   2282 	 *	count packets dropped because we ran out of buffer
   2283 	 *	space.
   2284 	 *
   2285 	 *	"ps_drop" is not supported.
   2286 	 *
   2287 	 *	"ps_ifdrop" is supported. It will return the number
   2288 	 *	of drops the interface reports in /proc/net/dev,
   2289 	 *	if that is available.
   2290 	 *
   2291 	 *	"ps_recv" doesn't include packets not yet read from
   2292 	 *	the kernel by libpcap.
   2293 	 *
   2294 	 * We maintain the count of packets processed by libpcap in
   2295 	 * "handlep->packets_read", for reasons described in the comment
   2296 	 * at the end of pcap_read_packet().  We have no idea how many
   2297 	 * packets were dropped by the kernel buffers -- but we know
   2298 	 * how many the interface dropped, so we can return that.
   2299 	 */
   2300 
   2301 	stats->ps_recv = handlep->packets_read;
   2302 	stats->ps_drop = 0;
   2303 	stats->ps_ifdrop = handlep->stat.ps_ifdrop;
   2304 	return 0;
   2305 }
   2306 
   2307 static int
   2308 add_linux_if(pcap_if_list_t *devlistp, const char *ifname, int fd, char *errbuf)
   2309 {
   2310 	const char *p;
   2311 	char name[512];	/* XXX - pick a size */
   2312 	char *q, *saveq;
   2313 	struct ifreq ifrflags;
   2314 
   2315 	/*
   2316 	 * Get the interface name.
   2317 	 */
   2318 	p = ifname;
   2319 	q = &name[0];
   2320 	while (*p != '\0' && isascii(*p) && !isspace(*p)) {
   2321 		if (*p == ':') {
   2322 			/*
   2323 			 * This could be the separator between a
   2324 			 * name and an alias number, or it could be
   2325 			 * the separator between a name with no
   2326 			 * alias number and the next field.
   2327 			 *
   2328 			 * If there's a colon after digits, it
   2329 			 * separates the name and the alias number,
   2330 			 * otherwise it separates the name and the
   2331 			 * next field.
   2332 			 */
   2333 			saveq = q;
   2334 			while (isascii(*p) && isdigit(*p))
   2335 				*q++ = *p++;
   2336 			if (*p != ':') {
   2337 				/*
   2338 				 * That was the next field,
   2339 				 * not the alias number.
   2340 				 */
   2341 				q = saveq;
   2342 			}
   2343 			break;
   2344 		} else
   2345 			*q++ = *p++;
   2346 	}
   2347 	*q = '\0';
   2348 
   2349 	/*
   2350 	 * Get the flags for this interface.
   2351 	 */
   2352 	strlcpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
   2353 	if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
   2354 		if (errno == ENXIO || errno == ENODEV)
   2355 			return (0);	/* device doesn't actually exist - ignore it */
   2356 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2357 		    errno, "SIOCGIFFLAGS: %.*s",
   2358 		    (int)sizeof(ifrflags.ifr_name),
   2359 		    ifrflags.ifr_name);
   2360 		return (-1);
   2361 	}
   2362 
   2363 	/*
   2364 	 * Add an entry for this interface, with no addresses, if it's
   2365 	 * not already in the list.
   2366 	 */
   2367 	if (find_or_add_if(devlistp, name, ifrflags.ifr_flags,
   2368 	    get_if_flags, errbuf) == NULL) {
   2369 		/*
   2370 		 * Failure.
   2371 		 */
   2372 		return (-1);
   2373 	}
   2374 
   2375 	return (0);
   2376 }
   2377 
   2378 /*
   2379  * Get from "/sys/class/net" all interfaces listed there; if they're
   2380  * already in the list of interfaces we have, that won't add another
   2381  * instance, but if they're not, that'll add them.
   2382  *
   2383  * We don't bother getting any addresses for them; it appears you can't
   2384  * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
   2385  * although some other types of addresses can be fetched with SIOCGIFADDR,
   2386  * we don't bother with them for now.
   2387  *
   2388  * We also don't fail if we couldn't open "/sys/class/net"; we just leave
   2389  * the list of interfaces as is, and return 0, so that we can try
   2390  * scanning /proc/net/dev.
   2391  *
   2392  * Otherwise, we return 1 if we don't get an error and -1 if we do.
   2393  */
   2394 static int
   2395 scan_sys_class_net(pcap_if_list_t *devlistp, char *errbuf)
   2396 {
   2397 	DIR *sys_class_net_d;
   2398 	int fd;
   2399 	struct dirent *ent;
   2400 	char subsystem_path[PATH_MAX+1];
   2401 	struct stat statb;
   2402 	int ret = 1;
   2403 
   2404 	sys_class_net_d = opendir("/sys/class/net");
   2405 	if (sys_class_net_d == NULL) {
   2406 		/*
   2407 		 * Don't fail if it doesn't exist at all.
   2408 		 */
   2409 		if (errno == ENOENT)
   2410 			return (0);
   2411 
   2412 		/*
   2413 		 * Fail if we got some other error.
   2414 		 */
   2415 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2416 		    errno, "Can't open /sys/class/net");
   2417 		return (-1);
   2418 	}
   2419 
   2420 	/*
   2421 	 * Create a socket from which to fetch interface information.
   2422 	 */
   2423 	fd = socket(PF_UNIX, SOCK_RAW, 0);
   2424 	if (fd < 0) {
   2425 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2426 		    errno, "socket");
   2427 		(void)closedir(sys_class_net_d);
   2428 		return (-1);
   2429 	}
   2430 
   2431 	for (;;) {
   2432 		errno = 0;
   2433 		ent = readdir(sys_class_net_d);
   2434 		if (ent == NULL) {
   2435 			/*
   2436 			 * Error or EOF; if errno != 0, it's an error.
   2437 			 */
   2438 			break;
   2439 		}
   2440 
   2441 		/*
   2442 		 * Ignore "." and "..".
   2443 		 */
   2444 		if (strcmp(ent->d_name, ".") == 0 ||
   2445 		    strcmp(ent->d_name, "..") == 0)
   2446 			continue;
   2447 
   2448 		/*
   2449 		 * Ignore plain files; they do not have subdirectories
   2450 		 * and thus have no attributes.
   2451 		 */
   2452 		if (ent->d_type == DT_REG)
   2453 			continue;
   2454 
   2455 		/*
   2456 		 * Is there an "ifindex" file under that name?
   2457 		 * (We don't care whether it's a directory or
   2458 		 * a symlink; older kernels have directories
   2459 		 * for devices, newer kernels have symlinks to
   2460 		 * directories.)
   2461 		 */
   2462 		pcap_snprintf(subsystem_path, sizeof subsystem_path,
   2463 		    "/sys/class/net/%s/ifindex", ent->d_name);
   2464 		if (lstat(subsystem_path, &statb) != 0) {
   2465 			/*
   2466 			 * Stat failed.  Either there was an error
   2467 			 * other than ENOENT, and we don't know if
   2468 			 * this is an interface, or it's ENOENT,
   2469 			 * and either some part of "/sys/class/net/{if}"
   2470 			 * disappeared, in which case it probably means
   2471 			 * the interface disappeared, or there's no
   2472 			 * "ifindex" file, which means it's not a
   2473 			 * network interface.
   2474 			 */
   2475 			continue;
   2476 		}
   2477 
   2478 		/*
   2479 		 * Attempt to add the interface.
   2480 		 */
   2481 		if (add_linux_if(devlistp, &ent->d_name[0], fd, errbuf) == -1) {
   2482 			/* Fail. */
   2483 			ret = -1;
   2484 			break;
   2485 		}
   2486 	}
   2487 	if (ret != -1) {
   2488 		/*
   2489 		 * Well, we didn't fail for any other reason; did we
   2490 		 * fail due to an error reading the directory?
   2491 		 */
   2492 		if (errno != 0) {
   2493 			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2494 			    errno, "Error reading /sys/class/net");
   2495 			ret = -1;
   2496 		}
   2497 	}
   2498 
   2499 	(void)close(fd);
   2500 	(void)closedir(sys_class_net_d);
   2501 	return (ret);
   2502 }
   2503 
   2504 /*
   2505  * Get from "/proc/net/dev" all interfaces listed there; if they're
   2506  * already in the list of interfaces we have, that won't add another
   2507  * instance, but if they're not, that'll add them.
   2508  *
   2509  * See comments from scan_sys_class_net().
   2510  */
   2511 static int
   2512 scan_proc_net_dev(pcap_if_list_t *devlistp, char *errbuf)
   2513 {
   2514 	FILE *proc_net_f;
   2515 	int fd;
   2516 	char linebuf[512];
   2517 	int linenum;
   2518 	char *p;
   2519 	int ret = 0;
   2520 
   2521 	proc_net_f = fopen("/proc/net/dev", "r");
   2522 	if (proc_net_f == NULL) {
   2523 		/*
   2524 		 * Don't fail if it doesn't exist at all.
   2525 		 */
   2526 		if (errno == ENOENT)
   2527 			return (0);
   2528 
   2529 		/*
   2530 		 * Fail if we got some other error.
   2531 		 */
   2532 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2533 		    errno, "Can't open /proc/net/dev");
   2534 		return (-1);
   2535 	}
   2536 
   2537 	/*
   2538 	 * Create a socket from which to fetch interface information.
   2539 	 */
   2540 	fd = socket(PF_UNIX, SOCK_RAW, 0);
   2541 	if (fd < 0) {
   2542 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2543 		    errno, "socket");
   2544 		(void)fclose(proc_net_f);
   2545 		return (-1);
   2546 	}
   2547 
   2548 	for (linenum = 1;
   2549 	    fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
   2550 		/*
   2551 		 * Skip the first two lines - they're headers.
   2552 		 */
   2553 		if (linenum <= 2)
   2554 			continue;
   2555 
   2556 		p = &linebuf[0];
   2557 
   2558 		/*
   2559 		 * Skip leading white space.
   2560 		 */
   2561 		while (*p != '\0' && isascii(*p) && isspace(*p))
   2562 			p++;
   2563 		if (*p == '\0' || *p == '\n')
   2564 			continue;	/* blank line */
   2565 
   2566 		/*
   2567 		 * Attempt to add the interface.
   2568 		 */
   2569 		if (add_linux_if(devlistp, p, fd, errbuf) == -1) {
   2570 			/* Fail. */
   2571 			ret = -1;
   2572 			break;
   2573 		}
   2574 	}
   2575 	if (ret != -1) {
   2576 		/*
   2577 		 * Well, we didn't fail for any other reason; did we
   2578 		 * fail due to an error reading the file?
   2579 		 */
   2580 		if (ferror(proc_net_f)) {
   2581 			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2582 			    errno, "Error reading /proc/net/dev");
   2583 			ret = -1;
   2584 		}
   2585 	}
   2586 
   2587 	(void)close(fd);
   2588 	(void)fclose(proc_net_f);
   2589 	return (ret);
   2590 }
   2591 
   2592 /*
   2593  * Description string for the "any" device.
   2594  */
   2595 static const char any_descr[] = "Pseudo-device that captures on all interfaces";
   2596 
   2597 /*
   2598  * A SOCK_PACKET or PF_PACKET socket can be bound to any network interface.
   2599  */
   2600 static int
   2601 can_be_bound(const char *name _U_)
   2602 {
   2603 	return (1);
   2604 }
   2605 
   2606 /*
   2607  * Get additional flags for a device, using SIOCGIFMEDIA.
   2608  */
   2609 static int
   2610 get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
   2611 {
   2612 	int sock;
   2613 	FILE *fh;
   2614 	unsigned int arptype;
   2615 	struct ifreq ifr;
   2616 	struct ethtool_value info;
   2617 
   2618 	if (*flags & PCAP_IF_LOOPBACK) {
   2619 		/*
   2620 		 * Loopback devices aren't wireless, and "connected"/
   2621 		 * "disconnected" doesn't apply to them.
   2622 		 */
   2623 		*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
   2624 		return 0;
   2625 	}
   2626 
   2627 	sock = socket(AF_INET, SOCK_DGRAM, 0);
   2628 	if (sock == -1) {
   2629 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, errno,
   2630 		    "Can't create socket to get ethtool information for %s",
   2631 		    name);
   2632 		return -1;
   2633 	}
   2634 
   2635 	/*
   2636 	 * OK, what type of network is this?
   2637 	 * In particular, is it wired or wireless?
   2638 	 */
   2639 	if (is_wifi(sock, name)) {
   2640 		/*
   2641 		 * Wi-Fi, hence wireless.
   2642 		 */
   2643 		*flags |= PCAP_IF_WIRELESS;
   2644 	} else {
   2645 		/*
   2646 		 * OK, what does /sys/class/net/{if}/type contain?
   2647 		 * (We don't use that for Wi-Fi, as it'll report
   2648 		 * "Ethernet", i.e. ARPHRD_ETHER, for non-monitor-
   2649 		 * mode devices.)
   2650 		 */
   2651 		char *pathstr;
   2652 
   2653 		if (asprintf(&pathstr, "/sys/class/net/%s/type", name) == -1) {
   2654 			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
   2655 			    "%s: Can't generate path name string for /sys/class/net device",
   2656 			    name);
   2657 			close(sock);
   2658 			return -1;
   2659 		}
   2660 		fh = fopen(pathstr, "r");
   2661 		if (fh != NULL) {
   2662 			if (fscanf(fh, "%u", &arptype) == 1) {
   2663 				/*
   2664 				 * OK, we got an ARPHRD_ type; what is it?
   2665 				 */
   2666 				switch (arptype) {
   2667 
   2668 #ifdef ARPHRD_LOOPBACK
   2669 				case ARPHRD_LOOPBACK:
   2670 					/*
   2671 					 * These are types to which
   2672 					 * "connected" and "disconnected"
   2673 					 * don't apply, so don't bother
   2674 					 * asking about it.
   2675 					 *
   2676 					 * XXX - add other types?
   2677 					 */
   2678 					close(sock);
   2679 					fclose(fh);
   2680 					free(pathstr);
   2681 					return 0;
   2682 #endif
   2683 
   2684 				case ARPHRD_IRDA:
   2685 				case ARPHRD_IEEE80211:
   2686 				case ARPHRD_IEEE80211_PRISM:
   2687 				case ARPHRD_IEEE80211_RADIOTAP:
   2688 #ifdef ARPHRD_IEEE802154
   2689 				case ARPHRD_IEEE802154:
   2690 #endif
   2691 #ifdef ARPHRD_IEEE802154_MONITOR
   2692 				case ARPHRD_IEEE802154_MONITOR:
   2693 #endif
   2694 #ifdef ARPHRD_6LOWPAN
   2695 				case ARPHRD_6LOWPAN:
   2696 #endif
   2697 					/*
   2698 					 * Various wireless types.
   2699 					 */
   2700 					*flags |= PCAP_IF_WIRELESS;
   2701 					break;
   2702 				}
   2703 			}
   2704 			fclose(fh);
   2705 			free(pathstr);
   2706 		}
   2707 	}
   2708 
   2709 #ifdef ETHTOOL_GLINK
   2710 	memset(&ifr, 0, sizeof(ifr));
   2711 	strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
   2712 	info.cmd = ETHTOOL_GLINK;
   2713 	ifr.ifr_data = (caddr_t)&info;
   2714 	if (ioctl(sock, SIOCETHTOOL, &ifr) == -1) {
   2715 		int save_errno = errno;
   2716 
   2717 		switch (save_errno) {
   2718 
   2719 		case EOPNOTSUPP:
   2720 		case EINVAL:
   2721 			/*
   2722 			 * OK, this OS version or driver doesn't support
   2723 			 * asking for this information.
   2724 			 * XXX - distinguish between "this doesn't
   2725 			 * support ethtool at all because it's not
   2726 			 * that type of device" vs. "this doesn't
   2727 			 * support ethtool even though it's that
   2728 			 * type of device", and return "unknown".
   2729 			 */
   2730 			*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
   2731 			close(sock);
   2732 			return 0;
   2733 
   2734 		case ENODEV:
   2735 			/*
   2736 			 * OK, no such device.
   2737 			 * The user will find that out when they try to
   2738 			 * activate the device; just say "OK" and
   2739 			 * don't set anything.
   2740 			 */
   2741 			close(sock);
   2742 			return 0;
   2743 
   2744 		default:
   2745 			/*
   2746 			 * Other error.
   2747 			 */
   2748 			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
   2749 			    save_errno,
   2750 			    "%s: SIOCETHTOOL(ETHTOOL_GLINK) ioctl failed",
   2751 			    name);
   2752 			close(sock);
   2753 			return -1;
   2754 		}
   2755 	}
   2756 
   2757 	/*
   2758 	 * Is it connected?
   2759 	 */
   2760 	if (info.data) {
   2761 		/*
   2762 		 * It's connected.
   2763 		 */
   2764 		*flags |= PCAP_IF_CONNECTION_STATUS_CONNECTED;
   2765 	} else {
   2766 		/*
   2767 		 * It's disconnected.
   2768 		 */
   2769 		*flags |= PCAP_IF_CONNECTION_STATUS_DISCONNECTED;
   2770 	}
   2771 #endif
   2772 
   2773 	close(sock);
   2774 	return 0;
   2775 }
   2776 
   2777 int
   2778 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
   2779 {
   2780 	int ret;
   2781 
   2782 	/*
   2783 	 * Get the list of regular interfaces first.
   2784 	 */
   2785 	if (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
   2786 	    get_if_flags) == -1)
   2787 		return (-1);	/* failure */
   2788 
   2789 	/*
   2790 	 * Read "/sys/class/net", and add to the list of interfaces all
   2791 	 * interfaces listed there that we don't already have, because,
   2792 	 * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
   2793 	 * and even getifaddrs() won't return information about
   2794 	 * interfaces with no addresses, so you need to read "/sys/class/net"
   2795 	 * to get the names of the rest of the interfaces.
   2796 	 */
   2797 	ret = scan_sys_class_net(devlistp, errbuf);
   2798 	if (ret == -1)
   2799 		return (-1);	/* failed */
   2800 	if (ret == 0) {
   2801 		/*
   2802 		 * No /sys/class/net; try reading /proc/net/dev instead.
   2803 		 */
   2804 		if (scan_proc_net_dev(devlistp, errbuf) == -1)
   2805 			return (-1);
   2806 	}
   2807 
   2808 	/*
   2809 	 * Add the "any" device.
   2810 	 * As it refers to all network devices, not to any particular
   2811 	 * network device, the notion of "connected" vs. "disconnected"
   2812 	 * doesn't apply.
   2813 	 */
   2814 	if (add_dev(devlistp, "any",
   2815 	    PCAP_IF_UP|PCAP_IF_RUNNING|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
   2816 	    any_descr, errbuf) == NULL)
   2817 		return (-1);
   2818 
   2819 	return (0);
   2820 }
   2821 
   2822 /*
   2823  *  Attach the given BPF code to the packet capture device.
   2824  */
   2825 static int
   2826 pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
   2827     int is_mmapped)
   2828 {
   2829 	struct pcap_linux *handlep;
   2830 #ifdef SO_ATTACH_FILTER
   2831 	struct sock_fprog	fcode;
   2832 	int			can_filter_in_kernel;
   2833 	int			err = 0;
   2834 #endif
   2835 
   2836 	if (!handle)
   2837 		return -1;
   2838 	if (!filter) {
   2839 	        strlcpy(handle->errbuf, "setfilter: No filter specified",
   2840 			PCAP_ERRBUF_SIZE);
   2841 		return -1;
   2842 	}
   2843 
   2844 	handlep = handle->priv;
   2845 
   2846 	/* Make our private copy of the filter */
   2847 
   2848 	if (install_bpf_program(handle, filter) < 0)
   2849 		/* install_bpf_program() filled in errbuf */
   2850 		return -1;
   2851 
   2852 	/*
   2853 	 * Run user level packet filter by default. Will be overriden if
   2854 	 * installing a kernel filter succeeds.
   2855 	 */
   2856 	handlep->filter_in_userland = 1;
   2857 
   2858 	/* Install kernel level filter if possible */
   2859 
   2860 #ifdef SO_ATTACH_FILTER
   2861 #ifdef USHRT_MAX
   2862 	if (handle->fcode.bf_len > USHRT_MAX) {
   2863 		/*
   2864 		 * fcode.len is an unsigned short for current kernel.
   2865 		 * I have yet to see BPF-Code with that much
   2866 		 * instructions but still it is possible. So for the
   2867 		 * sake of correctness I added this check.
   2868 		 */
   2869 		fprintf(stderr, "Warning: Filter too complex for kernel\n");
   2870 		fcode.len = 0;
   2871 		fcode.filter = NULL;
   2872 		can_filter_in_kernel = 0;
   2873 	} else
   2874 #endif /* USHRT_MAX */
   2875 	{
   2876 		/*
   2877 		 * Oh joy, the Linux kernel uses struct sock_fprog instead
   2878 		 * of struct bpf_program and of course the length field is
   2879 		 * of different size. Pointed out by Sebastian
   2880 		 *
   2881 		 * Oh, and we also need to fix it up so that all "ret"
   2882 		 * instructions with non-zero operands have MAXIMUM_SNAPLEN
   2883 		 * as the operand if we're not capturing in memory-mapped
   2884 		 * mode, and so that, if we're in cooked mode, all memory-
   2885 		 * reference instructions use special magic offsets in
   2886 		 * references to the link-layer header and assume that the
   2887 		 * link-layer payload begins at 0; "fix_program()" will do
   2888 		 * that.
   2889 		 */
   2890 		switch (fix_program(handle, &fcode, is_mmapped)) {
   2891 
   2892 		case -1:
   2893 		default:
   2894 			/*
   2895 			 * Fatal error; just quit.
   2896 			 * (The "default" case shouldn't happen; we
   2897 			 * return -1 for that reason.)
   2898 			 */
   2899 			return -1;
   2900 
   2901 		case 0:
   2902 			/*
   2903 			 * The program performed checks that we can't make
   2904 			 * work in the kernel.
   2905 			 */
   2906 			can_filter_in_kernel = 0;
   2907 			break;
   2908 
   2909 		case 1:
   2910 			/*
   2911 			 * We have a filter that'll work in the kernel.
   2912 			 */
   2913 			can_filter_in_kernel = 1;
   2914 			break;
   2915 		}
   2916 	}
   2917 
   2918 	/*
   2919 	 * NOTE: at this point, we've set both the "len" and "filter"
   2920 	 * fields of "fcode".  As of the 2.6.32.4 kernel, at least,
   2921 	 * those are the only members of the "sock_fprog" structure,
   2922 	 * so we initialize every member of that structure.
   2923 	 *
   2924 	 * If there is anything in "fcode" that is not initialized,
   2925 	 * it is either a field added in a later kernel, or it's
   2926 	 * padding.
   2927 	 *
   2928 	 * If a new field is added, this code needs to be updated
   2929 	 * to set it correctly.
   2930 	 *
   2931 	 * If there are no other fields, then:
   2932 	 *
   2933 	 *	if the Linux kernel looks at the padding, it's
   2934 	 *	buggy;
   2935 	 *
   2936 	 *	if the Linux kernel doesn't look at the padding,
   2937 	 *	then if some tool complains that we're passing
   2938 	 *	uninitialized data to the kernel, then the tool
   2939 	 *	is buggy and needs to understand that it's just
   2940 	 *	padding.
   2941 	 */
   2942 	if (can_filter_in_kernel) {
   2943 		if ((err = set_kernel_filter(handle, &fcode)) == 0)
   2944 		{
   2945 			/*
   2946 			 * Installation succeded - using kernel filter,
   2947 			 * so userland filtering not needed.
   2948 			 */
   2949 			handlep->filter_in_userland = 0;
   2950 		}
   2951 		else if (err == -1)	/* Non-fatal error */
   2952 		{
   2953 			/*
   2954 			 * Print a warning if we weren't able to install
   2955 			 * the filter for a reason other than "this kernel
   2956 			 * isn't configured to support socket filters.
   2957 			 */
   2958 			if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
   2959 				fprintf(stderr,
   2960 				    "Warning: Kernel filter failed: %s\n",
   2961 					pcap_strerror(errno));
   2962 			}
   2963 		}
   2964 	}
   2965 
   2966 	/*
   2967 	 * If we're not using the kernel filter, get rid of any kernel
   2968 	 * filter that might've been there before, e.g. because the
   2969 	 * previous filter could work in the kernel, or because some other
   2970 	 * code attached a filter to the socket by some means other than
   2971 	 * calling "pcap_setfilter()".  Otherwise, the kernel filter may
   2972 	 * filter out packets that would pass the new userland filter.
   2973 	 */
   2974 	if (handlep->filter_in_userland) {
   2975 		if (reset_kernel_filter(handle) == -1) {
   2976 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   2977 			    PCAP_ERRBUF_SIZE, errno,
   2978 			    "can't remove kernel filter");
   2979 			err = -2;	/* fatal error */
   2980 		}
   2981 	}
   2982 
   2983 	/*
   2984 	 * Free up the copy of the filter that was made by "fix_program()".
   2985 	 */
   2986 	if (fcode.filter != NULL)
   2987 		free(fcode.filter);
   2988 
   2989 	if (err == -2)
   2990 		/* Fatal error */
   2991 		return -1;
   2992 #endif /* SO_ATTACH_FILTER */
   2993 
   2994 	return 0;
   2995 }
   2996 
   2997 static int
   2998 pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
   2999 {
   3000 	return pcap_setfilter_linux_common(handle, filter, 0);
   3001 }
   3002 
   3003 
   3004 /*
   3005  * Set direction flag: Which packets do we accept on a forwarding
   3006  * single device? IN, OUT or both?
   3007  */
   3008 static int
   3009 pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d)
   3010 {
   3011 #ifdef HAVE_PF_PACKET_SOCKETS
   3012 	struct pcap_linux *handlep = handle->priv;
   3013 
   3014 	if (!handlep->sock_packet) {
   3015 		handle->direction = d;
   3016 		return 0;
   3017 	}
   3018 #endif
   3019 	/*
   3020 	 * We're not using PF_PACKET sockets, so we can't determine
   3021 	 * the direction of the packet.
   3022 	 */
   3023 	pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   3024 	    "Setting direction is not supported on SOCK_PACKET sockets");
   3025 	return -1;
   3026 }
   3027 
   3028 #ifdef HAVE_PF_PACKET_SOCKETS
   3029 /*
   3030  * Map the PACKET_ value to a LINUX_SLL_ value; we
   3031  * want the same numerical value to be used in
   3032  * the link-layer header even if the numerical values
   3033  * for the PACKET_ #defines change, so that programs
   3034  * that look at the packet type field will always be
   3035  * able to handle DLT_LINUX_SLL captures.
   3036  */
   3037 static short int
   3038 map_packet_type_to_sll_type(short int sll_pkttype)
   3039 {
   3040 	switch (sll_pkttype) {
   3041 
   3042 	case PACKET_HOST:
   3043 		return htons(LINUX_SLL_HOST);
   3044 
   3045 	case PACKET_BROADCAST:
   3046 		return htons(LINUX_SLL_BROADCAST);
   3047 
   3048 	case PACKET_MULTICAST:
   3049 		return  htons(LINUX_SLL_MULTICAST);
   3050 
   3051 	case PACKET_OTHERHOST:
   3052 		return htons(LINUX_SLL_OTHERHOST);
   3053 
   3054 	case PACKET_OUTGOING:
   3055 		return htons(LINUX_SLL_OUTGOING);
   3056 
   3057 	default:
   3058 		return -1;
   3059 	}
   3060 }
   3061 #endif
   3062 
   3063 static int
   3064 is_wifi(int sock_fd
   3065 #ifndef IW_MODE_MONITOR
   3066 _U_
   3067 #endif
   3068 , const char *device)
   3069 {
   3070 	char *pathstr;
   3071 	struct stat statb;
   3072 #ifdef IW_MODE_MONITOR
   3073 	char errbuf[PCAP_ERRBUF_SIZE];
   3074 #endif
   3075 
   3076 	/*
   3077 	 * See if there's a sysfs wireless directory for it.
   3078 	 * If so, it's a wireless interface.
   3079 	 */
   3080 	if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
   3081 		/*
   3082 		 * Just give up here.
   3083 		 */
   3084 		return 0;
   3085 	}
   3086 	if (stat(pathstr, &statb) == 0) {
   3087 		free(pathstr);
   3088 		return 1;
   3089 	}
   3090 	free(pathstr);
   3091 
   3092 #ifdef IW_MODE_MONITOR
   3093 	/*
   3094 	 * OK, maybe it's not wireless, or maybe this kernel doesn't
   3095 	 * support sysfs.  Try the wireless extensions.
   3096 	 */
   3097 	if (has_wext(sock_fd, device, errbuf) == 1) {
   3098 		/*
   3099 		 * It supports the wireless extensions, so it's a Wi-Fi
   3100 		 * device.
   3101 		 */
   3102 		return 1;
   3103 	}
   3104 #endif
   3105 	return 0;
   3106 }
   3107 
   3108 /*
   3109  *  Linux uses the ARP hardware type to identify the type of an
   3110  *  interface. pcap uses the DLT_xxx constants for this. This
   3111  *  function takes a pointer to a "pcap_t", and an ARPHRD_xxx
   3112  *  constant, as arguments, and sets "handle->linktype" to the
   3113  *  appropriate DLT_XXX constant and sets "handle->offset" to
   3114  *  the appropriate value (to make "handle->offset" plus link-layer
   3115  *  header length be a multiple of 4, so that the link-layer payload
   3116  *  will be aligned on a 4-byte boundary when capturing packets).
   3117  *  (If the offset isn't set here, it'll be 0; add code as appropriate
   3118  *  for cases where it shouldn't be 0.)
   3119  *
   3120  *  If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
   3121  *  in cooked mode; otherwise, we can't use cooked mode, so we have
   3122  *  to pick some type that works in raw mode, or fail.
   3123  *
   3124  *  Sets the link type to -1 if unable to map the type.
   3125  */
   3126 static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype,
   3127 			      const char *device, int cooked_ok)
   3128 {
   3129 	static const char cdma_rmnet[] = "cdma_rmnet";
   3130 
   3131 	switch (arptype) {
   3132 
   3133 	case ARPHRD_ETHER:
   3134 		/*
   3135 		 * For various annoying reasons having to do with DHCP
   3136 		 * software, some versions of Android give the mobile-
   3137 		 * phone-network interface an ARPHRD_ value of
   3138 		 * ARPHRD_ETHER, even though the packets supplied by
   3139 		 * that interface have no link-layer header, and begin
   3140 		 * with an IP header, so that the ARPHRD_ value should
   3141 		 * be ARPHRD_NONE.
   3142 		 *
   3143 		 * Detect those devices by checking the device name, and
   3144 		 * use DLT_RAW for them.
   3145 		 */
   3146 		if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
   3147 			handle->linktype = DLT_RAW;
   3148 			return;
   3149 		}
   3150 
   3151 		/*
   3152 		 * Is this a real Ethernet device?  If so, give it a
   3153 		 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
   3154 		 * that an application can let you choose it, in case you're
   3155 		 * capturing DOCSIS traffic that a Cisco Cable Modem
   3156 		 * Termination System is putting out onto an Ethernet (it
   3157 		 * doesn't put an Ethernet header onto the wire, it puts raw
   3158 		 * DOCSIS frames out on the wire inside the low-level
   3159 		 * Ethernet framing).
   3160 		 *
   3161 		 * XXX - are there any other sorts of "fake Ethernet" that
   3162 		 * have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as
   3163 		 * a Cisco CMTS won't put traffic onto it or get traffic
   3164 		 * bridged onto it?  ISDN is handled in "activate_new()",
   3165 		 * as we fall back on cooked mode there, and we use
   3166 		 * is_wifi() to check for 802.11 devices; are there any
   3167 		 * others?
   3168 		 */
   3169 		if (!is_wifi(sock_fd, device)) {
   3170 			/*
   3171 			 * It's not a Wi-Fi device; offer DOCSIS.
   3172 			 */
   3173 			handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
   3174 			/*
   3175 			 * If that fails, just leave the list empty.
   3176 			 */
   3177 			if (handle->dlt_list != NULL) {
   3178 				handle->dlt_list[0] = DLT_EN10MB;
   3179 				handle->dlt_list[1] = DLT_DOCSIS;
   3180 				handle->dlt_count = 2;
   3181 			}
   3182 		}
   3183 		/* FALLTHROUGH */
   3184 
   3185 	case ARPHRD_METRICOM:
   3186 	case ARPHRD_LOOPBACK:
   3187 		handle->linktype = DLT_EN10MB;
   3188 		handle->offset = 2;
   3189 		break;
   3190 
   3191 	case ARPHRD_EETHER:
   3192 		handle->linktype = DLT_EN3MB;
   3193 		break;
   3194 
   3195 	case ARPHRD_AX25:
   3196 		handle->linktype = DLT_AX25_KISS;
   3197 		break;
   3198 
   3199 	case ARPHRD_PRONET:
   3200 		handle->linktype = DLT_PRONET;
   3201 		break;
   3202 
   3203 	case ARPHRD_CHAOS:
   3204 		handle->linktype = DLT_CHAOS;
   3205 		break;
   3206 #ifndef ARPHRD_CAN
   3207 #define ARPHRD_CAN 280
   3208 #endif
   3209 	case ARPHRD_CAN:
   3210 		/*
   3211 		 * Map this to DLT_LINUX_SLL; that way, CAN frames will
   3212 		 * have ETH_P_CAN/LINUX_SLL_P_CAN as the protocol and
   3213 		 * CAN FD frames will have ETH_P_CANFD/LINUX_SLL_P_CANFD
   3214 		 * as the protocol, so they can be distinguished by the
   3215 		 * protocol in the SLL header.
   3216 		 */
   3217 		handle->linktype = DLT_LINUX_SLL;
   3218 		break;
   3219 
   3220 #ifndef ARPHRD_IEEE802_TR
   3221 #define ARPHRD_IEEE802_TR 800	/* From Linux 2.4 */
   3222 #endif
   3223 	case ARPHRD_IEEE802_TR:
   3224 	case ARPHRD_IEEE802:
   3225 		handle->linktype = DLT_IEEE802;
   3226 		handle->offset = 2;
   3227 		break;
   3228 
   3229 	case ARPHRD_ARCNET:
   3230 		handle->linktype = DLT_ARCNET_LINUX;
   3231 		break;
   3232 
   3233 #ifndef ARPHRD_FDDI	/* From Linux 2.2.13 */
   3234 #define ARPHRD_FDDI	774
   3235 #endif
   3236 	case ARPHRD_FDDI:
   3237 		handle->linktype = DLT_FDDI;
   3238 		handle->offset = 3;
   3239 		break;
   3240 
   3241 #ifndef ARPHRD_ATM  /* FIXME: How to #include this? */
   3242 #define ARPHRD_ATM 19
   3243 #endif
   3244 	case ARPHRD_ATM:
   3245 		/*
   3246 		 * The Classical IP implementation in ATM for Linux
   3247 		 * supports both what RFC 1483 calls "LLC Encapsulation",
   3248 		 * in which each packet has an LLC header, possibly
   3249 		 * with a SNAP header as well, prepended to it, and
   3250 		 * what RFC 1483 calls "VC Based Multiplexing", in which
   3251 		 * different virtual circuits carry different network
   3252 		 * layer protocols, and no header is prepended to packets.
   3253 		 *
   3254 		 * They both have an ARPHRD_ type of ARPHRD_ATM, so
   3255 		 * you can't use the ARPHRD_ type to find out whether
   3256 		 * captured packets will have an LLC header, and,
   3257 		 * while there's a socket ioctl to *set* the encapsulation
   3258 		 * type, there's no ioctl to *get* the encapsulation type.
   3259 		 *
   3260 		 * This means that
   3261 		 *
   3262 		 *	programs that dissect Linux Classical IP frames
   3263 		 *	would have to check for an LLC header and,
   3264 		 *	depending on whether they see one or not, dissect
   3265 		 *	the frame as LLC-encapsulated or as raw IP (I
   3266 		 *	don't know whether there's any traffic other than
   3267 		 *	IP that would show up on the socket, or whether
   3268 		 *	there's any support for IPv6 in the Linux
   3269 		 *	Classical IP code);
   3270 		 *
   3271 		 *	filter expressions would have to compile into
   3272 		 *	code that checks for an LLC header and does
   3273 		 *	the right thing.
   3274 		 *
   3275 		 * Both of those are a nuisance - and, at least on systems
   3276 		 * that support PF_PACKET sockets, we don't have to put
   3277 		 * up with those nuisances; instead, we can just capture
   3278 		 * in cooked mode.  That's what we'll do, if we can.
   3279 		 * Otherwise, we'll just fail.
   3280 		 */
   3281 		if (cooked_ok)
   3282 			handle->linktype = DLT_LINUX_SLL;
   3283 		else
   3284 			handle->linktype = -1;
   3285 		break;
   3286 
   3287 #ifndef ARPHRD_IEEE80211  /* From Linux 2.4.6 */
   3288 #define ARPHRD_IEEE80211 801
   3289 #endif
   3290 	case ARPHRD_IEEE80211:
   3291 		handle->linktype = DLT_IEEE802_11;
   3292 		break;
   3293 
   3294 #ifndef ARPHRD_IEEE80211_PRISM  /* From Linux 2.4.18 */
   3295 #define ARPHRD_IEEE80211_PRISM 802
   3296 #endif
   3297 	case ARPHRD_IEEE80211_PRISM:
   3298 		handle->linktype = DLT_PRISM_HEADER;
   3299 		break;
   3300 
   3301 #ifndef ARPHRD_IEEE80211_RADIOTAP /* new */
   3302 #define ARPHRD_IEEE80211_RADIOTAP 803
   3303 #endif
   3304 	case ARPHRD_IEEE80211_RADIOTAP:
   3305 		handle->linktype = DLT_IEEE802_11_RADIO;
   3306 		break;
   3307 
   3308 	case ARPHRD_PPP:
   3309 		/*
   3310 		 * Some PPP code in the kernel supplies no link-layer
   3311 		 * header whatsoever to PF_PACKET sockets; other PPP
   3312 		 * code supplies PPP link-layer headers ("syncppp.c");
   3313 		 * some PPP code might supply random link-layer
   3314 		 * headers (PPP over ISDN - there's code in Ethereal,
   3315 		 * for example, to cope with PPP-over-ISDN captures
   3316 		 * with which the Ethereal developers have had to cope,
   3317 		 * heuristically trying to determine which of the
   3318 		 * oddball link-layer headers particular packets have).
   3319 		 *
   3320 		 * As such, we just punt, and run all PPP interfaces
   3321 		 * in cooked mode, if we can; otherwise, we just treat
   3322 		 * it as DLT_RAW, for now - if somebody needs to capture,
   3323 		 * on a 2.0[.x] kernel, on PPP devices that supply a
   3324 		 * link-layer header, they'll have to add code here to
   3325 		 * map to the appropriate DLT_ type (possibly adding a
   3326 		 * new DLT_ type, if necessary).
   3327 		 */
   3328 		if (cooked_ok)
   3329 			handle->linktype = DLT_LINUX_SLL;
   3330 		else {
   3331 			/*
   3332 			 * XXX - handle ISDN types here?  We can't fall
   3333 			 * back on cooked sockets, so we'd have to
   3334 			 * figure out from the device name what type of
   3335 			 * link-layer encapsulation it's using, and map
   3336 			 * that to an appropriate DLT_ value, meaning
   3337 			 * we'd map "isdnN" devices to DLT_RAW (they
   3338 			 * supply raw IP packets with no link-layer
   3339 			 * header) and "isdY" devices to a new DLT_I4L_IP
   3340 			 * type that has only an Ethernet packet type as
   3341 			 * a link-layer header.
   3342 			 *
   3343 			 * But sometimes we seem to get random crap
   3344 			 * in the link-layer header when capturing on
   3345 			 * ISDN devices....
   3346 			 */
   3347 			handle->linktype = DLT_RAW;
   3348 		}
   3349 		break;
   3350 
   3351 #ifndef ARPHRD_CISCO
   3352 #define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */
   3353 #endif
   3354 	case ARPHRD_CISCO:
   3355 		handle->linktype = DLT_C_HDLC;
   3356 		break;
   3357 
   3358 	/* Not sure if this is correct for all tunnels, but it
   3359 	 * works for CIPE */
   3360 	case ARPHRD_TUNNEL:
   3361 #ifndef ARPHRD_SIT
   3362 #define ARPHRD_SIT 776	/* From Linux 2.2.13 */
   3363 #endif
   3364 	case ARPHRD_SIT:
   3365 	case ARPHRD_CSLIP:
   3366 	case ARPHRD_SLIP6:
   3367 	case ARPHRD_CSLIP6:
   3368 	case ARPHRD_ADAPT:
   3369 	case ARPHRD_SLIP:
   3370 #ifndef ARPHRD_RAWHDLC
   3371 #define ARPHRD_RAWHDLC 518
   3372 #endif
   3373 	case ARPHRD_RAWHDLC:
   3374 #ifndef ARPHRD_DLCI
   3375 #define ARPHRD_DLCI 15
   3376 #endif
   3377 	case ARPHRD_DLCI:
   3378 		/*
   3379 		 * XXX - should some of those be mapped to DLT_LINUX_SLL
   3380 		 * instead?  Should we just map all of them to DLT_LINUX_SLL?
   3381 		 */
   3382 		handle->linktype = DLT_RAW;
   3383 		break;
   3384 
   3385 #ifndef ARPHRD_FRAD
   3386 #define ARPHRD_FRAD 770
   3387 #endif
   3388 	case ARPHRD_FRAD:
   3389 		handle->linktype = DLT_FRELAY;
   3390 		break;
   3391 
   3392 	case ARPHRD_LOCALTLK:
   3393 		handle->linktype = DLT_LTALK;
   3394 		break;
   3395 
   3396 	case 18:
   3397 		/*
   3398 		 * RFC 4338 defines an encapsulation for IP and ARP
   3399 		 * packets that's compatible with the RFC 2625
   3400 		 * encapsulation, but that uses a different ARP
   3401 		 * hardware type and hardware addresses.  That
   3402 		 * ARP hardware type is 18; Linux doesn't define
   3403 		 * any ARPHRD_ value as 18, but if it ever officially
   3404 		 * supports RFC 4338-style IP-over-FC, it should define
   3405 		 * one.
   3406 		 *
   3407 		 * For now, we map it to DLT_IP_OVER_FC, in the hopes
   3408 		 * that this will encourage its use in the future,
   3409 		 * should Linux ever officially support RFC 4338-style
   3410 		 * IP-over-FC.
   3411 		 */
   3412 		handle->linktype = DLT_IP_OVER_FC;
   3413 		break;
   3414 
   3415 #ifndef ARPHRD_FCPP
   3416 #define ARPHRD_FCPP	784
   3417 #endif
   3418 	case ARPHRD_FCPP:
   3419 #ifndef ARPHRD_FCAL
   3420 #define ARPHRD_FCAL	785
   3421 #endif
   3422 	case ARPHRD_FCAL:
   3423 #ifndef ARPHRD_FCPL
   3424 #define ARPHRD_FCPL	786
   3425 #endif
   3426 	case ARPHRD_FCPL:
   3427 #ifndef ARPHRD_FCFABRIC
   3428 #define ARPHRD_FCFABRIC	787
   3429 #endif
   3430 	case ARPHRD_FCFABRIC:
   3431 		/*
   3432 		 * Back in 2002, Donald Lee at Cray wanted a DLT_ for
   3433 		 * IP-over-FC:
   3434 		 *
   3435 		 *	http://www.mail-archive.com/tcpdump-workers@sandelman.ottawa.on.ca/msg01043.html
   3436 		 *
   3437 		 * and one was assigned.
   3438 		 *
   3439 		 * In a later private discussion (spun off from a message
   3440 		 * on the ethereal-users list) on how to get that DLT_
   3441 		 * value in libpcap on Linux, I ended up deciding that
   3442 		 * the best thing to do would be to have him tweak the
   3443 		 * driver to set the ARPHRD_ value to some ARPHRD_FCxx
   3444 		 * type, and map all those types to DLT_IP_OVER_FC:
   3445 		 *
   3446 		 *	I've checked into the libpcap and tcpdump CVS tree
   3447 		 *	support for DLT_IP_OVER_FC.  In order to use that,
   3448 		 *	you'd have to modify your modified driver to return
   3449 		 *	one of the ARPHRD_FCxxx types, in "fcLINUXfcp.c" -
   3450 		 *	change it to set "dev->type" to ARPHRD_FCFABRIC, for
   3451 		 *	example (the exact value doesn't matter, it can be
   3452 		 *	any of ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL, or
   3453 		 *	ARPHRD_FCFABRIC).
   3454 		 *
   3455 		 * 11 years later, Christian Svensson wanted to map
   3456 		 * various ARPHRD_ values to DLT_FC_2 and
   3457 		 * DLT_FC_2_WITH_FRAME_DELIMS for raw Fibre Channel
   3458 		 * frames:
   3459 		 *
   3460 		 *	https://github.com/mcr/libpcap/pull/29
   3461 		 *
   3462 		 * There doesn't seem to be any network drivers that uses
   3463 		 * any of the ARPHRD_FC* values for IP-over-FC, and
   3464 		 * it's not exactly clear what the "Dummy types for non
   3465 		 * ARP hardware" are supposed to mean (link-layer
   3466 		 * header type?  Physical network type?), so it's
   3467 		 * not exactly clear why the ARPHRD_FC* types exist
   3468 		 * in the first place.
   3469 		 *
   3470 		 * For now, we map them to DLT_FC_2, and provide an
   3471 		 * option of DLT_FC_2_WITH_FRAME_DELIMS, as well as
   3472 		 * DLT_IP_OVER_FC just in case there's some old
   3473 		 * driver out there that uses one of those types for
   3474 		 * IP-over-FC on which somebody wants to capture
   3475 		 * packets.
   3476 		 */
   3477 		handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 3);
   3478 		/*
   3479 		 * If that fails, just leave the list empty.
   3480 		 */
   3481 		if (handle->dlt_list != NULL) {
   3482 			handle->dlt_list[0] = DLT_FC_2;
   3483 			handle->dlt_list[1] = DLT_FC_2_WITH_FRAME_DELIMS;
   3484 			handle->dlt_list[2] = DLT_IP_OVER_FC;
   3485 			handle->dlt_count = 3;
   3486 		}
   3487 		handle->linktype = DLT_FC_2;
   3488 		break;
   3489 
   3490 #ifndef ARPHRD_IRDA
   3491 #define ARPHRD_IRDA	783
   3492 #endif
   3493 	case ARPHRD_IRDA:
   3494 		/* Don't expect IP packet out of this interfaces... */
   3495 		handle->linktype = DLT_LINUX_IRDA;
   3496 		/* We need to save packet direction for IrDA decoding,
   3497 		 * so let's use "Linux-cooked" mode. Jean II
   3498 		 *
   3499 		 * XXX - this is handled in activate_new(). */
   3500 		/* handlep->cooked = 1; */
   3501 		break;
   3502 
   3503 	/* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation
   3504 	 * is needed, please report it to <daniele (at) orlandi.com> */
   3505 #ifndef ARPHRD_LAPD
   3506 #define ARPHRD_LAPD	8445
   3507 #endif
   3508 	case ARPHRD_LAPD:
   3509 		/* Don't expect IP packet out of this interfaces... */
   3510 		handle->linktype = DLT_LINUX_LAPD;
   3511 		break;
   3512 
   3513 #ifndef ARPHRD_NONE
   3514 #define ARPHRD_NONE	0xFFFE
   3515 #endif
   3516 	case ARPHRD_NONE:
   3517 		/*
   3518 		 * No link-layer header; packets are just IP
   3519 		 * packets, so use DLT_RAW.
   3520 		 */
   3521 		handle->linktype = DLT_RAW;
   3522 		break;
   3523 
   3524 #ifndef ARPHRD_IEEE802154
   3525 #define ARPHRD_IEEE802154      804
   3526 #endif
   3527        case ARPHRD_IEEE802154:
   3528                handle->linktype =  DLT_IEEE802_15_4_NOFCS;
   3529                break;
   3530 
   3531 #ifndef ARPHRD_NETLINK
   3532 #define ARPHRD_NETLINK	824
   3533 #endif
   3534 	case ARPHRD_NETLINK:
   3535 		handle->linktype = DLT_NETLINK;
   3536 		/*
   3537 		 * We need to use cooked mode, so that in sll_protocol we
   3538 		 * pick up the netlink protocol type such as NETLINK_ROUTE,
   3539 		 * NETLINK_GENERIC, NETLINK_FIB_LOOKUP, etc.
   3540 		 *
   3541 		 * XXX - this is handled in activate_new().
   3542 		 */
   3543 		/* handlep->cooked = 1; */
   3544 		break;
   3545 
   3546 #ifndef ARPHRD_VSOCKMON
   3547 #define ARPHRD_VSOCKMON	826
   3548 #endif
   3549 	case ARPHRD_VSOCKMON:
   3550 		handle->linktype = DLT_VSOCK;
   3551 		break;
   3552 
   3553 	default:
   3554 		handle->linktype = -1;
   3555 		break;
   3556 	}
   3557 }
   3558 
   3559 /* ===== Functions to interface to the newer kernels ================== */
   3560 
   3561 /*
   3562  * Try to open a packet socket using the new kernel PF_PACKET interface.
   3563  * Returns 1 on success, 0 on an error that means the new interface isn't
   3564  * present (so the old SOCK_PACKET interface should be tried), and a
   3565  * PCAP_ERROR_ value on an error that means that the old mechanism won't
   3566  * work either (so it shouldn't be tried).
   3567  */
   3568 static int
   3569 activate_new(pcap_t *handle)
   3570 {
   3571 #ifdef HAVE_PF_PACKET_SOCKETS
   3572 	struct pcap_linux *handlep = handle->priv;
   3573 	const char		*device = handle->opt.device;
   3574 	int			is_any_device = (strcmp(device, "any") == 0);
   3575 	int			protocol = pcap_protocol(handle);
   3576 	int			sock_fd = -1, arptype;
   3577 #ifdef HAVE_PACKET_AUXDATA
   3578 	int			val;
   3579 #endif
   3580 	int			err = 0;
   3581 	struct packet_mreq	mr;
   3582 #if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
   3583 	int			bpf_extensions;
   3584 	socklen_t		len = sizeof(bpf_extensions);
   3585 #endif
   3586 
   3587 	/*
   3588 	 * Open a socket with protocol family packet. If the
   3589 	 * "any" device was specified, we open a SOCK_DGRAM
   3590 	 * socket for the cooked interface, otherwise we first
   3591 	 * try a SOCK_RAW socket for the raw interface.
   3592 	 */
   3593 	sock_fd = is_any_device ?
   3594 		socket(PF_PACKET, SOCK_DGRAM, protocol) :
   3595 		socket(PF_PACKET, SOCK_RAW, protocol);
   3596 
   3597 	if (sock_fd == -1) {
   3598 		if (errno == EINVAL || errno == EAFNOSUPPORT) {
   3599 			/*
   3600 			 * We don't support PF_PACKET/SOCK_whatever
   3601 			 * sockets; try the old mechanism.
   3602 			 */
   3603 			return 0;
   3604 		}
   3605 
   3606 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   3607 		    errno, "socket");
   3608 		if (errno == EPERM || errno == EACCES) {
   3609 			/*
   3610 			 * You don't have permission to open the
   3611 			 * socket.
   3612 			 */
   3613 			return PCAP_ERROR_PERM_DENIED;
   3614 		} else {
   3615 			/*
   3616 			 * Other error.
   3617 			 */
   3618 			return PCAP_ERROR;
   3619 		}
   3620 	}
   3621 
   3622 	/* It seems the kernel supports the new interface. */
   3623 	handlep->sock_packet = 0;
   3624 
   3625 	/*
   3626 	 * Get the interface index of the loopback device.
   3627 	 * If the attempt fails, don't fail, just set the
   3628 	 * "handlep->lo_ifindex" to -1.
   3629 	 *
   3630 	 * XXX - can there be more than one device that loops
   3631 	 * packets back, i.e. devices other than "lo"?  If so,
   3632 	 * we'd need to find them all, and have an array of
   3633 	 * indices for them, and check all of them in
   3634 	 * "pcap_read_packet()".
   3635 	 */
   3636 	handlep->lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf);
   3637 
   3638 	/*
   3639 	 * Default value for offset to align link-layer payload
   3640 	 * on a 4-byte boundary.
   3641 	 */
   3642 	handle->offset	 = 0;
   3643 
   3644 	/*
   3645 	 * What kind of frames do we have to deal with? Fall back
   3646 	 * to cooked mode if we have an unknown interface type
   3647 	 * or a type we know doesn't work well in raw mode.
   3648 	 */
   3649 	if (!is_any_device) {
   3650 		/* Assume for now we don't need cooked mode. */
   3651 		handlep->cooked = 0;
   3652 
   3653 		if (handle->opt.rfmon) {
   3654 			/*
   3655 			 * We were asked to turn on monitor mode.
   3656 			 * Do so before we get the link-layer type,
   3657 			 * because entering monitor mode could change
   3658 			 * the link-layer type.
   3659 			 */
   3660 			err = enter_rfmon_mode(handle, sock_fd, device);
   3661 			if (err < 0) {
   3662 				/* Hard failure */
   3663 				close(sock_fd);
   3664 				return err;
   3665 			}
   3666 			if (err == 0) {
   3667 				/*
   3668 				 * Nothing worked for turning monitor mode
   3669 				 * on.
   3670 				 */
   3671 				close(sock_fd);
   3672 				return PCAP_ERROR_RFMON_NOTSUP;
   3673 			}
   3674 
   3675 			/*
   3676 			 * Either monitor mode has been turned on for
   3677 			 * the device, or we've been given a different
   3678 			 * device to open for monitor mode.  If we've
   3679 			 * been given a different device, use it.
   3680 			 */
   3681 			if (handlep->mondevice != NULL)
   3682 				device = handlep->mondevice;
   3683 		}
   3684 		arptype	= iface_get_arptype(sock_fd, device, handle->errbuf);
   3685 		if (arptype < 0) {
   3686 			close(sock_fd);
   3687 			return arptype;
   3688 		}
   3689 		map_arphrd_to_dlt(handle, sock_fd, arptype, device, 1);
   3690 		if (handle->linktype == -1 ||
   3691 		    handle->linktype == DLT_LINUX_SLL ||
   3692 		    handle->linktype == DLT_LINUX_IRDA ||
   3693 		    handle->linktype == DLT_LINUX_LAPD ||
   3694 		    handle->linktype == DLT_NETLINK ||
   3695 		    (handle->linktype == DLT_EN10MB &&
   3696 		     (strncmp("isdn", device, 4) == 0 ||
   3697 		      strncmp("isdY", device, 4) == 0))) {
   3698 			/*
   3699 			 * Unknown interface type (-1), or a
   3700 			 * device we explicitly chose to run
   3701 			 * in cooked mode (e.g., PPP devices),
   3702 			 * or an ISDN device (whose link-layer
   3703 			 * type we can only determine by using
   3704 			 * APIs that may be different on different
   3705 			 * kernels) - reopen in cooked mode.
   3706 			 */
   3707 			if (close(sock_fd) == -1) {
   3708 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   3709 				    PCAP_ERRBUF_SIZE, errno, "close");
   3710 				return PCAP_ERROR;
   3711 			}
   3712 			sock_fd = socket(PF_PACKET, SOCK_DGRAM, protocol);
   3713 			if (sock_fd == -1) {
   3714 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   3715 				    PCAP_ERRBUF_SIZE, errno, "socket");
   3716 				if (errno == EPERM || errno == EACCES) {
   3717 					/*
   3718 					 * You don't have permission to
   3719 					 * open the socket.
   3720 					 */
   3721 					return PCAP_ERROR_PERM_DENIED;
   3722 				} else {
   3723 					/*
   3724 					 * Other error.
   3725 					 */
   3726 					return PCAP_ERROR;
   3727 				}
   3728 			}
   3729 			handlep->cooked = 1;
   3730 
   3731 			/*
   3732 			 * Get rid of any link-layer type list
   3733 			 * we allocated - this only supports cooked
   3734 			 * capture.
   3735 			 */
   3736 			if (handle->dlt_list != NULL) {
   3737 				free(handle->dlt_list);
   3738 				handle->dlt_list = NULL;
   3739 				handle->dlt_count = 0;
   3740 			}
   3741 
   3742 			if (handle->linktype == -1) {
   3743 				/*
   3744 				 * Warn that we're falling back on
   3745 				 * cooked mode; we may want to
   3746 				 * update "map_arphrd_to_dlt()"
   3747 				 * to handle the new type.
   3748 				 */
   3749 				pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   3750 					"arptype %d not "
   3751 					"supported by libpcap - "
   3752 					"falling back to cooked "
   3753 					"socket",
   3754 					arptype);
   3755 			}
   3756 
   3757 			/*
   3758 			 * IrDA capture is not a real "cooked" capture,
   3759 			 * it's IrLAP frames, not IP packets.  The
   3760 			 * same applies to LAPD capture.
   3761 			 */
   3762 			if (handle->linktype != DLT_LINUX_IRDA &&
   3763 			    handle->linktype != DLT_LINUX_LAPD &&
   3764 			    handle->linktype != DLT_NETLINK)
   3765 				handle->linktype = DLT_LINUX_SLL;
   3766 		}
   3767 
   3768 		handlep->ifindex = iface_get_id(sock_fd, device,
   3769 		    handle->errbuf);
   3770 		if (handlep->ifindex == -1) {
   3771 			close(sock_fd);
   3772 			return PCAP_ERROR;
   3773 		}
   3774 
   3775 		if ((err = iface_bind(sock_fd, handlep->ifindex,
   3776 		    handle->errbuf, protocol)) != 1) {
   3777 		    	close(sock_fd);
   3778 			if (err < 0)
   3779 				return err;
   3780 			else
   3781 				return 0;	/* try old mechanism */
   3782 		}
   3783 	} else {
   3784 		/*
   3785 		 * The "any" device.
   3786 		 */
   3787 		if (handle->opt.rfmon) {
   3788 			/*
   3789 			 * It doesn't support monitor mode.
   3790 			 */
   3791 			close(sock_fd);
   3792 			return PCAP_ERROR_RFMON_NOTSUP;
   3793 		}
   3794 
   3795 		/*
   3796 		 * It uses cooked mode.
   3797 		 */
   3798 		handlep->cooked = 1;
   3799 		handle->linktype = DLT_LINUX_SLL;
   3800 
   3801 		/*
   3802 		 * We're not bound to a device.
   3803 		 * For now, we're using this as an indication
   3804 		 * that we can't transmit; stop doing that only
   3805 		 * if we figure out how to transmit in cooked
   3806 		 * mode.
   3807 		 */
   3808 		handlep->ifindex = -1;
   3809 	}
   3810 
   3811 	/*
   3812 	 * Select promiscuous mode on if "promisc" is set.
   3813 	 *
   3814 	 * Do not turn allmulti mode on if we don't select
   3815 	 * promiscuous mode - on some devices (e.g., Orinoco
   3816 	 * wireless interfaces), allmulti mode isn't supported
   3817 	 * and the driver implements it by turning promiscuous
   3818 	 * mode on, and that screws up the operation of the
   3819 	 * card as a normal networking interface, and on no
   3820 	 * other platform I know of does starting a non-
   3821 	 * promiscuous capture affect which multicast packets
   3822 	 * are received by the interface.
   3823 	 */
   3824 
   3825 	/*
   3826 	 * Hmm, how can we set promiscuous mode on all interfaces?
   3827 	 * I am not sure if that is possible at all.  For now, we
   3828 	 * silently ignore attempts to turn promiscuous mode on
   3829 	 * for the "any" device (so you don't have to explicitly
   3830 	 * disable it in programs such as tcpdump).
   3831 	 */
   3832 
   3833 	if (!is_any_device && handle->opt.promisc) {
   3834 		memset(&mr, 0, sizeof(mr));
   3835 		mr.mr_ifindex = handlep->ifindex;
   3836 		mr.mr_type    = PACKET_MR_PROMISC;
   3837 		if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
   3838 		    &mr, sizeof(mr)) == -1) {
   3839 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   3840 			    PCAP_ERRBUF_SIZE, errno, "setsockopt");
   3841 			close(sock_fd);
   3842 			return PCAP_ERROR;
   3843 		}
   3844 	}
   3845 
   3846 	/* Enable auxillary data if supported and reserve room for
   3847 	 * reconstructing VLAN headers. */
   3848 #ifdef HAVE_PACKET_AUXDATA
   3849 	val = 1;
   3850 	if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
   3851 		       sizeof(val)) == -1 && errno != ENOPROTOOPT) {
   3852 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   3853 		    errno, "setsockopt");
   3854 		close(sock_fd);
   3855 		return PCAP_ERROR;
   3856 	}
   3857 	handle->offset += VLAN_TAG_LEN;
   3858 #endif /* HAVE_PACKET_AUXDATA */
   3859 
   3860 	/*
   3861 	 * This is a 2.2[.x] or later kernel (we know that
   3862 	 * because we're not using a SOCK_PACKET socket -
   3863 	 * PF_PACKET is supported only in 2.2 and later
   3864 	 * kernels).
   3865 	 *
   3866 	 * We can safely pass "recvfrom()" a byte count
   3867 	 * based on the snapshot length.
   3868 	 *
   3869 	 * If we're in cooked mode, make the snapshot length
   3870 	 * large enough to hold a "cooked mode" header plus
   3871 	 * 1 byte of packet data (so we don't pass a byte
   3872 	 * count of 0 to "recvfrom()").
   3873 	 */
   3874 	if (handlep->cooked) {
   3875 		if (handle->snapshot < SLL_HDR_LEN + 1)
   3876 			handle->snapshot = SLL_HDR_LEN + 1;
   3877 	}
   3878 	handle->bufsize = handle->snapshot;
   3879 
   3880 	/*
   3881 	 * Set the offset at which to insert VLAN tags.
   3882 	 * That should be the offset of the type field.
   3883 	 */
   3884 	switch (handle->linktype) {
   3885 
   3886 	case DLT_EN10MB:
   3887 		/*
   3888 		 * The type field is after the destination and source
   3889 		 * MAC address.
   3890 		 */
   3891 		handlep->vlan_offset = 2 * ETH_ALEN;
   3892 		break;
   3893 
   3894 	case DLT_LINUX_SLL:
   3895 		/*
   3896 		 * The type field is in the last 2 bytes of the
   3897 		 * DLT_LINUX_SLL header.
   3898 		 */
   3899 		handlep->vlan_offset = SLL_HDR_LEN - 2;
   3900 		break;
   3901 
   3902 	default:
   3903 		handlep->vlan_offset = -1; /* unknown */
   3904 		break;
   3905 	}
   3906 
   3907 #if defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS)
   3908 	if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
   3909 		int nsec_tstamps = 1;
   3910 
   3911 		if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMPNS, &nsec_tstamps, sizeof(nsec_tstamps)) < 0) {
   3912 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "setsockopt: unable to set SO_TIMESTAMPNS");
   3913 			close(sock_fd);
   3914 			return PCAP_ERROR;
   3915 		}
   3916 	}
   3917 #endif /* defined(SIOCGSTAMPNS) && defined(SO_TIMESTAMPNS) */
   3918 
   3919 	/*
   3920 	 * We've succeeded. Save the socket FD in the pcap structure.
   3921 	 */
   3922 	handle->fd = sock_fd;
   3923 
   3924 #if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
   3925 	/*
   3926 	 * Can we generate special code for VLAN checks?
   3927 	 * (XXX - what if we need the special code but it's not supported
   3928 	 * by the OS?  Is that possible?)
   3929 	 */
   3930 	if (getsockopt(sock_fd, SOL_SOCKET, SO_BPF_EXTENSIONS,
   3931 	    &bpf_extensions, &len) == 0) {
   3932 		if (bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT) {
   3933 			/*
   3934 			 * Yes, we can.  Request that we do so.
   3935 			 */
   3936 			handle->bpf_codegen_flags |= BPF_SPECIAL_VLAN_HANDLING;
   3937 		}
   3938 	}
   3939 #endif /* defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT) */
   3940 
   3941 	return 1;
   3942 #else /* HAVE_PF_PACKET_SOCKETS */
   3943 	strlcpy(ebuf,
   3944 		"New packet capturing interface not supported by build "
   3945 		"environment", PCAP_ERRBUF_SIZE);
   3946 	return 0;
   3947 #endif /* HAVE_PF_PACKET_SOCKETS */
   3948 }
   3949 
   3950 #ifdef HAVE_PACKET_RING
   3951 /*
   3952  * Attempt to activate with memory-mapped access.
   3953  *
   3954  * On success, returns 1, and sets *status to 0 if there are no warnings
   3955  * or to a PCAP_WARNING_ code if there is a warning.
   3956  *
   3957  * On failure due to lack of support for memory-mapped capture, returns
   3958  * 0.
   3959  *
   3960  * On error, returns -1, and sets *status to the appropriate error code;
   3961  * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
   3962  */
   3963 static int
   3964 activate_mmap(pcap_t *handle, int *status)
   3965 {
   3966 	struct pcap_linux *handlep = handle->priv;
   3967 	int ret;
   3968 
   3969 	/*
   3970 	 * Attempt to allocate a buffer to hold the contents of one
   3971 	 * packet, for use by the oneshot callback.
   3972 	 */
   3973 	handlep->oneshot_buffer = malloc(handle->snapshot);
   3974 	if (handlep->oneshot_buffer == NULL) {
   3975 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   3976 		    errno, "can't allocate oneshot buffer");
   3977 		*status = PCAP_ERROR;
   3978 		return -1;
   3979 	}
   3980 
   3981 	if (handle->opt.buffer_size == 0) {
   3982 		/* by default request 2M for the ring buffer */
   3983 		handle->opt.buffer_size = 2*1024*1024;
   3984 	}
   3985 	ret = prepare_tpacket_socket(handle);
   3986 	if (ret == -1) {
   3987 		free(handlep->oneshot_buffer);
   3988 		*status = PCAP_ERROR;
   3989 		return ret;
   3990 	}
   3991 	ret = create_ring(handle, status);
   3992 	if (ret == 0) {
   3993 		/*
   3994 		 * We don't support memory-mapped capture; our caller
   3995 		 * will fall back on reading from the socket.
   3996 		 */
   3997 		free(handlep->oneshot_buffer);
   3998 		return 0;
   3999 	}
   4000 	if (ret == -1) {
   4001 		/*
   4002 		 * Error attempting to enable memory-mapped capture;
   4003 		 * fail.  create_ring() has set *status.
   4004 		 */
   4005 		free(handlep->oneshot_buffer);
   4006 		return -1;
   4007 	}
   4008 
   4009 	/*
   4010 	 * Success.  *status has been set either to 0 if there are no
   4011 	 * warnings or to a PCAP_WARNING_ value if there is a warning.
   4012 	 *
   4013 	 * Override some defaults and inherit the other fields from
   4014 	 * activate_new.
   4015 	 * handle->offset is used to get the current position into the rx ring.
   4016 	 * handle->cc is used to store the ring size.
   4017 	 */
   4018 
   4019 	switch (handlep->tp_version) {
   4020 	case TPACKET_V1:
   4021 		handle->read_op = pcap_read_linux_mmap_v1;
   4022 		break;
   4023 	case TPACKET_V1_64:
   4024 		handle->read_op = pcap_read_linux_mmap_v1_64;
   4025 		break;
   4026 #ifdef HAVE_TPACKET2
   4027 	case TPACKET_V2:
   4028 		handle->read_op = pcap_read_linux_mmap_v2;
   4029 		break;
   4030 #endif
   4031 #ifdef HAVE_TPACKET3
   4032 	case TPACKET_V3:
   4033 		handle->read_op = pcap_read_linux_mmap_v3;
   4034 		break;
   4035 #endif
   4036 	}
   4037 	handle->cleanup_op = pcap_cleanup_linux_mmap;
   4038 	handle->setfilter_op = pcap_setfilter_linux_mmap;
   4039 	handle->setnonblock_op = pcap_setnonblock_mmap;
   4040 	handle->getnonblock_op = pcap_getnonblock_mmap;
   4041 	handle->oneshot_callback = pcap_oneshot_mmap;
   4042 	handle->selectable_fd = handle->fd;
   4043 	return 1;
   4044 }
   4045 #else /* HAVE_PACKET_RING */
   4046 static int
   4047 activate_mmap(pcap_t *handle _U_, int *status _U_)
   4048 {
   4049 	return 0;
   4050 }
   4051 #endif /* HAVE_PACKET_RING */
   4052 
   4053 #ifdef HAVE_PACKET_RING
   4054 
   4055 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
   4056 /*
   4057  * Attempt to set the socket to the specified version of the memory-mapped
   4058  * header.
   4059  *
   4060  * Return 0 if we succeed; return 1 if we fail because that version isn't
   4061  * supported; return -1 on any other error, and set handle->errbuf.
   4062  */
   4063 static int
   4064 init_tpacket(pcap_t *handle, int version, const char *version_str)
   4065 {
   4066 	struct pcap_linux *handlep = handle->priv;
   4067 	int val = version;
   4068 	socklen_t len = sizeof(val);
   4069 
   4070 	/*
   4071 	 * Probe whether kernel supports the specified TPACKET version;
   4072 	 * this also gets the length of the header for that version.
   4073 	 */
   4074 	if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
   4075 		if (errno == ENOPROTOOPT || errno == EINVAL)
   4076 			return 1;	/* no */
   4077 
   4078 		/* Failed to even find out; this is a fatal error. */
   4079 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4080 		    errno, "can't get %s header len on packet socket",
   4081 		    version_str);
   4082 		return -1;
   4083 	}
   4084 	handlep->tp_hdrlen = val;
   4085 
   4086 	val = version;
   4087 	if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
   4088 			   sizeof(val)) < 0) {
   4089 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4090 		    errno, "can't activate %s on packet socket", version_str);
   4091 		return -1;
   4092 	}
   4093 	handlep->tp_version = version;
   4094 
   4095 	/* Reserve space for VLAN tag reconstruction */
   4096 	val = VLAN_TAG_LEN;
   4097 	if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val,
   4098 			   sizeof(val)) < 0) {
   4099 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4100 		    errno, "can't set up reserve on packet socket");
   4101 		return -1;
   4102 	}
   4103 
   4104 	return 0;
   4105 }
   4106 #endif /* defined HAVE_TPACKET2 || defined HAVE_TPACKET3 */
   4107 
   4108 /*
   4109  * If the instruction set for which we're compiling has both 32-bit
   4110  * and 64-bit versions, and Linux support for the 64-bit version
   4111  * predates TPACKET_V2, define ISA_64_BIT as the .machine value
   4112  * you get from uname() for the 64-bit version.  Otherwise, leave
   4113  * it undefined.  (This includes ARM, which has a 64-bit version,
   4114  * but Linux support for it appeared well after TPACKET_V2 support
   4115  * did, so there should never be a case where 32-bit ARM code is
   4116  * running o a 64-bit kernel that only supports TPACKET_V1.)
   4117  *
   4118  * If we've omitted your favorite such architecture, please contribute
   4119  * a patch.  (No patch is needed for architectures that are 32-bit-only
   4120  * or for which Linux has no support for 32-bit userland - or for which,
   4121  * as noted, 64-bit support appeared in Linux after TPACKET_V2 support
   4122  * did.)
   4123  */
   4124 #if defined(__i386__)
   4125 #define ISA_64_BIT	"x86_64"
   4126 #elif defined(__ppc__)
   4127 #define ISA_64_BIT	"ppc64"
   4128 #elif defined(__sparc__)
   4129 #define ISA_64_BIT	"sparc64"
   4130 #elif defined(__s390__)
   4131 #define ISA_64_BIT	"s390x"
   4132 #elif defined(__mips__)
   4133 #define ISA_64_BIT	"mips64"
   4134 #elif defined(__hppa__)
   4135 #define ISA_64_BIT	"parisc64"
   4136 #endif
   4137 
   4138 /*
   4139  * Attempt to set the socket to version 3 of the memory-mapped header and,
   4140  * if that fails because version 3 isn't supported, attempt to fall
   4141  * back to version 2.  If version 2 isn't supported, just leave it at
   4142  * version 1.
   4143  *
   4144  * Return 1 if we succeed or if we fail because neither version 2 nor 3 is
   4145  * supported; return -1 on any other error, and set handle->errbuf.
   4146  */
   4147 static int
   4148 prepare_tpacket_socket(pcap_t *handle)
   4149 {
   4150 	struct pcap_linux *handlep = handle->priv;
   4151 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
   4152 	int ret;
   4153 #endif
   4154 
   4155 #ifdef HAVE_TPACKET3
   4156 	/*
   4157 	 * Try setting the version to TPACKET_V3.
   4158 	 *
   4159 	 * The only mode in which buffering is done on PF_PACKET
   4160 	 * sockets, so that packets might not be delivered
   4161 	 * immediately, is TPACKET_V3 mode.
   4162 	 *
   4163 	 * The buffering cannot be disabled in that mode, so
   4164 	 * if the user has requested immediate mode, we don't
   4165 	 * use TPACKET_V3.
   4166 	 */
   4167 	if (!handle->opt.immediate) {
   4168 		ret = init_tpacket(handle, TPACKET_V3, "TPACKET_V3");
   4169 		if (ret == 0) {
   4170 			/*
   4171 			 * Success.
   4172 			 */
   4173 			return 1;
   4174 		}
   4175 		if (ret == -1) {
   4176 			/*
   4177 			 * We failed for some reason other than "the
   4178 			 * kernel doesn't support TPACKET_V3".
   4179 			 */
   4180 			return -1;
   4181 		}
   4182 	}
   4183 #endif /* HAVE_TPACKET3 */
   4184 
   4185 #ifdef HAVE_TPACKET2
   4186 	/*
   4187 	 * Try setting the version to TPACKET_V2.
   4188 	 */
   4189 	ret = init_tpacket(handle, TPACKET_V2, "TPACKET_V2");
   4190 	if (ret == 0) {
   4191 		/*
   4192 		 * Success.
   4193 		 */
   4194 		return 1;
   4195 	}
   4196 	if (ret == -1) {
   4197 		/*
   4198 		 * We failed for some reason other than "the
   4199 		 * kernel doesn't support TPACKET_V2".
   4200 		 */
   4201 		return -1;
   4202 	}
   4203 #endif /* HAVE_TPACKET2 */
   4204 
   4205 	/*
   4206 	 * OK, we're using TPACKET_V1, as that's all the kernel supports.
   4207 	 */
   4208 	handlep->tp_version = TPACKET_V1;
   4209 	handlep->tp_hdrlen = sizeof(struct tpacket_hdr);
   4210 
   4211 #ifdef ISA_64_BIT
   4212 	/*
   4213 	 * 32-bit userspace + 64-bit kernel + TPACKET_V1 are not compatible with
   4214 	 * each other due to platform-dependent data type size differences.
   4215 	 *
   4216 	 * If we have a 32-bit userland and a 64-bit kernel, use an
   4217 	 * internally-defined TPACKET_V1_64, with which we use a 64-bit
   4218 	 * version of the data structures.
   4219 	 */
   4220 	if (sizeof(long) == 4) {
   4221 		/*
   4222 		 * This is 32-bit code.
   4223 		 */
   4224 		struct utsname utsname;
   4225 
   4226 		if (uname(&utsname) == -1) {
   4227 			/*
   4228 			 * Failed.
   4229 			 */
   4230 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   4231 			    PCAP_ERRBUF_SIZE, errno, "uname failed");
   4232 			return -1;
   4233 		}
   4234 		if (strcmp(utsname.machine, ISA_64_BIT) == 0) {
   4235 			/*
   4236 			 * uname() tells us the machine is 64-bit,
   4237 			 * so we presumably have a 64-bit kernel.
   4238 			 *
   4239 			 * XXX - this presumes that uname() won't lie
   4240 			 * in 32-bit code and claim that the machine
   4241 			 * has the 32-bit version of the ISA.
   4242 			 */
   4243 			handlep->tp_version = TPACKET_V1_64;
   4244 			handlep->tp_hdrlen = sizeof(struct tpacket_hdr_64);
   4245 		}
   4246 	}
   4247 #endif
   4248 
   4249 	return 1;
   4250 }
   4251 
   4252 #define MAX(a,b) ((a)>(b)?(a):(b))
   4253 
   4254 /*
   4255  * Attempt to set up memory-mapped access.
   4256  *
   4257  * On success, returns 1, and sets *status to 0 if there are no warnings
   4258  * or to a PCAP_WARNING_ code if there is a warning.
   4259  *
   4260  * On failure due to lack of support for memory-mapped capture, returns
   4261  * 0.
   4262  *
   4263  * On error, returns -1, and sets *status to the appropriate error code;
   4264  * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
   4265  */
   4266 static int
   4267 create_ring(pcap_t *handle, int *status)
   4268 {
   4269 	struct pcap_linux *handlep = handle->priv;
   4270 	unsigned i, j, frames_per_block;
   4271 #ifdef HAVE_TPACKET3
   4272 	/*
   4273 	 * For sockets using TPACKET_V1 or TPACKET_V2, the extra
   4274 	 * stuff at the end of a struct tpacket_req3 will be
   4275 	 * ignored, so this is OK even for those sockets.
   4276 	 */
   4277 	struct tpacket_req3 req;
   4278 #else
   4279 	struct tpacket_req req;
   4280 #endif
   4281 	socklen_t len;
   4282 	unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff;
   4283 	unsigned int frame_size;
   4284 
   4285 	/*
   4286 	 * Start out assuming no warnings or errors.
   4287 	 */
   4288 	*status = 0;
   4289 
   4290 	switch (handlep->tp_version) {
   4291 
   4292 	case TPACKET_V1:
   4293 	case TPACKET_V1_64:
   4294 #ifdef HAVE_TPACKET2
   4295 	case TPACKET_V2:
   4296 #endif
   4297 		/* Note that with large snapshot length (say 256K, which is
   4298 		 * the default for recent versions of tcpdump, Wireshark,
   4299 		 * TShark, dumpcap or 64K, the value that "-s 0" has given for
   4300 		 * a long time with tcpdump), if we use the snapshot
   4301 		 * length to calculate the frame length, only a few frames
   4302 		 * will be available in the ring even with pretty
   4303 		 * large ring size (and a lot of memory will be unused).
   4304 		 *
   4305 		 * Ideally, we should choose a frame length based on the
   4306 		 * minimum of the specified snapshot length and the maximum
   4307 		 * packet size.  That's not as easy as it sounds; consider,
   4308 		 * for example, an 802.11 interface in monitor mode, where
   4309 		 * the frame would include a radiotap header, where the
   4310 		 * maximum radiotap header length is device-dependent.
   4311 		 *
   4312 		 * So, for now, we just do this for Ethernet devices, where
   4313 		 * there's no metadata header, and the link-layer header is
   4314 		 * fixed length.  We can get the maximum packet size by
   4315 		 * adding 18, the Ethernet header length plus the CRC length
   4316 		 * (just in case we happen to get the CRC in the packet), to
   4317 		 * the MTU of the interface; we fetch the MTU in the hopes
   4318 		 * that it reflects support for jumbo frames.  (Even if the
   4319 		 * interface is just being used for passive snooping, the
   4320 		 * driver might set the size of buffers in the receive ring
   4321 		 * based on the MTU, so that the MTU limits the maximum size
   4322 		 * of packets that we can receive.)
   4323 		 *
   4324 		 * If segmentation/fragmentation or receive offload are
   4325 		 * enabled, we can get reassembled/aggregated packets larger
   4326 		 * than MTU, but bounded to 65535 plus the Ethernet overhead,
   4327 		 * due to kernel and protocol constraints */
   4328 		frame_size = handle->snapshot;
   4329 		if (handle->linktype == DLT_EN10MB) {
   4330 			unsigned int max_frame_len;
   4331 			int mtu;
   4332 			int offload;
   4333 
   4334 			mtu = iface_get_mtu(handle->fd, handle->opt.device,
   4335 			    handle->errbuf);
   4336 			if (mtu == -1) {
   4337 				*status = PCAP_ERROR;
   4338 				return -1;
   4339 			}
   4340 			offload = iface_get_offload(handle);
   4341 			if (offload == -1) {
   4342 				*status = PCAP_ERROR;
   4343 				return -1;
   4344 			}
   4345 			if (offload)
   4346 				max_frame_len = MAX(mtu, 65535);
   4347 			else
   4348 				max_frame_len = mtu;
   4349 			max_frame_len += 18;
   4350 
   4351 			if (frame_size > max_frame_len)
   4352 				frame_size = max_frame_len;
   4353 		}
   4354 
   4355 		/* NOTE: calculus matching those in tpacket_rcv()
   4356 		 * in linux-2.6/net/packet/af_packet.c
   4357 		 */
   4358 		len = sizeof(sk_type);
   4359 		if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type,
   4360 		    &len) < 0) {
   4361 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   4362 			    PCAP_ERRBUF_SIZE, errno, "getsockopt");
   4363 			*status = PCAP_ERROR;
   4364 			return -1;
   4365 		}
   4366 #ifdef PACKET_RESERVE
   4367 		len = sizeof(tp_reserve);
   4368 		if (getsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE,
   4369 		    &tp_reserve, &len) < 0) {
   4370 			if (errno != ENOPROTOOPT) {
   4371 				/*
   4372 				 * ENOPROTOOPT means "kernel doesn't support
   4373 				 * PACKET_RESERVE", in which case we fall back
   4374 				 * as best we can.
   4375 				 */
   4376 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   4377 				    PCAP_ERRBUF_SIZE, errno, "getsockopt");
   4378 				*status = PCAP_ERROR;
   4379 				return -1;
   4380 			}
   4381 			tp_reserve = 0;	/* older kernel, reserve not supported */
   4382 		}
   4383 #else
   4384 		tp_reserve = 0;	/* older kernel, reserve not supported */
   4385 #endif
   4386 		maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE;
   4387 			/* XXX: in the kernel maclen is calculated from
   4388 			 * LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len
   4389 			 * in:  packet_snd()           in linux-2.6/net/packet/af_packet.c
   4390 			 * then packet_alloc_skb()     in linux-2.6/net/packet/af_packet.c
   4391 			 * then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c
   4392 			 * but I see no way to get those sizes in userspace,
   4393 			 * like for instance with an ifreq ioctl();
   4394 			 * the best thing I've found so far is MAX_HEADER in
   4395 			 * the kernel part of linux-2.6/include/linux/netdevice.h
   4396 			 * which goes up to 128+48=176; since pcap-linux.c
   4397 			 * defines a MAX_LINKHEADER_SIZE of 256 which is
   4398 			 * greater than that, let's use it.. maybe is it even
   4399 			 * large enough to directly replace macoff..
   4400 			 */
   4401 		tp_hdrlen = TPACKET_ALIGN(handlep->tp_hdrlen) + sizeof(struct sockaddr_ll) ;
   4402 		netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve;
   4403 			/* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN
   4404 			 * of netoff, which contradicts
   4405 			 * linux-2.6/Documentation/networking/packet_mmap.txt
   4406 			 * documenting that:
   4407 			 * "- Gap, chosen so that packet data (Start+tp_net)
   4408 			 * aligns to TPACKET_ALIGNMENT=16"
   4409 			 */
   4410 			/* NOTE: in linux-2.6/include/linux/skbuff.h:
   4411 			 * "CPUs often take a performance hit
   4412 			 *  when accessing unaligned memory locations"
   4413 			 */
   4414 		macoff = netoff - maclen;
   4415 		req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size);
   4416 		/*
   4417 		 * Round the buffer size up to a multiple of the
   4418 		 * frame size (rather than rounding down, which
   4419 		 * would give a buffer smaller than our caller asked
   4420 		 * for, and possibly give zero frames if the requested
   4421 		 * buffer size is too small for one frame).
   4422 		 */
   4423 		req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
   4424 		break;
   4425 
   4426 #ifdef HAVE_TPACKET3
   4427 	case TPACKET_V3:
   4428 		/* The "frames" for this are actually buffers that
   4429 		 * contain multiple variable-sized frames.
   4430 		 *
   4431 		 * We pick a "frame" size of MAXIMUM_SNAPLEN to leave
   4432 		 * enough room for at least one reasonably-sized packet
   4433 		 * in the "frame". */
   4434 		req.tp_frame_size = MAXIMUM_SNAPLEN;
   4435 		/*
   4436 		 * Round the buffer size up to a multiple of the
   4437 		 * "frame" size (rather than rounding down, which
   4438 		 * would give a buffer smaller than our caller asked
   4439 		 * for, and possibly give zero "frames" if the requested
   4440 		 * buffer size is too small for one "frame").
   4441 		 */
   4442 		req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
   4443 		break;
   4444 #endif
   4445 	default:
   4446 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   4447 		    "Internal error: unknown TPACKET_ value %u",
   4448 		    handlep->tp_version);
   4449 		*status = PCAP_ERROR;
   4450 		return -1;
   4451 	}
   4452 
   4453 	/* compute the minumum block size that will handle this frame.
   4454 	 * The block has to be page size aligned.
   4455 	 * The max block size allowed by the kernel is arch-dependent and
   4456 	 * it's not explicitly checked here. */
   4457 	req.tp_block_size = getpagesize();
   4458 	while (req.tp_block_size < req.tp_frame_size)
   4459 		req.tp_block_size <<= 1;
   4460 
   4461 	frames_per_block = req.tp_block_size/req.tp_frame_size;
   4462 
   4463 	/*
   4464 	 * PACKET_TIMESTAMP was added after linux/net_tstamp.h was,
   4465 	 * so we check for PACKET_TIMESTAMP.  We check for
   4466 	 * linux/net_tstamp.h just in case a system somehow has
   4467 	 * PACKET_TIMESTAMP but not linux/net_tstamp.h; that might
   4468 	 * be unnecessary.
   4469 	 *
   4470 	 * SIOCSHWTSTAMP was introduced in the patch that introduced
   4471 	 * linux/net_tstamp.h, so we don't bother checking whether
   4472 	 * SIOCSHWTSTAMP is defined (if your Linux system has
   4473 	 * linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your
   4474 	 * Linux system is badly broken).
   4475 	 */
   4476 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
   4477 	/*
   4478 	 * If we were told to do so, ask the kernel and the driver
   4479 	 * to use hardware timestamps.
   4480 	 *
   4481 	 * Hardware timestamps are only supported with mmapped
   4482 	 * captures.
   4483 	 */
   4484 	if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER ||
   4485 	    handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) {
   4486 		struct hwtstamp_config hwconfig;
   4487 		struct ifreq ifr;
   4488 		int timesource;
   4489 
   4490 		/*
   4491 		 * Ask for hardware time stamps on all packets,
   4492 		 * including transmitted packets.
   4493 		 */
   4494 		memset(&hwconfig, 0, sizeof(hwconfig));
   4495 		hwconfig.tx_type = HWTSTAMP_TX_ON;
   4496 		hwconfig.rx_filter = HWTSTAMP_FILTER_ALL;
   4497 
   4498 		memset(&ifr, 0, sizeof(ifr));
   4499 		strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
   4500 		ifr.ifr_data = (void *)&hwconfig;
   4501 
   4502 		if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) {
   4503 			switch (errno) {
   4504 
   4505 			case EPERM:
   4506 				/*
   4507 				 * Treat this as an error, as the
   4508 				 * user should try to run this
   4509 				 * with the appropriate privileges -
   4510 				 * and, if they can't, shouldn't
   4511 				 * try requesting hardware time stamps.
   4512 				 */
   4513 				*status = PCAP_ERROR_PERM_DENIED;
   4514 				return -1;
   4515 
   4516 			case EOPNOTSUPP:
   4517 			case ERANGE:
   4518 				/*
   4519 				 * Treat this as a warning, as the
   4520 				 * only way to fix the warning is to
   4521 				 * get an adapter that supports hardware
   4522 				 * time stamps for *all* packets.
   4523 				 * (ERANGE means "we support hardware
   4524 				 * time stamps, but for packets matching
   4525 				 * that particular filter", so it means
   4526 				 * "we don't support hardware time stamps
   4527 				 * for all incoming packets" here.)
   4528 				 *
   4529 				 * We'll just fall back on the standard
   4530 				 * host time stamps.
   4531 				 */
   4532 				*status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
   4533 				break;
   4534 
   4535 			default:
   4536 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   4537 				    PCAP_ERRBUF_SIZE, errno,
   4538 				    "SIOCSHWTSTAMP failed");
   4539 				*status = PCAP_ERROR;
   4540 				return -1;
   4541 			}
   4542 		} else {
   4543 			/*
   4544 			 * Well, that worked.  Now specify the type of
   4545 			 * hardware time stamp we want for this
   4546 			 * socket.
   4547 			 */
   4548 			if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) {
   4549 				/*
   4550 				 * Hardware timestamp, synchronized
   4551 				 * with the system clock.
   4552 				 */
   4553 				timesource = SOF_TIMESTAMPING_SYS_HARDWARE;
   4554 			} else {
   4555 				/*
   4556 				 * PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware
   4557 				 * timestamp, not synchronized with the
   4558 				 * system clock.
   4559 				 */
   4560 				timesource = SOF_TIMESTAMPING_RAW_HARDWARE;
   4561 			}
   4562 			if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP,
   4563 				(void *)&timesource, sizeof(timesource))) {
   4564 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   4565 				    PCAP_ERRBUF_SIZE, errno,
   4566 				    "can't set PACKET_TIMESTAMP");
   4567 				*status = PCAP_ERROR;
   4568 				return -1;
   4569 			}
   4570 		}
   4571 	}
   4572 #endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */
   4573 
   4574 	/* ask the kernel to create the ring */
   4575 retry:
   4576 	req.tp_block_nr = req.tp_frame_nr / frames_per_block;
   4577 
   4578 	/* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */
   4579 	req.tp_frame_nr = req.tp_block_nr * frames_per_block;
   4580 
   4581 #ifdef HAVE_TPACKET3
   4582 	/* timeout value to retire block - use the configured buffering timeout, or default if <0. */
   4583 	req.tp_retire_blk_tov = (handlep->timeout>=0)?handlep->timeout:0;
   4584 	/* private data not used */
   4585 	req.tp_sizeof_priv = 0;
   4586 	/* Rx ring - feature request bits - none (rxhash will not be filled) */
   4587 	req.tp_feature_req_word = 0;
   4588 #endif
   4589 
   4590 	if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
   4591 					(void *) &req, sizeof(req))) {
   4592 		if ((errno == ENOMEM) && (req.tp_block_nr > 1)) {
   4593 			/*
   4594 			 * Memory failure; try to reduce the requested ring
   4595 			 * size.
   4596 			 *
   4597 			 * We used to reduce this by half -- do 5% instead.
   4598 			 * That may result in more iterations and a longer
   4599 			 * startup, but the user will be much happier with
   4600 			 * the resulting buffer size.
   4601 			 */
   4602 			if (req.tp_frame_nr < 20)
   4603 				req.tp_frame_nr -= 1;
   4604 			else
   4605 				req.tp_frame_nr -= req.tp_frame_nr/20;
   4606 			goto retry;
   4607 		}
   4608 		if (errno == ENOPROTOOPT) {
   4609 			/*
   4610 			 * We don't have ring buffer support in this kernel.
   4611 			 */
   4612 			return 0;
   4613 		}
   4614 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4615 		    errno, "can't create rx ring on packet socket");
   4616 		*status = PCAP_ERROR;
   4617 		return -1;
   4618 	}
   4619 
   4620 	/* memory map the rx ring */
   4621 	handlep->mmapbuflen = req.tp_block_nr * req.tp_block_size;
   4622 	handlep->mmapbuf = mmap(0, handlep->mmapbuflen,
   4623 	    PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
   4624 	if (handlep->mmapbuf == MAP_FAILED) {
   4625 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4626 		    errno, "can't mmap rx ring");
   4627 
   4628 		/* clear the allocated ring on error*/
   4629 		destroy_ring(handle);
   4630 		*status = PCAP_ERROR;
   4631 		return -1;
   4632 	}
   4633 
   4634 	/* allocate a ring for each frame header pointer*/
   4635 	handle->cc = req.tp_frame_nr;
   4636 	handle->buffer = malloc(handle->cc * sizeof(union thdr *));
   4637 	if (!handle->buffer) {
   4638 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   4639 		    errno, "can't allocate ring of frame headers");
   4640 
   4641 		destroy_ring(handle);
   4642 		*status = PCAP_ERROR;
   4643 		return -1;
   4644 	}
   4645 
   4646 	/* fill the header ring with proper frame ptr*/
   4647 	handle->offset = 0;
   4648 	for (i=0; i<req.tp_block_nr; ++i) {
   4649 		void *base = &handlep->mmapbuf[i*req.tp_block_size];
   4650 		for (j=0; j<frames_per_block; ++j, ++handle->offset) {
   4651 			RING_GET_CURRENT_FRAME(handle) = base;
   4652 			base += req.tp_frame_size;
   4653 		}
   4654 	}
   4655 
   4656 	handle->bufsize = req.tp_frame_size;
   4657 	handle->offset = 0;
   4658 	return 1;
   4659 }
   4660 
   4661 /* free all ring related resources*/
   4662 static void
   4663 destroy_ring(pcap_t *handle)
   4664 {
   4665 	struct pcap_linux *handlep = handle->priv;
   4666 
   4667 	/* tell the kernel to destroy the ring*/
   4668 	struct tpacket_req req;
   4669 	memset(&req, 0, sizeof(req));
   4670 	/* do not test for setsockopt failure, as we can't recover from any error */
   4671 	(void)setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
   4672 				(void *) &req, sizeof(req));
   4673 
   4674 	/* if ring is mapped, unmap it*/
   4675 	if (handlep->mmapbuf) {
   4676 		/* do not test for mmap failure, as we can't recover from any error */
   4677 		(void)munmap(handlep->mmapbuf, handlep->mmapbuflen);
   4678 		handlep->mmapbuf = NULL;
   4679 	}
   4680 }
   4681 
   4682 /*
   4683  * Special one-shot callback, used for pcap_next() and pcap_next_ex(),
   4684  * for Linux mmapped capture.
   4685  *
   4686  * The problem is that pcap_next() and pcap_next_ex() expect the packet
   4687  * data handed to the callback to be valid after the callback returns,
   4688  * but pcap_read_linux_mmap() has to release that packet as soon as
   4689  * the callback returns (otherwise, the kernel thinks there's still
   4690  * at least one unprocessed packet available in the ring, so a select()
   4691  * will immediately return indicating that there's data to process), so,
   4692  * in the callback, we have to make a copy of the packet.
   4693  *
   4694  * Yes, this means that, if the capture is using the ring buffer, using
   4695  * pcap_next() or pcap_next_ex() requires more copies than using
   4696  * pcap_loop() or pcap_dispatch().  If that bothers you, don't use
   4697  * pcap_next() or pcap_next_ex().
   4698  */
   4699 static void
   4700 pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
   4701     const u_char *bytes)
   4702 {
   4703 	struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
   4704 	pcap_t *handle = sp->pd;
   4705 	struct pcap_linux *handlep = handle->priv;
   4706 
   4707 	*sp->hdr = *h;
   4708 	memcpy(handlep->oneshot_buffer, bytes, h->caplen);
   4709 	*sp->pkt = handlep->oneshot_buffer;
   4710 }
   4711 
   4712 static void
   4713 pcap_cleanup_linux_mmap( pcap_t *handle )
   4714 {
   4715 	struct pcap_linux *handlep = handle->priv;
   4716 
   4717 	destroy_ring(handle);
   4718 	if (handlep->oneshot_buffer != NULL) {
   4719 		free(handlep->oneshot_buffer);
   4720 		handlep->oneshot_buffer = NULL;
   4721 	}
   4722 	pcap_cleanup_linux(handle);
   4723 }
   4724 
   4725 
   4726 static int
   4727 pcap_getnonblock_mmap(pcap_t *handle)
   4728 {
   4729 	struct pcap_linux *handlep = handle->priv;
   4730 
   4731 	/* use negative value of timeout to indicate non blocking ops */
   4732 	return (handlep->timeout<0);
   4733 }
   4734 
   4735 static int
   4736 pcap_setnonblock_mmap(pcap_t *handle, int nonblock)
   4737 {
   4738 	struct pcap_linux *handlep = handle->priv;
   4739 
   4740 	/*
   4741 	 * Set the file descriptor to non-blocking mode, as we use
   4742 	 * it for sending packets.
   4743 	 */
   4744 	if (pcap_setnonblock_fd(handle, nonblock) == -1)
   4745 		return -1;
   4746 
   4747 	/*
   4748 	 * Map each value to their corresponding negation to
   4749 	 * preserve the timeout value provided with pcap_set_timeout.
   4750 	 */
   4751 	if (nonblock) {
   4752 		if (handlep->timeout >= 0) {
   4753 			/*
   4754 			 * Indicate that we're switching to
   4755 			 * non-blocking mode.
   4756 			 */
   4757 			handlep->timeout = ~handlep->timeout;
   4758 		}
   4759 	} else {
   4760 		if (handlep->timeout < 0) {
   4761 			handlep->timeout = ~handlep->timeout;
   4762 		}
   4763 	}
   4764 	/* Update the timeout to use in poll(). */
   4765 	set_poll_timeout(handlep);
   4766 	return 0;
   4767 }
   4768 
   4769 /*
   4770  * Get the status field of the ring buffer frame at a specified offset.
   4771  */
   4772 static inline int
   4773 pcap_get_ring_frame_status(pcap_t *handle, int offset)
   4774 {
   4775 	struct pcap_linux *handlep = handle->priv;
   4776 	union thdr h;
   4777 
   4778 	h.raw = RING_GET_FRAME_AT(handle, offset);
   4779 	switch (handlep->tp_version) {
   4780 	case TPACKET_V1:
   4781 		return (h.h1->tp_status);
   4782 		break;
   4783 	case TPACKET_V1_64:
   4784 		return (h.h1_64->tp_status);
   4785 		break;
   4786 #ifdef HAVE_TPACKET2
   4787 	case TPACKET_V2:
   4788 		return (h.h2->tp_status);
   4789 		break;
   4790 #endif
   4791 #ifdef HAVE_TPACKET3
   4792 	case TPACKET_V3:
   4793 		return (h.h3->hdr.bh1.block_status);
   4794 		break;
   4795 #endif
   4796 	}
   4797 	/* This should not happen. */
   4798 	return 0;
   4799 }
   4800 
   4801 #ifndef POLLRDHUP
   4802 #define POLLRDHUP 0
   4803 #endif
   4804 
   4805 /*
   4806  * Block waiting for frames to be available.
   4807  */
   4808 static int pcap_wait_for_frames_mmap(pcap_t *handle)
   4809 {
   4810 	struct pcap_linux *handlep = handle->priv;
   4811 	char c;
   4812 	struct pollfd pollinfo;
   4813 	int ret;
   4814 
   4815 	pollinfo.fd = handle->fd;
   4816 	pollinfo.events = POLLIN;
   4817 
   4818 	do {
   4819 		/*
   4820 		 * Yes, we do this even in non-blocking mode, as it's
   4821 		 * the only way to get error indications from a
   4822 		 * tpacket socket.
   4823 		 *
   4824 		 * The timeout is 0 in non-blocking mode, so poll()
   4825 		 * returns immediately.
   4826 		 */
   4827 		ret = poll(&pollinfo, 1, handlep->poll_timeout);
   4828 		if (ret < 0 && errno != EINTR) {
   4829 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   4830 			    PCAP_ERRBUF_SIZE, errno,
   4831 			    "can't poll on packet socket");
   4832 			return PCAP_ERROR;
   4833 		} else if (ret > 0 &&
   4834 			(pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
   4835 			/*
   4836 			 * There's some indication other than
   4837 			 * "you can read on this descriptor" on
   4838 			 * the descriptor.
   4839 			 */
   4840 			if (pollinfo.revents & (POLLHUP | POLLRDHUP)) {
   4841 				pcap_snprintf(handle->errbuf,
   4842 					PCAP_ERRBUF_SIZE,
   4843 					"Hangup on packet socket");
   4844 				return PCAP_ERROR;
   4845 			}
   4846 			if (pollinfo.revents & POLLERR) {
   4847 				/*
   4848 				 * A recv() will give us the actual error code.
   4849 				 *
   4850 				 * XXX - make the socket non-blocking?
   4851 				 */
   4852 				if (recv(handle->fd, &c, sizeof c,
   4853 					MSG_PEEK) != -1)
   4854 					continue;	/* what, no error? */
   4855 				if (errno == ENETDOWN) {
   4856 					/*
   4857 					 * The device on which we're
   4858 					 * capturing went away.
   4859 					 *
   4860 					 * XXX - we should really return
   4861 					 * PCAP_ERROR_IFACE_NOT_UP, but
   4862 					 * pcap_dispatch() etc. aren't
   4863 					 * defined to return that.
   4864 					 */
   4865 					pcap_snprintf(handle->errbuf,
   4866 						PCAP_ERRBUF_SIZE,
   4867 						"The interface went down");
   4868 				} else {
   4869 					pcap_fmt_errmsg_for_errno(handle->errbuf,
   4870 					    PCAP_ERRBUF_SIZE, errno,
   4871 					    "Error condition on packet socket");
   4872 				}
   4873 				return PCAP_ERROR;
   4874 			}
   4875 			if (pollinfo.revents & POLLNVAL) {
   4876 				pcap_snprintf(handle->errbuf,
   4877 					PCAP_ERRBUF_SIZE,
   4878 					"Invalid polling request on packet socket");
   4879 				return PCAP_ERROR;
   4880 			}
   4881 		}
   4882 		/* check for break loop condition on interrupted syscall*/
   4883 		if (handle->break_loop) {
   4884 			handle->break_loop = 0;
   4885 			return PCAP_ERROR_BREAK;
   4886 		}
   4887 	} while (ret < 0);
   4888 	return 0;
   4889 }
   4890 
   4891 /* handle a single memory mapped packet */
   4892 static int pcap_handle_packet_mmap(
   4893 		pcap_t *handle,
   4894 		pcap_handler callback,
   4895 		u_char *user,
   4896 		unsigned char *frame,
   4897 		unsigned int tp_len,
   4898 		unsigned int tp_mac,
   4899 		unsigned int tp_snaplen,
   4900 		unsigned int tp_sec,
   4901 		unsigned int tp_usec,
   4902 		int tp_vlan_tci_valid,
   4903 		__u16 tp_vlan_tci,
   4904 		__u16 tp_vlan_tpid)
   4905 {
   4906 	struct pcap_linux *handlep = handle->priv;
   4907 	unsigned char *bp;
   4908 	struct sockaddr_ll *sll;
   4909 	struct pcap_pkthdr pcaphdr;
   4910 	unsigned int snaplen = tp_snaplen;
   4911 
   4912 	/* perform sanity check on internal offset. */
   4913 	if (tp_mac + tp_snaplen > handle->bufsize) {
   4914 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   4915 			"corrupted frame on kernel ring mac "
   4916 			"offset %u + caplen %u > frame len %d",
   4917 			tp_mac, tp_snaplen, handle->bufsize);
   4918 		return -1;
   4919 	}
   4920 
   4921 	/* run filter on received packet
   4922 	 * If the kernel filtering is enabled we need to run the
   4923 	 * filter until all the frames present into the ring
   4924 	 * at filter creation time are processed.
   4925 	 * In this case, blocks_to_filter_in_userland is used
   4926 	 * as a counter for the packet we need to filter.
   4927 	 * Note: alternatively it could be possible to stop applying
   4928 	 * the filter when the ring became empty, but it can possibly
   4929 	 * happen a lot later... */
   4930 	bp = frame + tp_mac;
   4931 
   4932 	/* if required build in place the sll header*/
   4933 	sll = (void *)frame + TPACKET_ALIGN(handlep->tp_hdrlen);
   4934 	if (handlep->cooked) {
   4935 		struct sll_header *hdrp;
   4936 
   4937 		/*
   4938 		 * The kernel should have left us with enough
   4939 		 * space for an sll header; back up the packet
   4940 		 * data pointer into that space, as that'll be
   4941 		 * the beginning of the packet we pass to the
   4942 		 * callback.
   4943 		 */
   4944 		bp -= SLL_HDR_LEN;
   4945 
   4946 		/*
   4947 		 * Let's make sure that's past the end of
   4948 		 * the tpacket header, i.e. >=
   4949 		 * ((u_char *)thdr + TPACKET_HDRLEN), so we
   4950 		 * don't step on the header when we construct
   4951 		 * the sll header.
   4952 		 */
   4953 		if (bp < (u_char *)frame +
   4954 				   TPACKET_ALIGN(handlep->tp_hdrlen) +
   4955 				   sizeof(struct sockaddr_ll)) {
   4956 			pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   4957 				"cooked-mode frame doesn't have room for sll header");
   4958 			return -1;
   4959 		}
   4960 
   4961 		/*
   4962 		 * OK, that worked; construct the sll header.
   4963 		 */
   4964 		hdrp = (struct sll_header *)bp;
   4965 		hdrp->sll_pkttype = map_packet_type_to_sll_type(
   4966 						sll->sll_pkttype);
   4967 		hdrp->sll_hatype = htons(sll->sll_hatype);
   4968 		hdrp->sll_halen = htons(sll->sll_halen);
   4969 		memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN);
   4970 		hdrp->sll_protocol = sll->sll_protocol;
   4971 
   4972 		snaplen += sizeof(struct sll_header);
   4973 	}
   4974 
   4975 	if (handlep->filter_in_userland && handle->fcode.bf_insns) {
   4976 		struct bpf_aux_data aux_data;
   4977 
   4978 		aux_data.vlan_tag_present = tp_vlan_tci_valid;
   4979 		aux_data.vlan_tag = tp_vlan_tci & 0x0fff;
   4980 
   4981 		if (bpf_filter_with_aux_data(handle->fcode.bf_insns,
   4982 					     bp,
   4983 					     tp_len,
   4984 					     snaplen,
   4985 					     &aux_data) == 0)
   4986 			return 0;
   4987 	}
   4988 
   4989 	if (!linux_check_direction(handle, sll))
   4990 		return 0;
   4991 
   4992 	/* get required packet info from ring header */
   4993 	pcaphdr.ts.tv_sec = tp_sec;
   4994 	pcaphdr.ts.tv_usec = tp_usec;
   4995 	pcaphdr.caplen = tp_snaplen;
   4996 	pcaphdr.len = tp_len;
   4997 
   4998 	/* if required build in place the sll header*/
   4999 	if (handlep->cooked) {
   5000 		/* update packet len */
   5001 		pcaphdr.caplen += SLL_HDR_LEN;
   5002 		pcaphdr.len += SLL_HDR_LEN;
   5003 	}
   5004 
   5005 #if defined(HAVE_TPACKET2) || defined(HAVE_TPACKET3)
   5006 	if (tp_vlan_tci_valid &&
   5007 		handlep->vlan_offset != -1 &&
   5008 		tp_snaplen >= (unsigned int) handlep->vlan_offset)
   5009 	{
   5010 		struct vlan_tag *tag;
   5011 
   5012 		/*
   5013 		 * Move everything in the header, except the type field,
   5014 		 * down VLAN_TAG_LEN bytes, to allow us to insert the
   5015 		 * VLAN tag between that stuff and the type field.
   5016 		 */
   5017 		bp -= VLAN_TAG_LEN;
   5018 		memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
   5019 
   5020 		/*
   5021 		 * Now insert the tag.
   5022 		 */
   5023 		tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
   5024 		tag->vlan_tpid = htons(tp_vlan_tpid);
   5025 		tag->vlan_tci = htons(tp_vlan_tci);
   5026 
   5027 		/*
   5028 		 * Add the tag to the packet lengths.
   5029 		 */
   5030 		pcaphdr.caplen += VLAN_TAG_LEN;
   5031 		pcaphdr.len += VLAN_TAG_LEN;
   5032 	}
   5033 #endif
   5034 
   5035 	/*
   5036 	 * The only way to tell the kernel to cut off the
   5037 	 * packet at a snapshot length is with a filter program;
   5038 	 * if there's no filter program, the kernel won't cut
   5039 	 * the packet off.
   5040 	 *
   5041 	 * Trim the snapshot length to be no longer than the
   5042 	 * specified snapshot length.
   5043 	 */
   5044 	if (pcaphdr.caplen > (bpf_u_int32)handle->snapshot)
   5045 		pcaphdr.caplen = handle->snapshot;
   5046 
   5047 	/* pass the packet to the user */
   5048 	callback(user, &pcaphdr, bp);
   5049 
   5050 	return 1;
   5051 }
   5052 
   5053 static int
   5054 pcap_read_linux_mmap_v1(pcap_t *handle, int max_packets, pcap_handler callback,
   5055 		u_char *user)
   5056 {
   5057 	struct pcap_linux *handlep = handle->priv;
   5058 	union thdr h;
   5059 	int pkts = 0;
   5060 	int ret;
   5061 
   5062 	/* wait for frames availability.*/
   5063 	h.raw = RING_GET_CURRENT_FRAME(handle);
   5064 	if (h.h1->tp_status == TP_STATUS_KERNEL) {
   5065 		/*
   5066 		 * The current frame is owned by the kernel; wait for
   5067 		 * a frame to be handed to us.
   5068 		 */
   5069 		ret = pcap_wait_for_frames_mmap(handle);
   5070 		if (ret) {
   5071 			return ret;
   5072 		}
   5073 	}
   5074 
   5075 	/* non-positive values of max_packets are used to require all
   5076 	 * packets currently available in the ring */
   5077 	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
   5078 		/*
   5079 		 * Get the current ring buffer frame, and break if
   5080 		 * it's still owned by the kernel.
   5081 		 */
   5082 		h.raw = RING_GET_CURRENT_FRAME(handle);
   5083 		if (h.h1->tp_status == TP_STATUS_KERNEL)
   5084 			break;
   5085 
   5086 		ret = pcap_handle_packet_mmap(
   5087 				handle,
   5088 				callback,
   5089 				user,
   5090 				h.raw,
   5091 				h.h1->tp_len,
   5092 				h.h1->tp_mac,
   5093 				h.h1->tp_snaplen,
   5094 				h.h1->tp_sec,
   5095 				h.h1->tp_usec,
   5096 				0,
   5097 				0,
   5098 				0);
   5099 		if (ret == 1) {
   5100 			pkts++;
   5101 			handlep->packets_read++;
   5102 		} else if (ret < 0) {
   5103 			return ret;
   5104 		}
   5105 
   5106 		/*
   5107 		 * Hand this block back to the kernel, and, if we're
   5108 		 * counting blocks that need to be filtered in userland
   5109 		 * after having been filtered by the kernel, count
   5110 		 * the one we've just processed.
   5111 		 */
   5112 		h.h1->tp_status = TP_STATUS_KERNEL;
   5113 		if (handlep->blocks_to_filter_in_userland > 0) {
   5114 			handlep->blocks_to_filter_in_userland--;
   5115 			if (handlep->blocks_to_filter_in_userland == 0) {
   5116 				/*
   5117 				 * No more blocks need to be filtered
   5118 				 * in userland.
   5119 				 */
   5120 				handlep->filter_in_userland = 0;
   5121 			}
   5122 		}
   5123 
   5124 		/* next block */
   5125 		if (++handle->offset >= handle->cc)
   5126 			handle->offset = 0;
   5127 
   5128 		/* check for break loop condition*/
   5129 		if (handle->break_loop) {
   5130 			handle->break_loop = 0;
   5131 			return PCAP_ERROR_BREAK;
   5132 		}
   5133 	}
   5134 	return pkts;
   5135 }
   5136 
   5137 static int
   5138 pcap_read_linux_mmap_v1_64(pcap_t *handle, int max_packets, pcap_handler callback,
   5139 		u_char *user)
   5140 {
   5141 	struct pcap_linux *handlep = handle->priv;
   5142 	union thdr h;
   5143 	int pkts = 0;
   5144 	int ret;
   5145 
   5146 	/* wait for frames availability.*/
   5147 	h.raw = RING_GET_CURRENT_FRAME(handle);
   5148 	if (h.h1_64->tp_status == TP_STATUS_KERNEL) {
   5149 		/*
   5150 		 * The current frame is owned by the kernel; wait for
   5151 		 * a frame to be handed to us.
   5152 		 */
   5153 		ret = pcap_wait_for_frames_mmap(handle);
   5154 		if (ret) {
   5155 			return ret;
   5156 		}
   5157 	}
   5158 
   5159 	/* non-positive values of max_packets are used to require all
   5160 	 * packets currently available in the ring */
   5161 	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
   5162 		/*
   5163 		 * Get the current ring buffer frame, and break if
   5164 		 * it's still owned by the kernel.
   5165 		 */
   5166 		h.raw = RING_GET_CURRENT_FRAME(handle);
   5167 		if (h.h1_64->tp_status == TP_STATUS_KERNEL)
   5168 			break;
   5169 
   5170 		ret = pcap_handle_packet_mmap(
   5171 				handle,
   5172 				callback,
   5173 				user,
   5174 				h.raw,
   5175 				h.h1_64->tp_len,
   5176 				h.h1_64->tp_mac,
   5177 				h.h1_64->tp_snaplen,
   5178 				h.h1_64->tp_sec,
   5179 				h.h1_64->tp_usec,
   5180 				0,
   5181 				0,
   5182 				0);
   5183 		if (ret == 1) {
   5184 			pkts++;
   5185 			handlep->packets_read++;
   5186 		} else if (ret < 0) {
   5187 			return ret;
   5188 		}
   5189 
   5190 		/*
   5191 		 * Hand this block back to the kernel, and, if we're
   5192 		 * counting blocks that need to be filtered in userland
   5193 		 * after having been filtered by the kernel, count
   5194 		 * the one we've just processed.
   5195 		 */
   5196 		h.h1_64->tp_status = TP_STATUS_KERNEL;
   5197 		if (handlep->blocks_to_filter_in_userland > 0) {
   5198 			handlep->blocks_to_filter_in_userland--;
   5199 			if (handlep->blocks_to_filter_in_userland == 0) {
   5200 				/*
   5201 				 * No more blocks need to be filtered
   5202 				 * in userland.
   5203 				 */
   5204 				handlep->filter_in_userland = 0;
   5205 			}
   5206 		}
   5207 
   5208 		/* next block */
   5209 		if (++handle->offset >= handle->cc)
   5210 			handle->offset = 0;
   5211 
   5212 		/* check for break loop condition*/
   5213 		if (handle->break_loop) {
   5214 			handle->break_loop = 0;
   5215 			return PCAP_ERROR_BREAK;
   5216 		}
   5217 	}
   5218 	return pkts;
   5219 }
   5220 
   5221 #ifdef HAVE_TPACKET2
   5222 static int
   5223 pcap_read_linux_mmap_v2(pcap_t *handle, int max_packets, pcap_handler callback,
   5224 		u_char *user)
   5225 {
   5226 	struct pcap_linux *handlep = handle->priv;
   5227 	union thdr h;
   5228 	int pkts = 0;
   5229 	int ret;
   5230 
   5231 	/* wait for frames availability.*/
   5232 	h.raw = RING_GET_CURRENT_FRAME(handle);
   5233 	if (h.h2->tp_status == TP_STATUS_KERNEL) {
   5234 		/*
   5235 		 * The current frame is owned by the kernel; wait for
   5236 		 * a frame to be handed to us.
   5237 		 */
   5238 		ret = pcap_wait_for_frames_mmap(handle);
   5239 		if (ret) {
   5240 			return ret;
   5241 		}
   5242 	}
   5243 
   5244 	/* non-positive values of max_packets are used to require all
   5245 	 * packets currently available in the ring */
   5246 	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
   5247 		/*
   5248 		 * Get the current ring buffer frame, and break if
   5249 		 * it's still owned by the kernel.
   5250 		 */
   5251 		h.raw = RING_GET_CURRENT_FRAME(handle);
   5252 		if (h.h2->tp_status == TP_STATUS_KERNEL)
   5253 			break;
   5254 
   5255 		ret = pcap_handle_packet_mmap(
   5256 				handle,
   5257 				callback,
   5258 				user,
   5259 				h.raw,
   5260 				h.h2->tp_len,
   5261 				h.h2->tp_mac,
   5262 				h.h2->tp_snaplen,
   5263 				h.h2->tp_sec,
   5264 				handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? h.h2->tp_nsec : h.h2->tp_nsec / 1000,
   5265 				VLAN_VALID(h.h2, h.h2),
   5266 				h.h2->tp_vlan_tci,
   5267 				VLAN_TPID(h.h2, h.h2));
   5268 		if (ret == 1) {
   5269 			pkts++;
   5270 			handlep->packets_read++;
   5271 		} else if (ret < 0) {
   5272 			return ret;
   5273 		}
   5274 
   5275 		/*
   5276 		 * Hand this block back to the kernel, and, if we're
   5277 		 * counting blocks that need to be filtered in userland
   5278 		 * after having been filtered by the kernel, count
   5279 		 * the one we've just processed.
   5280 		 */
   5281 		h.h2->tp_status = TP_STATUS_KERNEL;
   5282 		if (handlep->blocks_to_filter_in_userland > 0) {
   5283 			handlep->blocks_to_filter_in_userland--;
   5284 			if (handlep->blocks_to_filter_in_userland == 0) {
   5285 				/*
   5286 				 * No more blocks need to be filtered
   5287 				 * in userland.
   5288 				 */
   5289 				handlep->filter_in_userland = 0;
   5290 			}
   5291 		}
   5292 
   5293 		/* next block */
   5294 		if (++handle->offset >= handle->cc)
   5295 			handle->offset = 0;
   5296 
   5297 		/* check for break loop condition*/
   5298 		if (handle->break_loop) {
   5299 			handle->break_loop = 0;
   5300 			return PCAP_ERROR_BREAK;
   5301 		}
   5302 	}
   5303 	return pkts;
   5304 }
   5305 #endif /* HAVE_TPACKET2 */
   5306 
   5307 #ifdef HAVE_TPACKET3
   5308 static int
   5309 pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
   5310 		u_char *user)
   5311 {
   5312 	struct pcap_linux *handlep = handle->priv;
   5313 	union thdr h;
   5314 	int pkts = 0;
   5315 	int ret;
   5316 
   5317 again:
   5318 	if (handlep->current_packet == NULL) {
   5319 		/* wait for frames availability.*/
   5320 		h.raw = RING_GET_CURRENT_FRAME(handle);
   5321 		if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL) {
   5322 			/*
   5323 			 * The current frame is owned by the kernel; wait
   5324 			 * for a frame to be handed to us.
   5325 			 */
   5326 			ret = pcap_wait_for_frames_mmap(handle);
   5327 			if (ret) {
   5328 				return ret;
   5329 			}
   5330 		}
   5331 	}
   5332 	h.raw = RING_GET_CURRENT_FRAME(handle);
   5333 	if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL) {
   5334 		if (pkts == 0 && handlep->timeout == 0) {
   5335 			/* Block until we see a packet. */
   5336 			goto again;
   5337 		}
   5338 		return pkts;
   5339 	}
   5340 
   5341 	/* non-positive values of max_packets are used to require all
   5342 	 * packets currently available in the ring */
   5343 	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
   5344 		int packets_to_read;
   5345 
   5346 		if (handlep->current_packet == NULL) {
   5347 			h.raw = RING_GET_CURRENT_FRAME(handle);
   5348 			if (h.h3->hdr.bh1.block_status == TP_STATUS_KERNEL)
   5349 				break;
   5350 
   5351 			handlep->current_packet = h.raw + h.h3->hdr.bh1.offset_to_first_pkt;
   5352 			handlep->packets_left = h.h3->hdr.bh1.num_pkts;
   5353 		}
   5354 		packets_to_read = handlep->packets_left;
   5355 
   5356 		if (!PACKET_COUNT_IS_UNLIMITED(max_packets) &&
   5357 		    packets_to_read > (max_packets - pkts)) {
   5358 			/*
   5359 			 * We've been given a maximum number of packets
   5360 			 * to process, and there are more packets in
   5361 			 * this buffer than that.  Only process enough
   5362 			 * of them to get us up to that maximum.
   5363 			 */
   5364 			packets_to_read = max_packets - pkts;
   5365 		}
   5366 
   5367 		while (packets_to_read-- && !handle->break_loop) {
   5368 			struct tpacket3_hdr* tp3_hdr = (struct tpacket3_hdr*) handlep->current_packet;
   5369 			ret = pcap_handle_packet_mmap(
   5370 					handle,
   5371 					callback,
   5372 					user,
   5373 					handlep->current_packet,
   5374 					tp3_hdr->tp_len,
   5375 					tp3_hdr->tp_mac,
   5376 					tp3_hdr->tp_snaplen,
   5377 					tp3_hdr->tp_sec,
   5378 					handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? tp3_hdr->tp_nsec : tp3_hdr->tp_nsec / 1000,
   5379 					VLAN_VALID(tp3_hdr, &tp3_hdr->hv1),
   5380 					tp3_hdr->hv1.tp_vlan_tci,
   5381 					VLAN_TPID(tp3_hdr, &tp3_hdr->hv1));
   5382 			if (ret == 1) {
   5383 				pkts++;
   5384 				handlep->packets_read++;
   5385 			} else if (ret < 0) {
   5386 				handlep->current_packet = NULL;
   5387 				return ret;
   5388 			}
   5389 			handlep->current_packet += tp3_hdr->tp_next_offset;
   5390 			handlep->packets_left--;
   5391 		}
   5392 
   5393 		if (handlep->packets_left <= 0) {
   5394 			/*
   5395 			 * Hand this block back to the kernel, and, if
   5396 			 * we're counting blocks that need to be
   5397 			 * filtered in userland after having been
   5398 			 * filtered by the kernel, count the one we've
   5399 			 * just processed.
   5400 			 */
   5401 			h.h3->hdr.bh1.block_status = TP_STATUS_KERNEL;
   5402 			if (handlep->blocks_to_filter_in_userland > 0) {
   5403 				handlep->blocks_to_filter_in_userland--;
   5404 				if (handlep->blocks_to_filter_in_userland == 0) {
   5405 					/*
   5406 					 * No more blocks need to be filtered
   5407 					 * in userland.
   5408 					 */
   5409 					handlep->filter_in_userland = 0;
   5410 				}
   5411 			}
   5412 
   5413 			/* next block */
   5414 			if (++handle->offset >= handle->cc)
   5415 				handle->offset = 0;
   5416 
   5417 			handlep->current_packet = NULL;
   5418 		}
   5419 
   5420 		/* check for break loop condition*/
   5421 		if (handle->break_loop) {
   5422 			handle->break_loop = 0;
   5423 			return PCAP_ERROR_BREAK;
   5424 		}
   5425 	}
   5426 	if (pkts == 0 && handlep->timeout == 0) {
   5427 		/* Block until we see a packet. */
   5428 		goto again;
   5429 	}
   5430 	return pkts;
   5431 }
   5432 #endif /* HAVE_TPACKET3 */
   5433 
   5434 static int
   5435 pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter)
   5436 {
   5437 	struct pcap_linux *handlep = handle->priv;
   5438 	int n, offset;
   5439 	int ret;
   5440 
   5441 	/*
   5442 	 * Don't rewrite "ret" instructions; we don't need to, as
   5443 	 * we're not reading packets with recvmsg(), and we don't
   5444 	 * want to, as, by not rewriting them, the kernel can avoid
   5445 	 * copying extra data.
   5446 	 */
   5447 	ret = pcap_setfilter_linux_common(handle, filter, 1);
   5448 	if (ret < 0)
   5449 		return ret;
   5450 
   5451 	/*
   5452 	 * If we're filtering in userland, there's nothing to do;
   5453 	 * the new filter will be used for the next packet.
   5454 	 */
   5455 	if (handlep->filter_in_userland)
   5456 		return ret;
   5457 
   5458 	/*
   5459 	 * We're filtering in the kernel; the packets present in
   5460 	 * all blocks currently in the ring were already filtered
   5461 	 * by the old filter, and so will need to be filtered in
   5462 	 * userland by the new filter.
   5463 	 *
   5464 	 * Get an upper bound for the number of such blocks; first,
   5465 	 * walk the ring backward and count the free blocks.
   5466 	 */
   5467 	offset = handle->offset;
   5468 	if (--offset < 0)
   5469 		offset = handle->cc - 1;
   5470 	for (n=0; n < handle->cc; ++n) {
   5471 		if (--offset < 0)
   5472 			offset = handle->cc - 1;
   5473 		if (pcap_get_ring_frame_status(handle, offset) != TP_STATUS_KERNEL)
   5474 			break;
   5475 	}
   5476 
   5477 	/*
   5478 	 * If we found free blocks, decrement the count of free
   5479 	 * blocks by 1, just in case we lost a race with another
   5480 	 * thread of control that was adding a packet while
   5481 	 * we were counting and that had run the filter before
   5482 	 * we changed it.
   5483 	 *
   5484 	 * XXX - could there be more than one block added in
   5485 	 * this fashion?
   5486 	 *
   5487 	 * XXX - is there a way to avoid that race, e.g. somehow
   5488 	 * wait for all packets that passed the old filter to
   5489 	 * be added to the ring?
   5490 	 */
   5491 	if (n != 0)
   5492 		n--;
   5493 
   5494 	/*
   5495 	 * Set the count of blocks worth of packets to filter
   5496 	 * in userland to the total number of blocks in the
   5497 	 * ring minus the number of free blocks we found, and
   5498 	 * turn on userland filtering.  (The count of blocks
   5499 	 * worth of packets to filter in userland is guaranteed
   5500 	 * not to be zero - n, above, couldn't be set to a
   5501 	 * value > handle->cc, and if it were equal to
   5502 	 * handle->cc, it wouldn't be zero, and thus would
   5503 	 * be decremented to handle->cc - 1.)
   5504 	 */
   5505 	handlep->blocks_to_filter_in_userland = handle->cc - n;
   5506 	handlep->filter_in_userland = 1;
   5507 	return ret;
   5508 }
   5509 
   5510 #endif /* HAVE_PACKET_RING */
   5511 
   5512 
   5513 #ifdef HAVE_PF_PACKET_SOCKETS
   5514 /*
   5515  *  Return the index of the given device name. Fill ebuf and return
   5516  *  -1 on failure.
   5517  */
   5518 static int
   5519 iface_get_id(int fd, const char *device, char *ebuf)
   5520 {
   5521 	struct ifreq	ifr;
   5522 
   5523 	memset(&ifr, 0, sizeof(ifr));
   5524 	strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   5525 
   5526 	if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
   5527 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   5528 		    errno, "SIOCGIFINDEX");
   5529 		return -1;
   5530 	}
   5531 
   5532 	return ifr.ifr_ifindex;
   5533 }
   5534 
   5535 /*
   5536  *  Bind the socket associated with FD to the given device.
   5537  *  Return 1 on success, 0 if we should try a SOCK_PACKET socket,
   5538  *  or a PCAP_ERROR_ value on a hard error.
   5539  */
   5540 static int
   5541 iface_bind(int fd, int ifindex, char *ebuf, int protocol)
   5542 {
   5543 	struct sockaddr_ll	sll;
   5544 	int			err;
   5545 	socklen_t		errlen = sizeof(err);
   5546 
   5547 	memset(&sll, 0, sizeof(sll));
   5548 	sll.sll_family		= AF_PACKET;
   5549 	sll.sll_ifindex		= ifindex;
   5550 	sll.sll_protocol	= protocol;
   5551 
   5552 	if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
   5553 		if (errno == ENETDOWN) {
   5554 			/*
   5555 			 * Return a "network down" indication, so that
   5556 			 * the application can report that rather than
   5557 			 * saying we had a mysterious failure and
   5558 			 * suggest that they report a problem to the
   5559 			 * libpcap developers.
   5560 			 */
   5561 			return PCAP_ERROR_IFACE_NOT_UP;
   5562 		} else {
   5563 			pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   5564 			    errno, "bind");
   5565 			return PCAP_ERROR;
   5566 		}
   5567 	}
   5568 
   5569 	/* Any pending errors, e.g., network is down? */
   5570 
   5571 	if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
   5572 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   5573 		    errno, "getsockopt");
   5574 		return 0;
   5575 	}
   5576 
   5577 	if (err == ENETDOWN) {
   5578 		/*
   5579 		 * Return a "network down" indication, so that
   5580 		 * the application can report that rather than
   5581 		 * saying we had a mysterious failure and
   5582 		 * suggest that they report a problem to the
   5583 		 * libpcap developers.
   5584 		 */
   5585 		return PCAP_ERROR_IFACE_NOT_UP;
   5586 	} else if (err > 0) {
   5587 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   5588 		    err, "bind");
   5589 		return 0;
   5590 	}
   5591 
   5592 	return 1;
   5593 }
   5594 
   5595 #ifdef IW_MODE_MONITOR
   5596 /*
   5597  * Check whether the device supports the Wireless Extensions.
   5598  * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
   5599  * if the device doesn't even exist.
   5600  */
   5601 static int
   5602 has_wext(int sock_fd, const char *device, char *ebuf)
   5603 {
   5604 	struct iwreq ireq;
   5605 
   5606 	if (is_bonding_device(sock_fd, device))
   5607 		return 0;	/* bonding device, so don't even try */
   5608 
   5609 	strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   5610 	    sizeof ireq.ifr_ifrn.ifrn_name);
   5611 	if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
   5612 		return 1;	/* yes */
   5613 	pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE, errno,
   5614 	    "%s: SIOCGIWNAME", device);
   5615 	if (errno == ENODEV)
   5616 		return PCAP_ERROR_NO_SUCH_DEVICE;
   5617 	return 0;
   5618 }
   5619 
   5620 /*
   5621  * Per me si va ne la citta dolente,
   5622  * Per me si va ne l'etterno dolore,
   5623  *	...
   5624  * Lasciate ogne speranza, voi ch'intrate.
   5625  *
   5626  * XXX - airmon-ng does special stuff with the Orinoco driver and the
   5627  * wlan-ng driver.
   5628  */
   5629 typedef enum {
   5630 	MONITOR_WEXT,
   5631 	MONITOR_HOSTAP,
   5632 	MONITOR_PRISM,
   5633 	MONITOR_PRISM54,
   5634 	MONITOR_ACX100,
   5635 	MONITOR_RT2500,
   5636 	MONITOR_RT2570,
   5637 	MONITOR_RT73,
   5638 	MONITOR_RTL8XXX
   5639 } monitor_type;
   5640 
   5641 /*
   5642  * Use the Wireless Extensions, if we have them, to try to turn monitor mode
   5643  * on if it's not already on.
   5644  *
   5645  * Returns 1 on success, 0 if we don't support the Wireless Extensions
   5646  * on this device, or a PCAP_ERROR_ value if we do support them but
   5647  * we weren't able to turn monitor mode on.
   5648  */
   5649 static int
   5650 enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
   5651 {
   5652 	/*
   5653 	 * XXX - at least some adapters require non-Wireless Extensions
   5654 	 * mechanisms to turn monitor mode on.
   5655 	 *
   5656 	 * Atheros cards might require that a separate "monitor virtual access
   5657 	 * point" be created, with later versions of the madwifi driver.
   5658 	 * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode
   5659 	 * monitor -bssid", which apparently spits out a line "athN"
   5660 	 * where "athN" is the monitor mode device.  To leave monitor
   5661 	 * mode, it destroys the monitor mode device.
   5662 	 *
   5663 	 * Some Intel Centrino adapters might require private ioctls to get
   5664 	 * radio headers; the ipw2200 and ipw3945 drivers allow you to
   5665 	 * configure a separate "rtapN" interface to capture in monitor
   5666 	 * mode without preventing the adapter from operating normally.
   5667 	 * (airmon-ng doesn't appear to use that, though.)
   5668 	 *
   5669 	 * It would be Truly Wonderful if mac80211 and nl80211 cleaned this
   5670 	 * up, and if all drivers were converted to mac80211 drivers.
   5671 	 *
   5672 	 * If interface {if} is a mac80211 driver, the file
   5673 	 * /sys/class/net/{if}/phy80211 is a symlink to
   5674 	 * /sys/class/ieee80211/{phydev}, for some {phydev}.
   5675 	 *
   5676 	 * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
   5677 	 * least, has a "wmaster0" device and a "wlan0" device; the
   5678 	 * latter is the one with the IP address.  Both show up in
   5679 	 * "tcpdump -D" output.  Capturing on the wmaster0 device
   5680 	 * captures with 802.11 headers.
   5681 	 *
   5682 	 * airmon-ng searches through /sys/class/net for devices named
   5683 	 * monN, starting with mon0; as soon as one *doesn't* exist,
   5684 	 * it chooses that as the monitor device name.  If the "iw"
   5685 	 * command exists, it does "iw dev {if} interface add {monif}
   5686 	 * type monitor", where {monif} is the monitor device.  It
   5687 	 * then (sigh) sleeps .1 second, and then configures the
   5688 	 * device up.  Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
   5689 	 * is a file, it writes {mondev}, without a newline, to that file,
   5690 	 * and again (sigh) sleeps .1 second, and then iwconfig's that
   5691 	 * device into monitor mode and configures it up.  Otherwise,
   5692 	 * you can't do monitor mode.
   5693 	 *
   5694 	 * All these devices are "glued" together by having the
   5695 	 * /sys/class/net/{device}/phy80211 links pointing to the same
   5696 	 * place, so, given a wmaster, wlan, or mon device, you can
   5697 	 * find the other devices by looking for devices with
   5698 	 * the same phy80211 link.
   5699 	 *
   5700 	 * To turn monitor mode off, delete the monitor interface,
   5701 	 * either with "iw dev {monif} interface del" or by sending
   5702 	 * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
   5703 	 *
   5704 	 * Note: if you try to create a monitor device named "monN", and
   5705 	 * there's already a "monN" device, it fails, as least with
   5706 	 * the netlink interface (which is what iw uses), with a return
   5707 	 * value of -ENFILE.  (Return values are negative errnos.)  We
   5708 	 * could probably use that to find an unused device.
   5709 	 */
   5710 	struct pcap_linux *handlep = handle->priv;
   5711 	int err;
   5712 	struct iwreq ireq;
   5713 	struct iw_priv_args *priv;
   5714 	monitor_type montype;
   5715 	int i;
   5716 	__u32 cmd;
   5717 	struct ifreq ifr;
   5718 	int oldflags;
   5719 	int args[2];
   5720 	int channel;
   5721 
   5722 	/*
   5723 	 * Does this device *support* the Wireless Extensions?
   5724 	 */
   5725 	err = has_wext(sock_fd, device, handle->errbuf);
   5726 	if (err <= 0)
   5727 		return err;	/* either it doesn't or the device doesn't even exist */
   5728 	/*
   5729 	 * Start out assuming we have no private extensions to control
   5730 	 * radio metadata.
   5731 	 */
   5732 	montype = MONITOR_WEXT;
   5733 	cmd = 0;
   5734 
   5735 	/*
   5736 	 * Try to get all the Wireless Extensions private ioctls
   5737 	 * supported by this device.
   5738 	 *
   5739 	 * First, get the size of the buffer we need, by supplying no
   5740 	 * buffer and a length of 0.  If the device supports private
   5741 	 * ioctls, it should return E2BIG, with ireq.u.data.length set
   5742 	 * to the length we need.  If it doesn't support them, it should
   5743 	 * return EOPNOTSUPP.
   5744 	 */
   5745 	memset(&ireq, 0, sizeof ireq);
   5746 	strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   5747 	    sizeof ireq.ifr_ifrn.ifrn_name);
   5748 	ireq.u.data.pointer = (void *)args;
   5749 	ireq.u.data.length = 0;
   5750 	ireq.u.data.flags = 0;
   5751 	if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
   5752 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   5753 		    "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
   5754 		    device);
   5755 		return PCAP_ERROR;
   5756 	}
   5757 	if (errno != EOPNOTSUPP) {
   5758 		/*
   5759 		 * OK, it's not as if there are no private ioctls.
   5760 		 */
   5761 		if (errno != E2BIG) {
   5762 			/*
   5763 			 * Failed.
   5764 			 */
   5765 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   5766 			    PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWPRIV", device);
   5767 			return PCAP_ERROR;
   5768 		}
   5769 
   5770 		/*
   5771 		 * OK, try to get the list of private ioctls.
   5772 		 */
   5773 		priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
   5774 		if (priv == NULL) {
   5775 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   5776 			    PCAP_ERRBUF_SIZE, errno, "malloc");
   5777 			return PCAP_ERROR;
   5778 		}
   5779 		ireq.u.data.pointer = (void *)priv;
   5780 		if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
   5781 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   5782 			    PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWPRIV", device);
   5783 			free(priv);
   5784 			return PCAP_ERROR;
   5785 		}
   5786 
   5787 		/*
   5788 		 * Look for private ioctls to turn monitor mode on or, if
   5789 		 * monitor mode is on, to set the header type.
   5790 		 */
   5791 		for (i = 0; i < ireq.u.data.length; i++) {
   5792 			if (strcmp(priv[i].name, "monitor_type") == 0) {
   5793 				/*
   5794 				 * Hostap driver, use this one.
   5795 				 * Set monitor mode first.
   5796 				 * You can set it to 0 to get DLT_IEEE80211,
   5797 				 * 1 to get DLT_PRISM, 2 to get
   5798 				 * DLT_IEEE80211_RADIO_AVS, and, with more
   5799 				 * recent versions of the driver, 3 to get
   5800 				 * DLT_IEEE80211_RADIO.
   5801 				 */
   5802 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5803 					break;
   5804 				if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
   5805 					break;
   5806 				if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
   5807 					break;
   5808 				montype = MONITOR_HOSTAP;
   5809 				cmd = priv[i].cmd;
   5810 				break;
   5811 			}
   5812 			if (strcmp(priv[i].name, "set_prismhdr") == 0) {
   5813 				/*
   5814 				 * Prism54 driver, use this one.
   5815 				 * Set monitor mode first.
   5816 				 * You can set it to 2 to get DLT_IEEE80211
   5817 				 * or 3 or get DLT_PRISM.
   5818 				 */
   5819 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5820 					break;
   5821 				if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
   5822 					break;
   5823 				if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
   5824 					break;
   5825 				montype = MONITOR_PRISM54;
   5826 				cmd = priv[i].cmd;
   5827 				break;
   5828 			}
   5829 			if (strcmp(priv[i].name, "forceprismheader") == 0) {
   5830 				/*
   5831 				 * RT2570 driver, use this one.
   5832 				 * Do this after turning monitor mode on.
   5833 				 * You can set it to 1 to get DLT_PRISM or 2
   5834 				 * to get DLT_IEEE80211.
   5835 				 */
   5836 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5837 					break;
   5838 				if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
   5839 					break;
   5840 				if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
   5841 					break;
   5842 				montype = MONITOR_RT2570;
   5843 				cmd = priv[i].cmd;
   5844 				break;
   5845 			}
   5846 			if (strcmp(priv[i].name, "forceprism") == 0) {
   5847 				/*
   5848 				 * RT73 driver, use this one.
   5849 				 * Do this after turning monitor mode on.
   5850 				 * Its argument is a *string*; you can
   5851 				 * set it to "1" to get DLT_PRISM or "2"
   5852 				 * to get DLT_IEEE80211.
   5853 				 */
   5854 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
   5855 					break;
   5856 				if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
   5857 					break;
   5858 				montype = MONITOR_RT73;
   5859 				cmd = priv[i].cmd;
   5860 				break;
   5861 			}
   5862 			if (strcmp(priv[i].name, "prismhdr") == 0) {
   5863 				/*
   5864 				 * One of the RTL8xxx drivers, use this one.
   5865 				 * It can only be done after monitor mode
   5866 				 * has been turned on.  You can set it to 1
   5867 				 * to get DLT_PRISM or 0 to get DLT_IEEE80211.
   5868 				 */
   5869 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5870 					break;
   5871 				if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
   5872 					break;
   5873 				if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
   5874 					break;
   5875 				montype = MONITOR_RTL8XXX;
   5876 				cmd = priv[i].cmd;
   5877 				break;
   5878 			}
   5879 			if (strcmp(priv[i].name, "rfmontx") == 0) {
   5880 				/*
   5881 				 * RT2500 or RT61 driver, use this one.
   5882 				 * It has one one-byte parameter; set
   5883 				 * u.data.length to 1 and u.data.pointer to
   5884 				 * point to the parameter.
   5885 				 * It doesn't itself turn monitor mode on.
   5886 				 * You can set it to 1 to allow transmitting
   5887 				 * in monitor mode(?) and get DLT_IEEE80211,
   5888 				 * or set it to 0 to disallow transmitting in
   5889 				 * monitor mode(?) and get DLT_PRISM.
   5890 				 */
   5891 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5892 					break;
   5893 				if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
   5894 					break;
   5895 				montype = MONITOR_RT2500;
   5896 				cmd = priv[i].cmd;
   5897 				break;
   5898 			}
   5899 			if (strcmp(priv[i].name, "monitor") == 0) {
   5900 				/*
   5901 				 * Either ACX100 or hostap, use this one.
   5902 				 * It turns monitor mode on.
   5903 				 * If it takes two arguments, it's ACX100;
   5904 				 * the first argument is 1 for DLT_PRISM
   5905 				 * or 2 for DLT_IEEE80211, and the second
   5906 				 * argument is the channel on which to
   5907 				 * run.  If it takes one argument, it's
   5908 				 * HostAP, and the argument is 2 for
   5909 				 * DLT_IEEE80211 and 3 for DLT_PRISM.
   5910 				 *
   5911 				 * If we see this, we don't quit, as this
   5912 				 * might be a version of the hostap driver
   5913 				 * that also supports "monitor_type".
   5914 				 */
   5915 				if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
   5916 					break;
   5917 				if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
   5918 					break;
   5919 				switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
   5920 
   5921 				case 1:
   5922 					montype = MONITOR_PRISM;
   5923 					cmd = priv[i].cmd;
   5924 					break;
   5925 
   5926 				case 2:
   5927 					montype = MONITOR_ACX100;
   5928 					cmd = priv[i].cmd;
   5929 					break;
   5930 
   5931 				default:
   5932 					break;
   5933 				}
   5934 			}
   5935 		}
   5936 		free(priv);
   5937 	}
   5938 
   5939 	/*
   5940 	 * XXX - ipw3945?  islism?
   5941 	 */
   5942 
   5943 	/*
   5944 	 * Get the old mode.
   5945 	 */
   5946 	strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   5947 	    sizeof ireq.ifr_ifrn.ifrn_name);
   5948 	if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
   5949 		/*
   5950 		 * We probably won't be able to set the mode, either.
   5951 		 */
   5952 		return PCAP_ERROR_RFMON_NOTSUP;
   5953 	}
   5954 
   5955 	/*
   5956 	 * Is it currently in monitor mode?
   5957 	 */
   5958 	if (ireq.u.mode == IW_MODE_MONITOR) {
   5959 		/*
   5960 		 * Yes.  Just leave things as they are.
   5961 		 * We don't offer multiple link-layer types, as
   5962 		 * changing the link-layer type out from under
   5963 		 * somebody else capturing in monitor mode would
   5964 		 * be considered rude.
   5965 		 */
   5966 		return 1;
   5967 	}
   5968 	/*
   5969 	 * No.  We have to put the adapter into rfmon mode.
   5970 	 */
   5971 
   5972 	/*
   5973 	 * If we haven't already done so, arrange to have
   5974 	 * "pcap_close_all()" called when we exit.
   5975 	 */
   5976 	if (!pcap_do_addexit(handle)) {
   5977 		/*
   5978 		 * "atexit()" failed; don't put the interface
   5979 		 * in rfmon mode, just give up.
   5980 		 */
   5981 		return PCAP_ERROR_RFMON_NOTSUP;
   5982 	}
   5983 
   5984 	/*
   5985 	 * Save the old mode.
   5986 	 */
   5987 	handlep->oldmode = ireq.u.mode;
   5988 
   5989 	/*
   5990 	 * Put the adapter in rfmon mode.  How we do this depends
   5991 	 * on whether we have a special private ioctl or not.
   5992 	 */
   5993 	if (montype == MONITOR_PRISM) {
   5994 		/*
   5995 		 * We have the "monitor" private ioctl, but none of
   5996 		 * the other private ioctls.  Use this, and select
   5997 		 * the Prism header.
   5998 		 *
   5999 		 * If it fails, just fall back on SIOCSIWMODE.
   6000 		 */
   6001 		memset(&ireq, 0, sizeof ireq);
   6002 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6003 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6004 		ireq.u.data.length = 1;	/* 1 argument */
   6005 		args[0] = 3;	/* request Prism header */
   6006 		memcpy(ireq.u.name, args, sizeof (int));
   6007 		if (ioctl(sock_fd, cmd, &ireq) != -1) {
   6008 			/*
   6009 			 * Success.
   6010 			 * Note that we have to put the old mode back
   6011 			 * when we close the device.
   6012 			 */
   6013 			handlep->must_do_on_close |= MUST_CLEAR_RFMON;
   6014 
   6015 			/*
   6016 			 * Add this to the list of pcaps to close
   6017 			 * when we exit.
   6018 			 */
   6019 			pcap_add_to_pcaps_to_close(handle);
   6020 
   6021 			return 1;
   6022 		}
   6023 
   6024 		/*
   6025 		 * Failure.  Fall back on SIOCSIWMODE.
   6026 		 */
   6027 	}
   6028 
   6029 	/*
   6030 	 * First, take the interface down if it's up; otherwise, we
   6031 	 * might get EBUSY.
   6032 	 */
   6033 	memset(&ifr, 0, sizeof(ifr));
   6034 	strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   6035 	if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
   6036 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   6037 		    errno, "%s: Can't get flags", device);
   6038 		return PCAP_ERROR;
   6039 	}
   6040 	oldflags = 0;
   6041 	if (ifr.ifr_flags & IFF_UP) {
   6042 		oldflags = ifr.ifr_flags;
   6043 		ifr.ifr_flags &= ~IFF_UP;
   6044 		if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
   6045 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   6046 			    PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
   6047 			    device);
   6048 			return PCAP_ERROR;
   6049 		}
   6050 	}
   6051 
   6052 	/*
   6053 	 * Then turn monitor mode on.
   6054 	 */
   6055 	strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6056 	    sizeof ireq.ifr_ifrn.ifrn_name);
   6057 	ireq.u.mode = IW_MODE_MONITOR;
   6058 	if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
   6059 		/*
   6060 		 * Scientist, you've failed.
   6061 		 * Bring the interface back up if we shut it down.
   6062 		 */
   6063 		ifr.ifr_flags = oldflags;
   6064 		if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
   6065 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   6066 			    PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
   6067 			    device);
   6068 			return PCAP_ERROR;
   6069 		}
   6070 		return PCAP_ERROR_RFMON_NOTSUP;
   6071 	}
   6072 
   6073 	/*
   6074 	 * XXX - airmon-ng does "iwconfig {if} key off" after setting
   6075 	 * monitor mode and setting the channel, and then does
   6076 	 * "iwconfig up".
   6077 	 */
   6078 
   6079 	/*
   6080 	 * Now select the appropriate radio header.
   6081 	 */
   6082 	switch (montype) {
   6083 
   6084 	case MONITOR_WEXT:
   6085 		/*
   6086 		 * We don't have any private ioctl to set the header.
   6087 		 */
   6088 		break;
   6089 
   6090 	case MONITOR_HOSTAP:
   6091 		/*
   6092 		 * Try to select the radiotap header.
   6093 		 */
   6094 		memset(&ireq, 0, sizeof ireq);
   6095 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6096 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6097 		args[0] = 3;	/* request radiotap header */
   6098 		memcpy(ireq.u.name, args, sizeof (int));
   6099 		if (ioctl(sock_fd, cmd, &ireq) != -1)
   6100 			break;	/* success */
   6101 
   6102 		/*
   6103 		 * That failed.  Try to select the AVS header.
   6104 		 */
   6105 		memset(&ireq, 0, sizeof ireq);
   6106 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6107 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6108 		args[0] = 2;	/* request AVS header */
   6109 		memcpy(ireq.u.name, args, sizeof (int));
   6110 		if (ioctl(sock_fd, cmd, &ireq) != -1)
   6111 			break;	/* success */
   6112 
   6113 		/*
   6114 		 * That failed.  Try to select the Prism header.
   6115 		 */
   6116 		memset(&ireq, 0, sizeof ireq);
   6117 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6118 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6119 		args[0] = 1;	/* request Prism header */
   6120 		memcpy(ireq.u.name, args, sizeof (int));
   6121 		ioctl(sock_fd, cmd, &ireq);
   6122 		break;
   6123 
   6124 	case MONITOR_PRISM:
   6125 		/*
   6126 		 * The private ioctl failed.
   6127 		 */
   6128 		break;
   6129 
   6130 	case MONITOR_PRISM54:
   6131 		/*
   6132 		 * Select the Prism header.
   6133 		 */
   6134 		memset(&ireq, 0, sizeof ireq);
   6135 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6136 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6137 		args[0] = 3;	/* request Prism header */
   6138 		memcpy(ireq.u.name, args, sizeof (int));
   6139 		ioctl(sock_fd, cmd, &ireq);
   6140 		break;
   6141 
   6142 	case MONITOR_ACX100:
   6143 		/*
   6144 		 * Get the current channel.
   6145 		 */
   6146 		memset(&ireq, 0, sizeof ireq);
   6147 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6148 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6149 		if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
   6150 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   6151 			    PCAP_ERRBUF_SIZE, errno, "%s: SIOCGIWFREQ", device);
   6152 			return PCAP_ERROR;
   6153 		}
   6154 		channel = ireq.u.freq.m;
   6155 
   6156 		/*
   6157 		 * Select the Prism header, and set the channel to the
   6158 		 * current value.
   6159 		 */
   6160 		memset(&ireq, 0, sizeof ireq);
   6161 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6162 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6163 		args[0] = 1;		/* request Prism header */
   6164 		args[1] = channel;	/* set channel */
   6165 		memcpy(ireq.u.name, args, 2*sizeof (int));
   6166 		ioctl(sock_fd, cmd, &ireq);
   6167 		break;
   6168 
   6169 	case MONITOR_RT2500:
   6170 		/*
   6171 		 * Disallow transmission - that turns on the
   6172 		 * Prism header.
   6173 		 */
   6174 		memset(&ireq, 0, sizeof ireq);
   6175 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6176 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6177 		args[0] = 0;	/* disallow transmitting */
   6178 		memcpy(ireq.u.name, args, sizeof (int));
   6179 		ioctl(sock_fd, cmd, &ireq);
   6180 		break;
   6181 
   6182 	case MONITOR_RT2570:
   6183 		/*
   6184 		 * Force the Prism header.
   6185 		 */
   6186 		memset(&ireq, 0, sizeof ireq);
   6187 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6188 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6189 		args[0] = 1;	/* request Prism header */
   6190 		memcpy(ireq.u.name, args, sizeof (int));
   6191 		ioctl(sock_fd, cmd, &ireq);
   6192 		break;
   6193 
   6194 	case MONITOR_RT73:
   6195 		/*
   6196 		 * Force the Prism header.
   6197 		 */
   6198 		memset(&ireq, 0, sizeof ireq);
   6199 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6200 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6201 		ireq.u.data.length = 1;	/* 1 argument */
   6202 		ireq.u.data.pointer = "1";
   6203 		ireq.u.data.flags = 0;
   6204 		ioctl(sock_fd, cmd, &ireq);
   6205 		break;
   6206 
   6207 	case MONITOR_RTL8XXX:
   6208 		/*
   6209 		 * Force the Prism header.
   6210 		 */
   6211 		memset(&ireq, 0, sizeof ireq);
   6212 		strlcpy(ireq.ifr_ifrn.ifrn_name, device,
   6213 		    sizeof ireq.ifr_ifrn.ifrn_name);
   6214 		args[0] = 1;	/* request Prism header */
   6215 		memcpy(ireq.u.name, args, sizeof (int));
   6216 		ioctl(sock_fd, cmd, &ireq);
   6217 		break;
   6218 	}
   6219 
   6220 	/*
   6221 	 * Now bring the interface back up if we brought it down.
   6222 	 */
   6223 	if (oldflags != 0) {
   6224 		ifr.ifr_flags = oldflags;
   6225 		if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
   6226 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   6227 			    PCAP_ERRBUF_SIZE, errno, "%s: Can't set flags",
   6228 			    device);
   6229 
   6230 			/*
   6231 			 * At least try to restore the old mode on the
   6232 			 * interface.
   6233 			 */
   6234 			if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
   6235 				/*
   6236 				 * Scientist, you've failed.
   6237 				 */
   6238 				fprintf(stderr,
   6239 				    "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
   6240 				    "Please adjust manually.\n",
   6241 				    strerror(errno));
   6242 			}
   6243 			return PCAP_ERROR;
   6244 		}
   6245 	}
   6246 
   6247 	/*
   6248 	 * Note that we have to put the old mode back when we
   6249 	 * close the device.
   6250 	 */
   6251 	handlep->must_do_on_close |= MUST_CLEAR_RFMON;
   6252 
   6253 	/*
   6254 	 * Add this to the list of pcaps to close when we exit.
   6255 	 */
   6256 	pcap_add_to_pcaps_to_close(handle);
   6257 
   6258 	return 1;
   6259 }
   6260 #endif /* IW_MODE_MONITOR */
   6261 
   6262 /*
   6263  * Try various mechanisms to enter monitor mode.
   6264  */
   6265 static int
   6266 enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
   6267 {
   6268 #if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR)
   6269 	int ret;
   6270 #endif
   6271 
   6272 #ifdef HAVE_LIBNL
   6273 	ret = enter_rfmon_mode_mac80211(handle, sock_fd, device);
   6274 	if (ret < 0)
   6275 		return ret;	/* error attempting to do so */
   6276 	if (ret == 1)
   6277 		return 1;	/* success */
   6278 #endif /* HAVE_LIBNL */
   6279 
   6280 #ifdef IW_MODE_MONITOR
   6281 	ret = enter_rfmon_mode_wext(handle, sock_fd, device);
   6282 	if (ret < 0)
   6283 		return ret;	/* error attempting to do so */
   6284 	if (ret == 1)
   6285 		return 1;	/* success */
   6286 #endif /* IW_MODE_MONITOR */
   6287 
   6288 	/*
   6289 	 * Either none of the mechanisms we know about work or none
   6290 	 * of those mechanisms are available, so we can't do monitor
   6291 	 * mode.
   6292 	 */
   6293 	return 0;
   6294 }
   6295 
   6296 #if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
   6297 /*
   6298  * Map SOF_TIMESTAMPING_ values to PCAP_TSTAMP_ values.
   6299  */
   6300 static const struct {
   6301 	int soft_timestamping_val;
   6302 	int pcap_tstamp_val;
   6303 } sof_ts_type_map[3] = {
   6304 	{ SOF_TIMESTAMPING_SOFTWARE, PCAP_TSTAMP_HOST },
   6305 	{ SOF_TIMESTAMPING_SYS_HARDWARE, PCAP_TSTAMP_ADAPTER },
   6306 	{ SOF_TIMESTAMPING_RAW_HARDWARE, PCAP_TSTAMP_ADAPTER_UNSYNCED }
   6307 };
   6308 #define NUM_SOF_TIMESTAMPING_TYPES	(sizeof sof_ts_type_map / sizeof sof_ts_type_map[0])
   6309 
   6310 /*
   6311  * Set the list of time stamping types to include all types.
   6312  */
   6313 static void
   6314 iface_set_all_ts_types(pcap_t *handle)
   6315 {
   6316 	u_int i;
   6317 
   6318 	handle->tstamp_type_count = NUM_SOF_TIMESTAMPING_TYPES;
   6319 	handle->tstamp_type_list = malloc(NUM_SOF_TIMESTAMPING_TYPES * sizeof(u_int));
   6320 	for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++)
   6321 		handle->tstamp_type_list[i] = sof_ts_type_map[i].pcap_tstamp_val;
   6322 }
   6323 
   6324 #ifdef ETHTOOL_GET_TS_INFO
   6325 /*
   6326  * Get a list of time stamping capabilities.
   6327  */
   6328 static int
   6329 iface_ethtool_get_ts_info(const char *device, pcap_t *handle, char *ebuf)
   6330 {
   6331 	int fd;
   6332 	struct ifreq ifr;
   6333 	struct ethtool_ts_info info;
   6334 	int num_ts_types;
   6335 	u_int i, j;
   6336 
   6337 	/*
   6338 	 * This doesn't apply to the "any" device; you can't say "turn on
   6339 	 * hardware time stamping for all devices that exist now and arrange
   6340 	 * that it be turned on for any device that appears in the future",
   6341 	 * and not all devices even necessarily *support* hardware time
   6342 	 * stamping, so don't report any time stamp types.
   6343 	 */
   6344 	if (strcmp(device, "any") == 0) {
   6345 		handle->tstamp_type_list = NULL;
   6346 		return 0;
   6347 	}
   6348 
   6349 	/*
   6350 	 * Create a socket from which to fetch time stamping capabilities.
   6351 	 */
   6352 	fd = socket(PF_UNIX, SOCK_RAW, 0);
   6353 	if (fd < 0) {
   6354 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6355 		    errno, "socket for SIOCETHTOOL(ETHTOOL_GET_TS_INFO)");
   6356 		return -1;
   6357 	}
   6358 
   6359 	memset(&ifr, 0, sizeof(ifr));
   6360 	strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   6361 	memset(&info, 0, sizeof(info));
   6362 	info.cmd = ETHTOOL_GET_TS_INFO;
   6363 	ifr.ifr_data = (caddr_t)&info;
   6364 	if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
   6365 		int save_errno = errno;
   6366 
   6367 		close(fd);
   6368 		switch (save_errno) {
   6369 
   6370 		case EOPNOTSUPP:
   6371 		case EINVAL:
   6372 			/*
   6373 			 * OK, this OS version or driver doesn't support
   6374 			 * asking for the time stamping types, so let's
   6375 			 * just return all the possible types.
   6376 			 */
   6377 			iface_set_all_ts_types(handle);
   6378 			return 0;
   6379 
   6380 		case ENODEV:
   6381 			/*
   6382 			 * OK, no such device.
   6383 			 * The user will find that out when they try to
   6384 			 * activate the device; just return an empty
   6385 			 * list of time stamp types.
   6386 			 */
   6387 			handle->tstamp_type_list = NULL;
   6388 			return 0;
   6389 
   6390 		default:
   6391 			/*
   6392 			 * Other error.
   6393 			 */
   6394 			pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6395 			    save_errno,
   6396 			    "%s: SIOCETHTOOL(ETHTOOL_GET_TS_INFO) ioctl failed",
   6397 			    device);
   6398 			return -1;
   6399 		}
   6400 	}
   6401 	close(fd);
   6402 
   6403 	/*
   6404 	 * Do we support hardware time stamping of *all* packets?
   6405 	 */
   6406 	if (!(info.rx_filters & (1 << HWTSTAMP_FILTER_ALL))) {
   6407 		/*
   6408 		 * No, so don't report any time stamp types.
   6409 		 *
   6410 		 * XXX - some devices either don't report
   6411 		 * HWTSTAMP_FILTER_ALL when they do support it, or
   6412 		 * report HWTSTAMP_FILTER_ALL but map it to only
   6413 		 * time stamping a few PTP packets.  See
   6414 		 * http://marc.info/?l=linux-netdev&m=146318183529571&w=2
   6415 		 */
   6416 		handle->tstamp_type_list = NULL;
   6417 		return 0;
   6418 	}
   6419 
   6420 	num_ts_types = 0;
   6421 	for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
   6422 		if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val)
   6423 			num_ts_types++;
   6424 	}
   6425 	handle->tstamp_type_count = num_ts_types;
   6426 	if (num_ts_types != 0) {
   6427 		handle->tstamp_type_list = malloc(num_ts_types * sizeof(u_int));
   6428 		for (i = 0, j = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
   6429 			if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val) {
   6430 				handle->tstamp_type_list[j] = sof_ts_type_map[i].pcap_tstamp_val;
   6431 				j++;
   6432 			}
   6433 		}
   6434 	} else
   6435 		handle->tstamp_type_list = NULL;
   6436 
   6437 	return 0;
   6438 }
   6439 #else /* ETHTOOL_GET_TS_INFO */
   6440 static int
   6441 iface_ethtool_get_ts_info(const char *device, pcap_t *handle, char *ebuf _U_)
   6442 {
   6443 	/*
   6444 	 * This doesn't apply to the "any" device; you can't say "turn on
   6445 	 * hardware time stamping for all devices that exist now and arrange
   6446 	 * that it be turned on for any device that appears in the future",
   6447 	 * and not all devices even necessarily *support* hardware time
   6448 	 * stamping, so don't report any time stamp types.
   6449 	 */
   6450 	if (strcmp(device, "any") == 0) {
   6451 		handle->tstamp_type_list = NULL;
   6452 		return 0;
   6453 	}
   6454 
   6455 	/*
   6456 	 * We don't have an ioctl to use to ask what's supported,
   6457 	 * so say we support everything.
   6458 	 */
   6459 	iface_set_all_ts_types(handle);
   6460 	return 0;
   6461 }
   6462 #endif /* ETHTOOL_GET_TS_INFO */
   6463 
   6464 #endif /* defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) */
   6465 
   6466 #ifdef HAVE_PACKET_RING
   6467 /*
   6468  * Find out if we have any form of fragmentation/reassembly offloading.
   6469  *
   6470  * We do so using SIOCETHTOOL checking for various types of offloading;
   6471  * if SIOCETHTOOL isn't defined, or we don't have any #defines for any
   6472  * of the types of offloading, there's nothing we can do to check, so
   6473  * we just say "no, we don't".
   6474  */
   6475 #if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO))
   6476 static int
   6477 iface_ethtool_flag_ioctl(pcap_t *handle, int cmd, const char *cmdname)
   6478 {
   6479 	struct ifreq	ifr;
   6480 	struct ethtool_value eval;
   6481 
   6482 	memset(&ifr, 0, sizeof(ifr));
   6483 	strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
   6484 	eval.cmd = cmd;
   6485 	eval.data = 0;
   6486 	ifr.ifr_data = (caddr_t)&eval;
   6487 	if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) {
   6488 		if (errno == EOPNOTSUPP || errno == EINVAL) {
   6489 			/*
   6490 			 * OK, let's just return 0, which, in our
   6491 			 * case, either means "no, what we're asking
   6492 			 * about is not enabled" or "all the flags
   6493 			 * are clear (i.e., nothing is enabled)".
   6494 			 */
   6495 			return 0;
   6496 		}
   6497 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   6498 		    errno, "%s: SIOCETHTOOL(%s) ioctl failed",
   6499 		    handle->opt.device, cmdname);
   6500 		return -1;
   6501 	}
   6502 	return eval.data;
   6503 }
   6504 
   6505 static int
   6506 iface_get_offload(pcap_t *handle)
   6507 {
   6508 	int ret;
   6509 
   6510 #ifdef ETHTOOL_GTSO
   6511 	ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO");
   6512 	if (ret == -1)
   6513 		return -1;
   6514 	if (ret)
   6515 		return 1;	/* TCP segmentation offloading on */
   6516 #endif
   6517 
   6518 #ifdef ETHTOOL_GUFO
   6519 	ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO");
   6520 	if (ret == -1)
   6521 		return -1;
   6522 	if (ret)
   6523 		return 1;	/* UDP fragmentation offloading on */
   6524 #endif
   6525 
   6526 #ifdef ETHTOOL_GGSO
   6527 	/*
   6528 	 * XXX - will this cause large unsegmented packets to be
   6529 	 * handed to PF_PACKET sockets on transmission?  If not,
   6530 	 * this need not be checked.
   6531 	 */
   6532 	ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO");
   6533 	if (ret == -1)
   6534 		return -1;
   6535 	if (ret)
   6536 		return 1;	/* generic segmentation offloading on */
   6537 #endif
   6538 
   6539 #ifdef ETHTOOL_GFLAGS
   6540 	ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS");
   6541 	if (ret == -1)
   6542 		return -1;
   6543 	if (ret & ETH_FLAG_LRO)
   6544 		return 1;	/* large receive offloading on */
   6545 #endif
   6546 
   6547 #ifdef ETHTOOL_GGRO
   6548 	/*
   6549 	 * XXX - will this cause large reassembled packets to be
   6550 	 * handed to PF_PACKET sockets on receipt?  If not,
   6551 	 * this need not be checked.
   6552 	 */
   6553 	ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO");
   6554 	if (ret == -1)
   6555 		return -1;
   6556 	if (ret)
   6557 		return 1;	/* generic (large) receive offloading on */
   6558 #endif
   6559 
   6560 	return 0;
   6561 }
   6562 #else /* SIOCETHTOOL */
   6563 static int
   6564 iface_get_offload(pcap_t *handle _U_)
   6565 {
   6566 	/*
   6567 	 * XXX - do we need to get this information if we don't
   6568 	 * have the ethtool ioctls?  If so, how do we do that?
   6569 	 */
   6570 	return 0;
   6571 }
   6572 #endif /* SIOCETHTOOL */
   6573 
   6574 #endif /* HAVE_PACKET_RING */
   6575 
   6576 #endif /* HAVE_PF_PACKET_SOCKETS */
   6577 
   6578 /* ===== Functions to interface to the older kernels ================== */
   6579 
   6580 /*
   6581  * Try to open a packet socket using the old kernel interface.
   6582  * Returns 1 on success and a PCAP_ERROR_ value on an error.
   6583  */
   6584 static int
   6585 activate_old(pcap_t *handle)
   6586 {
   6587 	struct pcap_linux *handlep = handle->priv;
   6588 	int		err;
   6589 	int		arptype;
   6590 	struct ifreq	ifr;
   6591 	const char	*device = handle->opt.device;
   6592 	struct utsname	utsname;
   6593 	int		mtu;
   6594 
   6595 	/* Open the socket */
   6596 
   6597 	handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
   6598 	if (handle->fd == -1) {
   6599 		err = errno;
   6600 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   6601 		    err, "socket");
   6602 		if (err == EPERM || err == EACCES) {
   6603 			/*
   6604 			 * You don't have permission to open the
   6605 			 * socket.
   6606 			 */
   6607 			return PCAP_ERROR_PERM_DENIED;
   6608 		} else {
   6609 			/*
   6610 			 * Other error.
   6611 			 */
   6612 			return PCAP_ERROR;
   6613 		}
   6614 	}
   6615 
   6616 	/* It worked - we are using the old interface */
   6617 	handlep->sock_packet = 1;
   6618 
   6619 	/* ...which means we get the link-layer header. */
   6620 	handlep->cooked = 0;
   6621 
   6622 	/* Bind to the given device */
   6623 
   6624 	if (strcmp(device, "any") == 0) {
   6625 		strlcpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
   6626 			PCAP_ERRBUF_SIZE);
   6627 		return PCAP_ERROR;
   6628 	}
   6629 	if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
   6630 		return PCAP_ERROR;
   6631 
   6632 	/*
   6633 	 * Try to get the link-layer type.
   6634 	 */
   6635 	arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
   6636 	if (arptype < 0)
   6637 		return PCAP_ERROR;
   6638 
   6639 	/*
   6640 	 * Try to find the DLT_ type corresponding to that
   6641 	 * link-layer type.
   6642 	 */
   6643 	map_arphrd_to_dlt(handle, handle->fd, arptype, device, 0);
   6644 	if (handle->linktype == -1) {
   6645 		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
   6646 			 "unknown arptype %d", arptype);
   6647 		return PCAP_ERROR;
   6648 	}
   6649 
   6650 	/* Go to promisc mode if requested */
   6651 
   6652 	if (handle->opt.promisc) {
   6653 		memset(&ifr, 0, sizeof(ifr));
   6654 		strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   6655 		if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
   6656 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   6657 			    PCAP_ERRBUF_SIZE, errno, "SIOCGIFFLAGS");
   6658 			return PCAP_ERROR;
   6659 		}
   6660 		if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
   6661 			/*
   6662 			 * Promiscuous mode isn't currently on,
   6663 			 * so turn it on, and remember that
   6664 			 * we should turn it off when the
   6665 			 * pcap_t is closed.
   6666 			 */
   6667 
   6668 			/*
   6669 			 * If we haven't already done so, arrange
   6670 			 * to have "pcap_close_all()" called when
   6671 			 * we exit.
   6672 			 */
   6673 			if (!pcap_do_addexit(handle)) {
   6674 				/*
   6675 				 * "atexit()" failed; don't put
   6676 				 * the interface in promiscuous
   6677 				 * mode, just give up.
   6678 				 */
   6679 				return PCAP_ERROR;
   6680 			}
   6681 
   6682 			ifr.ifr_flags |= IFF_PROMISC;
   6683 			if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
   6684 				pcap_fmt_errmsg_for_errno(handle->errbuf,
   6685 				    PCAP_ERRBUF_SIZE, errno, "SIOCSIFFLAGS");
   6686 				return PCAP_ERROR;
   6687 			}
   6688 			handlep->must_do_on_close |= MUST_CLEAR_PROMISC;
   6689 
   6690 			/*
   6691 			 * Add this to the list of pcaps
   6692 			 * to close when we exit.
   6693 			 */
   6694 			pcap_add_to_pcaps_to_close(handle);
   6695 		}
   6696 	}
   6697 
   6698 	/*
   6699 	 * Compute the buffer size.
   6700 	 *
   6701 	 * We're using SOCK_PACKET, so this might be a 2.0[.x]
   6702 	 * kernel, and might require special handling - check.
   6703 	 */
   6704 	if (uname(&utsname) < 0 ||
   6705 	    strncmp(utsname.release, "2.0", 3) == 0) {
   6706 		/*
   6707 		 * Either we couldn't find out what kernel release
   6708 		 * this is, or it's a 2.0[.x] kernel.
   6709 		 *
   6710 		 * In the 2.0[.x] kernel, a "recvfrom()" on
   6711 		 * a SOCK_PACKET socket, with MSG_TRUNC set, will
   6712 		 * return the number of bytes read, so if we pass
   6713 		 * a length based on the snapshot length, it'll
   6714 		 * return the number of bytes from the packet
   6715 		 * copied to userland, not the actual length
   6716 		 * of the packet.
   6717 		 *
   6718 		 * This means that, for example, the IP dissector
   6719 		 * in tcpdump will get handed a packet length less
   6720 		 * than the length in the IP header, and will
   6721 		 * complain about "truncated-ip".
   6722 		 *
   6723 		 * So we don't bother trying to copy from the
   6724 		 * kernel only the bytes in which we're interested,
   6725 		 * but instead copy them all, just as the older
   6726 		 * versions of libpcap for Linux did.
   6727 		 *
   6728 		 * The buffer therefore needs to be big enough to
   6729 		 * hold the largest packet we can get from this
   6730 		 * device.  Unfortunately, we can't get the MRU
   6731 		 * of the network; we can only get the MTU.  The
   6732 		 * MTU may be too small, in which case a packet larger
   6733 		 * than the buffer size will be truncated *and* we
   6734 		 * won't get the actual packet size.
   6735 		 *
   6736 		 * However, if the snapshot length is larger than
   6737 		 * the buffer size based on the MTU, we use the
   6738 		 * snapshot length as the buffer size, instead;
   6739 		 * this means that with a sufficiently large snapshot
   6740 		 * length we won't artificially truncate packets
   6741 		 * to the MTU-based size.
   6742 		 *
   6743 		 * This mess just one of many problems with packet
   6744 		 * capture on 2.0[.x] kernels; you really want a
   6745 		 * 2.2[.x] or later kernel if you want packet capture
   6746 		 * to work well.
   6747 		 */
   6748 		mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
   6749 		if (mtu == -1)
   6750 			return PCAP_ERROR;
   6751 		handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
   6752 		if (handle->bufsize < (u_int)handle->snapshot)
   6753 			handle->bufsize = (u_int)handle->snapshot;
   6754 	} else {
   6755 		/*
   6756 		 * This is a 2.2[.x] or later kernel.
   6757 		 *
   6758 		 * We can safely pass "recvfrom()" a byte count
   6759 		 * based on the snapshot length.
   6760 		 */
   6761 		handle->bufsize = (u_int)handle->snapshot;
   6762 	}
   6763 
   6764 	/*
   6765 	 * Default value for offset to align link-layer payload
   6766 	 * on a 4-byte boundary.
   6767 	 */
   6768 	handle->offset	 = 0;
   6769 
   6770 	/*
   6771 	 * SOCK_PACKET sockets don't supply information from
   6772 	 * stripped VLAN tags.
   6773 	 */
   6774 	handlep->vlan_offset = -1; /* unknown */
   6775 
   6776 	return 1;
   6777 }
   6778 
   6779 /*
   6780  *  Bind the socket associated with FD to the given device using the
   6781  *  interface of the old kernels.
   6782  */
   6783 static int
   6784 iface_bind_old(int fd, const char *device, char *ebuf)
   6785 {
   6786 	struct sockaddr	saddr;
   6787 	int		err;
   6788 	socklen_t	errlen = sizeof(err);
   6789 
   6790 	memset(&saddr, 0, sizeof(saddr));
   6791 	strlcpy(saddr.sa_data, device, sizeof(saddr.sa_data));
   6792 	if (bind(fd, &saddr, sizeof(saddr)) == -1) {
   6793 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6794 		    errno, "bind");
   6795 		return -1;
   6796 	}
   6797 
   6798 	/* Any pending errors, e.g., network is down? */
   6799 
   6800 	if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
   6801 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6802 		    errno, "getsockopt");
   6803 		return -1;
   6804 	}
   6805 
   6806 	if (err > 0) {
   6807 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6808 		    err, "bind");
   6809 		return -1;
   6810 	}
   6811 
   6812 	return 0;
   6813 }
   6814 
   6815 
   6816 /* ===== System calls available on all supported kernels ============== */
   6817 
   6818 /*
   6819  *  Query the kernel for the MTU of the given interface.
   6820  */
   6821 static int
   6822 iface_get_mtu(int fd, const char *device, char *ebuf)
   6823 {
   6824 	struct ifreq	ifr;
   6825 
   6826 	if (!device)
   6827 		return BIGGER_THAN_ALL_MTUS;
   6828 
   6829 	memset(&ifr, 0, sizeof(ifr));
   6830 	strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   6831 
   6832 	if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
   6833 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6834 		    errno, "SIOCGIFMTU");
   6835 		return -1;
   6836 	}
   6837 
   6838 	return ifr.ifr_mtu;
   6839 }
   6840 
   6841 /*
   6842  *  Get the hardware type of the given interface as ARPHRD_xxx constant.
   6843  */
   6844 static int
   6845 iface_get_arptype(int fd, const char *device, char *ebuf)
   6846 {
   6847 	struct ifreq	ifr;
   6848 
   6849 	memset(&ifr, 0, sizeof(ifr));
   6850 	strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
   6851 
   6852 	if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
   6853 		pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
   6854 		    errno, "SIOCGIFHWADDR");
   6855 		if (errno == ENODEV) {
   6856 			/*
   6857 			 * No such device.
   6858 			 */
   6859 			return PCAP_ERROR_NO_SUCH_DEVICE;
   6860 		}
   6861 		return PCAP_ERROR;
   6862 	}
   6863 
   6864 	return ifr.ifr_hwaddr.sa_family;
   6865 }
   6866 
   6867 #ifdef SO_ATTACH_FILTER
   6868 static int
   6869 fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped)
   6870 {
   6871 	struct pcap_linux *handlep = handle->priv;
   6872 	size_t prog_size;
   6873 	register int i;
   6874 	register struct bpf_insn *p;
   6875 	struct bpf_insn *f;
   6876 	int len;
   6877 
   6878 	/*
   6879 	 * Make a copy of the filter, and modify that copy if
   6880 	 * necessary.
   6881 	 */
   6882 	prog_size = sizeof(*handle->fcode.bf_insns) * handle->fcode.bf_len;
   6883 	len = handle->fcode.bf_len;
   6884 	f = (struct bpf_insn *)malloc(prog_size);
   6885 	if (f == NULL) {
   6886 		pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
   6887 		    errno, "malloc");
   6888 		return -1;
   6889 	}
   6890 	memcpy(f, handle->fcode.bf_insns, prog_size);
   6891 	fcode->len = len;
   6892 	fcode->filter = (struct sock_filter *) f;
   6893 
   6894 	for (i = 0; i < len; ++i) {
   6895 		p = &f[i];
   6896 		/*
   6897 		 * What type of instruction is this?
   6898 		 */
   6899 		switch (BPF_CLASS(p->code)) {
   6900 
   6901 		case BPF_RET:
   6902 			/*
   6903 			 * It's a return instruction; are we capturing
   6904 			 * in memory-mapped mode?
   6905 			 */
   6906 			if (!is_mmapped) {
   6907 				/*
   6908 				 * No; is the snapshot length a constant,
   6909 				 * rather than the contents of the
   6910 				 * accumulator?
   6911 				 */
   6912 				if (BPF_MODE(p->code) == BPF_K) {
   6913 					/*
   6914 					 * Yes - if the value to be returned,
   6915 					 * i.e. the snapshot length, is
   6916 					 * anything other than 0, make it
   6917 					 * MAXIMUM_SNAPLEN, so that the packet
   6918 					 * is truncated by "recvfrom()",
   6919 					 * not by the filter.
   6920 					 *
   6921 					 * XXX - there's nothing we can
   6922 					 * easily do if it's getting the
   6923 					 * value from the accumulator; we'd
   6924 					 * have to insert code to force
   6925 					 * non-zero values to be
   6926 					 * MAXIMUM_SNAPLEN.
   6927 					 */
   6928 					if (p->k != 0)
   6929 						p->k = MAXIMUM_SNAPLEN;
   6930 				}
   6931 			}
   6932 			break;
   6933 
   6934 		case BPF_LD:
   6935 		case BPF_LDX:
   6936 			/*
   6937 			 * It's a load instruction; is it loading
   6938 			 * from the packet?
   6939 			 */
   6940 			switch (BPF_MODE(p->code)) {
   6941 
   6942 			case BPF_ABS:
   6943 			case BPF_IND:
   6944 			case BPF_MSH:
   6945 				/*
   6946 				 * Yes; are we in cooked mode?
   6947 				 */
   6948 				if (handlep->cooked) {
   6949 					/*
   6950 					 * Yes, so we need to fix this
   6951 					 * instruction.
   6952 					 */
   6953 					if (fix_offset(p) < 0) {
   6954 						/*
   6955 						 * We failed to do so.
   6956 						 * Return 0, so our caller
   6957 						 * knows to punt to userland.
   6958 						 */
   6959 						return 0;
   6960 					}
   6961 				}
   6962 				break;
   6963 			}
   6964 			break;
   6965 		}
   6966 	}
   6967 	return 1;	/* we succeeded */
   6968 }
   6969 
   6970 static int
   6971 fix_offset(struct bpf_insn *p)
   6972 {
   6973 	/*
   6974 	 * What's the offset?
   6975 	 */
   6976 	if (p->k >= SLL_HDR_LEN) {
   6977 		/*
   6978 		 * It's within the link-layer payload; that starts at an
   6979 		 * offset of 0, as far as the kernel packet filter is
   6980 		 * concerned, so subtract the length of the link-layer
   6981 		 * header.
   6982 		 */
   6983 		p->k -= SLL_HDR_LEN;
   6984 	} else if (p->k == 0) {
   6985 		/*
   6986 		 * It's the packet type field; map it to the special magic
   6987 		 * kernel offset for that field.
   6988 		 */
   6989 		p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
   6990 	} else if (p->k == 14) {
   6991 		/*
   6992 		 * It's the protocol field; map it to the special magic
   6993 		 * kernel offset for that field.
   6994 		 */
   6995 		p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
   6996 	} else if ((bpf_int32)(p->k) > 0) {
   6997 		/*
   6998 		 * It's within the header, but it's not one of those
   6999 		 * fields; we can't do that in the kernel, so punt
   7000 		 * to userland.
   7001 		 */
   7002 		return -1;
   7003 	}
   7004 	return 0;
   7005 }
   7006 
   7007 static int
   7008 set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode)
   7009 {
   7010 	int total_filter_on = 0;
   7011 	int save_mode;
   7012 	int ret;
   7013 	int save_errno;
   7014 
   7015 	/*
   7016 	 * The socket filter code doesn't discard all packets queued
   7017 	 * up on the socket when the filter is changed; this means
   7018 	 * that packets that don't match the new filter may show up
   7019 	 * after the new filter is put onto the socket, if those
   7020 	 * packets haven't yet been read.
   7021 	 *
   7022 	 * This means, for example, that if you do a tcpdump capture
   7023 	 * with a filter, the first few packets in the capture might
   7024 	 * be packets that wouldn't have passed the filter.
   7025 	 *
   7026 	 * We therefore discard all packets queued up on the socket
   7027 	 * when setting a kernel filter.  (This isn't an issue for
   7028 	 * userland filters, as the userland filtering is done after
   7029 	 * packets are queued up.)
   7030 	 *
   7031 	 * To flush those packets, we put the socket in read-only mode,
   7032 	 * and read packets from the socket until there are no more to
   7033 	 * read.
   7034 	 *
   7035 	 * In order to keep that from being an infinite loop - i.e.,
   7036 	 * to keep more packets from arriving while we're draining
   7037 	 * the queue - we put the "total filter", which is a filter
   7038 	 * that rejects all packets, onto the socket before draining
   7039 	 * the queue.
   7040 	 *
   7041 	 * This code deliberately ignores any errors, so that you may
   7042 	 * get bogus packets if an error occurs, rather than having
   7043 	 * the filtering done in userland even if it could have been
   7044 	 * done in the kernel.
   7045 	 */
   7046 	if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
   7047 		       &total_fcode, sizeof(total_fcode)) == 0) {
   7048 		char drain[1];
   7049 
   7050 		/*
   7051 		 * Note that we've put the total filter onto the socket.
   7052 		 */
   7053 		total_filter_on = 1;
   7054 
   7055 		/*
   7056 		 * Save the socket's current mode, and put it in
   7057 		 * non-blocking mode; we drain it by reading packets
   7058 		 * until we get an error (which is normally a
   7059 		 * "nothing more to be read" error).
   7060 		 */
   7061 		save_mode = fcntl(handle->fd, F_GETFL, 0);
   7062 		if (save_mode == -1) {
   7063 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   7064 			    PCAP_ERRBUF_SIZE, errno,
   7065 			    "can't get FD flags when changing filter");
   7066 			return -2;
   7067 		}
   7068 		if (fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) < 0) {
   7069 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   7070 			    PCAP_ERRBUF_SIZE, errno,
   7071 			    "can't set nonblocking mode when changing filter");
   7072 			return -2;
   7073 		}
   7074 		while (recv(handle->fd, &drain, sizeof drain, MSG_TRUNC) >= 0)
   7075 			;
   7076 		save_errno = errno;
   7077 		if (save_errno != EAGAIN) {
   7078 			/*
   7079 			 * Fatal error.
   7080 			 *
   7081 			 * If we can't restore the mode or reset the
   7082 			 * kernel filter, there's nothing we can do.
   7083 			 */
   7084 			(void)fcntl(handle->fd, F_SETFL, save_mode);
   7085 			(void)reset_kernel_filter(handle);
   7086 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   7087 			    PCAP_ERRBUF_SIZE, save_errno,
   7088 			    "recv failed when changing filter");
   7089 			return -2;
   7090 		}
   7091 		if (fcntl(handle->fd, F_SETFL, save_mode) == -1) {
   7092 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   7093 			    PCAP_ERRBUF_SIZE, errno,
   7094 			    "can't restore FD flags when changing filter");
   7095 			return -2;
   7096 		}
   7097 	}
   7098 
   7099 	/*
   7100 	 * Now attach the new filter.
   7101 	 */
   7102 	ret = setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
   7103 			 fcode, sizeof(*fcode));
   7104 	if (ret == -1 && total_filter_on) {
   7105 		/*
   7106 		 * Well, we couldn't set that filter on the socket,
   7107 		 * but we could set the total filter on the socket.
   7108 		 *
   7109 		 * This could, for example, mean that the filter was
   7110 		 * too big to put into the kernel, so we'll have to
   7111 		 * filter in userland; in any case, we'll be doing
   7112 		 * filtering in userland, so we need to remove the
   7113 		 * total filter so we see packets.
   7114 		 */
   7115 		save_errno = errno;
   7116 
   7117 		/*
   7118 		 * If this fails, we're really screwed; we have the
   7119 		 * total filter on the socket, and it won't come off.
   7120 		 * Report it as a fatal error.
   7121 		 */
   7122 		if (reset_kernel_filter(handle) == -1) {
   7123 			pcap_fmt_errmsg_for_errno(handle->errbuf,
   7124 			    PCAP_ERRBUF_SIZE, errno,
   7125 			    "can't remove kernel total filter");
   7126 			return -2;	/* fatal error */
   7127 		}
   7128 
   7129 		errno = save_errno;
   7130 	}
   7131 	return ret;
   7132 }
   7133 
   7134 static int
   7135 reset_kernel_filter(pcap_t *handle)
   7136 {
   7137 	int ret;
   7138 	/*
   7139 	 * setsockopt() barfs unless it get a dummy parameter.
   7140 	 * valgrind whines unless the value is initialized,
   7141 	 * as it has no idea that setsockopt() ignores its
   7142 	 * parameter.
   7143 	 */
   7144 	int dummy = 0;
   7145 
   7146 	ret = setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
   7147 				   &dummy, sizeof(dummy));
   7148 	/*
   7149 	 * Ignore ENOENT - it means "we don't have a filter", so there
   7150 	 * was no filter to remove, and there's still no filter.
   7151 	 *
   7152 	 * Also ignore ENONET, as a lot of kernel versions had a
   7153 	 * typo where ENONET, rather than ENOENT, was returned.
   7154 	 */
   7155 	if (ret == -1 && errno != ENOENT && errno != ENONET)
   7156 		return -1;
   7157 	return 0;
   7158 }
   7159 #endif
   7160 
   7161 int
   7162 pcap_set_protocol_linux(pcap_t *p, int protocol)
   7163 {
   7164 	if (pcap_check_activated(p))
   7165 		return (PCAP_ERROR_ACTIVATED);
   7166 	p->opt.protocol = protocol;
   7167 	return (0);
   7168 }
   7169 
   7170 /*
   7171  * Libpcap version string.
   7172  */
   7173 const char *
   7174 pcap_lib_version(void)
   7175 {
   7176 #ifdef HAVE_PACKET_RING
   7177  #if defined(HAVE_TPACKET3)
   7178 	return (PCAP_VERSION_STRING " (with TPACKET_V3)");
   7179  #elif defined(HAVE_TPACKET2)
   7180 	return (PCAP_VERSION_STRING " (with TPACKET_V2)");
   7181  #else
   7182 	return (PCAP_VERSION_STRING " (with TPACKET_V1)");
   7183  #endif
   7184 #else
   7185 	return (PCAP_VERSION_STRING " (without TPACKET)");
   7186 #endif
   7187 }
   7188