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      1 /*
      2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that: (1) source code distributions
      7  * retain the above copyright notice and this paragraph in its entirety, (2)
      8  * distributions including binary code include the above copyright notice and
      9  * this paragraph in its entirety in the documentation or other materials
     10  * provided with the distribution, and (3) all advertising materials mentioning
     11  * features or use of this software display the following acknowledgement:
     12  * ``This product includes software developed by the University of California,
     13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
     14  * the University nor the names of its contributors may be used to endorse
     15  * or promote products derived from this software without specific prior
     16  * written permission.
     17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
     18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
     19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
     20  *
     21  * pcap-common.c - common code for pcap and pcap-ng files
     22  */
     23 
     24 #ifdef HAVE_CONFIG_H
     25 #include "config.h"
     26 #endif
     27 
     28 #ifdef _WIN32
     29 #include <pcap-stdinc.h>
     30 #else /* _WIN32 */
     31 #if HAVE_INTTYPES_H
     32 #include <inttypes.h>
     33 #elif HAVE_STDINT_H
     34 #include <stdint.h>
     35 #endif
     36 #ifdef HAVE_SYS_BITYPES_H
     37 #include <sys/bitypes.h>
     38 #endif
     39 #include <sys/types.h>
     40 #endif /* _WIN32 */
     41 
     42 #include "pcap-int.h"
     43 #include "extract.h"
     44 #include "pcap/sll.h"
     45 #include "pcap/usb.h"
     46 #include "pcap/nflog.h"
     47 #include "pcap/can_socketcan.h"
     48 
     49 #include "pcap-common.h"
     50 
     51 /*
     52  * We don't write DLT_* values to capture files, because they're not the
     53  * same on all platforms.
     54  *
     55  * Unfortunately, the various flavors of BSD have not always used the same
     56  * numerical values for the same data types, and various patches to
     57  * libpcap for non-BSD OSes have added their own DLT_* codes for link
     58  * layer encapsulation types seen on those OSes, and those codes have had,
     59  * in some cases, values that were also used, on other platforms, for other
     60  * link layer encapsulation types.
     61  *
     62  * This means that capture files of a type whose numerical DLT_* code
     63  * means different things on different BSDs, or with different versions
     64  * of libpcap, can't always be read on systems other than those like
     65  * the one running on the machine on which the capture was made.
     66  *
     67  * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
     68  * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
     69  * codes to DLT_* codes when reading a savefile header.
     70  *
     71  * For those DLT_* codes that have, as far as we know, the same values on
     72  * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
     73  * DLT_xxx; that way, captures of those types can still be read by
     74  * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
     75  * captures of those types written by versions of libpcap that map DLT_
     76  * values to LINKTYPE_ values can still be read by older versions
     77  * of libpcap.
     78  *
     79  * The other LINKTYPE_* codes are given values starting at 100, in the
     80  * hopes that no DLT_* code will be given one of those values.
     81  *
     82  * In order to ensure that a given LINKTYPE_* code's value will refer to
     83  * the same encapsulation type on all platforms, you should not allocate
     84  * a new LINKTYPE_* value without consulting
     85  * "tcpdump-workers (at) lists.tcpdump.org".  The tcpdump developers will
     86  * allocate a value for you, and will not subsequently allocate it to
     87  * anybody else; that value will be added to the "pcap.h" in the
     88  * tcpdump.org Git repository, so that a future libpcap release will
     89  * include it.
     90  *
     91  * You should, if possible, also contribute patches to libpcap and tcpdump
     92  * to handle the new encapsulation type, so that they can also be checked
     93  * into the tcpdump.org Git repository and so that they will appear in
     94  * future libpcap and tcpdump releases.
     95  *
     96  * Do *NOT* assume that any values after the largest value in this file
     97  * are available; you might not have the most up-to-date version of this
     98  * file, and new values after that one might have been assigned.  Also,
     99  * do *NOT* use any values below 100 - those might already have been
    100  * taken by one (or more!) organizations.
    101  *
    102  * Any platform that defines additional DLT_* codes should:
    103  *
    104  *	request a LINKTYPE_* code and value from tcpdump.org,
    105  *	as per the above;
    106  *
    107  *	add, in their version of libpcap, an entry to map
    108  *	those DLT_* codes to the corresponding LINKTYPE_*
    109  *	code;
    110  *
    111  *	redefine, in their "net/bpf.h", any DLT_* values
    112  *	that collide with the values used by their additional
    113  *	DLT_* codes, to remove those collisions (but without
    114  *	making them collide with any of the LINKTYPE_*
    115  *	values equal to 50 or above; they should also avoid
    116  *	defining DLT_* values that collide with those
    117  *	LINKTYPE_* values, either).
    118  */
    119 #define LINKTYPE_NULL		DLT_NULL
    120 #define LINKTYPE_ETHERNET	DLT_EN10MB	/* also for 100Mb and up */
    121 #define LINKTYPE_EXP_ETHERNET	DLT_EN3MB	/* 3Mb experimental Ethernet */
    122 #define LINKTYPE_AX25		DLT_AX25
    123 #define LINKTYPE_PRONET		DLT_PRONET
    124 #define LINKTYPE_CHAOS		DLT_CHAOS
    125 #define LINKTYPE_IEEE802_5	DLT_IEEE802	/* DLT_IEEE802 is used for 802.5 Token Ring */
    126 #define LINKTYPE_ARCNET_BSD	DLT_ARCNET	/* BSD-style headers */
    127 #define LINKTYPE_SLIP		DLT_SLIP
    128 #define LINKTYPE_PPP		DLT_PPP
    129 #define LINKTYPE_FDDI		DLT_FDDI
    130 
    131 /*
    132  * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
    133  * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
    134  * field) at the beginning of the packet.
    135  *
    136  * This is for use when there is always such a header; the address field
    137  * might be 0xff, for regular PPP, or it might be an address field for Cisco
    138  * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
    139  * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
    140  *
    141  * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
    142  * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
    143  * captures will be written out with a link type that NetBSD's tcpdump
    144  * can read.
    145  */
    146 #define LINKTYPE_PPP_HDLC	50		/* PPP in HDLC-like framing */
    147 
    148 #define LINKTYPE_PPP_ETHER	51		/* NetBSD PPP-over-Ethernet */
    149 
    150 #define LINKTYPE_SYMANTEC_FIREWALL 99		/* Symantec Enterprise Firewall */
    151 
    152 /*
    153  * These correspond to DLT_s that have different values on different
    154  * platforms; we map between these values in capture files and
    155  * the DLT_ values as returned by pcap_datalink() and passed to
    156  * pcap_open_dead().
    157  */
    158 #define LINKTYPE_ATM_RFC1483	100		/* LLC/SNAP-encapsulated ATM */
    159 #define LINKTYPE_RAW		101		/* raw IP */
    160 #define LINKTYPE_SLIP_BSDOS	102		/* BSD/OS SLIP BPF header */
    161 #define LINKTYPE_PPP_BSDOS	103		/* BSD/OS PPP BPF header */
    162 
    163 /*
    164  * Values starting with 104 are used for newly-assigned link-layer
    165  * header type values; for those link-layer header types, the DLT_
    166  * value returned by pcap_datalink() and passed to pcap_open_dead(),
    167  * and the LINKTYPE_ value that appears in capture files, are the
    168  * same.
    169  *
    170  * LINKTYPE_MATCHING_MIN is the lowest such value; LINKTYPE_MATCHING_MAX
    171  * is the highest such value.
    172  */
    173 #define LINKTYPE_MATCHING_MIN	104		/* lowest value in the "matching" range */
    174 
    175 #define LINKTYPE_C_HDLC		104		/* Cisco HDLC */
    176 #define LINKTYPE_IEEE802_11	105		/* IEEE 802.11 (wireless) */
    177 #define LINKTYPE_ATM_CLIP	106		/* Linux Classical IP over ATM */
    178 #define LINKTYPE_FRELAY		107		/* Frame Relay */
    179 #define LINKTYPE_LOOP		108		/* OpenBSD loopback */
    180 #define LINKTYPE_ENC		109		/* OpenBSD IPSEC enc */
    181 
    182 /*
    183  * These three types are reserved for future use.
    184  */
    185 #define LINKTYPE_LANE8023	110		/* ATM LANE + 802.3 */
    186 #define LINKTYPE_HIPPI		111		/* NetBSD HIPPI */
    187 #define LINKTYPE_HDLC		112		/* NetBSD HDLC framing */
    188 
    189 #define LINKTYPE_LINUX_SLL	113		/* Linux cooked socket capture */
    190 #define LINKTYPE_LTALK		114		/* Apple LocalTalk hardware */
    191 #define LINKTYPE_ECONET		115		/* Acorn Econet */
    192 
    193 /*
    194  * Reserved for use with OpenBSD ipfilter.
    195  */
    196 #define LINKTYPE_IPFILTER	116
    197 
    198 #define LINKTYPE_PFLOG		117		/* OpenBSD DLT_PFLOG */
    199 #define LINKTYPE_CISCO_IOS	118		/* For Cisco-internal use */
    200 #define LINKTYPE_IEEE802_11_PRISM 119		/* 802.11 plus Prism II monitor mode radio metadata header */
    201 #define LINKTYPE_IEEE802_11_AIRONET 120		/* 802.11 plus FreeBSD Aironet driver radio metadata header */
    202 
    203 /*
    204  * Reserved for Siemens HiPath HDLC.
    205  */
    206 #define LINKTYPE_HHDLC		121
    207 
    208 #define LINKTYPE_IP_OVER_FC	122		/* RFC 2625 IP-over-Fibre Channel */
    209 #define LINKTYPE_SUNATM		123		/* Solaris+SunATM */
    210 
    211 /*
    212  * Reserved as per request from Kent Dahlgren <kent (at) praesum.com>
    213  * for private use.
    214  */
    215 #define LINKTYPE_RIO		124		/* RapidIO */
    216 #define LINKTYPE_PCI_EXP	125		/* PCI Express */
    217 #define LINKTYPE_AURORA		126		/* Xilinx Aurora link layer */
    218 
    219 #define LINKTYPE_IEEE802_11_RADIOTAP 127	/* 802.11 plus radiotap radio metadata header */
    220 
    221 /*
    222  * Reserved for the TZSP encapsulation, as per request from
    223  * Chris Waters <chris.waters (at) networkchemistry.com>
    224  * TZSP is a generic encapsulation for any other link type,
    225  * which includes a means to include meta-information
    226  * with the packet, e.g. signal strength and channel
    227  * for 802.11 packets.
    228  */
    229 #define LINKTYPE_TZSP		128		/* Tazmen Sniffer Protocol */
    230 
    231 #define LINKTYPE_ARCNET_LINUX	129		/* Linux-style headers */
    232 
    233 /*
    234  * Juniper-private data link types, as per request from
    235  * Hannes Gredler <hannes (at) juniper.net>.  The corresponding
    236  * DLT_s are used for passing on chassis-internal
    237  * metainformation such as QOS profiles, etc..
    238  */
    239 #define LINKTYPE_JUNIPER_MLPPP  130
    240 #define LINKTYPE_JUNIPER_MLFR   131
    241 #define LINKTYPE_JUNIPER_ES     132
    242 #define LINKTYPE_JUNIPER_GGSN   133
    243 #define LINKTYPE_JUNIPER_MFR    134
    244 #define LINKTYPE_JUNIPER_ATM2   135
    245 #define LINKTYPE_JUNIPER_SERVICES 136
    246 #define LINKTYPE_JUNIPER_ATM1   137
    247 
    248 #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138	/* Apple IP-over-IEEE 1394 cooked header */
    249 
    250 #define LINKTYPE_MTP2_WITH_PHDR	139
    251 #define LINKTYPE_MTP2		140
    252 #define LINKTYPE_MTP3		141
    253 #define LINKTYPE_SCCP		142
    254 
    255 #define LINKTYPE_DOCSIS		143		/* DOCSIS MAC frames */
    256 
    257 #define LINKTYPE_LINUX_IRDA	144		/* Linux-IrDA */
    258 
    259 /*
    260  * Reserved for IBM SP switch and IBM Next Federation switch.
    261  */
    262 #define LINKTYPE_IBM_SP		145
    263 #define LINKTYPE_IBM_SN		146
    264 
    265 /*
    266  * Reserved for private use.  If you have some link-layer header type
    267  * that you want to use within your organization, with the capture files
    268  * using that link-layer header type not ever be sent outside your
    269  * organization, you can use these values.
    270  *
    271  * No libpcap release will use these for any purpose, nor will any
    272  * tcpdump release use them, either.
    273  *
    274  * Do *NOT* use these in capture files that you expect anybody not using
    275  * your private versions of capture-file-reading tools to read; in
    276  * particular, do *NOT* use them in products, otherwise you may find that
    277  * people won't be able to use tcpdump, or snort, or Ethereal, or... to
    278  * read capture files from your firewall/intrusion detection/traffic
    279  * monitoring/etc. appliance, or whatever product uses that LINKTYPE_ value,
    280  * and you may also find that the developers of those applications will
    281  * not accept patches to let them read those files.
    282  *
    283  * Also, do not use them if somebody might send you a capture using them
    284  * for *their* private type and tools using them for *your* private type
    285  * would have to read them.
    286  *
    287  * Instead, in those cases, ask "tcpdump-workers (at) lists.tcpdump.org" for a
    288  * new DLT_ and LINKTYPE_ value, as per the comment in pcap/bpf.h, and use
    289  * the type you're given.
    290  */
    291 #define LINKTYPE_USER0		147
    292 #define LINKTYPE_USER1		148
    293 #define LINKTYPE_USER2		149
    294 #define LINKTYPE_USER3		150
    295 #define LINKTYPE_USER4		151
    296 #define LINKTYPE_USER5		152
    297 #define LINKTYPE_USER6		153
    298 #define LINKTYPE_USER7		154
    299 #define LINKTYPE_USER8		155
    300 #define LINKTYPE_USER9		156
    301 #define LINKTYPE_USER10		157
    302 #define LINKTYPE_USER11		158
    303 #define LINKTYPE_USER12		159
    304 #define LINKTYPE_USER13		160
    305 #define LINKTYPE_USER14		161
    306 #define LINKTYPE_USER15		162
    307 
    308 /*
    309  * For future use with 802.11 captures - defined by AbsoluteValue
    310  * Systems to store a number of bits of link-layer information
    311  * including radio information:
    312  *
    313  *	http://www.shaftnet.org/~pizza/software/capturefrm.txt
    314  */
    315 #define LINKTYPE_IEEE802_11_AVS	163	/* 802.11 plus AVS radio metadata header */
    316 
    317 /*
    318  * Juniper-private data link type, as per request from
    319  * Hannes Gredler <hannes (at) juniper.net>.  The corresponding
    320  * DLT_s are used for passing on chassis-internal
    321  * metainformation such as QOS profiles, etc..
    322  */
    323 #define LINKTYPE_JUNIPER_MONITOR 164
    324 
    325 /*
    326  * BACnet MS/TP frames.
    327  */
    328 #define LINKTYPE_BACNET_MS_TP	165
    329 
    330 /*
    331  * Another PPP variant as per request from Karsten Keil <kkeil (at) suse.de>.
    332  *
    333  * This is used in some OSes to allow a kernel socket filter to distinguish
    334  * between incoming and outgoing packets, on a socket intended to
    335  * supply pppd with outgoing packets so it can do dial-on-demand and
    336  * hangup-on-lack-of-demand; incoming packets are filtered out so they
    337  * don't cause pppd to hold the connection up (you don't want random
    338  * input packets such as port scans, packets from old lost connections,
    339  * etc. to force the connection to stay up).
    340  *
    341  * The first byte of the PPP header (0xff03) is modified to accomodate
    342  * the direction - 0x00 = IN, 0x01 = OUT.
    343  */
    344 #define LINKTYPE_PPP_PPPD	166
    345 
    346 /*
    347  * Juniper-private data link type, as per request from
    348  * Hannes Gredler <hannes (at) juniper.net>.  The DLT_s are used
    349  * for passing on chassis-internal metainformation such as
    350  * QOS profiles, cookies, etc..
    351  */
    352 #define LINKTYPE_JUNIPER_PPPOE     167
    353 #define LINKTYPE_JUNIPER_PPPOE_ATM 168
    354 
    355 #define LINKTYPE_GPRS_LLC	169		/* GPRS LLC */
    356 #define LINKTYPE_GPF_T		170		/* GPF-T (ITU-T G.7041/Y.1303) */
    357 #define LINKTYPE_GPF_F		171		/* GPF-F (ITU-T G.7041/Y.1303) */
    358 
    359 /*
    360  * Requested by Oolan Zimmer <oz (at) gcom.com> for use in Gcom's T1/E1 line
    361  * monitoring equipment.
    362  */
    363 #define LINKTYPE_GCOM_T1E1	172
    364 #define LINKTYPE_GCOM_SERIAL	173
    365 
    366 /*
    367  * Juniper-private data link type, as per request from
    368  * Hannes Gredler <hannes (at) juniper.net>.  The DLT_ is used
    369  * for internal communication to Physical Interface Cards (PIC)
    370  */
    371 #define LINKTYPE_JUNIPER_PIC_PEER    174
    372 
    373 /*
    374  * Link types requested by Gregor Maier <gregor (at) endace.com> of Endace
    375  * Measurement Systems.  They add an ERF header (see
    376  * http://www.endace.com/support/EndaceRecordFormat.pdf) in front of
    377  * the link-layer header.
    378  */
    379 #define LINKTYPE_ERF_ETH	175	/* Ethernet */
    380 #define LINKTYPE_ERF_POS	176	/* Packet-over-SONET */
    381 
    382 /*
    383  * Requested by Daniele Orlandi <daniele (at) orlandi.com> for raw LAPD
    384  * for vISDN (http://www.orlandi.com/visdn/).  Its link-layer header
    385  * includes additional information before the LAPD header, so it's
    386  * not necessarily a generic LAPD header.
    387  */
    388 #define LINKTYPE_LINUX_LAPD	177
    389 
    390 /*
    391  * Juniper-private data link type, as per request from
    392  * Hannes Gredler <hannes (at) juniper.net>.
    393  * The Link Types are used for prepending meta-information
    394  * like interface index, interface name
    395  * before standard Ethernet, PPP, Frelay & C-HDLC Frames
    396  */
    397 #define LINKTYPE_JUNIPER_ETHER  178
    398 #define LINKTYPE_JUNIPER_PPP    179
    399 #define LINKTYPE_JUNIPER_FRELAY 180
    400 #define LINKTYPE_JUNIPER_CHDLC  181
    401 
    402 /*
    403  * Multi Link Frame Relay (FRF.16)
    404  */
    405 #define LINKTYPE_MFR            182
    406 
    407 /*
    408  * Juniper-private data link type, as per request from
    409  * Hannes Gredler <hannes (at) juniper.net>.
    410  * The DLT_ is used for internal communication with a
    411  * voice Adapter Card (PIC)
    412  */
    413 #define LINKTYPE_JUNIPER_VP     183
    414 
    415 /*
    416  * Arinc 429 frames.
    417  * DLT_ requested by Gianluca Varenni <gianluca.varenni (at) cacetech.com>.
    418  * Every frame contains a 32bit A429 label.
    419  * More documentation on Arinc 429 can be found at
    420  * http://www.condoreng.com/support/downloads/tutorials/ARINCTutorial.pdf
    421  */
    422 #define LINKTYPE_A429           184
    423 
    424 /*
    425  * Arinc 653 Interpartition Communication messages.
    426  * DLT_ requested by Gianluca Varenni <gianluca.varenni (at) cacetech.com>.
    427  * Please refer to the A653-1 standard for more information.
    428  */
    429 #define LINKTYPE_A653_ICM       185
    430 
    431 /*
    432  * This used to be "USB packets, beginning with a USB setup header;
    433  * requested by Paolo Abeni <paolo.abeni (at) email.it>."
    434  *
    435  * However, that header didn't work all that well - it left out some
    436  * useful information - and was abandoned in favor of the DLT_USB_LINUX
    437  * header.
    438  *
    439  * This is now used by FreeBSD for its BPF taps for USB; that has its
    440  * own headers.  So it is written, so it is done.
    441  */
    442 #define LINKTYPE_USB_FREEBSD	186
    443 
    444 /*
    445  * Bluetooth HCI UART transport layer (part H:4); requested by
    446  * Paolo Abeni.
    447  */
    448 #define LINKTYPE_BLUETOOTH_HCI_H4	187
    449 
    450 /*
    451  * IEEE 802.16 MAC Common Part Sublayer; requested by Maria Cruz
    452  * <cruz_petagay (at) bah.com>.
    453  */
    454 #define LINKTYPE_IEEE802_16_MAC_CPS	188
    455 
    456 /*
    457  * USB packets, beginning with a Linux USB header; requested by
    458  * Paolo Abeni <paolo.abeni (at) email.it>.
    459  */
    460 #define LINKTYPE_USB_LINUX		189
    461 
    462 /*
    463  * Controller Area Network (CAN) v. 2.0B packets.
    464  * DLT_ requested by Gianluca Varenni <gianluca.varenni (at) cacetech.com>.
    465  * Used to dump CAN packets coming from a CAN Vector board.
    466  * More documentation on the CAN v2.0B frames can be found at
    467  * http://www.can-cia.org/downloads/?269
    468  */
    469 #define LINKTYPE_CAN20B         190
    470 
    471 /*
    472  * IEEE 802.15.4, with address fields padded, as is done by Linux
    473  * drivers; requested by Juergen Schimmer.
    474  */
    475 #define LINKTYPE_IEEE802_15_4_LINUX	191
    476 
    477 /*
    478  * Per Packet Information encapsulated packets.
    479  * LINKTYPE_ requested by Gianluca Varenni <gianluca.varenni (at) cacetech.com>.
    480  */
    481 #define LINKTYPE_PPI			192
    482 
    483 /*
    484  * Header for 802.16 MAC Common Part Sublayer plus a radiotap radio header;
    485  * requested by Charles Clancy.
    486  */
    487 #define LINKTYPE_IEEE802_16_MAC_CPS_RADIO	193
    488 
    489 /*
    490  * Juniper-private data link type, as per request from
    491  * Hannes Gredler <hannes (at) juniper.net>.
    492  * The DLT_ is used for internal communication with a
    493  * integrated service module (ISM).
    494  */
    495 #define LINKTYPE_JUNIPER_ISM    194
    496 
    497 /*
    498  * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
    499  * nothing); requested by Mikko Saarnivala <mikko.saarnivala (at) sensinode.com>.
    500  */
    501 #define LINKTYPE_IEEE802_15_4	195
    502 
    503 /*
    504  * Various link-layer types, with a pseudo-header, for SITA
    505  * (http://www.sita.aero/); requested by Fulko Hew (fulko.hew (at) gmail.com).
    506  */
    507 #define LINKTYPE_SITA		196
    508 
    509 /*
    510  * Various link-layer types, with a pseudo-header, for Endace DAG cards;
    511  * encapsulates Endace ERF records.  Requested by Stephen Donnelly
    512  * <stephen (at) endace.com>.
    513  */
    514 #define LINKTYPE_ERF		197
    515 
    516 /*
    517  * Special header prepended to Ethernet packets when capturing from a
    518  * u10 Networks board.  Requested by Phil Mulholland
    519  * <phil (at) u10networks.com>.
    520  */
    521 #define LINKTYPE_RAIF1		198
    522 
    523 /*
    524  * IPMB packet for IPMI, beginning with the I2C slave address, followed
    525  * by the netFn and LUN, etc..  Requested by Chanthy Toeung
    526  * <chanthy.toeung (at) ca.kontron.com>.
    527  */
    528 #define LINKTYPE_IPMB		199
    529 
    530 /*
    531  * Juniper-private data link type, as per request from
    532  * Hannes Gredler <hannes (at) juniper.net>.
    533  * The DLT_ is used for capturing data on a secure tunnel interface.
    534  */
    535 #define LINKTYPE_JUNIPER_ST     200
    536 
    537 /*
    538  * Bluetooth HCI UART transport layer (part H:4), with pseudo-header
    539  * that includes direction information; requested by Paolo Abeni.
    540  */
    541 #define LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR	201
    542 
    543 /*
    544  * AX.25 packet with a 1-byte KISS header; see
    545  *
    546  *	http://www.ax25.net/kiss.htm
    547  *
    548  * as per Richard Stearn <richard (at) rns-stearn.demon.co.uk>.
    549  */
    550 #define LINKTYPE_AX25_KISS	202
    551 
    552 /*
    553  * LAPD packets from an ISDN channel, starting with the address field,
    554  * with no pseudo-header.
    555  * Requested by Varuna De Silva <varunax (at) gmail.com>.
    556  */
    557 #define LINKTYPE_LAPD		203
    558 
    559 /*
    560  * Variants of various link-layer headers, with a one-byte direction
    561  * pseudo-header prepended - zero means "received by this host",
    562  * non-zero (any non-zero value) means "sent by this host" - as per
    563  * Will Barker <w.barker (at) zen.co.uk>.
    564  */
    565 #define LINKTYPE_PPP_WITH_DIR	204	/* PPP */
    566 #define LINKTYPE_C_HDLC_WITH_DIR 205	/* Cisco HDLC */
    567 #define LINKTYPE_FRELAY_WITH_DIR 206	/* Frame Relay */
    568 #define LINKTYPE_LAPB_WITH_DIR	207	/* LAPB */
    569 
    570 /*
    571  * 208 is reserved for an as-yet-unspecified proprietary link-layer
    572  * type, as requested by Will Barker.
    573  */
    574 
    575 /*
    576  * IPMB with a Linux-specific pseudo-header; as requested by Alexey Neyman
    577  * <avn (at) pigeonpoint.com>.
    578  */
    579 #define LINKTYPE_IPMB_LINUX	209
    580 
    581 /*
    582  * FlexRay automotive bus - http://www.flexray.com/ - as requested
    583  * by Hannes Kaelber <hannes.kaelber (at) x2e.de>.
    584  */
    585 #define LINKTYPE_FLEXRAY	210
    586 
    587 /*
    588  * Media Oriented Systems Transport (MOST) bus for multimedia
    589  * transport - http://www.mostcooperation.com/ - as requested
    590  * by Hannes Kaelber <hannes.kaelber (at) x2e.de>.
    591  */
    592 #define LINKTYPE_MOST		211
    593 
    594 /*
    595  * Local Interconnect Network (LIN) bus for vehicle networks -
    596  * http://www.lin-subbus.org/ - as requested by Hannes Kaelber
    597  * <hannes.kaelber (at) x2e.de>.
    598  */
    599 #define LINKTYPE_LIN		212
    600 
    601 /*
    602  * X2E-private data link type used for serial line capture,
    603  * as requested by Hannes Kaelber <hannes.kaelber (at) x2e.de>.
    604  */
    605 #define LINKTYPE_X2E_SERIAL	213
    606 
    607 /*
    608  * X2E-private data link type used for the Xoraya data logger
    609  * family, as requested by Hannes Kaelber <hannes.kaelber (at) x2e.de>.
    610  */
    611 #define LINKTYPE_X2E_XORAYA	214
    612 
    613 /*
    614  * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
    615  * nothing), but with the PHY-level data for non-ASK PHYs (4 octets
    616  * of 0 as preamble, one octet of SFD, one octet of frame length+
    617  * reserved bit, and then the MAC-layer data, starting with the
    618  * frame control field).
    619  *
    620  * Requested by Max Filippov <jcmvbkbc (at) gmail.com>.
    621  */
    622 #define LINKTYPE_IEEE802_15_4_NONASK_PHY	215
    623 
    624 /*
    625  * David Gibson <david (at) gibson.dropbear.id.au> requested this for
    626  * captures from the Linux kernel /dev/input/eventN devices. This
    627  * is used to communicate keystrokes and mouse movements from the
    628  * Linux kernel to display systems, such as Xorg.
    629  */
    630 #define LINKTYPE_LINUX_EVDEV	216
    631 
    632 /*
    633  * GSM Um and Abis interfaces, preceded by a "gsmtap" header.
    634  *
    635  * Requested by Harald Welte <laforge (at) gnumonks.org>.
    636  */
    637 #define LINKTYPE_GSMTAP_UM	217
    638 #define LINKTYPE_GSMTAP_ABIS	218
    639 
    640 /*
    641  * MPLS, with an MPLS label as the link-layer header.
    642  * Requested by Michele Marchetto <michele (at) openbsd.org> on behalf
    643  * of OpenBSD.
    644  */
    645 #define LINKTYPE_MPLS		219
    646 
    647 /*
    648  * USB packets, beginning with a Linux USB header, with the USB header
    649  * padded to 64 bytes; required for memory-mapped access.
    650  */
    651 #define LINKTYPE_USB_LINUX_MMAPPED		220
    652 
    653 /*
    654  * DECT packets, with a pseudo-header; requested by
    655  * Matthias Wenzel <tcpdump (at) mazzoo.de>.
    656  */
    657 #define LINKTYPE_DECT		221
    658 
    659 /*
    660  * From: "Lidwa, Eric (GSFC-582.0)[SGT INC]" <eric.lidwa-1 (at) nasa.gov>
    661  * Date: Mon, 11 May 2009 11:18:30 -0500
    662  *
    663  * DLT_AOS. We need it for AOS Space Data Link Protocol.
    664  *   I have already written dissectors for but need an OK from
    665  *   legal before I can submit a patch.
    666  *
    667  */
    668 #define LINKTYPE_AOS		222
    669 
    670 /*
    671  * Wireless HART (Highway Addressable Remote Transducer)
    672  * From the HART Communication Foundation
    673  * IES/PAS 62591
    674  *
    675  * Requested by Sam Roberts <vieuxtech (at) gmail.com>.
    676  */
    677 #define LINKTYPE_WIHART		223
    678 
    679 /*
    680  * Fibre Channel FC-2 frames, beginning with a Frame_Header.
    681  * Requested by Kahou Lei <kahou82 (at) gmail.com>.
    682  */
    683 #define LINKTYPE_FC_2		224
    684 
    685 /*
    686  * Fibre Channel FC-2 frames, beginning with an encoding of the
    687  * SOF, and ending with an encoding of the EOF.
    688  *
    689  * The encodings represent the frame delimiters as 4-byte sequences
    690  * representing the corresponding ordered sets, with K28.5
    691  * represented as 0xBC, and the D symbols as the corresponding
    692  * byte values; for example, SOFi2, which is K28.5 - D21.5 - D1.2 - D21.2,
    693  * is represented as 0xBC 0xB5 0x55 0x55.
    694  *
    695  * Requested by Kahou Lei <kahou82 (at) gmail.com>.
    696  */
    697 #define LINKTYPE_FC_2_WITH_FRAME_DELIMS		225
    698 
    699 /*
    700  * Solaris ipnet pseudo-header; requested by Darren Reed <Darren.Reed (at) Sun.COM>.
    701  *
    702  * The pseudo-header starts with a one-byte version number; for version 2,
    703  * the pseudo-header is:
    704  *
    705  * struct dl_ipnetinfo {
    706  *     u_int8_t   dli_version;
    707  *     u_int8_t   dli_family;
    708  *     u_int16_t  dli_htype;
    709  *     u_int32_t  dli_pktlen;
    710  *     u_int32_t  dli_ifindex;
    711  *     u_int32_t  dli_grifindex;
    712  *     u_int32_t  dli_zsrc;
    713  *     u_int32_t  dli_zdst;
    714  * };
    715  *
    716  * dli_version is 2 for the current version of the pseudo-header.
    717  *
    718  * dli_family is a Solaris address family value, so it's 2 for IPv4
    719  * and 26 for IPv6.
    720  *
    721  * dli_htype is a "hook type" - 0 for incoming packets, 1 for outgoing
    722  * packets, and 2 for packets arriving from another zone on the same
    723  * machine.
    724  *
    725  * dli_pktlen is the length of the packet data following the pseudo-header
    726  * (so the captured length minus dli_pktlen is the length of the
    727  * pseudo-header, assuming the entire pseudo-header was captured).
    728  *
    729  * dli_ifindex is the interface index of the interface on which the
    730  * packet arrived.
    731  *
    732  * dli_grifindex is the group interface index number (for IPMP interfaces).
    733  *
    734  * dli_zsrc is the zone identifier for the source of the packet.
    735  *
    736  * dli_zdst is the zone identifier for the destination of the packet.
    737  *
    738  * A zone number of 0 is the global zone; a zone number of 0xffffffff
    739  * means that the packet arrived from another host on the network, not
    740  * from another zone on the same machine.
    741  *
    742  * An IPv4 or IPv6 datagram follows the pseudo-header; dli_family indicates
    743  * which of those it is.
    744  */
    745 #define LINKTYPE_IPNET		226
    746 
    747 /*
    748  * CAN (Controller Area Network) frames, with a pseudo-header as supplied
    749  * by Linux SocketCAN, and with multi-byte numerical fields in that header
    750  * in big-endian byte order.
    751  *
    752  * See Documentation/networking/can.txt in the Linux source.
    753  *
    754  * Requested by Felix Obenhuber <felix (at) obenhuber.de>.
    755  */
    756 #define LINKTYPE_CAN_SOCKETCAN	227
    757 
    758 /*
    759  * Raw IPv4/IPv6; different from DLT_RAW in that the DLT_ value specifies
    760  * whether it's v4 or v6.  Requested by Darren Reed <Darren.Reed (at) Sun.COM>.
    761  */
    762 #define LINKTYPE_IPV4		228
    763 #define LINKTYPE_IPV6		229
    764 
    765 /*
    766  * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
    767  * nothing), and with no FCS at the end of the frame; requested by
    768  * Jon Smirl <jonsmirl (at) gmail.com>.
    769  */
    770 #define LINKTYPE_IEEE802_15_4_NOFCS		230
    771 
    772 /*
    773  * Raw D-Bus:
    774  *
    775  *	http://www.freedesktop.org/wiki/Software/dbus
    776  *
    777  * messages:
    778  *
    779  *	http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages
    780  *
    781  * starting with the endianness flag, followed by the message type, etc.,
    782  * but without the authentication handshake before the message sequence:
    783  *
    784  *	http://dbus.freedesktop.org/doc/dbus-specification.html#auth-protocol
    785  *
    786  * Requested by Martin Vidner <martin (at) vidner.net>.
    787  */
    788 #define LINKTYPE_DBUS		231
    789 
    790 /*
    791  * Juniper-private data link type, as per request from
    792  * Hannes Gredler <hannes (at) juniper.net>.
    793  */
    794 #define LINKTYPE_JUNIPER_VS			232
    795 #define LINKTYPE_JUNIPER_SRX_E2E		233
    796 #define LINKTYPE_JUNIPER_FIBRECHANNEL		234
    797 
    798 /*
    799  * DVB-CI (DVB Common Interface for communication between a PC Card
    800  * module and a DVB receiver).  See
    801  *
    802  *	http://www.kaiser.cx/pcap-dvbci.html
    803  *
    804  * for the specification.
    805  *
    806  * Requested by Martin Kaiser <martin (at) kaiser.cx>.
    807  */
    808 #define LINKTYPE_DVB_CI		235
    809 
    810 /*
    811  * Variant of 3GPP TS 27.010 multiplexing protocol.  Requested
    812  * by Hans-Christoph Schemmel <hans-christoph.schemmel (at) cinterion.com>.
    813  */
    814 #define LINKTYPE_MUX27010	236
    815 
    816 /*
    817  * STANAG 5066 D_PDUs.  Requested by M. Baris Demiray
    818  * <barisdemiray (at) gmail.com>.
    819  */
    820 #define LINKTYPE_STANAG_5066_D_PDU		237
    821 
    822 /*
    823  * Juniper-private data link type, as per request from
    824  * Hannes Gredler <hannes (at) juniper.net>.
    825  */
    826 #define LINKTYPE_JUNIPER_ATM_CEMIC		238
    827 
    828 /*
    829  * NetFilter LOG messages
    830  * (payload of netlink NFNL_SUBSYS_ULOG/NFULNL_MSG_PACKET packets)
    831  *
    832  * Requested by Jakub Zawadzki <darkjames-ws (at) darkjames.pl>
    833  */
    834 #define LINKTYPE_NFLOG		239
    835 
    836 /*
    837  * Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
    838  * for Ethernet packets with a 4-byte pseudo-header and always
    839  * with the payload including the FCS, as supplied by their
    840  * netANALYZER hardware and software.
    841  *
    842  * Requested by Holger P. Frommer <HPfrommer (at) hilscher.com>
    843  */
    844 #define LINKTYPE_NETANALYZER	240
    845 
    846 /*
    847  * Hilscher Gesellschaft fuer Systemautomation mbH link-layer type
    848  * for Ethernet packets with a 4-byte pseudo-header and FCS and
    849  * 1 byte of SFD, as supplied by their netANALYZER hardware and
    850  * software.
    851  *
    852  * Requested by Holger P. Frommer <HPfrommer (at) hilscher.com>
    853  */
    854 #define LINKTYPE_NETANALYZER_TRANSPARENT	241
    855 
    856 /*
    857  * IP-over-InfiniBand, as specified by RFC 4391.
    858  *
    859  * Requested by Petr Sumbera <petr.sumbera (at) oracle.com>.
    860  */
    861 #define LINKTYPE_IPOIB		242
    862 
    863 /*
    864  * MPEG-2 transport stream (ISO 13818-1/ITU-T H.222.0).
    865  *
    866  * Requested by Guy Martin <gmsoft (at) tuxicoman.be>.
    867  */
    868 #define LINKTYPE_MPEG_2_TS	243
    869 
    870 /*
    871  * ng4T GmbH's UMTS Iub/Iur-over-ATM and Iub/Iur-over-IP format as
    872  * used by their ng40 protocol tester.
    873  *
    874  * Requested by Jens Grimmer <jens.grimmer (at) ng4t.com>.
    875  */
    876 #define LINKTYPE_NG40		244
    877 
    878 /*
    879  * Pseudo-header giving adapter number and flags, followed by an NFC
    880  * (Near-Field Communications) Logical Link Control Protocol (LLCP) PDU,
    881  * as specified by NFC Forum Logical Link Control Protocol Technical
    882  * Specification LLCP 1.1.
    883  *
    884  * Requested by Mike Wakerly <mikey (at) google.com>.
    885  */
    886 #define LINKTYPE_NFC_LLCP	245
    887 
    888 /*
    889  * pfsync output; DLT_PFSYNC is 18, which collides with DLT_CIP in
    890  * SuSE 6.3, on OpenBSD, NetBSD, DragonFly BSD, and Mac OS X, and
    891  * is 121, which collides with DLT_HHDLC, in FreeBSD.  We pick a
    892  * shiny new link-layer header type value that doesn't collide with
    893  * anything, in the hopes that future pfsync savefiles, if any,
    894  * won't require special hacks to distinguish from other savefiles.
    895  *
    896  */
    897 #define LINKTYPE_PFSYNC		246
    898 
    899 /*
    900  * Raw InfiniBand packets, starting with the Local Routing Header.
    901  *
    902  * Requested by Oren Kladnitsky <orenk (at) mellanox.com>.
    903  */
    904 #define LINKTYPE_INFINIBAND	247
    905 
    906 /*
    907  * SCTP, with no lower-level protocols (i.e., no IPv4 or IPv6).
    908  *
    909  * Requested by Michael Tuexen <Michael.Tuexen (at) lurchi.franken.de>.
    910  */
    911 #define LINKTYPE_SCTP		248
    912 
    913 /*
    914  * USB packets, beginning with a USBPcap header.
    915  *
    916  * Requested by Tomasz Mon <desowin (at) gmail.com>
    917  */
    918 #define LINKTYPE_USBPCAP	249
    919 
    920 /*
    921  * Schweitzer Engineering Laboratories "RTAC" product serial-line
    922  * packets.
    923  *
    924  * Requested by Chris Bontje <chris_bontje (at) selinc.com>.
    925  */
    926 #define DLT_RTAC_SERIAL		250
    927 
    928 /*
    929  * Bluetooth Low Energy air interface link-layer packets.
    930  *
    931  * Requested by Mike Kershaw <dragorn (at) kismetwireless.net>.
    932  */
    933 #define LINKTYPE_BLUETOOTH_LE_LL	251
    934 
    935 /*
    936  * Link-layer header type for upper-protocol layer PDU saves from wireshark.
    937  *
    938  * the actual contents are determined by two TAGs stored with each
    939  * packet:
    940  *   EXP_PDU_TAG_LINKTYPE          the link type (LINKTYPE_ value) of the
    941  *				   original packet.
    942  *
    943  *   EXP_PDU_TAG_PROTO_NAME        the name of the wireshark dissector
    944  * 				   that can make sense of the data stored.
    945  */
    946 #define LINKTYPE_WIRESHARK_UPPER_PDU	252
    947 
    948 /*
    949  * Link-layer header type for the netlink protocol (nlmon devices).
    950  */
    951 #define LINKTYPE_NETLINK		253
    952 
    953 /*
    954  * Bluetooth Linux Monitor headers for the BlueZ stack.
    955  */
    956 #define LINKTYPE_BLUETOOTH_LINUX_MONITOR	254
    957 
    958 /*
    959  * Bluetooth Basic Rate/Enhanced Data Rate baseband packets, as
    960  * captured by Ubertooth.
    961  */
    962 #define LINKTYPE_BLUETOOTH_BREDR_BB	255
    963 
    964 /*
    965  * Bluetooth Low Energy link layer packets, as captured by Ubertooth.
    966  */
    967 #define LINKTYPE_BLUETOOTH_LE_LL_WITH_PHDR	256
    968 
    969 /*
    970  * PROFIBUS data link layer.
    971  */
    972 #define LINKTYPE_PROFIBUS_DL		257
    973 
    974 /*
    975  * Apple's DLT_PKTAP headers.
    976  *
    977  * Sadly, the folks at Apple either had no clue that the DLT_USERn values
    978  * are for internal use within an organization and partners only, and
    979  * didn't know that the right way to get a link-layer header type is to
    980  * ask tcpdump.org for one, or knew and didn't care, so they just
    981  * used DLT_USER2, which causes problems for everything except for
    982  * their version of tcpdump.
    983  *
    984  * So I'll just give them one; hopefully this will show up in a
    985  * libpcap release in time for them to get this into 10.10 Big Sur
    986  * or whatever Mavericks' successor is called.  LINKTYPE_PKTAP
    987  * will be 258 *even on OS X*; that is *intentional*, so that
    988  * PKTAP files look the same on *all* OSes (different OSes can have
    989  * different numerical values for a given DLT_, but *MUST NOT* have
    990  * different values for what goes in a file, as files can be moved
    991  * between OSes!).
    992  */
    993 #define LINKTYPE_PKTAP		258
    994 
    995 /*
    996  * Ethernet packets preceded by a header giving the last 6 octets
    997  * of the preamble specified by 802.3-2012 Clause 65, section
    998  * 65.1.3.2 "Transmit".
    999  */
   1000 #define LINKTYPE_EPON		259
   1001 
   1002 /*
   1003  * IPMI trace packets, as specified by Table 3-20 "Trace Data Block Format"
   1004  * in the PICMG HPM.2 specification.
   1005  */
   1006 #define LINKTYPE_IPMI_HPM_2	260
   1007 
   1008 /*
   1009  * per  Joshua Wright <jwright (at) hasborg.com>, formats for Zwave captures.
   1010  */
   1011 #define LINKTYPE_ZWAVE_R1_R2	261
   1012 #define LINKTYPE_ZWAVE_R3	262
   1013 
   1014 /*
   1015  * per Steve Karg <skarg (at) users.sourceforge.net>, formats for Wattstopper
   1016  * Digital Lighting Management room bus serial protocol captures.
   1017  */
   1018 #define LINKTYPE_WATTSTOPPER_DLM 263
   1019 
   1020 /*
   1021  * ISO 14443 contactless smart card messages.
   1022  */
   1023 #define LINKTYPE_ISO_14443      264
   1024 
   1025 /*
   1026  * Radio data system (RDS) groups.  IEC 62106.
   1027  * Per Jonathan Brucker <jonathan.brucke (at) gmail.com>.
   1028  */
   1029 #define LINKTYPE_RDS		265
   1030 
   1031 #define LINKTYPE_MATCHING_MAX	265		/* highest value in the "matching" range */
   1032 
   1033 static struct linktype_map {
   1034 	int	dlt;
   1035 	int	linktype;
   1036 } map[] = {
   1037 	/*
   1038 	 * These DLT_* codes have LINKTYPE_* codes with values identical
   1039 	 * to the values of the corresponding DLT_* code.
   1040 	 */
   1041 	{ DLT_NULL,		LINKTYPE_NULL },
   1042 	{ DLT_EN10MB,		LINKTYPE_ETHERNET },
   1043 	{ DLT_EN3MB,		LINKTYPE_EXP_ETHERNET },
   1044 	{ DLT_AX25,		LINKTYPE_AX25 },
   1045 	{ DLT_PRONET,		LINKTYPE_PRONET },
   1046 	{ DLT_CHAOS,		LINKTYPE_CHAOS },
   1047 	{ DLT_IEEE802,		LINKTYPE_IEEE802_5 },
   1048 	{ DLT_ARCNET,		LINKTYPE_ARCNET_BSD },
   1049 	{ DLT_SLIP,		LINKTYPE_SLIP },
   1050 	{ DLT_PPP,		LINKTYPE_PPP },
   1051 	{ DLT_FDDI,	 	LINKTYPE_FDDI },
   1052 	{ DLT_SYMANTEC_FIREWALL, LINKTYPE_SYMANTEC_FIREWALL },
   1053 
   1054 	/*
   1055 	 * These DLT_* codes have different values on different
   1056 	 * platforms; we map them to LINKTYPE_* codes that
   1057 	 * have values that should never be equal to any DLT_*
   1058 	 * code.
   1059 	 */
   1060 #ifdef DLT_FR
   1061 	/* BSD/OS Frame Relay */
   1062 	{ DLT_FR,		LINKTYPE_FRELAY },
   1063 #endif
   1064 
   1065 	{ DLT_ATM_RFC1483, 	LINKTYPE_ATM_RFC1483 },
   1066 	{ DLT_RAW,		LINKTYPE_RAW },
   1067 	{ DLT_SLIP_BSDOS,	LINKTYPE_SLIP_BSDOS },
   1068 	{ DLT_PPP_BSDOS,	LINKTYPE_PPP_BSDOS },
   1069 
   1070 	/* BSD/OS Cisco HDLC */
   1071 	{ DLT_C_HDLC,		LINKTYPE_C_HDLC },
   1072 
   1073 	/*
   1074 	 * These DLT_* codes are not on all platforms, but, so far,
   1075 	 * there don't appear to be any platforms that define
   1076 	 * other codes with those values; we map them to
   1077 	 * different LINKTYPE_* values anyway, just in case.
   1078 	 */
   1079 
   1080 	/* Linux ATM Classical IP */
   1081 	{ DLT_ATM_CLIP,		LINKTYPE_ATM_CLIP },
   1082 
   1083 	/* NetBSD sync/async serial PPP (or Cisco HDLC) */
   1084 	{ DLT_PPP_SERIAL,	LINKTYPE_PPP_HDLC },
   1085 
   1086 	/* NetBSD PPP over Ethernet */
   1087 	{ DLT_PPP_ETHER,	LINKTYPE_PPP_ETHER },
   1088 
   1089 	/*
   1090 	 * All LINKTYPE_ values between LINKTYPE_MATCHING_MIN
   1091 	 * and LINKTYPE_MATCHING_MAX are mapped to identical
   1092 	 * DLT_ values.
   1093 	 */
   1094 
   1095 	{ -1,			-1 }
   1096 };
   1097 
   1098 int
   1099 dlt_to_linktype(int dlt)
   1100 {
   1101 	int i;
   1102 
   1103 	/*
   1104 	 * DLTs that, on some platforms, have values in the matching range
   1105 	 * but that *don't* have the same value as the corresponding
   1106 	 * LINKTYPE because, for some reason, not all OSes have the
   1107 	 * same value for that DLT (note that the DLT's value might be
   1108 	 * outside the matching range on some of those OSes).
   1109 	 */
   1110 	if (dlt == DLT_PFSYNC)
   1111 		return (LINKTYPE_PFSYNC);
   1112 	if (dlt == DLT_PKTAP)
   1113 		return (LINKTYPE_PKTAP);
   1114 
   1115 	/*
   1116 	 * For all other values in the matching range, the DLT
   1117 	 * value is the same as the LINKTYPE value.
   1118 	 */
   1119 	if (dlt >= DLT_MATCHING_MIN && dlt <= DLT_MATCHING_MAX)
   1120 		return (dlt);
   1121 
   1122 	/*
   1123 	 * Map the values outside that range.
   1124 	 */
   1125 	for (i = 0; map[i].dlt != -1; i++) {
   1126 		if (map[i].dlt == dlt)
   1127 			return (map[i].linktype);
   1128 	}
   1129 
   1130 	/*
   1131 	 * If we don't have a mapping for this DLT, return an
   1132 	 * error; that means that this is a value with no corresponding
   1133 	 * LINKTYPE, and we need to assign one.
   1134 	 */
   1135 	return (-1);
   1136 }
   1137 
   1138 int
   1139 linktype_to_dlt(int linktype)
   1140 {
   1141 	int i;
   1142 
   1143 	/*
   1144 	 * LINKTYPEs in the matching range that *don't*
   1145 	 * have the same value as the corresponding DLTs
   1146 	 * because, for some reason, not all OSes have the
   1147 	 * same value for that DLT.
   1148 	 */
   1149 	if (linktype == LINKTYPE_PFSYNC)
   1150 		return (DLT_PFSYNC);
   1151 	if (linktype == LINKTYPE_PKTAP)
   1152 		return (DLT_PKTAP);
   1153 
   1154 	/*
   1155 	 * For all other values in the matching range, the LINKTYPE
   1156 	 * value is the same as the DLT value.
   1157 	 */
   1158 	if (linktype >= LINKTYPE_MATCHING_MIN &&
   1159 	    linktype <= LINKTYPE_MATCHING_MAX)
   1160 		return (linktype);
   1161 
   1162 	/*
   1163 	 * Map the values outside that range.
   1164 	 */
   1165 	for (i = 0; map[i].linktype != -1; i++) {
   1166 		if (map[i].linktype == linktype)
   1167 			return (map[i].dlt);
   1168 	}
   1169 
   1170 	/*
   1171 	 * If we don't have an entry for this LINKTYPE, return
   1172 	 * the link type value; it may be a DLT from an older
   1173 	 * version of libpcap.
   1174 	 */
   1175 	return linktype;
   1176 }
   1177 
   1178 #define EXTRACT_
   1179 
   1180 /*
   1181  * DLT_LINUX_SLL packets with a protocol type of LINUX_SLL_P_CAN or
   1182  * LINUX_SLL_P_CANFD have SocketCAN headers in front of the payload,
   1183  * with the CAN ID being in host byte order.
   1184  *
   1185  * When reading a DLT_LINUX_SLL capture file, we need to check for those
   1186  * packets and convert the CAN ID from the byte order of the host that
   1187  * wrote the file to this host's byte order.
   1188  */
   1189 static void
   1190 swap_linux_sll_header(const struct pcap_pkthdr *hdr, u_char *buf)
   1191 {
   1192 	u_int caplen = hdr->caplen;
   1193 	u_int length = hdr->len;
   1194 	struct sll_header *shdr = (struct sll_header *)buf;
   1195 	u_int16_t protocol;
   1196 	pcap_can_socketcan_hdr *chdr;
   1197 
   1198 	if (caplen < (u_int) sizeof(struct sll_header) ||
   1199 	    length < (u_int) sizeof(struct sll_header)) {
   1200 		/* Not enough data to have the protocol field */
   1201 		return;
   1202 	}
   1203 
   1204 	protocol = EXTRACT_16BITS(&shdr->sll_protocol);
   1205 	if (protocol != LINUX_SLL_P_CAN && protocol != LINUX_SLL_P_CANFD)
   1206 		return;
   1207 
   1208 	/*
   1209 	 * SocketCAN packet; fix up the packet's header.
   1210 	 */
   1211 	chdr = (pcap_can_socketcan_hdr *)(buf + sizeof(struct sll_header));
   1212 	if (caplen < (u_int) sizeof(struct sll_header) + sizeof(chdr->can_id) ||
   1213 	    length < (u_int) sizeof(struct sll_header) + sizeof(chdr->can_id)) {
   1214 		/* Not enough data to have the CAN ID */
   1215 		return;
   1216 	}
   1217 	chdr->can_id = SWAPLONG(chdr->can_id);
   1218 }
   1219 
   1220 /*
   1221  * The DLT_USB_LINUX and DLT_USB_LINUX_MMAPPED headers are in host
   1222  * byte order when capturing (it's supplied directly from a
   1223  * memory-mapped buffer shared by the kernel).
   1224  *
   1225  * When reading a DLT_USB_LINUX or DLT_USB_LINUX_MMAPPED capture file,
   1226  * we need to convert it from the byte order of the host that wrote
   1227  * the file to this host's byte order.
   1228  */
   1229 static void
   1230 swap_linux_usb_header(const struct pcap_pkthdr *hdr, u_char *buf,
   1231     int header_len_64_bytes)
   1232 {
   1233 	pcap_usb_header_mmapped *uhdr = (pcap_usb_header_mmapped *)buf;
   1234 	bpf_u_int32 offset = 0;
   1235 
   1236 	/*
   1237 	 * "offset" is the offset *past* the field we're swapping;
   1238 	 * we skip the field *before* checking to make sure
   1239 	 * the captured data length includes the entire field.
   1240 	 */
   1241 
   1242 	/*
   1243 	 * The URB id is a totally opaque value; do we really need to
   1244 	 * convert it to the reading host's byte order???
   1245 	 */
   1246 	offset += 8;			/* skip past id */
   1247 	if (hdr->caplen < offset)
   1248 		return;
   1249 	uhdr->id = SWAPLL(uhdr->id);
   1250 
   1251 	offset += 4;			/* skip past various 1-byte fields */
   1252 
   1253 	offset += 2;			/* skip past bus_id */
   1254 	if (hdr->caplen < offset)
   1255 		return;
   1256 	uhdr->bus_id = SWAPSHORT(uhdr->bus_id);
   1257 
   1258 	offset += 2;			/* skip past various 1-byte fields */
   1259 
   1260 	offset += 8;			/* skip past ts_sec */
   1261 	if (hdr->caplen < offset)
   1262 		return;
   1263 	uhdr->ts_sec = SWAPLL(uhdr->ts_sec);
   1264 
   1265 	offset += 4;			/* skip past ts_usec */
   1266 	if (hdr->caplen < offset)
   1267 		return;
   1268 	uhdr->ts_usec = SWAPLONG(uhdr->ts_usec);
   1269 
   1270 	offset += 4;			/* skip past status */
   1271 	if (hdr->caplen < offset)
   1272 		return;
   1273 	uhdr->status = SWAPLONG(uhdr->status);
   1274 
   1275 	offset += 4;			/* skip past urb_len */
   1276 	if (hdr->caplen < offset)
   1277 		return;
   1278 	uhdr->urb_len = SWAPLONG(uhdr->urb_len);
   1279 
   1280 	offset += 4;			/* skip past data_len */
   1281 	if (hdr->caplen < offset)
   1282 		return;
   1283 	uhdr->data_len = SWAPLONG(uhdr->data_len);
   1284 
   1285 	if (uhdr->transfer_type == URB_ISOCHRONOUS) {
   1286 		offset += 4;			/* skip past s.iso.error_count */
   1287 		if (hdr->caplen < offset)
   1288 			return;
   1289 		uhdr->s.iso.error_count = SWAPLONG(uhdr->s.iso.error_count);
   1290 
   1291 		offset += 4;			/* skip past s.iso.numdesc */
   1292 		if (hdr->caplen < offset)
   1293 			return;
   1294 		uhdr->s.iso.numdesc = SWAPLONG(uhdr->s.iso.numdesc);
   1295 	} else
   1296 		offset += 8;			/* skip USB setup header */
   1297 
   1298 	/*
   1299 	 * With the old header, there are no isochronous descriptors
   1300 	 * after the header.
   1301 	 *
   1302 	 * With the new header, the actual number of descriptors in
   1303 	 * the header is not s.iso.numdesc, it's ndesc - only the
   1304 	 * first N descriptors, for some value of N, are put into
   1305 	 * the header, and ndesc is set to the actual number copied.
   1306 	 * In addition, if s.iso.numdesc is negative, no descriptors
   1307 	 * are captured, and ndesc is set to 0.
   1308 	 */
   1309 	if (header_len_64_bytes) {
   1310 		/*
   1311 		 * This is either the "version 1" header, with
   1312 		 * 16 bytes of additional fields at the end, or
   1313 		 * a "version 0" header from a memory-mapped
   1314 		 * capture, with 16 bytes of zeroed-out padding
   1315 		 * at the end.  Byte swap them as if this were
   1316 		 * a "version 1" header.
   1317 		 */
   1318 		offset += 4;			/* skip past interval */
   1319 		if (hdr->caplen < offset)
   1320 			return;
   1321 		uhdr->interval = SWAPLONG(uhdr->interval);
   1322 
   1323 		offset += 4;			/* skip past start_frame */
   1324 		if (hdr->caplen < offset)
   1325 			return;
   1326 		uhdr->start_frame = SWAPLONG(uhdr->start_frame);
   1327 
   1328 		offset += 4;			/* skip past xfer_flags */
   1329 		if (hdr->caplen < offset)
   1330 			return;
   1331 		uhdr->xfer_flags = SWAPLONG(uhdr->xfer_flags);
   1332 
   1333 		offset += 4;			/* skip past ndesc */
   1334 		if (hdr->caplen < offset)
   1335 			return;
   1336 		uhdr->ndesc = SWAPLONG(uhdr->ndesc);
   1337 
   1338 		if (uhdr->transfer_type == URB_ISOCHRONOUS) {
   1339 			/* swap the values in struct linux_usb_isodesc */
   1340 			usb_isodesc *pisodesc;
   1341 			u_int32_t i;
   1342 
   1343 			pisodesc = (usb_isodesc *)(void *)(buf+offset);
   1344 			for (i = 0; i < uhdr->ndesc; i++) {
   1345 				offset += 4;		/* skip past status */
   1346 				if (hdr->caplen < offset)
   1347 					return;
   1348 				pisodesc->status = SWAPLONG(pisodesc->status);
   1349 
   1350 				offset += 4;		/* skip past offset */
   1351 				if (hdr->caplen < offset)
   1352 					return;
   1353 				pisodesc->offset = SWAPLONG(pisodesc->offset);
   1354 
   1355 				offset += 4;		/* skip past len */
   1356 				if (hdr->caplen < offset)
   1357 					return;
   1358 				pisodesc->len = SWAPLONG(pisodesc->len);
   1359 
   1360 				offset += 4;		/* skip past padding */
   1361 
   1362 				pisodesc++;
   1363 			}
   1364 		}
   1365 	}
   1366 }
   1367 
   1368 /*
   1369  * The DLT_NFLOG "packets" have a mixture of big-endian and host-byte-order
   1370  * data.  They begin with a fixed-length header with big-endian fields,
   1371  * followed by a set of TLVs, where the type and length are in host
   1372  * byte order but the values are either big-endian or are a raw byte
   1373  * sequence that's the same regardless of the host's byte order.
   1374  *
   1375  * When reading a DLT_NFLOG capture file, we need to convert the type
   1376  * and length values from the byte order of the host that wrote the
   1377  * file to the byte order of this host.
   1378  */
   1379 static void
   1380 swap_nflog_header(const struct pcap_pkthdr *hdr, u_char *buf)
   1381 {
   1382 	u_char *p = buf;
   1383 	nflog_hdr_t *nfhdr = (nflog_hdr_t *)buf;
   1384 	nflog_tlv_t *tlv;
   1385 	u_int caplen = hdr->caplen;
   1386 	u_int length = hdr->len;
   1387 	u_int16_t size;
   1388 
   1389 	if (caplen < (u_int) sizeof(nflog_hdr_t) ||
   1390 	    length < (u_int) sizeof(nflog_hdr_t)) {
   1391 		/* Not enough data to have any TLVs. */
   1392 		return;
   1393 	}
   1394 
   1395 	if (nfhdr->nflog_version != 0) {
   1396 		/* Unknown NFLOG version */
   1397 		return;
   1398 	}
   1399 
   1400 	length -= sizeof(nflog_hdr_t);
   1401 	caplen -= sizeof(nflog_hdr_t);
   1402 	p += sizeof(nflog_hdr_t);
   1403 
   1404 	while (caplen >= sizeof(nflog_tlv_t)) {
   1405 		tlv = (nflog_tlv_t *) p;
   1406 
   1407 		/* Swap the type and length. */
   1408 		tlv->tlv_type = SWAPSHORT(tlv->tlv_type);
   1409 		tlv->tlv_length = SWAPSHORT(tlv->tlv_length);
   1410 
   1411 		/* Get the length of the TLV. */
   1412 		size = tlv->tlv_length;
   1413 		if (size % 4 != 0)
   1414 			size += 4 - size % 4;
   1415 
   1416 		/* Is the TLV's length less than the minimum? */
   1417 		if (size < sizeof(nflog_tlv_t)) {
   1418 			/* Yes. Give up now. */
   1419 			return;
   1420 		}
   1421 
   1422 		/* Do we have enough data for the full TLV? */
   1423 		if (caplen < size || length < size) {
   1424 			/* No. */
   1425 			return;
   1426 		}
   1427 
   1428 		/* Skip over the TLV. */
   1429 		length -= size;
   1430 		caplen -= size;
   1431 		p += size;
   1432 	}
   1433 }
   1434 
   1435 void
   1436 swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr, u_char *data)
   1437 {
   1438 	/*
   1439 	 * Convert pseudo-headers from the byte order of
   1440 	 * the host on which the file was saved to our
   1441 	 * byte order, as necessary.
   1442 	 */
   1443 	switch (linktype) {
   1444 
   1445 	case DLT_LINUX_SLL:
   1446 		swap_linux_sll_header(hdr, data);
   1447 		break;
   1448 
   1449 	case DLT_USB_LINUX:
   1450 		swap_linux_usb_header(hdr, data, 0);
   1451 		break;
   1452 
   1453 	case DLT_USB_LINUX_MMAPPED:
   1454 		swap_linux_usb_header(hdr, data, 1);
   1455 		break;
   1456 
   1457 	case DLT_NFLOG:
   1458 		swap_nflog_header(hdr, data);
   1459 		break;
   1460 	}
   1461 }
   1462