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      1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
      2 /*
      3  * Copyright (c) 1994, 1995, 1996, 1997, 1998
      4  *	The Regents of the University of California.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *	This product includes software developed by the Computer Systems
     17  *	Engineering Group at Lawrence Berkeley Laboratory.
     18  * 4. Neither the name of the University nor of the Laboratory may be used
     19  *    to endorse or promote products derived from this software without
     20  *    specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #ifdef HAVE_CONFIG_H
     36 #include "config.h"
     37 #endif
     38 
     39 #include <sys/types.h>
     40 #include <sys/socket.h>
     41 #include <netinet/in.h>
     42 
     43 #include <net/if.h>
     44 
     45 #include <ctype.h>
     46 #include <errno.h>
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include <ifaddrs.h>
     51 
     52 #include "pcap-int.h"
     53 
     54 #ifdef HAVE_OS_PROTO_H
     55 #include "os-proto.h"
     56 #endif
     57 
     58 /*
     59  * We don't do this on Solaris 11 and later, as it appears there aren't
     60  * any AF_PACKET addresses on interfaces, so we don't need this, and
     61  * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
     62  * and their definitions of some data structures collide.
     63  */
     64 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
     65 # ifdef HAVE_NETPACKET_PACKET_H
     66 /* Linux distributions with newer glibc */
     67 #  include <netpacket/packet.h>
     68 # else /* HAVE_NETPACKET_PACKET_H */
     69 /* LynxOS, Linux distributions with older glibc */
     70 # ifdef __Lynx__
     71 /* LynxOS */
     72 #  include <netpacket/if_packet.h>
     73 # else /* __Lynx__ */
     74 /* Linux */
     75 #  include <linux/types.h>
     76 #  include <linux/if_packet.h>
     77 # endif /* __Lynx__ */
     78 # endif /* HAVE_NETPACKET_PACKET_H */
     79 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
     80 
     81 /*
     82  * This is fun.
     83  *
     84  * In older BSD systems, socket addresses were fixed-length, and
     85  * "sizeof (struct sockaddr)" gave the size of the structure.
     86  * All addresses fit within a "struct sockaddr".
     87  *
     88  * In newer BSD systems, the socket address is variable-length, and
     89  * there's an "sa_len" field giving the length of the structure;
     90  * this allows socket addresses to be longer than 2 bytes of family
     91  * and 14 bytes of data.
     92  *
     93  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
     94  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
     95  * than "struct sockaddr"), and some use the new BSD scheme.
     96  *
     97  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
     98  * macro that determines the size based on the address family.  Other
     99  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
    100  * but not in the final version).  On the latter systems, we explicitly
    101  * check the AF_ type to determine the length; we assume that on
    102  * all those systems we have "struct sockaddr_storage".
    103  */
    104 #ifndef SA_LEN
    105 #ifdef HAVE_SOCKADDR_SA_LEN
    106 #define SA_LEN(addr)	((addr)->sa_len)
    107 #else /* HAVE_SOCKADDR_SA_LEN */
    108 #ifdef HAVE_SOCKADDR_STORAGE
    109 static size_t
    110 get_sa_len(struct sockaddr *addr)
    111 {
    112 	switch (addr->sa_family) {
    113 
    114 #ifdef AF_INET
    115 	case AF_INET:
    116 		return (sizeof (struct sockaddr_in));
    117 #endif
    118 
    119 #ifdef AF_INET6
    120 	case AF_INET6:
    121 		return (sizeof (struct sockaddr_in6));
    122 #endif
    123 
    124 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
    125 	case AF_PACKET:
    126 		return (sizeof (struct sockaddr_ll));
    127 #endif
    128 
    129 	default:
    130 		return (sizeof (struct sockaddr));
    131 	}
    132 }
    133 #define SA_LEN(addr)	(get_sa_len(addr))
    134 #else /* HAVE_SOCKADDR_STORAGE */
    135 #define SA_LEN(addr)	(sizeof (struct sockaddr))
    136 #endif /* HAVE_SOCKADDR_STORAGE */
    137 #endif /* HAVE_SOCKADDR_SA_LEN */
    138 #endif /* SA_LEN */
    139 
    140 /*
    141  * Get a list of all interfaces that are up and that we can open.
    142  * Returns -1 on error, 0 otherwise.
    143  * The list, as returned through "alldevsp", may be null if no interfaces
    144  * could be opened.
    145  */
    146 int
    147 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
    148 {
    149 	pcap_if_t *devlist = NULL;
    150 	struct ifaddrs *ifap, *ifa;
    151 	struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
    152 	size_t addr_size, broadaddr_size, dstaddr_size;
    153 	int ret = 0;
    154 	char *p, *q;
    155 
    156 	/*
    157 	 * Get the list of interface addresses.
    158 	 *
    159 	 * Note: this won't return information about interfaces
    160 	 * with no addresses, so, if a platform has interfaces
    161 	 * with no interfaces on which traffic can be captured,
    162 	 * we must check for those interfaces as well (see, for
    163 	 * example, what's done on Linux).
    164 	 *
    165 	 * LAN interfaces will probably have link-layer
    166 	 * addresses; I don't know whether all implementations
    167 	 * of "getifaddrs()" now, or in the future, will return
    168 	 * those.
    169 	 */
    170 	if (getifaddrs(&ifap) != 0) {
    171 		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
    172 		    "getifaddrs: %s", pcap_strerror(errno));
    173 		return (-1);
    174 	}
    175 	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
    176 		/*
    177 		 * "ifa_addr" was apparently null on at least one
    178 		 * interface on some system.  Therefore, we supply
    179 		 * the address and netmask only if "ifa_addr" is
    180 		 * non-null (if there's no address, there's obviously
    181 		 * no netmask).
    182 		 */
    183 		if (ifa->ifa_addr != NULL) {
    184 			addr = ifa->ifa_addr;
    185 			addr_size = SA_LEN(addr);
    186 			netmask = ifa->ifa_netmask;
    187 		} else {
    188 			addr = NULL;
    189 			addr_size = 0;
    190 			netmask = NULL;
    191 		}
    192 
    193 		/*
    194 		 * Note that, on some platforms, ifa_broadaddr and
    195 		 * ifa_dstaddr could be the same field (true on at
    196 		 * least some versions of *BSD and OS X), so we
    197 		 * can't just check whether the broadcast address
    198 		 * is null and add it if so and check whether the
    199 		 * destination address is null and add it if so.
    200 		 *
    201 		 * Therefore, we must also check the IFF_BROADCAST
    202 		 * flag, and only add a broadcast address if it's
    203 		 * set, and check the IFF_POINTTOPOINT flag, and
    204 		 * only add a destination address if it's set (as
    205 		 * per man page recommendations on some of those
    206 		 * platforms).
    207 		 */
    208 		if (ifa->ifa_flags & IFF_BROADCAST &&
    209 		    ifa->ifa_broadaddr != NULL) {
    210 			broadaddr = ifa->ifa_broadaddr;
    211 			broadaddr_size = SA_LEN(broadaddr);
    212 		} else {
    213 			broadaddr = NULL;
    214 			broadaddr_size = 0;
    215 		}
    216 		if (ifa->ifa_flags & IFF_POINTOPOINT &&
    217 		    ifa->ifa_dstaddr != NULL) {
    218 			dstaddr = ifa->ifa_dstaddr;
    219 			dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
    220 		} else {
    221 			dstaddr = NULL;
    222 			dstaddr_size = 0;
    223 		}
    224 
    225 		/*
    226 		 * If this entry has a colon followed by a number at
    227 		 * the end, we assume it's a logical interface.  Those
    228 		 * are just the way you assign multiple IP addresses to
    229 		 * a real interface on Linux, so an entry for a logical
    230 		 * interface should be treated like the entry for the
    231 		 * real interface; we do that by stripping off the ":"
    232 		 * and the number.
    233 		 *
    234 		 * XXX - should we do this only on Linux?
    235 		 */
    236 		p = strchr(ifa->ifa_name, ':');
    237 		if (p != NULL) {
    238 			/*
    239 			 * We have a ":"; is it followed by a number?
    240 			 */
    241 			q = p + 1;
    242 			while (isdigit((unsigned char)*q))
    243 				q++;
    244 			if (*q == '\0') {
    245 				/*
    246 				 * All digits after the ":" until the end.
    247 				 * Strip off the ":" and everything after
    248 				 * it.
    249 				 */
    250 			       *p = '\0';
    251 			}
    252 		}
    253 
    254 		/*
    255 		 * Add information for this address to the list.
    256 		 */
    257 		if (add_addr_to_iflist(&devlist, ifa->ifa_name,
    258 		    ifa->ifa_flags, addr, addr_size, netmask, addr_size,
    259 		    broadaddr, broadaddr_size, dstaddr, dstaddr_size,
    260 		    errbuf) < 0) {
    261 			ret = -1;
    262 			break;
    263 		}
    264 	}
    265 
    266 	freeifaddrs(ifap);
    267 
    268 	if (ret == -1) {
    269 		/*
    270 		 * We had an error; free the list we've been constructing.
    271 		 */
    272 		if (devlist != NULL) {
    273 			pcap_freealldevs(devlist);
    274 			devlist = NULL;
    275 		}
    276 	}
    277 
    278 	*alldevsp = devlist;
    279 	return (ret);
    280 }
    281