contrib/libpcap-0.9/fad-getad.c

   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 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.10.2.2 2007/09/14 00:45:17 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include <sys/types.h>
  45 #include <sys/socket.h>
  46 #include <netinet/in.h>
  47
  48 #include <net/if.h>
  49
  50 #include <ctype.h>
  51 #include <errno.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <ifaddrs.h>
  56
  57 #include "pcap-int.h"
  58
  59 #ifdef HAVE_OS_PROTO_H
  60 #include "os-proto.h"
  61 #endif
  62
  63 #ifdef AF_PACKET
  64 # ifdef __Lynx__
  65 #  include <netpacket/if_packet.h>      /* LynxOS */
  66 # else
  67 #  include <linux/if_packet.h>          /* Linux */
  68 # endif
  69 #endif
  70
  71 /*
  72  * This is fun.
  73  *
  74  * In older BSD systems, socket addresses were fixed-length, and
  75  * "sizeof (struct sockaddr)" gave the size of the structure.
  76  * All addresses fit within a "struct sockaddr".
  77  *
  78  * In newer BSD systems, the socket address is variable-length, and
  79  * there's an "sa_len" field giving the length of the structure;
  80  * this allows socket addresses to be longer than 2 bytes of family
  81  * and 14 bytes of data.
  82  *
  83  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  84  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  85  * than "struct sockaddr"), and some use the new BSD scheme.
  86  *
  87  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  88  * macro that determines the size based on the address family.  Other
  89  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  90  * but not in the final version).  On the latter systems, we explicitly
  91  * check the AF_ type to determine the length; we assume that on
  92  * all those systems we have "struct sockaddr_storage".
  93  */
  94 #ifndef SA_LEN
  95 #ifdef HAVE_SOCKADDR_SA_LEN
  96 #define SA_LEN(addr)    ((addr)->sa_len)
  97 #else /* HAVE_SOCKADDR_SA_LEN */
  98 #ifdef HAVE_SOCKADDR_STORAGE
  99 static size_t
 100 get_sa_len(struct sockaddr *addr)
 101 {
 102         switch (addr->sa_family) {
 103
 104 #ifdef AF_INET
 105         case AF_INET:
 106                 return (sizeof (struct sockaddr_in));
 107 #endif
 108
 109 #ifdef AF_INET6
 110         case AF_INET6:
 111                 return (sizeof (struct sockaddr_in6));
 112 #endif
 113
 114 #ifdef AF_PACKET
 115         case AF_PACKET:
 116                 return (sizeof (struct sockaddr_ll));
 117 #endif
 118
 119         default:
 120                 return (sizeof (struct sockaddr));
 121         }
 122 }
 123 #define SA_LEN(addr)    (get_sa_len(addr))
 124 #else /* HAVE_SOCKADDR_STORAGE */
 125 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 126 #endif /* HAVE_SOCKADDR_STORAGE */
 127 #endif /* HAVE_SOCKADDR_SA_LEN */
 128 #endif /* SA_LEN */
 129
 130 /*
 131  * Get a list of all interfaces that are up and that we can open.
 132  * Returns -1 on error, 0 otherwise.
 133  * The list, as returned through "alldevsp", may be null if no interfaces
 134  * were up and could be opened.
 135  *
 136  * This is the implementation used on platforms that have "getifaddrs()".
 137  */
 138 int
 139 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 140 {
 141         pcap_if_t *devlist = NULL;
 142         struct ifaddrs *ifap, *ifa;
 143         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 144         size_t addr_size, broadaddr_size, dstaddr_size;
 145         int ret = 0;
 146         char *p, *q;
 147
 148         /*
 149          * Get the list of interface addresses.
 150          *
 151          * Note: this won't return information about interfaces
 152          * with no addresses; are there any such interfaces
 153          * that would be capable of receiving packets?
 154          * (Interfaces incapable of receiving packets aren't
 155          * very interesting from libpcap's point of view.)
 156          *
 157          * LAN interfaces will probably have link-layer
 158          * addresses; I don't know whether all implementations
 159          * of "getifaddrs()" now, or in the future, will return
 160          * those.
 161          */
 162         if (getifaddrs(&ifap) != 0) {
 163                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 164                     "getifaddrs: %s", pcap_strerror(errno));
 165                 return (-1);
 166         }
 167         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 168                 /*
 169                  * Is this interface up?
 170                  */
 171                 if (!(ifa->ifa_flags & IFF_UP)) {
 172                         /*
 173                          * No, so don't add it to the list.
 174                          */
 175                         continue;
 176                 }
 177
 178                 /*
 179                  * "ifa_addr" was apparently null on at least one
 180                  * interface on some system.
 181                  *
 182                  * "ifa_broadaddr" may be non-null even on
 183                  * non-broadcast interfaces, and was null on
 184                  * at least one OpenBSD 3.4 system on at least
 185                  * one interface with IFF_BROADCAST set.
 186                  *
 187                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 188                  * system, non-null on a non-point-to-point
 189                  * interface.
 190                  *
 191                  * Therefore, we supply the address and netmask only
 192                  * if "ifa_addr" is non-null (if there's no address,
 193                  * there's obviously no netmask), and supply the
 194                  * broadcast and destination addresses if the appropriate
 195                  * flag is set *and* the appropriate "ifa_" entry doesn't
 196                  * evaluate to a null pointer.
 197                  */
 198                 if (ifa->ifa_addr != NULL) {
 199                         addr = ifa->ifa_addr;
 200                         addr_size = SA_LEN(addr);
 201                         netmask = ifa->ifa_netmask;
 202                 } else {
 203                         addr = NULL;
 204                         addr_size = 0;
 205                         netmask = NULL;
 206                 }
 207                 if (ifa->ifa_flags & IFF_BROADCAST &&
 208                     ifa->ifa_broadaddr != NULL) {
 209                         broadaddr = ifa->ifa_broadaddr;
 210                         broadaddr_size = SA_LEN(broadaddr);
 211                 } else {
 212                         broadaddr = NULL;
 213                         broadaddr_size = 0;
 214                 }
 215                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 216                     ifa->ifa_dstaddr != NULL) {
 217                         dstaddr = ifa->ifa_dstaddr;
 218                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 219                 } else {
 220                         dstaddr = NULL;
 221                         dstaddr_size = 0;
 222                 }
 223
 224                 /*
 225                  * If this entry has a colon followed by a number at
 226                  * the end, we assume it's a logical interface.  Those
 227                  * are just the way you assign multiple IP addresses to
 228                  * a real interface on Linux, so an entry for a logical
 229                  * interface should be treated like the entry for the
 230                  * real interface; we do that by stripping off the ":"
 231                  * and the number.
 232                  *
 233                  * XXX - should we do this only on Linux?
 234                  */
 235                 p = strchr(ifa->ifa_name, ':');
 236                 if (p != NULL) {
 237                         /*
 238                          * We have a ":"; is it followed by a number?
 239                          */
 240                         q = p + 1;
 241                         while (isdigit((unsigned char)*q))
 242                                 q++;
 243                         if (*q == '\0') {
 244                                 /*
 245                                  * All digits after the ":" until the end.
 246                                  * Strip off the ":" and everything after
 247                                  * it.
 248                                  */
 249                                *p = '\0';
 250                         }
 251                 }
 252
 253                 /*
 254                  * Add information for this address to the list.
 255                  */
 256                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 257                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 258                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 259                     errbuf) < 0) {
 260                         ret = -1;
 261                         break;
 262                 }
 263         }
 264
 265         freeifaddrs(ifap);
 266
 267         if (ret != -1) {
 268                 /*
 269                  * We haven't had any errors yet; do any platform-specific
 270                  * operations to add devices.
 271                  */
 272                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 273                         ret = -1;
 274         }
 275
 276         if (ret == -1) {
 277                 /*
 278                  * We had an error; free the list we've been constructing.
 279                  */
 280                 if (devlist != NULL) {
 281                         pcap_freealldevs(devlist);
 282                         devlist = NULL;
 283                 }
 284         }
 285
 286         *alldevsp = devlist;
 287         return (ret);
 288 }