The Tcpdump Group git mirrors - libpcap/blob - 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 1.12 2007-09-14 00:44:55 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 /* LynxOS */
  66 #  include <netpacket/if_packet.h>
  67 # else
  68 /* Linux */
  69 #  include <linux/types.h>
  70 #  include <linux/if_packet.h>
  71 # endif
  72 #endif
  73
  74 /*
  75  * This is fun.
  76  *
  77  * In older BSD systems, socket addresses were fixed-length, and
  78  * "sizeof (struct sockaddr)" gave the size of the structure.
  79  * All addresses fit within a "struct sockaddr".
  80  *
  81  * In newer BSD systems, the socket address is variable-length, and
  82  * there's an "sa_len" field giving the length of the structure;
  83  * this allows socket addresses to be longer than 2 bytes of family
  84  * and 14 bytes of data.
  85  *
  86  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  87  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  88  * than "struct sockaddr"), and some use the new BSD scheme.
  89  *
  90  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  91  * macro that determines the size based on the address family.  Other
  92  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  93  * but not in the final version).  On the latter systems, we explicitly
  94  * check the AF_ type to determine the length; we assume that on
  95  * all those systems we have "struct sockaddr_storage".
  96  */
  97 #ifndef SA_LEN
  98 #ifdef HAVE_SOCKADDR_SA_LEN
  99 #define SA_LEN(addr)    ((addr)->sa_len)
 100 #else /* HAVE_SOCKADDR_SA_LEN */
 101 #ifdef HAVE_SOCKADDR_STORAGE
 102 static size_t
 103 get_sa_len(struct sockaddr *addr)
 104 {
 105         switch (addr->sa_family) {
 106
 107 #ifdef AF_INET
 108         case AF_INET:
 109                 return (sizeof (struct sockaddr_in));
 110 #endif
 111
 112 #ifdef AF_INET6
 113         case AF_INET6:
 114                 return (sizeof (struct sockaddr_in6));
 115 #endif
 116
 117 #ifdef AF_PACKET
 118         case AF_PACKET:
 119                 return (sizeof (struct sockaddr_ll));
 120 #endif
 121
 122         default:
 123                 return (sizeof (struct sockaddr));
 124         }
 125 }
 126 #define SA_LEN(addr)    (get_sa_len(addr))
 127 #else /* HAVE_SOCKADDR_STORAGE */
 128 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 129 #endif /* HAVE_SOCKADDR_STORAGE */
 130 #endif /* HAVE_SOCKADDR_SA_LEN */
 131 #endif /* SA_LEN */
 132
 133 /*
 134  * Get a list of all interfaces that are up and that we can open.
 135  * Returns -1 on error, 0 otherwise.
 136  * The list, as returned through "alldevsp", may be null if no interfaces
 137  * were up and could be opened.
 138  *
 139  * This is the implementation used on platforms that have "getifaddrs()".
 140  */
 141 int
 142 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 143 {
 144         pcap_if_t *devlist = NULL;
 145         struct ifaddrs *ifap, *ifa;
 146         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 147         size_t addr_size, broadaddr_size, dstaddr_size;
 148         int ret = 0;
 149         char *p, *q;
 150
 151         /*
 152          * Get the list of interface addresses.
 153          *
 154          * Note: this won't return information about interfaces
 155          * with no addresses; are there any such interfaces
 156          * that would be capable of receiving packets?
 157          * (Interfaces incapable of receiving packets aren't
 158          * very interesting from libpcap's point of view.)
 159          *
 160          * LAN interfaces will probably have link-layer
 161          * addresses; I don't know whether all implementations
 162          * of "getifaddrs()" now, or in the future, will return
 163          * those.
 164          */
 165         if (getifaddrs(&ifap) != 0) {
 166                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 167                     "getifaddrs: %s", pcap_strerror(errno));
 168                 return (-1);
 169         }
 170         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 171                 /*
 172                  * Is this interface up?
 173                  */
 174                 if (!(ifa->ifa_flags & IFF_UP)) {
 175                         /*
 176                          * No, so don't add it to the list.
 177                          */
 178                         continue;
 179                 }
 180
 181                 /*
 182                  * "ifa_addr" was apparently null on at least one
 183                  * interface on some system.
 184                  *
 185                  * "ifa_broadaddr" may be non-null even on
 186                  * non-broadcast interfaces, and was null on
 187                  * at least one OpenBSD 3.4 system on at least
 188                  * one interface with IFF_BROADCAST set.
 189                  *
 190                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 191                  * system, non-null on a non-point-to-point
 192                  * interface.
 193                  *
 194                  * Therefore, we supply the address and netmask only
 195                  * if "ifa_addr" is non-null (if there's no address,
 196                  * there's obviously no netmask), and supply the
 197                  * broadcast and destination addresses if the appropriate
 198                  * flag is set *and* the appropriate "ifa_" entry doesn't
 199                  * evaluate to a null pointer.
 200                  */
 201                 if (ifa->ifa_addr != NULL) {
 202                         addr = ifa->ifa_addr;
 203                         addr_size = SA_LEN(addr);
 204                         netmask = ifa->ifa_netmask;
 205                 } else {
 206                         addr = NULL;
 207                         addr_size = 0;
 208                         netmask = NULL;
 209                 }
 210                 if (ifa->ifa_flags & IFF_BROADCAST &&
 211                     ifa->ifa_broadaddr != NULL) {
 212                         broadaddr = ifa->ifa_broadaddr;
 213                         broadaddr_size = SA_LEN(broadaddr);
 214                 } else {
 215                         broadaddr = NULL;
 216                         broadaddr_size = 0;
 217                 }
 218                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 219                     ifa->ifa_dstaddr != NULL) {
 220                         dstaddr = ifa->ifa_dstaddr;
 221                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 222                 } else {
 223                         dstaddr = NULL;
 224                         dstaddr_size = 0;
 225                 }
 226
 227                 /*
 228                  * If this entry has a colon followed by a number at
 229                  * the end, we assume it's a logical interface.  Those
 230                  * are just the way you assign multiple IP addresses to
 231                  * a real interface on Linux, so an entry for a logical
 232                  * interface should be treated like the entry for the
 233                  * real interface; we do that by stripping off the ":"
 234                  * and the number.
 235                  *
 236                  * XXX - should we do this only on Linux?
 237                  */
 238                 p = strchr(ifa->ifa_name, ':');
 239                 if (p != NULL) {
 240                         /*
 241                          * We have a ":"; is it followed by a number?
 242                          */
 243                         q = p + 1;
 244                         while (isdigit((unsigned char)*q))
 245                                 q++;
 246                         if (*q == '\0') {
 247                                 /*
 248                                  * All digits after the ":" until the end.
 249                                  * Strip off the ":" and everything after
 250                                  * it.
 251                                  */
 252                                *p = '\0';
 253                         }
 254                 }
 255
 256                 /*
 257                  * Add information for this address to the list.
 258                  */
 259                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 260                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 261                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 262                     errbuf) < 0) {
 263                         ret = -1;
 264                         break;
 265                 }
 266         }
 267
 268         freeifaddrs(ifap);
 269
 270         if (ret != -1) {
 271                 /*
 272                  * We haven't had any errors yet; do any platform-specific
 273                  * operations to add devices.
 274                  */
 275                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 276                         ret = -1;
 277         }
 278
 279         if (ret == -1) {
 280                 /*
 281                  * We had an error; free the list we've been constructing.
 282                  */
 283                 if (devlist != NULL) {
 284                         pcap_freealldevs(devlist);
 285                         devlist = NULL;
 286                 }
 287         }
 288
 289         *alldevsp = devlist;
 290         return (ret);
 291 }