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 HAVE_NETPACKET_PACKET_H
  65 #  include <netpacket/packet.h>
  66 # endif
  67 # ifdef HAVE_NETPACKET_IF_PACKET_H
  68 #  include <netpacket/if_packet.h>
  69 # endif
  70 # ifdef HAVE_LINUX_TYPES_H
  71 #  include <linux/types.h>
  72 # endif
  73 # ifdef HAVE_LINUX_IF_PACKET_H
  74 #  include <linux/if_packet.h>
  75 # endif
  76 #endif
  77
  78 /*
  79  * This is fun.
  80  *
  81  * In older BSD systems, socket addresses were fixed-length, and
  82  * "sizeof (struct sockaddr)" gave the size of the structure.
  83  * All addresses fit within a "struct sockaddr".
  84  *
  85  * In newer BSD systems, the socket address is variable-length, and
  86  * there's an "sa_len" field giving the length of the structure;
  87  * this allows socket addresses to be longer than 2 bytes of family
  88  * and 14 bytes of data.
  89  *
  90  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  91  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  92  * than "struct sockaddr"), and some use the new BSD scheme.
  93  *
  94  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  95  * macro that determines the size based on the address family.  Other
  96  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  97  * but not in the final version).  On the latter systems, we explicitly
  98  * check the AF_ type to determine the length; we assume that on
  99  * all those systems we have "struct sockaddr_storage".
 100  */
 101 #ifndef SA_LEN
 102 #ifdef HAVE_SOCKADDR_SA_LEN
 103 #define SA_LEN(addr)    ((addr)->sa_len)
 104 #else /* HAVE_SOCKADDR_SA_LEN */
 105 #ifdef HAVE_SOCKADDR_STORAGE
 106 static size_t
 107 get_sa_len(struct sockaddr *addr)
 108 {
 109         switch (addr->sa_family) {
 110
 111 #ifdef AF_INET
 112         case AF_INET:
 113                 return (sizeof (struct sockaddr_in));
 114 #endif
 115
 116 #ifdef AF_INET6
 117         case AF_INET6:
 118                 return (sizeof (struct sockaddr_in6));
 119 #endif
 120
 121 #ifdef AF_PACKET
 122         case AF_PACKET:
 123                 return (sizeof (struct sockaddr_ll));
 124 #endif
 125
 126         default:
 127                 return (sizeof (struct sockaddr));
 128         }
 129 }
 130 #define SA_LEN(addr)    (get_sa_len(addr))
 131 #else /* HAVE_SOCKADDR_STORAGE */
 132 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 133 #endif /* HAVE_SOCKADDR_STORAGE */
 134 #endif /* HAVE_SOCKADDR_SA_LEN */
 135 #endif /* SA_LEN */
 136
 137 /*
 138  * Get a list of all interfaces that are up and that we can open.
 139  * Returns -1 on error, 0 otherwise.
 140  * The list, as returned through "alldevsp", may be null if no interfaces
 141  * were up and could be opened.
 142  *
 143  * This is the implementation used on platforms that have "getifaddrs()".
 144  */
 145 int
 146 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 147 {
 148         pcap_if_t *devlist = NULL;
 149         struct ifaddrs *ifap, *ifa;
 150         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 151         size_t addr_size, broadaddr_size, dstaddr_size;
 152         int ret = 0;
 153         char *p, *q;
 154
 155         /*
 156          * Get the list of interface addresses.
 157          *
 158          * Note: this won't return information about interfaces
 159          * with no addresses; are there any such interfaces
 160          * that would be capable of receiving packets?
 161          * (Interfaces incapable of receiving packets aren't
 162          * very interesting from libpcap's point of view.)
 163          *
 164          * LAN interfaces will probably have link-layer
 165          * addresses; I don't know whether all implementations
 166          * of "getifaddrs()" now, or in the future, will return
 167          * those.
 168          */
 169         if (getifaddrs(&ifap) != 0) {
 170                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 171                     "getifaddrs: %s", pcap_strerror(errno));
 172                 return (-1);
 173         }
 174         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 175                 /*
 176                  * Is this interface up?
 177                  */
 178                 if (!(ifa->ifa_flags & IFF_UP)) {
 179                         /*
 180                          * No, so don't add it to the list.
 181                          */
 182                         continue;
 183                 }
 184
 185                 /*
 186                  * "ifa_addr" was apparently null on at least one
 187                  * interface on some system.
 188                  *
 189                  * "ifa_broadaddr" may be non-null even on
 190                  * non-broadcast interfaces, and was null on
 191                  * at least one OpenBSD 3.4 system on at least
 192                  * one interface with IFF_BROADCAST set.
 193                  *
 194                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 195                  * system, non-null on a non-point-to-point
 196                  * interface.
 197                  *
 198                  * Therefore, we supply the address and netmask only
 199                  * if "ifa_addr" is non-null (if there's no address,
 200                  * there's obviously no netmask), and supply the
 201                  * broadcast and destination addresses if the appropriate
 202                  * flag is set *and* the appropriate "ifa_" entry doesn't
 203                  * evaluate to a null pointer.
 204                  */
 205                 if (ifa->ifa_addr != NULL) {
 206                         addr = ifa->ifa_addr;
 207                         addr_size = SA_LEN(addr);
 208                         netmask = ifa->ifa_netmask;
 209                 } else {
 210                         addr = NULL;
 211                         addr_size = 0;
 212                         netmask = NULL;
 213                 }
 214                 if (ifa->ifa_flags & IFF_BROADCAST &&
 215                     ifa->ifa_broadaddr != NULL) {
 216                         broadaddr = ifa->ifa_broadaddr;
 217                         broadaddr_size = SA_LEN(broadaddr);
 218                 } else {
 219                         broadaddr = NULL;
 220                         broadaddr_size = 0;
 221                 }
 222                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 223                     ifa->ifa_dstaddr != NULL) {
 224                         dstaddr = ifa->ifa_dstaddr;
 225                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 226                 } else {
 227                         dstaddr = NULL;
 228                         dstaddr_size = 0;
 229                 }
 230
 231                 /*
 232                  * If this entry has a colon followed by a number at
 233                  * the end, we assume it's a logical interface.  Those
 234                  * are just the way you assign multiple IP addresses to
 235                  * a real interface on Linux, so an entry for a logical
 236                  * interface should be treated like the entry for the
 237                  * real interface; we do that by stripping off the ":"
 238                  * and the number.
 239                  *
 240                  * XXX - should we do this only on Linux?
 241                  */
 242                 p = strchr(ifa->ifa_name, ':');
 243                 if (p != NULL) {
 244                         /*
 245                          * We have a ":"; is it followed by a number?
 246                          */
 247                         q = p + 1;
 248                         while (isdigit((unsigned char)*q))
 249                                 q++;
 250                         if (*q == '\0') {
 251                                 /*
 252                                  * All digits after the ":" until the end.
 253                                  * Strip off the ":" and everything after
 254                                  * it.
 255                                  */
 256                                *p = '\0';
 257                         }
 258                 }
 259
 260                 /*
 261                  * Add information for this address to the list.
 262                  */
 263                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 264                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 265                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 266                     errbuf) < 0) {
 267                         ret = -1;
 268                         break;
 269                 }
 270         }
 271
 272         freeifaddrs(ifap);
 273
 274         if (ret != -1) {
 275                 /*
 276                  * We haven't had any errors yet; do any platform-specific
 277                  * operations to add devices.
 278                  */
 279                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 280                         ret = -1;
 281         }
 282
 283         if (ret == -1) {
 284                 /*
 285                  * We had an error; free the list we've been constructing.
 286                  */
 287                 if (devlist != NULL) {
 288                         pcap_freealldevs(devlist);
 289                         devlist = NULL;
 290                 }
 291         }
 292
 293         *alldevsp = devlist;
 294         return (ret);
 295 }