dist/libpcap/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: /pub/NetBSD/misc/repositories/cvsroot/src/dist/libpcap/fad-getad.c,v 1.1.1.1 2006/02/27 15:45:44 drochner 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 # include <linux/if_packet.h>
  65 #endif
  66
  67 /*
  68  * This is fun.
  69  *
  70  * In older BSD systems, socket addresses were fixed-length, and
  71  * "sizeof (struct sockaddr)" gave the size of the structure.
  72  * All addresses fit within a "struct sockaddr".
  73  *
  74  * In newer BSD systems, the socket address is variable-length, and
  75  * there's an "sa_len" field giving the length of the structure;
  76  * this allows socket addresses to be longer than 2 bytes of family
  77  * and 14 bytes of data.
  78  *
  79  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  80  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  81  * than "struct sockaddr"), and some use the new BSD scheme.
  82  *
  83  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  84  * macro that determines the size based on the address family.  Other
  85  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  86  * but not in the final version).  On the latter systems, we explicitly
  87  * check the AF_ type to determine the length; we assume that on
  88  * all those systems we have "struct sockaddr_storage".
  89  */
  90 #ifndef SA_LEN
  91 #ifdef HAVE_SOCKADDR_SA_LEN
  92 #define SA_LEN(addr)    ((addr)->sa_len)
  93 #else /* HAVE_SOCKADDR_SA_LEN */
  94 #ifdef HAVE_SOCKADDR_STORAGE
  95 static size_t
  96 get_sa_len(struct sockaddr *addr)
  97 {
  98         switch (addr->sa_family) {
  99
 100 #ifdef AF_INET
 101         case AF_INET:
 102                 return (sizeof (struct sockaddr_in));
 103 #endif
 104
 105 #ifdef AF_INET6
 106         case AF_INET6:
 107                 return (sizeof (struct sockaddr_in6));
 108 #endif
 109
 110 #ifdef AF_PACKET
 111         case AF_PACKET:
 112                 return (sizeof (struct sockaddr_ll));
 113 #endif
 114
 115         default:
 116                 return (sizeof (struct sockaddr));
 117         }
 118 }
 119 #define SA_LEN(addr)    (get_sa_len(addr))
 120 #else /* HAVE_SOCKADDR_STORAGE */
 121 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 122 #endif /* HAVE_SOCKADDR_STORAGE */
 123 #endif /* HAVE_SOCKADDR_SA_LEN */
 124 #endif /* SA_LEN */
 125
 126 /*
 127  * Get a list of all interfaces that are up and that we can open.
 128  * Returns -1 on error, 0 otherwise.
 129  * The list, as returned through "alldevsp", may be null if no interfaces
 130  * were up and could be opened.
 131  *
 132  * This is the implementation used on platforms that have "getifaddrs()".
 133  */
 134 int
 135 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 136 {
 137         pcap_if_t *devlist = NULL;
 138         struct ifaddrs *ifap, *ifa;
 139         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 140         size_t addr_size, broadaddr_size, dstaddr_size;
 141         int ret = 0;
 142         char *p, *q;
 143
 144         /*
 145          * Get the list of interface addresses.
 146          *
 147          * Note: this won't return information about interfaces
 148          * with no addresses; are there any such interfaces
 149          * that would be capable of receiving packets?
 150          * (Interfaces incapable of receiving packets aren't
 151          * very interesting from libpcap's point of view.)
 152          *
 153          * LAN interfaces will probably have link-layer
 154          * addresses; I don't know whether all implementations
 155          * of "getifaddrs()" now, or in the future, will return
 156          * those.
 157          */
 158         if (getifaddrs(&ifap) != 0) {
 159                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 160                     "getifaddrs: %s", pcap_strerror(errno));
 161                 return (-1);
 162         }
 163         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 164                 /*
 165                  * Is this interface up?
 166                  */
 167                 if (!(ifa->ifa_flags & IFF_UP)) {
 168                         /*
 169                          * No, so don't add it to the list.
 170                          */
 171                         continue;
 172                 }
 173
 174                 /*
 175                  * "ifa_addr" was apparently null on at least one
 176                  * interface on some system.
 177                  *
 178                  * "ifa_broadaddr" may be non-null even on
 179                  * non-broadcast interfaces, and was null on
 180                  * at least one OpenBSD 3.4 system on at least
 181                  * one interface with IFF_BROADCAST set.
 182                  *
 183                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 184                  * system, non-null on a non-point-to-point
 185                  * interface.
 186                  *
 187                  * Therefore, we supply the address and netmask only
 188                  * if "ifa_addr" is non-null (if there's no address,
 189                  * there's obviously no netmask), and supply the
 190                  * broadcast and destination addresses if the appropriate
 191                  * flag is set *and* the appropriate "ifa_" entry doesn't
 192                  * evaluate to a null pointer.
 193                  */
 194                 if (ifa->ifa_addr != NULL) {
 195                         addr = ifa->ifa_addr;
 196                         addr_size = SA_LEN(addr);
 197                         netmask = ifa->ifa_netmask;
 198                 } else {
 199                         addr = NULL;
 200                         addr_size = 0;
 201                         netmask = NULL;
 202                 }
 203                 if (ifa->ifa_flags & IFF_BROADCAST &&
 204                     ifa->ifa_broadaddr != NULL) {
 205                         broadaddr = ifa->ifa_broadaddr;
 206                         broadaddr_size = SA_LEN(broadaddr);
 207                 } else {
 208                         broadaddr = NULL;
 209                         broadaddr_size = 0;
 210                 }
 211                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 212                     ifa->ifa_dstaddr != NULL) {
 213                         dstaddr = ifa->ifa_dstaddr;
 214                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 215                 } else {
 216                         dstaddr = NULL;
 217                         dstaddr_size = 0;
 218                 }
 219
 220                 /*
 221                  * If this entry has a colon followed by a number at
 222                  * the end, we assume it's a logical interface.  Those
 223                  * are just the way you assign multiple IP addresses to
 224                  * a real interface on Linux, so an entry for a logical
 225                  * interface should be treated like the entry for the
 226                  * real interface; we do that by stripping off the ":"
 227                  * and the number.
 228                  *
 229                  * XXX - should we do this only on Linux?
 230                  */
 231                 p = strchr(ifa->ifa_name, ':');
 232                 if (p != NULL) {
 233                         /*
 234                          * We have a ":"; is it followed by a number?
 235                          */
 236                         q = p + 1;
 237                         while (isdigit((unsigned char)*q))
 238                                 q++;
 239                         if (*q == '\0') {
 240                                 /*
 241                                  * All digits after the ":" until the end.
 242                                  * Strip off the ":" and everything after
 243                                  * it.
 244                                  */
 245                                *p = '\0';
 246                         }
 247                 }
 248
 249                 /*
 250                  * Add information for this address to the list.
 251                  */
 252                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 253                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 254                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 255                     errbuf) < 0) {
 256                         ret = -1;
 257                         break;
 258                 }
 259         }
 260
 261         freeifaddrs(ifap);
 262
 263         if (ret != -1) {
 264                 /*
 265                  * We haven't had any errors yet; do any platform-specific
 266                  * operations to add devices.
 267                  */
 268                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 269                         ret = -1;
 270         }
 271
 272         if (ret == -1) {
 273                 /*
 274                  * We had an error; free the list we've been constructing.
 275                  */
 276                 if (devlist != NULL) {
 277                         pcap_freealldevs(devlist);
 278                         devlist = NULL;
 279                 }
 280         }
 281
 282         *alldevsp = devlist;
 283         return (ret);
 284 }