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 1.10 2004-11-04 07:26:04 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 <errno.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <ifaddrs.h>
  54
  55 #include "pcap-int.h"
  56
  57 #ifdef HAVE_OS_PROTO_H
  58 #include "os-proto.h"
  59 #endif
  60
  61 #ifdef AF_PACKET
  62 # include <linux/if_packet.h>
  63 #endif
  64
  65 /*
  66  * This is fun.
  67  *
  68  * In older BSD systems, socket addresses were fixed-length, and
  69  * "sizeof (struct sockaddr)" gave the size of the structure.
  70  * All addresses fit within a "struct sockaddr".
  71  *
  72  * In newer BSD systems, the socket address is variable-length, and
  73  * there's an "sa_len" field giving the length of the structure;
  74  * this allows socket addresses to be longer than 2 bytes of family
  75  * and 14 bytes of data.
  76  *
  77  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  78  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  79  * than "struct sockaddr"), and some use the new BSD scheme.
  80  *
  81  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  82  * macro that determines the size based on the address family.  Other
  83  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  84  * but not in the final version).  On the latter systems, we explicitly
  85  * check the AF_ type to determine the length; we assume that on
  86  * all those systems we have "struct sockaddr_storage".
  87  */
  88 #ifndef SA_LEN
  89 #ifdef HAVE_SOCKADDR_SA_LEN
  90 #define SA_LEN(addr)    ((addr)->sa_len)
  91 #else /* HAVE_SOCKADDR_SA_LEN */
  92 #ifdef HAVE_SOCKADDR_STORAGE
  93 static size_t
  94 get_sa_len(struct sockaddr *addr)
  95 {
  96         switch (addr->sa_family) {
  97
  98 #ifdef AF_INET
  99         case AF_INET:
 100                 return (sizeof (struct sockaddr_in));
 101 #endif
 102
 103 #ifdef AF_INET6
 104         case AF_INET6:
 105                 return (sizeof (struct sockaddr_in6));
 106 #endif
 107
 108 #ifdef AF_PACKET
 109         case AF_PACKET:
 110                 return (sizeof (struct sockaddr_ll));
 111 #endif
 112
 113         default:
 114                 return (sizeof (struct sockaddr));
 115         }
 116 }
 117 #define SA_LEN(addr)    (get_sa_len(addr))
 118 #else /* HAVE_SOCKADDR_STORAGE */
 119 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 120 #endif /* HAVE_SOCKADDR_STORAGE */
 121 #endif /* HAVE_SOCKADDR_SA_LEN */
 122 #endif /* SA_LEN */
 123
 124 /*
 125  * Get a list of all interfaces that are up and that we can open.
 126  * Returns -1 on error, 0 otherwise.
 127  * The list, as returned through "alldevsp", may be null if no interfaces
 128  * were up and could be opened.
 129  *
 130  * This is the implementation used on platforms that have "getifaddrs()".
 131  */
 132 int
 133 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 134 {
 135         pcap_if_t *devlist = NULL;
 136         struct ifaddrs *ifap, *ifa;
 137         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 138         size_t addr_size, broadaddr_size, dstaddr_size;
 139         int ret = 0;
 140
 141         /*
 142          * Get the list of interface addresses.
 143          *
 144          * Note: this won't return information about interfaces
 145          * with no addresses; are there any such interfaces
 146          * that would be capable of receiving packets?
 147          * (Interfaces incapable of receiving packets aren't
 148          * very interesting from libpcap's point of view.)
 149          *
 150          * LAN interfaces will probably have link-layer
 151          * addresses; I don't know whether all implementations
 152          * of "getifaddrs()" now, or in the future, will return
 153          * those.
 154          */
 155         if (getifaddrs(&ifap) != 0) {
 156                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 157                     "getifaddrs: %s", pcap_strerror(errno));
 158                 return (-1);
 159         }
 160         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 161                 /*
 162                  * Is this interface up?
 163                  */
 164                 if (!(ifa->ifa_flags & IFF_UP)) {
 165                         /*
 166                          * No, so don't add it to the list.
 167                          */
 168                         continue;
 169                 }
 170
 171                 /*
 172                  * "ifa_addr" was apparently null on at least one
 173                  * interface on some system.
 174                  *
 175                  * "ifa_broadaddr" may be non-null even on
 176                  * non-broadcast interfaces, and was null on
 177                  * at least one OpenBSD 3.4 system on at least
 178                  * one interface with IFF_BROADCAST set.
 179                  *
 180                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 181                  * system, non-null on a non-point-to-point
 182                  * interface.
 183                  *
 184                  * Therefore, we supply the address and netmask only
 185                  * if "ifa_addr" is non-null (if there's no address,
 186                  * there's obviously no netmask), and supply the
 187                  * broadcast and destination addresses if the appropriate
 188                  * flag is set *and* the appropriate "ifa_" entry doesn't
 189                  * evaluate to a null pointer.
 190                  */
 191                 if (ifa->ifa_addr != NULL) {
 192                         addr = ifa->ifa_addr;
 193                         addr_size = SA_LEN(addr);
 194                         netmask = ifa->ifa_netmask;
 195                 } else {
 196                         addr = NULL;
 197                         addr_size = 0;
 198                         netmask = NULL;
 199                 }
 200                 if (ifa->ifa_flags & IFF_BROADCAST &&
 201                     ifa->ifa_broadaddr != NULL) {
 202                         broadaddr = ifa->ifa_broadaddr;
 203                         broadaddr_size = SA_LEN(broadaddr);
 204                 } else {
 205                         broadaddr = NULL;
 206                         broadaddr_size = 0;
 207                 }
 208                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 209                     ifa->ifa_dstaddr != NULL) {
 210                         dstaddr = ifa->ifa_dstaddr;
 211                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 212                 } else {
 213                         dstaddr = NULL;
 214                         dstaddr_size = 0;
 215                 }
 216
 217                 /*
 218                  * Add information for this address to the list.
 219                  */
 220                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 221                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 222                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 223                     errbuf) < 0) {
 224                         ret = -1;
 225                         break;
 226                 }
 227         }
 228
 229         freeifaddrs(ifap);
 230
 231         if (ret != -1) {
 232                 /*
 233                  * We haven't had any errors yet; do any platform-specific
 234                  * operations to add devices.
 235                  */
 236                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 237                         ret = -1;
 238         }
 239
 240         if (ret == -1) {
 241                 /*
 242                  * We had an error; free the list we've been constructing.
 243                  */
 244                 if (devlist != NULL) {
 245                         pcap_freealldevs(devlist);
 246                         devlist = NULL;
 247                 }
 248         }
 249
 250         *alldevsp = devlist;
 251         return (ret);
 252 }