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 1.9 2004-03-11 23:04:24 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 /*
  62  * This is fun.
  63  *
  64  * In older BSD systems, socket addresses were fixed-length, and
  65  * "sizeof (struct sockaddr)" gave the size of the structure.
  66  * All addresses fit within a "struct sockaddr".
  67  *
  68  * In newer BSD systems, the socket address is variable-length, and
  69  * there's an "sa_len" field giving the length of the structure;
  70  * this allows socket addresses to be longer than 2 bytes of family
  71  * and 14 bytes of data.
  72  *
  73  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  74  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  75  * than "struct sockaddr"), and some use the new BSD scheme.
  76  *
  77  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  78  * macro that determines the size based on the address family.  Other
  79  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
  80  * but not in the final version).  On the latter systems, we explicitly
  81  * check the AF_ type to determine the length; we assume that on
  82  * all those systems we have "struct sockaddr_storage".
  83  */
  84 #ifndef SA_LEN
  85 #ifdef HAVE_SOCKADDR_SA_LEN
  86 #define SA_LEN(addr)    ((addr)->sa_len)
  87 #else /* HAVE_SOCKADDR_SA_LEN */
  88 #ifdef HAVE_SOCKADDR_STORAGE
  89 static size_t
  90 get_sa_len(struct sockaddr *addr)
  91 {
  92         switch (addr->sa_family) {
  93
  94 #ifdef AF_INET
  95         case AF_INET:
  96                 return (sizeof (struct sockaddr_in));
  97 #endif
  98
  99 #ifdef AF_INET6
 100         case AF_INET6:
 101                 return (sizeof (struct sockaddr_in6));
 102 #endif
 103
 104         default:
 105                 return (sizeof (struct sockaddr));
 106         }
 107 }
 108 #define SA_LEN(addr)    (get_sa_len(addr))
 109 #else /* HAVE_SOCKADDR_STORAGE */
 110 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 111 #endif /* HAVE_SOCKADDR_STORAGE */
 112 #endif /* HAVE_SOCKADDR_SA_LEN */
 113 #endif /* SA_LEN */
 114
 115 /*
 116  * Get a list of all interfaces that are up and that we can open.
 117  * Returns -1 on error, 0 otherwise.
 118  * The list, as returned through "alldevsp", may be null if no interfaces
 119  * were up and could be opened.
 120  *
 121  * This is the implementation used on platforms that have "getifaddrs()".
 122  */
 123 int
 124 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 125 {
 126         pcap_if_t *devlist = NULL;
 127         struct ifaddrs *ifap, *ifa;
 128         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 129         size_t addr_size, broadaddr_size, dstaddr_size;
 130         int ret = 0;
 131
 132         /*
 133          * Get the list of interface addresses.
 134          *
 135          * Note: this won't return information about interfaces
 136          * with no addresses; are there any such interfaces
 137          * that would be capable of receiving packets?
 138          * (Interfaces incapable of receiving packets aren't
 139          * very interesting from libpcap's point of view.)
 140          *
 141          * LAN interfaces will probably have link-layer
 142          * addresses; I don't know whether all implementations
 143          * of "getifaddrs()" now, or in the future, will return
 144          * those.
 145          */
 146         if (getifaddrs(&ifap) != 0) {
 147                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 148                     "getifaddrs: %s", pcap_strerror(errno));
 149                 return (-1);
 150         }
 151         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 152                 /*
 153                  * Is this interface up?
 154                  */
 155                 if (!(ifa->ifa_flags & IFF_UP)) {
 156                         /*
 157                          * No, so don't add it to the list.
 158                          */
 159                         continue;
 160                 }
 161
 162                 /*
 163                  * "ifa_addr" was apparently null on at least one
 164                  * interface on some system.
 165                  *
 166                  * "ifa_broadaddr" may be non-null even on
 167                  * non-broadcast interfaces, and was null on
 168                  * at least one OpenBSD 3.4 system on at least
 169                  * one interface with IFF_BROADCAST set.
 170                  *
 171                  * "ifa_dstaddr" was, on at least one FreeBSD 4.1
 172                  * system, non-null on a non-point-to-point
 173                  * interface.
 174                  *
 175                  * Therefore, we supply the address and netmask only
 176                  * if "ifa_addr" is non-null (if there's no address,
 177                  * there's obviously no netmask), and supply the
 178                  * broadcast and destination addresses if the appropriate
 179                  * flag is set *and* the appropriate "ifa_" entry doesn't
 180                  * evaluate to a null pointer.
 181                  */
 182                 if (ifa->ifa_addr != NULL) {
 183                         addr = ifa->ifa_addr;
 184                         addr_size = SA_LEN(addr);
 185                         netmask = ifa->ifa_netmask;
 186                 } else {
 187                         addr = NULL;
 188                         addr_size = 0;
 189                         netmask = NULL;
 190                 }
 191                 if (ifa->ifa_flags & IFF_BROADCAST &&
 192                     ifa->ifa_broadaddr != NULL) {
 193                         broadaddr = ifa->ifa_broadaddr;
 194                         broadaddr_size = SA_LEN(broadaddr);
 195                 } else {
 196                         broadaddr = NULL;
 197                         broadaddr_size = 0;
 198                 }
 199                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 200                     ifa->ifa_dstaddr != NULL) {
 201                         dstaddr = ifa->ifa_dstaddr;
 202                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 203                 } else {
 204                         dstaddr = NULL;
 205                         dstaddr_size = 0;
 206                 }
 207
 208                 /*
 209                  * Add information for this address to the list.
 210                  */
 211                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 212                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 213                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 214                     errbuf) < 0) {
 215                         ret = -1;
 216                         break;
 217                 }
 218         }
 219
 220         freeifaddrs(ifap);
 221
 222         if (ret != -1) {
 223                 /*
 224                  * We haven't had any errors yet; do any platform-specific
 225                  * operations to add devices.
 226                  */
 227                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 228                         ret = -1;
 229         }
 230
 231         if (ret == -1) {
 232                 /*
 233                  * We had an error; free the list we've been constructing.
 234                  */
 235                 if (devlist != NULL) {
 236                         pcap_freealldevs(devlist);
 237                         devlist = NULL;
 238                 }
 239         }
 240
 241         *alldevsp = devlist;
 242         return (ret);
 243 }