external/bsd/libpcap/dist/fad-getad.c

   1 /*      $NetBSD: fad-getad.c,v 1.2 2014/11/19 19:33:30 christos Exp $   */
   2
   3 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
   4 /*
   5  * Copyright (c) 1994, 1995, 1996, 1997, 1998
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the Computer Systems
  19  *      Engineering Group at Lawrence Berkeley Laboratory.
  20  * 4. Neither the name of the University nor of the Laboratory may be used
  21  *    to endorse or promote products derived from this software without
  22  *    specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __RCSID("$NetBSD: fad-getad.c,v 1.2 2014/11/19 19:33:30 christos Exp $");
  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 /*
  64  * We don't do this on Solaris 11 and later, as it appears there aren't
  65  * any AF_PACKET addresses on interfaces, so we don't need this, and
  66  * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
  67  * and their definitions of some data structures collide.
  68  */
  69 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
  70 # ifdef HAVE_NETPACKET_PACKET_H
  71 /* Linux distributions with newer glibc */
  72 #  include <netpacket/packet.h>
  73 # else /* HAVE_NETPACKET_PACKET_H */
  74 /* LynxOS, Linux distributions with older glibc */
  75 # ifdef __Lynx__
  76 /* LynxOS */
  77 #  include <netpacket/if_packet.h>
  78 # else /* __Lynx__ */
  79 /* Linux */
  80 #  include <linux/types.h>
  81 #  include <linux/if_packet.h>
  82 # endif /* __Lynx__ */
  83 # endif /* HAVE_NETPACKET_PACKET_H */
  84 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
  85
  86 /*
  87  * This is fun.
  88  *
  89  * In older BSD systems, socket addresses were fixed-length, and
  90  * "sizeof (struct sockaddr)" gave the size of the structure.
  91  * All addresses fit within a "struct sockaddr".
  92  *
  93  * In newer BSD systems, the socket address is variable-length, and
  94  * there's an "sa_len" field giving the length of the structure;
  95  * this allows socket addresses to be longer than 2 bytes of family
  96  * and 14 bytes of data.
  97  *
  98  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  99  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
 100  * than "struct sockaddr"), and some use the new BSD scheme.
 101  *
 102  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
 103  * macro that determines the size based on the address family.  Other
 104  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
 105  * but not in the final version).  On the latter systems, we explicitly
 106  * check the AF_ type to determine the length; we assume that on
 107  * all those systems we have "struct sockaddr_storage".
 108  */
 109 #ifndef SA_LEN
 110 #ifdef HAVE_SOCKADDR_SA_LEN
 111 #define SA_LEN(addr)    ((addr)->sa_len)
 112 #else /* HAVE_SOCKADDR_SA_LEN */
 113 #ifdef HAVE_SOCKADDR_STORAGE
 114 static size_t
 115 get_sa_len(struct sockaddr *addr)
 116 {
 117         switch (addr->sa_family) {
 118
 119 #ifdef AF_INET
 120         case AF_INET:
 121                 return (sizeof (struct sockaddr_in));
 122 #endif
 123
 124 #ifdef AF_INET6
 125         case AF_INET6:
 126                 return (sizeof (struct sockaddr_in6));
 127 #endif
 128
 129 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
 130         case AF_PACKET:
 131                 return (sizeof (struct sockaddr_ll));
 132 #endif
 133
 134         default:
 135                 return (sizeof (struct sockaddr));
 136         }
 137 }
 138 #define SA_LEN(addr)    (get_sa_len(addr))
 139 #else /* HAVE_SOCKADDR_STORAGE */
 140 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 141 #endif /* HAVE_SOCKADDR_STORAGE */
 142 #endif /* HAVE_SOCKADDR_SA_LEN */
 143 #endif /* SA_LEN */
 144
 145 /*
 146  * Get a list of all interfaces that are up and that we can open.
 147  * Returns -1 on error, 0 otherwise.
 148  * The list, as returned through "alldevsp", may be null if no interfaces
 149  * could be opened.
 150  */
 151 int
 152 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
 153 {
 154         pcap_if_t *devlist = NULL;
 155         struct ifaddrs *ifap, *ifa;
 156         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 157         size_t addr_size, broadaddr_size, dstaddr_size;
 158         int ret = 0;
 159         char *p, *q;
 160
 161         /*
 162          * Get the list of interface addresses.
 163          *
 164          * Note: this won't return information about interfaces
 165          * with no addresses, so, if a platform has interfaces
 166          * with no interfaces on which traffic can be captured,
 167          * we must check for those interfaces as well (see, for
 168          * example, what's done on Linux).
 169          *
 170          * LAN interfaces will probably have link-layer
 171          * addresses; I don't know whether all implementations
 172          * of "getifaddrs()" now, or in the future, will return
 173          * those.
 174          */
 175         if (getifaddrs(&ifap) != 0) {
 176                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 177                     "getifaddrs: %s", pcap_strerror(errno));
 178                 return (-1);
 179         }
 180         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 181                 /*
 182                  * "ifa_addr" was apparently null on at least one
 183                  * interface on some system.  Therefore, we supply
 184                  * the address and netmask only if "ifa_addr" is
 185                  * non-null (if there's no address, there's obviously
 186                  * no netmask).
 187                  */
 188                 if (ifa->ifa_addr != NULL) {
 189                         addr = ifa->ifa_addr;
 190                         addr_size = SA_LEN(addr);
 191                         netmask = ifa->ifa_netmask;
 192                 } else {
 193                         addr = NULL;
 194                         addr_size = 0;
 195                         netmask = NULL;
 196                 }
 197
 198                 /*
 199                  * Note that, on some platforms, ifa_broadaddr and
 200                  * ifa_dstaddr could be the same field (true on at
 201                  * least some versions of *BSD and OS X), so we
 202                  * can't just check whether the broadcast address
 203                  * is null and add it if so and check whether the
 204                  * destination address is null and add it if so.
 205                  *
 206                  * Therefore, we must also check the IFF_BROADCAST
 207                  * flag, and only add a broadcast address if it's
 208                  * set, and check the IFF_POINTTOPOINT flag, and
 209                  * only add a destination address if it's set (as
 210                  * per man page recommendations on some of those
 211                  * platforms).
 212                  */
 213                 if (ifa->ifa_flags & IFF_BROADCAST &&
 214                     ifa->ifa_broadaddr != NULL) {
 215                         broadaddr = ifa->ifa_broadaddr;
 216                         broadaddr_size = SA_LEN(broadaddr);
 217                 } else {
 218                         broadaddr = NULL;
 219                         broadaddr_size = 0;
 220                 }
 221                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 222                     ifa->ifa_dstaddr != NULL) {
 223                         dstaddr = ifa->ifa_dstaddr;
 224                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 225                 } else {
 226                         dstaddr = NULL;
 227                         dstaddr_size = 0;
 228                 }
 229
 230                 /*
 231                  * If this entry has a colon followed by a number at
 232                  * the end, we assume it's a logical interface.  Those
 233                  * are just the way you assign multiple IP addresses to
 234                  * a real interface on Linux, so an entry for a logical
 235                  * interface should be treated like the entry for the
 236                  * real interface; we do that by stripping off the ":"
 237                  * and the number.
 238                  *
 239                  * XXX - should we do this only on Linux?
 240                  */
 241                 p = strchr(ifa->ifa_name, ':');
 242                 if (p != NULL) {
 243                         /*
 244                          * We have a ":"; is it followed by a number?
 245                          */
 246                         q = p + 1;
 247                         while (isdigit((unsigned char)*q))
 248                                 q++;
 249                         if (*q == '\0') {
 250                                 /*
 251                                  * All digits after the ":" until the end.
 252                                  * Strip off the ":" and everything after
 253                                  * it.
 254                                  */
 255                                *p = '\0';
 256                         }
 257                 }
 258
 259                 /*
 260                  * Add information for this address to the list.
 261                  */
 262                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 263                     ifa->ifa_flags, addr, addr_size, netmask, addr_size,
 264                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 265                     errbuf) < 0) {
 266                         ret = -1;
 267                         break;
 268                 }
 269         }
 270
 271         freeifaddrs(ifap);
 272
 273         if (ret == -1) {
 274                 /*
 275                  * We had an error; free the list we've been constructing.
 276                  */
 277                 if (devlist != NULL) {
 278                         pcap_freealldevs(devlist);
 279                         devlist = NULL;
 280                 }
 281         }
 282
 283         *alldevsp = devlist;
 284         return (ret);
 285 }