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 #ifdef HAVE_CONFIG_H
  36 #include "config.h"
  37 #endif
  38
  39 #include <sys/types.h>
  40 #include <sys/socket.h>
  41 #include <netinet/in.h>
  42
  43 #include <net/if.h>
  44
  45 #include <ctype.h>
  46 #include <errno.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <ifaddrs.h>
  51
  52 #include "pcap-int.h"
  53
  54 #ifdef HAVE_OS_PROTO_H
  55 #include "os-proto.h"
  56 #endif
  57
  58 /*
  59  * We don't do this on Solaris 11 and later, as it appears there aren't
  60  * any AF_PACKET addresses on interfaces, so we don't need this, and
  61  * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
  62  * and their definitions of some data structures collide.
  63  */
  64 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
  65 # ifdef HAVE_NETPACKET_PACKET_H
  66 /* Linux distributions with newer glibc */
  67 #  include <netpacket/packet.h>
  68 # else /* HAVE_NETPACKET_PACKET_H */
  69 /* LynxOS, Linux distributions with older glibc */
  70 # ifdef __Lynx__
  71 /* LynxOS */
  72 #  include <netpacket/if_packet.h>
  73 # else /* __Lynx__ */
  74 /* Linux */
  75 #  include <linux/types.h>
  76 #  include <linux/if_packet.h>
  77 # endif /* __Lynx__ */
  78 # endif /* HAVE_NETPACKET_PACKET_H */
  79 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
  80
  81 /*
  82  * This is fun.
  83  *
  84  * In older BSD systems, socket addresses were fixed-length, and
  85  * "sizeof (struct sockaddr)" gave the size of the structure.
  86  * All addresses fit within a "struct sockaddr".
  87  *
  88  * In newer BSD systems, the socket address is variable-length, and
  89  * there's an "sa_len" field giving the length of the structure;
  90  * this allows socket addresses to be longer than 2 bytes of family
  91  * and 14 bytes of data.
  92  *
  93  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  94  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  95  * than "struct sockaddr"), and some use the new BSD scheme.
  96  *
  97  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
  98  * macro that determines the size based on the address family.  Other
  99  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
 100  * but not in the final version).  On the latter systems, we explicitly
 101  * check the AF_ type to determine the length; we assume that on
 102  * all those systems we have "struct sockaddr_storage".
 103  */
 104 #ifndef SA_LEN
 105 #ifdef HAVE_SOCKADDR_SA_LEN
 106 #define SA_LEN(addr)    ((addr)->sa_len)
 107 #else /* HAVE_SOCKADDR_SA_LEN */
 108 #ifdef HAVE_SOCKADDR_STORAGE
 109 static size_t
 110 get_sa_len(struct sockaddr *addr)
 111 {
 112         switch (addr->sa_family) {
 113
 114 #ifdef AF_INET
 115         case AF_INET:
 116                 return (sizeof (struct sockaddr_in));
 117 #endif
 118
 119 #ifdef AF_INET6
 120         case AF_INET6:
 121                 return (sizeof (struct sockaddr_in6));
 122 #endif
 123
 124 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
 125         case AF_PACKET:
 126                 return (sizeof (struct sockaddr_ll));
 127 #endif
 128
 129         default:
 130                 return (sizeof (struct sockaddr));
 131         }
 132 }
 133 #define SA_LEN(addr)    (get_sa_len(addr))
 134 #else /* HAVE_SOCKADDR_STORAGE */
 135 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 136 #endif /* HAVE_SOCKADDR_STORAGE */
 137 #endif /* HAVE_SOCKADDR_SA_LEN */
 138 #endif /* SA_LEN */
 139
 140 /*
 141  * Get a list of all interfaces that are up and that we can open.
 142  * Returns -1 on error, 0 otherwise.
 143  * The list, as returned through "alldevsp", may be null if no interfaces
 144  * could be opened.
 145  */
 146 int
 147 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf,
 148     int (*check_usable)(const char *))
 149 {
 150         pcap_if_t *devlist = NULL;
 151         struct ifaddrs *ifap, *ifa;
 152         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 153         size_t addr_size, broadaddr_size, dstaddr_size;
 154         int ret = 0;
 155         char *p, *q;
 156
 157         /*
 158          * Get the list of interface addresses.
 159          *
 160          * Note: this won't return information about interfaces
 161          * with no addresses, so, if a platform has interfaces
 162          * with no interfaces on which traffic can be captured,
 163          * we must check for those interfaces as well (see, for
 164          * example, what's done on Linux).
 165          *
 166          * LAN interfaces will probably have link-layer
 167          * addresses; I don't know whether all implementations
 168          * of "getifaddrs()" now, or in the future, will return
 169          * those.
 170          */
 171         if (getifaddrs(&ifap) != 0) {
 172                 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 173                     "getifaddrs: %s", pcap_strerror(errno));
 174                 return (-1);
 175         }
 176         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 177                 /*
 178                  * If this entry has a colon followed by a number at
 179                  * the end, we assume it's a logical interface.  Those
 180                  * are just the way you assign multiple IP addresses to
 181                  * a real interface on Linux, so an entry for a logical
 182                  * interface should be treated like the entry for the
 183                  * real interface; we do that by stripping off the ":"
 184                  * and the number.
 185                  *
 186                  * XXX - should we do this only on Linux?
 187                  */
 188                 p = strchr(ifa->ifa_name, ':');
 189                 if (p != NULL) {
 190                         /*
 191                          * We have a ":"; is it followed by a number?
 192                          */
 193                         q = p + 1;
 194                         while (isdigit((unsigned char)*q))
 195                                 q++;
 196                         if (*q == '\0') {
 197                                 /*
 198                                  * All digits after the ":" until the end.
 199                                  * Strip off the ":" and everything after
 200                                  * it.
 201                                  */
 202                                *p = '\0';
 203                         }
 204                 }
 205
 206                 /*
 207                  * Can we capture on this device?
 208                  */
 209                 if (!(*check_usable)(ifa->ifa_name)) {
 210                         /*
 211                          * No.
 212                          */
 213                         continue;
 214                 }
 215
 216                 /*
 217                  * "ifa_addr" was apparently null on at least one
 218                  * interface on some system.  Therefore, we supply
 219                  * the address and netmask only if "ifa_addr" is
 220                  * non-null (if there's no address, there's obviously
 221                  * no netmask).
 222                  */
 223                 if (ifa->ifa_addr != NULL) {
 224                         addr = ifa->ifa_addr;
 225                         addr_size = SA_LEN(addr);
 226                         netmask = ifa->ifa_netmask;
 227                 } else {
 228                         addr = NULL;
 229                         addr_size = 0;
 230                         netmask = NULL;
 231                 }
 232
 233                 /*
 234                  * Note that, on some platforms, ifa_broadaddr and
 235                  * ifa_dstaddr could be the same field (true on at
 236                  * least some versions of *BSD and OS X), so we
 237                  * can't just check whether the broadcast address
 238                  * is null and add it if so and check whether the
 239                  * destination address is null and add it if so.
 240                  *
 241                  * Therefore, we must also check the IFF_BROADCAST
 242                  * flag, and only add a broadcast address if it's
 243                  * set, and check the IFF_POINTTOPOINT flag, and
 244                  * only add a destination address if it's set (as
 245                  * per man page recommendations on some of those
 246                  * platforms).
 247                  */
 248                 if (ifa->ifa_flags & IFF_BROADCAST &&
 249                     ifa->ifa_broadaddr != NULL) {
 250                         broadaddr = ifa->ifa_broadaddr;
 251                         broadaddr_size = SA_LEN(broadaddr);
 252                 } else {
 253                         broadaddr = NULL;
 254                         broadaddr_size = 0;
 255                 }
 256                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 257                     ifa->ifa_dstaddr != NULL) {
 258                         dstaddr = ifa->ifa_dstaddr;
 259                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 260                 } else {
 261                         dstaddr = NULL;
 262                         dstaddr_size = 0;
 263                 }
 264
 265                 /*
 266                  * Add information for this address to the list.
 267                  */
 268                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 269                     if_flags_to_pcap_flags(ifa->ifa_name, ifa->ifa_flags),
 270                     addr, addr_size, netmask, addr_size,
 271                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 272                     errbuf) < 0) {
 273                         ret = -1;
 274                         break;
 275                 }
 276         }
 277
 278         freeifaddrs(ifap);
 279
 280         if (ret == -1) {
 281                 /*
 282                  * We had an error; free the list we've been constructing.
 283                  */
 284                 if (devlist != NULL) {
 285                         pcap_freealldevs(devlist);
 286                         devlist = NULL;
 287                 }
 288         }
 289
 290         *alldevsp = devlist;
 291         return (ret);
 292 }