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