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