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 /*
  46  * NetBSD insists on having <net/if.h> pull in <net/dlt.h>, so that
  47  * including <net/if.h> defines a bunch of stuff we later define in our
  48  * pcap/dlt.h; those definitions will be different, if they haven't
  49  * picked up all of our changes yet.
  50  *
  51  * Undefine some of the offending items.
  52  */
  53 #ifdef __NetBSD__
  54 #undef DLT_USB                  /* we now define it as DLT_FREEBSD_USB */
  55 #undef DLT_MATCHING_MAX         /* we may define more DLT_ values than they do */
  56 #endif
  57
  58 #include <ctype.h>
  59 #include <errno.h>
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include <ifaddrs.h>
  64
  65 #include "pcap-int.h"
  66
  67 #ifdef HAVE_OS_PROTO_H
  68 #include "os-proto.h"
  69 #endif
  70
  71 /*
  72  * We don't do this on Solaris 11 and later, as it appears there aren't
  73  * any AF_PACKET addresses on interfaces, so we don't need this, and
  74  * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
  75  * and their definitions of some data structures collide.
  76  */
  77 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
  78 # ifdef HAVE_NETPACKET_PACKET_H
  79 /* Linux distributions with newer glibc */
  80 #  include <netpacket/packet.h>
  81 # else /* HAVE_NETPACKET_PACKET_H */
  82 /* LynxOS, Linux distributions with older glibc */
  83 # ifdef __Lynx__
  84 /* LynxOS */
  85 #  include <netpacket/if_packet.h>
  86 # else /* __Lynx__ */
  87 /* Linux */
  88 #  include <linux/types.h>
  89 #  include <linux/if_packet.h>
  90 # endif /* __Lynx__ */
  91 # endif /* HAVE_NETPACKET_PACKET_H */
  92 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
  93
  94 /*
  95  * This is fun.
  96  *
  97  * In older BSD systems, socket addresses were fixed-length, and
  98  * "sizeof (struct sockaddr)" gave the size of the structure.
  99  * All addresses fit within a "struct sockaddr".
 100  *
 101  * In newer BSD systems, the socket address is variable-length, and
 102  * there's an "sa_len" field giving the length of the structure;
 103  * this allows socket addresses to be longer than 2 bytes of family
 104  * and 14 bytes of data.
 105  *
 106  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
 107  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
 108  * than "struct sockaddr"), and some use the new BSD scheme.
 109  *
 110  * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
 111  * macro that determines the size based on the address family.  Other
 112  * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
 113  * but not in the final version).  On the latter systems, we explicitly
 114  * check the AF_ type to determine the length; we assume that on
 115  * all those systems we have "struct sockaddr_storage".
 116  */
 117 #ifndef SA_LEN
 118 #ifdef HAVE_SOCKADDR_SA_LEN
 119 #define SA_LEN(addr)    ((addr)->sa_len)
 120 #else /* HAVE_SOCKADDR_SA_LEN */
 121 #ifdef HAVE_SOCKADDR_STORAGE
 122 static size_t
 123 get_sa_len(struct sockaddr *addr)
 124 {
 125         switch (addr->sa_family) {
 126
 127 #ifdef AF_INET
 128         case AF_INET:
 129                 return (sizeof (struct sockaddr_in));
 130 #endif
 131
 132 #ifdef AF_INET6
 133         case AF_INET6:
 134                 return (sizeof (struct sockaddr_in6));
 135 #endif
 136
 137 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
 138         case AF_PACKET:
 139                 return (sizeof (struct sockaddr_ll));
 140 #endif
 141
 142         default:
 143                 return (sizeof (struct sockaddr));
 144         }
 145 }
 146 #define SA_LEN(addr)    (get_sa_len(addr))
 147 #else /* HAVE_SOCKADDR_STORAGE */
 148 #define SA_LEN(addr)    (sizeof (struct sockaddr))
 149 #endif /* HAVE_SOCKADDR_STORAGE */
 150 #endif /* HAVE_SOCKADDR_SA_LEN */
 151 #endif /* SA_LEN */
 152
 153 /*
 154  * Get a list of all interfaces that are up and that we can open.
 155  * Returns -1 on error, 0 otherwise.
 156  * The list, as returned through "alldevsp", may be null if no interfaces
 157  * could be opened.
 158  */
 159 int
 160 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf,
 161     int (*check_usable)(const char *))
 162 {
 163         pcap_if_t *devlist = NULL;
 164         struct ifaddrs *ifap, *ifa;
 165         struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
 166         size_t addr_size, broadaddr_size, dstaddr_size;
 167         int ret = 0;
 168         char *p, *q;
 169
 170         /*
 171          * Get the list of interface addresses.
 172          *
 173          * Note: this won't return information about interfaces
 174          * with no addresses, so, if a platform has interfaces
 175          * with no interfaces on which traffic can be captured,
 176          * we must check for those interfaces as well (see, for
 177          * example, what's done on Linux).
 178          *
 179          * LAN interfaces will probably have link-layer
 180          * addresses; I don't know whether all implementations
 181          * of "getifaddrs()" now, or in the future, will return
 182          * those.
 183          */
 184         if (getifaddrs(&ifap) != 0) {
 185                 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 186                     "getifaddrs: %s", pcap_strerror(errno));
 187                 return (-1);
 188         }
 189         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 190                 /*
 191                  * If this entry has a colon followed by a number at
 192                  * the end, we assume it's a logical interface.  Those
 193                  * are just the way you assign multiple IP addresses to
 194                  * a real interface on Linux, so an entry for a logical
 195                  * interface should be treated like the entry for the
 196                  * real interface; we do that by stripping off the ":"
 197                  * and the number.
 198                  *
 199                  * XXX - should we do this only on Linux?
 200                  */
 201                 p = strchr(ifa->ifa_name, ':');
 202                 if (p != NULL) {
 203                         /*
 204                          * We have a ":"; is it followed by a number?
 205                          */
 206                         q = p + 1;
 207                         while (isdigit((unsigned char)*q))
 208                                 q++;
 209                         if (*q == '\0') {
 210                                 /*
 211                                  * All digits after the ":" until the end.
 212                                  * Strip off the ":" and everything after
 213                                  * it.
 214                                  */
 215                                *p = '\0';
 216                         }
 217                 }
 218
 219                 /*
 220                  * Can we capture on this device?
 221                  */
 222                 if (!(*check_usable)(ifa->ifa_name)) {
 223                         /*
 224                          * No.
 225                          */
 226                         continue;
 227                 }
 228
 229                 /*
 230                  * "ifa_addr" was apparently null on at least one
 231                  * interface on some system.  Therefore, we supply
 232                  * the address and netmask only if "ifa_addr" is
 233                  * non-null (if there's no address, there's obviously
 234                  * no netmask).
 235                  */
 236                 if (ifa->ifa_addr != NULL) {
 237                         addr = ifa->ifa_addr;
 238                         addr_size = SA_LEN(addr);
 239                         netmask = ifa->ifa_netmask;
 240                 } else {
 241                         addr = NULL;
 242                         addr_size = 0;
 243                         netmask = NULL;
 244                 }
 245
 246                 /*
 247                  * Note that, on some platforms, ifa_broadaddr and
 248                  * ifa_dstaddr could be the same field (true on at
 249                  * least some versions of *BSD and OS X), so we
 250                  * can't just check whether the broadcast address
 251                  * is null and add it if so and check whether the
 252                  * destination address is null and add it if so.
 253                  *
 254                  * Therefore, we must also check the IFF_BROADCAST
 255                  * flag, and only add a broadcast address if it's
 256                  * set, and check the IFF_POINTTOPOINT flag, and
 257                  * only add a destination address if it's set (as
 258                  * per man page recommendations on some of those
 259                  * platforms).
 260                  */
 261                 if (ifa->ifa_flags & IFF_BROADCAST &&
 262                     ifa->ifa_broadaddr != NULL) {
 263                         broadaddr = ifa->ifa_broadaddr;
 264                         broadaddr_size = SA_LEN(broadaddr);
 265                 } else {
 266                         broadaddr = NULL;
 267                         broadaddr_size = 0;
 268                 }
 269                 if (ifa->ifa_flags & IFF_POINTOPOINT &&
 270                     ifa->ifa_dstaddr != NULL) {
 271                         dstaddr = ifa->ifa_dstaddr;
 272                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 273                 } else {
 274                         dstaddr = NULL;
 275                         dstaddr_size = 0;
 276                 }
 277
 278                 /*
 279                  * Add information for this address to the list.
 280                  */
 281                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 282                     if_flags_to_pcap_flags(ifa->ifa_name, ifa->ifa_flags),
 283                     addr, addr_size, netmask, addr_size,
 284                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 285                     errbuf) < 0) {
 286                         ret = -1;
 287                         break;
 288                 }
 289         }
 290
 291         freeifaddrs(ifap);
 292
 293         if (ret == -1) {
 294                 /*
 295                  * We had an error; free the list we've been constructing.
 296                  */
 297                 if (devlist != NULL) {
 298                         pcap_freealldevs(devlist);
 299                         devlist = NULL;
 300                 }
 301         }
 302
 303         *alldevsp = devlist;
 304         return (ret);
 305 }