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 #ifndef lint
  36 static const char rcsid[] =
  37     "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.3 2002-08-26 09:50:45 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include <sys/types.h>
  45 #include <sys/socket.h>
  46
  47 #include <net/if.h>
  48
  49 #include <errno.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <ifaddrs.h>
  53
  54 #include "pcap-int.h"
  55
  56 #ifdef HAVE_OS_PROTO_H
  57 #include "os-proto.h"
  58 #endif
  59
  60 /*
  61  * This is fun.
  62  *
  63  * In older BSD systems, socket addresses were fixed-length, and
  64  * "sizeof (struct sockaddr)" gave the size of the structure.
  65  * All addresses fit within a "struct sockaddr".
  66  *
  67  * In newer BSD systems, the socket address is variable-length, and
  68  * there's an "sa_len" field giving the length of the structure;
  69  * this allows socket addresses to be longer than 2 bytes of family
  70  * and 14 bytes of data.
  71  *
  72  * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
  73  * variant of the old BSD scheme (with "struct sockaddr_storage" rather
  74  * than "struct sockaddr"), and some use the new BSD scheme.
  75  *
  76  * GNU libc uses neither scheme, but has an "SA_LEN()" macro that
  77  * determines the size based on the address family.
  78  */
  79 #ifndef SA_LEN
  80 #ifdef HAVE_SOCKADDR_SA_LEN
  81 #define SA_LEN(addr)    ((addr)->sa_len)
  82 #else /* HAVE_SOCKADDR_SA_LEN */
  83 #ifdef HAVE_SOCKADDR_STORAGE
  84 #define SA_LEN(addr)    (sizeof (struct sockaddr_storage))
  85 #else /* HAVE_SOCKADDR_STORAGE */
  86 #define SA_LEN(addr)    (sizeof (struct sockaddr))
  87 #endif /* HAVE_SOCKADDR_STORAGE */
  88 #endif /* HAVE_SOCKADDR_SA_LEN */
  89 #endif /* SA_LEN */
  90
  91 /*
  92  * Get a list of all interfaces that are up and that we can open.
  93  * Returns -1 on error, 0 otherwise.
  94  * The list, as returned through "alldevsp", may be null if no interfaces
  95  * were up and could be opened.
  96  *
  97  * This is the implementation used on platforms that have "getifaddrs()".
  98  */
  99 int
 100 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
 101 {
 102         pcap_if_t *devlist = NULL;
 103         struct ifaddrs *ifap, *ifa;
 104         struct sockaddr *broadaddr, *dstaddr;
 105         size_t broadaddr_size, dstaddr_size;
 106         int ret = 0;
 107
 108         /*
 109          * Get the list of interface addresses.
 110          *
 111          * Note: this won't return information about interfaces
 112          * with no addresses; are there any such interfaces
 113          * that would be capable of receiving packets?
 114          * (Interfaces incapable of receiving packets aren't
 115          * very interesting from libpcap's point of view.)
 116          *
 117          * LAN interfaces will probably have link-layer
 118          * addresses; I don't know whether all implementations
 119          * of "getifaddrs()" now, or in the future, will return
 120          * those.
 121          */
 122         if (getifaddrs(&ifap) != 0) {
 123                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 124                     "getifaddrs: %s", pcap_strerror(errno));
 125                 return (-1);
 126         }
 127         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
 128                 /*
 129                  * Is this interface up?
 130                  */
 131                 if (!(ifa->ifa_flags & IFF_UP)) {
 132                         /*
 133                          * No, so don't add it to the list.
 134                          */
 135                         continue;
 136                 }
 137
 138                 /*
 139                  * "ifa_broadaddr" may be non-null even on
 140                  * non-broadcast interfaces; "ifa_dstaddr"
 141                  * was, on at least one FreeBSD 4.1 system,
 142                  * non-null on a non-point-to-point
 143                  * interface.
 144                  */
 145                 if (ifa->ifa_flags & IFF_BROADCAST) {
 146                         broadaddr = ifa->ifa_broadaddr;
 147                         broadaddr_size = SA_LEN(broadaddr);
 148                 } else {
 149                         broadaddr = NULL;
 150                         broadaddr_size = 0;
 151                 }
 152                 if (ifa->ifa_flags & IFF_POINTOPOINT) {
 153                         dstaddr = ifa->ifa_dstaddr;
 154                         dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
 155                 } else {
 156                         dstaddr = NULL;
 157                         dstaddr_size = 0;
 158                 }
 159
 160                 /*
 161                  * Add information for this address to the list.
 162                  */
 163                 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
 164                     ifa->ifa_flags, ifa->ifa_addr, SA_LEN(ifa->ifa_addr),
 165                     ifa->ifa_netmask, SA_LEN(ifa->ifa_netmask),
 166                     broadaddr, broadaddr_size, dstaddr, dstaddr_size,
 167                     errbuf) < 0) {
 168                         ret = -1;
 169                         break;
 170                 }
 171         }
 172
 173         freeifaddrs(ifap);
 174
 175         if (ret != -1) {
 176                 /*
 177                  * We haven't had any errors yet; do any platform-specific
 178                  * operations to add devices.
 179                  */
 180                 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
 181                         ret = -1;
 182         }
 183
 184         if (ret == -1) {
 185                 /*
 186                  * We had an error; free the list we've been constructing.
 187                  */
 188                 if (devlist != NULL) {
 189                         pcap_freealldevs(devlist);
 190                         devlist = NULL;
 191                 }
 192         }
 193
 194         *alldevsp = devlist;
 195         return (ret);
 196 }