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[] _U_ = 37 "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.7.2.2 2004/03/11 23:04:52 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 #include <netinet/in.h> 47 48 #include <net/if.h> 49 50 #include <errno.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <ifaddrs.h> 54 55 #include "pcap-int.h" 56 57 #ifdef HAVE_OS_PROTO_H 58 #include "os-proto.h" 59 #endif 60 61 /* 62 * This is fun. 63 * 64 * In older BSD systems, socket addresses were fixed-length, and 65 * "sizeof (struct sockaddr)" gave the size of the structure. 66 * All addresses fit within a "struct sockaddr". 67 * 68 * In newer BSD systems, the socket address is variable-length, and 69 * there's an "sa_len" field giving the length of the structure; 70 * this allows socket addresses to be longer than 2 bytes of family 71 * and 14 bytes of data. 72 * 73 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 74 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 75 * than "struct sockaddr"), and some use the new BSD scheme. 76 * 77 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 78 * macro that determines the size based on the address family. Other 79 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 80 * but not in the final version). On the latter systems, we explicitly 81 * check the AF_ type to determine the length; we assume that on 82 * all those systems we have "struct sockaddr_storage". 83 */ 84 #ifndef SA_LEN 85 #ifdef HAVE_SOCKADDR_SA_LEN 86 #define SA_LEN(addr) ((addr)->sa_len) 87 #else /* HAVE_SOCKADDR_SA_LEN */ 88 #ifdef HAVE_SOCKADDR_STORAGE 89 static size_t 90 get_sa_len(struct sockaddr *addr) 91 { 92 switch (addr->sa_family) { 93 94 #ifdef AF_INET 95 case AF_INET: 96 return (sizeof (struct sockaddr_in)); 97 #endif 98 99 #ifdef AF_INET6 100 case AF_INET6: 101 return (sizeof (struct sockaddr_in6)); 102 #endif 103 104 default: 105 return (sizeof (struct sockaddr)); 106 } 107 } 108 #define SA_LEN(addr) (get_sa_len(addr)) 109 #else /* HAVE_SOCKADDR_STORAGE */ 110 #define SA_LEN(addr) (sizeof (struct sockaddr)) 111 #endif /* HAVE_SOCKADDR_STORAGE */ 112 #endif /* HAVE_SOCKADDR_SA_LEN */ 113 #endif /* SA_LEN */ 114 115 /* 116 * Get a list of all interfaces that are up and that we can open. 117 * Returns -1 on error, 0 otherwise. 118 * The list, as returned through "alldevsp", may be null if no interfaces 119 * were up and could be opened. 120 * 121 * This is the implementation used on platforms that have "getifaddrs()". 122 */ 123 int 124 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 125 { 126 pcap_if_t *devlist = NULL; 127 struct ifaddrs *ifap, *ifa; 128 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 129 size_t addr_size, broadaddr_size, dstaddr_size; 130 int ret = 0; 131 132 /* 133 * Get the list of interface addresses. 134 * 135 * Note: this won't return information about interfaces 136 * with no addresses; are there any such interfaces 137 * that would be capable of receiving packets? 138 * (Interfaces incapable of receiving packets aren't 139 * very interesting from libpcap's point of view.) 140 * 141 * LAN interfaces will probably have link-layer 142 * addresses; I don't know whether all implementations 143 * of "getifaddrs()" now, or in the future, will return 144 * those. 145 */ 146 if (getifaddrs(&ifap) != 0) { 147 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 148 "getifaddrs: %s", pcap_strerror(errno)); 149 return (-1); 150 } 151 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 152 /* 153 * Is this interface up? 154 */ 155 if (!(ifa->ifa_flags & IFF_UP)) { 156 /* 157 * No, so don't add it to the list. 158 */ 159 continue; 160 } 161 162 /* 163 * "ifa_addr" was apparently null on at least one 164 * interface on some system. 165 * 166 * "ifa_broadaddr" may be non-null even on 167 * non-broadcast interfaces, and was null on 168 * at least one OpenBSD 3.4 system on at least 169 * one interface with IFF_BROADCAST set. 170 * 171 * "ifa_dstaddr" was, on at least one FreeBSD 4.1 172 * system, non-null on a non-point-to-point 173 * interface. 174 * 175 * Therefore, we supply the address and netmask only 176 * if "ifa_addr" is non-null (if there's no address, 177 * there's obviously no netmask), and supply the 178 * broadcast and destination addresses if the appropriate 179 * flag is set *and* the appropriate "ifa_" entry doesn't 180 * evaluate to a null pointer. 181 */ 182 if (ifa->ifa_addr != NULL) { 183 addr = ifa->ifa_addr; 184 addr_size = SA_LEN(addr); 185 netmask = ifa->ifa_netmask; 186 } else { 187 addr = NULL; 188 addr_size = 0; 189 netmask = NULL; 190 } 191 if (ifa->ifa_flags & IFF_BROADCAST && 192 ifa->ifa_broadaddr != NULL) { 193 broadaddr = ifa->ifa_broadaddr; 194 broadaddr_size = SA_LEN(broadaddr); 195 } else { 196 broadaddr = NULL; 197 broadaddr_size = 0; 198 } 199 if (ifa->ifa_flags & IFF_POINTOPOINT && 200 ifa->ifa_dstaddr != NULL) { 201 dstaddr = ifa->ifa_dstaddr; 202 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 203 } else { 204 dstaddr = NULL; 205 dstaddr_size = 0; 206 } 207 208 /* 209 * Add information for this address to the list. 210 */ 211 if (add_addr_to_iflist(&devlist, ifa->ifa_name, 212 ifa->ifa_flags, addr, addr_size, netmask, addr_size, 213 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 214 errbuf) < 0) { 215 ret = -1; 216 break; 217 } 218 } 219 220 freeifaddrs(ifap); 221 222 if (ret != -1) { 223 /* 224 * We haven't had any errors yet; do any platform-specific 225 * operations to add devices. 226 */ 227 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 228 ret = -1; 229 } 230 231 if (ret == -1) { 232 /* 233 * We had an error; free the list we've been constructing. 234 */ 235 if (devlist != NULL) { 236 pcap_freealldevs(devlist); 237 devlist = NULL; 238 } 239 } 240 241 *alldevsp = devlist; 242 return (ret); 243 } 244