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 1.12 2007-09-14 00:44:55 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 <ctype.h> 51 #include <errno.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <ifaddrs.h> 56 57 #include "pcap-int.h" 58 59 #ifdef HAVE_OS_PROTO_H 60 #include "os-proto.h" 61 #endif 62 63 #ifdef AF_PACKET 64 # ifdef __Lynx__ 65 /* LynxOS */ 66 # include <netpacket/if_packet.h> 67 # else 68 /* Linux */ 69 # include <linux/types.h> 70 # include <linux/if_packet.h> 71 # endif 72 #endif 73 74 /* 75 * This is fun. 76 * 77 * In older BSD systems, socket addresses were fixed-length, and 78 * "sizeof (struct sockaddr)" gave the size of the structure. 79 * All addresses fit within a "struct sockaddr". 80 * 81 * In newer BSD systems, the socket address is variable-length, and 82 * there's an "sa_len" field giving the length of the structure; 83 * this allows socket addresses to be longer than 2 bytes of family 84 * and 14 bytes of data. 85 * 86 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 87 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 88 * than "struct sockaddr"), and some use the new BSD scheme. 89 * 90 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 91 * macro that determines the size based on the address family. Other 92 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 93 * but not in the final version). On the latter systems, we explicitly 94 * check the AF_ type to determine the length; we assume that on 95 * all those systems we have "struct sockaddr_storage". 96 */ 97 #ifndef SA_LEN 98 #ifdef HAVE_SOCKADDR_SA_LEN 99 #define SA_LEN(addr) ((addr)->sa_len) 100 #else /* HAVE_SOCKADDR_SA_LEN */ 101 #ifdef HAVE_SOCKADDR_STORAGE 102 static size_t 103 get_sa_len(struct sockaddr *addr) 104 { 105 switch (addr->sa_family) { 106 107 #ifdef AF_INET 108 case AF_INET: 109 return (sizeof (struct sockaddr_in)); 110 #endif 111 112 #ifdef AF_INET6 113 case AF_INET6: 114 return (sizeof (struct sockaddr_in6)); 115 #endif 116 117 #ifdef AF_PACKET 118 case AF_PACKET: 119 return (sizeof (struct sockaddr_ll)); 120 #endif 121 122 default: 123 return (sizeof (struct sockaddr)); 124 } 125 } 126 #define SA_LEN(addr) (get_sa_len(addr)) 127 #else /* HAVE_SOCKADDR_STORAGE */ 128 #define SA_LEN(addr) (sizeof (struct sockaddr)) 129 #endif /* HAVE_SOCKADDR_STORAGE */ 130 #endif /* HAVE_SOCKADDR_SA_LEN */ 131 #endif /* SA_LEN */ 132 133 /* 134 * Get a list of all interfaces that are up and that we can open. 135 * Returns -1 on error, 0 otherwise. 136 * The list, as returned through "alldevsp", may be null if no interfaces 137 * were up and could be opened. 138 * 139 * This is the implementation used on platforms that have "getifaddrs()". 140 */ 141 int 142 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 143 { 144 pcap_if_t *devlist = NULL; 145 struct ifaddrs *ifap, *ifa; 146 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 147 size_t addr_size, broadaddr_size, dstaddr_size; 148 int ret = 0; 149 char *p, *q; 150 151 /* 152 * Get the list of interface addresses. 153 * 154 * Note: this won't return information about interfaces 155 * with no addresses; are there any such interfaces 156 * that would be capable of receiving packets? 157 * (Interfaces incapable of receiving packets aren't 158 * very interesting from libpcap's point of view.) 159 * 160 * LAN interfaces will probably have link-layer 161 * addresses; I don't know whether all implementations 162 * of "getifaddrs()" now, or in the future, will return 163 * those. 164 */ 165 if (getifaddrs(&ifap) != 0) { 166 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 167 "getifaddrs: %s", pcap_strerror(errno)); 168 return (-1); 169 } 170 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 171 /* 172 * Is this interface up? 173 */ 174 if (!(ifa->ifa_flags & IFF_UP)) { 175 /* 176 * No, so don't add it to the list. 177 */ 178 continue; 179 } 180 181 /* 182 * "ifa_addr" was apparently null on at least one 183 * interface on some system. 184 * 185 * "ifa_broadaddr" may be non-null even on 186 * non-broadcast interfaces, and was null on 187 * at least one OpenBSD 3.4 system on at least 188 * one interface with IFF_BROADCAST set. 189 * 190 * "ifa_dstaddr" was, on at least one FreeBSD 4.1 191 * system, non-null on a non-point-to-point 192 * interface. 193 * 194 * Therefore, we supply the address and netmask only 195 * if "ifa_addr" is non-null (if there's no address, 196 * there's obviously no netmask), and supply the 197 * broadcast and destination addresses if the appropriate 198 * flag is set *and* the appropriate "ifa_" entry doesn't 199 * evaluate to a null pointer. 200 */ 201 if (ifa->ifa_addr != NULL) { 202 addr = ifa->ifa_addr; 203 addr_size = SA_LEN(addr); 204 netmask = ifa->ifa_netmask; 205 } else { 206 addr = NULL; 207 addr_size = 0; 208 netmask = NULL; 209 } 210 if (ifa->ifa_flags & IFF_BROADCAST && 211 ifa->ifa_broadaddr != NULL) { 212 broadaddr = ifa->ifa_broadaddr; 213 broadaddr_size = SA_LEN(broadaddr); 214 } else { 215 broadaddr = NULL; 216 broadaddr_size = 0; 217 } 218 if (ifa->ifa_flags & IFF_POINTOPOINT && 219 ifa->ifa_dstaddr != NULL) { 220 dstaddr = ifa->ifa_dstaddr; 221 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 222 } else { 223 dstaddr = NULL; 224 dstaddr_size = 0; 225 } 226 227 /* 228 * If this entry has a colon followed by a number at 229 * the end, we assume it's a logical interface. Those 230 * are just the way you assign multiple IP addresses to 231 * a real interface on Linux, so an entry for a logical 232 * interface should be treated like the entry for the 233 * real interface; we do that by stripping off the ":" 234 * and the number. 235 * 236 * XXX - should we do this only on Linux? 237 */ 238 p = strchr(ifa->ifa_name, ':'); 239 if (p != NULL) { 240 /* 241 * We have a ":"; is it followed by a number? 242 */ 243 q = p + 1; 244 while (isdigit((unsigned char)*q)) 245 q++; 246 if (*q == '\0') { 247 /* 248 * All digits after the ":" until the end. 249 * Strip off the ":" and everything after 250 * it. 251 */ 252 *p = '\0'; 253 } 254 } 255 256 /* 257 * Add information for this address to the list. 258 */ 259 if (add_addr_to_iflist(&devlist, ifa->ifa_name, 260 ifa->ifa_flags, addr, addr_size, netmask, addr_size, 261 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 262 errbuf) < 0) { 263 ret = -1; 264 break; 265 } 266 } 267 268 freeifaddrs(ifap); 269 270 if (ret != -1) { 271 /* 272 * We haven't had any errors yet; do any platform-specific 273 * operations to add devices. 274 */ 275 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 276 ret = -1; 277 } 278 279 if (ret == -1) { 280 /* 281 * We had an error; free the list we've been constructing. 282 */ 283 if (devlist != NULL) { 284 pcap_freealldevs(devlist); 285 devlist = NULL; 286 } 287 } 288 289 *alldevsp = devlist; 290 return (ret); 291 } 292