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