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 HAVE_NETPACKET_PACKET_H 65 /* Solaris 11 and later, Linux distributions with newer glibc */ 66 # include <netpacket/packet.h> 67 # else /* HAVE_NETPACKET_PACKET_H */ 68 /* LynxOS, Linux distributions with older glibc */ 69 # ifdef __Lynx__ 70 /* LynxOS */ 71 # include <netpacket/if_packet.h> 72 # else /* __Lynx__ */ 73 /* Linux */ 74 # include <linux/types.h> 75 # include <linux/if_packet.h> 76 # endif /* __Lynx__ */ 77 # endif /* HAVE_NETPACKET_PACKET_H */ 78 #endif /* AF_PACKET */ 79 80 /* 81 * This is fun. 82 * 83 * In older BSD systems, socket addresses were fixed-length, and 84 * "sizeof (struct sockaddr)" gave the size of the structure. 85 * All addresses fit within a "struct sockaddr". 86 * 87 * In newer BSD systems, the socket address is variable-length, and 88 * there's an "sa_len" field giving the length of the structure; 89 * this allows socket addresses to be longer than 2 bytes of family 90 * and 14 bytes of data. 91 * 92 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 93 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 94 * than "struct sockaddr"), and some use the new BSD scheme. 95 * 96 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 97 * macro that determines the size based on the address family. Other 98 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 99 * but not in the final version). On the latter systems, we explicitly 100 * check the AF_ type to determine the length; we assume that on 101 * all those systems we have "struct sockaddr_storage". 102 */ 103 #ifndef SA_LEN 104 #ifdef HAVE_SOCKADDR_SA_LEN 105 #define SA_LEN(addr) ((addr)->sa_len) 106 #else /* HAVE_SOCKADDR_SA_LEN */ 107 #ifdef HAVE_SOCKADDR_STORAGE 108 static size_t 109 get_sa_len(struct sockaddr *addr) 110 { 111 switch (addr->sa_family) { 112 113 #ifdef AF_INET 114 case AF_INET: 115 return (sizeof (struct sockaddr_in)); 116 #endif 117 118 #ifdef AF_INET6 119 case AF_INET6: 120 return (sizeof (struct sockaddr_in6)); 121 #endif 122 123 #ifdef AF_PACKET 124 case AF_PACKET: 125 return (sizeof (struct sockaddr_ll)); 126 #endif 127 128 default: 129 return (sizeof (struct sockaddr)); 130 } 131 } 132 #define SA_LEN(addr) (get_sa_len(addr)) 133 #else /* HAVE_SOCKADDR_STORAGE */ 134 #define SA_LEN(addr) (sizeof (struct sockaddr)) 135 #endif /* HAVE_SOCKADDR_STORAGE */ 136 #endif /* HAVE_SOCKADDR_SA_LEN */ 137 #endif /* SA_LEN */ 138 139 /* 140 * Get a list of all interfaces that are up and that we can open. 141 * Returns -1 on error, 0 otherwise. 142 * The list, as returned through "alldevsp", may be null if no interfaces 143 * were up and could be opened. 144 * 145 * This is the implementation used on platforms that have "getifaddrs()". 146 */ 147 int 148 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 149 { 150 pcap_if_t *devlist = NULL; 151 struct ifaddrs *ifap, *ifa; 152 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 153 size_t addr_size, broadaddr_size, dstaddr_size; 154 int ret = 0; 155 char *p, *q; 156 157 /* 158 * Get the list of interface addresses. 159 * 160 * Note: this won't return information about interfaces 161 * with no addresses; are there any such interfaces 162 * that would be capable of receiving packets? 163 * (Interfaces incapable of receiving packets aren't 164 * very interesting from libpcap's point of view.) 165 * 166 * LAN interfaces will probably have link-layer 167 * addresses; I don't know whether all implementations 168 * of "getifaddrs()" now, or in the future, will return 169 * those. 170 */ 171 if (getifaddrs(&ifap) != 0) { 172 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 173 "getifaddrs: %s", pcap_strerror(errno)); 174 return (-1); 175 } 176 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 177 /* 178 * Is this interface up? 179 */ 180 if (!(ifa->ifa_flags & IFF_UP)) { 181 /* 182 * No, so don't add it to the list. 183 */ 184 continue; 185 } 186 187 /* 188 * "ifa_addr" was apparently null on at least one 189 * interface on some system. 190 * 191 * "ifa_broadaddr" may be non-null even on 192 * non-broadcast interfaces, and was null on 193 * at least one OpenBSD 3.4 system on at least 194 * one interface with IFF_BROADCAST set. 195 * 196 * "ifa_dstaddr" was, on at least one FreeBSD 4.1 197 * system, non-null on a non-point-to-point 198 * interface. 199 * 200 * Therefore, we supply the address and netmask only 201 * if "ifa_addr" is non-null (if there's no address, 202 * there's obviously no netmask), and supply the 203 * broadcast and destination addresses if the appropriate 204 * flag is set *and* the appropriate "ifa_" entry doesn't 205 * evaluate to a null pointer. 206 */ 207 if (ifa->ifa_addr != NULL) { 208 addr = ifa->ifa_addr; 209 addr_size = SA_LEN(addr); 210 netmask = ifa->ifa_netmask; 211 } else { 212 addr = NULL; 213 addr_size = 0; 214 netmask = NULL; 215 } 216 if (ifa->ifa_flags & IFF_BROADCAST && 217 ifa->ifa_broadaddr != NULL) { 218 broadaddr = ifa->ifa_broadaddr; 219 broadaddr_size = SA_LEN(broadaddr); 220 } else { 221 broadaddr = NULL; 222 broadaddr_size = 0; 223 } 224 if (ifa->ifa_flags & IFF_POINTOPOINT && 225 ifa->ifa_dstaddr != NULL) { 226 dstaddr = ifa->ifa_dstaddr; 227 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 228 } else { 229 dstaddr = NULL; 230 dstaddr_size = 0; 231 } 232 233 /* 234 * If this entry has a colon followed by a number at 235 * the end, we assume it's a logical interface. Those 236 * are just the way you assign multiple IP addresses to 237 * a real interface on Linux, so an entry for a logical 238 * interface should be treated like the entry for the 239 * real interface; we do that by stripping off the ":" 240 * and the number. 241 * 242 * XXX - should we do this only on Linux? 243 */ 244 p = strchr(ifa->ifa_name, ':'); 245 if (p != NULL) { 246 /* 247 * We have a ":"; is it followed by a number? 248 */ 249 q = p + 1; 250 while (isdigit((unsigned char)*q)) 251 q++; 252 if (*q == '\0') { 253 /* 254 * All digits after the ":" until the end. 255 * Strip off the ":" and everything after 256 * it. 257 */ 258 *p = '\0'; 259 } 260 } 261 262 /* 263 * Add information for this address to the list. 264 */ 265 if (add_addr_to_iflist(&devlist, ifa->ifa_name, 266 ifa->ifa_flags, addr, addr_size, netmask, addr_size, 267 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 268 errbuf) < 0) { 269 ret = -1; 270 break; 271 } 272 } 273 274 freeifaddrs(ifap); 275 276 if (ret != -1) { 277 /* 278 * We haven't had any errors yet; do any platform-specific 279 * operations to add devices. 280 */ 281 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 282 ret = -1; 283 } 284 285 if (ret == -1) { 286 /* 287 * We had an error; free the list we've been constructing. 288 */ 289 if (devlist != NULL) { 290 pcap_freealldevs(devlist); 291 devlist = NULL; 292 } 293 } 294 295 *alldevsp = devlist; 296 return (ret); 297 } 298