fad-getad.c revision 147894
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 36static const char rcsid[] _U_ = 37 "@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.10.2.1 2005/04/10 18:04:49 hannes 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# include <linux/if_packet.h> 65#endif 66 67/* 68 * This is fun. 69 * 70 * In older BSD systems, socket addresses were fixed-length, and 71 * "sizeof (struct sockaddr)" gave the size of the structure. 72 * All addresses fit within a "struct sockaddr". 73 * 74 * In newer BSD systems, the socket address is variable-length, and 75 * there's an "sa_len" field giving the length of the structure; 76 * this allows socket addresses to be longer than 2 bytes of family 77 * and 14 bytes of data. 78 * 79 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 80 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 81 * than "struct sockaddr"), and some use the new BSD scheme. 82 * 83 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 84 * macro that determines the size based on the address family. Other 85 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 86 * but not in the final version). On the latter systems, we explicitly 87 * check the AF_ type to determine the length; we assume that on 88 * all those systems we have "struct sockaddr_storage". 89 */ 90#ifndef SA_LEN 91#ifdef HAVE_SOCKADDR_SA_LEN 92#define SA_LEN(addr) ((addr)->sa_len) 93#else /* HAVE_SOCKADDR_SA_LEN */ 94#ifdef HAVE_SOCKADDR_STORAGE 95static size_t 96get_sa_len(struct sockaddr *addr) 97{ 98 switch (addr->sa_family) { 99 100#ifdef AF_INET 101 case AF_INET: 102 return (sizeof (struct sockaddr_in)); 103#endif 104 105#ifdef AF_INET6 106 case AF_INET6: 107 return (sizeof (struct sockaddr_in6)); 108#endif 109 110#ifdef AF_PACKET 111 case AF_PACKET: 112 return (sizeof (struct sockaddr_ll)); 113#endif 114 115 default: 116 return (sizeof (struct sockaddr)); 117 } 118} 119#define SA_LEN(addr) (get_sa_len(addr)) 120#else /* HAVE_SOCKADDR_STORAGE */ 121#define SA_LEN(addr) (sizeof (struct sockaddr)) 122#endif /* HAVE_SOCKADDR_STORAGE */ 123#endif /* HAVE_SOCKADDR_SA_LEN */ 124#endif /* SA_LEN */ 125 126/* 127 * Get a list of all interfaces that are up and that we can open. 128 * Returns -1 on error, 0 otherwise. 129 * The list, as returned through "alldevsp", may be null if no interfaces 130 * were up and could be opened. 131 * 132 * This is the implementation used on platforms that have "getifaddrs()". 133 */ 134int 135pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 136{ 137 pcap_if_t *devlist = NULL; 138 struct ifaddrs *ifap, *ifa; 139 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 140 size_t addr_size, broadaddr_size, dstaddr_size; 141 int ret = 0; 142 char *p, *q; 143 144 /* 145 * Get the list of interface addresses. 146 * 147 * Note: this won't return information about interfaces 148 * with no addresses; are there any such interfaces 149 * that would be capable of receiving packets? 150 * (Interfaces incapable of receiving packets aren't 151 * very interesting from libpcap's point of view.) 152 * 153 * LAN interfaces will probably have link-layer 154 * addresses; I don't know whether all implementations 155 * of "getifaddrs()" now, or in the future, will return 156 * those. 157 */ 158 if (getifaddrs(&ifap) != 0) { 159 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 160 "getifaddrs: %s", pcap_strerror(errno)); 161 return (-1); 162 } 163 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 164 /* 165 * Is this interface up? 166 */ 167 if (!(ifa->ifa_flags & IFF_UP)) { 168 /* 169 * No, so don't add it to the list. 170 */ 171 continue; 172 } 173 174 /* 175 * "ifa_addr" was apparently null on at least one 176 * interface on some system. 177 * 178 * "ifa_broadaddr" may be non-null even on 179 * non-broadcast interfaces, and was null on 180 * at least one OpenBSD 3.4 system on at least 181 * one interface with IFF_BROADCAST set. 182 * 183 * "ifa_dstaddr" was, on at least one FreeBSD 4.1 184 * system, non-null on a non-point-to-point 185 * interface. 186 * 187 * Therefore, we supply the address and netmask only 188 * if "ifa_addr" is non-null (if there's no address, 189 * there's obviously no netmask), and supply the 190 * broadcast and destination addresses if the appropriate 191 * flag is set *and* the appropriate "ifa_" entry doesn't 192 * evaluate to a null pointer. 193 */ 194 if (ifa->ifa_addr != NULL) { 195 addr = ifa->ifa_addr; 196 addr_size = SA_LEN(addr); 197 netmask = ifa->ifa_netmask; 198 } else { 199 addr = NULL; 200 addr_size = 0; 201 netmask = NULL; 202 } 203 if (ifa->ifa_flags & IFF_BROADCAST && 204 ifa->ifa_broadaddr != NULL) { 205 broadaddr = ifa->ifa_broadaddr; 206 broadaddr_size = SA_LEN(broadaddr); 207 } else { 208 broadaddr = NULL; 209 broadaddr_size = 0; 210 } 211 if (ifa->ifa_flags & IFF_POINTOPOINT && 212 ifa->ifa_dstaddr != NULL) { 213 dstaddr = ifa->ifa_dstaddr; 214 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 215 } else { 216 dstaddr = NULL; 217 dstaddr_size = 0; 218 } 219 220 /* 221 * If this entry has a colon followed by a number at 222 * the end, we assume it's a logical interface. Those 223 * are just the way you assign multiple IP addresses to 224 * a real interface on Linux, so an entry for a logical 225 * interface should be treated like the entry for the 226 * real interface; we do that by stripping off the ":" 227 * and the number. 228 * 229 * XXX - should we do this only on Linux? 230 */ 231 p = strchr(ifa->ifa_name, ':'); 232 if (p != NULL) { 233 /* 234 * We have a ":"; is it followed by a number? 235 */ 236 q = p + 1; 237 while (isdigit((unsigned char)*q)) 238 q++; 239 if (*q == '\0') { 240 /* 241 * All digits after the ":" until the end. 242 * Strip off the ":" and everything after 243 * it. 244 */ 245 *p = '\0'; 246 } 247 } 248 249 /* 250 * Add information for this address to the list. 251 */ 252 if (add_addr_to_iflist(&devlist, ifa->ifa_name, 253 ifa->ifa_flags, addr, addr_size, netmask, addr_size, 254 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 255 errbuf) < 0) { 256 ret = -1; 257 break; 258 } 259 } 260 261 freeifaddrs(ifap); 262 263 if (ret != -1) { 264 /* 265 * We haven't had any errors yet; do any platform-specific 266 * operations to add devices. 267 */ 268 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 269 ret = -1; 270 } 271 272 if (ret == -1) { 273 /* 274 * We had an error; free the list we've been constructing. 275 */ 276 if (devlist != NULL) { 277 pcap_freealldevs(devlist); 278 devlist = NULL; 279 } 280 } 281 282 *alldevsp = devlist; 283 return (ret); 284} 285