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 #ifdef HAVE_CONFIG_H 36 #include "config.h" 37 #endif 38 39 #include <sys/types.h> 40 #include <sys/socket.h> 41 #include <netinet/in.h> 42 43 #include <net/if.h> 44 45 #include <ctype.h> 46 #include <errno.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <ifaddrs.h> 51 52 #include "pcap-int.h" 53 54 #ifdef HAVE_OS_PROTO_H 55 #include "os-proto.h" 56 #endif 57 58 /* 59 * We don't do this on Solaris 11 and later, as it appears there aren't 60 * any AF_PACKET addresses on interfaces, so we don't need this, and 61 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>, 62 * and their definitions of some data structures collide. 63 */ 64 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) 65 # ifdef HAVE_NETPACKET_PACKET_H 66 /* Linux distributions with newer glibc */ 67 # include <netpacket/packet.h> 68 # else /* HAVE_NETPACKET_PACKET_H */ 69 /* LynxOS, Linux distributions with older glibc */ 70 # ifdef __Lynx__ 71 /* LynxOS */ 72 # include <netpacket/if_packet.h> 73 # else /* __Lynx__ */ 74 /* Linux */ 75 # include <linux/types.h> 76 # include <linux/if_packet.h> 77 # endif /* __Lynx__ */ 78 # endif /* HAVE_NETPACKET_PACKET_H */ 79 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */ 80 81 /* 82 * This is fun. 83 * 84 * In older BSD systems, socket addresses were fixed-length, and 85 * "sizeof (struct sockaddr)" gave the size of the structure. 86 * All addresses fit within a "struct sockaddr". 87 * 88 * In newer BSD systems, the socket address is variable-length, and 89 * there's an "sa_len" field giving the length of the structure; 90 * this allows socket addresses to be longer than 2 bytes of family 91 * and 14 bytes of data. 92 * 93 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 94 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 95 * than "struct sockaddr"), and some use the new BSD scheme. 96 * 97 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 98 * macro that determines the size based on the address family. Other 99 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 100 * but not in the final version). On the latter systems, we explicitly 101 * check the AF_ type to determine the length; we assume that on 102 * all those systems we have "struct sockaddr_storage". 103 */ 104 #ifndef SA_LEN 105 #ifdef HAVE_SOCKADDR_SA_LEN 106 #define SA_LEN(addr) ((addr)->sa_len) 107 #else /* HAVE_SOCKADDR_SA_LEN */ 108 #ifdef HAVE_SOCKADDR_STORAGE 109 static size_t 110 get_sa_len(struct sockaddr *addr) 111 { 112 switch (addr->sa_family) { 113 114 #ifdef AF_INET 115 case AF_INET: 116 return (sizeof (struct sockaddr_in)); 117 #endif 118 119 #ifdef AF_INET6 120 case AF_INET6: 121 return (sizeof (struct sockaddr_in6)); 122 #endif 123 124 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) 125 case AF_PACKET: 126 return (sizeof (struct sockaddr_ll)); 127 #endif 128 129 default: 130 return (sizeof (struct sockaddr)); 131 } 132 } 133 #define SA_LEN(addr) (get_sa_len(addr)) 134 #else /* HAVE_SOCKADDR_STORAGE */ 135 #define SA_LEN(addr) (sizeof (struct sockaddr)) 136 #endif /* HAVE_SOCKADDR_STORAGE */ 137 #endif /* HAVE_SOCKADDR_SA_LEN */ 138 #endif /* SA_LEN */ 139 140 /* 141 * Get a list of all interfaces that are up and that we can open. 142 * Returns -1 on error, 0 otherwise. 143 * The list, as returned through "alldevsp", may be null if no interfaces 144 * could be opened. 145 */ 146 int 147 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf, 148 int (*check_usable)(const char *)) 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, so, if a platform has interfaces 162 * with no interfaces on which traffic can be captured, 163 * we must check for those interfaces as well (see, for 164 * example, what's done on Linux). 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)pcap_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 * If this entry has a colon followed by a number at 179 * the end, we assume it's a logical interface. Those 180 * are just the way you assign multiple IP addresses to 181 * a real interface on Linux, so an entry for a logical 182 * interface should be treated like the entry for the 183 * real interface; we do that by stripping off the ":" 184 * and the number. 185 * 186 * XXX - should we do this only on Linux? 187 */ 188 p = strchr(ifa->ifa_name, ':'); 189 if (p != NULL) { 190 /* 191 * We have a ":"; is it followed by a number? 192 */ 193 q = p + 1; 194 while (isdigit((unsigned char)*q)) 195 q++; 196 if (*q == '\0') { 197 /* 198 * All digits after the ":" until the end. 199 * Strip off the ":" and everything after 200 * it. 201 */ 202 *p = '\0'; 203 } 204 } 205 206 /* 207 * Can we capture on this device? 208 */ 209 if (!(*check_usable)(ifa->ifa_name)) { 210 /* 211 * No. 212 */ 213 continue; 214 } 215 216 /* 217 * "ifa_addr" was apparently null on at least one 218 * interface on some system. Therefore, we supply 219 * the address and netmask only if "ifa_addr" is 220 * non-null (if there's no address, there's obviously 221 * no netmask). 222 */ 223 if (ifa->ifa_addr != NULL) { 224 addr = ifa->ifa_addr; 225 addr_size = SA_LEN(addr); 226 netmask = ifa->ifa_netmask; 227 } else { 228 addr = NULL; 229 addr_size = 0; 230 netmask = NULL; 231 } 232 233 /* 234 * Note that, on some platforms, ifa_broadaddr and 235 * ifa_dstaddr could be the same field (true on at 236 * least some versions of *BSD and OS X), so we 237 * can't just check whether the broadcast address 238 * is null and add it if so and check whether the 239 * destination address is null and add it if so. 240 * 241 * Therefore, we must also check the IFF_BROADCAST 242 * flag, and only add a broadcast address if it's 243 * set, and check the IFF_POINTTOPOINT flag, and 244 * only add a destination address if it's set (as 245 * per man page recommendations on some of those 246 * platforms). 247 */ 248 if (ifa->ifa_flags & IFF_BROADCAST && 249 ifa->ifa_broadaddr != NULL) { 250 broadaddr = ifa->ifa_broadaddr; 251 broadaddr_size = SA_LEN(broadaddr); 252 } else { 253 broadaddr = NULL; 254 broadaddr_size = 0; 255 } 256 if (ifa->ifa_flags & IFF_POINTOPOINT && 257 ifa->ifa_dstaddr != NULL) { 258 dstaddr = ifa->ifa_dstaddr; 259 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 260 } else { 261 dstaddr = NULL; 262 dstaddr_size = 0; 263 } 264 265 /* 266 * Add information for this address to the list. 267 */ 268 if (add_addr_to_iflist(&devlist, ifa->ifa_name, 269 if_flags_to_pcap_flags(ifa->ifa_name, ifa->ifa_flags), 270 addr, addr_size, netmask, addr_size, 271 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 272 errbuf) < 0) { 273 ret = -1; 274 break; 275 } 276 } 277 278 freeifaddrs(ifap); 279 280 if (ret == -1) { 281 /* 282 * We had an error; free the list we've been constructing. 283 */ 284 if (devlist != NULL) { 285 pcap_freealldevs(devlist); 286 devlist = NULL; 287 } 288 } 289 290 *alldevsp = devlist; 291 return (ret); 292 } 293