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 <errno.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <ifaddrs.h> 50 51 #include "pcap-int.h" 52 53 #ifdef HAVE_OS_PROTO_H 54 #include "os-proto.h" 55 #endif 56 57 /* 58 * We don't do this on Solaris 11 and later, as it appears there aren't 59 * any AF_PACKET addresses on interfaces, so we don't need this, and 60 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>, 61 * and their definitions of some data structures collide. 62 */ 63 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) 64 # ifdef HAVE_NETPACKET_PACKET_H 65 /* 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 /* (defined(linux) || defined(__Lynx__)) && defined(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_STRUCT_SOCKADDR_SA_LEN 105 #define SA_LEN(addr) ((addr)->sa_len) 106 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 107 #ifdef HAVE_STRUCT_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 #if (defined(linux) || defined(__Lynx__)) && defined(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_STRUCT_SOCKADDR_STORAGE */ 134 #define SA_LEN(addr) (sizeof (struct sockaddr)) 135 #endif /* HAVE_STRUCT_SOCKADDR_STORAGE */ 136 #endif /* HAVE_STRUCT_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 * could be opened. 144 */ 145 int 146 pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, 147 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 148 { 149 struct ifaddrs *ifap, *ifa; 150 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 151 size_t addr_size, broadaddr_size, dstaddr_size; 152 int ret = 0; 153 char *p, *q; 154 155 /* 156 * Get the list of interface addresses. 157 * 158 * Note: this won't return information about interfaces 159 * with no addresses, so, if a platform has interfaces 160 * with no interfaces on which traffic can be captured, 161 * we must check for those interfaces as well (see, for 162 * example, what's done on Linux). 163 * 164 * LAN interfaces will probably have link-layer 165 * addresses; I don't know whether all implementations 166 * of "getifaddrs()" now, or in the future, will return 167 * those. 168 */ 169 if (getifaddrs(&ifap) != 0) { 170 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 171 errno, "getifaddrs"); 172 return (-1); 173 } 174 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 175 /* 176 * If this entry has a colon followed by a number at 177 * the end, we assume it's a logical interface. Those 178 * are just the way you assign multiple IP addresses to 179 * a real interface on Linux, so an entry for a logical 180 * interface should be treated like the entry for the 181 * real interface; we do that by stripping off the ":" 182 * and the number. 183 * 184 * XXX - should we do this only on Linux? 185 */ 186 p = strchr(ifa->ifa_name, ':'); 187 if (p != NULL) { 188 /* 189 * We have a ":"; is it followed by a number? 190 */ 191 q = p + 1; 192 while (PCAP_ISDIGIT(*q)) 193 q++; 194 if (*q == '\0') { 195 /* 196 * All digits after the ":" until the end. 197 * Strip off the ":" and everything after 198 * it. 199 */ 200 *p = '\0'; 201 } 202 } 203 204 /* 205 * Can we capture on this device? 206 */ 207 if (!(*check_usable)(ifa->ifa_name)) { 208 /* 209 * No. 210 */ 211 continue; 212 } 213 214 /* 215 * "ifa_addr" was apparently null on at least one 216 * interface on some system. Therefore, we supply 217 * the address and netmask only if "ifa_addr" is 218 * non-null (if there's no address, there's obviously 219 * no netmask). 220 */ 221 if (ifa->ifa_addr != NULL) { 222 addr = ifa->ifa_addr; 223 addr_size = SA_LEN(addr); 224 netmask = ifa->ifa_netmask; 225 } else { 226 addr = NULL; 227 addr_size = 0; 228 netmask = NULL; 229 } 230 231 /* 232 * Note that, on some platforms, ifa_broadaddr and 233 * ifa_dstaddr could be the same field (true on at 234 * least some versions of *BSD and macOS), so we 235 * can't just check whether the broadcast address 236 * is null and add it if so and check whether the 237 * destination address is null and add it if so. 238 * 239 * Therefore, we must also check the IFF_BROADCAST 240 * flag, and only add a broadcast address if it's 241 * set, and check the IFF_POINTTOPOINT flag, and 242 * only add a destination address if it's set (as 243 * per man page recommendations on some of those 244 * platforms). 245 */ 246 if (ifa->ifa_flags & IFF_BROADCAST && 247 ifa->ifa_broadaddr != NULL) { 248 broadaddr = ifa->ifa_broadaddr; 249 broadaddr_size = SA_LEN(broadaddr); 250 } else { 251 broadaddr = NULL; 252 broadaddr_size = 0; 253 } 254 if (ifa->ifa_flags & IFF_POINTOPOINT && 255 ifa->ifa_dstaddr != NULL) { 256 dstaddr = ifa->ifa_dstaddr; 257 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 258 } else { 259 dstaddr = NULL; 260 dstaddr_size = 0; 261 } 262 263 /* 264 * Add information for this address to the list. 265 */ 266 if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags, 267 get_flags_func, 268 addr, addr_size, netmask, addr_size, 269 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 270 errbuf) < 0) { 271 ret = -1; 272 break; 273 } 274 } 275 276 freeifaddrs(ifap); 277 278 return (ret); 279 } 280