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_STRUCT_SOCKADDR_SA_LEN 106 #define SA_LEN(addr) ((addr)->sa_len) 107 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 108 #ifdef HAVE_STRUCT_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_STRUCT_SOCKADDR_STORAGE */ 135 #define SA_LEN(addr) (sizeof (struct sockaddr)) 136 #endif /* HAVE_STRUCT_SOCKADDR_STORAGE */ 137 #endif /* HAVE_STRUCT_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_list_t *devlistp, char *errbuf, 148 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 149 { 150 struct ifaddrs *ifap, *ifa; 151 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 152 size_t addr_size, broadaddr_size, dstaddr_size; 153 int ret = 0; 154 char *p, *q; 155 156 /* 157 * Get the list of interface addresses. 158 * 159 * Note: this won't return information about interfaces 160 * with no addresses, so, if a platform has interfaces 161 * with no interfaces on which traffic can be captured, 162 * we must check for those interfaces as well (see, for 163 * example, what's done on Linux). 164 * 165 * LAN interfaces will probably have link-layer 166 * addresses; I don't know whether all implementations 167 * of "getifaddrs()" now, or in the future, will return 168 * those. 169 */ 170 if (getifaddrs(&ifap) != 0) { 171 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 172 errno, "getifaddrs"); 173 return (-1); 174 } 175 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 176 /* 177 * If this entry has a colon followed by a number at 178 * the end, we assume it's a logical interface. Those 179 * are just the way you assign multiple IP addresses to 180 * a real interface on Linux, so an entry for a logical 181 * interface should be treated like the entry for the 182 * real interface; we do that by stripping off the ":" 183 * and the number. 184 * 185 * XXX - should we do this only on Linux? 186 */ 187 p = strchr(ifa->ifa_name, ':'); 188 if (p != NULL) { 189 /* 190 * We have a ":"; is it followed by a number? 191 */ 192 q = p + 1; 193 while (isdigit((unsigned char)*q)) 194 q++; 195 if (*q == '\0') { 196 /* 197 * All digits after the ":" until the end. 198 * Strip off the ":" and everything after 199 * it. 200 */ 201 *p = '\0'; 202 } 203 } 204 205 /* 206 * Can we capture on this device? 207 */ 208 if (!(*check_usable)(ifa->ifa_name)) { 209 /* 210 * No. 211 */ 212 continue; 213 } 214 215 /* 216 * "ifa_addr" was apparently null on at least one 217 * interface on some system. Therefore, we supply 218 * the address and netmask only if "ifa_addr" is 219 * non-null (if there's no address, there's obviously 220 * no netmask). 221 */ 222 if (ifa->ifa_addr != NULL) { 223 addr = ifa->ifa_addr; 224 addr_size = SA_LEN(addr); 225 netmask = ifa->ifa_netmask; 226 } else { 227 addr = NULL; 228 addr_size = 0; 229 netmask = NULL; 230 } 231 232 /* 233 * Note that, on some platforms, ifa_broadaddr and 234 * ifa_dstaddr could be the same field (true on at 235 * least some versions of *BSD and macOS), so we 236 * can't just check whether the broadcast address 237 * is null and add it if so and check whether the 238 * destination address is null and add it if so. 239 * 240 * Therefore, we must also check the IFF_BROADCAST 241 * flag, and only add a broadcast address if it's 242 * set, and check the IFF_POINTTOPOINT flag, and 243 * only add a destination address if it's set (as 244 * per man page recommendations on some of those 245 * platforms). 246 */ 247 if (ifa->ifa_flags & IFF_BROADCAST && 248 ifa->ifa_broadaddr != NULL) { 249 broadaddr = ifa->ifa_broadaddr; 250 broadaddr_size = SA_LEN(broadaddr); 251 } else { 252 broadaddr = NULL; 253 broadaddr_size = 0; 254 } 255 if (ifa->ifa_flags & IFF_POINTOPOINT && 256 ifa->ifa_dstaddr != NULL) { 257 dstaddr = ifa->ifa_dstaddr; 258 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 259 } else { 260 dstaddr = NULL; 261 dstaddr_size = 0; 262 } 263 264 /* 265 * Add information for this address to the list. 266 */ 267 if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags, 268 get_flags_func, 269 addr, addr_size, netmask, addr_size, 270 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 271 errbuf) < 0) { 272 ret = -1; 273 break; 274 } 275 } 276 277 freeifaddrs(ifap); 278 279 return (ret); 280 } 281
