1 /* $NetBSD: fad-getad.c,v 1.4 2018/09/03 15:26:43 christos Exp $ */ 2 3 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */ 4 /* 5 * Copyright (c) 1994, 1995, 1996, 1997, 1998 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the Computer Systems 19 * Engineering Group at Lawrence Berkeley Laboratory. 20 * 4. Neither the name of the University nor of the Laboratory may be used 21 * to endorse or promote products derived from this software without 22 * specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __RCSID("$NetBSD: fad-getad.c,v 1.4 2018/09/03 15:26:43 christos Exp $"); 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 /* 64 * We don't do this on Solaris 11 and later, as it appears there aren't 65 * any AF_PACKET addresses on interfaces, so we don't need this, and 66 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>, 67 * and their definitions of some data structures collide. 68 */ 69 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) 70 # ifdef HAVE_NETPACKET_PACKET_H 71 /* Linux distributions with newer glibc */ 72 # include <netpacket/packet.h> 73 # else /* HAVE_NETPACKET_PACKET_H */ 74 /* LynxOS, Linux distributions with older glibc */ 75 # ifdef __Lynx__ 76 /* LynxOS */ 77 # include <netpacket/if_packet.h> 78 # else /* __Lynx__ */ 79 /* Linux */ 80 # include <linux/types.h> 81 # include <linux/if_packet.h> 82 # endif /* __Lynx__ */ 83 # endif /* HAVE_NETPACKET_PACKET_H */ 84 #endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */ 85 86 /* 87 * This is fun. 88 * 89 * In older BSD systems, socket addresses were fixed-length, and 90 * "sizeof (struct sockaddr)" gave the size of the structure. 91 * All addresses fit within a "struct sockaddr". 92 * 93 * In newer BSD systems, the socket address is variable-length, and 94 * there's an "sa_len" field giving the length of the structure; 95 * this allows socket addresses to be longer than 2 bytes of family 96 * and 14 bytes of data. 97 * 98 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 99 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 100 * than "struct sockaddr"), and some use the new BSD scheme. 101 * 102 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 103 * macro that determines the size based on the address family. Other 104 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 105 * but not in the final version). On the latter systems, we explicitly 106 * check the AF_ type to determine the length; we assume that on 107 * all those systems we have "struct sockaddr_storage". 108 */ 109 #ifndef SA_LEN 110 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN 111 #define SA_LEN(addr) ((addr)->sa_len) 112 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 113 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE 114 static size_t 115 get_sa_len(struct sockaddr *addr) 116 { 117 switch (addr->sa_family) { 118 119 #ifdef AF_INET 120 case AF_INET: 121 return (sizeof (struct sockaddr_in)); 122 #endif 123 124 #ifdef AF_INET6 125 case AF_INET6: 126 return (sizeof (struct sockaddr_in6)); 127 #endif 128 129 #if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) 130 case AF_PACKET: 131 return (sizeof (struct sockaddr_ll)); 132 #endif 133 134 default: 135 return (sizeof (struct sockaddr)); 136 } 137 } 138 #define SA_LEN(addr) (get_sa_len(addr)) 139 #else /* HAVE_STRUCT_SOCKADDR_STORAGE */ 140 #define SA_LEN(addr) (sizeof (struct sockaddr)) 141 #endif /* HAVE_STRUCT_SOCKADDR_STORAGE */ 142 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 143 #endif /* SA_LEN */ 144 145 /* 146 * Get a list of all interfaces that are up and that we can open. 147 * Returns -1 on error, 0 otherwise. 148 * The list, as returned through "alldevsp", may be null if no interfaces 149 * could be opened. 150 */ 151 int 152 pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, 153 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 154 { 155 struct ifaddrs *ifap, *ifa; 156 struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; 157 size_t addr_size, broadaddr_size, dstaddr_size; 158 int ret = 0; 159 char *p, *q; 160 161 /* 162 * Get the list of interface addresses. 163 * 164 * Note: this won't return information about interfaces 165 * with no addresses, so, if a platform has interfaces 166 * with no interfaces on which traffic can be captured, 167 * we must check for those interfaces as well (see, for 168 * example, what's done on Linux). 169 * 170 * LAN interfaces will probably have link-layer 171 * addresses; I don't know whether all implementations 172 * of "getifaddrs()" now, or in the future, will return 173 * those. 174 */ 175 if (getifaddrs(&ifap) != 0) { 176 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 177 errno, "getifaddrs"); 178 return (-1); 179 } 180 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 181 /* 182 * If this entry has a colon followed by a number at 183 * the end, we assume it's a logical interface. Those 184 * are just the way you assign multiple IP addresses to 185 * a real interface on Linux, so an entry for a logical 186 * interface should be treated like the entry for the 187 * real interface; we do that by stripping off the ":" 188 * and the number. 189 * 190 * XXX - should we do this only on Linux? 191 */ 192 p = strchr(ifa->ifa_name, ':'); 193 if (p != NULL) { 194 /* 195 * We have a ":"; is it followed by a number? 196 */ 197 q = p + 1; 198 while (isdigit((unsigned char)*q)) 199 q++; 200 if (*q == '\0') { 201 /* 202 * All digits after the ":" until the end. 203 * Strip off the ":" and everything after 204 * it. 205 */ 206 *p = '\0'; 207 } 208 } 209 210 /* 211 * Can we capture on this device? 212 */ 213 if (!(*check_usable)(ifa->ifa_name)) { 214 /* 215 * No. 216 */ 217 continue; 218 } 219 220 /* 221 * "ifa_addr" was apparently null on at least one 222 * interface on some system. Therefore, we supply 223 * the address and netmask only if "ifa_addr" is 224 * non-null (if there's no address, there's obviously 225 * no netmask). 226 */ 227 if (ifa->ifa_addr != NULL) { 228 addr = ifa->ifa_addr; 229 addr_size = SA_LEN(addr); 230 netmask = ifa->ifa_netmask; 231 } else { 232 addr = NULL; 233 addr_size = 0; 234 netmask = NULL; 235 } 236 237 /* 238 * Note that, on some platforms, ifa_broadaddr and 239 * ifa_dstaddr could be the same field (true on at 240 * least some versions of *BSD and macOS), so we 241 * can't just check whether the broadcast address 242 * is null and add it if so and check whether the 243 * destination address is null and add it if so. 244 * 245 * Therefore, we must also check the IFF_BROADCAST 246 * flag, and only add a broadcast address if it's 247 * set, and check the IFF_POINTTOPOINT flag, and 248 * only add a destination address if it's set (as 249 * per man page recommendations on some of those 250 * platforms). 251 */ 252 if (ifa->ifa_flags & IFF_BROADCAST && 253 ifa->ifa_broadaddr != NULL) { 254 broadaddr = ifa->ifa_broadaddr; 255 broadaddr_size = SA_LEN(broadaddr); 256 } else { 257 broadaddr = NULL; 258 broadaddr_size = 0; 259 } 260 if (ifa->ifa_flags & IFF_POINTOPOINT && 261 ifa->ifa_dstaddr != NULL) { 262 dstaddr = ifa->ifa_dstaddr; 263 dstaddr_size = SA_LEN(ifa->ifa_dstaddr); 264 } else { 265 dstaddr = NULL; 266 dstaddr_size = 0; 267 } 268 269 /* 270 * Add information for this address to the list. 271 */ 272 if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags, 273 get_flags_func, 274 addr, addr_size, netmask, addr_size, 275 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 276 errbuf) < 0) { 277 ret = -1; 278 break; 279 } 280 } 281 282 freeifaddrs(ifap); 283 284 return (ret); 285 } 286