1 /* $NetBSD: fad-gifc.c,v 1.1.1.4 2013/12/31 16:57:26 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 #ifndef lint 38 static const char rcsid[] _U_ = 39 "@(#) Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.12 2008-08-06 07:34:09 guy Exp (LBL)"; 40 #endif 41 42 #ifdef HAVE_CONFIG_H 43 #include "config.h" 44 #endif 45 46 #include <sys/param.h> 47 #include <sys/ioctl.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_SOCKIO_H 50 #include <sys/sockio.h> 51 #endif 52 #include <sys/time.h> /* concession to AIX */ 53 54 struct mbuf; /* Squelch compiler warnings on some platforms for */ 55 struct rtentry; /* declarations in <net/if.h> */ 56 #include <net/if.h> 57 #include <netinet/in.h> 58 59 #include <ctype.h> 60 #include <errno.h> 61 #include <memory.h> 62 #include <stdio.h> 63 #include <stdlib.h> 64 #include <string.h> 65 #include <unistd.h> 66 67 #include "pcap-int.h" 68 69 #ifdef HAVE_OS_PROTO_H 70 #include "os-proto.h" 71 #endif 72 73 /* 74 * This is fun. 75 * 76 * In older BSD systems, socket addresses were fixed-length, and 77 * "sizeof (struct sockaddr)" gave the size of the structure. 78 * All addresses fit within a "struct sockaddr". 79 * 80 * In newer BSD systems, the socket address is variable-length, and 81 * there's an "sa_len" field giving the length of the structure; 82 * this allows socket addresses to be longer than 2 bytes of family 83 * and 14 bytes of data. 84 * 85 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 86 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 87 * than "struct sockaddr"), and some use the new BSD scheme. 88 * 89 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 90 * macro that determines the size based on the address family. Other 91 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 92 * but not in the final version). 93 * 94 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have 95 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the 96 * address in an entry returned by SIOCGIFCONF. 97 */ 98 #ifndef SA_LEN 99 #ifdef HAVE_SOCKADDR_SA_LEN 100 #define SA_LEN(addr) ((addr)->sa_len) 101 #else /* HAVE_SOCKADDR_SA_LEN */ 102 #define SA_LEN(addr) (sizeof (struct sockaddr)) 103 #endif /* HAVE_SOCKADDR_SA_LEN */ 104 #endif /* SA_LEN */ 105 106 /* 107 * This is also fun. 108 * 109 * There is no ioctl that returns the amount of space required for all 110 * the data that SIOCGIFCONF could return, and if a buffer is supplied 111 * that's not large enough for all the data SIOCGIFCONF could return, 112 * on at least some platforms it just returns the data that'd fit with 113 * no indication that there wasn't enough room for all the data, much 114 * less an indication of how much more room is required. 115 * 116 * The only way to ensure that we got all the data is to pass a buffer 117 * large enough that the amount of space in the buffer *not* filled in 118 * is greater than the largest possible entry. 119 * 120 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption 121 * that no address is more than 255 bytes (on systems where the "sa_len" 122 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the 123 * case, and addresses are unlikely to be bigger than that in any case). 124 */ 125 #define MAX_SA_LEN 255 126 127 /* 128 * Get a list of all interfaces that are up and that we can open. 129 * Returns -1 on error, 0 otherwise. 130 * The list, as returned through "alldevsp", may be null if no interfaces 131 * were up and could be opened. 132 * 133 * This is the implementation used on platforms that have SIOCGIFCONF but 134 * don't have any other mechanism for getting a list of interfaces. 135 * 136 * XXX - or platforms that have other, better mechanisms but for which 137 * we don't yet have code to use that mechanism; I think there's a better 138 * way on Linux, for example, but if that better way is "getifaddrs()", 139 * we already have that. 140 */ 141 int 142 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf) 143 { 144 pcap_if_t *devlist = NULL; 145 register int fd; 146 register struct ifreq *ifrp, *ifend, *ifnext; 147 int n; 148 struct ifconf ifc; 149 char *buf = NULL; 150 unsigned buf_size; 151 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 152 char *p, *q; 153 #endif 154 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 155 struct sockaddr *netmask, *broadaddr, *dstaddr; 156 size_t netmask_size, broadaddr_size, dstaddr_size; 157 int ret = 0; 158 159 /* 160 * Create a socket from which to fetch the list of interfaces. 161 */ 162 fd = socket(AF_INET, SOCK_DGRAM, 0); 163 if (fd < 0) { 164 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 165 "socket: %s", pcap_strerror(errno)); 166 return (-1); 167 } 168 169 /* 170 * Start with an 8K buffer, and keep growing the buffer until 171 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 172 * bytes left over in the buffer or we fail to get the 173 * interface list for some reason other than EINVAL (which is 174 * presumed here to mean "buffer is too small"). 175 */ 176 buf_size = 8192; 177 for (;;) { 178 buf = malloc(buf_size); 179 if (buf == NULL) { 180 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 181 "malloc: %s", pcap_strerror(errno)); 182 (void)close(fd); 183 return (-1); 184 } 185 186 ifc.ifc_len = buf_size; 187 ifc.ifc_buf = buf; 188 memset(buf, 0, buf_size); 189 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 190 && errno != EINVAL) { 191 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 192 "SIOCGIFCONF: %s", pcap_strerror(errno)); 193 (void)close(fd); 194 free(buf); 195 return (-1); 196 } 197 if (ifc.ifc_len < buf_size && 198 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 199 break; 200 free(buf); 201 buf_size *= 2; 202 } 203 204 ifrp = (struct ifreq *)buf; 205 ifend = (struct ifreq *)(buf + ifc.ifc_len); 206 207 for (; ifrp < ifend; ifrp = ifnext) { 208 /* 209 * XXX - what if this isn't an IPv4 address? Can 210 * we still get the netmask, etc. with ioctls on 211 * an IPv4 socket? 212 * 213 * The answer is probably platform-dependent, and 214 * if the answer is "no" on more than one platform, 215 * the way you work around it is probably platform- 216 * dependent as well. 217 */ 218 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 219 if (n < sizeof(*ifrp)) 220 ifnext = ifrp + 1; 221 else 222 ifnext = (struct ifreq *)((char *)ifrp + n); 223 224 /* 225 * XXX - The 32-bit compatibility layer for Linux on IA-64 226 * is slightly broken. It correctly converts the structures 227 * to and from kernel land from 64 bit to 32 bit but 228 * doesn't update ifc.ifc_len, leaving it larger than the 229 * amount really used. This means we read off the end 230 * of the buffer and encounter an interface with an 231 * "empty" name. Since this is highly unlikely to ever 232 * occur in a valid case we can just finish looking for 233 * interfaces if we see an empty name. 234 */ 235 if (!(*ifrp->ifr_name)) 236 break; 237 238 /* 239 * Skip entries that begin with "dummy". 240 * XXX - what are these? Is this Linux-specific? 241 * Are there platforms on which we shouldn't do this? 242 */ 243 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 244 continue; 245 246 /* 247 * Get the flags for this interface, and skip it if it's 248 * not up. 249 */ 250 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 251 sizeof(ifrflags.ifr_name)); 252 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 253 if (errno == ENXIO) 254 continue; 255 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 256 "SIOCGIFFLAGS: %.*s: %s", 257 (int)sizeof(ifrflags.ifr_name), 258 ifrflags.ifr_name, 259 pcap_strerror(errno)); 260 ret = -1; 261 break; 262 } 263 if (!(ifrflags.ifr_flags & IFF_UP)) 264 continue; 265 266 /* 267 * Get the netmask for this address on this interface. 268 */ 269 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 270 sizeof(ifrnetmask.ifr_name)); 271 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 272 sizeof(ifrnetmask.ifr_addr)); 273 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 274 if (errno == EADDRNOTAVAIL) { 275 /* 276 * Not available. 277 */ 278 netmask = NULL; 279 netmask_size = 0; 280 } else { 281 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 282 "SIOCGIFNETMASK: %.*s: %s", 283 (int)sizeof(ifrnetmask.ifr_name), 284 ifrnetmask.ifr_name, 285 pcap_strerror(errno)); 286 ret = -1; 287 break; 288 } 289 } else { 290 netmask = &ifrnetmask.ifr_addr; 291 netmask_size = SA_LEN(netmask); 292 } 293 294 /* 295 * Get the broadcast address for this address on this 296 * interface (if any). 297 */ 298 if (ifrflags.ifr_flags & IFF_BROADCAST) { 299 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 300 sizeof(ifrbroadaddr.ifr_name)); 301 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 302 sizeof(ifrbroadaddr.ifr_addr)); 303 if (ioctl(fd, SIOCGIFBRDADDR, 304 (char *)&ifrbroadaddr) < 0) { 305 if (errno == EADDRNOTAVAIL) { 306 /* 307 * Not available. 308 */ 309 broadaddr = NULL; 310 broadaddr_size = 0; 311 } else { 312 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 313 "SIOCGIFBRDADDR: %.*s: %s", 314 (int)sizeof(ifrbroadaddr.ifr_name), 315 ifrbroadaddr.ifr_name, 316 pcap_strerror(errno)); 317 ret = -1; 318 break; 319 } 320 } else { 321 broadaddr = &ifrbroadaddr.ifr_broadaddr; 322 broadaddr_size = SA_LEN(broadaddr); 323 } 324 } else { 325 /* 326 * Not a broadcast interface, so no broadcast 327 * address. 328 */ 329 broadaddr = NULL; 330 broadaddr_size = 0; 331 } 332 333 /* 334 * Get the destination address for this address on this 335 * interface (if any). 336 */ 337 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 338 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 339 sizeof(ifrdstaddr.ifr_name)); 340 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 341 sizeof(ifrdstaddr.ifr_addr)); 342 if (ioctl(fd, SIOCGIFDSTADDR, 343 (char *)&ifrdstaddr) < 0) { 344 if (errno == EADDRNOTAVAIL) { 345 /* 346 * Not available. 347 */ 348 dstaddr = NULL; 349 dstaddr_size = 0; 350 } else { 351 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 352 "SIOCGIFDSTADDR: %.*s: %s", 353 (int)sizeof(ifrdstaddr.ifr_name), 354 ifrdstaddr.ifr_name, 355 pcap_strerror(errno)); 356 ret = -1; 357 break; 358 } 359 } else { 360 dstaddr = &ifrdstaddr.ifr_dstaddr; 361 dstaddr_size = SA_LEN(dstaddr); 362 } 363 } else { 364 /* 365 * Not a point-to-point interface, so no destination 366 * address. 367 */ 368 dstaddr = NULL; 369 dstaddr_size = 0; 370 } 371 372 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 373 /* 374 * If this entry has a colon followed by a number at 375 * the end, it's a logical interface. Those are just 376 * the way you assign multiple IP addresses to a real 377 * interface, so an entry for a logical interface should 378 * be treated like the entry for the real interface; 379 * we do that by stripping off the ":" and the number. 380 */ 381 p = strchr(ifrp->ifr_name, ':'); 382 if (p != NULL) { 383 /* 384 * We have a ":"; is it followed by a number? 385 */ 386 q = p + 1; 387 while (isdigit((unsigned char)*q)) 388 q++; 389 if (*q == '\0') { 390 /* 391 * All digits after the ":" until the end. 392 * Strip off the ":" and everything after 393 * it. 394 */ 395 *p = '\0'; 396 } 397 } 398 #endif 399 400 /* 401 * Add information for this address to the list. 402 */ 403 if (add_addr_to_iflist(&devlist, ifrp->ifr_name, 404 ifrflags.ifr_flags, &ifrp->ifr_addr, 405 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size, 406 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 407 errbuf) < 0) { 408 ret = -1; 409 break; 410 } 411 } 412 free(buf); 413 (void)close(fd); 414 415 if (ret == -1) { 416 /* 417 * We had an error; free the list we've been constructing. 418 */ 419 if (devlist != NULL) { 420 pcap_freealldevs(devlist); 421 devlist = NULL; 422 } 423 } 424 425 *alldevsp = devlist; 426 return (ret); 427 } 428