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 #ifndef lint 36 static const char rcsid[] _U_ = 37 "@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.4.2.1 2003/11/15 23:26:39 guy Exp $ (LBL)"; 38 #endif 39 40 #ifdef HAVE_CONFIG_H 41 #include "config.h" 42 #endif 43 44 #include <sys/param.h> 45 #include <sys/file.h> 46 #include <sys/ioctl.h> 47 #include <sys/socket.h> 48 #ifdef HAVE_SYS_SOCKIO_H 49 #include <sys/sockio.h> 50 #endif 51 #include <sys/time.h> /* concession to AIX */ 52 53 struct mbuf; /* Squelch compiler warnings on some platforms for */ 54 struct rtentry; /* declarations in <net/if.h> */ 55 #include <net/if.h> 56 #include <netinet/in.h> 57 58 #include <ctype.h> 59 #include <errno.h> 60 #include <memory.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <unistd.h> 65 66 #include "pcap-int.h" 67 68 #ifdef HAVE_OS_PROTO_H 69 #include "os-proto.h" 70 #endif 71 72 /* 73 * This is fun. 74 * 75 * In older BSD systems, socket addresses were fixed-length, and 76 * "sizeof (struct sockaddr)" gave the size of the structure. 77 * All addresses fit within a "struct sockaddr". 78 * 79 * In newer BSD systems, the socket address is variable-length, and 80 * there's an "sa_len" field giving the length of the structure; 81 * this allows socket addresses to be longer than 2 bytes of family 82 * and 14 bytes of data. 83 * 84 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 85 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 86 * than "struct sockaddr"), and some use the new BSD scheme. 87 * 88 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 89 * macro that determines the size based on the address family. Other 90 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 91 * but not in the final version). 92 * 93 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have 94 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the 95 * address in an entry returned by SIOCGIFCONF. 96 */ 97 #ifndef SA_LEN 98 #ifdef HAVE_SOCKADDR_SA_LEN 99 #define SA_LEN(addr) ((addr)->sa_len) 100 #else /* HAVE_SOCKADDR_SA_LEN */ 101 #define SA_LEN(addr) (sizeof (struct sockaddr)) 102 #endif /* HAVE_SOCKADDR_SA_LEN */ 103 #endif /* SA_LEN */ 104 105 #ifdef HAVE_PROC_NET_DEV 106 /* 107 * Get from "/proc/net/dev" all interfaces listed there; if they're 108 * already in the list of interfaces we have, that won't add another 109 * instance, but if they're not, that'll add them. 110 * 111 * We don't bother getting any addresses for them; it appears you can't 112 * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and, 113 * although some other types of addresses can be fetched with SIOCGIFADDR, 114 * we don't bother with them for now. 115 * 116 * We also don't fail if we couldn't open "/proc/net/dev"; we just leave 117 * the list of interfaces as is. 118 */ 119 static int 120 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf) 121 { 122 FILE *proc_net_f; 123 char linebuf[512]; 124 int linenum; 125 unsigned char *p; 126 char name[512]; /* XXX - pick a size */ 127 char *q, *saveq; 128 struct ifreq ifrflags; 129 int ret = 0; 130 131 proc_net_f = fopen("/proc/net/dev", "r"); 132 if (proc_net_f == NULL) 133 return (0); 134 135 for (linenum = 1; 136 fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) { 137 /* 138 * Skip the first two lines - they're headers. 139 */ 140 if (linenum <= 2) 141 continue; 142 143 p = &linebuf[0]; 144 145 /* 146 * Skip leading white space. 147 */ 148 while (*p != '\0' && isspace(*p)) 149 p++; 150 if (*p == '\0' || *p == '\n') 151 continue; /* blank line */ 152 153 /* 154 * Get the interface name. 155 */ 156 q = &name[0]; 157 while (*p != '\0' && !isspace(*p)) { 158 if (*p == ':') { 159 /* 160 * This could be the separator between a 161 * name and an alias number, or it could be 162 * the separator between a name with no 163 * alias number and the next field. 164 * 165 * If there's a colon after digits, it 166 * separates the name and the alias number, 167 * otherwise it separates the name and the 168 * next field. 169 */ 170 saveq = q; 171 while (isdigit(*p)) 172 *q++ = *p++; 173 if (*p != ':') { 174 /* 175 * That was the next field, 176 * not the alias number. 177 */ 178 q = saveq; 179 } 180 break; 181 } else 182 *q++ = *p++; 183 } 184 *q = '\0'; 185 186 /* 187 * Get the flags for this interface, and skip it if 188 * it's not up. 189 */ 190 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); 191 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 192 if (errno == ENXIO) 193 continue; 194 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 195 "SIOCGIFFLAGS: %.*s: %s", 196 (int)sizeof(ifrflags.ifr_name), 197 ifrflags.ifr_name, 198 pcap_strerror(errno)); 199 ret = -1; 200 break; 201 } 202 if (!(ifrflags.ifr_flags & IFF_UP)) 203 continue; 204 205 /* 206 * Add an entry for this interface, with no addresses. 207 */ 208 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, 209 errbuf) == -1) { 210 /* 211 * Failure. 212 */ 213 ret = -1; 214 break; 215 } 216 } 217 if (ret != -1) { 218 /* 219 * Well, we didn't fail for any other reason; did we 220 * fail due to an error reading the file? 221 */ 222 if (ferror(proc_net_f)) { 223 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 224 "Error reading /proc/net/dev: %s", 225 pcap_strerror(errno)); 226 ret = -1; 227 } 228 } 229 230 (void)fclose(proc_net_f); 231 return (ret); 232 } 233 #endif /* HAVE_PROC_NET_DEV */ 234 235 /* 236 * Get a list of all interfaces that are up and that we can open. 237 * Returns -1 on error, 0 otherwise. 238 * The list, as returned through "alldevsp", may be null if no interfaces 239 * were up and could be opened. 240 * 241 * This is the implementation used on platforms that have SIOCGIFCONF but 242 * don't have any other mechanism for getting a list of interfaces. 243 * 244 * XXX - or platforms that have other, better mechanisms but for which 245 * we don't yet have code to use that mechanism; I think there's a better 246 * way on Linux, for example. 247 */ 248 int 249 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 250 { 251 pcap_if_t *devlist = NULL; 252 register int fd; 253 register struct ifreq *ifrp, *ifend, *ifnext; 254 int n; 255 struct ifconf ifc; 256 char *buf = NULL; 257 unsigned buf_size; 258 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 259 struct sockaddr *netmask, *broadaddr, *dstaddr; 260 size_t netmask_size, broadaddr_size, dstaddr_size; 261 int ret = 0; 262 263 /* 264 * Create a socket from which to fetch the list of interfaces. 265 */ 266 fd = socket(AF_INET, SOCK_DGRAM, 0); 267 if (fd < 0) { 268 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 269 "socket: %s", pcap_strerror(errno)); 270 return (-1); 271 } 272 273 /* 274 * Start with an 8K buffer, and keep growing the buffer until 275 * we get the entire interface list or fail to get it for some 276 * reason other than EINVAL (which is presumed here to mean 277 * "buffer is too small"). 278 */ 279 buf_size = 8192; 280 for (;;) { 281 buf = malloc(buf_size); 282 if (buf == NULL) { 283 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 284 "malloc: %s", pcap_strerror(errno)); 285 (void)close(fd); 286 return (-1); 287 } 288 289 ifc.ifc_len = buf_size; 290 ifc.ifc_buf = buf; 291 memset(buf, 0, buf_size); 292 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 293 && errno != EINVAL) { 294 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 295 "SIOCGIFCONF: %s", pcap_strerror(errno)); 296 (void)close(fd); 297 free(buf); 298 return (-1); 299 } 300 if (ifc.ifc_len < buf_size) 301 break; 302 free(buf); 303 buf_size *= 2; 304 } 305 306 ifrp = (struct ifreq *)buf; 307 ifend = (struct ifreq *)(buf + ifc.ifc_len); 308 309 for (; ifrp < ifend; ifrp = ifnext) { 310 /* 311 * XXX - what if this isn't an IPv4 address? Can 312 * we still get the netmask, etc. with ioctls on 313 * an IPv4 socket? 314 * 315 * The answer is probably platform-dependent, and 316 * if the answer is "no" on more than one platform, 317 * the way you work around it is probably platform- 318 * dependent as well. 319 */ 320 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 321 if (n < sizeof(*ifrp)) 322 ifnext = ifrp + 1; 323 else 324 ifnext = (struct ifreq *)((char *)ifrp + n); 325 326 /* 327 * Get the flags for this interface, and skip it if it's 328 * not up. 329 */ 330 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 331 sizeof(ifrflags.ifr_name)); 332 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 333 if (errno == ENXIO) 334 continue; 335 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 336 "SIOCGIFFLAGS: %.*s: %s", 337 (int)sizeof(ifrflags.ifr_name), 338 ifrflags.ifr_name, 339 pcap_strerror(errno)); 340 ret = -1; 341 break; 342 } 343 if (!(ifrflags.ifr_flags & IFF_UP)) 344 continue; 345 346 /* 347 * Get the netmask for this address on this interface. 348 */ 349 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 350 sizeof(ifrnetmask.ifr_name)); 351 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 352 sizeof(ifrnetmask.ifr_addr)); 353 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 354 if (errno == EADDRNOTAVAIL) { 355 /* 356 * Not available. 357 */ 358 netmask = NULL; 359 netmask_size = 0; 360 } else { 361 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 362 "SIOCGIFNETMASK: %.*s: %s", 363 (int)sizeof(ifrnetmask.ifr_name), 364 ifrnetmask.ifr_name, 365 pcap_strerror(errno)); 366 ret = -1; 367 break; 368 } 369 } else { 370 netmask = &ifrnetmask.ifr_addr; 371 netmask_size = SA_LEN(netmask); 372 } 373 374 /* 375 * Get the broadcast address for this address on this 376 * interface (if any). 377 */ 378 if (ifrflags.ifr_flags & IFF_BROADCAST) { 379 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 380 sizeof(ifrbroadaddr.ifr_name)); 381 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 382 sizeof(ifrbroadaddr.ifr_addr)); 383 if (ioctl(fd, SIOCGIFBRDADDR, 384 (char *)&ifrbroadaddr) < 0) { 385 if (errno == EADDRNOTAVAIL) { 386 /* 387 * Not available. 388 */ 389 broadaddr = NULL; 390 broadaddr_size = 0; 391 } else { 392 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 393 "SIOCGIFBRDADDR: %.*s: %s", 394 (int)sizeof(ifrbroadaddr.ifr_name), 395 ifrbroadaddr.ifr_name, 396 pcap_strerror(errno)); 397 ret = -1; 398 break; 399 } 400 } else { 401 broadaddr = &ifrbroadaddr.ifr_broadaddr; 402 broadaddr_size = SA_LEN(broadaddr); 403 } 404 } else { 405 /* 406 * Not a broadcast interface, so no broadcast 407 * address. 408 */ 409 broadaddr = NULL; 410 broadaddr_size = 0; 411 } 412 413 /* 414 * Get the destination address for this address on this 415 * interface (if any). 416 */ 417 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 418 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 419 sizeof(ifrdstaddr.ifr_name)); 420 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 421 sizeof(ifrdstaddr.ifr_addr)); 422 if (ioctl(fd, SIOCGIFDSTADDR, 423 (char *)&ifrdstaddr) < 0) { 424 if (errno == EADDRNOTAVAIL) { 425 /* 426 * Not available. 427 */ 428 dstaddr = NULL; 429 dstaddr_size = 0; 430 } else { 431 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 432 "SIOCGIFDSTADDR: %.*s: %s", 433 (int)sizeof(ifrdstaddr.ifr_name), 434 ifrdstaddr.ifr_name, 435 pcap_strerror(errno)); 436 ret = -1; 437 break; 438 } 439 } else { 440 dstaddr = &ifrdstaddr.ifr_dstaddr; 441 dstaddr_size = SA_LEN(dstaddr); 442 } 443 } else { 444 /* 445 * Not a point-to-point interface, so no destination 446 * address. 447 */ 448 dstaddr = NULL; 449 dstaddr_size = 0; 450 } 451 452 /* 453 * Add information for this address to the list. 454 */ 455 if (add_addr_to_iflist(&devlist, ifrp->ifr_name, 456 ifrflags.ifr_flags, &ifrp->ifr_addr, 457 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size, 458 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 459 errbuf) < 0) { 460 ret = -1; 461 break; 462 } 463 } 464 free(buf); 465 466 #ifdef HAVE_PROC_NET_DEV 467 if (ret != -1) { 468 /* 469 * We haven't had any errors yet; now read "/proc/net/dev", 470 * and add to the list of interfaces all interfaces listed 471 * there that we don't already have, because, on Linux, 472 * SIOCGIFCONF reports only interfaces with IPv4 addresses, 473 * so you need to read "/proc/net/dev" to get the names of 474 * the rest of the interfaces. 475 */ 476 ret = scan_proc_net_dev(&devlist, fd, errbuf); 477 } 478 #endif 479 (void)close(fd); 480 481 if (ret != -1) { 482 /* 483 * We haven't had any errors yet; do any platform-specific 484 * operations to add devices. 485 */ 486 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 487 ret = -1; 488 } 489 490 if (ret == -1) { 491 /* 492 * We had an error; free the list we've been constructing. 493 */ 494 if (devlist != NULL) { 495 pcap_freealldevs(devlist); 496 devlist = NULL; 497 } 498 } 499 500 *alldevsp = devlist; 501 return (ret); 502 } 503