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 1.8.2.2 2005/06/29 06:43:31 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 /* 106 * This is also fun. 107 * 108 * There is no ioctl that returns the amount of space required for all 109 * the data that SIOCGIFCONF could return, and if a buffer is supplied 110 * that's not large enough for all the data SIOCGIFCONF could return, 111 * on at least some platforms it just returns the data that'd fit with 112 * no indication that there wasn't enough room for all the data, much 113 * less an indication of how much more room is required. 114 * 115 * The only way to ensure that we got all the data is to pass a buffer 116 * large enough that the amount of space in the buffer *not* filled in 117 * is greater than the largest possible entry. 118 * 119 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption 120 * that no address is more than 255 bytes (on systems where the "sa_len" 121 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the 122 * case, and addresses are unlikely to be bigger than that in any case). 123 */ 124 #define MAX_SA_LEN 255 125 126 #ifdef HAVE_PROC_NET_DEV 127 /* 128 * Get from "/proc/net/dev" all interfaces listed there; if they're 129 * already in the list of interfaces we have, that won't add another 130 * instance, but if they're not, that'll add them. 131 * 132 * We don't bother getting any addresses for them; it appears you can't 133 * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and, 134 * although some other types of addresses can be fetched with SIOCGIFADDR, 135 * we don't bother with them for now. 136 * 137 * We also don't fail if we couldn't open "/proc/net/dev"; we just leave 138 * the list of interfaces as is. 139 */ 140 static int 141 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf) 142 { 143 FILE *proc_net_f; 144 char linebuf[512]; 145 int linenum; 146 unsigned char *p; 147 char name[512]; /* XXX - pick a size */ 148 char *q, *saveq; 149 struct ifreq ifrflags; 150 int ret = 0; 151 152 proc_net_f = fopen("/proc/net/dev", "r"); 153 if (proc_net_f == NULL) 154 return (0); 155 156 for (linenum = 1; 157 fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) { 158 /* 159 * Skip the first two lines - they're headers. 160 */ 161 if (linenum <= 2) 162 continue; 163 164 p = &linebuf[0]; 165 166 /* 167 * Skip leading white space. 168 */ 169 while (*p != '\0' && isspace(*p)) 170 p++; 171 if (*p == '\0' || *p == '\n') 172 continue; /* blank line */ 173 174 /* 175 * Get the interface name. 176 */ 177 q = &name[0]; 178 while (*p != '\0' && !isspace(*p)) { 179 if (*p == ':') { 180 /* 181 * This could be the separator between a 182 * name and an alias number, or it could be 183 * the separator between a name with no 184 * alias number and the next field. 185 * 186 * If there's a colon after digits, it 187 * separates the name and the alias number, 188 * otherwise it separates the name and the 189 * next field. 190 */ 191 saveq = q; 192 while (isdigit(*p)) 193 *q++ = *p++; 194 if (*p != ':') { 195 /* 196 * That was the next field, 197 * not the alias number. 198 */ 199 q = saveq; 200 } 201 break; 202 } else 203 *q++ = *p++; 204 } 205 *q = '\0'; 206 207 /* 208 * Get the flags for this interface, and skip it if 209 * it's not up. 210 */ 211 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); 212 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 213 if (errno == ENXIO) 214 continue; 215 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 216 "SIOCGIFFLAGS: %.*s: %s", 217 (int)sizeof(ifrflags.ifr_name), 218 ifrflags.ifr_name, 219 pcap_strerror(errno)); 220 ret = -1; 221 break; 222 } 223 if (!(ifrflags.ifr_flags & IFF_UP)) 224 continue; 225 226 /* 227 * Add an entry for this interface, with no addresses. 228 */ 229 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, 230 errbuf) == -1) { 231 /* 232 * Failure. 233 */ 234 ret = -1; 235 break; 236 } 237 } 238 if (ret != -1) { 239 /* 240 * Well, we didn't fail for any other reason; did we 241 * fail due to an error reading the file? 242 */ 243 if (ferror(proc_net_f)) { 244 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 245 "Error reading /proc/net/dev: %s", 246 pcap_strerror(errno)); 247 ret = -1; 248 } 249 } 250 251 (void)fclose(proc_net_f); 252 return (ret); 253 } 254 #endif /* HAVE_PROC_NET_DEV */ 255 256 /* 257 * Get a list of all interfaces that are up and that we can open. 258 * Returns -1 on error, 0 otherwise. 259 * The list, as returned through "alldevsp", may be null if no interfaces 260 * were up and could be opened. 261 * 262 * This is the implementation used on platforms that have SIOCGIFCONF but 263 * don't have any other mechanism for getting a list of interfaces. 264 * 265 * XXX - or platforms that have other, better mechanisms but for which 266 * we don't yet have code to use that mechanism; I think there's a better 267 * way on Linux, for example. 268 */ 269 int 270 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) 271 { 272 pcap_if_t *devlist = NULL; 273 register int fd; 274 register struct ifreq *ifrp, *ifend, *ifnext; 275 int n; 276 struct ifconf ifc; 277 char *buf = NULL; 278 unsigned buf_size; 279 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 280 char *p, *q; 281 #endif 282 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 283 struct sockaddr *netmask, *broadaddr, *dstaddr; 284 size_t netmask_size, broadaddr_size, dstaddr_size; 285 int ret = 0; 286 287 /* 288 * Create a socket from which to fetch the list of interfaces. 289 */ 290 fd = socket(AF_INET, SOCK_DGRAM, 0); 291 if (fd < 0) { 292 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 293 "socket: %s", pcap_strerror(errno)); 294 return (-1); 295 } 296 297 /* 298 * Start with an 8K buffer, and keep growing the buffer until 299 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 300 * bytes left over in the buffer or we fail to get the 301 * interface list for some reason other than EINVAL (which is 302 * presumed here to mean "buffer is too small"). 303 */ 304 buf_size = 8192; 305 for (;;) { 306 buf = malloc(buf_size); 307 if (buf == NULL) { 308 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 309 "malloc: %s", pcap_strerror(errno)); 310 (void)close(fd); 311 return (-1); 312 } 313 314 ifc.ifc_len = buf_size; 315 ifc.ifc_buf = buf; 316 memset(buf, 0, buf_size); 317 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 318 && errno != EINVAL) { 319 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 320 "SIOCGIFCONF: %s", pcap_strerror(errno)); 321 (void)close(fd); 322 free(buf); 323 return (-1); 324 } 325 if (ifc.ifc_len < buf_size && 326 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 327 break; 328 free(buf); 329 buf_size *= 2; 330 } 331 332 ifrp = (struct ifreq *)buf; 333 ifend = (struct ifreq *)(buf + ifc.ifc_len); 334 335 for (; ifrp < ifend; ifrp = ifnext) { 336 /* 337 * XXX - what if this isn't an IPv4 address? Can 338 * we still get the netmask, etc. with ioctls on 339 * an IPv4 socket? 340 * 341 * The answer is probably platform-dependent, and 342 * if the answer is "no" on more than one platform, 343 * the way you work around it is probably platform- 344 * dependent as well. 345 */ 346 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 347 if (n < sizeof(*ifrp)) 348 ifnext = ifrp + 1; 349 else 350 ifnext = (struct ifreq *)((char *)ifrp + n); 351 352 /* 353 * XXX - The 32-bit compatibility layer for Linux on IA-64 354 * is slightly broken. It correctly converts the structures 355 * to and from kernel land from 64 bit to 32 bit but 356 * doesn't update ifc.ifc_len, leaving it larger than the 357 * amount really used. This means we read off the end 358 * of the buffer and encounter an interface with an 359 * "empty" name. Since this is highly unlikely to ever 360 * occur in a valid case we can just finish looking for 361 * interfaces if we see an empty name. 362 */ 363 if (!(*ifrp->ifr_name)) 364 break; 365 366 /* 367 * Skip entries that begin with "dummy". 368 * XXX - what are these? Is this Linux-specific? 369 * Are there platforms on which we shouldn't do this? 370 */ 371 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 372 continue; 373 374 /* 375 * Get the flags for this interface, and skip it if it's 376 * not up. 377 */ 378 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 379 sizeof(ifrflags.ifr_name)); 380 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 381 if (errno == ENXIO) 382 continue; 383 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 384 "SIOCGIFFLAGS: %.*s: %s", 385 (int)sizeof(ifrflags.ifr_name), 386 ifrflags.ifr_name, 387 pcap_strerror(errno)); 388 ret = -1; 389 break; 390 } 391 if (!(ifrflags.ifr_flags & IFF_UP)) 392 continue; 393 394 /* 395 * Get the netmask for this address on this interface. 396 */ 397 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 398 sizeof(ifrnetmask.ifr_name)); 399 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 400 sizeof(ifrnetmask.ifr_addr)); 401 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 402 if (errno == EADDRNOTAVAIL) { 403 /* 404 * Not available. 405 */ 406 netmask = NULL; 407 netmask_size = 0; 408 } else { 409 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 410 "SIOCGIFNETMASK: %.*s: %s", 411 (int)sizeof(ifrnetmask.ifr_name), 412 ifrnetmask.ifr_name, 413 pcap_strerror(errno)); 414 ret = -1; 415 break; 416 } 417 } else { 418 netmask = &ifrnetmask.ifr_addr; 419 netmask_size = SA_LEN(netmask); 420 } 421 422 /* 423 * Get the broadcast address for this address on this 424 * interface (if any). 425 */ 426 if (ifrflags.ifr_flags & IFF_BROADCAST) { 427 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 428 sizeof(ifrbroadaddr.ifr_name)); 429 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 430 sizeof(ifrbroadaddr.ifr_addr)); 431 if (ioctl(fd, SIOCGIFBRDADDR, 432 (char *)&ifrbroadaddr) < 0) { 433 if (errno == EADDRNOTAVAIL) { 434 /* 435 * Not available. 436 */ 437 broadaddr = NULL; 438 broadaddr_size = 0; 439 } else { 440 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 441 "SIOCGIFBRDADDR: %.*s: %s", 442 (int)sizeof(ifrbroadaddr.ifr_name), 443 ifrbroadaddr.ifr_name, 444 pcap_strerror(errno)); 445 ret = -1; 446 break; 447 } 448 } else { 449 broadaddr = &ifrbroadaddr.ifr_broadaddr; 450 broadaddr_size = SA_LEN(broadaddr); 451 } 452 } else { 453 /* 454 * Not a broadcast interface, so no broadcast 455 * address. 456 */ 457 broadaddr = NULL; 458 broadaddr_size = 0; 459 } 460 461 /* 462 * Get the destination address for this address on this 463 * interface (if any). 464 */ 465 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 466 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 467 sizeof(ifrdstaddr.ifr_name)); 468 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 469 sizeof(ifrdstaddr.ifr_addr)); 470 if (ioctl(fd, SIOCGIFDSTADDR, 471 (char *)&ifrdstaddr) < 0) { 472 if (errno == EADDRNOTAVAIL) { 473 /* 474 * Not available. 475 */ 476 dstaddr = NULL; 477 dstaddr_size = 0; 478 } else { 479 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 480 "SIOCGIFDSTADDR: %.*s: %s", 481 (int)sizeof(ifrdstaddr.ifr_name), 482 ifrdstaddr.ifr_name, 483 pcap_strerror(errno)); 484 ret = -1; 485 break; 486 } 487 } else { 488 dstaddr = &ifrdstaddr.ifr_dstaddr; 489 dstaddr_size = SA_LEN(dstaddr); 490 } 491 } else { 492 /* 493 * Not a point-to-point interface, so no destination 494 * address. 495 */ 496 dstaddr = NULL; 497 dstaddr_size = 0; 498 } 499 500 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 501 /* 502 * If this entry has a colon followed by a number at 503 * the end, it's a logical interface. Those are just 504 * the way you assign multiple IP addresses to a real 505 * interface, so an entry for a logical interface should 506 * be treated like the entry for the real interface; 507 * we do that by stripping off the ":" and the number. 508 */ 509 p = strchr(ifrp->ifr_name, ':'); 510 if (p != NULL) { 511 /* 512 * We have a ":"; is it followed by a number? 513 */ 514 q = p + 1; 515 while (isdigit((unsigned char)*q)) 516 q++; 517 if (*q == '\0') { 518 /* 519 * All digits after the ":" until the end. 520 * Strip off the ":" and everything after 521 * it. 522 */ 523 *p = '\0'; 524 } 525 } 526 #endif 527 528 /* 529 * Add information for this address to the list. 530 */ 531 if (add_addr_to_iflist(&devlist, ifrp->ifr_name, 532 ifrflags.ifr_flags, &ifrp->ifr_addr, 533 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size, 534 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 535 errbuf) < 0) { 536 ret = -1; 537 break; 538 } 539 } 540 free(buf); 541 542 #ifdef HAVE_PROC_NET_DEV 543 if (ret != -1) { 544 /* 545 * We haven't had any errors yet; now read "/proc/net/dev", 546 * and add to the list of interfaces all interfaces listed 547 * there that we don't already have, because, on Linux, 548 * SIOCGIFCONF reports only interfaces with IPv4 addresses, 549 * so you need to read "/proc/net/dev" to get the names of 550 * the rest of the interfaces. 551 */ 552 ret = scan_proc_net_dev(&devlist, fd, errbuf); 553 } 554 #endif 555 (void)close(fd); 556 557 if (ret != -1) { 558 /* 559 * We haven't had any errors yet; do any platform-specific 560 * operations to add devices. 561 */ 562 if (pcap_platform_finddevs(&devlist, errbuf) < 0) 563 ret = -1; 564 } 565 566 if (ret == -1) { 567 /* 568 * We had an error; free the list we've been constructing. 569 */ 570 if (devlist != NULL) { 571 pcap_freealldevs(devlist); 572 devlist = NULL; 573 } 574 } 575 576 *alldevsp = devlist; 577 return (ret); 578 } 579