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