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 47 struct mbuf; /* Squelch compiler warnings on some platforms for */ 48 struct rtentry; /* declarations in <net/if.h> */ 49 #include <net/if.h> 50 #include <netinet/in.h> 51 52 #include <ctype.h> 53 #include <errno.h> 54 #include <memory.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.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_SOCKADDR_SA_LEN 93 #define SA_LEN(addr) ((addr)->sa_len) 94 #else /* HAVE_SOCKADDR_SA_LEN */ 95 #define SA_LEN(addr) (sizeof (struct sockaddr)) 96 #endif /* HAVE_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 */ 134 int 135 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf, 136 int (*check_usable)(const char *)) 137 { 138 pcap_if_t *devlist = NULL; 139 register int fd; 140 register struct ifreq *ifrp, *ifend, *ifnext; 141 size_t n; 142 struct ifconf ifc; 143 char *buf = NULL; 144 unsigned buf_size; 145 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 146 char *p, *q; 147 #endif 148 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 149 struct sockaddr *netmask, *broadaddr, *dstaddr; 150 size_t netmask_size, broadaddr_size, dstaddr_size; 151 int ret = 0; 152 153 /* 154 * Create a socket from which to fetch the list of interfaces. 155 */ 156 fd = socket(AF_INET, SOCK_DGRAM, 0); 157 if (fd < 0) { 158 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 159 "socket: %s", pcap_strerror(errno)); 160 return (-1); 161 } 162 163 /* 164 * Start with an 8K buffer, and keep growing the buffer until 165 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 166 * bytes left over in the buffer or we fail to get the 167 * interface list for some reason other than EINVAL (which is 168 * presumed here to mean "buffer is too small"). 169 */ 170 buf_size = 8192; 171 for (;;) { 172 buf = malloc(buf_size); 173 if (buf == NULL) { 174 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 175 "malloc: %s", pcap_strerror(errno)); 176 (void)close(fd); 177 return (-1); 178 } 179 180 ifc.ifc_len = buf_size; 181 ifc.ifc_buf = buf; 182 memset(buf, 0, buf_size); 183 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 184 && errno != EINVAL) { 185 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 186 "SIOCGIFCONF: %s", pcap_strerror(errno)); 187 (void)close(fd); 188 free(buf); 189 return (-1); 190 } 191 if (ifc.ifc_len < buf_size && 192 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 193 break; 194 free(buf); 195 buf_size *= 2; 196 } 197 198 ifrp = (struct ifreq *)buf; 199 ifend = (struct ifreq *)(buf + ifc.ifc_len); 200 201 for (; ifrp < ifend; ifrp = ifnext) { 202 /* 203 * XXX - what if this isn't an IPv4 address? Can 204 * we still get the netmask, etc. with ioctls on 205 * an IPv4 socket? 206 * 207 * The answer is probably platform-dependent, and 208 * if the answer is "no" on more than one platform, 209 * the way you work around it is probably platform- 210 * dependent as well. 211 */ 212 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 213 if (n < sizeof(*ifrp)) 214 ifnext = ifrp + 1; 215 else 216 ifnext = (struct ifreq *)((char *)ifrp + n); 217 218 /* 219 * XXX - The 32-bit compatibility layer for Linux on IA-64 220 * is slightly broken. It correctly converts the structures 221 * to and from kernel land from 64 bit to 32 bit but 222 * doesn't update ifc.ifc_len, leaving it larger than the 223 * amount really used. This means we read off the end 224 * of the buffer and encounter an interface with an 225 * "empty" name. Since this is highly unlikely to ever 226 * occur in a valid case we can just finish looking for 227 * interfaces if we see an empty name. 228 */ 229 if (!(*ifrp->ifr_name)) 230 break; 231 232 /* 233 * Skip entries that begin with "dummy". 234 * XXX - what are these? Is this Linux-specific? 235 * Are there platforms on which we shouldn't do this? 236 */ 237 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 238 continue; 239 240 /* 241 * Can we capture on this device? 242 */ 243 if (!(*check_usable)(ifrp->ifr_name)) { 244 /* 245 * No. 246 */ 247 continue; 248 } 249 250 /* 251 * Get the flags for this interface. 252 */ 253 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 254 sizeof(ifrflags.ifr_name)); 255 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 256 if (errno == ENXIO) 257 continue; 258 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 259 "SIOCGIFFLAGS: %.*s: %s", 260 (int)sizeof(ifrflags.ifr_name), 261 ifrflags.ifr_name, 262 pcap_strerror(errno)); 263 ret = -1; 264 break; 265 } 266 267 /* 268 * Get the netmask for this address on this interface. 269 */ 270 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 271 sizeof(ifrnetmask.ifr_name)); 272 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 273 sizeof(ifrnetmask.ifr_addr)); 274 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 275 if (errno == EADDRNOTAVAIL) { 276 /* 277 * Not available. 278 */ 279 netmask = NULL; 280 netmask_size = 0; 281 } else { 282 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 283 "SIOCGIFNETMASK: %.*s: %s", 284 (int)sizeof(ifrnetmask.ifr_name), 285 ifrnetmask.ifr_name, 286 pcap_strerror(errno)); 287 ret = -1; 288 break; 289 } 290 } else { 291 netmask = &ifrnetmask.ifr_addr; 292 netmask_size = SA_LEN(netmask); 293 } 294 295 /* 296 * Get the broadcast address for this address on this 297 * interface (if any). 298 */ 299 if (ifrflags.ifr_flags & IFF_BROADCAST) { 300 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 301 sizeof(ifrbroadaddr.ifr_name)); 302 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 303 sizeof(ifrbroadaddr.ifr_addr)); 304 if (ioctl(fd, SIOCGIFBRDADDR, 305 (char *)&ifrbroadaddr) < 0) { 306 if (errno == EADDRNOTAVAIL) { 307 /* 308 * Not available. 309 */ 310 broadaddr = NULL; 311 broadaddr_size = 0; 312 } else { 313 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 314 "SIOCGIFBRDADDR: %.*s: %s", 315 (int)sizeof(ifrbroadaddr.ifr_name), 316 ifrbroadaddr.ifr_name, 317 pcap_strerror(errno)); 318 ret = -1; 319 break; 320 } 321 } else { 322 broadaddr = &ifrbroadaddr.ifr_broadaddr; 323 broadaddr_size = SA_LEN(broadaddr); 324 } 325 } else { 326 /* 327 * Not a broadcast interface, so no broadcast 328 * address. 329 */ 330 broadaddr = NULL; 331 broadaddr_size = 0; 332 } 333 334 /* 335 * Get the destination address for this address on this 336 * interface (if any). 337 */ 338 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 339 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 340 sizeof(ifrdstaddr.ifr_name)); 341 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 342 sizeof(ifrdstaddr.ifr_addr)); 343 if (ioctl(fd, SIOCGIFDSTADDR, 344 (char *)&ifrdstaddr) < 0) { 345 if (errno == EADDRNOTAVAIL) { 346 /* 347 * Not available. 348 */ 349 dstaddr = NULL; 350 dstaddr_size = 0; 351 } else { 352 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 353 "SIOCGIFDSTADDR: %.*s: %s", 354 (int)sizeof(ifrdstaddr.ifr_name), 355 ifrdstaddr.ifr_name, 356 pcap_strerror(errno)); 357 ret = -1; 358 break; 359 } 360 } else { 361 dstaddr = &ifrdstaddr.ifr_dstaddr; 362 dstaddr_size = SA_LEN(dstaddr); 363 } 364 } else { 365 /* 366 * Not a point-to-point interface, so no destination 367 * address. 368 */ 369 dstaddr = NULL; 370 dstaddr_size = 0; 371 } 372 373 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 374 /* 375 * If this entry has a colon followed by a number at 376 * the end, it's a logical interface. Those are just 377 * the way you assign multiple IP addresses to a real 378 * interface, so an entry for a logical interface should 379 * be treated like the entry for the real interface; 380 * we do that by stripping off the ":" and the number. 381 */ 382 p = strchr(ifrp->ifr_name, ':'); 383 if (p != NULL) { 384 /* 385 * We have a ":"; is it followed by a number? 386 */ 387 q = p + 1; 388 while (isdigit((unsigned char)*q)) 389 q++; 390 if (*q == '\0') { 391 /* 392 * All digits after the ":" until the end. 393 * Strip off the ":" and everything after 394 * it. 395 */ 396 *p = '\0'; 397 } 398 } 399 #endif 400 401 /* 402 * Add information for this address to the list. 403 */ 404 if (add_addr_to_iflist(&devlist, ifrp->ifr_name, 405 if_flags_to_pcap_flags(ifrp->ifr_name, ifrflags.ifr_flags), 406 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr), 407 netmask, netmask_size, broadaddr, broadaddr_size, 408 dstaddr, dstaddr_size, errbuf) < 0) { 409 ret = -1; 410 break; 411 } 412 } 413 free(buf); 414 (void)close(fd); 415 416 if (ret == -1) { 417 /* 418 * We had an error; free the list we've been constructing. 419 */ 420 if (devlist != NULL) { 421 pcap_freealldevs(devlist); 422 devlist = NULL; 423 } 424 } 425 426 *alldevsp = devlist; 427 return (ret); 428 } 429
