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