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 #ifdef HAVE_LIMITS_H 61 #include <limits.h> 62 #else 63 #define INT_MAX 2147483647 64 #endif 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_STRUCT_SOCKADDR_SA_LEN 99 #define SA_LEN(addr) ((addr)->sa_len) 100 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 101 #define SA_LEN(addr) (sizeof (struct sockaddr)) 102 #endif /* HAVE_STRUCT_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 /* 127 * Get a list of all interfaces that are up and that we can open. 128 * Returns -1 on error, 0 otherwise. 129 * The list, as returned through "alldevsp", may be null if no interfaces 130 * were up and could be opened. 131 * 132 * This is the implementation used on platforms that have SIOCGIFCONF but 133 * don't have any other mechanism for getting a list of interfaces. 134 * 135 * XXX - or platforms that have other, better mechanisms but for which 136 * we don't yet have code to use that mechanism; I think there's a better 137 * way on Linux, for example, but if that better way is "getifaddrs()", 138 * we already have that. 139 */ 140 int 141 pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, 142 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 143 { 144 register int fd; 145 register struct ifreq *ifrp, *ifend, *ifnext; 146 size_t n; 147 struct ifconf ifc; 148 char *buf = NULL; 149 unsigned buf_size; 150 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 151 char *p, *q; 152 #endif 153 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 154 struct sockaddr *netmask, *broadaddr, *dstaddr; 155 size_t netmask_size, broadaddr_size, dstaddr_size; 156 int ret = 0; 157 158 /* 159 * Create a socket from which to fetch the list of interfaces. 160 */ 161 fd = socket(AF_INET, SOCK_DGRAM, 0); 162 if (fd < 0) { 163 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 164 errno, "socket"); 165 return (-1); 166 } 167 168 /* 169 * Start with an 8K buffer, and keep growing the buffer until 170 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 171 * bytes left over in the buffer or we fail to get the 172 * interface list for some reason other than EINVAL (which is 173 * presumed here to mean "buffer is too small"). 174 */ 175 buf_size = 8192; 176 for (;;) { 177 /* 178 * Don't let the buffer size get bigger than INT_MAX. 179 */ 180 if (buf_size > INT_MAX) { 181 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 182 "interface information requires more than %u bytes", 183 INT_MAX); 184 (void)close(fd); 185 return (-1); 186 } 187 buf = malloc(buf_size); 188 if (buf == NULL) { 189 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 190 errno, "malloc"); 191 (void)close(fd); 192 return (-1); 193 } 194 195 ifc.ifc_len = buf_size; 196 ifc.ifc_buf = buf; 197 memset(buf, 0, buf_size); 198 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 199 && errno != EINVAL) { 200 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 201 errno, "SIOCGIFCONF"); 202 (void)close(fd); 203 free(buf); 204 return (-1); 205 } 206 if (ifc.ifc_len < (int)buf_size && 207 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 208 break; 209 free(buf); 210 buf_size *= 2; 211 } 212 213 ifrp = (struct ifreq *)buf; 214 ifend = (struct ifreq *)(buf + ifc.ifc_len); 215 216 for (; ifrp < ifend; ifrp = ifnext) { 217 /* 218 * XXX - what if this isn't an IPv4 address? Can 219 * we still get the netmask, etc. with ioctls on 220 * an IPv4 socket? 221 * 222 * The answer is probably platform-dependent, and 223 * if the answer is "no" on more than one platform, 224 * the way you work around it is probably platform- 225 * dependent as well. 226 */ 227 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 228 if (n < sizeof(*ifrp)) 229 ifnext = ifrp + 1; 230 else 231 ifnext = (struct ifreq *)((char *)ifrp + n); 232 233 /* 234 * XXX - The 32-bit compatibility layer for Linux on IA-64 235 * is slightly broken. It correctly converts the structures 236 * to and from kernel land from 64 bit to 32 bit but 237 * doesn't update ifc.ifc_len, leaving it larger than the 238 * amount really used. This means we read off the end 239 * of the buffer and encounter an interface with an 240 * "empty" name. Since this is highly unlikely to ever 241 * occur in a valid case we can just finish looking for 242 * interfaces if we see an empty name. 243 */ 244 if (!(*ifrp->ifr_name)) 245 break; 246 247 /* 248 * Skip entries that begin with "dummy". 249 * XXX - what are these? Is this Linux-specific? 250 * Are there platforms on which we shouldn't do this? 251 */ 252 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 253 continue; 254 255 /* 256 * Can we capture on this device? 257 */ 258 if (!(*check_usable)(ifrp->ifr_name)) { 259 /* 260 * No. 261 */ 262 continue; 263 } 264 265 /* 266 * Get the flags for this interface. 267 */ 268 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 269 sizeof(ifrflags.ifr_name)); 270 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 271 if (errno == ENXIO) 272 continue; 273 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 274 errno, "SIOCGIFFLAGS: %.*s", 275 (int)sizeof(ifrflags.ifr_name), 276 ifrflags.ifr_name); 277 ret = -1; 278 break; 279 } 280 281 /* 282 * Get the netmask for this address on this interface. 283 */ 284 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 285 sizeof(ifrnetmask.ifr_name)); 286 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 287 sizeof(ifrnetmask.ifr_addr)); 288 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 289 if (errno == EADDRNOTAVAIL) { 290 /* 291 * Not available. 292 */ 293 netmask = NULL; 294 netmask_size = 0; 295 } else { 296 pcap_fmt_errmsg_for_errno(errbuf, 297 PCAP_ERRBUF_SIZE, errno, 298 "SIOCGIFNETMASK: %.*s", 299 (int)sizeof(ifrnetmask.ifr_name), 300 ifrnetmask.ifr_name); 301 ret = -1; 302 break; 303 } 304 } else { 305 netmask = &ifrnetmask.ifr_addr; 306 netmask_size = SA_LEN(netmask); 307 } 308 309 /* 310 * Get the broadcast address for this address on this 311 * interface (if any). 312 */ 313 if (ifrflags.ifr_flags & IFF_BROADCAST) { 314 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 315 sizeof(ifrbroadaddr.ifr_name)); 316 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 317 sizeof(ifrbroadaddr.ifr_addr)); 318 if (ioctl(fd, SIOCGIFBRDADDR, 319 (char *)&ifrbroadaddr) < 0) { 320 if (errno == EADDRNOTAVAIL) { 321 /* 322 * Not available. 323 */ 324 broadaddr = NULL; 325 broadaddr_size = 0; 326 } else { 327 pcap_fmt_errmsg_for_errno(errbuf, 328 PCAP_ERRBUF_SIZE, errno, 329 "SIOCGIFBRDADDR: %.*s", 330 (int)sizeof(ifrbroadaddr.ifr_name), 331 ifrbroadaddr.ifr_name); 332 ret = -1; 333 break; 334 } 335 } else { 336 broadaddr = &ifrbroadaddr.ifr_broadaddr; 337 broadaddr_size = SA_LEN(broadaddr); 338 } 339 } else { 340 /* 341 * Not a broadcast interface, so no broadcast 342 * address. 343 */ 344 broadaddr = NULL; 345 broadaddr_size = 0; 346 } 347 348 /* 349 * Get the destination address for this address on this 350 * interface (if any). 351 */ 352 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 353 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 354 sizeof(ifrdstaddr.ifr_name)); 355 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 356 sizeof(ifrdstaddr.ifr_addr)); 357 if (ioctl(fd, SIOCGIFDSTADDR, 358 (char *)&ifrdstaddr) < 0) { 359 if (errno == EADDRNOTAVAIL) { 360 /* 361 * Not available. 362 */ 363 dstaddr = NULL; 364 dstaddr_size = 0; 365 } else { 366 pcap_fmt_errmsg_for_errno(errbuf, 367 PCAP_ERRBUF_SIZE, errno, 368 "SIOCGIFDSTADDR: %.*s", 369 (int)sizeof(ifrdstaddr.ifr_name), 370 ifrdstaddr.ifr_name); 371 ret = -1; 372 break; 373 } 374 } else { 375 dstaddr = &ifrdstaddr.ifr_dstaddr; 376 dstaddr_size = SA_LEN(dstaddr); 377 } 378 } else { 379 /* 380 * Not a point-to-point interface, so no destination 381 * address. 382 */ 383 dstaddr = NULL; 384 dstaddr_size = 0; 385 } 386 387 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 388 /* 389 * If this entry has a colon followed by a number at 390 * the end, it's a logical interface. Those are just 391 * the way you assign multiple IP addresses to a real 392 * interface, so an entry for a logical interface should 393 * be treated like the entry for the real interface; 394 * we do that by stripping off the ":" and the number. 395 */ 396 p = strchr(ifrp->ifr_name, ':'); 397 if (p != NULL) { 398 /* 399 * We have a ":"; is it followed by a number? 400 */ 401 q = p + 1; 402 while (isdigit((unsigned char)*q)) 403 q++; 404 if (*q == '\0') { 405 /* 406 * All digits after the ":" until the end. 407 * Strip off the ":" and everything after 408 * it. 409 */ 410 *p = '\0'; 411 } 412 } 413 #endif 414 415 /* 416 * Add information for this address to the list. 417 */ 418 if (add_addr_to_if(devlistp, ifrp->ifr_name, 419 ifrflags.ifr_flags, get_flags_func, 420 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr), 421 netmask, netmask_size, broadaddr, broadaddr_size, 422 dstaddr, dstaddr_size, errbuf) < 0) { 423 ret = -1; 424 break; 425 } 426 } 427 free(buf); 428 (void)close(fd); 429 430 return (ret); 431 } 432