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 1.12 2008-08-06 07:34:09 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/ioctl.h> 46 #include <sys/socket.h> 47 #ifdef HAVE_SYS_SOCKIO_H 48 #include <sys/sockio.h> 49 #endif 50 #include <sys/time.h> /* concession to AIX */ 51 52 struct mbuf; /* Squelch compiler warnings on some platforms for */ 53 struct rtentry; /* declarations in <net/if.h> */ 54 #include <net/if.h> 55 #include <netinet/in.h> 56 57 #include <ctype.h> 58 #include <errno.h> 59 #include <memory.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 65 #include "pcap-int.h" 66 67 #ifdef HAVE_OS_PROTO_H 68 #include "os-proto.h" 69 #endif 70 71 /* 72 * This is fun. 73 * 74 * In older BSD systems, socket addresses were fixed-length, and 75 * "sizeof (struct sockaddr)" gave the size of the structure. 76 * All addresses fit within a "struct sockaddr". 77 * 78 * In newer BSD systems, the socket address is variable-length, and 79 * there's an "sa_len" field giving the length of the structure; 80 * this allows socket addresses to be longer than 2 bytes of family 81 * and 14 bytes of data. 82 * 83 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 84 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 85 * than "struct sockaddr"), and some use the new BSD scheme. 86 * 87 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 88 * macro that determines the size based on the address family. Other 89 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 90 * but not in the final version). 91 * 92 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have 93 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the 94 * address in an entry returned by SIOCGIFCONF. 95 */ 96 #ifndef SA_LEN 97 #ifdef HAVE_SOCKADDR_SA_LEN 98 #define SA_LEN(addr) ((addr)->sa_len) 99 #else /* HAVE_SOCKADDR_SA_LEN */ 100 #define SA_LEN(addr) (sizeof (struct sockaddr)) 101 #endif /* HAVE_SOCKADDR_SA_LEN */ 102 #endif /* SA_LEN */ 103 104 /* 105 * This is also fun. 106 * 107 * There is no ioctl that returns the amount of space required for all 108 * the data that SIOCGIFCONF could return, and if a buffer is supplied 109 * that's not large enough for all the data SIOCGIFCONF could return, 110 * on at least some platforms it just returns the data that'd fit with 111 * no indication that there wasn't enough room for all the data, much 112 * less an indication of how much more room is required. 113 * 114 * The only way to ensure that we got all the data is to pass a buffer 115 * large enough that the amount of space in the buffer *not* filled in 116 * is greater than the largest possible entry. 117 * 118 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption 119 * that no address is more than 255 bytes (on systems where the "sa_len" 120 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the 121 * case, and addresses are unlikely to be bigger than that in any case). 122 */ 123 #define MAX_SA_LEN 255 124 125 /* 126 * Get a list of all interfaces that are up and that we can open. 127 * Returns -1 on error, 0 otherwise. 128 * The list, as returned through "alldevsp", may be null if no interfaces 129 * were up and could be opened. 130 * 131 * This is the implementation used on platforms that have SIOCGIFCONF but 132 * don't have any other mechanism for getting a list of interfaces. 133 * 134 * XXX - or platforms that have other, better mechanisms but for which 135 * we don't yet have code to use that mechanism; I think there's a better 136 * way on Linux, for example, but if that better way is "getifaddrs()", 137 * we already have that. 138 */ 139 int 140 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf) 141 { 142 pcap_if_t *devlist = NULL; 143 register int fd; 144 register struct ifreq *ifrp, *ifend, *ifnext; 145 int n; 146 struct ifconf ifc; 147 char *buf = NULL; 148 unsigned buf_size; 149 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 150 char *p, *q; 151 #endif 152 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 153 struct sockaddr *netmask, *broadaddr, *dstaddr; 154 size_t netmask_size, broadaddr_size, dstaddr_size; 155 int ret = 0; 156 157 /* 158 * Create a socket from which to fetch the list of interfaces. 159 */ 160 fd = socket(AF_INET, SOCK_DGRAM, 0); 161 if (fd < 0) { 162 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 163 "socket: %s", pcap_strerror(errno)); 164 return (-1); 165 } 166 167 /* 168 * Start with an 8K buffer, and keep growing the buffer until 169 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 170 * bytes left over in the buffer or we fail to get the 171 * interface list for some reason other than EINVAL (which is 172 * presumed here to mean "buffer is too small"). 173 */ 174 buf_size = 8192; 175 for (;;) { 176 buf = malloc(buf_size); 177 if (buf == NULL) { 178 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 179 "malloc: %s", pcap_strerror(errno)); 180 (void)close(fd); 181 return (-1); 182 } 183 184 ifc.ifc_len = buf_size; 185 ifc.ifc_buf = buf; 186 memset(buf, 0, buf_size); 187 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 188 && errno != EINVAL) { 189 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 190 "SIOCGIFCONF: %s", pcap_strerror(errno)); 191 (void)close(fd); 192 free(buf); 193 return (-1); 194 } 195 if (ifc.ifc_len < buf_size && 196 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 197 break; 198 free(buf); 199 buf_size *= 2; 200 } 201 202 ifrp = (struct ifreq *)buf; 203 ifend = (struct ifreq *)(buf + ifc.ifc_len); 204 205 for (; ifrp < ifend; ifrp = ifnext) { 206 /* 207 * XXX - what if this isn't an IPv4 address? Can 208 * we still get the netmask, etc. with ioctls on 209 * an IPv4 socket? 210 * 211 * The answer is probably platform-dependent, and 212 * if the answer is "no" on more than one platform, 213 * the way you work around it is probably platform- 214 * dependent as well. 215 */ 216 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 217 if (n < sizeof(*ifrp)) 218 ifnext = ifrp + 1; 219 else 220 ifnext = (struct ifreq *)((char *)ifrp + n); 221 222 /* 223 * XXX - The 32-bit compatibility layer for Linux on IA-64 224 * is slightly broken. It correctly converts the structures 225 * to and from kernel land from 64 bit to 32 bit but 226 * doesn't update ifc.ifc_len, leaving it larger than the 227 * amount really used. This means we read off the end 228 * of the buffer and encounter an interface with an 229 * "empty" name. Since this is highly unlikely to ever 230 * occur in a valid case we can just finish looking for 231 * interfaces if we see an empty name. 232 */ 233 if (!(*ifrp->ifr_name)) 234 break; 235 236 /* 237 * Skip entries that begin with "dummy". 238 * XXX - what are these? Is this Linux-specific? 239 * Are there platforms on which we shouldn't do this? 240 */ 241 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 242 continue; 243 244 /* 245 * Get the flags for this interface, and skip it if it's 246 * not up. 247 */ 248 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 249 sizeof(ifrflags.ifr_name)); 250 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 251 if (errno == ENXIO) 252 continue; 253 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 254 "SIOCGIFFLAGS: %.*s: %s", 255 (int)sizeof(ifrflags.ifr_name), 256 ifrflags.ifr_name, 257 pcap_strerror(errno)); 258 ret = -1; 259 break; 260 } 261 if (!(ifrflags.ifr_flags & IFF_UP)) 262 continue; 263 264 /* 265 * Get the netmask for this address on this interface. 266 */ 267 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 268 sizeof(ifrnetmask.ifr_name)); 269 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 270 sizeof(ifrnetmask.ifr_addr)); 271 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 272 if (errno == EADDRNOTAVAIL) { 273 /* 274 * Not available. 275 */ 276 netmask = NULL; 277 netmask_size = 0; 278 } else { 279 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 280 "SIOCGIFNETMASK: %.*s: %s", 281 (int)sizeof(ifrnetmask.ifr_name), 282 ifrnetmask.ifr_name, 283 pcap_strerror(errno)); 284 ret = -1; 285 break; 286 } 287 } else { 288 netmask = &ifrnetmask.ifr_addr; 289 netmask_size = SA_LEN(netmask); 290 } 291 292 /* 293 * Get the broadcast address for this address on this 294 * interface (if any). 295 */ 296 if (ifrflags.ifr_flags & IFF_BROADCAST) { 297 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 298 sizeof(ifrbroadaddr.ifr_name)); 299 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 300 sizeof(ifrbroadaddr.ifr_addr)); 301 if (ioctl(fd, SIOCGIFBRDADDR, 302 (char *)&ifrbroadaddr) < 0) { 303 if (errno == EADDRNOTAVAIL) { 304 /* 305 * Not available. 306 */ 307 broadaddr = NULL; 308 broadaddr_size = 0; 309 } else { 310 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 311 "SIOCGIFBRDADDR: %.*s: %s", 312 (int)sizeof(ifrbroadaddr.ifr_name), 313 ifrbroadaddr.ifr_name, 314 pcap_strerror(errno)); 315 ret = -1; 316 break; 317 } 318 } else { 319 broadaddr = &ifrbroadaddr.ifr_broadaddr; 320 broadaddr_size = SA_LEN(broadaddr); 321 } 322 } else { 323 /* 324 * Not a broadcast interface, so no broadcast 325 * address. 326 */ 327 broadaddr = NULL; 328 broadaddr_size = 0; 329 } 330 331 /* 332 * Get the destination address for this address on this 333 * interface (if any). 334 */ 335 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 336 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 337 sizeof(ifrdstaddr.ifr_name)); 338 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 339 sizeof(ifrdstaddr.ifr_addr)); 340 if (ioctl(fd, SIOCGIFDSTADDR, 341 (char *)&ifrdstaddr) < 0) { 342 if (errno == EADDRNOTAVAIL) { 343 /* 344 * Not available. 345 */ 346 dstaddr = NULL; 347 dstaddr_size = 0; 348 } else { 349 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 350 "SIOCGIFDSTADDR: %.*s: %s", 351 (int)sizeof(ifrdstaddr.ifr_name), 352 ifrdstaddr.ifr_name, 353 pcap_strerror(errno)); 354 ret = -1; 355 break; 356 } 357 } else { 358 dstaddr = &ifrdstaddr.ifr_dstaddr; 359 dstaddr_size = SA_LEN(dstaddr); 360 } 361 } else { 362 /* 363 * Not a point-to-point interface, so no destination 364 * address. 365 */ 366 dstaddr = NULL; 367 dstaddr_size = 0; 368 } 369 370 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 371 /* 372 * If this entry has a colon followed by a number at 373 * the end, it's a logical interface. Those are just 374 * the way you assign multiple IP addresses to a real 375 * interface, so an entry for a logical interface should 376 * be treated like the entry for the real interface; 377 * we do that by stripping off the ":" and the number. 378 */ 379 p = strchr(ifrp->ifr_name, ':'); 380 if (p != NULL) { 381 /* 382 * We have a ":"; is it followed by a number? 383 */ 384 q = p + 1; 385 while (isdigit((unsigned char)*q)) 386 q++; 387 if (*q == '\0') { 388 /* 389 * All digits after the ":" until the end. 390 * Strip off the ":" and everything after 391 * it. 392 */ 393 *p = '\0'; 394 } 395 } 396 #endif 397 398 /* 399 * Add information for this address to the list. 400 */ 401 if (add_addr_to_iflist(&devlist, ifrp->ifr_name, 402 ifrflags.ifr_flags, &ifrp->ifr_addr, 403 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size, 404 broadaddr, broadaddr_size, dstaddr, dstaddr_size, 405 errbuf) < 0) { 406 ret = -1; 407 break; 408 } 409 } 410 free(buf); 411 (void)close(fd); 412 413 if (ret == -1) { 414 /* 415 * We had an error; free the list we've been constructing. 416 */ 417 if (devlist != NULL) { 418 pcap_freealldevs(devlist); 419 devlist = NULL; 420 } 421 } 422 423 *alldevsp = devlist; 424 return (ret); 425 } 426