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 #include <config.h> 36 37 #include <sys/param.h> 38 #include <sys/ioctl.h> 39 #include <sys/socket.h> 40 #ifdef HAVE_SYS_SOCKIO_H 41 #include <sys/sockio.h> 42 #endif 43 #include <sys/time.h> /* concession to AIX */ 44 45 struct mbuf; /* Squelch compiler warnings on some platforms for */ 46 struct rtentry; /* declarations in <net/if.h> */ 47 #include <net/if.h> 48 #include <netinet/in.h> 49 50 #include <errno.h> 51 #include <memory.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 #include <limits.h> 57 58 #include "pcap-int.h" 59 60 #ifdef HAVE_OS_PROTO_H 61 #include "os-proto.h" 62 #endif 63 64 /* 65 * This is fun. 66 * 67 * In older BSD systems, socket addresses were fixed-length, and 68 * "sizeof (struct sockaddr)" gave the size of the structure. 69 * All addresses fit within a "struct sockaddr". 70 * 71 * In newer BSD systems, the socket address is variable-length, and 72 * there's an "sa_len" field giving the length of the structure; 73 * this allows socket addresses to be longer than 2 bytes of family 74 * and 14 bytes of data. 75 * 76 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 77 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 78 * than "struct sockaddr"), and some use the new BSD scheme. 79 * 80 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 81 * macro that determines the size based on the address family. Other 82 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 83 * but not in the final version). 84 * 85 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have 86 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the 87 * address in an entry returned by SIOCGIFCONF. 88 * 89 * OSes that use this file are: 90 * - AIX 7 (SA_LEN() is not defined, HAVE_STRUCT_SOCKADDR_SA_LEN is defined) 91 * - HP-UX 11 (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined) 92 */ 93 #ifndef SA_LEN 94 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN 95 #define SA_LEN(addr) ((addr)->sa_len) 96 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 97 #define SA_LEN(addr) (sizeof (struct sockaddr)) 98 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 99 #endif /* SA_LEN */ 100 101 /* 102 * This is also fun. 103 * 104 * There is no ioctl that returns the amount of space required for all 105 * the data that SIOCGIFCONF could return, and if a buffer is supplied 106 * that's not large enough for all the data SIOCGIFCONF could return, 107 * on at least some platforms it just returns the data that'd fit with 108 * no indication that there wasn't enough room for all the data, much 109 * less an indication of how much more room is required. 110 * 111 * The only way to ensure that we got all the data is to pass a buffer 112 * large enough that the amount of space in the buffer *not* filled in 113 * is greater than the largest possible entry. 114 * 115 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption 116 * that no address is more than 255 bytes (on systems where the "sa_len" 117 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the 118 * case, and addresses are unlikely to be bigger than that in any case). 119 */ 120 #define MAX_SA_LEN 255 121 122 /* 123 * Get a list of all interfaces that are up and that we can open. 124 * Returns -1 on error, 0 otherwise. 125 * The list, as returned through "alldevsp", may be null if no interfaces 126 * were up and could be opened. 127 * 128 * This is the implementation used on platforms that have SIOCGIFCONF but 129 * don't have any other mechanism for getting a list of interfaces. 130 * 131 * XXX - or platforms that have other, better mechanisms but for which 132 * we don't yet have code to use that mechanism; I think there's a better 133 * way on Linux, for example, but if that better way is "getifaddrs()", 134 * we already have that. 135 */ 136 int 137 pcapint_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, 138 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 139 { 140 register int fd; 141 register struct ifreq *ifrp, *ifend, *ifnext; 142 size_t n; 143 struct ifconf ifc; 144 char *buf = NULL; 145 unsigned buf_size; 146 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 147 char *p, *q; 148 #endif 149 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 150 struct sockaddr *netmask, *broadaddr, *dstaddr; 151 size_t netmask_size, broadaddr_size, dstaddr_size; 152 int ret = 0; 153 154 /* 155 * Create a socket from which to fetch the list of interfaces. 156 */ 157 fd = socket(AF_INET, SOCK_DGRAM, 0); 158 if (fd < 0) { 159 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 160 errno, "socket"); 161 return (-1); 162 } 163 164 /* 165 * Start with an 8K buffer, and keep growing the buffer until 166 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 167 * bytes left over in the buffer or we fail to get the 168 * interface list for some reason other than EINVAL (which is 169 * presumed here to mean "buffer is too small"). 170 */ 171 buf_size = 8192; 172 for (;;) { 173 /* 174 * Don't let the buffer size get bigger than INT_MAX. 175 */ 176 if (buf_size > INT_MAX) { 177 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 178 "interface information requires more than %u bytes", 179 INT_MAX); 180 (void)close(fd); 181 return (-1); 182 } 183 buf = malloc(buf_size); 184 if (buf == NULL) { 185 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 186 errno, "malloc"); 187 (void)close(fd); 188 return (-1); 189 } 190 191 ifc.ifc_len = buf_size; 192 ifc.ifc_buf = buf; 193 memset(buf, 0, buf_size); 194 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 195 && errno != EINVAL) { 196 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 197 errno, "SIOCGIFCONF"); 198 (void)close(fd); 199 free(buf); 200 return (-1); 201 } 202 if (ifc.ifc_len < (int)buf_size && 203 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 204 break; 205 free(buf); 206 buf_size *= 2; 207 } 208 209 ifrp = (struct ifreq *)buf; 210 ifend = (struct ifreq *)(buf + ifc.ifc_len); 211 212 for (; ifrp < ifend; ifrp = ifnext) { 213 /* 214 * XXX - what if this isn't an IPv4 address? Can 215 * we still get the netmask, etc. with ioctls on 216 * an IPv4 socket? 217 * 218 * The answer is probably platform-dependent, and 219 * if the answer is "no" on more than one platform, 220 * the way you work around it is probably platform- 221 * dependent as well. 222 */ 223 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 224 if (n < sizeof(*ifrp)) 225 ifnext = ifrp + 1; 226 else 227 ifnext = (struct ifreq *)((char *)ifrp + n); 228 229 /* 230 * XXX - The 32-bit compatibility layer for Linux on IA-64 231 * is slightly broken. It correctly converts the structures 232 * to and from kernel land from 64 bit to 32 bit but 233 * doesn't update ifc.ifc_len, leaving it larger than the 234 * amount really used. This means we read off the end 235 * of the buffer and encounter an interface with an 236 * "empty" name. Since this is highly unlikely to ever 237 * occur in a valid case we can just finish looking for 238 * interfaces if we see an empty name. 239 */ 240 if (!(*ifrp->ifr_name)) 241 break; 242 243 /* 244 * Skip entries that begin with "dummy". 245 * XXX - what are these? Is this Linux-specific? 246 * Are there platforms on which we shouldn't do this? 247 */ 248 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 249 continue; 250 251 /* 252 * Can we capture on this device? 253 */ 254 if (!(*check_usable)(ifrp->ifr_name)) { 255 /* 256 * No. 257 */ 258 continue; 259 } 260 261 /* 262 * Get the flags for this interface. 263 */ 264 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 265 sizeof(ifrflags.ifr_name)); 266 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 267 if (errno == ENXIO) 268 continue; 269 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 270 errno, "SIOCGIFFLAGS: %.*s", 271 (int)sizeof(ifrflags.ifr_name), 272 ifrflags.ifr_name); 273 ret = -1; 274 break; 275 } 276 277 /* 278 * Get the netmask for this address on this interface. 279 */ 280 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 281 sizeof(ifrnetmask.ifr_name)); 282 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 283 sizeof(ifrnetmask.ifr_addr)); 284 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 285 if (errno == EADDRNOTAVAIL) { 286 /* 287 * Not available. 288 */ 289 netmask = NULL; 290 netmask_size = 0; 291 } else { 292 pcapint_fmt_errmsg_for_errno(errbuf, 293 PCAP_ERRBUF_SIZE, errno, 294 "SIOCGIFNETMASK: %.*s", 295 (int)sizeof(ifrnetmask.ifr_name), 296 ifrnetmask.ifr_name); 297 ret = -1; 298 break; 299 } 300 } else { 301 netmask = &ifrnetmask.ifr_addr; 302 netmask_size = SA_LEN(netmask); 303 } 304 305 /* 306 * Get the broadcast address for this address on this 307 * interface (if any). 308 */ 309 if (ifrflags.ifr_flags & IFF_BROADCAST) { 310 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 311 sizeof(ifrbroadaddr.ifr_name)); 312 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 313 sizeof(ifrbroadaddr.ifr_addr)); 314 if (ioctl(fd, SIOCGIFBRDADDR, 315 (char *)&ifrbroadaddr) < 0) { 316 if (errno == EADDRNOTAVAIL) { 317 /* 318 * Not available. 319 */ 320 broadaddr = NULL; 321 broadaddr_size = 0; 322 } else { 323 pcapint_fmt_errmsg_for_errno(errbuf, 324 PCAP_ERRBUF_SIZE, errno, 325 "SIOCGIFBRDADDR: %.*s", 326 (int)sizeof(ifrbroadaddr.ifr_name), 327 ifrbroadaddr.ifr_name); 328 ret = -1; 329 break; 330 } 331 } else { 332 broadaddr = &ifrbroadaddr.ifr_broadaddr; 333 broadaddr_size = SA_LEN(broadaddr); 334 } 335 } else { 336 /* 337 * Not a broadcast interface, so no broadcast 338 * address. 339 */ 340 broadaddr = NULL; 341 broadaddr_size = 0; 342 } 343 344 /* 345 * Get the destination address for this address on this 346 * interface (if any). 347 */ 348 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 349 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 350 sizeof(ifrdstaddr.ifr_name)); 351 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 352 sizeof(ifrdstaddr.ifr_addr)); 353 if (ioctl(fd, SIOCGIFDSTADDR, 354 (char *)&ifrdstaddr) < 0) { 355 if (errno == EADDRNOTAVAIL) { 356 /* 357 * Not available. 358 */ 359 dstaddr = NULL; 360 dstaddr_size = 0; 361 } else { 362 pcapint_fmt_errmsg_for_errno(errbuf, 363 PCAP_ERRBUF_SIZE, errno, 364 "SIOCGIFDSTADDR: %.*s", 365 (int)sizeof(ifrdstaddr.ifr_name), 366 ifrdstaddr.ifr_name); 367 ret = -1; 368 break; 369 } 370 } else { 371 dstaddr = &ifrdstaddr.ifr_dstaddr; 372 dstaddr_size = SA_LEN(dstaddr); 373 } 374 } else { 375 /* 376 * Not a point-to-point interface, so no destination 377 * address. 378 */ 379 dstaddr = NULL; 380 dstaddr_size = 0; 381 } 382 383 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 384 /* 385 * If this entry has a colon followed by a number at 386 * the end, it's a logical interface. Those are just 387 * the way you assign multiple IP addresses to a real 388 * interface, so an entry for a logical interface should 389 * be treated like the entry for the real interface; 390 * we do that by stripping off the ":" and the number. 391 */ 392 p = strchr(ifrp->ifr_name, ':'); 393 if (p != NULL) { 394 /* 395 * We have a ":"; is it followed by a number? 396 */ 397 q = p + 1; 398 while (PCAP_ISDIGIT(*q)) 399 q++; 400 if (*q == '\0') { 401 /* 402 * All digits after the ":" until the end. 403 * Strip off the ":" and everything after 404 * it. 405 */ 406 *p = '\0'; 407 } 408 } 409 #endif 410 411 /* 412 * Add information for this address to the list. 413 */ 414 if (pcapint_add_addr_to_if(devlistp, ifrp->ifr_name, 415 ifrflags.ifr_flags, get_flags_func, 416 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr), 417 netmask, netmask_size, broadaddr, broadaddr_size, 418 dstaddr, dstaddr_size, errbuf) < 0) { 419 ret = -1; 420 break; 421 } 422 } 423 free(buf); 424 (void)close(fd); 425 426 return (ret); 427 } 428