1 /* $NetBSD: fad-gifc.c,v 1.5 2018/09/03 15:26:43 christos Exp $ */ 2 3 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */ 4 /* 5 * Copyright (c) 1994, 1995, 1996, 1997, 1998 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the Computer Systems 19 * Engineering Group at Lawrence Berkeley Laboratory. 20 * 4. Neither the name of the University nor of the Laboratory may be used 21 * to endorse or promote products derived from this software without 22 * specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __RCSID("$NetBSD: fad-gifc.c,v 1.5 2018/09/03 15:26:43 christos Exp $"); 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 #ifdef HAVE_LIMITS_H 66 #include <limits.h> 67 #else 68 #define INT_MAX 2147483647 69 #endif 70 71 #include "pcap-int.h" 72 73 #ifdef HAVE_OS_PROTO_H 74 #include "os-proto.h" 75 #endif 76 77 /* 78 * This is fun. 79 * 80 * In older BSD systems, socket addresses were fixed-length, and 81 * "sizeof (struct sockaddr)" gave the size of the structure. 82 * All addresses fit within a "struct sockaddr". 83 * 84 * In newer BSD systems, the socket address is variable-length, and 85 * there's an "sa_len" field giving the length of the structure; 86 * this allows socket addresses to be longer than 2 bytes of family 87 * and 14 bytes of data. 88 * 89 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553 90 * variant of the old BSD scheme (with "struct sockaddr_storage" rather 91 * than "struct sockaddr"), and some use the new BSD scheme. 92 * 93 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()" 94 * macro that determines the size based on the address family. Other 95 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553 96 * but not in the final version). 97 * 98 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have 99 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the 100 * address in an entry returned by SIOCGIFCONF. 101 */ 102 #ifndef SA_LEN 103 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN 104 #define SA_LEN(addr) ((addr)->sa_len) 105 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 106 #define SA_LEN(addr) (sizeof (struct sockaddr)) 107 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 108 #endif /* SA_LEN */ 109 110 /* 111 * This is also fun. 112 * 113 * There is no ioctl that returns the amount of space required for all 114 * the data that SIOCGIFCONF could return, and if a buffer is supplied 115 * that's not large enough for all the data SIOCGIFCONF could return, 116 * on at least some platforms it just returns the data that'd fit with 117 * no indication that there wasn't enough room for all the data, much 118 * less an indication of how much more room is required. 119 * 120 * The only way to ensure that we got all the data is to pass a buffer 121 * large enough that the amount of space in the buffer *not* filled in 122 * is greater than the largest possible entry. 123 * 124 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption 125 * that no address is more than 255 bytes (on systems where the "sa_len" 126 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the 127 * case, and addresses are unlikely to be bigger than that in any case). 128 */ 129 #define MAX_SA_LEN 255 130 131 /* 132 * Get a list of all interfaces that are up and that we can open. 133 * Returns -1 on error, 0 otherwise. 134 * The list, as returned through "alldevsp", may be null if no interfaces 135 * were up and could be opened. 136 * 137 * This is the implementation used on platforms that have SIOCGIFCONF but 138 * don't have any other mechanism for getting a list of interfaces. 139 * 140 * XXX - or platforms that have other, better mechanisms but for which 141 * we don't yet have code to use that mechanism; I think there's a better 142 * way on Linux, for example, but if that better way is "getifaddrs()", 143 * we already have that. 144 */ 145 int 146 pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf, 147 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 148 { 149 register int fd; 150 register struct ifreq *ifrp, *ifend, *ifnext; 151 size_t n; 152 struct ifconf ifc; 153 char *buf = NULL; 154 unsigned buf_size; 155 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 156 char *p, *q; 157 #endif 158 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; 159 struct sockaddr *netmask, *broadaddr, *dstaddr; 160 size_t netmask_size, broadaddr_size, dstaddr_size; 161 int ret = 0; 162 163 /* 164 * Create a socket from which to fetch the list of interfaces. 165 */ 166 fd = socket(AF_INET, SOCK_DGRAM, 0); 167 if (fd < 0) { 168 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 169 errno, "socket"); 170 return (-1); 171 } 172 173 /* 174 * Start with an 8K buffer, and keep growing the buffer until 175 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN" 176 * bytes left over in the buffer or we fail to get the 177 * interface list for some reason other than EINVAL (which is 178 * presumed here to mean "buffer is too small"). 179 */ 180 buf_size = 8192; 181 for (;;) { 182 /* 183 * Don't let the buffer size get bigger than INT_MAX. 184 */ 185 if (buf_size > INT_MAX) { 186 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 187 "interface information requires more than %u bytes", 188 INT_MAX); 189 (void)close(fd); 190 return (-1); 191 } 192 buf = malloc(buf_size); 193 if (buf == NULL) { 194 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 195 errno, "malloc"); 196 (void)close(fd); 197 return (-1); 198 } 199 200 ifc.ifc_len = buf_size; 201 ifc.ifc_buf = buf; 202 memset(buf, 0, buf_size); 203 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 204 && errno != EINVAL) { 205 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 206 errno, "SIOCGIFCONF"); 207 (void)close(fd); 208 free(buf); 209 return (-1); 210 } 211 if (ifc.ifc_len < (int)buf_size && 212 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 213 break; 214 free(buf); 215 buf_size *= 2; 216 } 217 218 ifrp = (struct ifreq *)buf; 219 ifend = (struct ifreq *)(buf + ifc.ifc_len); 220 221 for (; ifrp < ifend; ifrp = ifnext) { 222 /* 223 * XXX - what if this isn't an IPv4 address? Can 224 * we still get the netmask, etc. with ioctls on 225 * an IPv4 socket? 226 * 227 * The answer is probably platform-dependent, and 228 * if the answer is "no" on more than one platform, 229 * the way you work around it is probably platform- 230 * dependent as well. 231 */ 232 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 233 if (n < sizeof(*ifrp)) 234 ifnext = ifrp + 1; 235 else 236 ifnext = (struct ifreq *)((char *)ifrp + n); 237 238 /* 239 * XXX - The 32-bit compatibility layer for Linux on IA-64 240 * is slightly broken. It correctly converts the structures 241 * to and from kernel land from 64 bit to 32 bit but 242 * doesn't update ifc.ifc_len, leaving it larger than the 243 * amount really used. This means we read off the end 244 * of the buffer and encounter an interface with an 245 * "empty" name. Since this is highly unlikely to ever 246 * occur in a valid case we can just finish looking for 247 * interfaces if we see an empty name. 248 */ 249 if (!(*ifrp->ifr_name)) 250 break; 251 252 /* 253 * Skip entries that begin with "dummy". 254 * XXX - what are these? Is this Linux-specific? 255 * Are there platforms on which we shouldn't do this? 256 */ 257 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 258 continue; 259 260 /* 261 * Can we capture on this device? 262 */ 263 if (!(*check_usable)(ifrp->ifr_name)) { 264 /* 265 * No. 266 */ 267 continue; 268 } 269 270 /* 271 * Get the flags for this interface. 272 */ 273 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 274 sizeof(ifrflags.ifr_name)); 275 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 276 if (errno == ENXIO) 277 continue; 278 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 279 errno, "SIOCGIFFLAGS: %.*s", 280 (int)sizeof(ifrflags.ifr_name), 281 ifrflags.ifr_name); 282 ret = -1; 283 break; 284 } 285 286 /* 287 * Get the netmask for this address on this interface. 288 */ 289 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 290 sizeof(ifrnetmask.ifr_name)); 291 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 292 sizeof(ifrnetmask.ifr_addr)); 293 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 294 if (errno == EADDRNOTAVAIL) { 295 /* 296 * Not available. 297 */ 298 netmask = NULL; 299 netmask_size = 0; 300 } else { 301 pcap_fmt_errmsg_for_errno(errbuf, 302 PCAP_ERRBUF_SIZE, errno, 303 "SIOCGIFNETMASK: %.*s", 304 (int)sizeof(ifrnetmask.ifr_name), 305 ifrnetmask.ifr_name); 306 ret = -1; 307 break; 308 } 309 } else { 310 netmask = &ifrnetmask.ifr_addr; 311 netmask_size = SA_LEN(netmask); 312 } 313 314 /* 315 * Get the broadcast address for this address on this 316 * interface (if any). 317 */ 318 if (ifrflags.ifr_flags & IFF_BROADCAST) { 319 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 320 sizeof(ifrbroadaddr.ifr_name)); 321 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 322 sizeof(ifrbroadaddr.ifr_addr)); 323 if (ioctl(fd, SIOCGIFBRDADDR, 324 (char *)&ifrbroadaddr) < 0) { 325 if (errno == EADDRNOTAVAIL) { 326 /* 327 * Not available. 328 */ 329 broadaddr = NULL; 330 broadaddr_size = 0; 331 } else { 332 pcap_fmt_errmsg_for_errno(errbuf, 333 PCAP_ERRBUF_SIZE, errno, 334 "SIOCGIFBRDADDR: %.*s", 335 (int)sizeof(ifrbroadaddr.ifr_name), 336 ifrbroadaddr.ifr_name); 337 ret = -1; 338 break; 339 } 340 } else { 341 broadaddr = &ifrbroadaddr.ifr_broadaddr; 342 broadaddr_size = SA_LEN(broadaddr); 343 } 344 } else { 345 /* 346 * Not a broadcast interface, so no broadcast 347 * address. 348 */ 349 broadaddr = NULL; 350 broadaddr_size = 0; 351 } 352 353 /* 354 * Get the destination address for this address on this 355 * interface (if any). 356 */ 357 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 358 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 359 sizeof(ifrdstaddr.ifr_name)); 360 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 361 sizeof(ifrdstaddr.ifr_addr)); 362 if (ioctl(fd, SIOCGIFDSTADDR, 363 (char *)&ifrdstaddr) < 0) { 364 if (errno == EADDRNOTAVAIL) { 365 /* 366 * Not available. 367 */ 368 dstaddr = NULL; 369 dstaddr_size = 0; 370 } else { 371 pcap_fmt_errmsg_for_errno(errbuf, 372 PCAP_ERRBUF_SIZE, errno, 373 "SIOCGIFDSTADDR: %.*s", 374 (int)sizeof(ifrdstaddr.ifr_name), 375 ifrdstaddr.ifr_name); 376 ret = -1; 377 break; 378 } 379 } else { 380 dstaddr = &ifrdstaddr.ifr_dstaddr; 381 dstaddr_size = SA_LEN(dstaddr); 382 } 383 } else { 384 /* 385 * Not a point-to-point interface, so no destination 386 * address. 387 */ 388 dstaddr = NULL; 389 dstaddr_size = 0; 390 } 391 392 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 393 /* 394 * If this entry has a colon followed by a number at 395 * the end, it's a logical interface. Those are just 396 * the way you assign multiple IP addresses to a real 397 * interface, so an entry for a logical interface should 398 * be treated like the entry for the real interface; 399 * we do that by stripping off the ":" and the number. 400 */ 401 p = strchr(ifrp->ifr_name, ':'); 402 if (p != NULL) { 403 /* 404 * We have a ":"; is it followed by a number? 405 */ 406 q = p + 1; 407 while (isdigit((unsigned char)*q)) 408 q++; 409 if (*q == '\0') { 410 /* 411 * All digits after the ":" until the end. 412 * Strip off the ":" and everything after 413 * it. 414 */ 415 *p = '\0'; 416 } 417 } 418 #endif 419 420 /* 421 * Add information for this address to the list. 422 */ 423 if (add_addr_to_if(devlistp, ifrp->ifr_name, 424 ifrflags.ifr_flags, get_flags_func, 425 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr), 426 netmask, netmask_size, broadaddr, broadaddr_size, 427 dstaddr, dstaddr_size, errbuf) < 0) { 428 ret = -1; 429 break; 430 } 431 } 432 free(buf); 433 (void)close(fd); 434 435 return (ret); 436 } 437