1 /* $NetBSD: fad-gifc.c,v 1.6 2023/08/17 15:18:12 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 1.6 2023/08/17 15:18:12 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 <errno.h> 58 #include <memory.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 #include <limits.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_STRUCT_SOCKADDR_SA_LEN 98 #define SA_LEN(addr) ((addr)->sa_len) 99 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */ 100 #define SA_LEN(addr) (sizeof (struct sockaddr)) 101 #endif /* HAVE_STRUCT_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_list_t *devlistp, char *errbuf, 141 int (*check_usable)(const char *), get_if_flags_func get_flags_func) 142 { 143 register int fd; 144 register struct ifreq *ifrp, *ifend, *ifnext; 145 size_t 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 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 163 errno, "socket"); 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 /* 177 * Don't let the buffer size get bigger than INT_MAX. 178 */ 179 if (buf_size > INT_MAX) { 180 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 181 "interface information requires more than %u bytes", 182 INT_MAX); 183 (void)close(fd); 184 return (-1); 185 } 186 buf = malloc(buf_size); 187 if (buf == NULL) { 188 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 189 errno, "malloc"); 190 (void)close(fd); 191 return (-1); 192 } 193 194 ifc.ifc_len = buf_size; 195 ifc.ifc_buf = buf; 196 memset(buf, 0, buf_size); 197 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 198 && errno != EINVAL) { 199 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 200 errno, "SIOCGIFCONF"); 201 (void)close(fd); 202 free(buf); 203 return (-1); 204 } 205 if (ifc.ifc_len < (int)buf_size && 206 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN) 207 break; 208 free(buf); 209 buf_size *= 2; 210 } 211 212 ifrp = (struct ifreq *)buf; 213 ifend = (struct ifreq *)(buf + ifc.ifc_len); 214 215 for (; ifrp < ifend; ifrp = ifnext) { 216 /* 217 * XXX - what if this isn't an IPv4 address? Can 218 * we still get the netmask, etc. with ioctls on 219 * an IPv4 socket? 220 * 221 * The answer is probably platform-dependent, and 222 * if the answer is "no" on more than one platform, 223 * the way you work around it is probably platform- 224 * dependent as well. 225 */ 226 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); 227 if (n < sizeof(*ifrp)) 228 ifnext = ifrp + 1; 229 else 230 ifnext = (struct ifreq *)((char *)ifrp + n); 231 232 /* 233 * XXX - The 32-bit compatibility layer for Linux on IA-64 234 * is slightly broken. It correctly converts the structures 235 * to and from kernel land from 64 bit to 32 bit but 236 * doesn't update ifc.ifc_len, leaving it larger than the 237 * amount really used. This means we read off the end 238 * of the buffer and encounter an interface with an 239 * "empty" name. Since this is highly unlikely to ever 240 * occur in a valid case we can just finish looking for 241 * interfaces if we see an empty name. 242 */ 243 if (!(*ifrp->ifr_name)) 244 break; 245 246 /* 247 * Skip entries that begin with "dummy". 248 * XXX - what are these? Is this Linux-specific? 249 * Are there platforms on which we shouldn't do this? 250 */ 251 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0) 252 continue; 253 254 /* 255 * Can we capture on this device? 256 */ 257 if (!(*check_usable)(ifrp->ifr_name)) { 258 /* 259 * No. 260 */ 261 continue; 262 } 263 264 /* 265 * Get the flags for this interface. 266 */ 267 strncpy(ifrflags.ifr_name, ifrp->ifr_name, 268 sizeof(ifrflags.ifr_name)); 269 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 270 if (errno == ENXIO) 271 continue; 272 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 273 errno, "SIOCGIFFLAGS: %.*s", 274 (int)sizeof(ifrflags.ifr_name), 275 ifrflags.ifr_name); 276 ret = -1; 277 break; 278 } 279 280 /* 281 * Get the netmask for this address on this interface. 282 */ 283 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, 284 sizeof(ifrnetmask.ifr_name)); 285 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, 286 sizeof(ifrnetmask.ifr_addr)); 287 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { 288 if (errno == EADDRNOTAVAIL) { 289 /* 290 * Not available. 291 */ 292 netmask = NULL; 293 netmask_size = 0; 294 } else { 295 pcap_fmt_errmsg_for_errno(errbuf, 296 PCAP_ERRBUF_SIZE, errno, 297 "SIOCGIFNETMASK: %.*s", 298 (int)sizeof(ifrnetmask.ifr_name), 299 ifrnetmask.ifr_name); 300 ret = -1; 301 break; 302 } 303 } else { 304 netmask = &ifrnetmask.ifr_addr; 305 netmask_size = SA_LEN(netmask); 306 } 307 308 /* 309 * Get the broadcast address for this address on this 310 * interface (if any). 311 */ 312 if (ifrflags.ifr_flags & IFF_BROADCAST) { 313 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, 314 sizeof(ifrbroadaddr.ifr_name)); 315 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, 316 sizeof(ifrbroadaddr.ifr_addr)); 317 if (ioctl(fd, SIOCGIFBRDADDR, 318 (char *)&ifrbroadaddr) < 0) { 319 if (errno == EADDRNOTAVAIL) { 320 /* 321 * Not available. 322 */ 323 broadaddr = NULL; 324 broadaddr_size = 0; 325 } else { 326 pcap_fmt_errmsg_for_errno(errbuf, 327 PCAP_ERRBUF_SIZE, errno, 328 "SIOCGIFBRDADDR: %.*s", 329 (int)sizeof(ifrbroadaddr.ifr_name), 330 ifrbroadaddr.ifr_name); 331 ret = -1; 332 break; 333 } 334 } else { 335 broadaddr = &ifrbroadaddr.ifr_broadaddr; 336 broadaddr_size = SA_LEN(broadaddr); 337 } 338 } else { 339 /* 340 * Not a broadcast interface, so no broadcast 341 * address. 342 */ 343 broadaddr = NULL; 344 broadaddr_size = 0; 345 } 346 347 /* 348 * Get the destination address for this address on this 349 * interface (if any). 350 */ 351 if (ifrflags.ifr_flags & IFF_POINTOPOINT) { 352 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, 353 sizeof(ifrdstaddr.ifr_name)); 354 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, 355 sizeof(ifrdstaddr.ifr_addr)); 356 if (ioctl(fd, SIOCGIFDSTADDR, 357 (char *)&ifrdstaddr) < 0) { 358 if (errno == EADDRNOTAVAIL) { 359 /* 360 * Not available. 361 */ 362 dstaddr = NULL; 363 dstaddr_size = 0; 364 } else { 365 pcap_fmt_errmsg_for_errno(errbuf, 366 PCAP_ERRBUF_SIZE, errno, 367 "SIOCGIFDSTADDR: %.*s", 368 (int)sizeof(ifrdstaddr.ifr_name), 369 ifrdstaddr.ifr_name); 370 ret = -1; 371 break; 372 } 373 } else { 374 dstaddr = &ifrdstaddr.ifr_dstaddr; 375 dstaddr_size = SA_LEN(dstaddr); 376 } 377 } else { 378 /* 379 * Not a point-to-point interface, so no destination 380 * address. 381 */ 382 dstaddr = NULL; 383 dstaddr_size = 0; 384 } 385 386 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER) 387 /* 388 * If this entry has a colon followed by a number at 389 * the end, it's a logical interface. Those are just 390 * the way you assign multiple IP addresses to a real 391 * interface, so an entry for a logical interface should 392 * be treated like the entry for the real interface; 393 * we do that by stripping off the ":" and the number. 394 */ 395 p = strchr(ifrp->ifr_name, ':'); 396 if (p != NULL) { 397 /* 398 * We have a ":"; is it followed by a number? 399 */ 400 q = p + 1; 401 while (PCAP_ISDIGIT(*q)) 402 q++; 403 if (*q == '\0') { 404 /* 405 * All digits after the ":" until the end. 406 * Strip off the ":" and everything after 407 * it. 408 */ 409 *p = '\0'; 410 } 411 } 412 #endif 413 414 /* 415 * Add information for this address to the list. 416 */ 417 if (add_addr_to_if(devlistp, ifrp->ifr_name, 418 ifrflags.ifr_flags, get_flags_func, 419 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr), 420 netmask, netmask_size, broadaddr, broadaddr_size, 421 dstaddr, dstaddr_size, errbuf) < 0) { 422 ret = -1; 423 break; 424 } 425 } 426 free(buf); 427 (void)close(fd); 428 429 return (ret); 430 } 431