arp.c revision 1.58.4.3
1 /* $NetBSD: arp.c,v 1.58.4.3 2018/09/06 06:56:50 pgoyette Exp $ */ 2 3 /* 4 * Copyright (c) 1984, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Sun Microsystems, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without 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 <sys/cdefs.h> 36 #ifndef lint 37 __COPYRIGHT("@(#) Copyright (c) 1984, 1993\ 38 The Regents of the University of California. All rights reserved."); 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 44 #else 45 __RCSID("$NetBSD: arp.c,v 1.58.4.3 2018/09/06 06:56:50 pgoyette Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 /* 50 * arp - display, set, and delete arp table entries 51 */ 52 53 #include <sys/param.h> 54 #include <sys/file.h> 55 #include <sys/socket.h> 56 #include <sys/sysctl.h> 57 #include <sys/ioctl.h> 58 59 #include <net/if.h> 60 #include <net/if_dl.h> 61 #include <net/if_ether.h> 62 #include <net/if_types.h> 63 #include <net/route.h> 64 #include <netinet/in.h> 65 #include <netinet/if_inarp.h> 66 #include <arpa/inet.h> 67 68 #include <err.h> 69 #include <errno.h> 70 #include <netdb.h> 71 #include <nlist.h> 72 #include <paths.h> 73 #include <stdio.h> 74 #include <stdlib.h> 75 #include <string.h> 76 #include <unistd.h> 77 #include <ifaddrs.h> 78 79 #include "prog_ops.h" 80 81 static int is_llinfo(const struct sockaddr_dl *, int); 82 static int delete_one(struct rt_msghdr *); 83 static void dump(uint32_t); 84 static void delete(const char *, const char *); 85 static void sdl_print(const struct sockaddr_dl *); 86 static int getifname(u_int16_t, char *, size_t); 87 static int atosdl(const char *, struct sockaddr_dl *); 88 static int file(const char *); 89 static void get(const char *); 90 static int getinetaddr(const char *, struct in_addr *); 91 static int getsocket(void); 92 static int getetheraddr(struct in_addr, struct sockaddr_dl *); 93 static struct rt_msghdr * rtmsg(const int, const int, struct rt_msghdr *, 94 const struct sockaddr_inarp *, const struct sockaddr_dl *); 95 static int set(int, char **); 96 static void usage(void) __dead; 97 98 static int aflag, nflag, vflag; 99 static struct sockaddr_in so_mask = { 100 .sin_len = 8, 101 .sin_addr = { 102 .s_addr = 0xffffffff 103 } 104 }; 105 static struct sockaddr_inarp blank_sin = { 106 .sin_len = sizeof(blank_sin), 107 .sin_family = AF_INET 108 }; 109 static struct sockaddr_dl blank_sdl = { 110 .sdl_len = sizeof(blank_sdl), 111 .sdl_family = AF_LINK 112 }; 113 114 static int expire_time, flags, export_only, doing_proxy, found_entry; 115 116 int 117 main(int argc, char **argv) 118 { 119 int ch; 120 int op = 0; 121 122 setprogname(argv[0]); 123 124 while ((ch = getopt(argc, argv, "andsfv")) != -1) 125 switch((char)ch) { 126 case 'a': 127 aflag = 1; 128 break; 129 case 'd': 130 case 's': 131 case 'f': 132 if (op) 133 usage(); 134 op = ch; 135 break; 136 case 'n': 137 nflag = 1; 138 break; 139 case 'v': 140 vflag = 1; 141 break; 142 default: 143 usage(); 144 } 145 argc -= optind; 146 argv += optind; 147 148 if (!op && aflag) 149 op = 'a'; 150 151 if (prog_init && prog_init() == -1) 152 err(1, "init failed"); 153 154 switch((char)op) { 155 case 'a': 156 dump(0); 157 break; 158 case 'd': 159 if (aflag && argc == 0) 160 delete(NULL, NULL); 161 else { 162 if (aflag || argc < 1 || argc > 2) 163 usage(); 164 delete(argv[0], argv[1]); 165 } 166 break; 167 case 's': 168 if (argc < 2 || argc > 7) 169 usage(); 170 return (set(argc, argv) ? 1 : 0); 171 case 'f': 172 if (argc != 1) 173 usage(); 174 return (file(argv[0])); 175 default: 176 if (argc != 1) 177 usage(); 178 get(argv[0]); 179 break; 180 } 181 return (0); 182 } 183 184 /* 185 * Process a file to set standard arp entries 186 */ 187 static int 188 file(const char *name) 189 { 190 char *line, *argv[5]; 191 int i, retval; 192 FILE *fp; 193 194 if (!strcmp(name, "-")) { 195 fp = stdin; 196 } else { 197 fp = fopen(name, "r"); 198 if (fp == NULL) { 199 err(1, "Cannot open %s", name); 200 } 201 } 202 retval = 0; 203 for (; (line = fparseln(fp, NULL, NULL, NULL, 0)) != NULL; free(line)) { 204 char **ap, *inputstring; 205 206 inputstring = line; 207 for (ap = argv; ap < &argv[sizeof(argv) / sizeof(argv[0])] && 208 (*ap = stresep(&inputstring, " \t", '\\')) != NULL;) { 209 if (**ap != '\0') 210 ap++; 211 } 212 i = ap - argv; 213 if (i < 2) { 214 warnx("bad line: %s", line); 215 retval = 1; 216 continue; 217 } 218 if (set(i, argv)) 219 retval = 1; 220 } 221 if (fp != stdin) 222 (void)fclose(fp); 223 return retval; 224 } 225 226 static int 227 getsocket(void) 228 { 229 int s; 230 s = prog_socket(PF_ROUTE, SOCK_RAW, 0); 231 if (s < 0) 232 err(1, "socket"); 233 return s; 234 } 235 236 static int 237 getlink(const char *name, struct sockaddr_dl *sdl) 238 { 239 struct ifaddrs *ifap, *ifa; 240 241 if (getifaddrs(&ifap) != 0) { 242 warn("getifaddrs"); 243 return 0; 244 } 245 246 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 247 if (ifa->ifa_addr->sa_family != AF_LINK) 248 continue; 249 if (strcmp(ifa->ifa_name, name) != 0) 250 continue; 251 memcpy(sdl, ifa->ifa_addr, sizeof(*sdl)); 252 freeifaddrs(ifap); 253 return 1; 254 } 255 freeifaddrs(ifap); 256 return 0; 257 } 258 259 /* 260 * Set an individual arp entry 261 */ 262 static int 263 set(int argc, char **argv) 264 { 265 struct sockaddr_inarp *sina; 266 struct sockaddr_dl *sdl = NULL; 267 struct rt_msghdr *rtm; 268 char *host = argv[0], *eaddr; 269 struct sockaddr_inarp sin_m = blank_sin; /* struct copy */ 270 struct sockaddr_dl sdl_m = blank_sdl; /* struct copy */ 271 int s; 272 273 eaddr = argv[1]; 274 275 s = getsocket(); 276 argc -= 2; 277 argv += 2; 278 279 if (getinetaddr(host, &sin_m.sin_addr) == -1) 280 return (1); 281 if (strcmp(eaddr, "auto") != 0 && atosdl(eaddr, &sdl_m)) 282 warnx("invalid link-level address '%s'", eaddr); 283 doing_proxy = flags = export_only = expire_time = 0; 284 for (; argc-- > 0; argv++) { 285 if (strncmp(argv[0], "temp", 4) == 0) { 286 struct timeval timev; 287 (void)gettimeofday(&timev, 0); 288 expire_time = timev.tv_sec + 20 * 60; 289 } 290 else if (strncmp(argv[0], "pub", 3) == 0) { 291 flags |= RTF_ANNOUNCE; 292 doing_proxy = 1; 293 if (argc && strncmp(argv[1], "pro", 3) == 0) { 294 export_only = 1; 295 argc--; argv++; 296 } 297 } else if (strncmp(argv[0], "trail", 5) == 0) { 298 warnx("%s: Sending trailers is no longer supported", 299 host); 300 } else if (strcmp(argv[0], "ifscope") == 0) { 301 if (argc == 0) { 302 warnx("missing interface for ifscope"); 303 continue; 304 } 305 argc--; 306 argv++; 307 if (!getlink(argv[0], &sdl_m)) 308 warnx("cannot get link address for %s", argv[0]); 309 } 310 311 } 312 if (doing_proxy && strcmp(eaddr, "auto") == 0) { 313 if (getetheraddr(sin_m.sin_addr, &sdl_m) == -1) 314 return 1; 315 } 316 tryagain: 317 rtm = rtmsg(s, RTM_GET, NULL, &sin_m, &sdl_m); 318 if (rtm == NULL) { 319 warn("%s", host); 320 return (1); 321 } 322 sina = (struct sockaddr_inarp *)(void *)(rtm + 1); 323 sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) + 324 (char *)(void *)sina); 325 if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 326 if (is_llinfo(sdl, rtm->rtm_flags)) 327 goto overwrite; 328 if (doing_proxy == 0) { 329 warnx("set: can only proxy for %s", host); 330 return (1); 331 } 332 if (sin_m.sin_other & SIN_PROXY) { 333 warnx("set: proxy entry exists for non 802 device"); 334 return (1); 335 } 336 sin_m.sin_other = SIN_PROXY; 337 export_only = 1; 338 goto tryagain; 339 } 340 overwrite: 341 if (sdl->sdl_family != AF_LINK) { 342 warnx("cannot intuit interface index and type for %s", 343 host); 344 return (1); 345 } 346 sdl_m.sdl_type = sdl->sdl_type; 347 sdl_m.sdl_index = sdl->sdl_index; 348 sin_m.sin_other = 0; 349 if (doing_proxy && export_only) 350 sin_m.sin_other = SIN_PROXY; 351 rtm = rtmsg(s, RTM_ADD, NULL, &sin_m, &sdl_m); 352 if (vflag) 353 (void)printf("%s (%s) added\n", host, eaddr); 354 return (rtm == NULL) ? 1 : 0; 355 } 356 357 /* 358 * Display an individual arp entry 359 */ 360 static void 361 get(const char *host) 362 { 363 struct sockaddr_inarp sin = blank_sin; /* struct copy */ 364 365 if (getinetaddr(host, &sin.sin_addr) == -1) 366 exit(1); 367 dump(sin.sin_addr.s_addr); 368 if (found_entry == 0) 369 errx(1, "%s (%s) -- no entry", host, inet_ntoa(sin.sin_addr)); 370 } 371 372 373 static int 374 is_llinfo(const struct sockaddr_dl *sdl, int rtflags) 375 { 376 if (sdl->sdl_family != AF_LINK || 377 (rtflags & (RTF_LLDATA|RTF_GATEWAY)) != RTF_LLDATA) 378 return 0; 379 380 switch (sdl->sdl_type) { 381 case IFT_ETHER: 382 case IFT_FDDI: 383 case IFT_ISO88023: 384 case IFT_ISO88024: 385 case IFT_ISO88025: 386 case IFT_ARCNET: 387 return 1; 388 default: 389 return 0; 390 } 391 } 392 393 /* 394 * Delete an arp entry 395 */ 396 int 397 delete_one(struct rt_msghdr *rtm) 398 { 399 struct sockaddr_inarp *sina; 400 struct sockaddr_dl *sdl; 401 int s; 402 403 s = getsocket(); 404 sina = (struct sockaddr_inarp *)(void *)(rtm + 1); 405 sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) + 406 (char *)(void *)sina); 407 if (sdl->sdl_family != AF_LINK) 408 return (1); 409 rtm = rtmsg(s, RTM_DELETE, rtm, sina, sdl); 410 if (rtm == NULL) 411 return (1); 412 return (0); 413 } 414 415 /* 416 * Dump the entire arp table 417 */ 418 void 419 dump(uint32_t addr) 420 { 421 int mib[6]; 422 size_t needed; 423 char ifname[IFNAMSIZ]; 424 char *lim, *buf, *next; 425 const char *host; 426 struct rt_msghdr *rtm; 427 struct sockaddr_inarp *sina; 428 struct sockaddr_dl *sdl; 429 struct hostent *hp; 430 431 mib[0] = CTL_NET; 432 mib[1] = PF_ROUTE; 433 mib[2] = 0; 434 mib[3] = AF_INET; 435 mib[4] = NET_RT_FLAGS; 436 mib[5] = 0; 437 if (prog_sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 438 err(1, "route-sysctl-estimate"); 439 if (needed == 0) 440 return; 441 if ((buf = malloc(needed)) == NULL) 442 err(1, "malloc"); 443 if (prog_sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 444 err(1, "actual retrieval of routing table"); 445 lim = buf + needed; 446 for (next = buf; next < lim; next += rtm->rtm_msglen) { 447 rtm = (struct rt_msghdr *)(void *)next; 448 sina = (struct sockaddr_inarp *)(void *)(rtm + 1); 449 sdl = (struct sockaddr_dl *)(void *) 450 (RT_ROUNDUP(sina->sin_len) + (char *)(void *)sina); 451 if (addr) { 452 if (addr != sina->sin_addr.s_addr) 453 continue; 454 found_entry = 1; 455 } 456 if (nflag == 0) 457 hp = gethostbyaddr((const char *)(void *) 458 &(sina->sin_addr), 459 sizeof sina->sin_addr, AF_INET); 460 else 461 hp = NULL; 462 463 host = hp ? hp->h_name : "?"; 464 465 (void)printf("%s (%s) at ", host, inet_ntoa(sina->sin_addr)); 466 if (sdl->sdl_alen) 467 sdl_print(sdl); 468 else 469 (void)printf("(incomplete)"); 470 471 if (sdl->sdl_index) { 472 if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0) 473 (void)printf(" on %s", ifname); 474 } 475 476 if (rtm->rtm_rmx.rmx_expire == 0) 477 (void)printf(" permanent"); 478 if (sina->sin_other & SIN_PROXY) 479 (void)printf(" published (proxy only)"); 480 if (rtm->rtm_addrs & RTA_NETMASK) { 481 sina = (struct sockaddr_inarp *)(void *) 482 (RT_ROUNDUP(sdl->sdl_len) + (char *)(void *)sdl); 483 if (sina->sin_addr.s_addr == 0xffffffff) 484 (void)printf(" published"); 485 if (sina->sin_len != 8) 486 (void)printf("(weird)"); 487 } 488 (void)printf("\n"); 489 } 490 free(buf); 491 } 492 493 /* 494 * Delete the entire arp table 495 */ 496 void 497 delete(const char *host, const char *info) 498 { 499 int mib[6]; 500 char addr[sizeof("000.000.000.000\0")]; 501 size_t needed; 502 char *lim, *buf, *next; 503 struct rt_msghdr *rtm; 504 struct sockaddr_inarp *sina; 505 struct sockaddr_inarp sin_m = blank_sin; /* struct copy */ 506 bool found = false; 507 508 if (host != NULL) { 509 int ret = getinetaddr(host, &sin_m.sin_addr); 510 if (ret == -1) 511 return; 512 } 513 if (info && strncmp(info, "pro", 3) == 0) 514 sin_m.sin_other = SIN_PROXY; 515 516 retry: 517 mib[0] = CTL_NET; 518 mib[1] = PF_ROUTE; 519 mib[2] = 0; 520 mib[3] = AF_INET; 521 mib[4] = NET_RT_FLAGS; 522 mib[5] = RTF_LLDATA; 523 if (prog_sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 524 err(1, "route-sysctl-estimate"); 525 if (needed == 0) 526 return; 527 if ((buf = malloc(needed)) == NULL) 528 err(1, "malloc"); 529 if (prog_sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { 530 free(buf); 531 if (errno == ENOBUFS) 532 goto retry; 533 err(1, "actual retrieval of routing table"); 534 } 535 lim = buf + needed; 536 537 for (next = buf; next < lim; next += rtm->rtm_msglen) { 538 int ret; 539 rtm = (struct rt_msghdr *)(void *)next; 540 sina = (struct sockaddr_inarp *)(void *)(rtm + 1); 541 if (host != NULL && 542 sina->sin_addr.s_addr != sin_m.sin_addr.s_addr) 543 continue; 544 found = true; 545 ret = delete_one(rtm); 546 if (vflag && ret == 0) { 547 snprintf(addr, sizeof(addr), "%s", 548 inet_ntoa(sina->sin_addr)); 549 (void)printf("%s (%s) deleted\n", 550 host != NULL ? host : addr, addr); 551 } 552 } 553 if (host != NULL && !found) 554 warnx("delete: can't locate %s", host); 555 free(buf); 556 } 557 558 void 559 sdl_print(const struct sockaddr_dl *sdl) 560 { 561 char hbuf[NI_MAXHOST]; 562 563 if (getnameinfo((const struct sockaddr *)(const void *)sdl, 564 (socklen_t)sdl->sdl_len, 565 hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) 566 (void)printf("<invalid>"); 567 else 568 (void)printf("%s", hbuf); 569 } 570 571 static int 572 atosdl(const char *ss, struct sockaddr_dl *sdl) 573 { 574 int i; 575 unsigned long b; 576 char *endp; 577 char *p; 578 char *t, *r; 579 580 p = LLADDR(sdl); 581 endp = ((char *)(void *)sdl) + sdl->sdl_len; 582 i = 0; 583 584 b = strtoul(ss, &t, 16); 585 if (b > 255 || t == ss) 586 return 1; 587 588 *p++ = (char)b; 589 ++i; 590 while ((p < endp) && (*t++ == ':')) { 591 b = strtoul(t, &r, 16); 592 if (b > 255 || r == t) 593 break; 594 *p++ = (char)b; 595 ++i; 596 t = r; 597 } 598 sdl->sdl_alen = i; 599 600 return 0; 601 } 602 603 static void 604 usage(void) 605 { 606 const char *progname; 607 608 progname = getprogname(); 609 (void)fprintf(stderr, "Usage: %s [-n] hostname\n", progname); 610 (void)fprintf(stderr, " %s [-nv] -a\n", progname); 611 (void)fprintf(stderr, " %s [-v] -d [-a|hostname [proxy]]\n", 612 progname); 613 (void)fprintf(stderr, " %s -s hostname ether_addr [temp] [pub [proxy]]\n", 614 progname); 615 (void)fprintf(stderr, " %s -f filename\n", progname); 616 exit(1); 617 } 618 619 static struct rt_msghdr * 620 rtmsg(const int s, const int cmd, struct rt_msghdr *_rtm, 621 const struct sockaddr_inarp *sin, const struct sockaddr_dl *sdl) 622 { 623 static int seq; 624 struct rt_msghdr *rtm = _rtm; 625 char *cp; 626 int l; 627 static struct { 628 struct rt_msghdr m_rtm; 629 char m_space[512]; 630 } m_rtmsg; 631 pid_t pid; 632 633 errno = 0; 634 if (rtm != NULL) { 635 memcpy(&m_rtmsg, rtm, rtm->rtm_msglen); 636 rtm = &m_rtmsg.m_rtm; 637 goto doit; 638 } 639 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 640 rtm = &m_rtmsg.m_rtm; 641 cp = m_rtmsg.m_space; 642 643 rtm->rtm_flags = flags; 644 rtm->rtm_version = RTM_VERSION; 645 646 switch (cmd) { 647 default: 648 errx(1, "internal wrong cmd"); 649 /*NOTREACHED*/ 650 case RTM_ADD: 651 rtm->rtm_addrs |= RTA_GATEWAY; 652 rtm->rtm_rmx.rmx_expire = expire_time; 653 rtm->rtm_inits = RTV_EXPIRE; 654 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 655 if (doing_proxy) { 656 if (!export_only) { 657 rtm->rtm_addrs |= RTA_NETMASK; 658 rtm->rtm_flags &= ~RTF_HOST; 659 } 660 } 661 rtm->rtm_addrs |= RTA_DST; 662 break; 663 case RTM_GET: 664 rtm->rtm_flags |= RTF_LLDATA; 665 rtm->rtm_addrs |= RTA_DST | RTA_GATEWAY; 666 } 667 668 #define NEXTADDR(w, s) \ 669 if (rtm->rtm_addrs & (w)) { \ 670 (void)memcpy(cp, &s, \ 671 (size_t)((const struct sockaddr *)&s)->sa_len); \ 672 RT_ADVANCE(cp, ((const struct sockaddr *)&s)); \ 673 } 674 675 NEXTADDR(RTA_DST, *sin); 676 NEXTADDR(RTA_GATEWAY, *sdl); 677 NEXTADDR(RTA_NETMASK, so_mask); 678 679 rtm->rtm_msglen = cp - (char *)(void *)&m_rtmsg; 680 doit: 681 l = rtm->rtm_msglen; 682 rtm->rtm_seq = ++seq; 683 rtm->rtm_type = cmd; 684 if (prog_write(s, &m_rtmsg, (size_t)l) < 0) { 685 if (errno != ESRCH || cmd != RTM_DELETE) { 686 warn("writing to routing socket"); 687 return NULL; 688 } 689 } 690 691 pid = prog_getpid(); 692 do { 693 l = prog_read(s, &m_rtmsg, sizeof(m_rtmsg)); 694 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 695 if (l < 0) 696 warn("read from routing socket"); 697 return rtm; 698 } 699 700 static int 701 getinetaddr(const char *host, struct in_addr *inap) 702 { 703 struct hostent *hp; 704 705 if (inet_aton(host, inap) == 1) 706 return (0); 707 if ((hp = gethostbyname(host)) == NULL) { 708 warnx("%s: %s", host, hstrerror(h_errno)); 709 return (-1); 710 } 711 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 712 return (0); 713 } 714 715 static int 716 getifname(u_int16_t ifindex, char *ifname, size_t l) 717 { 718 int i; 719 struct ifaddrs *addr; 720 const struct sockaddr_dl *sdl; 721 static struct ifaddrs* ifaddrs = NULL; 722 723 if (ifaddrs == NULL) { 724 i = getifaddrs(&ifaddrs); 725 if (i != 0) 726 err(1, "getifaddrs"); 727 } 728 729 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 730 if (addr->ifa_addr == NULL || 731 addr->ifa_addr->sa_family != AF_LINK) 732 continue; 733 734 sdl = (const struct sockaddr_dl *)(void *)addr->ifa_addr; 735 if (sdl && sdl->sdl_index == ifindex) { 736 (void) strlcpy(ifname, addr->ifa_name, l); 737 return 0; 738 } 739 } 740 741 return -1; 742 } 743 744 static int 745 getetheraddr(struct in_addr ipaddr, struct sockaddr_dl *sdl) 746 { 747 struct ifaddrs *ifaddrs, *addr; 748 in_addr_t ina, mask; 749 char ifname[IFNAMSIZ]; 750 751 if (getifaddrs(&ifaddrs) != 0) { 752 warn("getifaddrs"); 753 return -1; 754 } 755 756 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 757 if (addr->ifa_addr == NULL || 758 addr->ifa_addr->sa_family != AF_INET) 759 continue; 760 if ((addr->ifa_flags & (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 761 IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) 762 continue; 763 764 mask = ((struct sockaddr_in *)(void *)addr->ifa_netmask)->sin_addr.s_addr; 765 ina = ((struct sockaddr_in *)(void *)addr->ifa_addr)->sin_addr.s_addr; 766 if ((ipaddr.s_addr & mask) != (ina & mask)) 767 continue; 768 strlcpy(ifname, addr->ifa_name, sizeof(ifname)); 769 break; 770 } 771 if (addr == NULL) { 772 warnx("No interface matched %s", inet_ntoa(ipaddr)); 773 freeifaddrs(ifaddrs); 774 return -1; 775 } 776 777 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 778 if (addr->ifa_addr == NULL || 779 addr->ifa_addr->sa_family != AF_LINK) 780 continue; 781 if (strcmp(ifname, addr->ifa_name) != 0) 782 continue; 783 memcpy(sdl, addr->ifa_addr, sizeof(*sdl)); 784 freeifaddrs(ifaddrs); 785 return 0; 786 } 787 warnx("No link address for interface %s", ifname); 788 freeifaddrs(ifaddrs); 789 return -1; 790 } 791
Indexes created Tue Sep 30 17:09:57 GMT 2025