1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 #if 0 36 #ifndef lint 37 static char const copyright[] = 38 "@(#) Copyright (c) 1984, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"; 40 #endif /* not lint */ 41 42 #ifndef lint 43 static char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94"; 44 #endif /* not lint */ 45 #endif 46 #include <sys/cdefs.h> 47 /* 48 * arp - display, set, and delete arp table entries 49 */ 50 51 #include <sys/param.h> 52 #include <sys/file.h> 53 #include <sys/socket.h> 54 #include <sys/sockio.h> 55 #include <sys/sysctl.h> 56 #include <sys/ioctl.h> 57 #include <sys/time.h> 58 59 #include <net/if.h> 60 #include <net/if_dl.h> 61 #include <net/if_types.h> 62 #include <net/route.h> 63 64 #include <netinet/in.h> 65 #include <netinet/if_ether.h> 66 67 #include <arpa/inet.h> 68 69 #include <ctype.h> 70 #include <err.h> 71 #include <errno.h> 72 #include <netdb.h> 73 #include <nlist.h> 74 #include <paths.h> 75 #include <stdbool.h> 76 #include <stdio.h> 77 #include <stdlib.h> 78 #include <string.h> 79 #include <strings.h> 80 #include <unistd.h> 81 #include <ifaddrs.h> 82 #include <libxo/xo.h> 83 #include "arp.h" 84 85 typedef void (action_fn)(struct sockaddr_dl *sdl, struct sockaddr_in *s_in, 86 struct rt_msghdr *rtm); 87 static void nuke_entries(uint32_t ifindex, struct in_addr addr); 88 static int print_entries(uint32_t ifindex, struct in_addr addr); 89 90 static int delete(char *host); 91 static void usage(void) __dead2; 92 static int set(int argc, char **argv); 93 static int get(char *host); 94 static int file(char *name); 95 static struct rt_msghdr *rtmsg(int cmd, 96 struct sockaddr_in *dst, struct sockaddr_dl *sdl); 97 static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 98 static int set_rtsock(struct sockaddr_in *dst, struct sockaddr_dl *sdl_m, 99 char *host); 100 101 struct if_nameindex *ifnameindex; 102 103 struct arp_opts opts = {}; 104 105 /* which function we're supposed to do */ 106 #define F_GET 1 107 #define F_SET 2 108 #define F_FILESET 3 109 #define F_REPLACE 4 110 #define F_DELETE 5 111 112 #define SETFUNC(f) { if (func) usage(); func = (f); } 113 114 #define ARP_XO_VERSION "1" 115 116 int 117 main(int argc, char *argv[]) 118 { 119 int ch, func = 0; 120 int rtn = 0; 121 122 argc = xo_parse_args(argc, argv); 123 if (argc < 0) 124 exit(1); 125 126 while ((ch = getopt(argc, argv, "andfsSi:")) != -1) 127 switch(ch) { 128 case 'a': 129 opts.aflag = true; 130 break; 131 case 'd': 132 SETFUNC(F_DELETE); 133 break; 134 case 'n': 135 opts.nflag = true; 136 break; 137 case 'S': 138 SETFUNC(F_REPLACE); 139 break; 140 case 's': 141 SETFUNC(F_SET); 142 break; 143 case 'f' : 144 SETFUNC(F_FILESET); 145 break; 146 case 'i': 147 opts.rifname = optarg; 148 break; 149 case '?': 150 default: 151 usage(); 152 } 153 argc -= optind; 154 argv += optind; 155 156 if (!func) 157 func = F_GET; 158 if (opts.rifname) { 159 if (func != F_GET && !(func == F_DELETE && opts.aflag)) 160 xo_errx(1, "-i not applicable to this operation"); 161 if ((opts.rifindex = if_nametoindex(opts.rifname)) == 0) { 162 if (errno == ENXIO) 163 xo_errx(1, "interface %s does not exist", 164 opts.rifname); 165 else 166 xo_err(1, "if_nametoindex(%s)", opts.rifname); 167 } 168 } 169 switch (func) { 170 case F_GET: 171 if (opts.aflag) { 172 if (argc != 0) 173 usage(); 174 175 xo_set_version(ARP_XO_VERSION); 176 xo_open_container("arp"); 177 xo_open_list("arp-cache"); 178 179 struct in_addr all_addrs = {}; 180 print_entries(opts.rifindex, all_addrs); 181 182 xo_close_list("arp-cache"); 183 xo_close_container("arp"); 184 xo_finish(); 185 } else { 186 if (argc != 1) 187 usage(); 188 rtn = get(argv[0]); 189 } 190 break; 191 case F_SET: 192 case F_REPLACE: 193 if (argc < 2 || argc > 6) 194 usage(); 195 if (func == F_REPLACE) 196 (void)delete(argv[0]); 197 rtn = set(argc, argv) ? 1 : 0; 198 break; 199 case F_DELETE: 200 if (opts.aflag) { 201 if (argc != 0) 202 usage(); 203 struct in_addr all_addrs = {}; 204 nuke_entries(0, all_addrs); 205 } else { 206 if (argc != 1) 207 usage(); 208 rtn = delete(argv[0]); 209 } 210 break; 211 case F_FILESET: 212 if (argc != 1) 213 usage(); 214 rtn = file(argv[0]); 215 break; 216 } 217 218 if (ifnameindex != NULL) 219 if_freenameindex(ifnameindex); 220 221 return (rtn); 222 } 223 224 /* 225 * Process a file to set standard arp entries 226 */ 227 static int 228 file(char *name) 229 { 230 FILE *fp; 231 int i, retval; 232 char line[100], arg[5][50], *args[5], *p; 233 234 if ((fp = fopen(name, "r")) == NULL) 235 xo_err(1, "cannot open %s", name); 236 args[0] = &arg[0][0]; 237 args[1] = &arg[1][0]; 238 args[2] = &arg[2][0]; 239 args[3] = &arg[3][0]; 240 args[4] = &arg[4][0]; 241 retval = 0; 242 while(fgets(line, sizeof(line), fp) != NULL) { 243 if ((p = strchr(line, '#')) != NULL) 244 *p = '\0'; 245 for (p = line; isblank(*p); p++); 246 if (*p == '\n' || *p == '\0') 247 continue; 248 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1], 249 arg[2], arg[3], arg[4]); 250 if (i < 2) { 251 xo_warnx("bad line: %s", line); 252 retval = 1; 253 continue; 254 } 255 if (set(i, args)) 256 retval = 1; 257 } 258 fclose(fp); 259 return (retval); 260 } 261 262 /* 263 * Given a hostname, fills up a (static) struct sockaddr_in with 264 * the address of the host and returns a pointer to the 265 * structure. 266 */ 267 struct sockaddr_in * 268 getaddr(char *host) 269 { 270 struct hostent *hp; 271 static struct sockaddr_in reply; 272 273 bzero(&reply, sizeof(reply)); 274 reply.sin_len = sizeof(reply); 275 reply.sin_family = AF_INET; 276 reply.sin_addr.s_addr = inet_addr(host); 277 if (reply.sin_addr.s_addr == INADDR_NONE) { 278 if (!(hp = gethostbyname(host))) { 279 xo_warnx("%s: %s", host, hstrerror(h_errno)); 280 return (NULL); 281 } 282 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr, 283 sizeof reply.sin_addr); 284 } 285 return (&reply); 286 } 287 288 int valid_type(int type); 289 /* 290 * Returns true if the type is a valid one for ARP. 291 */ 292 int 293 valid_type(int type) 294 { 295 296 switch (type) { 297 case IFT_ETHER: 298 case IFT_FDDI: 299 case IFT_IEEE1394: 300 case IFT_INFINIBAND: 301 case IFT_ISO88023: 302 case IFT_ISO88024: 303 case IFT_L2VLAN: 304 case IFT_BRIDGE: 305 return (1); 306 default: 307 return (0); 308 } 309 } 310 311 /* 312 * Set an individual arp entry 313 */ 314 static int 315 set(int argc, char **argv) 316 { 317 struct sockaddr_in *dst; /* what are we looking for */ 318 struct ether_addr *ea; 319 char *host = argv[0], *eaddr = argv[1]; 320 struct sockaddr_dl sdl_m; 321 322 argc -= 2; 323 argv += 2; 324 325 bzero(&sdl_m, sizeof(sdl_m)); 326 sdl_m.sdl_len = sizeof(sdl_m); 327 sdl_m.sdl_family = AF_LINK; 328 329 dst = getaddr(host); 330 if (dst == NULL) 331 return (1); 332 while (argc-- > 0) { 333 if (strcmp(argv[0], "temp") == 0) { 334 int max_age; 335 size_t len = sizeof(max_age); 336 337 if (sysctlbyname("net.link.ether.inet.max_age", 338 &max_age, &len, NULL, 0) != 0) 339 xo_err(1, "sysctlbyname"); 340 opts.expire_time = max_age; 341 } else if (strcmp(argv[0], "pub") == 0) { 342 opts.flags |= RTF_ANNOUNCE; 343 if (argc && strcmp(argv[1], "only") == 0) { 344 /* 345 * Compatibility: in pre FreeBSD 8 times 346 * the "only" keyword used to mean that 347 * an ARP entry should be announced, but 348 * not installed into routing table. 349 */ 350 argc--; argv++; 351 } 352 } else if (strcmp(argv[0], "blackhole") == 0) { 353 if (opts.flags & RTF_REJECT) { 354 xo_errx(1, "Choose one of blackhole or reject, " 355 "not both."); 356 } 357 opts.flags |= RTF_BLACKHOLE; 358 } else if (strcmp(argv[0], "reject") == 0) { 359 if (opts.flags & RTF_BLACKHOLE) { 360 xo_errx(1, "Choose one of blackhole or reject, " 361 "not both."); 362 } 363 opts.flags |= RTF_REJECT; 364 } else { 365 xo_warnx("Invalid parameter '%s'", argv[0]); 366 usage(); 367 } 368 argv++; 369 } 370 ea = (struct ether_addr *)LLADDR(&sdl_m); 371 if ((opts.flags & RTF_ANNOUNCE) && !strcmp(eaddr, "auto")) { 372 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) { 373 xo_warnx("no interface found for %s", 374 inet_ntoa(dst->sin_addr)); 375 return (1); 376 } 377 sdl_m.sdl_alen = ETHER_ADDR_LEN; 378 } else { 379 struct ether_addr *ea1 = ether_aton(eaddr); 380 381 if (ea1 == NULL) { 382 xo_warnx("invalid Ethernet address '%s'", eaddr); 383 return (1); 384 } else { 385 *ea = *ea1; 386 sdl_m.sdl_alen = ETHER_ADDR_LEN; 387 } 388 } 389 #ifndef WITHOUT_NETLINK 390 return (set_nl(0, dst, &sdl_m, host)); 391 #else 392 return (set_rtsock(dst, &sdl_m, host)); 393 #endif 394 } 395 396 #ifdef WITHOUT_NETLINK 397 static int 398 set_rtsock(struct sockaddr_in *dst, struct sockaddr_dl *sdl_m, char *host) 399 { 400 struct sockaddr_in *addr; 401 struct sockaddr_dl *sdl; 402 struct rt_msghdr *rtm; 403 404 /* 405 * In the case a proxy-arp entry is being added for 406 * a remote end point, the RTF_ANNOUNCE flag in the 407 * RTM_GET command is an indication to the kernel 408 * routing code that the interface associated with 409 * the prefix route covering the local end of the 410 * PPP link should be returned, on which ARP applies. 411 */ 412 rtm = rtmsg(RTM_GET, dst, NULL); 413 if (rtm == NULL) { 414 xo_warn("%s", host); 415 return (1); 416 } 417 addr = (struct sockaddr_in *)(rtm + 1); 418 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 419 420 if ((sdl->sdl_family != AF_LINK) || 421 (rtm->rtm_flags & RTF_GATEWAY) || 422 !valid_type(sdl->sdl_type)) { 423 xo_warnx("cannot intuit interface index and type for %s", host); 424 return (1); 425 } 426 sdl_m->sdl_type = sdl->sdl_type; 427 sdl_m->sdl_index = sdl->sdl_index; 428 return (rtmsg(RTM_ADD, dst, sdl_m) == NULL); 429 } 430 #endif 431 432 /* 433 * Display an individual arp entry 434 */ 435 static int 436 get(char *host) 437 { 438 struct sockaddr_in *addr; 439 int found; 440 441 addr = getaddr(host); 442 if (addr == NULL) 443 return (1); 444 445 xo_set_version(ARP_XO_VERSION); 446 xo_open_container("arp"); 447 xo_open_list("arp-cache"); 448 449 found = print_entries(opts.rifindex, addr->sin_addr); 450 451 if (found == 0) { 452 xo_emit("{d:hostname/%s} ({d:ip-address/%s}) -- no entry", 453 host, inet_ntoa(addr->sin_addr)); 454 if (opts.rifname) 455 xo_emit(" on {d:interface/%s}", opts.rifname); 456 xo_emit("\n"); 457 } 458 459 xo_close_list("arp-cache"); 460 xo_close_container("arp"); 461 xo_finish(); 462 463 return (found == 0); 464 } 465 466 /* 467 * Delete an arp entry 468 */ 469 #ifdef WITHOUT_NETLINK 470 static int 471 delete_rtsock(char *host) 472 { 473 struct sockaddr_in *addr, *dst; 474 struct rt_msghdr *rtm; 475 struct sockaddr_dl *sdl; 476 477 dst = getaddr(host); 478 if (dst == NULL) 479 return (1); 480 481 /* 482 * Perform a regular entry delete first. 483 */ 484 opts.flags &= ~RTF_ANNOUNCE; 485 486 for (;;) { /* try twice */ 487 rtm = rtmsg(RTM_GET, dst, NULL); 488 if (rtm == NULL) { 489 xo_warn("%s", host); 490 return (1); 491 } 492 addr = (struct sockaddr_in *)(rtm + 1); 493 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 494 495 /* 496 * With the new L2/L3 restructure, the route 497 * returned is a prefix route. The important 498 * piece of information from the previous 499 * RTM_GET is the interface index. In the 500 * case of ECMP, the kernel will traverse 501 * the route group for the given entry. 502 */ 503 if (sdl->sdl_family == AF_LINK && 504 !(rtm->rtm_flags & RTF_GATEWAY) && 505 valid_type(sdl->sdl_type) ) { 506 addr->sin_addr.s_addr = dst->sin_addr.s_addr; 507 break; 508 } 509 510 /* 511 * Regular entry delete failed, now check if there 512 * is a proxy-arp entry to remove. 513 */ 514 if (opts.flags & RTF_ANNOUNCE) { 515 xo_warnx("delete: cannot locate %s", host); 516 return (1); 517 } 518 519 opts.flags |= RTF_ANNOUNCE; 520 } 521 rtm->rtm_flags |= RTF_LLDATA; 522 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 523 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 524 return (0); 525 } 526 return (1); 527 } 528 #endif 529 530 static int 531 delete(char *host) 532 { 533 #ifdef WITHOUT_NETLINK 534 return (delete_rtsock(host)); 535 #else 536 return (delete_nl(0, host)); 537 #endif 538 } 539 540 541 /* 542 * Search the arp table and do some action on matching entries 543 */ 544 static int 545 search(u_long addr, action_fn *action) 546 { 547 int mib[6]; 548 size_t needed; 549 char *lim, *buf, *next; 550 struct rt_msghdr *rtm; 551 struct sockaddr_in *sin2; 552 struct sockaddr_dl *sdl; 553 int st, found_entry = 0; 554 555 mib[0] = CTL_NET; 556 mib[1] = PF_ROUTE; 557 mib[2] = 0; 558 mib[3] = AF_INET; 559 mib[4] = NET_RT_FLAGS; 560 #ifdef RTF_LLINFO 561 mib[5] = RTF_LLINFO; 562 #else 563 mib[5] = 0; 564 #endif 565 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 566 xo_err(1, "route-sysctl-estimate"); 567 if (needed == 0) /* empty table */ 568 return 0; 569 buf = NULL; 570 for (;;) { 571 buf = reallocf(buf, needed); 572 if (buf == NULL) 573 xo_errx(1, "could not reallocate memory"); 574 st = sysctl(mib, 6, buf, &needed, NULL, 0); 575 if (st == 0 || errno != ENOMEM) 576 break; 577 needed += needed / 8; 578 } 579 if (st == -1) 580 xo_err(1, "actual retrieval of routing table"); 581 lim = buf + needed; 582 for (next = buf; next < lim; next += rtm->rtm_msglen) { 583 rtm = (struct rt_msghdr *)next; 584 sin2 = (struct sockaddr_in *)(rtm + 1); 585 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 586 if (opts.rifindex && 587 (opts.rifindex != sdl->sdl_index)) 588 continue; 589 if (addr && 590 (addr != sin2->sin_addr.s_addr)) 591 continue; 592 found_entry = 1; 593 (*action)(sdl, sin2, rtm); 594 } 595 free(buf); 596 return (found_entry); 597 } 598 599 /* 600 * Display an arp entry 601 */ 602 603 static void 604 print_entry(struct sockaddr_dl *sdl, 605 struct sockaddr_in *addr, struct rt_msghdr *rtm) 606 { 607 const char *host; 608 struct hostent *hp; 609 struct if_nameindex *p; 610 611 if (ifnameindex == NULL) 612 if ((ifnameindex = if_nameindex()) == NULL) 613 xo_err(1, "cannot retrieve interface names"); 614 615 xo_open_instance("arp-cache"); 616 617 if (!opts.nflag) 618 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 619 sizeof addr->sin_addr, AF_INET); 620 else 621 hp = 0; 622 if (hp) 623 host = hp->h_name; 624 else { 625 host = "?"; 626 if (h_errno == TRY_AGAIN) 627 opts.nflag = true; 628 } 629 xo_emit("{:hostname/%s} ({:ip-address/%s}) at ", host, 630 inet_ntoa(addr->sin_addr)); 631 if (sdl->sdl_alen) { 632 if ((sdl->sdl_type == IFT_ETHER || 633 sdl->sdl_type == IFT_L2VLAN || 634 sdl->sdl_type == IFT_BRIDGE) && 635 sdl->sdl_alen == ETHER_ADDR_LEN) 636 xo_emit("{:mac-address/%s}", 637 ether_ntoa((struct ether_addr *)LLADDR(sdl))); 638 else { 639 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 640 641 xo_emit("{:mac-address/%s}", link_ntoa(sdl) + n); 642 } 643 } else 644 xo_emit("{d:/(incomplete)}{en:incomplete/true}"); 645 646 for (p = ifnameindex; p && p->if_index && p->if_name; p++) { 647 if (p->if_index == sdl->sdl_index) { 648 xo_emit(" on {:interface/%s}", p->if_name); 649 break; 650 } 651 } 652 653 if (rtm->rtm_rmx.rmx_expire == 0) 654 xo_emit("{d:/ permanent}{en:permanent/true}"); 655 else { 656 static struct timespec tp; 657 time_t expire_time = 0; 658 659 if (tp.tv_sec == 0) 660 clock_gettime(CLOCK_MONOTONIC, &tp); 661 if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0) 662 xo_emit(" expires in {:expires/%d} seconds", 663 (int)expire_time); 664 else 665 xo_emit("{d:/ expired}{en:expired/true}"); 666 } 667 668 if (rtm->rtm_flags & RTF_ANNOUNCE) 669 xo_emit("{d:/ published}{en:published/true}"); 670 671 switch(sdl->sdl_type) { 672 case IFT_ETHER: 673 xo_emit(" [{:type/ethernet}]"); 674 break; 675 case IFT_FDDI: 676 xo_emit(" [{:type/fddi}]"); 677 break; 678 case IFT_ATM: 679 xo_emit(" [{:type/atm}]"); 680 break; 681 case IFT_L2VLAN: 682 xo_emit(" [{:type/vlan}]"); 683 break; 684 case IFT_IEEE1394: 685 xo_emit(" [{:type/firewire}]"); 686 break; 687 case IFT_BRIDGE: 688 xo_emit(" [{:type/bridge}]"); 689 break; 690 case IFT_INFINIBAND: 691 xo_emit(" [{:type/infiniband}]"); 692 break; 693 default: 694 break; 695 } 696 697 xo_emit("\n"); 698 699 xo_close_instance("arp-cache"); 700 } 701 702 static int 703 print_entries(uint32_t ifindex, struct in_addr addr) 704 { 705 #ifndef WITHOUT_NETLINK 706 return (print_entries_nl(ifindex, addr)); 707 #else 708 return (search(addr.s_addr, print_entry)); 709 #endif 710 } 711 712 713 /* 714 * Nuke an arp entry 715 */ 716 static void 717 nuke_entry(struct sockaddr_dl *sdl __unused, 718 struct sockaddr_in *addr, struct rt_msghdr *rtm) 719 { 720 char ip[20]; 721 722 if (rtm->rtm_flags & RTF_PINNED) 723 return; 724 725 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); 726 delete(ip); 727 } 728 729 static void 730 nuke_entries(uint32_t ifindex, struct in_addr addr) 731 { 732 search(addr.s_addr, nuke_entry); 733 } 734 735 static void 736 usage(void) 737 { 738 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 739 "usage: arp [-n] [-i interface] hostname", 740 " arp [-n] [-i interface] -a", 741 " arp -d hostname [pub]", 742 " arp -d [-i interface] -a", 743 " arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 744 " arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 745 " arp -f filename"); 746 exit(1); 747 } 748 749 static struct rt_msghdr * 750 rtmsg(int cmd, struct sockaddr_in *dst, struct sockaddr_dl *sdl) 751 { 752 static int seq; 753 int rlen; 754 int l; 755 static int s = -1; 756 static pid_t pid; 757 758 static struct { 759 struct rt_msghdr m_rtm; 760 char m_space[512]; 761 } m_rtmsg; 762 763 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 764 char *cp = m_rtmsg.m_space; 765 766 if (s < 0) { /* first time: open socket, get pid */ 767 s = socket(PF_ROUTE, SOCK_RAW, 0); 768 if (s < 0) 769 xo_err(1, "socket"); 770 pid = getpid(); 771 } 772 773 errno = 0; 774 /* 775 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer 776 * appropriately. 777 */ 778 if (cmd == RTM_DELETE) 779 goto doit; 780 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 781 rtm->rtm_flags = opts.flags; 782 rtm->rtm_version = RTM_VERSION; 783 784 switch (cmd) { 785 default: 786 xo_errx(1, "internal wrong cmd"); 787 case RTM_ADD: 788 rtm->rtm_addrs |= RTA_GATEWAY; 789 if (opts.expire_time != 0) { 790 struct timespec tp; 791 792 clock_gettime(CLOCK_MONOTONIC, &tp); 793 rtm->rtm_rmx.rmx_expire = opts.expire_time + tp.tv_sec; 794 } 795 rtm->rtm_inits = RTV_EXPIRE; 796 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 797 /* FALLTHROUGH */ 798 case RTM_GET: 799 rtm->rtm_addrs |= RTA_DST; 800 } 801 #define NEXTADDR(w, s) \ 802 do { \ 803 if ((s) != NULL && rtm->rtm_addrs & (w)) { \ 804 bcopy((s), cp, sizeof(*(s))); \ 805 cp += SA_SIZE(s); \ 806 } \ 807 } while (0) 808 809 NEXTADDR(RTA_DST, dst); 810 NEXTADDR(RTA_GATEWAY, sdl); 811 812 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 813 doit: 814 l = rtm->rtm_msglen; 815 rtm->rtm_seq = ++seq; 816 rtm->rtm_type = cmd; 817 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 818 if (errno != ESRCH || cmd != RTM_DELETE) { 819 xo_warn("writing to routing socket"); 820 return (NULL); 821 } 822 } 823 do { 824 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 825 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || 826 rtm->rtm_pid != pid)); 827 if (l < 0) 828 xo_warn("read from routing socket"); 829 return (rtm); 830 } 831 832 /* 833 * get_ether_addr - get the hardware address of an interface on the 834 * the same subnet as ipaddr. 835 */ 836 static int 837 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr) 838 { 839 struct ifaddrs *ifa, *ifd, *ifas = NULL; 840 in_addr_t ina, mask; 841 struct sockaddr_dl *dla; 842 int retval = 0; 843 844 /* 845 * Scan through looking for an interface with an Internet 846 * address on the same subnet as `ipaddr'. 847 */ 848 if (getifaddrs(&ifas) < 0) { 849 xo_warnx("getifaddrs"); 850 goto done; 851 } 852 853 for (ifa = ifas; ifa != NULL; ifa = ifa->ifa_next) { 854 if (ifa->ifa_addr == NULL || ifa->ifa_netmask == NULL) 855 continue; 856 if (ifa->ifa_addr->sa_family != AF_INET) 857 continue; 858 /* 859 * Check that the interface is up, 860 * and not point-to-point or loopback. 861 */ 862 if ((ifa->ifa_flags & 863 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 864 IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) 865 continue; 866 /* Get its netmask and check that it's on the right subnet. */ 867 mask = ((struct sockaddr_in *) 868 ifa->ifa_netmask)->sin_addr.s_addr; 869 ina = ((struct sockaddr_in *) 870 ifa->ifa_addr)->sin_addr.s_addr; 871 if ((ipaddr & mask) == (ina & mask)) 872 break; /* ok, we got it! */ 873 } 874 if (ifa == NULL) 875 goto done; 876 877 /* 878 * Now scan through again looking for a link-level address 879 * for this interface. 880 */ 881 for (ifd = ifas; ifd != NULL; ifd = ifd->ifa_next) { 882 if (ifd->ifa_addr == NULL) 883 continue; 884 if (strcmp(ifa->ifa_name, ifd->ifa_name) == 0 && 885 ifd->ifa_addr->sa_family == AF_LINK) 886 break; 887 } 888 if (ifd == NULL) 889 goto done; 890 /* 891 * Found the link-level address - copy it out 892 */ 893 dla = (struct sockaddr_dl *)ifd->ifa_addr; 894 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 895 printf("using interface %s for proxy with address %s\n", ifa->ifa_name, 896 ether_ntoa(hwaddr)); 897 retval = dla->sdl_alen; 898 done: 899 if (ifas != NULL) 900 freeifaddrs(ifas); 901 return (retval); 902 } 903