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 __FBSDID("$FreeBSD$"); 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/sockio.h> 57 #include <sys/sysctl.h> 58 #include <sys/ioctl.h> 59 #include <sys/time.h> 60 61 #include <net/if.h> 62 #include <net/if_dl.h> 63 #include <net/if_types.h> 64 #include <net/route.h> 65 66 #include <netinet/in.h> 67 #include <netinet/if_ether.h> 68 69 #include <arpa/inet.h> 70 71 #include <ctype.h> 72 #include <err.h> 73 #include <errno.h> 74 #include <netdb.h> 75 #include <nlist.h> 76 #include <paths.h> 77 #include <stdio.h> 78 #include <stdlib.h> 79 #include <string.h> 80 #include <strings.h> 81 #include <unistd.h> 82 #include <libxo/xo.h> 83 84 typedef void (action_fn)(struct sockaddr_dl *sdl, struct sockaddr_in *s_in, 85 struct rt_msghdr *rtm); 86 87 static int search(u_long addr, action_fn *action); 88 static action_fn print_entry; 89 static action_fn nuke_entry; 90 91 static int delete(char *host); 92 static void usage(void); 93 static int set(int argc, char **argv); 94 static int get(char *host); 95 static int file(char *name); 96 static struct rt_msghdr *rtmsg(int cmd, 97 struct sockaddr_in *dst, struct sockaddr_dl *sdl); 98 static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 99 static struct sockaddr_in *getaddr(char *host); 100 static int valid_type(int type); 101 102 static int nflag; /* no reverse dns lookups */ 103 static char *rifname; 104 105 static time_t expire_time; 106 static int flags, doing_proxy; 107 108 struct if_nameindex *ifnameindex; 109 110 /* which function we're supposed to do */ 111 #define F_GET 1 112 #define F_SET 2 113 #define F_FILESET 3 114 #define F_REPLACE 4 115 #define F_DELETE 5 116 117 #define SETFUNC(f) { if (func) usage(); func = (f); } 118 119 #define ARP_XO_VERSION "1" 120 121 int 122 main(int argc, char *argv[]) 123 { 124 int ch, func = 0; 125 int rtn = 0; 126 int aflag = 0; /* do it for all entries */ 127 128 argc = xo_parse_args(argc, argv); 129 if (argc < 0) 130 exit(1); 131 132 while ((ch = getopt(argc, argv, "andfsSi:")) != -1) 133 switch(ch) { 134 case 'a': 135 aflag = 1; 136 break; 137 case 'd': 138 SETFUNC(F_DELETE); 139 break; 140 case 'n': 141 nflag = 1; 142 break; 143 case 'S': 144 SETFUNC(F_REPLACE); 145 break; 146 case 's': 147 SETFUNC(F_SET); 148 break; 149 case 'f' : 150 SETFUNC(F_FILESET); 151 break; 152 case 'i': 153 rifname = optarg; 154 break; 155 case '?': 156 default: 157 usage(); 158 } 159 argc -= optind; 160 argv += optind; 161 162 if (!func) 163 func = F_GET; 164 if (rifname) { 165 if (func != F_GET && !(func == F_DELETE && aflag)) 166 xo_errx(1, "-i not applicable to this operation"); 167 if (if_nametoindex(rifname) == 0) { 168 if (errno == ENXIO) 169 xo_errx(1, "interface %s does not exist", 170 rifname); 171 else 172 xo_err(1, "if_nametoindex(%s)", rifname); 173 } 174 } 175 switch (func) { 176 case F_GET: 177 if (aflag) { 178 if (argc != 0) 179 usage(); 180 181 xo_set_version(ARP_XO_VERSION); 182 xo_open_container("arp"); 183 xo_open_list("arp-cache"); 184 185 search(0, print_entry); 186 187 xo_close_list("arp-cache"); 188 xo_close_container("arp"); 189 xo_finish(); 190 } else { 191 if (argc != 1) 192 usage(); 193 rtn = get(argv[0]); 194 } 195 break; 196 case F_SET: 197 case F_REPLACE: 198 if (argc < 2 || argc > 6) 199 usage(); 200 if (func == F_REPLACE) 201 (void)delete(argv[0]); 202 rtn = set(argc, argv) ? 1 : 0; 203 break; 204 case F_DELETE: 205 if (aflag) { 206 if (argc != 0) 207 usage(); 208 search(0, nuke_entry); 209 } else { 210 if (argc != 1) 211 usage(); 212 rtn = delete(argv[0]); 213 } 214 break; 215 case F_FILESET: 216 if (argc != 1) 217 usage(); 218 rtn = file(argv[0]); 219 break; 220 } 221 222 if (ifnameindex != NULL) 223 if_freenameindex(ifnameindex); 224 225 return (rtn); 226 } 227 228 /* 229 * Process a file to set standard arp entries 230 */ 231 static int 232 file(char *name) 233 { 234 FILE *fp; 235 int i, retval; 236 char line[100], arg[5][50], *args[5], *p; 237 238 if ((fp = fopen(name, "r")) == NULL) 239 xo_err(1, "cannot open %s", name); 240 args[0] = &arg[0][0]; 241 args[1] = &arg[1][0]; 242 args[2] = &arg[2][0]; 243 args[3] = &arg[3][0]; 244 args[4] = &arg[4][0]; 245 retval = 0; 246 while(fgets(line, sizeof(line), fp) != NULL) { 247 if ((p = strchr(line, '#')) != NULL) 248 *p = '\0'; 249 for (p = line; isblank(*p); p++); 250 if (*p == '\n' || *p == '\0') 251 continue; 252 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1], 253 arg[2], arg[3], arg[4]); 254 if (i < 2) { 255 xo_warnx("bad line: %s", line); 256 retval = 1; 257 continue; 258 } 259 if (set(i, args)) 260 retval = 1; 261 } 262 fclose(fp); 263 return (retval); 264 } 265 266 /* 267 * Given a hostname, fills up a (static) struct sockaddr_in with 268 * the address of the host and returns a pointer to the 269 * structure. 270 */ 271 static struct sockaddr_in * 272 getaddr(char *host) 273 { 274 struct hostent *hp; 275 static struct sockaddr_in reply; 276 277 bzero(&reply, sizeof(reply)); 278 reply.sin_len = sizeof(reply); 279 reply.sin_family = AF_INET; 280 reply.sin_addr.s_addr = inet_addr(host); 281 if (reply.sin_addr.s_addr == INADDR_NONE) { 282 if (!(hp = gethostbyname(host))) { 283 xo_warnx("%s: %s", host, hstrerror(h_errno)); 284 return (NULL); 285 } 286 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr, 287 sizeof reply.sin_addr); 288 } 289 return (&reply); 290 } 291 292 /* 293 * Returns true if the type is a valid one for ARP. 294 */ 295 static int 296 valid_type(int type) 297 { 298 299 switch (type) { 300 case IFT_ETHER: 301 case IFT_FDDI: 302 case IFT_INFINIBAND: 303 case IFT_ISO88023: 304 case IFT_ISO88024: 305 case IFT_L2VLAN: 306 case IFT_BRIDGE: 307 return (1); 308 default: 309 return (0); 310 } 311 } 312 313 /* 314 * Set an individual arp entry 315 */ 316 static int 317 set(int argc, char **argv) 318 { 319 struct sockaddr_in *addr; 320 struct sockaddr_in *dst; /* what are we looking for */ 321 struct sockaddr_dl *sdl; 322 struct rt_msghdr *rtm; 323 struct ether_addr *ea; 324 char *host = argv[0], *eaddr = argv[1]; 325 struct sockaddr_dl sdl_m; 326 327 argc -= 2; 328 argv += 2; 329 330 bzero(&sdl_m, sizeof(sdl_m)); 331 sdl_m.sdl_len = sizeof(sdl_m); 332 sdl_m.sdl_family = AF_LINK; 333 334 dst = getaddr(host); 335 if (dst == NULL) 336 return (1); 337 doing_proxy = flags = expire_time = 0; 338 while (argc-- > 0) { 339 if (strcmp(argv[0], "temp") == 0) { 340 struct timespec tp; 341 int max_age; 342 size_t len = sizeof(max_age); 343 344 clock_gettime(CLOCK_MONOTONIC, &tp); 345 if (sysctlbyname("net.link.ether.inet.max_age", 346 &max_age, &len, NULL, 0) != 0) 347 xo_err(1, "sysctlbyname"); 348 expire_time = tp.tv_sec + max_age; 349 } else if (strcmp(argv[0], "pub") == 0) { 350 flags |= RTF_ANNOUNCE; 351 doing_proxy = 1; 352 if (argc && strcmp(argv[1], "only") == 0) { 353 /* 354 * Compatibility: in pre FreeBSD 8 times 355 * the "only" keyword used to mean that 356 * an ARP entry should be announced, but 357 * not installed into routing table. 358 */ 359 argc--; argv++; 360 } 361 } else if (strcmp(argv[0], "blackhole") == 0) { 362 if (flags & RTF_REJECT) { 363 xo_errx(1, "Choose one of blackhole or reject, " 364 "not both."); 365 } 366 flags |= RTF_BLACKHOLE; 367 } else if (strcmp(argv[0], "reject") == 0) { 368 if (flags & RTF_BLACKHOLE) { 369 xo_errx(1, "Choose one of blackhole or reject, " 370 "not both."); 371 } 372 flags |= RTF_REJECT; 373 } else { 374 xo_warnx("Invalid parameter '%s'", argv[0]); 375 usage(); 376 } 377 argv++; 378 } 379 ea = (struct ether_addr *)LLADDR(&sdl_m); 380 if (doing_proxy && !strcmp(eaddr, "auto")) { 381 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) { 382 xo_warnx("no interface found for %s", 383 inet_ntoa(dst->sin_addr)); 384 return (1); 385 } 386 sdl_m.sdl_alen = ETHER_ADDR_LEN; 387 } else { 388 struct ether_addr *ea1 = ether_aton(eaddr); 389 390 if (ea1 == NULL) { 391 xo_warnx("invalid Ethernet address '%s'", eaddr); 392 return (1); 393 } else { 394 *ea = *ea1; 395 sdl_m.sdl_alen = ETHER_ADDR_LEN; 396 } 397 } 398 399 /* 400 * In the case a proxy-arp entry is being added for 401 * a remote end point, the RTF_ANNOUNCE flag in the 402 * RTM_GET command is an indication to the kernel 403 * routing code that the interface associated with 404 * the prefix route covering the local end of the 405 * PPP link should be returned, on which ARP applies. 406 */ 407 rtm = rtmsg(RTM_GET, dst, NULL); 408 if (rtm == NULL) { 409 xo_warn("%s", host); 410 return (1); 411 } 412 addr = (struct sockaddr_in *)(rtm + 1); 413 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 414 415 if ((sdl->sdl_family != AF_LINK) || 416 (rtm->rtm_flags & RTF_GATEWAY) || 417 !valid_type(sdl->sdl_type)) { 418 xo_warnx("cannot intuit interface index and type for %s", host); 419 return (1); 420 } 421 sdl_m.sdl_type = sdl->sdl_type; 422 sdl_m.sdl_index = sdl->sdl_index; 423 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL); 424 } 425 426 /* 427 * Display an individual arp entry 428 */ 429 static int 430 get(char *host) 431 { 432 struct sockaddr_in *addr; 433 int found; 434 435 addr = getaddr(host); 436 if (addr == NULL) 437 return (1); 438 439 xo_set_version(ARP_XO_VERSION); 440 xo_open_container("arp"); 441 xo_open_list("arp-cache"); 442 443 found = search(addr->sin_addr.s_addr, print_entry); 444 445 if (found == 0) { 446 xo_emit("{d:hostname/%s} ({d:ip-address/%s}) -- no entry", 447 host, inet_ntoa(addr->sin_addr)); 448 if (rifname) 449 xo_emit(" on {d:interface/%s}", rifname); 450 xo_emit("\n"); 451 } 452 453 xo_close_list("arp-cache"); 454 xo_close_container("arp"); 455 xo_finish(); 456 457 return (found == 0); 458 } 459 460 /* 461 * Delete an arp entry 462 */ 463 static int 464 delete(char *host) 465 { 466 struct sockaddr_in *addr, *dst; 467 struct rt_msghdr *rtm; 468 struct sockaddr_dl *sdl; 469 470 dst = getaddr(host); 471 if (dst == NULL) 472 return (1); 473 474 /* 475 * Perform a regular entry delete first. 476 */ 477 flags &= ~RTF_ANNOUNCE; 478 479 for (;;) { /* try twice */ 480 rtm = rtmsg(RTM_GET, dst, NULL); 481 if (rtm == NULL) { 482 xo_warn("%s", host); 483 return (1); 484 } 485 addr = (struct sockaddr_in *)(rtm + 1); 486 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 487 488 /* 489 * With the new L2/L3 restructure, the route 490 * returned is a prefix route. The important 491 * piece of information from the previous 492 * RTM_GET is the interface index. In the 493 * case of ECMP, the kernel will traverse 494 * the route group for the given entry. 495 */ 496 if (sdl->sdl_family == AF_LINK && 497 !(rtm->rtm_flags & RTF_GATEWAY) && 498 valid_type(sdl->sdl_type) ) { 499 addr->sin_addr.s_addr = dst->sin_addr.s_addr; 500 break; 501 } 502 503 /* 504 * Regular entry delete failed, now check if there 505 * is a proxy-arp entry to remove. 506 */ 507 if (flags & RTF_ANNOUNCE) { 508 xo_warnx("delete: cannot locate %s", host); 509 return (1); 510 } 511 512 flags |= RTF_ANNOUNCE; 513 } 514 rtm->rtm_flags |= RTF_LLDATA; 515 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 516 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 517 return (0); 518 } 519 return (1); 520 } 521 522 523 /* 524 * Search the arp table and do some action on matching entries 525 */ 526 static int 527 search(u_long addr, action_fn *action) 528 { 529 int mib[6]; 530 size_t needed; 531 char *lim, *buf, *next; 532 struct rt_msghdr *rtm; 533 struct sockaddr_in *sin2; 534 struct sockaddr_dl *sdl; 535 char ifname[IF_NAMESIZE]; 536 int st, found_entry = 0; 537 538 mib[0] = CTL_NET; 539 mib[1] = PF_ROUTE; 540 mib[2] = 0; 541 mib[3] = AF_INET; 542 mib[4] = NET_RT_FLAGS; 543 #ifdef RTF_LLINFO 544 mib[5] = RTF_LLINFO; 545 #else 546 mib[5] = 0; 547 #endif 548 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 549 xo_err(1, "route-sysctl-estimate"); 550 if (needed == 0) /* empty table */ 551 return 0; 552 buf = NULL; 553 for (;;) { 554 buf = reallocf(buf, needed); 555 if (buf == NULL) 556 xo_errx(1, "could not reallocate memory"); 557 st = sysctl(mib, 6, buf, &needed, NULL, 0); 558 if (st == 0 || errno != ENOMEM) 559 break; 560 needed += needed / 8; 561 } 562 if (st == -1) 563 xo_err(1, "actual retrieval of routing table"); 564 lim = buf + needed; 565 for (next = buf; next < lim; next += rtm->rtm_msglen) { 566 rtm = (struct rt_msghdr *)next; 567 sin2 = (struct sockaddr_in *)(rtm + 1); 568 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 569 if (rifname && if_indextoname(sdl->sdl_index, ifname) && 570 strcmp(ifname, rifname)) 571 continue; 572 if (addr) { 573 if (addr != sin2->sin_addr.s_addr) 574 continue; 575 found_entry = 1; 576 } 577 (*action)(sdl, sin2, rtm); 578 } 579 free(buf); 580 return (found_entry); 581 } 582 583 /* 584 * Display an arp entry 585 */ 586 587 static void 588 print_entry(struct sockaddr_dl *sdl, 589 struct sockaddr_in *addr, struct rt_msghdr *rtm) 590 { 591 const char *host; 592 struct hostent *hp; 593 struct if_nameindex *p; 594 595 if (ifnameindex == NULL) 596 if ((ifnameindex = if_nameindex()) == NULL) 597 xo_err(1, "cannot retrieve interface names"); 598 599 xo_open_instance("arp-cache"); 600 601 if (nflag == 0) 602 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 603 sizeof addr->sin_addr, AF_INET); 604 else 605 hp = 0; 606 if (hp) 607 host = hp->h_name; 608 else { 609 host = "?"; 610 if (h_errno == TRY_AGAIN) 611 nflag = 1; 612 } 613 xo_emit("{:hostname/%s} ({:ip-address/%s}) at ", host, 614 inet_ntoa(addr->sin_addr)); 615 if (sdl->sdl_alen) { 616 if ((sdl->sdl_type == IFT_ETHER || 617 sdl->sdl_type == IFT_L2VLAN || 618 sdl->sdl_type == IFT_BRIDGE) && 619 sdl->sdl_alen == ETHER_ADDR_LEN) 620 xo_emit("{:mac-address/%s}", 621 ether_ntoa((struct ether_addr *)LLADDR(sdl))); 622 else { 623 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 624 625 xo_emit("{:mac-address/%s}", link_ntoa(sdl) + n); 626 } 627 } else 628 xo_emit("{d:/(incomplete)}{en:incomplete/true}"); 629 630 for (p = ifnameindex; p && ifnameindex->if_index && 631 ifnameindex->if_name; p++) { 632 if (p->if_index == sdl->sdl_index) { 633 xo_emit(" on {:interface/%s}", p->if_name); 634 break; 635 } 636 } 637 638 if (rtm->rtm_rmx.rmx_expire == 0) 639 xo_emit("{d:/ permanent}{en:permanent/true}"); 640 else { 641 static struct timespec tp; 642 if (tp.tv_sec == 0) 643 clock_gettime(CLOCK_MONOTONIC, &tp); 644 if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0) 645 xo_emit(" expires in {:expires/%d} seconds", 646 (int)expire_time); 647 else 648 xo_emit("{d:/ expired}{en:expired/true}"); 649 } 650 651 if (rtm->rtm_flags & RTF_ANNOUNCE) 652 xo_emit("{d:/ published}{en:published/true}"); 653 654 switch(sdl->sdl_type) { 655 case IFT_ETHER: 656 xo_emit(" [{:type/ethernet}]"); 657 break; 658 case IFT_FDDI: 659 xo_emit(" [{:type/fddi}]"); 660 break; 661 case IFT_ATM: 662 xo_emit(" [{:type/atm}]"); 663 break; 664 case IFT_L2VLAN: 665 xo_emit(" [{:type/vlan}]"); 666 break; 667 case IFT_IEEE1394: 668 xo_emit(" [{:type/firewire}]"); 669 break; 670 case IFT_BRIDGE: 671 xo_emit(" [{:type/bridge}]"); 672 break; 673 case IFT_INFINIBAND: 674 xo_emit(" [{:type/infiniband}]"); 675 break; 676 default: 677 break; 678 } 679 680 xo_emit("\n"); 681 682 xo_close_instance("arp-cache"); 683 } 684 685 /* 686 * Nuke an arp entry 687 */ 688 static void 689 nuke_entry(struct sockaddr_dl *sdl __unused, 690 struct sockaddr_in *addr, struct rt_msghdr *rtm) 691 { 692 char ip[20]; 693 694 if (rtm->rtm_flags & RTF_PINNED) 695 return; 696 697 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); 698 delete(ip); 699 } 700 701 static void 702 usage(void) 703 { 704 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 705 "usage: arp [-n] [-i interface] hostname", 706 " arp [-n] [-i interface] -a", 707 " arp -d hostname [pub]", 708 " arp -d [-i interface] -a", 709 " arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 710 " arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 711 " arp -f filename"); 712 exit(1); 713 } 714 715 static struct rt_msghdr * 716 rtmsg(int cmd, struct sockaddr_in *dst, struct sockaddr_dl *sdl) 717 { 718 static int seq; 719 int rlen; 720 int l; 721 struct sockaddr_in so_mask, *som = &so_mask; 722 static int s = -1; 723 static pid_t pid; 724 725 static struct { 726 struct rt_msghdr m_rtm; 727 char m_space[512]; 728 } m_rtmsg; 729 730 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 731 char *cp = m_rtmsg.m_space; 732 733 if (s < 0) { /* first time: open socket, get pid */ 734 s = socket(PF_ROUTE, SOCK_RAW, 0); 735 if (s < 0) 736 xo_err(1, "socket"); 737 pid = getpid(); 738 } 739 bzero(&so_mask, sizeof(so_mask)); 740 so_mask.sin_len = 8; 741 so_mask.sin_addr.s_addr = 0xffffffff; 742 743 errno = 0; 744 /* 745 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer 746 * appropriately. 747 */ 748 if (cmd == RTM_DELETE) 749 goto doit; 750 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 751 rtm->rtm_flags = flags; 752 rtm->rtm_version = RTM_VERSION; 753 754 switch (cmd) { 755 default: 756 xo_errx(1, "internal wrong cmd"); 757 case RTM_ADD: 758 rtm->rtm_addrs |= RTA_GATEWAY; 759 rtm->rtm_rmx.rmx_expire = expire_time; 760 rtm->rtm_inits = RTV_EXPIRE; 761 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 762 if (doing_proxy) { 763 rtm->rtm_addrs |= RTA_NETMASK; 764 rtm->rtm_flags &= ~RTF_HOST; 765 } 766 /* FALLTHROUGH */ 767 case RTM_GET: 768 rtm->rtm_addrs |= RTA_DST; 769 } 770 #define NEXTADDR(w, s) \ 771 do { \ 772 if ((s) != NULL && rtm->rtm_addrs & (w)) { \ 773 bcopy((s), cp, sizeof(*(s))); \ 774 cp += SA_SIZE(s); \ 775 } \ 776 } while (0) 777 778 NEXTADDR(RTA_DST, dst); 779 NEXTADDR(RTA_GATEWAY, sdl); 780 NEXTADDR(RTA_NETMASK, som); 781 782 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 783 doit: 784 l = rtm->rtm_msglen; 785 rtm->rtm_seq = ++seq; 786 rtm->rtm_type = cmd; 787 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 788 if (errno != ESRCH || cmd != RTM_DELETE) { 789 xo_warn("writing to routing socket"); 790 return (NULL); 791 } 792 } 793 do { 794 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 795 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || 796 rtm->rtm_pid != pid)); 797 if (l < 0) 798 xo_warn("read from routing socket"); 799 return (rtm); 800 } 801 802 /* 803 * get_ether_addr - get the hardware address of an interface on the 804 * the same subnet as ipaddr. 805 */ 806 #define MAX_IFS 32 807 808 static int 809 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr) 810 { 811 struct ifreq *ifr, *ifend, *ifp; 812 in_addr_t ina, mask; 813 struct sockaddr_dl *dla; 814 struct ifreq ifreq; 815 struct ifconf ifc; 816 struct ifreq ifs[MAX_IFS]; 817 int sock; 818 int retval = 0; 819 820 sock = socket(AF_INET, SOCK_DGRAM, 0); 821 if (sock < 0) 822 xo_err(1, "socket"); 823 824 ifc.ifc_len = sizeof(ifs); 825 ifc.ifc_req = ifs; 826 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) { 827 xo_warnx("ioctl(SIOCGIFCONF)"); 828 goto done; 829 } 830 831 #define NEXTIFR(i) \ 832 ((struct ifreq *)((char *)&(i)->ifr_addr \ 833 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) ) 834 835 /* 836 * Scan through looking for an interface with an Internet 837 * address on the same subnet as `ipaddr'. 838 */ 839 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len); 840 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) { 841 if (ifr->ifr_addr.sa_family != AF_INET) 842 continue; 843 strncpy(ifreq.ifr_name, ifr->ifr_name, 844 sizeof(ifreq.ifr_name)); 845 ifreq.ifr_addr = ifr->ifr_addr; 846 /* 847 * Check that the interface is up, 848 * and not point-to-point or loopback. 849 */ 850 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0) 851 continue; 852 if ((ifreq.ifr_flags & 853 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 854 IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) 855 continue; 856 /* Get its netmask and check that it's on the right subnet. */ 857 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0) 858 continue; 859 mask = ((struct sockaddr_in *) 860 &ifreq.ifr_addr)->sin_addr.s_addr; 861 ina = ((struct sockaddr_in *) 862 &ifr->ifr_addr)->sin_addr.s_addr; 863 if ((ipaddr & mask) == (ina & mask)) 864 break; /* ok, we got it! */ 865 } 866 867 if (ifr >= ifend) 868 goto done; 869 870 /* 871 * Now scan through again looking for a link-level address 872 * for this interface. 873 */ 874 ifp = ifr; 875 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr)) 876 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && 877 ifr->ifr_addr.sa_family == AF_LINK) 878 break; 879 if (ifr >= ifend) 880 goto done; 881 /* 882 * Found the link-level address - copy it out 883 */ 884 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 885 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 886 printf("using interface %s for proxy with address %s\n", ifp->ifr_name, 887 ether_ntoa(hwaddr)); 888 retval = dla->sdl_alen; 889 done: 890 close(sock); 891 return (retval); 892 } 893