1 /* 2 * Copyright (c) 1984, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Sun Microsystems, Inc. 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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if 0 34 #ifndef lint 35 static char const copyright[] = 36 "@(#) Copyright (c) 1984, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 static char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94"; 42 #endif /* not lint */ 43 #endif 44 #include <sys/cdefs.h> 45 __FBSDID("$FreeBSD$"); 46 47 /* 48 * arp - display, set, and delete arp table entries 49 */ 50 51 52 #include <sys/param.h> 53 #include <sys/file.h> 54 #include <sys/socket.h> 55 #include <sys/sockio.h> 56 #include <sys/sysctl.h> 57 #include <sys/ioctl.h> 58 #include <sys/time.h> 59 60 #include <net/if.h> 61 #include <net/if_dl.h> 62 #include <net/if_types.h> 63 #include <net/route.h> 64 #include <net/iso88025.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 83 typedef void (action_fn)(struct sockaddr_dl *sdl, 84 struct sockaddr_inarp *s_in, struct rt_msghdr *rtm); 85 86 static int search(u_long addr, action_fn *action); 87 static action_fn print_entry; 88 static action_fn nuke_entry; 89 90 static int delete(char *host, int do_proxy); 91 static void usage(void); 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_inarp *dst, struct sockaddr_dl *sdl); 97 static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 98 static struct sockaddr_inarp *getaddr(char *host); 99 static int valid_type(int type); 100 101 static int nflag; /* no reverse dns lookups */ 102 static char *rifname; 103 104 static time_t expire_time; 105 static int flags, doing_proxy, proxy_only; 106 107 /* which function we're supposed to do */ 108 #define F_GET 1 109 #define F_SET 2 110 #define F_FILESET 3 111 #define F_REPLACE 4 112 #define F_DELETE 5 113 114 #define SETFUNC(f) { if (func) usage(); func = (f); } 115 116 int 117 main(int argc, char *argv[]) 118 { 119 int ch, func = 0; 120 int rtn = 0; 121 int aflag = 0; /* do it for all entries */ 122 123 while ((ch = getopt(argc, argv, "andfsSi:")) != -1) 124 switch(ch) { 125 case 'a': 126 aflag = 1; 127 break; 128 case 'd': 129 SETFUNC(F_DELETE); 130 break; 131 case 'n': 132 nflag = 1; 133 break; 134 case 'S': 135 SETFUNC(F_REPLACE); 136 break; 137 case 's': 138 SETFUNC(F_SET); 139 break; 140 case 'f' : 141 SETFUNC(F_FILESET); 142 break; 143 case 'i': 144 rifname = optarg; 145 break; 146 case '?': 147 default: 148 usage(); 149 } 150 argc -= optind; 151 argv += optind; 152 153 if (!func) 154 func = F_GET; 155 if (rifname) { 156 if (func != F_GET && !(func == F_DELETE && aflag)) 157 errx(1, "-i not applicable to this operation"); 158 if (if_nametoindex(rifname) == 0) { 159 if (errno == ENXIO) 160 errx(1, "interface %s does not exist", rifname); 161 else 162 err(1, "if_nametoindex(%s)", rifname); 163 } 164 } 165 switch (func) { 166 case F_GET: 167 if (aflag) { 168 if (argc != 0) 169 usage(); 170 search(0, print_entry); 171 } else { 172 if (argc != 1) 173 usage(); 174 rtn = get(argv[0]); 175 } 176 break; 177 case F_SET: 178 case F_REPLACE: 179 if (argc < 2 || argc > 6) 180 usage(); 181 if (func == F_REPLACE) 182 (void)delete(argv[0], 0); 183 rtn = set(argc, argv) ? 1 : 0; 184 break; 185 case F_DELETE: 186 if (aflag) { 187 if (argc != 0) 188 usage(); 189 search(0, nuke_entry); 190 } else { 191 if (argc == 2 && strncmp(argv[1], "pub", 3) == 0) 192 ch = SIN_PROXY; 193 else if (argc == 1) 194 ch = 0; 195 else 196 usage(); 197 rtn = delete(argv[0], ch); 198 } 199 break; 200 case F_FILESET: 201 if (argc != 1) 202 usage(); 203 rtn = file(argv[0]); 204 break; 205 } 206 207 return (rtn); 208 } 209 210 /* 211 * Process a file to set standard arp entries 212 */ 213 static int 214 file(char *name) 215 { 216 FILE *fp; 217 int i, retval; 218 char line[100], arg[5][50], *args[5], *p; 219 220 if ((fp = fopen(name, "r")) == NULL) 221 err(1, "cannot open %s", name); 222 args[0] = &arg[0][0]; 223 args[1] = &arg[1][0]; 224 args[2] = &arg[2][0]; 225 args[3] = &arg[3][0]; 226 args[4] = &arg[4][0]; 227 retval = 0; 228 while(fgets(line, sizeof(line), fp) != NULL) { 229 if ((p = strchr(line, '#')) != NULL) 230 *p = '\0'; 231 for (p = line; isblank(*p); p++); 232 if (*p == '\n' || *p == '\0') 233 continue; 234 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1], 235 arg[2], arg[3], arg[4]); 236 if (i < 2) { 237 warnx("bad line: %s", line); 238 retval = 1; 239 continue; 240 } 241 if (set(i, args)) 242 retval = 1; 243 } 244 fclose(fp); 245 return (retval); 246 } 247 248 /* 249 * Given a hostname, fills up a (static) struct sockaddr_inarp with 250 * the address of the host and returns a pointer to the 251 * structure. 252 */ 253 static struct sockaddr_inarp * 254 getaddr(char *host) 255 { 256 struct hostent *hp; 257 static struct sockaddr_inarp reply; 258 259 bzero(&reply, sizeof(reply)); 260 reply.sin_len = sizeof(reply); 261 reply.sin_family = AF_INET; 262 reply.sin_addr.s_addr = inet_addr(host); 263 if (reply.sin_addr.s_addr == INADDR_NONE) { 264 if (!(hp = gethostbyname(host))) { 265 warnx("%s: %s", host, hstrerror(h_errno)); 266 return (NULL); 267 } 268 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr, 269 sizeof reply.sin_addr); 270 } 271 return (&reply); 272 } 273 274 /* 275 * Returns true if the type is a valid one for ARP. 276 */ 277 static int 278 valid_type(int type) 279 { 280 281 switch (type) { 282 case IFT_ETHER: 283 case IFT_FDDI: 284 case IFT_ISO88023: 285 case IFT_ISO88024: 286 case IFT_ISO88025: 287 case IFT_L2VLAN: 288 case IFT_BRIDGE: 289 return (1); 290 default: 291 return (0); 292 } 293 } 294 295 /* 296 * Set an individual arp entry 297 */ 298 static int 299 set(int argc, char **argv) 300 { 301 struct sockaddr_inarp *addr; 302 struct sockaddr_inarp *dst; /* what are we looking for */ 303 struct sockaddr_dl *sdl; 304 struct rt_msghdr *rtm; 305 struct ether_addr *ea; 306 char *host = argv[0], *eaddr = argv[1]; 307 struct sockaddr_dl sdl_m; 308 309 argc -= 2; 310 argv += 2; 311 312 bzero(&sdl_m, sizeof(sdl_m)); 313 sdl_m.sdl_len = sizeof(sdl_m); 314 sdl_m.sdl_family = AF_LINK; 315 316 dst = getaddr(host); 317 if (dst == NULL) 318 return (1); 319 doing_proxy = flags = proxy_only = expire_time = 0; 320 while (argc-- > 0) { 321 if (strncmp(argv[0], "temp", 4) == 0) { 322 struct timespec tp; 323 int max_age; 324 size_t len = sizeof(max_age); 325 326 clock_gettime(CLOCK_MONOTONIC, &tp); 327 if (sysctlbyname("net.link.ether.inet.max_age", 328 &max_age, &len, NULL, 0) != 0) 329 err(1, "sysctlbyname"); 330 expire_time = tp.tv_sec + max_age; 331 } else if (strncmp(argv[0], "pub", 3) == 0) { 332 flags |= RTF_ANNOUNCE; 333 doing_proxy = 1; 334 if (argc && strncmp(argv[1], "only", 3) == 0) { 335 proxy_only = 1; 336 argc--; argv++; 337 } 338 } else if (strncmp(argv[0], "blackhole", 9) == 0) { 339 if (flags & RTF_REJECT) { 340 printf("Choose one of blackhole or reject, not both.\n"); 341 } 342 flags |= RTF_BLACKHOLE; 343 } else if (strncmp(argv[0], "reject", 6) == 0) { 344 if (flags & RTF_BLACKHOLE) { 345 printf("Choose one of blackhole or reject, not both.\n"); 346 } 347 flags |= RTF_REJECT; 348 } else if (strncmp(argv[0], "trail", 5) == 0) { 349 /* XXX deprecated and undocumented feature */ 350 printf("%s: Sending trailers is no longer supported\n", 351 host); 352 } 353 argv++; 354 } 355 ea = (struct ether_addr *)LLADDR(&sdl_m); 356 if (doing_proxy && !strcmp(eaddr, "auto")) { 357 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) { 358 printf("no interface found for %s\n", 359 inet_ntoa(dst->sin_addr)); 360 return (1); 361 } 362 sdl_m.sdl_alen = ETHER_ADDR_LEN; 363 } else { 364 struct ether_addr *ea1 = ether_aton(eaddr); 365 366 if (ea1 == NULL) { 367 warnx("invalid Ethernet address '%s'", eaddr); 368 return (1); 369 } else { 370 *ea = *ea1; 371 sdl_m.sdl_alen = ETHER_ADDR_LEN; 372 } 373 } 374 375 /* 376 * In the case a proxy-arp entry is being added for 377 * a remote end point, the RTF_ANNOUNCE flag in the 378 * RTM_GET command is an indication to the kernel 379 * routing code that the interface associated with 380 * the prefix route covering the local end of the 381 * PPP link should be returned, on which ARP applies. 382 */ 383 rtm = rtmsg(RTM_GET, dst, &sdl_m); 384 if (rtm == NULL) { 385 warn("%s", host); 386 return (1); 387 } 388 addr = (struct sockaddr_inarp *)(rtm + 1); 389 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 390 391 if ((sdl->sdl_family != AF_LINK) || 392 (rtm->rtm_flags & RTF_GATEWAY) || 393 !valid_type(sdl->sdl_type)) { 394 printf("cannot intuit interface index and type for %s\n", host); 395 return (1); 396 } 397 sdl_m.sdl_type = sdl->sdl_type; 398 sdl_m.sdl_index = sdl->sdl_index; 399 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL); 400 } 401 402 /* 403 * Display an individual arp entry 404 */ 405 static int 406 get(char *host) 407 { 408 struct sockaddr_inarp *addr; 409 410 addr = getaddr(host); 411 if (addr == NULL) 412 return (1); 413 if (0 == search(addr->sin_addr.s_addr, print_entry)) { 414 printf("%s (%s) -- no entry", 415 host, inet_ntoa(addr->sin_addr)); 416 if (rifname) 417 printf(" on %s", rifname); 418 printf("\n"); 419 return (1); 420 } 421 return (0); 422 } 423 424 /* 425 * Delete an arp entry 426 */ 427 static int 428 delete(char *host, int do_proxy) 429 { 430 struct sockaddr_inarp *addr, *dst; 431 struct rt_msghdr *rtm; 432 struct sockaddr_dl *sdl; 433 struct sockaddr_dl sdl_m; 434 435 dst = getaddr(host); 436 if (dst == NULL) 437 return (1); 438 439 /* 440 * Perform a regular entry delete first. 441 */ 442 flags &= ~RTF_ANNOUNCE; 443 444 /* 445 * setup the data structure to notify the kernel 446 * it is the ARP entry the RTM_GET is interested 447 * in 448 */ 449 bzero(&sdl_m, sizeof(sdl_m)); 450 sdl_m.sdl_len = sizeof(sdl_m); 451 sdl_m.sdl_family = AF_LINK; 452 453 for (;;) { /* try twice */ 454 rtm = rtmsg(RTM_GET, dst, &sdl_m); 455 if (rtm == NULL) { 456 warn("%s", host); 457 return (1); 458 } 459 addr = (struct sockaddr_inarp *)(rtm + 1); 460 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 461 462 /* 463 * With the new L2/L3 restructure, the route 464 * returned is a prefix route. The important 465 * piece of information from the previous 466 * RTM_GET is the interface index. In the 467 * case of ECMP, the kernel will traverse 468 * the route group for the given entry. 469 */ 470 if (sdl->sdl_family == AF_LINK && 471 !(rtm->rtm_flags & RTF_GATEWAY) && 472 valid_type(sdl->sdl_type) ) { 473 addr->sin_addr.s_addr = dst->sin_addr.s_addr; 474 break; 475 } 476 477 /* 478 * Regualar entry delete failed, now check if there 479 * is a proxy-arp entry to remove. 480 */ 481 if (flags & RTF_ANNOUNCE) { 482 fprintf(stderr, "delete: cannot locate %s\n",host); 483 return (1); 484 } 485 486 flags |= RTF_ANNOUNCE; 487 } 488 rtm->rtm_flags |= RTF_LLDATA; 489 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 490 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 491 return (0); 492 } 493 return (1); 494 } 495 496 497 /* 498 * Search the arp table and do some action on matching entries 499 */ 500 static int 501 search(u_long addr, action_fn *action) 502 { 503 int mib[6]; 504 size_t needed; 505 char *lim, *buf, *next; 506 struct rt_msghdr *rtm; 507 struct sockaddr_inarp *sin2; 508 struct sockaddr_dl *sdl; 509 char ifname[IF_NAMESIZE]; 510 int st, found_entry = 0; 511 512 mib[0] = CTL_NET; 513 mib[1] = PF_ROUTE; 514 mib[2] = 0; 515 mib[3] = AF_INET; 516 mib[4] = NET_RT_FLAGS; 517 #ifdef RTF_LLINFO 518 mib[5] = RTF_LLINFO; 519 #else 520 mib[5] = 0; 521 #endif 522 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 523 err(1, "route-sysctl-estimate"); 524 if (needed == 0) /* empty table */ 525 return 0; 526 buf = NULL; 527 for (;;) { 528 buf = reallocf(buf, needed); 529 if (buf == NULL) 530 errx(1, "could not reallocate memory"); 531 st = sysctl(mib, 6, buf, &needed, NULL, 0); 532 if (st == 0 || errno != ENOMEM) 533 break; 534 needed += needed / 8; 535 } 536 if (st == -1) 537 err(1, "actual retrieval of routing table"); 538 lim = buf + needed; 539 for (next = buf; next < lim; next += rtm->rtm_msglen) { 540 rtm = (struct rt_msghdr *)next; 541 sin2 = (struct sockaddr_inarp *)(rtm + 1); 542 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 543 if (rifname && if_indextoname(sdl->sdl_index, ifname) && 544 strcmp(ifname, rifname)) 545 continue; 546 if (addr) { 547 if (addr != sin2->sin_addr.s_addr) 548 continue; 549 found_entry = 1; 550 } 551 (*action)(sdl, sin2, rtm); 552 } 553 free(buf); 554 return (found_entry); 555 } 556 557 /* 558 * Display an arp entry 559 */ 560 static char lifname[IF_NAMESIZE]; 561 static int64_t lifindex = -1; 562 563 static void 564 print_entry(struct sockaddr_dl *sdl, 565 struct sockaddr_inarp *addr, struct rt_msghdr *rtm) 566 { 567 const char *host; 568 struct hostent *hp; 569 struct iso88025_sockaddr_dl_data *trld; 570 int seg; 571 572 if (nflag == 0) 573 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 574 sizeof addr->sin_addr, AF_INET); 575 else 576 hp = 0; 577 if (hp) 578 host = hp->h_name; 579 else { 580 host = "?"; 581 if (h_errno == TRY_AGAIN) 582 nflag = 1; 583 } 584 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr)); 585 if (sdl->sdl_alen) { 586 if ((sdl->sdl_type == IFT_ETHER || 587 sdl->sdl_type == IFT_L2VLAN || 588 sdl->sdl_type == IFT_BRIDGE) && 589 sdl->sdl_alen == ETHER_ADDR_LEN) 590 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl))); 591 else { 592 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 593 594 printf("%s", link_ntoa(sdl) + n); 595 } 596 } else 597 printf("(incomplete)"); 598 if (sdl->sdl_index != lifindex && 599 if_indextoname(sdl->sdl_index, lifname) != NULL) { 600 lifindex = sdl->sdl_index; 601 printf(" on %s", lifname); 602 } else if (sdl->sdl_index == lifindex) 603 printf(" on %s", lifname); 604 if (rtm->rtm_rmx.rmx_expire == 0) 605 printf(" permanent"); 606 else { 607 static struct timespec tp; 608 if (tp.tv_sec == 0) 609 clock_gettime(CLOCK_MONOTONIC, &tp); 610 if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0) 611 printf(" expires in %d seconds", (int)expire_time); 612 else 613 printf(" expired"); 614 } 615 if (addr->sin_other & SIN_PROXY) 616 printf(" published (proxy only)"); 617 if (rtm->rtm_flags & RTF_ANNOUNCE) 618 printf(" published"); 619 switch(sdl->sdl_type) { 620 case IFT_ETHER: 621 printf(" [ethernet]"); 622 break; 623 case IFT_ISO88025: 624 printf(" [token-ring]"); 625 trld = SDL_ISO88025(sdl); 626 if (trld->trld_rcf != 0) { 627 printf(" rt=%x", ntohs(trld->trld_rcf)); 628 for (seg = 0; 629 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2); 630 seg++) 631 printf(":%x", ntohs(*(trld->trld_route[seg]))); 632 } 633 break; 634 case IFT_FDDI: 635 printf(" [fddi]"); 636 break; 637 case IFT_ATM: 638 printf(" [atm]"); 639 break; 640 case IFT_L2VLAN: 641 printf(" [vlan]"); 642 break; 643 case IFT_IEEE1394: 644 printf(" [firewire]"); 645 break; 646 case IFT_BRIDGE: 647 printf(" [bridge]"); 648 break; 649 default: 650 break; 651 } 652 653 printf("\n"); 654 655 } 656 657 /* 658 * Nuke an arp entry 659 */ 660 static void 661 nuke_entry(struct sockaddr_dl *sdl __unused, 662 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused) 663 { 664 char ip[20]; 665 666 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); 667 (void)delete(ip, 0); 668 } 669 670 static void 671 usage(void) 672 { 673 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 674 "usage: arp [-n] [-i interface] hostname", 675 " arp [-n] [-i interface] -a", 676 " arp -d hostname [pub]", 677 " arp -d [-i interface] -a", 678 " arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 679 " arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 680 " arp -f filename"); 681 exit(1); 682 } 683 684 static struct rt_msghdr * 685 rtmsg(int cmd, struct sockaddr_inarp *dst, struct sockaddr_dl *sdl) 686 { 687 static int seq; 688 int rlen; 689 int l; 690 struct sockaddr_in so_mask, *som = &so_mask; 691 static int s = -1; 692 static pid_t pid; 693 694 static struct { 695 struct rt_msghdr m_rtm; 696 char m_space[512]; 697 } m_rtmsg; 698 699 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 700 char *cp = m_rtmsg.m_space; 701 702 if (s < 0) { /* first time: open socket, get pid */ 703 s = socket(PF_ROUTE, SOCK_RAW, 0); 704 if (s < 0) 705 err(1, "socket"); 706 pid = getpid(); 707 } 708 bzero(&so_mask, sizeof(so_mask)); 709 so_mask.sin_len = 8; 710 so_mask.sin_addr.s_addr = 0xffffffff; 711 712 errno = 0; 713 /* 714 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer 715 * appropriately. 716 */ 717 if (cmd == RTM_DELETE) 718 goto doit; 719 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 720 rtm->rtm_flags = flags; 721 rtm->rtm_version = RTM_VERSION; 722 723 switch (cmd) { 724 default: 725 errx(1, "internal wrong cmd"); 726 case RTM_ADD: 727 rtm->rtm_addrs |= RTA_GATEWAY; 728 rtm->rtm_rmx.rmx_expire = expire_time; 729 rtm->rtm_inits = RTV_EXPIRE; 730 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 731 dst->sin_other = 0; 732 if (doing_proxy) { 733 if (proxy_only) 734 dst->sin_other = SIN_PROXY; 735 else { 736 rtm->rtm_addrs |= RTA_NETMASK; 737 rtm->rtm_flags &= ~RTF_HOST; 738 } 739 } 740 /* FALLTHROUGH */ 741 case RTM_GET: 742 rtm->rtm_addrs |= RTA_DST; 743 } 744 #define NEXTADDR(w, s) \ 745 do { \ 746 if ((s) != NULL && rtm->rtm_addrs & (w)) { \ 747 bcopy((s), cp, sizeof(*(s))); \ 748 cp += SA_SIZE(s); \ 749 } \ 750 } while (0) 751 752 NEXTADDR(RTA_DST, dst); 753 NEXTADDR(RTA_GATEWAY, sdl); 754 NEXTADDR(RTA_NETMASK, som); 755 756 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 757 doit: 758 l = rtm->rtm_msglen; 759 rtm->rtm_seq = ++seq; 760 rtm->rtm_type = cmd; 761 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 762 if (errno != ESRCH || cmd != RTM_DELETE) { 763 warn("writing to routing socket"); 764 return (NULL); 765 } 766 } 767 do { 768 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 769 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 770 if (l < 0) 771 warn("read from routing socket"); 772 return (rtm); 773 } 774 775 /* 776 * get_ether_addr - get the hardware address of an interface on the 777 * the same subnet as ipaddr. 778 */ 779 #define MAX_IFS 32 780 781 static int 782 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr) 783 { 784 struct ifreq *ifr, *ifend, *ifp; 785 in_addr_t ina, mask; 786 struct sockaddr_dl *dla; 787 struct ifreq ifreq; 788 struct ifconf ifc; 789 struct ifreq ifs[MAX_IFS]; 790 int sock; 791 int retval = 0; 792 793 sock = socket(AF_INET, SOCK_DGRAM, 0); 794 if (sock < 0) 795 err(1, "socket"); 796 797 ifc.ifc_len = sizeof(ifs); 798 ifc.ifc_req = ifs; 799 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) { 800 warnx("ioctl(SIOCGIFCONF)"); 801 goto done; 802 } 803 804 #define NEXTIFR(i) \ 805 ((struct ifreq *)((char *)&(i)->ifr_addr \ 806 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) ) 807 808 /* 809 * Scan through looking for an interface with an Internet 810 * address on the same subnet as `ipaddr'. 811 */ 812 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len); 813 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) { 814 if (ifr->ifr_addr.sa_family != AF_INET) 815 continue; 816 strncpy(ifreq.ifr_name, ifr->ifr_name, 817 sizeof(ifreq.ifr_name)); 818 ifreq.ifr_addr = ifr->ifr_addr; 819 /* 820 * Check that the interface is up, 821 * and not point-to-point or loopback. 822 */ 823 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0) 824 continue; 825 if ((ifreq.ifr_flags & 826 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 827 IFF_LOOPBACK|IFF_NOARP)) 828 != (IFF_UP|IFF_BROADCAST)) 829 continue; 830 /* 831 * Get its netmask and check that it's on 832 * the right subnet. 833 */ 834 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0) 835 continue; 836 mask = ((struct sockaddr_in *) 837 &ifreq.ifr_addr)->sin_addr.s_addr; 838 ina = ((struct sockaddr_in *) 839 &ifr->ifr_addr)->sin_addr.s_addr; 840 if ((ipaddr & mask) == (ina & mask)) 841 break; /* ok, we got it! */ 842 } 843 844 if (ifr >= ifend) 845 goto done; 846 847 /* 848 * Now scan through again looking for a link-level address 849 * for this interface. 850 */ 851 ifp = ifr; 852 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr)) 853 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && 854 ifr->ifr_addr.sa_family == AF_LINK) 855 break; 856 if (ifr >= ifend) 857 goto done; 858 /* 859 * Found the link-level address - copy it out 860 */ 861 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 862 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 863 printf("using interface %s for proxy with address ", 864 ifp->ifr_name); 865 printf("%s\n", ether_ntoa(hwaddr)); 866 retval = dla->sdl_alen; 867 done: 868 close(sock); 869 return (retval); 870 } 871