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 35static 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 41static 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: stable/11/usr.sbin/arp/arp.c 369818 2021-05-17 10:01:31Z avatar $"); 46 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#include <net/iso88025.h> 64 65#include <netinet/in.h> 66#include <netinet/if_ether.h> 67 68#include <arpa/inet.h> 69 70#include <ctype.h> 71#include <err.h> 72#include <errno.h> 73#include <netdb.h> 74#include <nlist.h> 75#include <paths.h> 76#include <stdio.h> 77#include <stdlib.h> 78#include <string.h> 79#include <strings.h> 80#include <unistd.h> 81#include <libxo/xo.h> 82 83typedef void (action_fn)(struct sockaddr_dl *sdl, struct sockaddr_in *s_in, 84 struct rt_msghdr *rtm); 85 86static int search(u_long addr, action_fn *action); 87static action_fn print_entry; 88static action_fn nuke_entry; 89 90static int delete(char *host); 91static void usage(void); 92static int set(int argc, char **argv); 93static int get(char *host); 94static int file(char *name); 95static struct rt_msghdr *rtmsg(int cmd, 96 struct sockaddr_in *dst, struct sockaddr_dl *sdl); 97static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 98static struct sockaddr_in *getaddr(char *host); 99static int valid_type(int type); 100 101static int nflag; /* no reverse dns lookups */ 102static char *rifname; 103 104static time_t expire_time; 105static int flags, doing_proxy; 106 107struct if_nameindex *ifnameindex; 108 109/* which function we're supposed to do */ 110#define F_GET 1 111#define F_SET 2 112#define F_FILESET 3 113#define F_REPLACE 4 114#define F_DELETE 5 115 116#define SETFUNC(f) { if (func) usage(); func = (f); } 117 118#define ARP_XO_VERSION "1" 119 120int 121main(int argc, char *argv[]) 122{ 123 int ch, func = 0; 124 int rtn = 0; 125 int aflag = 0; /* do it for all entries */ 126 127 argc = xo_parse_args(argc, argv); 128 if (argc < 0) 129 exit(1); 130 131 while ((ch = getopt(argc, argv, "andfsSi:")) != -1) 132 switch(ch) { 133 case 'a': 134 aflag = 1; 135 break; 136 case 'd': 137 SETFUNC(F_DELETE); 138 break; 139 case 'n': 140 nflag = 1; 141 break; 142 case 'S': 143 SETFUNC(F_REPLACE); 144 break; 145 case 's': 146 SETFUNC(F_SET); 147 break; 148 case 'f' : 149 SETFUNC(F_FILESET); 150 break; 151 case 'i': 152 rifname = optarg; 153 break; 154 case '?': 155 default: 156 usage(); 157 } 158 argc -= optind; 159 argv += optind; 160 161 if (!func) 162 func = F_GET; 163 if (rifname) { 164 if (func != F_GET && !(func == F_DELETE && aflag)) 165 xo_errx(1, "-i not applicable to this operation"); 166 if (if_nametoindex(rifname) == 0) { 167 if (errno == ENXIO) 168 xo_errx(1, "interface %s does not exist", 169 rifname); 170 else 171 xo_err(1, "if_nametoindex(%s)", rifname); 172 } 173 } 174 switch (func) { 175 case F_GET: 176 if (aflag) { 177 if (argc != 0) 178 usage(); 179 180 xo_set_version(ARP_XO_VERSION); 181 xo_open_container("arp"); 182 xo_open_list("arp-cache"); 183 184 search(0, print_entry); 185 186 xo_close_list("arp-cache"); 187 xo_close_container("arp"); 188 xo_finish(); 189 } else { 190 if (argc != 1) 191 usage(); 192 rtn = get(argv[0]); 193 } 194 break; 195 case F_SET: 196 case F_REPLACE: 197 if (argc < 2 || argc > 6) 198 usage(); 199 if (func == F_REPLACE) 200 (void)delete(argv[0]); 201 rtn = set(argc, argv) ? 1 : 0; 202 break; 203 case F_DELETE: 204 if (aflag) { 205 if (argc != 0) 206 usage(); 207 search(0, nuke_entry); 208 } else { 209 if (argc != 1) 210 usage(); 211 rtn = delete(argv[0]); 212 } 213 break; 214 case F_FILESET: 215 if (argc != 1) 216 usage(); 217 rtn = file(argv[0]); 218 break; 219 } 220 221 if (ifnameindex != NULL) 222 if_freenameindex(ifnameindex); 223 224 return (rtn); 225} 226 227/* 228 * Process a file to set standard arp entries 229 */ 230static int 231file(char *name) 232{ 233 FILE *fp; 234 int i, retval; 235 char line[100], arg[5][50], *args[5], *p; 236 237 if ((fp = fopen(name, "r")) == NULL) 238 xo_err(1, "cannot open %s", name); 239 args[0] = &arg[0][0]; 240 args[1] = &arg[1][0]; 241 args[2] = &arg[2][0]; 242 args[3] = &arg[3][0]; 243 args[4] = &arg[4][0]; 244 retval = 0; 245 while(fgets(line, sizeof(line), fp) != NULL) { 246 if ((p = strchr(line, '#')) != NULL) 247 *p = '\0'; 248 for (p = line; isblank(*p); p++); 249 if (*p == '\n' || *p == '\0') 250 continue; 251 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1], 252 arg[2], arg[3], arg[4]); 253 if (i < 2) { 254 xo_warnx("bad line: %s", line); 255 retval = 1; 256 continue; 257 } 258 if (set(i, args)) 259 retval = 1; 260 } 261 fclose(fp); 262 return (retval); 263} 264 265/* 266 * Given a hostname, fills up a (static) struct sockaddr_in with 267 * the address of the host and returns a pointer to the 268 * structure. 269 */ 270static struct sockaddr_in * 271getaddr(char *host) 272{ 273 struct hostent *hp; 274 static struct sockaddr_in reply; 275 276 bzero(&reply, sizeof(reply)); 277 reply.sin_len = sizeof(reply); 278 reply.sin_family = AF_INET; 279 reply.sin_addr.s_addr = inet_addr(host); 280 if (reply.sin_addr.s_addr == INADDR_NONE) { 281 if (!(hp = gethostbyname(host))) { 282 xo_warnx("%s: %s", host, hstrerror(h_errno)); 283 return (NULL); 284 } 285 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr, 286 sizeof reply.sin_addr); 287 } 288 return (&reply); 289} 290 291/* 292 * Returns true if the type is a valid one for ARP. 293 */ 294static int 295valid_type(int type) 296{ 297 298 switch (type) { 299 case IFT_ETHER: 300 case IFT_FDDI: 301 case IFT_IEEE1394: 302 case IFT_INFINIBAND: 303 case IFT_ISO88023: 304 case IFT_ISO88024: 305 case IFT_ISO88025: 306 case IFT_L2VLAN: 307 case IFT_BRIDGE: 308 return (1); 309 default: 310 return (0); 311 } 312} 313 314/* 315 * Set an individual arp entry 316 */ 317static int 318set(int argc, char **argv) 319{ 320 struct sockaddr_in *addr; 321 struct sockaddr_in *dst; /* what are we looking for */ 322 struct sockaddr_dl *sdl; 323 struct rt_msghdr *rtm; 324 struct ether_addr *ea; 325 char *host = argv[0], *eaddr = argv[1]; 326 struct sockaddr_dl sdl_m; 327 328 argc -= 2; 329 argv += 2; 330 331 bzero(&sdl_m, sizeof(sdl_m)); 332 sdl_m.sdl_len = sizeof(sdl_m); 333 sdl_m.sdl_family = AF_LINK; 334 335 dst = getaddr(host); 336 if (dst == NULL) 337 return (1); 338 doing_proxy = flags = expire_time = 0; 339 while (argc-- > 0) { 340 if (strcmp(argv[0], "temp") == 0) { 341 struct timespec tp; 342 int max_age; 343 size_t len = sizeof(max_age); 344 345 clock_gettime(CLOCK_MONOTONIC, &tp); 346 if (sysctlbyname("net.link.ether.inet.max_age", 347 &max_age, &len, NULL, 0) != 0) 348 xo_err(1, "sysctlbyname"); 349 expire_time = tp.tv_sec + max_age; 350 } else if (strcmp(argv[0], "pub") == 0) { 351 flags |= RTF_ANNOUNCE; 352 doing_proxy = 1; 353 if (argc && strcmp(argv[1], "only") == 0) { 354 /* 355 * Compatibility: in pre FreeBSD 8 times 356 * the "only" keyword used to mean that 357 * an ARP entry should be announced, but 358 * not installed into routing table. 359 */ 360 argc--; argv++; 361 } 362 } else if (strcmp(argv[0], "blackhole") == 0) { 363 if (flags & RTF_REJECT) { 364 xo_errx(1, "Choose one of blackhole or reject, " 365 "not both."); 366 } 367 flags |= RTF_BLACKHOLE; 368 } else if (strcmp(argv[0], "reject") == 0) { 369 if (flags & RTF_BLACKHOLE) { 370 xo_errx(1, "Choose one of blackhole or reject, " 371 "not both."); 372 } 373 flags |= RTF_REJECT; 374 } else { 375 xo_warnx("Invalid parameter '%s'", argv[0]); 376 usage(); 377 } 378 argv++; 379 } 380 ea = (struct ether_addr *)LLADDR(&sdl_m); 381 if (doing_proxy && !strcmp(eaddr, "auto")) { 382 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) { 383 xo_warnx("no interface found for %s", 384 inet_ntoa(dst->sin_addr)); 385 return (1); 386 } 387 sdl_m.sdl_alen = ETHER_ADDR_LEN; 388 } else { 389 struct ether_addr *ea1 = ether_aton(eaddr); 390 391 if (ea1 == NULL) { 392 xo_warnx("invalid Ethernet address '%s'", eaddr); 393 return (1); 394 } else { 395 *ea = *ea1; 396 sdl_m.sdl_alen = ETHER_ADDR_LEN; 397 } 398 } 399 400 /* 401 * In the case a proxy-arp entry is being added for 402 * a remote end point, the RTF_ANNOUNCE flag in the 403 * RTM_GET command is an indication to the kernel 404 * routing code that the interface associated with 405 * the prefix route covering the local end of the 406 * PPP link should be returned, on which ARP applies. 407 */ 408 rtm = rtmsg(RTM_GET, dst, &sdl_m); 409 if (rtm == NULL) { 410 xo_warn("%s", host); 411 return (1); 412 } 413 addr = (struct sockaddr_in *)(rtm + 1); 414 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 415 416 if ((sdl->sdl_family != AF_LINK) || 417 (rtm->rtm_flags & RTF_GATEWAY) || 418 !valid_type(sdl->sdl_type)) { 419 xo_warnx("cannot intuit interface index and type for %s", host); 420 return (1); 421 } 422 sdl_m.sdl_type = sdl->sdl_type; 423 sdl_m.sdl_index = sdl->sdl_index; 424 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL); 425} 426 427/* 428 * Display an individual arp entry 429 */ 430static int 431get(char *host) 432{ 433 struct sockaddr_in *addr; 434 int found; 435 436 addr = getaddr(host); 437 if (addr == NULL) 438 return (1); 439 440 xo_set_version(ARP_XO_VERSION); 441 xo_open_container("arp"); 442 xo_open_list("arp-cache"); 443 444 found = search(addr->sin_addr.s_addr, print_entry); 445 446 if (found == 0) { 447 xo_emit("{d:hostname/%s} ({d:ip-address/%s}) -- no entry", 448 host, inet_ntoa(addr->sin_addr)); 449 if (rifname) 450 xo_emit(" on {d:interface/%s}", rifname); 451 xo_emit("\n"); 452 } 453 454 xo_close_list("arp-cache"); 455 xo_close_container("arp"); 456 xo_finish(); 457 458 return (found == 0); 459} 460 461/* 462 * Delete an arp entry 463 */ 464static int 465delete(char *host) 466{ 467 struct sockaddr_in *addr, *dst; 468 struct rt_msghdr *rtm; 469 struct sockaddr_dl *sdl; 470 struct sockaddr_dl sdl_m; 471 472 dst = getaddr(host); 473 if (dst == NULL) 474 return (1); 475 476 /* 477 * Perform a regular entry delete first. 478 */ 479 flags &= ~RTF_ANNOUNCE; 480 481 /* 482 * setup the data structure to notify the kernel 483 * it is the ARP entry the RTM_GET is interested 484 * in 485 */ 486 bzero(&sdl_m, sizeof(sdl_m)); 487 sdl_m.sdl_len = sizeof(sdl_m); 488 sdl_m.sdl_family = AF_LINK; 489 490 for (;;) { /* try twice */ 491 rtm = rtmsg(RTM_GET, dst, &sdl_m); 492 if (rtm == NULL) { 493 xo_warn("%s", host); 494 return (1); 495 } 496 addr = (struct sockaddr_in *)(rtm + 1); 497 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 498 499 /* 500 * With the new L2/L3 restructure, the route 501 * returned is a prefix route. The important 502 * piece of information from the previous 503 * RTM_GET is the interface index. In the 504 * case of ECMP, the kernel will traverse 505 * the route group for the given entry. 506 */ 507 if (sdl->sdl_family == AF_LINK && 508 !(rtm->rtm_flags & RTF_GATEWAY) && 509 valid_type(sdl->sdl_type) ) { 510 addr->sin_addr.s_addr = dst->sin_addr.s_addr; 511 break; 512 } 513 514 /* 515 * Regualar entry delete failed, now check if there 516 * is a proxy-arp entry to remove. 517 */ 518 if (flags & RTF_ANNOUNCE) { 519 xo_warnx("delete: cannot locate %s", host); 520 return (1); 521 } 522 523 flags |= RTF_ANNOUNCE; 524 } 525 rtm->rtm_flags |= RTF_LLDATA; 526 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 527 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 528 return (0); 529 } 530 return (1); 531} 532 533 534/* 535 * Search the arp table and do some action on matching entries 536 */ 537static int 538search(u_long addr, action_fn *action) 539{ 540 int mib[6]; 541 size_t needed; 542 char *lim, *buf, *next; 543 struct rt_msghdr *rtm; 544 struct sockaddr_in *sin2; 545 struct sockaddr_dl *sdl; 546 char ifname[IF_NAMESIZE]; 547 int st, found_entry = 0; 548 549 mib[0] = CTL_NET; 550 mib[1] = PF_ROUTE; 551 mib[2] = 0; 552 mib[3] = AF_INET; 553 mib[4] = NET_RT_FLAGS; 554#ifdef RTF_LLINFO 555 mib[5] = RTF_LLINFO; 556#else 557 mib[5] = 0; 558#endif 559 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 560 xo_err(1, "route-sysctl-estimate"); 561 if (needed == 0) /* empty table */ 562 return 0; 563 buf = NULL; 564 for (;;) { 565 buf = reallocf(buf, needed); 566 if (buf == NULL) 567 xo_errx(1, "could not reallocate memory"); 568 st = sysctl(mib, 6, buf, &needed, NULL, 0); 569 if (st == 0 || errno != ENOMEM) 570 break; 571 needed += needed / 8; 572 } 573 if (st == -1) 574 xo_err(1, "actual retrieval of routing table"); 575 lim = buf + needed; 576 for (next = buf; next < lim; next += rtm->rtm_msglen) { 577 rtm = (struct rt_msghdr *)next; 578 sin2 = (struct sockaddr_in *)(rtm + 1); 579 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 580 if (rifname && if_indextoname(sdl->sdl_index, ifname) && 581 strcmp(ifname, rifname)) 582 continue; 583 if (addr) { 584 if (addr != sin2->sin_addr.s_addr) 585 continue; 586 found_entry = 1; 587 } 588 (*action)(sdl, sin2, rtm); 589 } 590 free(buf); 591 return (found_entry); 592} 593 594/* 595 * Display an arp entry 596 */ 597 598static void 599print_entry(struct sockaddr_dl *sdl, 600 struct sockaddr_in *addr, struct rt_msghdr *rtm) 601{ 602 const char *host; 603 struct hostent *hp; 604 struct iso88025_sockaddr_dl_data *trld; 605 struct if_nameindex *p; 606 int seg; 607 608 if (ifnameindex == NULL) 609 if ((ifnameindex = if_nameindex()) == NULL) 610 xo_err(1, "cannot retrieve interface names"); 611 612 xo_open_instance("arp-cache"); 613 614 if (nflag == 0) 615 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 616 sizeof addr->sin_addr, AF_INET); 617 else 618 hp = 0; 619 if (hp) 620 host = hp->h_name; 621 else { 622 host = "?"; 623 if (h_errno == TRY_AGAIN) 624 nflag = 1; 625 } 626 xo_emit("{:hostname/%s} ({:ip-address/%s}) at ", host, 627 inet_ntoa(addr->sin_addr)); 628 if (sdl->sdl_alen) { 629 if ((sdl->sdl_type == IFT_ETHER || 630 sdl->sdl_type == IFT_L2VLAN || 631 sdl->sdl_type == IFT_BRIDGE) && 632 sdl->sdl_alen == ETHER_ADDR_LEN) 633 xo_emit("{:mac-address/%s}", 634 ether_ntoa((struct ether_addr *)LLADDR(sdl))); 635 else { 636 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 637 638 xo_emit("{:mac-address/%s}", link_ntoa(sdl) + n); 639 } 640 } else 641 xo_emit("{d:/(incomplete)}{en:incomplete/true}"); 642 643 for (p = ifnameindex; p && p->if_index && p->if_name; p++) { 644 if (p->if_index == sdl->sdl_index) { 645 xo_emit(" on {:interface/%s}", p->if_name); 646 break; 647 } 648 } 649 650 if (rtm->rtm_rmx.rmx_expire == 0) 651 xo_emit("{d:/ permanent}{en:permanent/true}"); 652 else { 653 static struct timespec tp; 654 if (tp.tv_sec == 0) 655 clock_gettime(CLOCK_MONOTONIC, &tp); 656 if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0) 657 xo_emit(" expires in {:expires/%d} seconds", 658 (int)expire_time); 659 else 660 xo_emit("{d:/ expired}{en:expired/true}"); 661 } 662 663 if (rtm->rtm_flags & RTF_ANNOUNCE) 664 xo_emit("{d:/ published}{en:published/true}"); 665 666 switch(sdl->sdl_type) { 667 case IFT_ETHER: 668 xo_emit(" [{:type/ethernet}]"); 669 break; 670 case IFT_ISO88025: 671 xo_emit(" [{:type/token-ring}]"); 672 trld = SDL_ISO88025(sdl); 673 if (trld->trld_rcf != 0) { 674 xo_emit(" rt=%x", ntohs(trld->trld_rcf)); 675 for (seg = 0; 676 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2); 677 seg++) 678 xo_emit(":%x", ntohs(*(trld->trld_route[seg]))); 679 } 680 break; 681 case IFT_FDDI: 682 xo_emit(" [{:type/fddi}]"); 683 break; 684 case IFT_ATM: 685 xo_emit(" [{:type/atm}]"); 686 break; 687 case IFT_L2VLAN: 688 xo_emit(" [{:type/vlan}]"); 689 break; 690 case IFT_IEEE1394: 691 xo_emit(" [{:type/firewire}]"); 692 break; 693 case IFT_BRIDGE: 694 xo_emit(" [{:type/bridge}]"); 695 break; 696 case IFT_INFINIBAND: 697 xo_emit(" [{:type/infiniband}]"); 698 break; 699 default: 700 break; 701 } 702 703 xo_emit("\n"); 704 705 xo_close_instance("arp-cache"); 706} 707 708/* 709 * Nuke an arp entry 710 */ 711static void 712nuke_entry(struct sockaddr_dl *sdl __unused, 713 struct sockaddr_in *addr, struct rt_msghdr *rtm) 714{ 715 char ip[20]; 716 717 if (rtm->rtm_flags & RTF_PINNED) 718 return; 719 720 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); 721 delete(ip); 722} 723 724static void 725usage(void) 726{ 727 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 728 "usage: arp [-n] [-i interface] hostname", 729 " arp [-n] [-i interface] -a", 730 " arp -d hostname [pub]", 731 " arp -d [-i interface] -a", 732 " arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 733 " arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]", 734 " arp -f filename"); 735 exit(1); 736} 737 738static struct rt_msghdr * 739rtmsg(int cmd, struct sockaddr_in *dst, struct sockaddr_dl *sdl) 740{ 741 static int seq; 742 int rlen; 743 int l; 744 struct sockaddr_in so_mask, *som = &so_mask; 745 static int s = -1; 746 static pid_t pid; 747 748 static struct { 749 struct rt_msghdr m_rtm; 750 char m_space[512]; 751 } m_rtmsg; 752 753 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 754 char *cp = m_rtmsg.m_space; 755 756 if (s < 0) { /* first time: open socket, get pid */ 757 s = socket(PF_ROUTE, SOCK_RAW, 0); 758 if (s < 0) 759 xo_err(1, "socket"); 760 pid = getpid(); 761 } 762 bzero(&so_mask, sizeof(so_mask)); 763 so_mask.sin_len = 8; 764 so_mask.sin_addr.s_addr = 0xffffffff; 765 766 errno = 0; 767 /* 768 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer 769 * appropriately. 770 */ 771 if (cmd == RTM_DELETE) 772 goto doit; 773 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 774 rtm->rtm_flags = flags; 775 rtm->rtm_version = RTM_VERSION; 776 777 switch (cmd) { 778 default: 779 xo_errx(1, "internal wrong cmd"); 780 case RTM_ADD: 781 rtm->rtm_addrs |= RTA_GATEWAY; 782 rtm->rtm_rmx.rmx_expire = expire_time; 783 rtm->rtm_inits = RTV_EXPIRE; 784 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 785 if (doing_proxy) { 786 rtm->rtm_addrs |= RTA_NETMASK; 787 rtm->rtm_flags &= ~RTF_HOST; 788 } 789 /* FALLTHROUGH */ 790 case RTM_GET: 791 rtm->rtm_addrs |= RTA_DST; 792 } 793#define NEXTADDR(w, s) \ 794 do { \ 795 if ((s) != NULL && rtm->rtm_addrs & (w)) { \ 796 bcopy((s), cp, sizeof(*(s))); \ 797 cp += SA_SIZE(s); \ 798 } \ 799 } while (0) 800 801 NEXTADDR(RTA_DST, dst); 802 NEXTADDR(RTA_GATEWAY, sdl); 803 NEXTADDR(RTA_NETMASK, som); 804 805 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 806doit: 807 l = rtm->rtm_msglen; 808 rtm->rtm_seq = ++seq; 809 rtm->rtm_type = cmd; 810 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 811 if (errno != ESRCH || cmd != RTM_DELETE) { 812 xo_warn("writing to routing socket"); 813 return (NULL); 814 } 815 } 816 do { 817 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 818 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 819 if (l < 0) 820 xo_warn("read from routing socket"); 821 return (rtm); 822} 823 824/* 825 * get_ether_addr - get the hardware address of an interface on the 826 * the same subnet as ipaddr. 827 */ 828#define MAX_IFS 32 829 830static int 831get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr) 832{ 833 struct ifreq *ifr, *ifend, *ifp; 834 in_addr_t ina, mask; 835 struct sockaddr_dl *dla; 836 struct ifreq ifreq; 837 struct ifconf ifc; 838 struct ifreq ifs[MAX_IFS]; 839 int sock; 840 int retval = 0; 841 842 sock = socket(AF_INET, SOCK_DGRAM, 0); 843 if (sock < 0) 844 xo_err(1, "socket"); 845 846 ifc.ifc_len = sizeof(ifs); 847 ifc.ifc_req = ifs; 848 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) { 849 xo_warnx("ioctl(SIOCGIFCONF)"); 850 goto done; 851 } 852 853#define NEXTIFR(i) \ 854 ((struct ifreq *)((char *)&(i)->ifr_addr \ 855 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) ) 856 857 /* 858 * Scan through looking for an interface with an Internet 859 * address on the same subnet as `ipaddr'. 860 */ 861 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len); 862 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) { 863 if (ifr->ifr_addr.sa_family != AF_INET) 864 continue; 865 strncpy(ifreq.ifr_name, ifr->ifr_name, 866 sizeof(ifreq.ifr_name)); 867 ifreq.ifr_addr = ifr->ifr_addr; 868 /* 869 * Check that the interface is up, 870 * and not point-to-point or loopback. 871 */ 872 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0) 873 continue; 874 if ((ifreq.ifr_flags & 875 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 876 IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) 877 continue; 878 /* Get its netmask and check that it's on the right subnet. */ 879 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0) 880 continue; 881 mask = ((struct sockaddr_in *) 882 &ifreq.ifr_addr)->sin_addr.s_addr; 883 ina = ((struct sockaddr_in *) 884 &ifr->ifr_addr)->sin_addr.s_addr; 885 if ((ipaddr & mask) == (ina & mask)) 886 break; /* ok, we got it! */ 887 } 888 889 if (ifr >= ifend) 890 goto done; 891 892 /* 893 * Now scan through again looking for a link-level address 894 * for this interface. 895 */ 896 ifp = ifr; 897 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr)) 898 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && 899 ifr->ifr_addr.sa_family == AF_LINK) 900 break; 901 if (ifr >= ifend) 902 goto done; 903 /* 904 * Found the link-level address - copy it out 905 */ 906 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 907 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 908 printf("using interface %s for proxy with address %s\n", ifp->ifr_name, 909 ether_ntoa(hwaddr)); 910 retval = dla->sdl_alen; 911done: 912 close(sock); 913 return (retval); 914} 915