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 37static 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 43static 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 84typedef void (action_fn)(struct sockaddr_dl *sdl, struct sockaddr_in *s_in, 85 struct rt_msghdr *rtm); 86 87static int search(u_long addr, action_fn *action); 88static action_fn print_entry; 89static action_fn nuke_entry; 90 91static int delete(char *host); 92static void usage(void); 93static int set(int argc, char **argv); 94static int get(char *host); 95static int file(char *name); 96static struct rt_msghdr *rtmsg(int cmd, 97 struct sockaddr_in *dst, struct sockaddr_dl *sdl); 98static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 99static struct sockaddr_in *getaddr(char *host); 100static int valid_type(int type); 101 102static int nflag; /* no reverse dns lookups */ 103static char *rifname; 104 105static time_t expire_time; 106static int flags, doing_proxy; 107 108struct 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 121int 122main(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 */ 231static int 232file(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 */ 271static struct sockaddr_in * 272getaddr(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 */ 295static int 296valid_type(int type) 297{ 298 299 switch (type) { 300 case IFT_ETHER: 301 case IFT_FDDI: 302 case IFT_IEEE1394: 303 case IFT_INFINIBAND: 304 case IFT_ISO88023: 305 case IFT_ISO88024: 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, NULL); 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; 470 471 dst = getaddr(host); 472 if (dst == NULL) 473 return (1); 474 475 /* 476 * Perform a regular entry delete first. 477 */ 478 flags &= ~RTF_ANNOUNCE; 479 480 for (;;) { /* try twice */ 481 rtm = rtmsg(RTM_GET, dst, NULL); 482 if (rtm == NULL) { 483 xo_warn("%s", host); 484 return (1); 485 } 486 addr = (struct sockaddr_in *)(rtm + 1); 487 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 488 489 /* 490 * With the new L2/L3 restructure, the route 491 * returned is a prefix route. The important 492 * piece of information from the previous 493 * RTM_GET is the interface index. In the 494 * case of ECMP, the kernel will traverse 495 * the route group for the given entry. 496 */ 497 if (sdl->sdl_family == AF_LINK && 498 !(rtm->rtm_flags & RTF_GATEWAY) && 499 valid_type(sdl->sdl_type) ) { 500 addr->sin_addr.s_addr = dst->sin_addr.s_addr; 501 break; 502 } 503 504 /* 505 * Regular entry delete failed, now check if there 506 * is a proxy-arp entry to remove. 507 */ 508 if (flags & RTF_ANNOUNCE) { 509 xo_warnx("delete: cannot locate %s", host); 510 return (1); 511 } 512 513 flags |= RTF_ANNOUNCE; 514 } 515 rtm->rtm_flags |= RTF_LLDATA; 516 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 517 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 518 return (0); 519 } 520 return (1); 521} 522 523 524/* 525 * Search the arp table and do some action on matching entries 526 */ 527static int 528search(u_long addr, action_fn *action) 529{ 530 int mib[6]; 531 size_t needed; 532 char *lim, *buf, *next; 533 struct rt_msghdr *rtm; 534 struct sockaddr_in *sin2; 535 struct sockaddr_dl *sdl; 536 char ifname[IF_NAMESIZE]; 537 int st, found_entry = 0; 538 539 mib[0] = CTL_NET; 540 mib[1] = PF_ROUTE; 541 mib[2] = 0; 542 mib[3] = AF_INET; 543 mib[4] = NET_RT_FLAGS; 544#ifdef RTF_LLINFO 545 mib[5] = RTF_LLINFO; 546#else 547 mib[5] = 0; 548#endif 549 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 550 xo_err(1, "route-sysctl-estimate"); 551 if (needed == 0) /* empty table */ 552 return 0; 553 buf = NULL; 554 for (;;) { 555 buf = reallocf(buf, needed); 556 if (buf == NULL) 557 xo_errx(1, "could not reallocate memory"); 558 st = sysctl(mib, 6, buf, &needed, NULL, 0); 559 if (st == 0 || errno != ENOMEM) 560 break; 561 needed += needed / 8; 562 } 563 if (st == -1) 564 xo_err(1, "actual retrieval of routing table"); 565 lim = buf + needed; 566 for (next = buf; next < lim; next += rtm->rtm_msglen) { 567 rtm = (struct rt_msghdr *)next; 568 sin2 = (struct sockaddr_in *)(rtm + 1); 569 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 570 if (rifname && if_indextoname(sdl->sdl_index, ifname) && 571 strcmp(ifname, rifname)) 572 continue; 573 if (addr) { 574 if (addr != sin2->sin_addr.s_addr) 575 continue; 576 found_entry = 1; 577 } 578 (*action)(sdl, sin2, rtm); 579 } 580 free(buf); 581 return (found_entry); 582} 583 584/* 585 * Display an arp entry 586 */ 587 588static void 589print_entry(struct sockaddr_dl *sdl, 590 struct sockaddr_in *addr, struct rt_msghdr *rtm) 591{ 592 const char *host; 593 struct hostent *hp; 594 struct if_nameindex *p; 595 596 if (ifnameindex == NULL) 597 if ((ifnameindex = if_nameindex()) == NULL) 598 xo_err(1, "cannot retrieve interface names"); 599 600 xo_open_instance("arp-cache"); 601 602 if (nflag == 0) 603 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 604 sizeof addr->sin_addr, AF_INET); 605 else 606 hp = 0; 607 if (hp) 608 host = hp->h_name; 609 else { 610 host = "?"; 611 if (h_errno == TRY_AGAIN) 612 nflag = 1; 613 } 614 xo_emit("{:hostname/%s} ({:ip-address/%s}) at ", host, 615 inet_ntoa(addr->sin_addr)); 616 if (sdl->sdl_alen) { 617 if ((sdl->sdl_type == IFT_ETHER || 618 sdl->sdl_type == IFT_L2VLAN || 619 sdl->sdl_type == IFT_BRIDGE) && 620 sdl->sdl_alen == ETHER_ADDR_LEN) 621 xo_emit("{:mac-address/%s}", 622 ether_ntoa((struct ether_addr *)LLADDR(sdl))); 623 else { 624 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 625 626 xo_emit("{:mac-address/%s}", link_ntoa(sdl) + n); 627 } 628 } else 629 xo_emit("{d:/(incomplete)}{en:incomplete/true}"); 630 631 for (p = ifnameindex; p && p->if_index && p->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 */ 688static void 689nuke_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 701static void 702usage(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 715static struct rt_msghdr * 716rtmsg(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; 783doit: 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 808static int 809get_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; 889done: 890 close(sock); 891 return (retval); 892} 893