arp.c revision 154162
1251881Speter/* 2251881Speter * Copyright (c) 1984, 1993 3251881Speter * The Regents of the University of California. All rights reserved. 4251881Speter * 5251881Speter * This code is derived from software contributed to Berkeley by 6251881Speter * Sun Microsystems, Inc. 7251881Speter * 8251881Speter * Redistribution and use in source and binary forms, with or without 9251881Speter * modification, are permitted provided that the following conditions 10251881Speter * are met: 11251881Speter * 1. Redistributions of source code must retain the above copyright 12251881Speter * notice, this list of conditions and the following disclaimer. 13251881Speter * 2. Redistributions in binary form must reproduce the above copyright 14251881Speter * notice, this list of conditions and the following disclaimer in the 15251881Speter * documentation and/or other materials provided with the distribution. 16251881Speter * 4. Neither the name of the University nor the names of its contributors 17251881Speter * may be used to endorse or promote products derived from this software 18251881Speter * without specific prior written permission. 19251881Speter * 20251881Speter * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21251881Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22251881Speter * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23251881Speter * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24251881Speter * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25251881Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26251881Speter * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27251881Speter * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28251881Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29251881Speter * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30251881Speter * SUCH DAMAGE. 31251881Speter */ 32251881Speter 33251881Speter#if 0 34251881Speter#ifndef lint 35251881Speterstatic char const copyright[] = 36251881Speter"@(#) Copyright (c) 1984, 1993\n\ 37251881Speter The Regents of the University of California. All rights reserved.\n"; 38251881Speter#endif /* not lint */ 39251881Speter 40251881Speter#ifndef lint 41251881Speterstatic char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94"; 42251881Speter#endif /* not lint */ 43251881Speter#endif 44251881Speter#include <sys/cdefs.h> 45251881Speter__FBSDID("$FreeBSD: head/usr.sbin/arp/arp.c 154162 2006-01-10 05:17:16Z brooks $"); 46251881Speter 47251881Speter/* 48251881Speter * arp - display, set, and delete arp table entries 49251881Speter */ 50251881Speter 51251881Speter 52251881Speter#include <sys/param.h> 53251881Speter#include <sys/file.h> 54251881Speter#include <sys/socket.h> 55251881Speter#include <sys/sockio.h> 56251881Speter#include <sys/sysctl.h> 57251881Speter#include <sys/ioctl.h> 58251881Speter#include <sys/time.h> 59251881Speter 60251881Speter#include <net/if.h> 61251881Speter#include <net/if_dl.h> 62251881Speter#include <net/if_types.h> 63251881Speter#include <net/route.h> 64251881Speter#include <net/iso88025.h> 65251881Speter 66251881Speter#include <netinet/in.h> 67251881Speter#include <netinet/if_ether.h> 68251881Speter 69251881Speter#include <arpa/inet.h> 70251881Speter 71251881Speter#include <ctype.h> 72251881Speter#include <err.h> 73251881Speter#include <errno.h> 74251881Speter#include <netdb.h> 75251881Speter#include <nlist.h> 76251881Speter#include <paths.h> 77251881Speter#include <stdio.h> 78251881Speter#include <stdlib.h> 79251881Speter#include <string.h> 80251881Speter#include <strings.h> 81251881Speter#include <unistd.h> 82251881Speter 83251881Spetertypedef void (action_fn)(struct sockaddr_dl *sdl, 84251881Speter struct sockaddr_inarp *s_in, struct rt_msghdr *rtm); 85251881Speter 86251881Speterstatic int search(u_long addr, action_fn *action); 87251881Speterstatic action_fn print_entry; 88251881Speterstatic action_fn nuke_entry; 89251881Speter 90251881Speterstatic int delete(char *host, int do_proxy); 91251881Speterstatic void usage(void); 92251881Speterstatic int set(int argc, char **argv); 93251881Speterstatic int get(char *host); 94251881Speterstatic int file(char *name); 95251881Speterstatic struct rt_msghdr *rtmsg(int cmd, 96251881Speter struct sockaddr_inarp *dst, struct sockaddr_dl *sdl); 97251881Speterstatic int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr); 98251881Speterstatic struct sockaddr_inarp *getaddr(char *host); 99251881Speterstatic int valid_type(int type); 100251881Speter 101251881Speterstatic int nflag; /* no reverse dns lookups */ 102251881Speterstatic char *rifname; 103251881Speter 104251881Speterstatic int expire_time, flags, doing_proxy, proxy_only; 105251881Speter 106251881Speter/* which function we're supposed to do */ 107251881Speter#define F_GET 1 108251881Speter#define F_SET 2 109251881Speter#define F_FILESET 3 110251881Speter#define F_REPLACE 4 111251881Speter#define F_DELETE 5 112251881Speter 113251881Speter#define SETFUNC(f) { if (func) usage(); func = (f); } 114251881Speter 115251881Speterint 116251881Spetermain(int argc, char *argv[]) 117251881Speter{ 118251881Speter int ch, func = 0; 119251881Speter int rtn = 0; 120251881Speter int aflag = 0; /* do it for all entries */ 121251881Speter 122251881Speter while ((ch = getopt(argc, argv, "andfsSi:")) != -1) 123251881Speter switch((char)ch) { 124251881Speter case 'a': 125251881Speter aflag = 1; 126251881Speter break; 127251881Speter case 'd': 128251881Speter SETFUNC(F_DELETE); 129251881Speter break; 130251881Speter case 'n': 131251881Speter nflag = 1; 132251881Speter break; 133251881Speter case 'S': 134251881Speter SETFUNC(F_REPLACE); 135251881Speter break; 136251881Speter case 's': 137251881Speter SETFUNC(F_SET); 138251881Speter break; 139251881Speter case 'f' : 140251881Speter SETFUNC(F_FILESET); 141251881Speter break; 142251881Speter case 'i': 143251881Speter rifname = optarg; 144251881Speter break; 145251881Speter case '?': 146251881Speter default: 147251881Speter usage(); 148251881Speter } 149251881Speter argc -= optind; 150251881Speter argv += optind; 151251881Speter 152251881Speter if (!func) 153251881Speter func = F_GET; 154251881Speter if (rifname) { 155251881Speter if (func != F_GET && !(func == F_DELETE && aflag)) 156251881Speter errx(1, "-i not applicable to this operation"); 157251881Speter if (if_nametoindex(rifname) == 0) { 158251881Speter if (errno == ENXIO) 159251881Speter errx(1, "interface %s does not exist", rifname); 160251881Speter else 161251881Speter err(1, "if_nametoindex(%s)", rifname); 162251881Speter } 163251881Speter } 164251881Speter switch (func) { 165251881Speter case F_GET: 166251881Speter if (aflag) { 167251881Speter if (argc != 0) 168251881Speter usage(); 169251881Speter search(0, print_entry); 170251881Speter } else { 171251881Speter if (argc != 1) 172251881Speter usage(); 173251881Speter rtn = get(argv[0]); 174251881Speter } 175251881Speter break; 176251881Speter case F_SET: 177251881Speter case F_REPLACE: 178251881Speter if (argc < 2 || argc > 6) 179251881Speter usage(); 180251881Speter if (func == F_REPLACE) 181251881Speter (void)delete(argv[0], 0); 182251881Speter rtn = set(argc, argv) ? 1 : 0; 183251881Speter break; 184251881Speter case F_DELETE: 185251881Speter if (aflag) { 186251881Speter if (argc != 0) 187251881Speter usage(); 188251881Speter search(0, nuke_entry); 189251881Speter } else { 190251881Speter if (argc == 2 && strncmp(argv[1], "pub", 3) == 0) 191251881Speter ch = SIN_PROXY; 192251881Speter else if (argc == 1) 193251881Speter ch = 0; 194251881Speter else 195251881Speter usage(); 196251881Speter rtn = delete(argv[0], ch); 197251881Speter } 198251881Speter break; 199251881Speter case F_FILESET: 200251881Speter if (argc != 1) 201251881Speter usage(); 202251881Speter rtn = file(argv[0]); 203251881Speter break; 204251881Speter } 205251881Speter 206251881Speter return (rtn); 207251881Speter} 208251881Speter 209251881Speter/* 210251881Speter * Process a file to set standard arp entries 211251881Speter */ 212251881Speterstatic int 213251881Speterfile(char *name) 214251881Speter{ 215251881Speter FILE *fp; 216251881Speter int i, retval; 217251881Speter char line[100], arg[5][50], *args[5], *p; 218251881Speter 219251881Speter if ((fp = fopen(name, "r")) == NULL) 220251881Speter err(1, "cannot open %s", name); 221251881Speter args[0] = &arg[0][0]; 222251881Speter args[1] = &arg[1][0]; 223251881Speter args[2] = &arg[2][0]; 224251881Speter args[3] = &arg[3][0]; 225251881Speter args[4] = &arg[4][0]; 226251881Speter retval = 0; 227251881Speter while(fgets(line, 100, fp) != NULL) { 228251881Speter if ((p = strchr(line, '#')) != NULL) 229251881Speter *p = '\0'; 230251881Speter for (p = line; isblank(*p); p++); 231251881Speter if (*p == '\n' || *p == '\0') 232251881Speter continue; 233251881Speter i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1], 234251881Speter arg[2], arg[3], arg[4]); 235251881Speter if (i < 2) { 236251881Speter warnx("bad line: %s", line); 237251881Speter retval = 1; 238251881Speter continue; 239251881Speter } 240251881Speter if (set(i, args)) 241251881Speter retval = 1; 242251881Speter } 243251881Speter fclose(fp); 244251881Speter return (retval); 245251881Speter} 246251881Speter 247251881Speter/* 248251881Speter * Given a hostname, fills up a (static) struct sockaddr_inarp with 249251881Speter * the address of the host and returns a pointer to the 250251881Speter * structure. 251251881Speter */ 252251881Speterstatic struct sockaddr_inarp * 253251881Spetergetaddr(char *host) 254251881Speter{ 255251881Speter struct hostent *hp; 256251881Speter static struct sockaddr_inarp reply; 257251881Speter 258251881Speter bzero(&reply, sizeof(reply)); 259251881Speter reply.sin_len = sizeof(reply); 260251881Speter reply.sin_family = AF_INET; 261251881Speter reply.sin_addr.s_addr = inet_addr(host); 262251881Speter if (reply.sin_addr.s_addr == INADDR_NONE) { 263251881Speter if (!(hp = gethostbyname(host))) { 264251881Speter warnx("%s: %s", host, hstrerror(h_errno)); 265251881Speter return (NULL); 266251881Speter } 267251881Speter bcopy((char *)hp->h_addr, (char *)&reply.sin_addr, 268251881Speter sizeof reply.sin_addr); 269251881Speter } 270251881Speter return (&reply); 271251881Speter} 272251881Speter 273251881Speter/* 274251881Speter * Returns true if the type is a valid one for ARP. 275251881Speter */ 276251881Speterstatic int 277251881Spetervalid_type(int type) 278251881Speter{ 279251881Speter 280251881Speter switch (type) { 281251881Speter case IFT_ETHER: 282251881Speter case IFT_FDDI: 283251881Speter case IFT_ISO88023: 284251881Speter case IFT_ISO88024: 285251881Speter case IFT_ISO88025: 286251881Speter case IFT_L2VLAN: 287251881Speter case IFT_BRIDGE: 288251881Speter return (1); 289251881Speter default: 290251881Speter return (0); 291251881Speter } 292251881Speter} 293251881Speter 294251881Speter/* 295251881Speter * Set an individual arp entry 296251881Speter */ 297251881Speterstatic int 298251881Speterset(int argc, char **argv) 299251881Speter{ 300251881Speter struct sockaddr_inarp *addr; 301251881Speter struct sockaddr_inarp *dst; /* what are we looking for */ 302251881Speter struct sockaddr_dl *sdl; 303251881Speter struct rt_msghdr *rtm; 304251881Speter struct ether_addr *ea; 305251881Speter char *host = argv[0], *eaddr = argv[1]; 306251881Speter struct sockaddr_dl sdl_m; 307251881Speter 308251881Speter argc -= 2; 309251881Speter argv += 2; 310251881Speter 311251881Speter bzero(&sdl_m, sizeof(sdl_m)); 312251881Speter sdl_m.sdl_len = sizeof(sdl_m); 313251881Speter sdl_m.sdl_family = AF_LINK; 314251881Speter 315251881Speter dst = getaddr(host); 316251881Speter if (dst == NULL) 317251881Speter return (1); 318251881Speter doing_proxy = flags = proxy_only = expire_time = 0; 319251881Speter while (argc-- > 0) { 320251881Speter if (strncmp(argv[0], "temp", 4) == 0) { 321251881Speter struct timeval tv; 322251881Speter gettimeofday(&tv, 0); 323251881Speter expire_time = tv.tv_sec + 20 * 60; 324251881Speter } 325251881Speter else if (strncmp(argv[0], "pub", 3) == 0) { 326251881Speter flags |= RTF_ANNOUNCE; 327251881Speter doing_proxy = 1; 328251881Speter if (argc && strncmp(argv[1], "only", 3) == 0) { 329251881Speter proxy_only = 1; 330251881Speter dst->sin_other = SIN_PROXY; 331251881Speter argc--; argv++; 332251881Speter } 333251881Speter } else if (strncmp(argv[0], "trail", 5) == 0) { 334251881Speter /* XXX deprecated and undocumented feature */ 335251881Speter printf("%s: Sending trailers is no longer supported\n", 336251881Speter host); 337251881Speter } 338251881Speter argv++; 339251881Speter } 340251881Speter ea = (struct ether_addr *)LLADDR(&sdl_m); 341251881Speter if (doing_proxy && !strcmp(eaddr, "auto")) { 342251881Speter if (!get_ether_addr(dst->sin_addr.s_addr, ea)) { 343251881Speter printf("no interface found for %s\n", 344251881Speter inet_ntoa(dst->sin_addr)); 345251881Speter return (1); 346251881Speter } 347251881Speter sdl_m.sdl_alen = ETHER_ADDR_LEN; 348251881Speter } else { 349251881Speter struct ether_addr *ea1 = ether_aton(eaddr); 350251881Speter 351251881Speter if (ea1 == NULL) 352251881Speter warnx("invalid Ethernet address '%s'", eaddr); 353251881Speter else { 354251881Speter *ea = *ea1; 355251881Speter sdl_m.sdl_alen = ETHER_ADDR_LEN; 356251881Speter } 357251881Speter } 358251881Speter for (;;) { /* try at most twice */ 359251881Speter rtm = rtmsg(RTM_GET, dst, &sdl_m); 360251881Speter if (rtm == NULL) { 361251881Speter warn("%s", host); 362251881Speter return (1); 363251881Speter } 364251881Speter addr = (struct sockaddr_inarp *)(rtm + 1); 365251881Speter sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 366251881Speter if (addr->sin_addr.s_addr != dst->sin_addr.s_addr) 367251881Speter break; 368251881Speter if (sdl->sdl_family == AF_LINK && 369251881Speter (rtm->rtm_flags & RTF_LLINFO) && 370251881Speter !(rtm->rtm_flags & RTF_GATEWAY) && 371251881Speter valid_type(sdl->sdl_type) ) 372251881Speter break; 373251881Speter if (doing_proxy == 0) { 374251881Speter printf("set: can only proxy for %s\n", host); 375251881Speter return (1); 376251881Speter } 377251881Speter if (dst->sin_other & SIN_PROXY) { 378251881Speter printf("set: proxy entry exists for non 802 device\n"); 379251881Speter return (1); 380251881Speter } 381251881Speter dst->sin_other = SIN_PROXY; 382251881Speter proxy_only = 1; 383251881Speter } 384251881Speter 385251881Speter if (sdl->sdl_family != AF_LINK) { 386251881Speter printf("cannot intuit interface index and type for %s\n", host); 387251881Speter return (1); 388251881Speter } 389251881Speter sdl_m.sdl_type = sdl->sdl_type; 390251881Speter sdl_m.sdl_index = sdl->sdl_index; 391251881Speter return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL); 392251881Speter} 393251881Speter 394251881Speter/* 395251881Speter * Display an individual arp entry 396251881Speter */ 397251881Speterstatic int 398251881Speterget(char *host) 399251881Speter{ 400251881Speter struct sockaddr_inarp *addr; 401251881Speter 402251881Speter addr = getaddr(host); 403251881Speter if (addr == NULL) 404251881Speter return (1); 405251881Speter if (0 == search(addr->sin_addr.s_addr, print_entry)) { 406251881Speter printf("%s (%s) -- no entry", 407251881Speter host, inet_ntoa(addr->sin_addr)); 408251881Speter if (rifname) 409251881Speter printf(" on %s", rifname); 410251881Speter printf("\n"); 411251881Speter return (1); 412251881Speter } 413251881Speter return (0); 414251881Speter} 415251881Speter 416251881Speter/* 417251881Speter * Delete an arp entry 418251881Speter */ 419251881Speterstatic int 420251881Speterdelete(char *host, int do_proxy) 421251881Speter{ 422251881Speter struct sockaddr_inarp *addr, *dst; 423251881Speter struct rt_msghdr *rtm; 424251881Speter struct sockaddr_dl *sdl; 425251881Speter 426251881Speter dst = getaddr(host); 427251881Speter if (dst == NULL) 428251881Speter return (1); 429251881Speter dst->sin_other = do_proxy; 430251881Speter for (;;) { /* try twice */ 431251881Speter rtm = rtmsg(RTM_GET, dst, NULL); 432 if (rtm == NULL) { 433 warn("%s", host); 434 return (1); 435 } 436 addr = (struct sockaddr_inarp *)(rtm + 1); 437 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr); 438 if (addr->sin_addr.s_addr == dst->sin_addr.s_addr && 439 sdl->sdl_family == AF_LINK && 440 (rtm->rtm_flags & RTF_LLINFO) && 441 !(rtm->rtm_flags & RTF_GATEWAY) && 442 valid_type(sdl->sdl_type) ) 443 break; /* found it */ 444 if (dst->sin_other & SIN_PROXY) { 445 fprintf(stderr, "delete: cannot locate %s\n",host); 446 return (1); 447 } 448 dst->sin_other = SIN_PROXY; 449 } 450 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) { 451 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); 452 return (0); 453 } 454 return (1); 455} 456 457/* 458 * Search the arp table and do some action on matching entries 459 */ 460static int 461search(u_long addr, action_fn *action) 462{ 463 int mib[6]; 464 size_t needed; 465 char *lim, *buf, *newbuf, *next; 466 struct rt_msghdr *rtm; 467 struct sockaddr_inarp *sin2; 468 struct sockaddr_dl *sdl; 469 char ifname[IF_NAMESIZE]; 470 int st, found_entry = 0; 471 472 mib[0] = CTL_NET; 473 mib[1] = PF_ROUTE; 474 mib[2] = 0; 475 mib[3] = AF_INET; 476 mib[4] = NET_RT_FLAGS; 477 mib[5] = RTF_LLINFO; 478 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 479 err(1, "route-sysctl-estimate"); 480 if (needed == 0) /* empty table */ 481 return 0; 482 buf = NULL; 483 for (;;) { 484 newbuf = realloc(buf, needed); 485 if (newbuf == NULL) { 486 if (buf != NULL) 487 free(buf); 488 errx(1, "could not reallocate memory"); 489 } 490 buf = newbuf; 491 st = sysctl(mib, 6, buf, &needed, NULL, 0); 492 if (st == 0 || errno != ENOMEM) 493 break; 494 needed += needed / 8; 495 } 496 if (st == -1) 497 err(1, "actual retrieval of routing table"); 498 lim = buf + needed; 499 for (next = buf; next < lim; next += rtm->rtm_msglen) { 500 rtm = (struct rt_msghdr *)next; 501 sin2 = (struct sockaddr_inarp *)(rtm + 1); 502 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2)); 503 if (rifname && if_indextoname(sdl->sdl_index, ifname) && 504 strcmp(ifname, rifname)) 505 continue; 506 if (addr) { 507 if (addr != sin2->sin_addr.s_addr) 508 continue; 509 found_entry = 1; 510 } 511 (*action)(sdl, sin2, rtm); 512 } 513 free(buf); 514 return (found_entry); 515} 516 517/* 518 * Display an arp entry 519 */ 520static void 521print_entry(struct sockaddr_dl *sdl, 522 struct sockaddr_inarp *addr, struct rt_msghdr *rtm) 523{ 524 const char *host; 525 struct hostent *hp; 526 struct iso88025_sockaddr_dl_data *trld; 527 char ifname[IF_NAMESIZE]; 528 int seg; 529 530 if (nflag == 0) 531 hp = gethostbyaddr((caddr_t)&(addr->sin_addr), 532 sizeof addr->sin_addr, AF_INET); 533 else 534 hp = 0; 535 if (hp) 536 host = hp->h_name; 537 else { 538 host = "?"; 539 if (h_errno == TRY_AGAIN) 540 nflag = 1; 541 } 542 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr)); 543 if (sdl->sdl_alen) { 544 if ((sdl->sdl_type == IFT_ETHER || 545 sdl->sdl_type == IFT_L2VLAN || 546 sdl->sdl_type == IFT_BRIDGE) && 547 sdl->sdl_alen == ETHER_ADDR_LEN) 548 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl))); 549 else { 550 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0; 551 552 printf("%s", link_ntoa(sdl) + n); 553 } 554 } else 555 printf("(incomplete)"); 556 if (if_indextoname(sdl->sdl_index, ifname) != NULL) 557 printf(" on %s", ifname); 558 if (rtm->rtm_rmx.rmx_expire == 0) 559 printf(" permanent"); 560 if (addr->sin_other & SIN_PROXY) 561 printf(" published (proxy only)"); 562 if (rtm->rtm_addrs & RTA_NETMASK) { 563 addr = (struct sockaddr_inarp *) 564 (SA_SIZE(sdl) + (char *)sdl); 565 if (addr->sin_addr.s_addr == 0xffffffff) 566 printf(" published"); 567 if (addr->sin_len != 8) 568 printf("(weird)"); 569 } 570 switch(sdl->sdl_type) { 571 case IFT_ETHER: 572 printf(" [ethernet]"); 573 break; 574 case IFT_ISO88025: 575 printf(" [token-ring]"); 576 trld = SDL_ISO88025(sdl); 577 if (trld->trld_rcf != 0) { 578 printf(" rt=%x", ntohs(trld->trld_rcf)); 579 for (seg = 0; 580 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2); 581 seg++) 582 printf(":%x", ntohs(*(trld->trld_route[seg]))); 583 } 584 break; 585 case IFT_FDDI: 586 printf(" [fddi]"); 587 break; 588 case IFT_ATM: 589 printf(" [atm]"); 590 break; 591 case IFT_L2VLAN: 592 printf(" [vlan]"); 593 break; 594 case IFT_IEEE1394: 595 printf(" [firewire]"); 596 break; 597 case IFT_BRIDGE: 598 printf(" [bridge]"); 599 break; 600 default: 601 break; 602 } 603 604 printf("\n"); 605 606} 607 608/* 609 * Nuke an arp entry 610 */ 611static void 612nuke_entry(struct sockaddr_dl *sdl __unused, 613 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused) 614{ 615 char ip[20]; 616 617 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); 618 (void)delete(ip, 0); 619} 620 621static void 622usage(void) 623{ 624 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 625 "usage: arp [-n] [-i interface] hostname", 626 " arp [-n] [-i interface] -a", 627 " arp -d hostname [pub]", 628 " arp -d -a", 629 " arp -s hostname ether_addr [temp] [pub]", 630 " arp -S hostname ether_addr [temp] [pub]", 631 " arp -f filename"); 632 exit(1); 633} 634 635static struct rt_msghdr * 636rtmsg(int cmd, struct sockaddr_inarp *dst, struct sockaddr_dl *sdl) 637{ 638 static int seq; 639 int rlen; 640 int l; 641 struct sockaddr_in so_mask; 642 static int s = -1; 643 static pid_t pid; 644 645 static struct { 646 struct rt_msghdr m_rtm; 647 char m_space[512]; 648 } m_rtmsg; 649 650 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 651 char *cp = m_rtmsg.m_space; 652 653 if (s < 0) { /* first time: open socket, get pid */ 654 s = socket(PF_ROUTE, SOCK_RAW, 0); 655 if (s < 0) 656 err(1, "socket"); 657 pid = getpid(); 658 } 659 bzero(&so_mask, sizeof(so_mask)); 660 so_mask.sin_len = 8; 661 so_mask.sin_addr.s_addr = 0xffffffff; 662 663 errno = 0; 664 /* 665 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer 666 * appropriately. 667 */ 668 if (cmd == RTM_DELETE) 669 goto doit; 670 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 671 rtm->rtm_flags = flags; 672 rtm->rtm_version = RTM_VERSION; 673 674 switch (cmd) { 675 default: 676 errx(1, "internal wrong cmd"); 677 case RTM_ADD: 678 rtm->rtm_addrs |= RTA_GATEWAY; 679 rtm->rtm_rmx.rmx_expire = expire_time; 680 rtm->rtm_inits = RTV_EXPIRE; 681 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 682 dst->sin_other = 0; 683 if (doing_proxy) { 684 if (proxy_only) 685 dst->sin_other = SIN_PROXY; 686 else { 687 rtm->rtm_addrs |= RTA_NETMASK; 688 rtm->rtm_flags &= ~RTF_HOST; 689 } 690 } 691 /* FALLTHROUGH */ 692 case RTM_GET: 693 rtm->rtm_addrs |= RTA_DST; 694 } 695#define NEXTADDR(w, s) \ 696 if ((s) != NULL && rtm->rtm_addrs & (w)) { \ 697 bcopy((s), cp, sizeof(*(s))); cp += SA_SIZE(s);} 698 699 NEXTADDR(RTA_DST, dst); 700 NEXTADDR(RTA_GATEWAY, sdl); 701 NEXTADDR(RTA_NETMASK, &so_mask); 702 703 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 704doit: 705 l = rtm->rtm_msglen; 706 rtm->rtm_seq = ++seq; 707 rtm->rtm_type = cmd; 708 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 709 if (errno != ESRCH || cmd != RTM_DELETE) { 710 warn("writing to routing socket"); 711 return (NULL); 712 } 713 } 714 do { 715 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 716 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 717 if (l < 0) 718 warn("read from routing socket"); 719 return (rtm); 720} 721 722/* 723 * get_ether_addr - get the hardware address of an interface on the 724 * the same subnet as ipaddr. 725 */ 726#define MAX_IFS 32 727 728static int 729get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr) 730{ 731 struct ifreq *ifr, *ifend, *ifp; 732 in_addr_t ina, mask; 733 struct sockaddr_dl *dla; 734 struct ifreq ifreq; 735 struct ifconf ifc; 736 struct ifreq ifs[MAX_IFS]; 737 int sock; 738 int retval = 0; 739 740 sock = socket(AF_INET, SOCK_DGRAM, 0); 741 if (sock < 0) 742 err(1, "socket"); 743 744 ifc.ifc_len = sizeof(ifs); 745 ifc.ifc_req = ifs; 746 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) { 747 warnx("ioctl(SIOCGIFCONF)"); 748 goto done; 749 } 750 751#define NEXTIFR(i) \ 752 ((struct ifreq *)((char *)&(i)->ifr_addr \ 753 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) ) 754 755 /* 756 * Scan through looking for an interface with an Internet 757 * address on the same subnet as `ipaddr'. 758 */ 759 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len); 760 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) { 761 if (ifr->ifr_addr.sa_family != AF_INET) 762 continue; 763 /* XXX can't we use *ifr instead of ifreq ? */ 764 strncpy(ifreq.ifr_name, ifr->ifr_name, 765 sizeof(ifreq.ifr_name)); 766 /* 767 * Check that the interface is up, 768 * and not point-to-point or loopback. 769 */ 770 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0) 771 continue; 772 if ((ifreq.ifr_flags & 773 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 774 IFF_LOOPBACK|IFF_NOARP)) 775 != (IFF_UP|IFF_BROADCAST)) 776 continue; 777 /* 778 * Get its netmask and check that it's on 779 * the right subnet. 780 */ 781 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0) 782 continue; 783 mask = ((struct sockaddr_in *) 784 &ifreq.ifr_addr)->sin_addr.s_addr; 785 ina = ((struct sockaddr_in *) 786 &ifr->ifr_addr)->sin_addr.s_addr; 787 if ((ipaddr & mask) == (ina & mask)) 788 break; /* ok, we got it! */ 789 } 790 791 if (ifr >= ifend) 792 goto done; 793 794 /* 795 * Now scan through again looking for a link-level address 796 * for this interface. 797 */ 798 ifp = ifr; 799 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr)) 800 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && 801 ifr->ifr_addr.sa_family == AF_LINK) 802 break; 803 if (ifr >= ifend) 804 goto done; 805 /* 806 * Found the link-level address - copy it out 807 */ 808 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 809 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 810 printf("using interface %s for proxy with address ", 811 ifp->ifr_name); 812 printf("%s\n", ether_ntoa(hwaddr)); 813 retval = dla->sdl_alen; 814done: 815 close(sock); 816 return (retval); 817} 818