arp.c revision 76216
1126370Sphk/* 2126370Sphk * Copyright (c) 1984, 1993 3247405Salfred * The Regents of the University of California. All rights reserved. 4247405Salfred * 5247405Salfred * This code is derived from software contributed to Berkeley by 6126370Sphk * Sun Microsystems, Inc. 7126370Sphk * 8126370Sphk * Redistribution and use in source and binary forms, with or without 9126370Sphk * modification, are permitted provided that the following conditions 10126370Sphk * are met: 11126370Sphk * 1. Redistributions of source code must retain the above copyright 12126370Sphk * notice, this list of conditions and the following disclaimer. 13126370Sphk * 2. Redistributions in binary form must reproduce the above copyright 14126370Sphk * notice, this list of conditions and the following disclaimer in the 15126370Sphk * documentation and/or other materials provided with the distribution. 16126370Sphk * 3. All advertising materials mentioning features or use of this software 17126370Sphk * must display the following acknowledgement: 18126370Sphk * This product includes software developed by the University of 19126370Sphk * California, Berkeley and its contributors. 20126370Sphk * 4. Neither the name of the University nor the names of its contributors 21126370Sphk * may be used to endorse or promote products derived from this software 22126370Sphk * without specific prior written permission. 23126370Sphk * 24126370Sphk * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25126370Sphk * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26126370Sphk * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27126370Sphk * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28126370Sphk * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29126370Sphk * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30126370Sphk * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31126370Sphk * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32126370Sphk * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33126370Sphk * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34126370Sphk * SUCH DAMAGE. 35247405Salfred */ 36126370Sphk 37126370Sphk#ifndef lint 38126370Sphkstatic char const copyright[] = 39126370Sphk"@(#) Copyright (c) 1984, 1993\n\ 40126370Sphk The Regents of the University of California. All rights reserved.\n"; 41126370Sphk#endif /* not lint */ 42253719Salfred 43247405Salfred#ifndef lint 44126370Sphk#if 0 45126370Sphkstatic char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94"; 46126370Sphk#endif 47126370Sphkstatic const char rcsid[] = 48247405Salfred "$FreeBSD: head/usr.sbin/arp/arp.c 76216 2001-05-02 19:07:46Z yar $"; 49247405Salfred#endif /* not lint */ 50247405Salfred 51247405Salfred/* 52247405Salfred * arp - display, set, and delete arp table entries 53247405Salfred */ 54247405Salfred 55247405Salfred 56247405Salfred#include <sys/param.h> 57247405Salfred#include <sys/file.h> 58247405Salfred#include <sys/socket.h> 59247405Salfred#include <sys/sockio.h> 60247405Salfred#include <sys/sysctl.h> 61247405Salfred#include <sys/ioctl.h> 62130585Sphk#include <sys/time.h> 63247405Salfred 64253719Salfred#include <net/if.h> 65253719Salfred#include <net/if_dl.h> 66126370Sphk#include <net/if_types.h> 67253719Salfred#include <net/route.h> 68253719Salfred 69253719Salfred#include <netinet/in.h> 70253719Salfred#include <netinet/if_ether.h> 71253719Salfred 72253719Salfred#include <arpa/inet.h> 73247405Salfred 74247405Salfred#include <err.h> 75247405Salfred#include <errno.h> 76253719Salfred#include <netdb.h> 77253719Salfred#include <nlist.h> 78253719Salfred#include <paths.h> 79253719Salfred#include <stdio.h> 80253719Salfred#include <stdlib.h> 81253719Salfred#include <strings.h> 82253719Salfred#include <unistd.h> 83253719Salfred 84253719Salfredvoid search(u_long addr, void (*action)(struct sockaddr_dl *sdl, 85253719Salfred struct sockaddr_inarp *sin, struct rt_msghdr *rtm)); 86253719Salfredvoid print_entry(struct sockaddr_dl *sdl, 87253719Salfred struct sockaddr_inarp *sin, struct rt_msghdr *rtm); 88253719Salfredvoid nuke_entry(struct sockaddr_dl *sdl, 89253719Salfred struct sockaddr_inarp *sin, struct rt_msghdr *rtm); 90253719Salfredint delete(char *host, char *info); 91253719Salfredvoid ether_print(u_char *cp); 92253719Salfredvoid usage(void); 93253719Salfredint set(int argc, char **argv); 94253719Salfredint get(char *host); 95253719Salfredint file(char *name); 96253719Salfredvoid getsocket(void); 97253719Salfredint my_ether_aton(char *a, u_char *n); 98253719Salfredint rtmsg(int cmd); 99253719Salfredint get_ether_addr(u_int32_t ipaddr, u_char *hwaddr); 100253719Salfred 101253719Salfredstatic int pid; 102253719Salfredstatic int nflag; /* no reverse dns lookups */ 103253719Salfredstatic int aflag; /* do it for all entries */ 104253719Salfredstatic int s = -1; 105253719Salfred 106253719Salfred/* which function we're supposed to do */ 107253719Salfred#define F_GET 1 108253719Salfred#define F_SET 2 109253719Salfred#define F_FILESET 3 110253719Salfred#define F_REPLACE 4 111253719Salfred#define F_DELETE 5 112253719Salfred 113253719Salfred#define ROUNDUP(a) \ 114247405Salfred ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 115247405Salfred#define SETFUNC(f) { if (func) usage(); func = (f); } 116221121Sattilio 117221121Sattilioint 118221121Sattiliomain(argc, argv) 119221121Sattilio int argc; 120221121Sattilio char **argv; 121221121Sattilio{ 122221121Sattilio int ch, func = 0; 123247405Salfred int rtn = 0; 124247405Salfred 125247405Salfred pid = getpid(); 126247405Salfred while ((ch = getopt(argc, argv, "andfsS")) != -1) 127221121Sattilio switch((char)ch) { 128221121Sattilio case 'a': 129221121Sattilio aflag = 1; 130247405Salfred break; 131247405Salfred case 'd': 132247405Salfred SETFUNC(F_DELETE); 133247405Salfred break; 134247405Salfred case 'n': 135221121Sattilio nflag = 1; 136253719Salfred break; 137253719Salfred case 'S': 138247405Salfred SETFUNC(F_REPLACE); 139221121Sattilio break; 140221121Sattilio case 's': 141221121Sattilio SETFUNC(F_SET); 142221121Sattilio break; 143221121Sattilio case 'f' : 144221121Sattilio SETFUNC(F_FILESET); 145221121Sattilio break; 146221121Sattilio case '?': 147221121Sattilio default: 148247405Salfred usage(); 149247405Salfred } 150247405Salfred argc -= optind; 151247405Salfred argv += optind; 152247405Salfred 153253719Salfred if (!func) 154247405Salfred func = F_GET; 155247405Salfred switch (func) { 156247405Salfred case F_GET: 157247405Salfred if (aflag) { 158247405Salfred if (argc != 0) 159247405Salfred usage(); 160247405Salfred search(0, print_entry); 161247405Salfred } else { 162247405Salfred if (argc != 1) 163247405Salfred usage(); 164247405Salfred get(argv[0]); 165247405Salfred } 166247405Salfred break; 167247405Salfred case F_SET: 168247405Salfred case F_REPLACE: 169247405Salfred if (argc < 2 || argc > 5) 170247405Salfred usage(); 171247405Salfred if (func == F_REPLACE) 172247405Salfred (void) delete(argv[0], NULL); 173247405Salfred rtn = set(argc, argv) ? 1 : 0; 174221121Sattilio break; 175221121Sattilio case F_DELETE: 176221121Sattilio if (aflag) { 177221121Sattilio if (argc != 0) 178247405Salfred usage(); 179126370Sphk search(0, nuke_entry); 180247405Salfred } else { 181247405Salfred if (argc < 1 || argc > 2) 182247405Salfred usage(); 183247405Salfred rtn = delete(argv[0], argv[1]); 184247405Salfred } 185247405Salfred break; 186247405Salfred case F_FILESET: 187247405Salfred if (argc != 1) 188247405Salfred usage(); 189126370Sphk rtn = file(argv[0]); 190126370Sphk break; 191126370Sphk } 192221121Sattilio 193126370Sphk return(rtn); 194126370Sphk} 195126370Sphk 196221121Sattilio/* 197221121Sattilio * Process a file to set standard arp entries 198167950Sn_hibma */ 199165260Sn_hibmaint 200165260Sn_hibmafile(char *name) 201221121Sattilio{ 202221121Sattilio FILE *fp; 203247405Salfred int i, retval; 204126370Sphk char line[100], arg[5][50], *args[5]; 205126370Sphk 206247405Salfred if ((fp = fopen(name, "r")) == NULL) 207247405Salfred errx(1, "cannot open %s", name); 208221121Sattilio args[0] = &arg[0][0]; 209247405Salfred args[1] = &arg[1][0]; 210247405Salfred args[2] = &arg[2][0]; 211221121Sattilio args[3] = &arg[3][0]; 212247405Salfred args[4] = &arg[4][0]; 213247405Salfred retval = 0; 214247405Salfred while(fgets(line, 100, fp) != NULL) { 215247405Salfred i = sscanf(line, "%49s %49s %49s %49s %49s", arg[0], arg[1], 216247405Salfred arg[2], arg[3], arg[4]); 217247405Salfred if (i < 2) { 218247405Salfred warnx("bad line: %s", line); 219221121Sattilio retval = 1; 220221121Sattilio continue; 221247405Salfred } 222247405Salfred if (set(i, args)) 223221121Sattilio retval = 1; 224247405Salfred } 225221121Sattilio fclose(fp); 226247405Salfred return (retval); 227247405Salfred} 228247405Salfred 229247405Salfredvoid 230247405Salfredgetsocket(void) 231247405Salfred{ 232247405Salfred if (s < 0) { 233247405Salfred s = socket(PF_ROUTE, SOCK_RAW, 0); 234247405Salfred if (s < 0) 235247405Salfred err(1, "socket"); 236247405Salfred } 237247405Salfred} 238247405Salfred 239247405Salfredstruct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 240247405Salfredstruct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 241221121Sattiliostruct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 242247405Salfredint expire_time, flags, export_only, doing_proxy, found_entry; 243247405Salfredstruct { 244247405Salfred struct rt_msghdr m_rtm; 245247405Salfred char m_space[512]; 246247405Salfred} m_rtmsg; 247247405Salfred 248247405Salfred/* 249247405Salfred * Set an individual arp entry 250247405Salfred */ 251247405Salfredint 252247405Salfredset(int argc, char **argv) 253253719Salfred{ 254253719Salfred struct hostent *hp; 255247405Salfred register struct sockaddr_inarp *sin = &sin_m; 256247405Salfred register struct sockaddr_dl *sdl; 257253719Salfred register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 258247405Salfred u_char *ea; 259253719Salfred char *host = argv[0], *eaddr = argv[1]; 260247405Salfred 261247405Salfred getsocket(); 262247405Salfred argc -= 2; 263247405Salfred argv += 2; 264247405Salfred sdl_m = blank_sdl; 265247405Salfred sin_m = blank_sin; 266247405Salfred sin->sin_addr.s_addr = inet_addr(host); 267247405Salfred if (sin->sin_addr.s_addr == -1) { 268247405Salfred if (!(hp = gethostbyname(host))) { 269247405Salfred warnx("%s: %s", host, hstrerror(h_errno)); 270247405Salfred return (1); 271247405Salfred } 272247405Salfred bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 273247405Salfred sizeof sin->sin_addr); 274247405Salfred } 275247405Salfred doing_proxy = flags = export_only = expire_time = 0; 276247405Salfred while (argc-- > 0) { 277253719Salfred if (strncmp(argv[0], "temp", 4) == 0) { 278253719Salfred struct timeval time; 279253719Salfred gettimeofday(&time, 0); 280253719Salfred expire_time = time.tv_sec + 20 * 60; 281253719Salfred } 282253719Salfred else if (strncmp(argv[0], "pub", 3) == 0) { 283253719Salfred flags |= RTF_ANNOUNCE; 284253719Salfred doing_proxy = SIN_PROXY; 285253719Salfred } else if (strncmp(argv[0], "trail", 5) == 0) { 286253719Salfred printf("%s: Sending trailers is no longer supported\n", 287253719Salfred host); 288253719Salfred } 289253719Salfred argv++; 290247405Salfred } 291253719Salfred ea = (u_char *)LLADDR(&sdl_m); 292253719Salfred if (doing_proxy && !strcmp(eaddr, "auto")) { 293247405Salfred if (!get_ether_addr(sin->sin_addr.s_addr, ea)) { 294247405Salfred printf("no interface found for %s\n", 295247405Salfred inet_ntoa(sin->sin_addr)); 296221121Sattilio return (1); 297221121Sattilio } 298247405Salfred sdl_m.sdl_alen = 6; 299247405Salfred } else { 300247405Salfred if (my_ether_aton(eaddr, ea) == 0) 301247405Salfred sdl_m.sdl_alen = 6; 302247405Salfred } 303247405Salfredtryagain: 304247405Salfred if (rtmsg(RTM_GET) < 0) { 305247405Salfred warn("%s", host); 306247405Salfred return (1); 307247405Salfred } 308247405Salfred sin = (struct sockaddr_inarp *)(rtm + 1); 309247405Salfred sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 310247405Salfred if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 311247405Salfred if (sdl->sdl_family == AF_LINK && 312247405Salfred (rtm->rtm_flags & RTF_LLINFO) && 313247405Salfred !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 314247405Salfred case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 315247405Salfred case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN: 316247405Salfred goto overwrite; 317247405Salfred } 318247405Salfred if (doing_proxy == 0) { 319247405Salfred printf("set: can only proxy for %s\n", host); 320247405Salfred return (1); 321247405Salfred } 322247405Salfred if (sin_m.sin_other & SIN_PROXY) { 323247405Salfred printf("set: proxy entry exists for non 802 device\n"); 324247405Salfred return(1); 325247405Salfred } 326247405Salfred sin_m.sin_other = SIN_PROXY; 327247405Salfred export_only = 1; 328247405Salfred goto tryagain; 329247405Salfred } 330247405Salfredoverwrite: 331247405Salfred if (sdl->sdl_family != AF_LINK) { 332247405Salfred printf("cannot intuit interface index and type for %s\n", host); 333247405Salfred return (1); 334247405Salfred } 335247405Salfred sdl_m.sdl_type = sdl->sdl_type; 336247405Salfred sdl_m.sdl_index = sdl->sdl_index; 337247405Salfred return (rtmsg(RTM_ADD)); 338247405Salfred} 339247405Salfred 340247405Salfred/* 341247405Salfred * Display an individual arp entry 342247405Salfred */ 343247405Salfredint 344247405Salfredget(char *host) 345247405Salfred{ 346247405Salfred struct hostent *hp; 347247405Salfred struct sockaddr_inarp *sin = &sin_m; 348247405Salfred 349247405Salfred sin_m = blank_sin; 350247405Salfred sin->sin_addr.s_addr = inet_addr(host); 351253719Salfred if (sin->sin_addr.s_addr == -1) { 352247405Salfred if (!(hp = gethostbyname(host))) 353247405Salfred errx(1, "%s: %s", host, hstrerror(h_errno)); 354247405Salfred bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 355247405Salfred sizeof sin->sin_addr); 356247405Salfred } 357247405Salfred search(sin->sin_addr.s_addr, print_entry); 358247405Salfred if (found_entry == 0) { 359247405Salfred printf("%s (%s) -- no entry\n", 360247405Salfred host, inet_ntoa(sin->sin_addr)); 361247405Salfred return(1); 362247405Salfred } 363247405Salfred return(0); 364247405Salfred} 365247405Salfred 366247405Salfred/* 367247405Salfred * Delete an arp entry 368247405Salfred */ 369247405Salfredint 370247405Salfreddelete(char *host, char *info) 371247405Salfred{ 372247405Salfred struct hostent *hp; 373247405Salfred register struct sockaddr_inarp *sin = &sin_m; 374247405Salfred register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 375247405Salfred struct sockaddr_dl *sdl; 376247405Salfred 377247405Salfred getsocket(); 378126370Sphk sin_m = blank_sin; 379126370Sphk if (info && strncmp(info, "pro", 3) == 0) 380126370Sphk sin_m.sin_other = SIN_PROXY; 381126370Sphk sin->sin_addr.s_addr = inet_addr(host); 382126370Sphk if (sin->sin_addr.s_addr == -1) { 383126370Sphk if (!(hp = gethostbyname(host))) { 384126370Sphk warnx("%s: %s", host, hstrerror(h_errno)); 385126370Sphk return (1); 386126370Sphk } 387126370Sphk bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 388126370Sphk sizeof sin->sin_addr); 389247405Salfred } 390247405Salfredtryagain: 391126370Sphk if (rtmsg(RTM_GET) < 0) { 392126370Sphk warn("%s", host); 393126370Sphk return (1); 394126370Sphk } 395247405Salfred sin = (struct sockaddr_inarp *)(rtm + 1); 396247405Salfred sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 397247405Salfred if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 398247405Salfred if (sdl->sdl_family == AF_LINK && 399126370Sphk (rtm->rtm_flags & RTF_LLINFO) && 400126370Sphk !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 401126370Sphk case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 402126370Sphk case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN: 403126370Sphk goto delete; 404126370Sphk } 405126370Sphk } 406126370Sphk if (sin_m.sin_other & SIN_PROXY) { 407126370Sphk fprintf(stderr, "delete: can't locate %s\n",host); 408126370Sphk return (1); 409 } else { 410 sin_m.sin_other = SIN_PROXY; 411 goto tryagain; 412 } 413delete: 414 if (sdl->sdl_family != AF_LINK) { 415 printf("cannot locate %s\n", host); 416 return (1); 417 } 418 if (rtmsg(RTM_DELETE) == 0) { 419 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 420 return (0); 421 } 422 return (1); 423} 424 425/* 426 * Search the arp table and do some action on matching entries 427 */ 428void 429search(u_long addr, void (*action)(struct sockaddr_dl *sdl, 430 struct sockaddr_inarp *sin, struct rt_msghdr *rtm)) 431{ 432 int mib[6]; 433 size_t needed; 434 char *lim, *buf, *next; 435 struct rt_msghdr *rtm; 436 struct sockaddr_inarp *sin; 437 struct sockaddr_dl *sdl; 438 439 mib[0] = CTL_NET; 440 mib[1] = PF_ROUTE; 441 mib[2] = 0; 442 mib[3] = AF_INET; 443 mib[4] = NET_RT_FLAGS; 444 mib[5] = RTF_LLINFO; 445 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 446 errx(1, "route-sysctl-estimate"); 447 if ((buf = malloc(needed)) == NULL) 448 errx(1, "malloc"); 449 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 450 errx(1, "actual retrieval of routing table"); 451 lim = buf + needed; 452 for (next = buf; next < lim; next += rtm->rtm_msglen) { 453 rtm = (struct rt_msghdr *)next; 454 sin = (struct sockaddr_inarp *)(rtm + 1); 455 (char *)sdl = (char *)sin + ROUNDUP(sin->sin_len); 456 if (addr) { 457 if (addr != sin->sin_addr.s_addr) 458 continue; 459 found_entry = 1; 460 } 461 (*action)(sdl, sin, rtm); 462 } 463 free(buf); 464} 465 466/* 467 * Display an arp entry 468 */ 469void 470print_entry(struct sockaddr_dl *sdl, 471 struct sockaddr_inarp *sin, struct rt_msghdr *rtm) 472{ 473 char *host; 474 struct hostent *hp; 475 int seg; 476 477 if (nflag == 0) 478 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 479 sizeof sin->sin_addr, AF_INET); 480 else 481 hp = 0; 482 if (hp) 483 host = hp->h_name; 484 else { 485 host = "?"; 486 if (h_errno == TRY_AGAIN) 487 nflag = 1; 488 } 489 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 490 if (sdl->sdl_alen) 491 ether_print(LLADDR(sdl)); 492 else 493 printf("(incomplete)"); 494 if (rtm->rtm_rmx.rmx_expire == 0) 495 printf(" permanent"); 496 if (sin->sin_other & SIN_PROXY) 497 printf(" published (proxy only)"); 498 if (rtm->rtm_addrs & RTA_NETMASK) { 499 sin = (struct sockaddr_inarp *) 500 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 501 if (sin->sin_addr.s_addr == 0xffffffff) 502 printf(" published"); 503 if (sin->sin_len != 8) 504 printf("(weird)"); 505 } 506 switch(sdl->sdl_type) { 507 case IFT_ETHER: 508 printf(" [ethernet]"); 509 break; 510 case IFT_ISO88025: 511 printf(" [token-ring]"); 512 break; 513 case IFT_L2VLAN: 514 printf(" [vlan]"); 515 break; 516 default: 517 } 518 if (sdl->sdl_rcf != NULL) { 519 printf(" rt=%x", ntohs(sdl->sdl_rcf)); 520 for (seg = 0; seg < ((((ntohs(sdl->sdl_rcf) & 0x1f00) >> 8) - 2 ) / 2); seg++) 521 printf(":%x", ntohs(sdl->sdl_route[seg])); 522 } 523 524 printf("\n"); 525 526} 527 528/* 529 * Nuke an arp entry 530 */ 531void 532nuke_entry(struct sockaddr_dl *sdl, 533 struct sockaddr_inarp *sin, struct rt_msghdr *rtm) 534{ 535 char ip[20]; 536 537 snprintf(ip, sizeof(ip), "%s", inet_ntoa(sin->sin_addr)); 538 delete(ip, NULL); 539} 540 541void 542ether_print(u_char *cp) 543{ 544 printf("%02x:%02x:%02x:%02x:%02x:%02x", cp[0], cp[1], cp[2], cp[3], 545 cp[4], cp[5]); 546} 547 548int 549my_ether_aton(char *a, u_char *n) 550{ 551 int i, o[6]; 552 553 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 554 &o[3], &o[4], &o[5]); 555 if (i != 6) { 556 warnx("invalid Ethernet address '%s'", a); 557 return (1); 558 } 559 for (i=0; i<6; i++) 560 n[i] = o[i]; 561 return (0); 562} 563 564void 565usage(void) 566{ 567 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", 568 "usage: arp [-n] hostname", 569 " arp [-n] -a", 570 " arp -d hostname [proxy]", 571 " arp -d -a", 572 " arp -s hostname ether_addr [temp] [pub]", 573 " arp -S hostname ether_addr [temp] [pub]", 574 " arp -f filename"); 575 exit(1); 576} 577 578int 579rtmsg(int cmd) 580{ 581 static int seq; 582 int rlen; 583 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 584 register char *cp = m_rtmsg.m_space; 585 register int l; 586 587 errno = 0; 588 if (cmd == RTM_DELETE) 589 goto doit; 590 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 591 rtm->rtm_flags = flags; 592 rtm->rtm_version = RTM_VERSION; 593 594 switch (cmd) { 595 default: 596 errx(1, "internal wrong cmd"); 597 case RTM_ADD: 598 rtm->rtm_addrs |= RTA_GATEWAY; 599 rtm->rtm_rmx.rmx_expire = expire_time; 600 rtm->rtm_inits = RTV_EXPIRE; 601 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 602 sin_m.sin_other = 0; 603 if (doing_proxy) { 604 if (export_only) 605 sin_m.sin_other = SIN_PROXY; 606 else { 607 rtm->rtm_addrs |= RTA_NETMASK; 608 rtm->rtm_flags &= ~RTF_HOST; 609 } 610 } 611 /* FALLTHROUGH */ 612 case RTM_GET: 613 rtm->rtm_addrs |= RTA_DST; 614 } 615#define NEXTADDR(w, s) \ 616 if (rtm->rtm_addrs & (w)) { \ 617 bcopy((char *)&s, cp, sizeof(s)); cp += ROUNDUP(sizeof(s));} 618 619 NEXTADDR(RTA_DST, sin_m); 620 NEXTADDR(RTA_GATEWAY, sdl_m); 621 NEXTADDR(RTA_NETMASK, so_mask); 622 623 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 624doit: 625 l = rtm->rtm_msglen; 626 rtm->rtm_seq = ++seq; 627 rtm->rtm_type = cmd; 628 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 629 if (errno != ESRCH || cmd != RTM_DELETE) { 630 warn("writing to routing socket"); 631 return (-1); 632 } 633 } 634 do { 635 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 636 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 637 if (l < 0) 638 warn("read from routing socket"); 639 return (0); 640} 641 642/* 643 * get_ether_addr - get the hardware address of an interface on the 644 * the same subnet as ipaddr. 645 */ 646#define MAX_IFS 32 647 648int 649get_ether_addr(u_int32_t ipaddr, u_char *hwaddr) 650{ 651 struct ifreq *ifr, *ifend, *ifp; 652 u_int32_t ina, mask; 653 struct sockaddr_dl *dla; 654 struct ifreq ifreq; 655 struct ifconf ifc; 656 struct ifreq ifs[MAX_IFS]; 657 int s; 658 659 s = socket(AF_INET, SOCK_DGRAM, 0); 660 if (s < 0) 661 err(1, "socket"); 662 663 ifc.ifc_len = sizeof(ifs); 664 ifc.ifc_req = ifs; 665 if (ioctl(s, SIOCGIFCONF, &ifc) < 0) { 666 warnx("ioctl(SIOCGIFCONF)"); 667 close(s); 668 return 0; 669 } 670 671 /* 672 * Scan through looking for an interface with an Internet 673 * address on the same subnet as `ipaddr'. 674 */ 675 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len); 676 for (ifr = ifc.ifc_req; ifr < ifend; ) { 677 if (ifr->ifr_addr.sa_family == AF_INET) { 678 ina = ((struct sockaddr_in *) 679 &ifr->ifr_addr)->sin_addr.s_addr; 680 strncpy(ifreq.ifr_name, ifr->ifr_name, 681 sizeof(ifreq.ifr_name)); 682 /* 683 * Check that the interface is up, 684 * and not point-to-point or loopback. 685 */ 686 if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0) 687 continue; 688 if ((ifreq.ifr_flags & 689 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| 690 IFF_LOOPBACK|IFF_NOARP)) 691 != (IFF_UP|IFF_BROADCAST)) 692 goto nextif; 693 /* 694 * Get its netmask and check that it's on 695 * the right subnet. 696 */ 697 if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0) 698 continue; 699 mask = ((struct sockaddr_in *) 700 &ifreq.ifr_addr)->sin_addr.s_addr; 701 if ((ipaddr & mask) != (ina & mask)) 702 goto nextif; 703 break; 704 } 705nextif: 706 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr 707 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr))); 708 } 709 710 if (ifr >= ifend) { 711 close(s); 712 return 0; 713 } 714 715 /* 716 * Now scan through again looking for a link-level address 717 * for this interface. 718 */ 719 ifp = ifr; 720 for (ifr = ifc.ifc_req; ifr < ifend; ) { 721 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 722 && ifr->ifr_addr.sa_family == AF_LINK) { 723 /* 724 * Found the link-level address - copy it out 725 */ 726 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 727 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); 728 close (s); 729 printf("using interface %s for proxy with address ", 730 ifp->ifr_name); 731 ether_print(hwaddr); 732 printf("\n"); 733 return dla->sdl_alen; 734 } 735 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr 736 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr))); 737 } 738 return 0; 739} 740