2 * Copyright (c) 1984, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Sun Microsystems, Inc.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
35 static char const copyright[] =
36 "@(#) Copyright (c) 1984, 1993\n\
37 The Regents of the University of California. All rights reserved.\n";
41 static char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94";
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
48 * arp - display, set, and delete arp table entries
52 #include <sys/param.h>
54 #include <sys/socket.h>
55 #include <sys/sockio.h>
56 #include <sys/sysctl.h>
57 #include <sys/ioctl.h>
61 #include <net/if_dl.h>
62 #include <net/if_types.h>
63 #include <net/route.h>
64 #include <net/iso88025.h>
66 #include <netinet/in.h>
67 #include <netinet/if_ether.h>
69 #include <arpa/inet.h>
83 typedef void (action_fn)(struct sockaddr_dl *sdl,
84 struct sockaddr_inarp *s_in, struct rt_msghdr *rtm);
86 static int search(u_long addr, action_fn *action);
87 static action_fn print_entry;
88 static action_fn nuke_entry;
90 static int delete(char *host, int do_proxy);
91 static void usage(void);
92 static int set(int argc, char **argv);
93 static int get(char *host);
94 static int file(char *name);
95 static struct rt_msghdr *rtmsg(int cmd,
96 struct sockaddr_inarp *dst, struct sockaddr_dl *sdl);
97 static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr);
98 static struct sockaddr_inarp *getaddr(char *host);
99 static int valid_type(int type);
101 static int nflag; /* no reverse dns lookups */
102 static char *rifname;
104 static int expire_time, flags, doing_proxy, proxy_only;
106 /* which function we're supposed to do */
113 #define SETFUNC(f) { if (func) usage(); func = (f); }
116 main(int argc, char *argv[])
120 int aflag = 0; /* do it for all entries */
122 while ((ch = getopt(argc, argv, "andfsSi:")) != -1)
155 if (func != F_GET && !(func == F_DELETE && aflag))
156 errx(1, "-i not applicable to this operation");
157 if (if_nametoindex(rifname) == 0) {
159 errx(1, "interface %s does not exist", rifname);
161 err(1, "if_nametoindex(%s)", rifname);
169 search(0, print_entry);
178 if (argc < 2 || argc > 6)
180 if (func == F_REPLACE)
181 (void)delete(argv[0], 0);
182 rtn = set(argc, argv) ? 1 : 0;
188 search(0, nuke_entry);
190 if (argc == 2 && strncmp(argv[1], "pub", 3) == 0)
196 rtn = delete(argv[0], ch);
210 * Process a file to set standard arp entries
217 char line[100], arg[5][50], *args[5], *p;
219 if ((fp = fopen(name, "r")) == NULL)
220 err(1, "cannot open %s", name);
221 args[0] = &arg[0][0];
222 args[1] = &arg[1][0];
223 args[2] = &arg[2][0];
224 args[3] = &arg[3][0];
225 args[4] = &arg[4][0];
227 while(fgets(line, sizeof(line), fp) != NULL) {
228 if ((p = strchr(line, '#')) != NULL)
230 for (p = line; isblank(*p); p++);
231 if (*p == '\n' || *p == '\0')
233 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1],
234 arg[2], arg[3], arg[4]);
236 warnx("bad line: %s", line);
248 * Given a hostname, fills up a (static) struct sockaddr_inarp with
249 * the address of the host and returns a pointer to the
252 static struct sockaddr_inarp *
256 static struct sockaddr_inarp reply;
258 bzero(&reply, sizeof(reply));
259 reply.sin_len = sizeof(reply);
260 reply.sin_family = AF_INET;
261 reply.sin_addr.s_addr = inet_addr(host);
262 if (reply.sin_addr.s_addr == INADDR_NONE) {
263 if (!(hp = gethostbyname(host))) {
264 warnx("%s: %s", host, hstrerror(h_errno));
267 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr,
268 sizeof reply.sin_addr);
274 * Returns true if the type is a valid one for ARP.
295 * Set an individual arp entry
298 set(int argc, char **argv)
300 struct sockaddr_inarp *addr;
301 struct sockaddr_inarp *dst; /* what are we looking for */
302 struct sockaddr_dl *sdl;
303 struct rt_msghdr *rtm;
304 struct ether_addr *ea;
305 char *host = argv[0], *eaddr = argv[1];
306 struct sockaddr_dl sdl_m;
311 bzero(&sdl_m, sizeof(sdl_m));
312 sdl_m.sdl_len = sizeof(sdl_m);
313 sdl_m.sdl_family = AF_LINK;
318 doing_proxy = flags = proxy_only = expire_time = 0;
320 if (strncmp(argv[0], "temp", 4) == 0) {
322 gettimeofday(&tv, 0);
323 expire_time = tv.tv_sec + 20 * 60;
324 } else if (strncmp(argv[0], "pub", 3) == 0) {
325 flags |= RTF_ANNOUNCE;
327 if (argc && strncmp(argv[1], "only", 3) == 0) {
329 dst->sin_other = SIN_PROXY;
332 } else if (strncmp(argv[0], "blackhole", 9) == 0) {
333 flags |= RTF_BLACKHOLE;
334 } else if (strncmp(argv[0], "reject", 6) == 0) {
336 } else if (strncmp(argv[0], "trail", 5) == 0) {
337 /* XXX deprecated and undocumented feature */
338 printf("%s: Sending trailers is no longer supported\n",
343 ea = (struct ether_addr *)LLADDR(&sdl_m);
344 if (doing_proxy && !strcmp(eaddr, "auto")) {
345 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) {
346 printf("no interface found for %s\n",
347 inet_ntoa(dst->sin_addr));
350 sdl_m.sdl_alen = ETHER_ADDR_LEN;
352 struct ether_addr *ea1 = ether_aton(eaddr);
355 warnx("invalid Ethernet address '%s'", eaddr);
359 sdl_m.sdl_alen = ETHER_ADDR_LEN;
362 for (;;) { /* try at most twice */
363 rtm = rtmsg(RTM_GET, dst, &sdl_m);
368 addr = (struct sockaddr_inarp *)(rtm + 1);
369 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
370 if (addr->sin_addr.s_addr != dst->sin_addr.s_addr)
372 if (sdl->sdl_family == AF_LINK &&
373 (rtm->rtm_flags & RTF_LLINFO) &&
374 !(rtm->rtm_flags & RTF_GATEWAY) &&
375 valid_type(sdl->sdl_type) )
377 if (doing_proxy == 0) {
378 printf("set: can only proxy for %s\n", host);
381 if (dst->sin_other & SIN_PROXY) {
382 printf("set: proxy entry exists for non 802 device\n");
385 dst->sin_other = SIN_PROXY;
389 if (sdl->sdl_family != AF_LINK) {
390 printf("cannot intuit interface index and type for %s\n", host);
393 sdl_m.sdl_type = sdl->sdl_type;
394 sdl_m.sdl_index = sdl->sdl_index;
395 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL);
399 * Display an individual arp entry
404 struct sockaddr_inarp *addr;
406 addr = getaddr(host);
409 if (0 == search(addr->sin_addr.s_addr, print_entry)) {
410 printf("%s (%s) -- no entry",
411 host, inet_ntoa(addr->sin_addr));
413 printf(" on %s", rifname);
421 * Delete an arp entry
424 delete(char *host, int do_proxy)
426 struct sockaddr_inarp *addr, *dst;
427 struct rt_msghdr *rtm;
428 struct sockaddr_dl *sdl;
433 dst->sin_other = do_proxy;
434 for (;;) { /* try twice */
435 rtm = rtmsg(RTM_GET, dst, NULL);
440 addr = (struct sockaddr_inarp *)(rtm + 1);
441 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
442 if (addr->sin_addr.s_addr == dst->sin_addr.s_addr &&
443 sdl->sdl_family == AF_LINK &&
444 (rtm->rtm_flags & RTF_LLINFO) &&
445 !(rtm->rtm_flags & RTF_GATEWAY) &&
446 valid_type(sdl->sdl_type) )
447 break; /* found it */
448 if (dst->sin_other & SIN_PROXY) {
449 fprintf(stderr, "delete: cannot locate %s\n",host);
452 dst->sin_other = SIN_PROXY;
454 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) {
455 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr));
462 * Search the arp table and do some action on matching entries
465 search(u_long addr, action_fn *action)
469 char *lim, *buf, *newbuf, *next;
470 struct rt_msghdr *rtm;
471 struct sockaddr_inarp *sin2;
472 struct sockaddr_dl *sdl;
473 char ifname[IF_NAMESIZE];
474 int st, found_entry = 0;
480 mib[4] = NET_RT_FLAGS;
482 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
483 err(1, "route-sysctl-estimate");
484 if (needed == 0) /* empty table */
488 newbuf = realloc(buf, needed);
489 if (newbuf == NULL) {
492 errx(1, "could not reallocate memory");
495 st = sysctl(mib, 6, buf, &needed, NULL, 0);
496 if (st == 0 || errno != ENOMEM)
498 needed += needed / 8;
501 err(1, "actual retrieval of routing table");
503 for (next = buf; next < lim; next += rtm->rtm_msglen) {
504 rtm = (struct rt_msghdr *)next;
505 sin2 = (struct sockaddr_inarp *)(rtm + 1);
506 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
507 if (rifname && if_indextoname(sdl->sdl_index, ifname) &&
508 strcmp(ifname, rifname))
511 if (addr != sin2->sin_addr.s_addr)
515 (*action)(sdl, sin2, rtm);
518 return (found_entry);
522 * Display an arp entry
525 print_entry(struct sockaddr_dl *sdl,
526 struct sockaddr_inarp *addr, struct rt_msghdr *rtm)
530 struct iso88025_sockaddr_dl_data *trld;
531 char ifname[IF_NAMESIZE];
535 hp = gethostbyaddr((caddr_t)&(addr->sin_addr),
536 sizeof addr->sin_addr, AF_INET);
543 if (h_errno == TRY_AGAIN)
546 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr));
548 if ((sdl->sdl_type == IFT_ETHER ||
549 sdl->sdl_type == IFT_L2VLAN ||
550 sdl->sdl_type == IFT_BRIDGE) &&
551 sdl->sdl_alen == ETHER_ADDR_LEN)
552 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl)));
554 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0;
556 printf("%s", link_ntoa(sdl) + n);
559 printf("(incomplete)");
560 if (if_indextoname(sdl->sdl_index, ifname) != NULL)
561 printf(" on %s", ifname);
562 if (rtm->rtm_rmx.rmx_expire == 0)
563 printf(" permanent");
564 if (addr->sin_other & SIN_PROXY)
565 printf(" published (proxy only)");
566 if (rtm->rtm_addrs & RTA_NETMASK) {
567 addr = (struct sockaddr_inarp *)
568 (SA_SIZE(sdl) + (char *)sdl);
569 if (addr->sin_addr.s_addr == 0xffffffff)
570 printf(" published");
571 if (addr->sin_len != 8)
574 switch(sdl->sdl_type) {
576 printf(" [ethernet]");
579 printf(" [token-ring]");
580 trld = SDL_ISO88025(sdl);
581 if (trld->trld_rcf != 0) {
582 printf(" rt=%x", ntohs(trld->trld_rcf));
584 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2);
586 printf(":%x", ntohs(*(trld->trld_route[seg])));
599 printf(" [firewire]");
616 nuke_entry(struct sockaddr_dl *sdl __unused,
617 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused)
621 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
628 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
629 "usage: arp [-n] [-i interface] hostname",
630 " arp [-n] [-i interface] -a",
631 " arp -d hostname [pub]",
632 " arp -d [-i interface] -a",
633 " arp -s hostname ether_addr [temp] [reject] [blackhole] [pub [only]]",
634 " arp -S hostname ether_addr [temp] [reject] [blackhole] [pub [only]]",
639 static struct rt_msghdr *
640 rtmsg(int cmd, struct sockaddr_inarp *dst, struct sockaddr_dl *sdl)
645 struct sockaddr_in so_mask, *som = &so_mask;
650 struct rt_msghdr m_rtm;
654 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
655 char *cp = m_rtmsg.m_space;
657 if (s < 0) { /* first time: open socket, get pid */
658 s = socket(PF_ROUTE, SOCK_RAW, 0);
663 bzero(&so_mask, sizeof(so_mask));
665 so_mask.sin_addr.s_addr = 0xffffffff;
669 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer
672 if (cmd == RTM_DELETE)
674 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
675 rtm->rtm_flags = flags;
676 rtm->rtm_version = RTM_VERSION;
680 errx(1, "internal wrong cmd");
682 rtm->rtm_addrs |= RTA_GATEWAY;
683 rtm->rtm_rmx.rmx_expire = expire_time;
684 rtm->rtm_inits = RTV_EXPIRE;
685 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
689 dst->sin_other = SIN_PROXY;
691 rtm->rtm_addrs |= RTA_NETMASK;
692 rtm->rtm_flags &= ~RTF_HOST;
697 rtm->rtm_addrs |= RTA_DST;
699 #define NEXTADDR(w, s) \
700 if ((s) != NULL && rtm->rtm_addrs & (w)) { \
701 bcopy((s), cp, sizeof(*(s))); cp += SA_SIZE(s);}
703 NEXTADDR(RTA_DST, dst);
704 NEXTADDR(RTA_GATEWAY, sdl);
705 NEXTADDR(RTA_NETMASK, som);
707 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
710 rtm->rtm_seq = ++seq;
712 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
713 if (errno != ESRCH || cmd != RTM_DELETE) {
714 warn("writing to routing socket");
719 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
720 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
722 warn("read from routing socket");
727 * get_ether_addr - get the hardware address of an interface on the
728 * the same subnet as ipaddr.
733 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr)
735 struct ifreq *ifr, *ifend, *ifp;
737 struct sockaddr_dl *dla;
740 struct ifreq ifs[MAX_IFS];
744 sock = socket(AF_INET, SOCK_DGRAM, 0);
748 ifc.ifc_len = sizeof(ifs);
750 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
751 warnx("ioctl(SIOCGIFCONF)");
756 ((struct ifreq *)((char *)&(i)->ifr_addr \
757 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) )
760 * Scan through looking for an interface with an Internet
761 * address on the same subnet as `ipaddr'.
763 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len);
764 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) {
765 if (ifr->ifr_addr.sa_family != AF_INET)
767 strncpy(ifreq.ifr_name, ifr->ifr_name,
768 sizeof(ifreq.ifr_name));
769 ifreq.ifr_addr = ifr->ifr_addr;
771 * Check that the interface is up,
772 * and not point-to-point or loopback.
774 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
776 if ((ifreq.ifr_flags &
777 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
778 IFF_LOOPBACK|IFF_NOARP))
779 != (IFF_UP|IFF_BROADCAST))
782 * Get its netmask and check that it's on
785 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
787 mask = ((struct sockaddr_in *)
788 &ifreq.ifr_addr)->sin_addr.s_addr;
789 ina = ((struct sockaddr_in *)
790 &ifr->ifr_addr)->sin_addr.s_addr;
791 if ((ipaddr & mask) == (ina & mask))
792 break; /* ok, we got it! */
799 * Now scan through again looking for a link-level address
800 * for this interface.
803 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr))
804 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 &&
805 ifr->ifr_addr.sa_family == AF_LINK)
810 * Found the link-level address - copy it out
812 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
813 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
814 printf("using interface %s for proxy with address ",
816 printf("%s\n", ether_ntoa(hwaddr));
817 retval = dla->sdl_alen;