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;
325 else if (strncmp(argv[0], "pub", 3) == 0) {
326 flags |= RTF_ANNOUNCE;
328 if (argc && strncmp(argv[1], "only", 3) == 0) {
330 dst->sin_other = SIN_PROXY;
333 } else if (strncmp(argv[0], "trail", 5) == 0) {
334 /* XXX deprecated and undocumented feature */
335 printf("%s: Sending trailers is no longer supported\n",
340 ea = (struct ether_addr *)LLADDR(&sdl_m);
341 if (doing_proxy && !strcmp(eaddr, "auto")) {
342 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) {
343 printf("no interface found for %s\n",
344 inet_ntoa(dst->sin_addr));
347 sdl_m.sdl_alen = ETHER_ADDR_LEN;
349 struct ether_addr *ea1 = ether_aton(eaddr);
352 warnx("invalid Ethernet address '%s'", eaddr);
356 sdl_m.sdl_alen = ETHER_ADDR_LEN;
359 for (;;) { /* try at most twice */
360 rtm = rtmsg(RTM_GET, dst, &sdl_m);
365 addr = (struct sockaddr_inarp *)(rtm + 1);
366 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
367 if (addr->sin_addr.s_addr != dst->sin_addr.s_addr)
369 if (sdl->sdl_family == AF_LINK &&
370 (rtm->rtm_flags & RTF_LLINFO) &&
371 !(rtm->rtm_flags & RTF_GATEWAY) &&
372 valid_type(sdl->sdl_type) )
374 if (doing_proxy == 0) {
375 printf("set: can only proxy for %s\n", host);
378 if (dst->sin_other & SIN_PROXY) {
379 printf("set: proxy entry exists for non 802 device\n");
382 dst->sin_other = SIN_PROXY;
386 if (sdl->sdl_family != AF_LINK) {
387 printf("cannot intuit interface index and type for %s\n", host);
390 sdl_m.sdl_type = sdl->sdl_type;
391 sdl_m.sdl_index = sdl->sdl_index;
392 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL);
396 * Display an individual arp entry
401 struct sockaddr_inarp *addr;
403 addr = getaddr(host);
406 if (0 == search(addr->sin_addr.s_addr, print_entry)) {
407 printf("%s (%s) -- no entry",
408 host, inet_ntoa(addr->sin_addr));
410 printf(" on %s", rifname);
418 * Delete an arp entry
421 delete(char *host, int do_proxy)
423 struct sockaddr_inarp *addr, *dst;
424 struct rt_msghdr *rtm;
425 struct sockaddr_dl *sdl;
430 dst->sin_other = do_proxy;
431 for (;;) { /* try twice */
432 rtm = rtmsg(RTM_GET, dst, NULL);
437 addr = (struct sockaddr_inarp *)(rtm + 1);
438 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
439 if (addr->sin_addr.s_addr == dst->sin_addr.s_addr &&
440 sdl->sdl_family == AF_LINK &&
441 (rtm->rtm_flags & RTF_LLINFO) &&
442 !(rtm->rtm_flags & RTF_GATEWAY) &&
443 valid_type(sdl->sdl_type) )
444 break; /* found it */
445 if (dst->sin_other & SIN_PROXY) {
446 fprintf(stderr, "delete: cannot locate %s\n",host);
449 dst->sin_other = SIN_PROXY;
451 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) {
452 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr));
459 * Search the arp table and do some action on matching entries
462 search(u_long addr, action_fn *action)
466 char *lim, *buf, *newbuf, *next;
467 struct rt_msghdr *rtm;
468 struct sockaddr_inarp *sin2;
469 struct sockaddr_dl *sdl;
470 char ifname[IF_NAMESIZE];
471 int st, found_entry = 0;
477 mib[4] = NET_RT_FLAGS;
479 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
480 err(1, "route-sysctl-estimate");
481 if (needed == 0) /* empty table */
485 newbuf = realloc(buf, needed);
486 if (newbuf == NULL) {
489 errx(1, "could not reallocate memory");
492 st = sysctl(mib, 6, buf, &needed, NULL, 0);
493 if (st == 0 || errno != ENOMEM)
495 needed += needed / 8;
498 err(1, "actual retrieval of routing table");
500 for (next = buf; next < lim; next += rtm->rtm_msglen) {
501 rtm = (struct rt_msghdr *)next;
502 sin2 = (struct sockaddr_inarp *)(rtm + 1);
503 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
504 if (rifname && if_indextoname(sdl->sdl_index, ifname) &&
505 strcmp(ifname, rifname))
508 if (addr != sin2->sin_addr.s_addr)
512 (*action)(sdl, sin2, rtm);
515 return (found_entry);
519 * Display an arp entry
522 print_entry(struct sockaddr_dl *sdl,
523 struct sockaddr_inarp *addr, struct rt_msghdr *rtm)
527 struct iso88025_sockaddr_dl_data *trld;
528 char ifname[IF_NAMESIZE];
532 hp = gethostbyaddr((caddr_t)&(addr->sin_addr),
533 sizeof addr->sin_addr, AF_INET);
540 if (h_errno == TRY_AGAIN)
543 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr));
545 if ((sdl->sdl_type == IFT_ETHER ||
546 sdl->sdl_type == IFT_L2VLAN ||
547 sdl->sdl_type == IFT_BRIDGE) &&
548 sdl->sdl_alen == ETHER_ADDR_LEN)
549 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl)));
551 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0;
553 printf("%s", link_ntoa(sdl) + n);
556 printf("(incomplete)");
557 if (if_indextoname(sdl->sdl_index, ifname) != NULL)
558 printf(" on %s", ifname);
559 if (rtm->rtm_rmx.rmx_expire == 0)
560 printf(" permanent");
561 if (addr->sin_other & SIN_PROXY)
562 printf(" published (proxy only)");
563 if (rtm->rtm_addrs & RTA_NETMASK) {
564 addr = (struct sockaddr_inarp *)
565 (SA_SIZE(sdl) + (char *)sdl);
566 if (addr->sin_addr.s_addr == 0xffffffff)
567 printf(" published");
568 if (addr->sin_len != 8)
571 switch(sdl->sdl_type) {
573 printf(" [ethernet]");
576 printf(" [token-ring]");
577 trld = SDL_ISO88025(sdl);
578 if (trld->trld_rcf != 0) {
579 printf(" rt=%x", ntohs(trld->trld_rcf));
581 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2);
583 printf(":%x", ntohs(*(trld->trld_route[seg])));
596 printf(" [firewire]");
613 nuke_entry(struct sockaddr_dl *sdl __unused,
614 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused)
618 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
625 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
626 "usage: arp [-n] [-i interface] hostname",
627 " arp [-n] [-i interface] -a",
628 " arp -d hostname [pub]",
629 " arp -d [-i interface] -a",
630 " arp -s hostname ether_addr [temp] [pub [only]]",
631 " arp -S hostname ether_addr [temp] [pub [only]]",
636 static struct rt_msghdr *
637 rtmsg(int cmd, struct sockaddr_inarp *dst, struct sockaddr_dl *sdl)
642 struct sockaddr_in so_mask;
647 struct rt_msghdr m_rtm;
651 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
652 char *cp = m_rtmsg.m_space;
654 if (s < 0) { /* first time: open socket, get pid */
655 s = socket(PF_ROUTE, SOCK_RAW, 0);
660 bzero(&so_mask, sizeof(so_mask));
662 so_mask.sin_addr.s_addr = 0xffffffff;
666 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer
669 if (cmd == RTM_DELETE)
671 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
672 rtm->rtm_flags = flags;
673 rtm->rtm_version = RTM_VERSION;
677 errx(1, "internal wrong cmd");
679 rtm->rtm_addrs |= RTA_GATEWAY;
680 rtm->rtm_rmx.rmx_expire = expire_time;
681 rtm->rtm_inits = RTV_EXPIRE;
682 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
686 dst->sin_other = SIN_PROXY;
688 rtm->rtm_addrs |= RTA_NETMASK;
689 rtm->rtm_flags &= ~RTF_HOST;
694 rtm->rtm_addrs |= RTA_DST;
696 #define NEXTADDR(w, s) \
697 if ((s) != NULL && rtm->rtm_addrs & (w)) { \
698 bcopy((s), cp, sizeof(*(s))); cp += SA_SIZE(s);}
700 NEXTADDR(RTA_DST, dst);
701 NEXTADDR(RTA_GATEWAY, sdl);
702 NEXTADDR(RTA_NETMASK, &so_mask);
704 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
707 rtm->rtm_seq = ++seq;
709 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
710 if (errno != ESRCH || cmd != RTM_DELETE) {
711 warn("writing to routing socket");
716 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
717 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
719 warn("read from routing socket");
724 * get_ether_addr - get the hardware address of an interface on the
725 * the same subnet as ipaddr.
730 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr)
732 struct ifreq *ifr, *ifend, *ifp;
734 struct sockaddr_dl *dla;
737 struct ifreq ifs[MAX_IFS];
741 sock = socket(AF_INET, SOCK_DGRAM, 0);
745 ifc.ifc_len = sizeof(ifs);
747 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
748 warnx("ioctl(SIOCGIFCONF)");
753 ((struct ifreq *)((char *)&(i)->ifr_addr \
754 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) )
757 * Scan through looking for an interface with an Internet
758 * address on the same subnet as `ipaddr'.
760 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len);
761 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) {
762 if (ifr->ifr_addr.sa_family != AF_INET)
764 strncpy(ifreq.ifr_name, ifr->ifr_name,
765 sizeof(ifreq.ifr_name));
766 ifreq.ifr_addr = ifr->ifr_addr;
768 * Check that the interface is up,
769 * and not point-to-point or loopback.
771 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
773 if ((ifreq.ifr_flags &
774 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
775 IFF_LOOPBACK|IFF_NOARP))
776 != (IFF_UP|IFF_BROADCAST))
779 * Get its netmask and check that it's on
782 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
784 mask = ((struct sockaddr_in *)
785 &ifreq.ifr_addr)->sin_addr.s_addr;
786 ina = ((struct sockaddr_in *)
787 &ifr->ifr_addr)->sin_addr.s_addr;
788 if ((ipaddr & mask) == (ina & mask))
789 break; /* ok, we got it! */
796 * Now scan through again looking for a link-level address
797 * for this interface.
800 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr))
801 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 &&
802 ifr->ifr_addr.sa_family == AF_LINK)
807 * Found the link-level address - copy it out
809 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
810 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
811 printf("using interface %s for proxy with address ",
813 printf("%s\n", ether_ntoa(hwaddr));
814 retval = dla->sdl_alen;