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 * 3. 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
32 * @(#) Copyright (c) 1984, 1993 The Regents of the University of California. All rights reserved.
33 * @(#)from: arp.c 8.2 (Berkeley) 1/2/94
34 * $FreeBSD: src/usr.sbin/arp/arp.c,v 1.22.2.12 2003/04/16 10:02:37 ru Exp $
38 * arp - display, set, and delete arp table entries
42 #include <sys/param.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/sysctl.h>
47 #include <sys/ioctl.h>
51 #include <net/if_dl.h>
52 #include <net/if_types.h>
53 #include <net/route.h>
55 #include <netinet/in.h>
56 #include <netinet/if_ether.h>
58 #include <arpa/inet.h>
71 void search(u_long addr, void (*action)(struct sockaddr_dl *sdl,
72 struct sockaddr_inarp *sin, struct rt_msghdr *rtm));
73 void print_entry(struct sockaddr_dl *sdl,
74 struct sockaddr_inarp *addr, struct rt_msghdr *rtm);
75 void nuke_entry(struct sockaddr_dl *sdl,
76 struct sockaddr_inarp *addr, struct rt_msghdr *rtm);
77 int delete(char *host, char *info);
79 int set(int argc, char **argv);
83 int my_ether_aton(char *a, struct ether_addr *n);
85 int get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr);
88 static int nflag; /* no reverse dns lookups */
89 static int aflag; /* do it for all entries */
90 static int cpuflag = -1;
93 struct sockaddr_in so_mask;
94 struct sockaddr_inarp blank_sin, sin_m;
95 struct sockaddr_dl blank_sdl, sdl_m;
96 int flags, doing_proxy, proxy_only, found_entry;
99 struct rt_msghdr m_rtm;
103 /* which function we're supposed to do */
110 #define SETFUNC(f) { if (func) usage(); func = (f); }
113 main(int argc, char **argv)
119 while ((ch = getopt(argc, argv, "ac:ndfsS")) != -1)
125 cpuflag = strtol(optarg, NULL, 0);
149 bzero(&so_mask, sizeof(so_mask));
151 so_mask.sin_addr.s_addr = 0xffffffff;
152 bzero(&blank_sin, sizeof(blank_sin));
153 blank_sin.sin_len = sizeof(blank_sin);
154 blank_sin.sin_family = AF_INET;
155 bzero(&blank_sdl, sizeof(blank_sdl));
156 blank_sdl.sdl_len = sizeof(blank_sdl);
157 blank_sdl.sdl_family = AF_LINK;
166 search(0, print_entry);
175 if (argc < 2 || argc > 6)
177 if (func == F_REPLACE)
178 delete(argv[0], NULL);
179 rtn = set(argc, argv) ? 1 : 0;
185 search(0, nuke_entry);
187 if (argc < 1 || argc > 2)
189 rtn = delete(argv[0], argv[1]);
203 * Process a file to set standard arp entries
210 char line[100], arg[5][50], *args[5], *p;
212 if ((fp = fopen(name, "r")) == NULL)
213 errx(1, "cannot open %s", name);
214 args[0] = &arg[0][0];
215 args[1] = &arg[1][0];
216 args[2] = &arg[2][0];
217 args[3] = &arg[3][0];
218 args[4] = &arg[4][0];
220 while(fgets(line, 100, fp) != NULL) {
221 if ((p = strchr(line, '#')) != NULL)
223 for (p = line; isblank(*p); p++);
224 if (*p == '\n' || *p == '\0')
226 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1],
227 arg[2], arg[3], arg[4]);
229 warnx("bad line: %s", line);
244 s = socket(PF_ROUTE, SOCK_RAW, 0);
251 * Set an individual arp entry
254 set(int argc, char **argv)
257 struct sockaddr_inarp *addr = &sin_m;
258 struct sockaddr_dl *sdl;
259 struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
260 struct ether_addr *ea;
261 char *host = argv[0], *eaddr = argv[1];
268 addr->sin_addr.s_addr = inet_addr(host);
269 if (addr->sin_addr.s_addr == INADDR_NONE) {
270 if (!(hp = gethostbyname(host))) {
271 warnx("%s: %s", host, hstrerror(h_errno));
274 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
275 sizeof(addr->sin_addr));
277 doing_proxy = flags = proxy_only = expire_time = 0;
279 if (strncmp(argv[0], "temp", 4) == 0) {
282 clock_gettime(CLOCK_MONOTONIC, &sp);
283 expire_time = sp.tv_sec + 20 * 60;
285 else if (strncmp(argv[0], "pub", 3) == 0) {
286 flags |= RTF_ANNOUNCE;
288 if (argc && strncmp(argv[1], "only", 3) == 0) {
290 sin_m.sin_other = SIN_PROXY;
293 } else if (strncmp(argv[0], "trail", 5) == 0) {
294 printf("%s: Sending trailers is no longer supported\n",
299 ea = (struct ether_addr *)LLADDR(&sdl_m);
300 if (doing_proxy && !strcmp(eaddr, "auto")) {
301 if (!get_ether_addr(addr->sin_addr.s_addr, ea)) {
302 printf("no interface found for %s\n",
303 inet_ntoa(addr->sin_addr));
306 sdl_m.sdl_alen = ETHER_ADDR_LEN;
308 if (my_ether_aton(eaddr, ea) == 0)
309 sdl_m.sdl_alen = ETHER_ADDR_LEN;
312 if (rtmsg(RTM_GET) < 0) {
316 addr = (struct sockaddr_inarp *)(rtm + 1);
317 sdl = (struct sockaddr_dl *)(RT_ROUNDUP(addr->sin_len) + (char *)addr);
318 if (addr->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
319 if (sdl->sdl_family == AF_LINK &&
320 (rtm->rtm_flags & RTF_LLINFO) &&
321 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
322 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
323 case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN:
327 if (doing_proxy == 0) {
328 printf("set: can only proxy for %s\n", host);
331 if (sin_m.sin_other & SIN_PROXY) {
332 printf("set: proxy entry exists for non 802 device\n");
335 sin_m.sin_other = SIN_PROXY;
340 if (sdl->sdl_family != AF_LINK) {
341 printf("cannot intuit interface index and type for %s\n", host);
344 sdl_m.sdl_type = sdl->sdl_type;
345 sdl_m.sdl_index = sdl->sdl_index;
346 return(rtmsg(RTM_ADD));
350 * Display an individual arp entry
356 struct sockaddr_inarp *addr = &sin_m;
359 addr->sin_addr.s_addr = inet_addr(host);
360 if (addr->sin_addr.s_addr == INADDR_NONE) {
361 if (!(hp = gethostbyname(host)))
362 errx(1, "%s: %s", host, hstrerror(h_errno));
363 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
364 sizeof(addr->sin_addr));
366 search(addr->sin_addr.s_addr, print_entry);
367 if (found_entry == 0) {
368 printf("%s (%s) -- no entry\n",
369 host, inet_ntoa(addr->sin_addr));
376 * Delete an arp entry
379 delete(char *host, char *info)
382 struct sockaddr_inarp *addr = &sin_m;
383 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
384 struct sockaddr_dl *sdl;
389 if (strncmp(info, "pub", 3) == 0)
390 sin_m.sin_other = SIN_PROXY;
394 addr->sin_addr.s_addr = inet_addr(host);
395 if (addr->sin_addr.s_addr == INADDR_NONE) {
396 if (!(hp = gethostbyname(host))) {
397 warnx("%s: %s", host, hstrerror(h_errno));
400 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
401 sizeof(addr->sin_addr));
404 if (rtmsg(RTM_GET) < 0) {
408 addr = (struct sockaddr_inarp *)(rtm + 1);
409 sdl = (struct sockaddr_dl *)(RT_ROUNDUP(addr->sin_len) + (char *)addr);
410 if (addr->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
411 if (sdl->sdl_family == AF_LINK &&
412 (rtm->rtm_flags & RTF_LLINFO) &&
413 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
414 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
415 case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN:
420 if (sin_m.sin_other & SIN_PROXY) {
421 fprintf(stderr, "delete: can't locate %s\n",host);
424 sin_m.sin_other = SIN_PROXY;
428 if (sdl->sdl_family != AF_LINK) {
429 printf("cannot locate %s\n", host);
432 if (aflag && (rtm->rtm_flags & RTF_STATIC)) {
435 if (rtmsg(RTM_CHANGE) == 0) {
436 printf("%s (%s) cleared\n",
437 host, inet_ntoa(addr->sin_addr));
441 if (rtmsg(RTM_DELETE) == 0) {
442 printf("%s (%s) deleted\n",
443 host, inet_ntoa(addr->sin_addr));
451 * Search the arp table and do some action on matching entries
454 search(u_long addr, void (*action)(struct sockaddr_dl *sdl,
455 struct sockaddr_inarp *sin, struct rt_msghdr *rtm))
460 char *lim, *buf, *next;
461 struct rt_msghdr *rtm;
462 struct sockaddr_inarp *sin2;
463 struct sockaddr_dl *sdl;
469 mib[4] = NET_RT_FLAGS;
477 if (sysctl(mib, miblen, NULL, &needed, NULL, 0) < 0)
478 errx(1, "route-sysctl-estimate");
479 if ((buf = malloc(needed)) == NULL)
481 if (sysctl(mib, miblen, buf, &needed, NULL, 0) < 0)
482 errx(1, "actual retrieval of routing table");
484 for (next = buf; next < lim; next += rtm->rtm_msglen) {
485 rtm = (struct rt_msghdr *)next;
486 sin2 = (struct sockaddr_inarp *)(rtm + 1);
487 sdl = (struct sockaddr_dl *)((char *)sin2 +
488 RT_ROUNDUP(sin2->sin_len));
490 if (addr != sin2->sin_addr.s_addr)
494 (*action)(sdl, sin2, rtm);
500 * Display an arp entry
503 print_entry(struct sockaddr_dl *sdl,
504 struct sockaddr_inarp *addr, struct rt_msghdr *rtm)
508 char ifname[IF_NAMESIZE];
511 hp = gethostbyaddr(&(addr->sin_addr), sizeof(addr->sin_addr),
519 if (h_errno == TRY_AGAIN)
522 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr));
524 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl)));
526 printf("(incomplete)");
527 if (if_indextoname(sdl->sdl_index, ifname) != NULL)
528 printf(" on %s", ifname);
529 if (rtm->rtm_rmx.rmx_expire == 0)
530 printf(" permanent");
531 if (addr->sin_other & SIN_PROXY)
532 printf(" published (proxy only)");
533 if (rtm->rtm_addrs & RTA_NETMASK) {
534 addr = (struct sockaddr_inarp *)
535 (RT_ROUNDUP(sdl->sdl_len) + (char *)sdl);
536 if (addr->sin_addr.s_addr == 0xffffffff)
537 printf(" published");
538 if (addr->sin_len != 8)
541 switch(sdl->sdl_type) {
543 printf(" [ethernet]");
562 nuke_entry(struct sockaddr_dl *sdl __unused,
563 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused)
567 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
572 my_ether_aton(char *a, struct ether_addr *n)
574 struct ether_addr *ea;
576 if ((ea = ether_aton(a)) == NULL) {
577 warnx("invalid Ethernet address '%s'", a);
587 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
588 "usage: arp [-n] [-c cpu] hostname",
589 " arp [-n] [-c cpu] -a",
590 " arp -d hostname [pub]",
592 " arp -s hostname ether_addr [temp] [pub [only]]",
593 " arp -S hostname ether_addr [temp] [pub [only]]",
603 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
604 char *cp = m_rtmsg.m_space;
608 if (cmd == RTM_DELETE || cmd == RTM_CHANGE)
610 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
611 rtm->rtm_flags = flags;
612 rtm->rtm_version = RTM_VERSION;
616 errx(1, "internal wrong cmd");
618 rtm->rtm_addrs |= RTA_GATEWAY;
619 rtm->rtm_rmx.rmx_expire = expire_time;
620 rtm->rtm_inits = RTV_EXPIRE;
621 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
625 sin_m.sin_other = SIN_PROXY;
627 rtm->rtm_addrs |= RTA_NETMASK;
628 rtm->rtm_flags &= ~RTF_HOST;
633 rtm->rtm_addrs |= RTA_DST;
636 #define NEXTADDR(w, s) \
637 if (rtm->rtm_addrs & (w)) { \
638 bcopy((char *)&s, cp, sizeof(s)); \
639 cp += RT_ROUNDUP(sizeof(s)); \
642 NEXTADDR(RTA_DST, sin_m);
643 NEXTADDR(RTA_GATEWAY, sdl_m);
644 NEXTADDR(RTA_NETMASK, so_mask);
646 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
649 rtm->rtm_seq = ++seq;
651 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
652 if (errno != ESRCH || (cmd != RTM_DELETE && cmd != RTM_CHANGE)) {
653 warn("writing to routing socket");
658 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
659 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
661 warn("read from routing socket");
666 * get_ether_addr - get the hardware address of an interface on the
667 * the same subnet as ipaddr.
672 get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr)
674 struct ifreq *ifr, *ifend, *ifp;
676 struct sockaddr_dl *dla;
679 struct ifreq ifs[MAX_IFS];
682 sock = socket(AF_INET, SOCK_DGRAM, 0);
686 ifc.ifc_len = sizeof(ifs);
688 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
689 warnx("ioctl(SIOCGIFCONF)");
695 * Scan through looking for an interface with an Internet
696 * address on the same subnet as `ipaddr'.
698 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
699 for (ifr = ifc.ifc_req; ifr < ifend; ) {
700 if (ifr->ifr_addr.sa_family == AF_INET) {
701 ina = ((struct sockaddr_in *)
702 &ifr->ifr_addr)->sin_addr.s_addr;
703 strncpy(ifreq.ifr_name, ifr->ifr_name,
704 sizeof(ifreq.ifr_name));
706 * Check that the interface is up,
707 * and not point-to-point or loopback.
709 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
711 if ((ifreq.ifr_flags &
712 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
713 IFF_LOOPBACK|IFF_NOARP))
714 != (IFF_UP|IFF_BROADCAST))
717 * Get its netmask and check that it's on
720 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
722 mask = ((struct sockaddr_in *)
723 &ifreq.ifr_addr)->sin_addr.s_addr;
724 if ((ipaddr & mask) != (ina & mask))
729 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr
730 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr)));
739 * Now scan through again looking for a link-level address
740 * for this interface.
743 for (ifr = ifc.ifc_req; ifr < ifend; ) {
744 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
745 && ifr->ifr_addr.sa_family == AF_LINK) {
747 * Found the link-level address - copy it out
749 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
750 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
752 printf("using interface %s for proxy with address ",
754 printf("%s\n", ether_ntoa(hwaddr));
755 return(dla->sdl_alen);
757 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr
758 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr)));