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 * @(#)from: arp.c 8.2 (Berkeley) 1/2/94
33 * $FreeBSD: src/usr.sbin/arp/arp.c,v 1.22.2.12 2003/04/16 10:02:37 ru Exp $
37 * arp - display, set, and delete arp table entries
41 #include <sys/param.h>
43 #include <sys/socket.h>
44 #include <sys/sockio.h>
45 #include <sys/sysctl.h>
46 #include <sys/ioctl.h>
50 #include <net/if_dl.h>
51 #include <net/if_types.h>
52 #include <net/route.h>
54 #include <netinet/in.h>
55 #include <netinet/if_ether.h>
57 #include <arpa/inet.h>
70 static void search(u_long addr, void (*action)(struct sockaddr_dl *sdl,
71 struct sockaddr_inarp *sin, struct rt_msghdr *rtm));
72 static void print_entry(struct sockaddr_dl *sdl,
73 struct sockaddr_inarp *addr, struct rt_msghdr *rtm);
74 static void nuke_entry(struct sockaddr_dl *sdl,
75 struct sockaddr_inarp *addr, struct rt_msghdr *rtm);
76 static int delete(char *host, char *info);
77 static void usage(void) __dead2;
78 static int set(int argc, char **argv);
79 static int get(char *host);
80 static int file(char *name);
81 static void getsocket(void);
82 static int my_ether_aton(char *a, struct ether_addr *n);
83 static int rtmsg(int cmd);
84 static int get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr);
87 static int nflag; /* no reverse dns lookups */
88 static int aflag; /* do it for all entries */
89 static int cpuflag = -1;
91 static int rifindex = 0;
92 static const char *rifname = NULL;
94 static struct sockaddr_in so_mask;
95 static struct sockaddr_inarp blank_sin, sin_m;
96 static struct sockaddr_dl blank_sdl, sdl_m;
97 static int flags, doing_proxy, proxy_only, found_entry;
98 static time_t expire_time;
100 struct rt_msghdr m_rtm;
104 /* which function we're supposed to do */
111 #define SETFUNC(f) { if (func) usage(); func = (f); }
114 main(int argc, char **argv)
120 while ((ch = getopt(argc, argv, "ac:i:ndfsS")) != -1)
126 cpuflag = strtol(optarg, NULL, 0);
153 bzero(&so_mask, sizeof(so_mask));
155 so_mask.sin_addr.s_addr = 0xffffffff;
156 bzero(&blank_sin, sizeof(blank_sin));
157 blank_sin.sin_len = sizeof(blank_sin);
158 blank_sin.sin_family = AF_INET;
159 bzero(&blank_sdl, sizeof(blank_sdl));
160 blank_sdl.sdl_len = sizeof(blank_sdl);
161 blank_sdl.sdl_family = AF_LINK;
165 if (rifname != NULL) {
166 if (func != F_GET && !(func == F_DELETE && aflag))
167 errx(1, "-i not applicable to this operation");
168 if ((rifindex = if_nametoindex(rifname)) == 0) {
170 errx(1, "interface %s does not exist",
173 err(1, "if_nametoindex(%s)", rifname);
182 search(0, print_entry);
191 if (argc < 2 || argc > 6)
193 if (func == F_REPLACE)
194 delete(argv[0], NULL);
195 rtn = set(argc, argv) ? 1 : 0;
201 search(0, nuke_entry);
203 if (argc < 1 || argc > 2)
205 rtn = delete(argv[0], argv[1]);
219 * Process a file to set standard arp entries
226 char line[100], arg[5][50], *args[5], *p;
228 if ((fp = fopen(name, "r")) == NULL)
229 errx(1, "cannot open %s", name);
230 args[0] = &arg[0][0];
231 args[1] = &arg[1][0];
232 args[2] = &arg[2][0];
233 args[3] = &arg[3][0];
234 args[4] = &arg[4][0];
236 while(fgets(line, 100, fp) != NULL) {
237 if ((p = strchr(line, '#')) != NULL)
239 for (p = line; isblank(*p); p++);
240 if (*p == '\n' || *p == '\0')
242 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1],
243 arg[2], arg[3], arg[4]);
245 warnx("bad line: %s", line);
260 s = socket(PF_ROUTE, SOCK_RAW, 0);
267 * Set an individual arp entry
270 set(int argc, char **argv)
273 struct sockaddr_inarp *addr = &sin_m;
274 struct sockaddr_dl *sdl;
275 struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
276 struct ether_addr *ea;
277 char *host = argv[0], *eaddr = argv[1];
284 addr->sin_addr.s_addr = inet_addr(host);
285 if (addr->sin_addr.s_addr == INADDR_NONE) {
286 if (!(hp = gethostbyname(host))) {
287 warnx("%s: %s", host, hstrerror(h_errno));
290 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
291 sizeof(addr->sin_addr));
293 doing_proxy = flags = proxy_only = expire_time = 0;
295 if (strncmp(argv[0], "temp", 4) == 0) {
298 clock_gettime(CLOCK_MONOTONIC, &sp);
299 expire_time = sp.tv_sec + 20 * 60;
301 else if (strncmp(argv[0], "pub", 3) == 0) {
302 flags |= RTF_ANNOUNCE;
304 if (argc && strncmp(argv[1], "only", 3) == 0) {
306 sin_m.sin_other = SIN_PROXY;
309 } else if (strncmp(argv[0], "trail", 5) == 0) {
310 printf("%s: Sending trailers is no longer supported\n",
315 ea = (struct ether_addr *)LLADDR(&sdl_m);
316 if (doing_proxy && !strcmp(eaddr, "auto")) {
317 if (!get_ether_addr(addr->sin_addr.s_addr, ea)) {
318 printf("no interface found for %s\n",
319 inet_ntoa(addr->sin_addr));
322 sdl_m.sdl_alen = ETHER_ADDR_LEN;
324 if (my_ether_aton(eaddr, ea) == 0)
325 sdl_m.sdl_alen = ETHER_ADDR_LEN;
328 if (rtmsg(RTM_GET) < 0) {
332 addr = (struct sockaddr_inarp *)(rtm + 1);
333 sdl = (struct sockaddr_dl *)(RT_ROUNDUP(addr->sin_len) + (char *)addr);
334 if (addr->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
335 if (sdl->sdl_family == AF_LINK &&
336 (rtm->rtm_flags & RTF_LLINFO) &&
337 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
338 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
339 case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN:
343 if (doing_proxy == 0) {
344 printf("set: can only proxy for %s\n", host);
347 if (sin_m.sin_other & SIN_PROXY) {
348 printf("set: proxy entry exists for non 802 device\n");
351 sin_m.sin_other = SIN_PROXY;
356 if (sdl->sdl_family != AF_LINK) {
357 printf("cannot intuit interface index and type for %s\n", host);
360 sdl_m.sdl_type = sdl->sdl_type;
361 sdl_m.sdl_index = sdl->sdl_index;
362 return(rtmsg(RTM_ADD));
366 * Display an individual arp entry
372 struct sockaddr_inarp *addr = &sin_m;
375 addr->sin_addr.s_addr = inet_addr(host);
376 if (addr->sin_addr.s_addr == INADDR_NONE) {
377 if (!(hp = gethostbyname(host)))
378 errx(1, "%s: %s", host, hstrerror(h_errno));
379 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
380 sizeof(addr->sin_addr));
382 search(addr->sin_addr.s_addr, print_entry);
383 if (found_entry == 0) {
384 printf("%s (%s) -- no entry",
385 host, inet_ntoa(addr->sin_addr));
387 printf(" on %s", rifname);
395 * Delete an arp entry
398 delete(char *host, char *info)
401 struct sockaddr_inarp *addr = &sin_m;
402 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
403 struct sockaddr_dl *sdl;
408 if (strncmp(info, "pub", 3) == 0)
409 sin_m.sin_other = SIN_PROXY;
413 addr->sin_addr.s_addr = inet_addr(host);
414 if (addr->sin_addr.s_addr == INADDR_NONE) {
415 if (!(hp = gethostbyname(host))) {
416 warnx("%s: %s", host, hstrerror(h_errno));
419 bcopy((char *)hp->h_addr, (char *)&addr->sin_addr,
420 sizeof(addr->sin_addr));
423 if (rtmsg(RTM_GET) < 0) {
427 addr = (struct sockaddr_inarp *)(rtm + 1);
428 sdl = (struct sockaddr_dl *)(RT_ROUNDUP(addr->sin_len) + (char *)addr);
429 if (addr->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
430 if (sdl->sdl_family == AF_LINK &&
431 (rtm->rtm_flags & RTF_LLINFO) &&
432 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
433 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
434 case IFT_ISO88024: case IFT_ISO88025: case IFT_L2VLAN:
439 if (sin_m.sin_other & SIN_PROXY) {
440 fprintf(stderr, "delete: can't locate %s\n",host);
443 sin_m.sin_other = SIN_PROXY;
447 if (sdl->sdl_family != AF_LINK) {
448 printf("cannot locate %s\n", host);
451 if (aflag && (rtm->rtm_flags & RTF_STATIC)) {
454 if (rtmsg(RTM_CHANGE) == 0) {
455 printf("%s (%s) cleared\n",
456 host, inet_ntoa(addr->sin_addr));
460 if (rtmsg(RTM_DELETE) == 0) {
461 printf("%s (%s) deleted\n",
462 host, inet_ntoa(addr->sin_addr));
470 * Search the arp table and do some action on matching entries
473 search(u_long addr, void (*action)(struct sockaddr_dl *sdl,
474 struct sockaddr_inarp *sin, struct rt_msghdr *rtm))
479 char *lim, *buf, *next;
480 struct rt_msghdr *rtm;
481 struct sockaddr_inarp *sin2;
482 struct sockaddr_dl *sdl;
488 mib[4] = NET_RT_FLAGS;
496 if (sysctl(mib, miblen, NULL, &needed, NULL, 0) < 0)
497 errx(1, "route-sysctl-estimate");
498 if ((buf = malloc(needed)) == NULL)
500 if (sysctl(mib, miblen, buf, &needed, NULL, 0) < 0)
501 errx(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 +
507 RT_ROUNDUP(sin2->sin_len));
508 if (rifindex > 0 && rifindex != sdl->sdl_index)
511 if (addr != sin2->sin_addr.s_addr)
515 (*action)(sdl, sin2, rtm);
521 * Display an arp entry
524 print_entry(struct sockaddr_dl *sdl,
525 struct sockaddr_inarp *addr, struct rt_msghdr *rtm)
529 char ifname[IF_NAMESIZE];
532 hp = gethostbyaddr(&(addr->sin_addr), sizeof(addr->sin_addr),
540 if (h_errno == TRY_AGAIN)
543 printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr));
545 printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl)));
547 printf("(incomplete)");
548 if (if_indextoname(sdl->sdl_index, ifname) != NULL)
549 printf(" on %s", ifname);
550 if (rtm->rtm_rmx.rmx_expire == 0)
551 printf(" permanent");
552 if (addr->sin_other & SIN_PROXY)
553 printf(" published (proxy only)");
554 if (rtm->rtm_addrs & RTA_NETMASK) {
555 addr = (struct sockaddr_inarp *)
556 (RT_ROUNDUP(sdl->sdl_len) + (char *)sdl);
557 if (addr->sin_addr.s_addr == 0xffffffff)
558 printf(" published");
559 if (addr->sin_len != 8)
562 switch(sdl->sdl_type) {
564 printf(" [ethernet]");
583 nuke_entry(struct sockaddr_dl *sdl __unused,
584 struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused)
588 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
593 my_ether_aton(char *a, struct ether_addr *n)
595 struct ether_addr *ea;
597 if ((ea = ether_aton(a)) == NULL) {
598 warnx("invalid Ethernet address '%s'", a);
608 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
609 "usage: arp [-n] [-c cpu] [-i interface] hostname",
610 " arp [-n] [-c cpu] [-i interface] -a",
611 " arp -d hostname [pub]",
612 " arp -d [-i interface] -a",
613 " arp -s hostname ether_addr [temp] [pub [only]]",
614 " arp -S hostname ether_addr [temp] [pub [only]]",
624 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
625 char *cp = m_rtmsg.m_space;
629 if (cmd == RTM_DELETE || cmd == RTM_CHANGE)
631 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
632 rtm->rtm_flags = flags;
633 rtm->rtm_version = RTM_VERSION;
637 errx(1, "internal wrong cmd");
639 rtm->rtm_addrs |= RTA_GATEWAY;
640 rtm->rtm_rmx.rmx_expire = expire_time;
641 rtm->rtm_inits = RTV_EXPIRE;
642 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
646 sin_m.sin_other = SIN_PROXY;
648 rtm->rtm_addrs |= RTA_NETMASK;
649 rtm->rtm_flags &= ~RTF_HOST;
654 rtm->rtm_addrs |= RTA_DST;
657 #define NEXTADDR(w, s) \
658 if (rtm->rtm_addrs & (w)) { \
659 bcopy((char *)&s, cp, sizeof(s)); \
660 cp += RT_ROUNDUP(sizeof(s)); \
663 NEXTADDR(RTA_DST, sin_m);
664 NEXTADDR(RTA_GATEWAY, sdl_m);
665 NEXTADDR(RTA_NETMASK, so_mask);
667 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
670 rtm->rtm_seq = ++seq;
672 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
673 if (errno != ESRCH || (cmd != RTM_DELETE && cmd != RTM_CHANGE)) {
674 warn("writing to routing socket");
679 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
680 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
682 warn("read from routing socket");
687 * get_ether_addr - get the hardware address of an interface on the
688 * the same subnet as ipaddr.
693 get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr)
695 struct ifreq *ifr, *ifend, *ifp;
697 struct sockaddr_dl *dla;
700 struct ifreq ifs[MAX_IFS];
703 sock = socket(AF_INET, SOCK_DGRAM, 0);
707 ifc.ifc_len = sizeof(ifs);
709 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
710 warnx("ioctl(SIOCGIFCONF)");
716 * Scan through looking for an interface with an Internet
717 * address on the same subnet as `ipaddr'.
719 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
720 for (ifr = ifc.ifc_req; ifr < ifend; ) {
721 if (ifr->ifr_addr.sa_family == AF_INET) {
722 ina = ((struct sockaddr_in *)
723 &ifr->ifr_addr)->sin_addr.s_addr;
724 strncpy(ifreq.ifr_name, ifr->ifr_name,
725 sizeof(ifreq.ifr_name));
727 * Check that the interface is up,
728 * and not point-to-point or loopback.
730 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
732 if ((ifreq.ifr_flags &
733 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
734 IFF_LOOPBACK|IFF_NOARP))
735 != (IFF_UP|IFF_BROADCAST))
738 * Get its netmask and check that it's on
741 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
743 mask = ((struct sockaddr_in *)
744 &ifreq.ifr_addr)->sin_addr.s_addr;
745 if ((ipaddr & mask) != (ina & mask))
750 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr
751 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr)));
760 * Now scan through again looking for a link-level address
761 * for this interface.
764 for (ifr = ifc.ifc_req; ifr < ifend; ) {
765 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
766 && ifr->ifr_addr.sa_family == AF_LINK) {
768 * Found the link-level address - copy it out
770 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
771 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
773 printf("using interface %s for proxy with address ",
775 printf("%s\n", ether_ntoa(hwaddr));
776 return(dla->sdl_alen);
778 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr
779 + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr)));