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
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
51 #include <sys/param.h>
53 #include <sys/socket.h>
54 #include <sys/sockio.h>
55 #include <sys/sysctl.h>
56 #include <sys/ioctl.h>
60 #include <net/if_dl.h>
61 #include <net/if_types.h>
62 #include <net/route.h>
63 #include <net/iso88025.h>
65 #include <netinet/in.h>
66 #include <netinet/if_ether.h>
68 #include <arpa/inet.h>
83 typedef void (action_fn)(struct sockaddr_dl *sdl, struct sockaddr_in *s_in,
84 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);
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_in *dst, struct sockaddr_dl *sdl);
97 static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr);
98 static struct sockaddr_in *getaddr(char *host);
99 static int valid_type(int type);
101 static int nflag; /* no reverse dns lookups */
102 static char *rifname;
104 static time_t expire_time;
105 static int flags, doing_proxy;
107 struct if_nameindex *ifnameindex;
109 /* which function we're supposed to do */
116 #define SETFUNC(f) { if (func) usage(); func = (f); }
118 #define ARP_XO_VERSION "1"
121 main(int argc, char *argv[])
125 int aflag = 0; /* do it for all entries */
127 argc = xo_parse_args(argc, argv);
131 while ((ch = getopt(argc, argv, "andfsSi:")) != -1)
164 if (func != F_GET && !(func == F_DELETE && aflag))
165 xo_errx(1, "-i not applicable to this operation");
166 if (if_nametoindex(rifname) == 0) {
168 xo_errx(1, "interface %s does not exist",
171 xo_err(1, "if_nametoindex(%s)", rifname);
180 xo_set_version(ARP_XO_VERSION);
181 xo_open_container("arp");
182 xo_open_list("arp-cache");
184 search(0, print_entry);
186 xo_close_list("arp-cache");
187 xo_close_container("arp");
197 if (argc < 2 || argc > 6)
199 if (func == F_REPLACE)
200 (void)delete(argv[0]);
201 rtn = set(argc, argv) ? 1 : 0;
207 search(0, nuke_entry);
211 rtn = delete(argv[0]);
221 if (ifnameindex != NULL)
222 if_freenameindex(ifnameindex);
228 * Process a file to set standard arp entries
235 char line[100], arg[5][50], *args[5], *p;
237 if ((fp = fopen(name, "r")) == NULL)
238 xo_err(1, "cannot open %s", name);
239 args[0] = &arg[0][0];
240 args[1] = &arg[1][0];
241 args[2] = &arg[2][0];
242 args[3] = &arg[3][0];
243 args[4] = &arg[4][0];
245 while(fgets(line, sizeof(line), fp) != NULL) {
246 if ((p = strchr(line, '#')) != NULL)
248 for (p = line; isblank(*p); p++);
249 if (*p == '\n' || *p == '\0')
251 i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1],
252 arg[2], arg[3], arg[4]);
254 xo_warnx("bad line: %s", line);
266 * Given a hostname, fills up a (static) struct sockaddr_in with
267 * the address of the host and returns a pointer to the
270 static struct sockaddr_in *
274 static struct sockaddr_in reply;
276 bzero(&reply, sizeof(reply));
277 reply.sin_len = sizeof(reply);
278 reply.sin_family = AF_INET;
279 reply.sin_addr.s_addr = inet_addr(host);
280 if (reply.sin_addr.s_addr == INADDR_NONE) {
281 if (!(hp = gethostbyname(host))) {
282 xo_warnx("%s: %s", host, hstrerror(h_errno));
285 bcopy((char *)hp->h_addr, (char *)&reply.sin_addr,
286 sizeof reply.sin_addr);
292 * Returns true if the type is a valid one for ARP.
314 * Set an individual arp entry
317 set(int argc, char **argv)
319 struct sockaddr_in *addr;
320 struct sockaddr_in *dst; /* what are we looking for */
321 struct sockaddr_dl *sdl;
322 struct rt_msghdr *rtm;
323 struct ether_addr *ea;
324 char *host = argv[0], *eaddr = argv[1];
325 struct sockaddr_dl sdl_m;
330 bzero(&sdl_m, sizeof(sdl_m));
331 sdl_m.sdl_len = sizeof(sdl_m);
332 sdl_m.sdl_family = AF_LINK;
337 doing_proxy = flags = expire_time = 0;
339 if (strcmp(argv[0], "temp") == 0) {
342 size_t len = sizeof(max_age);
344 clock_gettime(CLOCK_MONOTONIC, &tp);
345 if (sysctlbyname("net.link.ether.inet.max_age",
346 &max_age, &len, NULL, 0) != 0)
347 xo_err(1, "sysctlbyname");
348 expire_time = tp.tv_sec + max_age;
349 } else if (strcmp(argv[0], "pub") == 0) {
350 flags |= RTF_ANNOUNCE;
352 if (argc && strcmp(argv[1], "only") == 0) {
354 * Compatibility: in pre FreeBSD 8 times
355 * the "only" keyword used to mean that
356 * an ARP entry should be announced, but
357 * not installed into routing table.
361 } else if (strcmp(argv[0], "blackhole") == 0) {
362 if (flags & RTF_REJECT) {
363 xo_errx(1, "Choose one of blackhole or reject, "
366 flags |= RTF_BLACKHOLE;
367 } else if (strcmp(argv[0], "reject") == 0) {
368 if (flags & RTF_BLACKHOLE) {
369 xo_errx(1, "Choose one of blackhole or reject, "
374 xo_warnx("Invalid parameter '%s'", argv[0]);
379 ea = (struct ether_addr *)LLADDR(&sdl_m);
380 if (doing_proxy && !strcmp(eaddr, "auto")) {
381 if (!get_ether_addr(dst->sin_addr.s_addr, ea)) {
382 xo_warnx("no interface found for %s",
383 inet_ntoa(dst->sin_addr));
386 sdl_m.sdl_alen = ETHER_ADDR_LEN;
388 struct ether_addr *ea1 = ether_aton(eaddr);
391 xo_warnx("invalid Ethernet address '%s'", eaddr);
395 sdl_m.sdl_alen = ETHER_ADDR_LEN;
400 * In the case a proxy-arp entry is being added for
401 * a remote end point, the RTF_ANNOUNCE flag in the
402 * RTM_GET command is an indication to the kernel
403 * routing code that the interface associated with
404 * the prefix route covering the local end of the
405 * PPP link should be returned, on which ARP applies.
407 rtm = rtmsg(RTM_GET, dst, NULL);
412 addr = (struct sockaddr_in *)(rtm + 1);
413 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
415 if ((sdl->sdl_family != AF_LINK) ||
416 (rtm->rtm_flags & RTF_GATEWAY) ||
417 !valid_type(sdl->sdl_type)) {
418 xo_warnx("cannot intuit interface index and type for %s", host);
421 sdl_m.sdl_type = sdl->sdl_type;
422 sdl_m.sdl_index = sdl->sdl_index;
423 return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL);
427 * Display an individual arp entry
432 struct sockaddr_in *addr;
435 addr = getaddr(host);
439 xo_set_version(ARP_XO_VERSION);
440 xo_open_container("arp");
441 xo_open_list("arp-cache");
443 found = search(addr->sin_addr.s_addr, print_entry);
446 xo_emit("{d:hostname/%s} ({d:ip-address/%s}) -- no entry",
447 host, inet_ntoa(addr->sin_addr));
449 xo_emit(" on {d:interface/%s}", rifname);
453 xo_close_list("arp-cache");
454 xo_close_container("arp");
461 * Delete an arp entry
466 struct sockaddr_in *addr, *dst;
467 struct rt_msghdr *rtm;
468 struct sockaddr_dl *sdl;
475 * Perform a regular entry delete first.
477 flags &= ~RTF_ANNOUNCE;
479 for (;;) { /* try twice */
480 rtm = rtmsg(RTM_GET, dst, NULL);
485 addr = (struct sockaddr_in *)(rtm + 1);
486 sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
489 * With the new L2/L3 restructure, the route
490 * returned is a prefix route. The important
491 * piece of information from the previous
492 * RTM_GET is the interface index. In the
493 * case of ECMP, the kernel will traverse
494 * the route group for the given entry.
496 if (sdl->sdl_family == AF_LINK &&
497 !(rtm->rtm_flags & RTF_GATEWAY) &&
498 valid_type(sdl->sdl_type) ) {
499 addr->sin_addr.s_addr = dst->sin_addr.s_addr;
504 * Regular entry delete failed, now check if there
505 * is a proxy-arp entry to remove.
507 if (flags & RTF_ANNOUNCE) {
508 xo_warnx("delete: cannot locate %s", host);
512 flags |= RTF_ANNOUNCE;
514 rtm->rtm_flags |= RTF_LLDATA;
515 if (rtmsg(RTM_DELETE, dst, NULL) != NULL) {
516 printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr));
524 * Search the arp table and do some action on matching entries
527 search(u_long addr, action_fn *action)
531 char *lim, *buf, *next;
532 struct rt_msghdr *rtm;
533 struct sockaddr_in *sin2;
534 struct sockaddr_dl *sdl;
535 char ifname[IF_NAMESIZE];
536 int st, found_entry = 0;
542 mib[4] = NET_RT_FLAGS;
548 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
549 xo_err(1, "route-sysctl-estimate");
550 if (needed == 0) /* empty table */
554 buf = reallocf(buf, needed);
556 xo_errx(1, "could not reallocate memory");
557 st = sysctl(mib, 6, buf, &needed, NULL, 0);
558 if (st == 0 || errno != ENOMEM)
560 needed += needed / 8;
563 xo_err(1, "actual retrieval of routing table");
565 for (next = buf; next < lim; next += rtm->rtm_msglen) {
566 rtm = (struct rt_msghdr *)next;
567 sin2 = (struct sockaddr_in *)(rtm + 1);
568 sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
569 if (rifname && if_indextoname(sdl->sdl_index, ifname) &&
570 strcmp(ifname, rifname))
573 if (addr != sin2->sin_addr.s_addr)
577 (*action)(sdl, sin2, rtm);
580 return (found_entry);
584 * Display an arp entry
588 print_entry(struct sockaddr_dl *sdl,
589 struct sockaddr_in *addr, struct rt_msghdr *rtm)
593 struct iso88025_sockaddr_dl_data *trld;
594 struct if_nameindex *p;
597 if (ifnameindex == NULL)
598 if ((ifnameindex = if_nameindex()) == NULL)
599 xo_err(1, "cannot retrieve interface names");
601 xo_open_instance("arp-cache");
604 hp = gethostbyaddr((caddr_t)&(addr->sin_addr),
605 sizeof addr->sin_addr, AF_INET);
612 if (h_errno == TRY_AGAIN)
615 xo_emit("{:hostname/%s} ({:ip-address/%s}) at ", host,
616 inet_ntoa(addr->sin_addr));
618 if ((sdl->sdl_type == IFT_ETHER ||
619 sdl->sdl_type == IFT_L2VLAN ||
620 sdl->sdl_type == IFT_BRIDGE) &&
621 sdl->sdl_alen == ETHER_ADDR_LEN)
622 xo_emit("{:mac-address/%s}",
623 ether_ntoa((struct ether_addr *)LLADDR(sdl)));
625 int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0;
627 xo_emit("{:mac-address/%s}", link_ntoa(sdl) + n);
630 xo_emit("{d:/(incomplete)}{en:incomplete/true}");
632 for (p = ifnameindex; p && ifnameindex->if_index &&
633 ifnameindex->if_name; p++) {
634 if (p->if_index == sdl->sdl_index) {
635 xo_emit(" on {:interface/%s}", p->if_name);
640 if (rtm->rtm_rmx.rmx_expire == 0)
641 xo_emit("{d:/ permanent}{en:permanent/true}");
643 static struct timespec tp;
645 clock_gettime(CLOCK_MONOTONIC, &tp);
646 if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0)
647 xo_emit(" expires in {:expires/%d} seconds",
650 xo_emit("{d:/ expired}{en:expired/true}");
653 if (rtm->rtm_flags & RTF_ANNOUNCE)
654 xo_emit("{d:/ published}{en:published/true}");
656 switch(sdl->sdl_type) {
658 xo_emit(" [{:type/ethernet}]");
661 xo_emit(" [{:type/token-ring}]");
662 trld = SDL_ISO88025(sdl);
663 if (trld->trld_rcf != 0) {
664 xo_emit(" rt=%x", ntohs(trld->trld_rcf));
666 seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2);
668 xo_emit(":%x", ntohs(*(trld->trld_route[seg])));
672 xo_emit(" [{:type/fddi}]");
675 xo_emit(" [{:type/atm}]");
678 xo_emit(" [{:type/vlan}]");
681 xo_emit(" [{:type/firewire}]");
684 xo_emit(" [{:type/bridge}]");
687 xo_emit(" [{:type/infiniband}]");
695 xo_close_instance("arp-cache");
702 nuke_entry(struct sockaddr_dl *sdl __unused,
703 struct sockaddr_in *addr, struct rt_msghdr *rtm)
707 if (rtm->rtm_flags & RTF_PINNED)
710 snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
717 fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
718 "usage: arp [-n] [-i interface] hostname",
719 " arp [-n] [-i interface] -a",
720 " arp -d hostname [pub]",
721 " arp -d [-i interface] -a",
722 " arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]",
723 " arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]",
728 static struct rt_msghdr *
729 rtmsg(int cmd, struct sockaddr_in *dst, struct sockaddr_dl *sdl)
734 struct sockaddr_in so_mask, *som = &so_mask;
739 struct rt_msghdr m_rtm;
743 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
744 char *cp = m_rtmsg.m_space;
746 if (s < 0) { /* first time: open socket, get pid */
747 s = socket(PF_ROUTE, SOCK_RAW, 0);
752 bzero(&so_mask, sizeof(so_mask));
754 so_mask.sin_addr.s_addr = 0xffffffff;
758 * XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer
761 if (cmd == RTM_DELETE)
763 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
764 rtm->rtm_flags = flags;
765 rtm->rtm_version = RTM_VERSION;
769 xo_errx(1, "internal wrong cmd");
771 rtm->rtm_addrs |= RTA_GATEWAY;
772 rtm->rtm_rmx.rmx_expire = expire_time;
773 rtm->rtm_inits = RTV_EXPIRE;
774 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
776 rtm->rtm_addrs |= RTA_NETMASK;
777 rtm->rtm_flags &= ~RTF_HOST;
781 rtm->rtm_addrs |= RTA_DST;
783 #define NEXTADDR(w, s) \
785 if ((s) != NULL && rtm->rtm_addrs & (w)) { \
786 bcopy((s), cp, sizeof(*(s))); \
791 NEXTADDR(RTA_DST, dst);
792 NEXTADDR(RTA_GATEWAY, sdl);
793 NEXTADDR(RTA_NETMASK, som);
795 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
798 rtm->rtm_seq = ++seq;
800 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
801 if (errno != ESRCH || cmd != RTM_DELETE) {
802 xo_warn("writing to routing socket");
807 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
808 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq ||
809 rtm->rtm_pid != pid));
811 xo_warn("read from routing socket");
816 * get_ether_addr - get the hardware address of an interface on the
817 * the same subnet as ipaddr.
822 get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr)
824 struct ifreq *ifr, *ifend, *ifp;
826 struct sockaddr_dl *dla;
829 struct ifreq ifs[MAX_IFS];
833 sock = socket(AF_INET, SOCK_DGRAM, 0);
837 ifc.ifc_len = sizeof(ifs);
839 if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
840 xo_warnx("ioctl(SIOCGIFCONF)");
845 ((struct ifreq *)((char *)&(i)->ifr_addr \
846 + MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) )
849 * Scan through looking for an interface with an Internet
850 * address on the same subnet as `ipaddr'.
852 ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len);
853 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) {
854 if (ifr->ifr_addr.sa_family != AF_INET)
856 strncpy(ifreq.ifr_name, ifr->ifr_name,
857 sizeof(ifreq.ifr_name));
858 ifreq.ifr_addr = ifr->ifr_addr;
860 * Check that the interface is up,
861 * and not point-to-point or loopback.
863 if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
865 if ((ifreq.ifr_flags &
866 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
867 IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST))
869 /* Get its netmask and check that it's on the right subnet. */
870 if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
872 mask = ((struct sockaddr_in *)
873 &ifreq.ifr_addr)->sin_addr.s_addr;
874 ina = ((struct sockaddr_in *)
875 &ifr->ifr_addr)->sin_addr.s_addr;
876 if ((ipaddr & mask) == (ina & mask))
877 break; /* ok, we got it! */
884 * Now scan through again looking for a link-level address
885 * for this interface.
888 for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr))
889 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 &&
890 ifr->ifr_addr.sa_family == AF_LINK)
895 * Found the link-level address - copy it out
897 dla = (struct sockaddr_dl *) &ifr->ifr_addr;
898 memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
899 printf("using interface %s for proxy with address %s\n", ifp->ifr_name,
901 retval = dla->sdl_alen;