/* $NetBSD: arp.c,v 1.42 2006/01/31 17:47:04 christos Exp $ */ /* * Copyright (c) 1984, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Sun Microsystems, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1984, 1993\n\ The Regents of the University of California. All rights reserved.\n"); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; #else __RCSID("$NetBSD: arp.c,v 1.42 2006/01/31 17:47:04 christos Exp $"); #endif #endif /* not lint */ /* * arp - display, set, and delete arp table entries */ /* Roundup the same way rt_xaddrs does */ #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int delete(const char *, const char *); void dump(u_long); void delete_all(void); void sdl_print(const struct sockaddr_dl *); int getifname(u_int16_t, char *, size_t); int atosdl(const char *s, struct sockaddr_dl *sdl); int file(char *); void get(const char *); int getinetaddr(const char *, struct in_addr *); void getsocket(void); int rtmsg(int); int set(int, char **); void usage(void); static int pid; static int aflag, nflag, vflag; static int s = -1; static struct ifaddrs* ifaddrs = NULL; int main(int argc, char **argv) { int ch; int op = 0; setprogname(argv[0]); pid = getpid(); while ((ch = getopt(argc, argv, "andsfv")) != -1) switch((char)ch) { case 'a': aflag = 1; break; case 'd': case 's': case 'f': if (op) usage(); op = ch; break; case 'n': nflag = 1; break; case 'v': vflag = 1; break; default: usage(); } argc -= optind; argv += optind; if (!op && aflag) op = 'a'; switch((char)op) { case 'a': dump(0); break; case 'd': if (aflag && argc == 0) delete_all(); else { if (aflag || argc < 1 || argc > 2) usage(); (void)delete(argv[0], argv[1]); } break; case 's': if (argc < 2 || argc > 5) usage(); return (set(argc, argv) ? 1 : 0); case 'f': if (argc != 1) usage(); return (file(argv[0])); default: if (argc != 1) usage(); get(argv[0]); break; } return (0); } /* * Process a file to set standard arp entries */ int file(char *name) { char line[100], arg[5][50], *args[5]; int i, retval; FILE *fp; if ((fp = fopen(name, "r")) == NULL) err(1, "cannot open %s", name); args[0] = &arg[0][0]; args[1] = &arg[1][0]; args[2] = &arg[2][0]; args[3] = &arg[3][0]; args[4] = &arg[4][0]; retval = 0; while (fgets(line, 100, fp) != NULL) { i = sscanf(line, "%49s %49s %49s %49s %49s", arg[0], arg[1], arg[2], arg[3], arg[4]); if (i < 2) { warnx("bad line: %s", line); retval = 1; continue; } if (set(i, args)) retval = 1; } fclose(fp); return (retval); } void getsocket(void) { if (s >= 0) return; s = socket(PF_ROUTE, SOCK_RAW, 0); if (s < 0) err(1, "socket"); } struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; int expire_time, flags, export_only, doing_proxy, found_entry; struct { struct rt_msghdr m_rtm; char m_space[512]; } m_rtmsg; /* * Set an individual arp entry */ int set(int argc, char **argv) { struct sockaddr_inarp *sina; struct sockaddr_dl *sdl; struct rt_msghdr *rtm; char *host = argv[0], *eaddr; int rval; sina = &sin_m; rtm = &(m_rtmsg.m_rtm); eaddr = argv[1]; getsocket(); argc -= 2; argv += 2; sdl_m = blank_sdl; /* struct copy */ sin_m = blank_sin; /* struct copy */ if (getinetaddr(host, &sina->sin_addr) == -1) return (1); if (atosdl(eaddr, &sdl_m)) warnx("invalid link-level address '%s'", eaddr); doing_proxy = flags = export_only = expire_time = 0; while (argc-- > 0) { if (strncmp(argv[0], "temp", 4) == 0) { struct timeval timev; (void)gettimeofday(&timev, 0); expire_time = timev.tv_sec + 20 * 60; } else if (strncmp(argv[0], "pub", 3) == 0) { flags |= RTF_ANNOUNCE; doing_proxy = SIN_PROXY; } else if (strncmp(argv[0], "trail", 5) == 0) { (void)printf( "%s: Sending trailers is no longer supported\n", host); } argv++; } tryagain: if (rtmsg(RTM_GET) < 0) { warn("%s", host); return (1); } sina = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *)(ROUNDUP(sina->sin_len) + (char *)sina); if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { if (sdl->sdl_family == AF_LINK && (rtm->rtm_flags & RTF_LLINFO) && !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: goto overwrite; } if (doing_proxy == 0) { (void)printf("set: can only proxy for %s\n", host); return (1); } if (sin_m.sin_other & SIN_PROXY) { (void)printf( "set: proxy entry exists for non 802 device\n"); return (1); } sin_m.sin_other = SIN_PROXY; export_only = 1; goto tryagain; } overwrite: if (sdl->sdl_family != AF_LINK) { (void)printf("cannot intuit interface index and type for %s\n", host); return (1); } sdl_m.sdl_type = sdl->sdl_type; sdl_m.sdl_index = sdl->sdl_index; rval = rtmsg(RTM_ADD); if (vflag) (void)printf("%s (%s) added\n", host, eaddr); return (rval); } /* * Display an individual arp entry */ void get(const char *host) { struct sockaddr_inarp *sina; sina = &sin_m; sin_m = blank_sin; /* struct copy */ if (getinetaddr(host, &sina->sin_addr) == -1) exit(1); dump(sina->sin_addr.s_addr); if (found_entry == 0) { (void)printf("%s (%s) -- no entry\n", host, inet_ntoa(sina->sin_addr)); exit(1); } } /* * Delete an arp entry */ int delete(const char *host, const char *info) { struct sockaddr_inarp *sina; struct rt_msghdr *rtm; struct sockaddr_dl *sdl; sina = &sin_m; rtm = &m_rtmsg.m_rtm; if (info && strncmp(info, "pub", 3) == 0) export_only = 1; getsocket(); sin_m = blank_sin; /* struct copy */ if (getinetaddr(host, &sina->sin_addr) == -1) return (1); tryagain: if (rtmsg(RTM_GET) < 0) { warn("%s", host); return (1); } sina = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *)(ROUNDUP(sina->sin_len) + (char *)sina); if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { if (sdl->sdl_family == AF_LINK && (rtm->rtm_flags & RTF_LLINFO) && !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: goto delete; } } if (sin_m.sin_other & SIN_PROXY) { warnx("delete: can't locate %s", host); return (1); } else { sin_m.sin_other = SIN_PROXY; goto tryagain; } delete: if (sdl->sdl_family != AF_LINK) { (void)printf("cannot locate %s\n", host); return (1); } if (rtmsg(RTM_DELETE)) return (1); if (vflag) (void)printf("%s (%s) deleted\n", host, inet_ntoa(sina->sin_addr)); return (0); } /* * Dump the entire arp table */ void dump(u_long addr) { int mib[6]; size_t needed; char ifname[IFNAMSIZ]; char *lim, *buf, *next; const char *host; struct rt_msghdr *rtm; struct sockaddr_inarp *sina; struct sockaddr_dl *sdl; struct hostent *hp; mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = AF_INET; mib[4] = NET_RT_FLAGS; mib[5] = RTF_LLINFO; if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) err(1, "route-sysctl-estimate"); if (needed == 0) return; if ((buf = malloc(needed)) == NULL) err(1, "malloc"); if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) err(1, "actual retrieval of routing table"); lim = buf + needed; for (next = buf; next < lim; next += rtm->rtm_msglen) { rtm = (struct rt_msghdr *)next; sina = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *) (ROUNDUP(sina->sin_len) + (char *)sina); if (addr) { if (addr != sina->sin_addr.s_addr) continue; found_entry = 1; } if (nflag == 0) hp = gethostbyaddr((caddr_t)&(sina->sin_addr), sizeof sina->sin_addr, AF_INET); else hp = NULL; host = hp ? hp->h_name : "?"; (void)printf("%s (%s) at ", host, inet_ntoa(sina->sin_addr)); if (sdl->sdl_alen) sdl_print(sdl); else (void)printf("(incomplete)"); if (sdl->sdl_index) { if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0) printf(" on %s", ifname); } if (rtm->rtm_rmx.rmx_expire == 0) (void)printf(" permanent"); if (sina->sin_other & SIN_PROXY) (void)printf(" published (proxy only)"); if (rtm->rtm_addrs & RTA_NETMASK) { sina = (struct sockaddr_inarp *) (ROUNDUP(sdl->sdl_len) + (char *)sdl); if (sina->sin_addr.s_addr == 0xffffffff) (void)printf(" published"); if (sina->sin_len != 8) (void)printf("(weird)"); } (void)printf("\n"); } free(buf); } /* * Delete the entire arp table */ void delete_all(void) { int mib[6]; size_t needed; char addr[sizeof("000.000.000.000\0")]; char *lim, *buf, *next; struct rt_msghdr *rtm; struct sockaddr_inarp *sina; struct sockaddr_dl *sdl; mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = AF_INET; mib[4] = NET_RT_FLAGS; mib[5] = RTF_LLINFO; if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) err(1, "route-sysctl-estimate"); if (needed == 0) return; if ((buf = malloc(needed)) == NULL) err(1, "malloc"); if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) err(1, "actual retrieval of routing table"); lim = buf + needed; for (next = buf; next < lim; next += rtm->rtm_msglen) { rtm = (struct rt_msghdr *)next; sina = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *) (ROUNDUP(sina->sin_len) + (char *)sina); snprintf(addr, sizeof(addr), "%s", inet_ntoa(sina->sin_addr)); delete(addr, NULL); } free(buf); } void sdl_print(const struct sockaddr_dl *sdl) { char hbuf[NI_MAXHOST]; if (getnameinfo((const struct sockaddr *)sdl, sdl->sdl_len, hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) printf(""); else printf("%s", hbuf); } int atosdl(const char *ss, struct sockaddr_dl *sdl) { int i; long b; caddr_t endp; caddr_t p; char *t, *r; p = LLADDR(sdl); endp = ((caddr_t)sdl) + sdl->sdl_len; i = 0; b = strtol(ss, &t, 16); if (t == ss) return 1; *p++ = b; ++i; while ((p < endp) && (*t++ == ':')) { b = strtol(t, &r, 16); if (r == t) break; *p++ = b; ++i; t = r; } sdl->sdl_alen = i; return 0; } void usage(void) { const char *progname; progname = getprogname(); (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); (void)fprintf(stderr, "usage: %s [-nv] -a\n", progname); (void)fprintf(stderr, "usage: %s [-v] -d [-a|hostname [pub]]\n", progname); (void)fprintf(stderr, "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); (void)fprintf(stderr, "usage: %s -f filename\n", progname); exit(1); } int rtmsg(int cmd) { static int seq; int rlen; struct rt_msghdr *rtm; char *cp; int l; rtm = &m_rtmsg.m_rtm; cp = m_rtmsg.m_space; errno = 0; if (cmd == RTM_DELETE) goto doit; (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); rtm->rtm_flags = flags; rtm->rtm_version = RTM_VERSION; switch (cmd) { default: errx(1, "internal wrong cmd"); /*NOTREACHED*/ case RTM_ADD: rtm->rtm_addrs |= RTA_GATEWAY; rtm->rtm_rmx.rmx_expire = expire_time; rtm->rtm_inits = RTV_EXPIRE; rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); sin_m.sin_other = 0; if (doing_proxy) { if (export_only) sin_m.sin_other = SIN_PROXY; else { rtm->rtm_addrs |= RTA_NETMASK; rtm->rtm_flags &= ~RTF_HOST; } } /* FALLTHROUGH */ case RTM_GET: rtm->rtm_addrs |= RTA_DST; } #define NEXTADDR(w, s) \ if (rtm->rtm_addrs & (w)) { \ (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ } NEXTADDR(RTA_DST, sin_m); NEXTADDR(RTA_GATEWAY, sdl_m); NEXTADDR(RTA_NETMASK, so_mask); rtm->rtm_msglen = cp - (char *)&m_rtmsg; doit: l = rtm->rtm_msglen; rtm->rtm_seq = ++seq; rtm->rtm_type = cmd; if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { if (errno != ESRCH || cmd != RTM_DELETE) { warn("writing to routing socket"); return (-1); } } do { l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); if (l < 0) warn("read from routing socket"); return (0); } int getinetaddr(const char *host, struct in_addr *inap) { struct hostent *hp; if (inet_aton(host, inap) == 1) return (0); if ((hp = gethostbyname(host)) == NULL) { warnx("%s: %s", host, hstrerror(h_errno)); return (-1); } (void)memcpy(inap, hp->h_addr, sizeof(*inap)); return (0); } int getifname(u_int16_t ifindex, char *ifname, size_t l) { int i; struct ifaddrs *addr; const struct sockaddr_dl *sdl = NULL; if (ifaddrs == NULL) { i = getifaddrs(&ifaddrs); if (i != 0) err(1, "getifaddrs"); } for (addr = ifaddrs; addr; addr = addr->ifa_next) { if (addr->ifa_addr == NULL || addr->ifa_addr->sa_family != AF_LINK) continue; sdl = (const struct sockaddr_dl *) addr->ifa_addr; if (sdl && sdl->sdl_index == ifindex) { (void) strlcpy(ifname, addr->ifa_name, l); return 0; } } return -1; }