/* $NetBSD: arp.c,v 1.68 2020/09/15 11:14:16 roy 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\ The Regents of the University of California. All rights reserved."); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; #else __RCSID("$NetBSD: arp.c,v 1.68 2020/09/15 11:14:16 roy Exp $"); #endif #endif /* not lint */ /* * arp - display, set, and delete arp table entries */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "prog_ops.h" static int is_llinfo(const struct sockaddr_dl *, int); static int delete_one(struct rt_msghdr *); static void dump(uint32_t); static void delete(const char *, const char *); static void sdl_print(const struct sockaddr_dl *); static int getifname(u_int16_t, char *, size_t); static int atosdl(const char *, struct sockaddr_dl *); static int file(const char *); static void get(const char *); static int getinetaddr(const char *, struct in_addr *); static int getsocket(void); static int getetheraddr(struct in_addr, struct sockaddr_dl *); static struct rt_msghdr * rtmsg(const int, const int, struct rt_msghdr *, const struct sockaddr_inarp *, const struct sockaddr_dl *); static struct in_nbrinfo * getnbrinfo(const char *, struct in_addr *); static const char * sec2str(time_t); static int set(int, char **); static void usage(void) __dead; static int aflag, nflag, vflag; static struct sockaddr_in so_mask = { .sin_len = 8, .sin_addr = { .s_addr = 0xffffffff } }; static struct sockaddr_inarp blank_sin = { .sin_len = sizeof(blank_sin), .sin_family = AF_INET }; static struct sockaddr_dl blank_sdl = { .sdl_len = sizeof(blank_sdl), .sdl_family = AF_LINK }; static int expire_time, flags, export_only, doing_proxy, found_entry; int main(int argc, char **argv) { int ch; int op = 0; setprogname(argv[0]); 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'; if (prog_init && prog_init() == -1) err(1, "init failed"); switch((char)op) { case 'a': dump(0); break; case 'd': if (aflag && argc == 0) delete(NULL, NULL); else { if (aflag || argc < 1 || argc > 2) usage(); delete(argv[0], argv[1]); } break; case 's': if (argc < 2 || argc > 7) 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 */ static int file(const char *name) { char *line, *argv[5]; int i, retval; FILE *fp; if (!strcmp(name, "-")) { fp = stdin; } else { fp = fopen(name, "r"); if (fp == NULL) { err(1, "Cannot open %s", name); } } retval = 0; for (; (line = fparseln(fp, NULL, NULL, NULL, 0)) != NULL; free(line)) { char **ap, *inputstring; inputstring = line; for (ap = argv; ap < &argv[sizeof(argv) / sizeof(argv[0])] && (*ap = stresep(&inputstring, " \t", '\\')) != NULL;) { if (**ap != '\0') ap++; } i = ap - argv; if (i < 2) { warnx("bad line: %s", line); retval = 1; continue; } if (set(i, argv)) retval = 1; } if (fp != stdin) (void)fclose(fp); return retval; } static int getsocket(void) { int s; s = prog_socket(PF_ROUTE, SOCK_RAW, 0); if (s < 0) err(1, "socket"); return s; } static int getlink(const char *name, struct sockaddr_dl *sdl) { struct ifaddrs *ifap, *ifa; if (getifaddrs(&ifap) != 0) { warn("getifaddrs"); return 0; } for (ifa = ifap; ifa; ifa = ifa->ifa_next) { if (ifa->ifa_addr->sa_family != AF_LINK) continue; if (strcmp(ifa->ifa_name, name) != 0) continue; memcpy(sdl, ifa->ifa_addr, sizeof(*sdl)); freeifaddrs(ifap); return 1; } freeifaddrs(ifap); return 0; } /* * Set an individual arp entry */ static int set(int argc, char **argv) { struct sockaddr_inarp *sina; struct sockaddr_dl *sdl = NULL; struct rt_msghdr *rtm; char *host = argv[0], *eaddr; struct sockaddr_inarp sin_m = blank_sin; /* struct copy */ struct sockaddr_dl sdl_m = blank_sdl; /* struct copy */ int s; eaddr = argv[1]; s = getsocket(); argc -= 2; argv += 2; if (getinetaddr(host, &sin_m.sin_addr) == -1) { prog_close(s); return (1); } if (strcmp(eaddr, "auto") != 0 && atosdl(eaddr, &sdl_m)) warnx("invalid link-level address '%s'", eaddr); doing_proxy = flags = export_only = expire_time = 0; for (; argc-- > 0; argv++) { 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 = 1; if (argc && strncmp(argv[1], "pro", 3) == 0) { export_only = 1; argc--; argv++; } } else if (strncmp(argv[0], "trail", 5) == 0) { warnx("%s: Sending trailers is no longer supported", host); } else if (strcmp(argv[0], "ifscope") == 0) { if (argc == 0) { warnx("missing interface for ifscope"); continue; } argc--; argv++; if (!getlink(argv[0], &sdl_m)) warnx("cannot get link address for %s", argv[0]); } } if (doing_proxy && strcmp(eaddr, "auto") == 0) { if (getetheraddr(sin_m.sin_addr, &sdl_m) == -1) { prog_close(s); return 1; } } tryagain: rtm = rtmsg(s, RTM_GET, NULL, &sin_m, &sdl_m); if (rtm == NULL) { warn("%s", host); prog_close(s); return (1); } sina = (struct sockaddr_inarp *)(void *)(rtm + 1); sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) + (char *)(void *)sina); if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { if (is_llinfo(sdl, rtm->rtm_flags)) goto overwrite; if (doing_proxy == 0) { warnx("set: can only proxy for %s", host); prog_close(s); return (1); } if (sin_m.sin_other & SIN_PROXY) { warnx("set: proxy entry exists for non 802 device"); prog_close(s); return (1); } sin_m.sin_other = SIN_PROXY; export_only = 1; goto tryagain; } overwrite: if (sdl->sdl_family != AF_LINK) { warnx("cannot intuit interface index and type for %s", host); prog_close(s); return (1); } sdl_m.sdl_type = sdl->sdl_type; sdl_m.sdl_index = sdl->sdl_index; sin_m.sin_other = 0; if (doing_proxy && export_only) sin_m.sin_other = SIN_PROXY; rtm = rtmsg(s, RTM_ADD, NULL, &sin_m, &sdl_m); if (vflag) (void)printf("%s (%s) added\n", host, eaddr); prog_close(s); return (rtm == NULL) ? 1 : 0; } /* * Display an individual arp entry */ static void get(const char *host) { struct sockaddr_inarp sin = blank_sin; /* struct copy */ if (getinetaddr(host, &sin.sin_addr) == -1) exit(1); dump(sin.sin_addr.s_addr); if (found_entry == 0) errx(1, "%s (%s) -- no entry", host, inet_ntoa(sin.sin_addr)); } static int is_llinfo(const struct sockaddr_dl *sdl, int rtflags) { if (sdl->sdl_family != AF_LINK || (rtflags & (RTF_LLDATA|RTF_GATEWAY)) != RTF_LLDATA) return 0; switch (sdl->sdl_type) { case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: return 1; default: return 0; } } /* * Delete an arp entry */ int delete_one(struct rt_msghdr *rtm) { struct sockaddr_inarp *sina; struct sockaddr_dl *sdl; int s; s = getsocket(); sina = (struct sockaddr_inarp *)(void *)(rtm + 1); sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) + (char *)(void *)sina); if (sdl->sdl_family != AF_LINK) { prog_close(s); return (1); } rtm = rtmsg(s, RTM_DELETE, rtm, sina, sdl); prog_close(s); if (rtm == NULL) return (1); return (0); } /* * Dump the entire arp table */ void dump(uint32_t 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; struct timeval tim; struct in_nbrinfo *nbi; mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = AF_INET; mib[4] = NET_RT_FLAGS; mib[5] = 0; if (prog_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 (prog_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 *)(void *)next; sina = (struct sockaddr_inarp *)(void *)(rtm + 1); sdl = (struct sockaddr_dl *)(void *) (RT_ROUNDUP(sina->sin_len) + (char *)(void *)sina); if (addr) { if (addr != sina->sin_addr.s_addr) continue; found_entry = 1; } if (nflag == 0) hp = gethostbyaddr((const char *)(void *) &(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) (void)printf(" on %s", ifname); } if (sina->sin_other & SIN_PROXY) (void)printf(" published (proxy only)"); if (rtm->rtm_addrs & RTA_NETMASK) { sina = (struct sockaddr_inarp *)(void *) (RT_ROUNDUP(sdl->sdl_len) + (char *)(void *)sdl); if (sina->sin_addr.s_addr == 0xffffffff) (void)printf(" published"); if (sina->sin_len != 8) (void)printf("(weird)"); } if (sdl->sdl_index == 0) goto done; (void)gettimeofday(&tim, 0); nbi = getnbrinfo(ifname, &sina->sin_addr); if (nbi != NULL) { if (nbi->expire > tim.tv_sec) { (void)printf(" %s", sec2str(nbi->expire - tim.tv_sec)); } else if (nbi->expire == 0) (void)printf(" %s", "permanent"); else (void)printf(" %s", "expired"); switch (nbi->state) { case ND_LLINFO_NOSTATE: (void)printf(" N"); break; case ND_LLINFO_WAITDELETE: (void)printf(" W"); break; case ND_LLINFO_INCOMPLETE: (void)printf(" I"); break; case ND_LLINFO_REACHABLE: (void)printf(" R"); break; case ND_LLINFO_STALE: (void)printf(" S"); break; case ND_LLINFO_DELAY: (void)printf(" D"); break; case ND_LLINFO_PROBE: (void)printf(" P"); break; case ND_LLINFO_UNREACHABLE: (void)printf(" U"); break; default: (void)printf(" ?"); break; } } done: (void)printf("\n"); } free(buf); } /* * Delete the entire arp table */ void delete(const char *host, const char *info) { int mib[6]; char addr[sizeof("000.000.000.000\0")]; size_t needed; char *lim, *buf, *next; struct rt_msghdr *rtm; struct sockaddr_inarp *sina; struct sockaddr_inarp sin_m = blank_sin; /* struct copy */ bool found = false; if (host != NULL) { int ret = getinetaddr(host, &sin_m.sin_addr); if (ret == -1) return; } if (info && strncmp(info, "pro", 3) == 0) sin_m.sin_other = SIN_PROXY; retry: mib[0] = CTL_NET; mib[1] = PF_ROUTE; mib[2] = 0; mib[3] = AF_INET; mib[4] = NET_RT_FLAGS; mib[5] = RTF_LLDATA; if (prog_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 (prog_sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { free(buf); if (errno == ENOBUFS) goto retry; err(1, "actual retrieval of routing table"); } lim = buf + needed; for (next = buf; next < lim; next += rtm->rtm_msglen) { int ret; rtm = (struct rt_msghdr *)(void *)next; sina = (struct sockaddr_inarp *)(void *)(rtm + 1); if (host != NULL && sina->sin_addr.s_addr != sin_m.sin_addr.s_addr) continue; found = true; ret = delete_one(rtm); if (vflag && ret == 0) { snprintf(addr, sizeof(addr), "%s", inet_ntoa(sina->sin_addr)); (void)printf("%s (%s) deleted\n", host != NULL ? host : addr, addr); } } if (host != NULL && !found) warnx("delete: can't locate %s", host); free(buf); } void sdl_print(const struct sockaddr_dl *sdl) { char hbuf[NI_MAXHOST]; if (getnameinfo((const struct sockaddr *)(const void *)sdl, (socklen_t)sdl->sdl_len, hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) (void)printf(""); else (void)printf("%s", hbuf); } static int atosdl(const char *ss, struct sockaddr_dl *sdl) { int i; unsigned long b; char *endp; char *p; char *t, *r; p = LLADDR(sdl); endp = ((char *)(void *)sdl) + sdl->sdl_len; i = 0; b = strtoul(ss, &t, 16); if (b > 255 || t == ss) return 1; *p++ = (char)b; ++i; while ((p < endp) && (*t++ == ':')) { b = strtoul(t, &r, 16); if (b > 255 || r == t) break; *p++ = (char)b; ++i; t = r; } sdl->sdl_alen = i; return 0; } static void usage(void) { const char *progname; progname = getprogname(); (void)fprintf(stderr, "Usage: %s [-n] hostname\n", progname); (void)fprintf(stderr, " %s [-nv] -a\n", progname); (void)fprintf(stderr, " %s [-v] -d [-a|hostname [proxy]]\n", progname); (void)fprintf(stderr, " %s -s hostname ether_addr [temp] [pub [proxy]]\n", progname); (void)fprintf(stderr, " %s -f filename\n", progname); exit(1); } static struct rt_msghdr * rtmsg(const int s, const int cmd, struct rt_msghdr *_rtm, const struct sockaddr_inarp *sin, const struct sockaddr_dl *sdl) { static int seq; struct rt_msghdr *rtm = _rtm; char *cp; int l; static struct { struct rt_msghdr m_rtm; char m_space[512]; } m_rtmsg; pid_t pid; errno = 0; if (rtm != NULL) { memcpy(&m_rtmsg, rtm, rtm->rtm_msglen); rtm = &m_rtmsg.m_rtm; goto doit; } (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); rtm = &m_rtmsg.m_rtm; cp = m_rtmsg.m_space; 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 | RTF_LLDATA); if (doing_proxy) { if (!export_only) { rtm->rtm_addrs |= RTA_NETMASK; rtm->rtm_flags &= ~RTF_HOST; } } rtm->rtm_addrs |= RTA_DST; break; case RTM_GET: rtm->rtm_flags |= RTF_LLDATA; rtm->rtm_addrs |= RTA_DST | RTA_GATEWAY; } #define NEXTADDR(w, s) \ if (rtm->rtm_addrs & (w)) { \ (void)memcpy(cp, &s, \ (size_t)((const struct sockaddr *)&s)->sa_len); \ RT_ADVANCE(cp, ((const struct sockaddr *)&s)); \ } NEXTADDR(RTA_DST, *sin); NEXTADDR(RTA_GATEWAY, *sdl); NEXTADDR(RTA_NETMASK, so_mask); rtm->rtm_msglen = cp - (char *)(void *)&m_rtmsg; doit: l = rtm->rtm_msglen; rtm->rtm_seq = ++seq; rtm->rtm_type = cmd; if (prog_write(s, &m_rtmsg, (size_t)l) < 0) { if (errno != ESRCH || cmd != RTM_DELETE) { warn("writing to routing socket"); return NULL; } } pid = prog_getpid(); do { l = prog_read(s, &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 rtm; } static 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); } static int getifname(u_int16_t ifindex, char *ifname, size_t l) { int i; struct ifaddrs *addr; const struct sockaddr_dl *sdl; static struct ifaddrs* ifaddrs = 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 *)(void *)addr->ifa_addr; if (sdl && sdl->sdl_index == ifindex) { (void) strlcpy(ifname, addr->ifa_name, l); return 0; } } return -1; } static int getetheraddr(struct in_addr ipaddr, struct sockaddr_dl *sdl) { struct ifaddrs *ifaddrs, *addr; in_addr_t ina, mask; char ifname[IFNAMSIZ]; if (getifaddrs(&ifaddrs) != 0) { warn("getifaddrs"); return -1; } for (addr = ifaddrs; addr; addr = addr->ifa_next) { if (addr->ifa_addr == NULL || addr->ifa_addr->sa_family != AF_INET) continue; if ((addr->ifa_flags & (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) continue; mask = ((struct sockaddr_in *)(void *)addr->ifa_netmask)->sin_addr.s_addr; ina = ((struct sockaddr_in *)(void *)addr->ifa_addr)->sin_addr.s_addr; if ((ipaddr.s_addr & mask) != (ina & mask)) continue; strlcpy(ifname, addr->ifa_name, sizeof(ifname)); break; } if (addr == NULL) { warnx("No interface matched %s", inet_ntoa(ipaddr)); freeifaddrs(ifaddrs); return -1; } for (addr = ifaddrs; addr; addr = addr->ifa_next) { if (addr->ifa_addr == NULL || addr->ifa_addr->sa_family != AF_LINK) continue; if (strcmp(ifname, addr->ifa_name) != 0) continue; memcpy(sdl, addr->ifa_addr, sizeof(*sdl)); freeifaddrs(ifaddrs); return 0; } warnx("No link address for interface %s", ifname); freeifaddrs(ifaddrs); return -1; } static struct in_nbrinfo * getnbrinfo(const char *ifname, struct in_addr *addr) { static struct in_nbrinfo nbi, *nbip; int s; if ((s = prog_socket(AF_INET, SOCK_DGRAM, 0)) == -1) err(1, "socket"); (void)memset(&nbi, 0, sizeof(nbi)); (void)strlcpy(nbi.ifname, ifname, sizeof(nbi.ifname)); nbi.addr = *addr; if (prog_ioctl(s, SIOCGNBRINFO, &nbi) == -1) { warn("ioctl(SIOCGNBRINFO)"); nbip = NULL; } else nbip = &nbi; (void)prog_close(s); return nbip; } static const char * sec2str(time_t total) { static char result[256]; int days, hours, mins, secs; int first = 1; char *p = result; char *ep = &result[sizeof(result)]; int n; days = total / 3600 / 24; hours = (total / 3600) % 24; mins = (total / 60) % 60; secs = total % 60; if (days) { first = 0; n = snprintf(p, (size_t)(ep - p), "%dd", days); if (n < 0 || n >= ep - p) return "?"; p += n; } if (!first || hours) { first = 0; n = snprintf(p, (size_t)(ep - p), "%dh", hours); if (n < 0 || n >= ep - p) return "?"; p += n; } if (!first || mins) { first = 0; n = snprintf(p, (size_t)(ep - p), "%dm", mins); if (n < 0 || n >= ep - p) return "?"; p += n; } (void)snprintf(p, (size_t)(ep - p), "%ds", secs); return(result); }