/* * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. * * @(#) Copyright (c) 1984, 1993 The Regents of the University of California. All rights reserved. * @(#)from: arp.c 8.2 (Berkeley) 1/2/94 * $FreeBSD: src/usr.sbin/arp/arp.c,v 1.22.2.12 2003/04/16 10:02:37 ru Exp $ * $DragonFly: src/usr.sbin/arp/arp.c,v 1.8 2006/01/19 22:19:31 dillon Exp $ */ /* * 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 void search(u_long addr, void (*action)(struct sockaddr_dl *sdl, struct sockaddr_inarp *sin, struct rt_msghdr *rtm)); void print_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *addr, struct rt_msghdr *rtm); void nuke_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *addr, struct rt_msghdr *rtm); int delete(char *host, char *info); void usage(void); int set(int argc, char **argv); int get(char *host); int file(char *name); void getsocket(void); int my_ether_aton(char *a, struct ether_addr *n); int rtmsg(int cmd); int get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr); static int pid; static int nflag; /* no reverse dns lookups */ static int aflag; /* do it for all entries */ static int cpuflag = -1; static int s = -1; struct sockaddr_in so_mask; struct sockaddr_inarp blank_sin, sin_m; struct sockaddr_dl blank_sdl, sdl_m; int expire_time, flags, doing_proxy, proxy_only, found_entry; struct { struct rt_msghdr m_rtm; char m_space[512]; } m_rtmsg; /* which function we're supposed to do */ #define F_GET 1 #define F_SET 2 #define F_FILESET 3 #define F_REPLACE 4 #define F_DELETE 5 #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define SETFUNC(f) { if (func) usage(); func = (f); } int main(int argc, char **argv) { int ch, func = 0; int rtn = 0; pid = getpid(); while ((ch = getopt(argc, argv, "ac:ndfsS")) != -1) switch((char)ch) { case 'a': aflag = 1; break; case 'c': cpuflag = strtol(optarg, NULL, 0); break; case 'd': SETFUNC(F_DELETE); break; case 'n': nflag = 1; break; case 'S': SETFUNC(F_REPLACE); break; case 's': SETFUNC(F_SET); break; case 'f' : SETFUNC(F_FILESET); break; case '?': default: usage(); } argc -= optind; argv += optind; bzero(&so_mask, sizeof(so_mask)); so_mask.sin_len = 8; so_mask.sin_addr.s_addr = 0xffffffff; bzero(&blank_sin, sizeof(blank_sin)); blank_sin.sin_len = sizeof(blank_sin); blank_sin.sin_family = AF_INET; bzero(&blank_sdl, sizeof(blank_sdl)); blank_sdl.sdl_len = sizeof(blank_sdl); blank_sdl.sdl_family = AF_LINK; if (!func) func = F_GET; switch (func) { case F_GET: if (aflag) { if (argc != 0) usage(); search(0, print_entry); } else { if (argc != 1) usage(); get(argv[0]); } break; case F_SET: case F_REPLACE: if (argc < 2 || argc > 6) usage(); if (func == F_REPLACE) delete(argv[0], NULL); rtn = set(argc, argv) ? 1 : 0; break; case F_DELETE: if (aflag) { if (argc != 0) usage(); search(0, nuke_entry); } else { if (argc < 1 || argc > 2) usage(); rtn = delete(argv[0], argv[1]); } break; case F_FILESET: if (argc != 1) usage(); rtn = file(argv[0]); break; } return(rtn); } /* * Process a file to set standard arp entries */ int file(char *name) { FILE *fp; int i, retval; char line[100], arg[5][50], *args[5], *p; if ((fp = fopen(name, "r")) == NULL) errx(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) { if ((p = strchr(line, '#')) != NULL) *p = '\0'; for (p = line; isblank(*p); p++); if (*p == '\n' || *p == '\0') continue; i = sscanf(p, "%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) { s = socket(PF_ROUTE, SOCK_RAW, 0); if (s < 0) err(1, "socket"); } } /* * Set an individual arp entry */ int set(int argc, char **argv) { struct hostent *hp; struct sockaddr_inarp *addr = &sin_m; struct sockaddr_dl *sdl; struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); struct ether_addr *ea; char *host = argv[0], *eaddr = argv[1]; getsocket(); argc -= 2; argv += 2; sdl_m = blank_sdl; sin_m = blank_sin; addr->sin_addr.s_addr = inet_addr(host); if (addr->sin_addr.s_addr == INADDR_NONE) { if (!(hp = gethostbyname(host))) { warnx("%s: %s", host, hstrerror(h_errno)); return(1); } bcopy((char *)hp->h_addr, (char *)&addr->sin_addr, sizeof(addr->sin_addr)); } doing_proxy = flags = proxy_only = expire_time = 0; while (argc-- > 0) { if (strncmp(argv[0], "temp", 4) == 0) { struct timeval tv; gettimeofday(&tv, 0); expire_time = tv.tv_sec + 20 * 60; } else if (strncmp(argv[0], "pub", 3) == 0) { flags |= RTF_ANNOUNCE; doing_proxy = 1; if (argc && strncmp(argv[1], "only", 3) == 0) { proxy_only = 1; sin_m.sin_other = SIN_PROXY; argc--; argv++; } } else if (strncmp(argv[0], "trail", 5) == 0) { printf("%s: Sending trailers is no longer supported\n", host); } argv++; } ea = (struct ether_addr *)LLADDR(&sdl_m); if (doing_proxy && !strcmp(eaddr, "auto")) { if (!get_ether_addr(addr->sin_addr.s_addr, ea)) { printf("no interface found for %s\n", inet_ntoa(addr->sin_addr)); return(1); } sdl_m.sdl_alen = ETHER_ADDR_LEN; } else { if (my_ether_aton(eaddr, ea) == 0) sdl_m.sdl_alen = ETHER_ADDR_LEN; } tryagain: if (rtmsg(RTM_GET) < 0) { warn("%s", host); return(1); } addr = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *)(ROUNDUP(addr->sin_len) + (char *)addr); if (addr->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_L2VLAN: goto overwrite; } if (doing_proxy == 0) { printf("set: can only proxy for %s\n", host); return(1); } if (sin_m.sin_other & SIN_PROXY) { printf("set: proxy entry exists for non 802 device\n"); return(1); } sin_m.sin_other = SIN_PROXY; proxy_only = 1; goto tryagain; } overwrite: if (sdl->sdl_family != AF_LINK) { 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; return(rtmsg(RTM_ADD)); } /* * Display an individual arp entry */ int get(char *host) { struct hostent *hp; struct sockaddr_inarp *addr = &sin_m; sin_m = blank_sin; addr->sin_addr.s_addr = inet_addr(host); if (addr->sin_addr.s_addr == INADDR_NONE) { if (!(hp = gethostbyname(host))) errx(1, "%s: %s", host, hstrerror(h_errno)); bcopy((char *)hp->h_addr, (char *)&addr->sin_addr, sizeof(addr->sin_addr)); } search(addr->sin_addr.s_addr, print_entry); if (found_entry == 0) { printf("%s (%s) -- no entry\n", host, inet_ntoa(addr->sin_addr)); return(1); } return(0); } /* * Delete an arp entry */ int delete(char *host, char *info) { struct hostent *hp; struct sockaddr_inarp *addr = &sin_m; struct rt_msghdr *rtm = &m_rtmsg.m_rtm; struct sockaddr_dl *sdl; getsocket(); sin_m = blank_sin; if (info) { if (strncmp(info, "pub", 3) == 0) sin_m.sin_other = SIN_PROXY; else usage(); } addr->sin_addr.s_addr = inet_addr(host); if (addr->sin_addr.s_addr == INADDR_NONE) { if (!(hp = gethostbyname(host))) { warnx("%s: %s", host, hstrerror(h_errno)); return(1); } bcopy((char *)hp->h_addr, (char *)&addr->sin_addr, sizeof(addr->sin_addr)); } tryagain: if (rtmsg(RTM_GET) < 0) { warn("%s", host); return(1); } addr = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *)(ROUNDUP(addr->sin_len) + (char *)addr); if (addr->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_L2VLAN: goto delete; } } if (sin_m.sin_other & SIN_PROXY) { fprintf(stderr, "delete: can't locate %s\n",host); return(1); } else { sin_m.sin_other = SIN_PROXY; goto tryagain; } delete: if (sdl->sdl_family != AF_LINK) { printf("cannot locate %s\n", host); return(1); } if (aflag && (rtm->rtm_flags & RTF_STATIC)) { sdl->sdl_alen = 0; sdl->sdl_slen = 0; if (rtmsg(RTM_CHANGE) == 0) { printf("%s (%s) cleared\n", host, inet_ntoa(addr->sin_addr)); return(0); } } else { if (rtmsg(RTM_DELETE) == 0) { printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr)); return(0); } } return(1); } /* * Search the arp table and do some action on matching entries */ void search(u_long addr, void (*action)(struct sockaddr_dl *sdl, struct sockaddr_inarp *sin, struct rt_msghdr *rtm)) { int mib[7]; int miblen; size_t needed; char *lim, *buf, *next; struct rt_msghdr *rtm; struct sockaddr_inarp *sin2; 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 (cpuflag >= 0) { mib[6] = cpuflag; miblen = 7; } else { miblen = 6; } if (sysctl(mib, miblen, NULL, &needed, NULL, 0) < 0) errx(1, "route-sysctl-estimate"); if ((buf = malloc(needed)) == NULL) errx(1, "malloc"); if (sysctl(mib, miblen, buf, &needed, NULL, 0) < 0) errx(1, "actual retrieval of routing table"); lim = buf + needed; for (next = buf; next < lim; next += rtm->rtm_msglen) { rtm = (struct rt_msghdr *)next; sin2 = (struct sockaddr_inarp *)(rtm + 1); sdl = (struct sockaddr_dl *)((char *)sin2 + ROUNDUP(sin2->sin_len)); if (addr) { if (addr != sin2->sin_addr.s_addr) continue; found_entry = 1; } (*action)(sdl, sin2, rtm); } free(buf); } /* * Display an arp entry */ void print_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *addr, struct rt_msghdr *rtm) { const char *host; struct hostent *hp; struct iso88025_sockaddr_dl_data *trld; char ifname[IF_NAMESIZE]; int seg; if (nflag == 0) hp = gethostbyaddr((caddr_t)&(addr->sin_addr), sizeof(addr->sin_addr), AF_INET); else hp = 0; if (hp) host = hp->h_name; else { host = "?"; if (h_errno == TRY_AGAIN) nflag = 1; } printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr)); if (sdl->sdl_alen) printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl))); else printf("(incomplete)"); if (if_indextoname(sdl->sdl_index, ifname) != NULL) printf(" on %s", ifname); if (rtm->rtm_rmx.rmx_expire == 0) printf(" permanent"); if (addr->sin_other & SIN_PROXY) printf(" published (proxy only)"); if (rtm->rtm_addrs & RTA_NETMASK) { addr = (struct sockaddr_inarp *) (ROUNDUP(sdl->sdl_len) + (char *)sdl); if (addr->sin_addr.s_addr == 0xffffffff) printf(" published"); if (addr->sin_len != 8) printf("(weird)"); } switch(sdl->sdl_type) { case IFT_ETHER: printf(" [ethernet]"); break; case IFT_ISO88025: printf(" [token-ring]"); trld = SDL_ISO88025(sdl); if (trld->trld_rcf != 0) { printf(" rt=%x", ntohs(trld->trld_rcf)); for (seg = 0; seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2); seg++) printf(":%x", ntohs(*(trld->trld_route[seg]))); } break; case IFT_L2VLAN: printf(" [vlan]"); break; default: break; } printf("\n"); } /* * Nuke an arp entry */ void nuke_entry(struct sockaddr_dl *sdl __unused, struct sockaddr_inarp *addr, struct rt_msghdr *rtm __unused) { char ip[20]; snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr)); delete(ip, NULL); } int my_ether_aton(char *a, struct ether_addr *n) { struct ether_addr *ea; if ((ea = ether_aton(a)) == NULL) { warnx("invalid Ethernet address '%s'", a); return(1); } *n = *ea; return(0); } void usage(void) { fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n", "usage: arp [-n] hostname", " arp [-n] -a", " arp -d hostname [pub]", " arp -d -a", " arp -s hostname ether_addr [temp] [pub]", " arp -S hostname ether_addr [temp] [pub]", " arp -f filename"); exit(1); } int rtmsg(int cmd) { static int seq; int rlen; struct rt_msghdr *rtm = &m_rtmsg.m_rtm; char *cp = m_rtmsg.m_space; int l; errno = 0; if (cmd == RTM_DELETE || cmd == RTM_CHANGE) goto doit; bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); rtm->rtm_flags = flags; rtm->rtm_version = RTM_VERSION; switch (cmd) { default: errx(1, "internal wrong cmd"); 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 (proxy_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)) { \ bcopy((char *)&s, cp, sizeof(s)); cp += ROUNDUP(sizeof(s));} 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 && cmd != RTM_CHANGE)) { 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); } /* * get_ether_addr - get the hardware address of an interface on the * the same subnet as ipaddr. */ #define MAX_IFS 32 int get_ether_addr(u_int32_t ipaddr, struct ether_addr *hwaddr) { struct ifreq *ifr, *ifend, *ifp; u_int32_t ina, mask; struct sockaddr_dl *dla; struct ifreq ifreq; struct ifconf ifc; struct ifreq ifs[MAX_IFS]; int sock; sock = socket(AF_INET, SOCK_DGRAM, 0); if (sock < 0) err(1, "socket"); ifc.ifc_len = sizeof(ifs); ifc.ifc_req = ifs; if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) { warnx("ioctl(SIOCGIFCONF)"); close(sock); return(0); } /* * Scan through looking for an interface with an Internet * address on the same subnet as `ipaddr'. */ ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len); for (ifr = ifc.ifc_req; ifr < ifend; ) { if (ifr->ifr_addr.sa_family == AF_INET) { ina = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr; strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name)); /* * Check that the interface is up, * and not point-to-point or loopback. */ if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0) continue; if ((ifreq.ifr_flags & (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT| IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST)) goto nextif; /* * Get its netmask and check that it's on * the right subnet. */ if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0) continue; mask = ((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr.s_addr; if ((ipaddr & mask) != (ina & mask)) goto nextif; break; } nextif: ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr))); } if (ifr >= ifend) { close(sock); return(0); } /* * Now scan through again looking for a link-level address * for this interface. */ ifp = ifr; for (ifr = ifc.ifc_req; ifr < ifend; ) { if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 && ifr->ifr_addr.sa_family == AF_LINK) { /* * Found the link-level address - copy it out */ dla = (struct sockaddr_dl *) &ifr->ifr_addr; memcpy(hwaddr, LLADDR(dla), dla->sdl_alen); close (sock); printf("using interface %s for proxy with address ", ifp->ifr_name); printf("%s\n", ether_ntoa(hwaddr)); return(dla->sdl_alen); } ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + MAX(ifr->ifr_addr.sa_len, sizeof(ifr->ifr_addr))); } return(0); }