/* * arping.c - Ping hosts by ARP requests/replies * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> * Busybox port: Nick Fedchik <nick@fedchik.org.ua> */ #include <sys/ioctl.h> #include <sys/signal.h> #include <sys/time.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <arpa/inet.h> #include <net/if.h> #include <netinet/ether.h> #include <netpacket/packet.h> #include "busybox.h" #define APPLET_NAME "arping" struct in_addr src; struct in_addr dst; struct sockaddr_ll me; struct sockaddr_ll he; struct timeval last; int dad; int unsolicited; int advert; int quiet; int quit_on_reply = 0; int count = -1; int timeout; int unicasting; int s; int broadcast_only; int sent; int brd_sent; int received; int brd_recv; int req_recv; #define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \ ((tv1).tv_usec-(tv2).tv_usec)/1000 ) #if 0 static void set_signal(int signo, void (*handler) (void)) { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = (void (*)(int)) handler; sa.sa_flags = SA_RESTART; sigaction(signo, &sa, NULL); } #endif static int send_pack(int sock, struct in_addr *src_addr, struct in_addr *dst_addr, struct sockaddr_ll *ME, struct sockaddr_ll *HE) { int err; struct timeval now; unsigned char buf[256]; struct arphdr *ah = (struct arphdr *) buf; unsigned char *p = (unsigned char *) (ah + 1); ah->ar_hrd = htons(ME->sll_hatype); ah->ar_hrd = htons(ARPHRD_ETHER); ah->ar_pro = htons(ETH_P_IP); ah->ar_hln = ME->sll_halen; ah->ar_pln = 4; ah->ar_op = advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST); memcpy(p, &ME->sll_addr, ah->ar_hln); p += ME->sll_halen; memcpy(p, src_addr, 4); p += 4; if (advert) memcpy(p, &ME->sll_addr, ah->ar_hln); else memcpy(p, &HE->sll_addr, ah->ar_hln); p += ah->ar_hln; memcpy(p, dst_addr, 4); p += 4; gettimeofday(&now, NULL); err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE)); if (err == p - buf) { last = now; sent++; if (!unicasting) brd_sent++; } return err; } void finish(void) { if (!quiet) { printf("Sent %d probes (%d broadcast(s))\n", sent, brd_sent); printf("Received %d repl%s", received, (received > 1) ? "ies" : "y"); if (brd_recv || req_recv) { printf(" ("); if (req_recv) printf("%d request(s)", req_recv); if (brd_recv) printf("%s%d broadcast(s)", req_recv ? ", " : "", brd_recv); putchar(')'); } putchar('\n'); fflush(stdout); } if (dad) exit(!!received); if (unsolicited) exit(0); exit(!received); } void catcher(void) { struct timeval tv; struct timeval start; gettimeofday(&tv, NULL); if (start.tv_sec == 0) start = tv; if (count-- == 0 || (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500)) finish(); if (last.tv_sec == 0 || MS_TDIFF(tv, last) > 500) { send_pack(s, &src, &dst, &me, &he); if (count == 0 && unsolicited) finish(); } alarm(1); } int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM) { struct timeval tv; struct arphdr *ah = (struct arphdr *) buf; unsigned char *p = (unsigned char *) (ah + 1); struct in_addr src_ip, dst_ip; gettimeofday(&tv, NULL); /* Filter out wild packets */ if (FROM->sll_pkttype != PACKET_HOST && FROM->sll_pkttype != PACKET_BROADCAST && FROM->sll_pkttype != PACKET_MULTICAST) return 0; /* Only these types are recognised */ if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY)) return 0; /* ARPHRD check and this darned FDDI hack here :-( */ if (ah->ar_hrd != htons(FROM->sll_hatype) && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER))) return 0; /* Protocol must be IP. */ if (ah->ar_pro != htons(ETH_P_IP)) return 0; if (ah->ar_pln != 4) return 0; if (ah->ar_hln != me.sll_halen) return 0; if (len < sizeof(*ah) + 2 * (4 + ah->ar_hln)) return 0; memcpy(&src_ip, p + ah->ar_hln, 4); memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4); if (!dad) { if (src_ip.s_addr != dst.s_addr) return 0; if (src.s_addr != dst_ip.s_addr) return 0; if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)) return 0; } else { /* DAD packet was: src_ip = 0 (or some src) src_hw = ME dst_ip = tested address dst_hw = <unspec> We fail, if receive request/reply with: src_ip = tested_address src_hw != ME if src_ip in request was not zero, check also that it matches to dst_ip, otherwise dst_ip/dst_hw do not matter. */ if (src_ip.s_addr != dst.s_addr) return 0; if (memcmp(p, &me.sll_addr, me.sll_halen) == 0) return 0; if (src.s_addr && src.s_addr != dst_ip.s_addr) return 0; } if (!quiet) { int s_printed = 0; printf("%s ", FROM->sll_pkttype == PACKET_HOST ? "Unicast" : "Broadcast"); printf("%s from ", ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request"); printf("%s ", inet_ntoa(src_ip)); printf("[%s]", ether_ntoa((struct ether_addr *) p)); if (dst_ip.s_addr != src.s_addr) { printf("for %s ", inet_ntoa(dst_ip)); s_printed = 1; } if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) { if (!s_printed) printf("for "); printf("[%s]", ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4)); } if (last.tv_sec) { long usecs = (tv.tv_sec - last.tv_sec) * 1000000 + tv.tv_usec - last.tv_usec; long msecs = (usecs + 500) / 1000; usecs -= msecs * 1000 - 500; printf(" %ld.%03ldms\n", msecs, usecs); } else { printf(" UNSOLICITED?\n"); } fflush(stdout); } received++; if (FROM->sll_pkttype != PACKET_HOST) brd_recv++; if (ah->ar_op == htons(ARPOP_REQUEST)) req_recv++; if (quit_on_reply) finish(); if (!broadcast_only) { memcpy(he.sll_addr, p, me.sll_halen); unicasting = 1; } return 1; } int arping_main(int argc, char **argv) { int socket_errno; int ch; uid_t uid = getuid(); char *device = "eth0"; int ifindex = 0; char *source = NULL; char *target; s = socket(PF_PACKET, SOCK_DGRAM, 0); socket_errno = errno; setuid(uid); while ((ch = getopt(argc, argv, "h?bfDUAqc:w:s:I:")) != EOF) { switch (ch) { case 'b': broadcast_only = 1; break; case 'D': dad++; quit_on_reply = 1; break; case 'U': unsolicited++; break; case 'A': advert++; unsolicited++; break; case 'q': quiet++; break; case 'c': count = atoi(optarg); break; case 'w': timeout = atoi(optarg); break; case 'I': if (optarg == NULL) bb_show_usage(); if (bb_strlen(optarg) > IF_NAMESIZE) { bb_error_msg("Interface name `%s' must be less than %d", optarg, IF_NAMESIZE); exit(2); } device = optarg; break; case 'f': quit_on_reply = 1; break; case 's': source = optarg; break; case 'h': case '?': default: bb_show_usage(); } } argc -= optind; argv += optind; if (argc != 1) bb_show_usage(); target = *argv; if (s < 0) { bb_error_msg("socket"); exit(socket_errno); } { struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_name, device, IFNAMSIZ - 1); if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) { bb_error_msg("Interface %s not found", device); exit(2); } ifindex = ifr.ifr_ifindex; if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) { bb_error_msg("SIOCGIFFLAGS"); exit(2); } if (!(ifr.ifr_flags & IFF_UP)) { bb_error_msg("Interface %s is down", device); exit(2); } if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) { bb_error_msg("Interface %s is not ARPable", device); exit(dad ? 0 : 2); } } if (!inet_aton(target, &dst)) { struct hostent *hp; hp = gethostbyname2(target, AF_INET); if (!hp) { bb_error_msg("invalid or unknown target %s", target); exit(2); } memcpy(&dst, hp->h_addr, 4); } if (source && !inet_aton(source, &src)) { bb_error_msg("invalid source address %s", source); exit(2); } if (!dad && unsolicited && src.s_addr == 0) src = dst; if (!dad || src.s_addr) { struct sockaddr_in saddr; int probe_fd = socket(AF_INET, SOCK_DGRAM, 0); if (probe_fd < 0) { bb_error_msg("socket"); exit(2); } if (device) { if (setsockopt (probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1) bb_error_msg("WARNING: interface %s is ignored", device); } memset(&saddr, 0, sizeof(saddr)); saddr.sin_family = AF_INET; if (src.s_addr) { saddr.sin_addr = src; if (bind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) == -1) { bb_error_msg("bind"); exit(2); } } else if (!dad) { int on = 1; int alen = sizeof(saddr); saddr.sin_port = htons(1025); saddr.sin_addr = dst; if (setsockopt (probe_fd, SOL_SOCKET, SO_DONTROUTE, (char *) &on, sizeof(on)) == -1) perror("WARNING: setsockopt(SO_DONTROUTE)"); if (connect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) == -1) { bb_error_msg("connect"); exit(2); } if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) { bb_error_msg("getsockname"); exit(2); } src = saddr.sin_addr; } close(probe_fd); }; me.sll_family = AF_PACKET; me.sll_ifindex = ifindex; me.sll_protocol = htons(ETH_P_ARP); if (bind(s, (struct sockaddr *) &me, sizeof(me)) == -1) { bb_error_msg("bind"); exit(2); } { int alen = sizeof(me); if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) { bb_error_msg("getsockname"); exit(2); } } if (me.sll_halen == 0) { bb_error_msg("Interface \"%s\" is not ARPable (no ll address)", device); exit(dad ? 0 : 2); } he = me; memset(he.sll_addr, -1, he.sll_halen); if (!quiet) { printf("ARPING to %s", inet_ntoa(dst)); printf(" from %s via %s\n", inet_ntoa(src), device ? device : "unknown"); } if (!src.s_addr && !dad) { bb_error_msg("no src address in the non-DAD mode"); exit(2); } { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_flags = SA_RESTART; sa.sa_handler = (void (*)(int)) finish; sigaction(SIGINT, &sa, NULL); sa.sa_handler = (void (*)(int)) catcher; sigaction(SIGALRM, &sa, NULL); } catcher(); while (1) { sigset_t sset, osset; char packet[4096]; struct sockaddr_ll from; int alen = sizeof(from); int cc; if ((cc = recvfrom(s, packet, sizeof(packet), 0, (struct sockaddr *) &from, &alen)) < 0) { perror("recvfrom"); continue; } sigemptyset(&sset); sigaddset(&sset, SIGALRM); sigaddset(&sset, SIGINT); sigprocmask(SIG_BLOCK, &sset, &osset); recv_pack(packet, cc, &from); sigprocmask(SIG_SETMASK, &osset, NULL); } }