| /* vi: set sw=4 ts=4: */ |
| /* |
| * arping.c - Ping hosts by ARP requests/replies |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| * |
| * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> |
| * Busybox port: Nick Fedchik <nick@fedchik.org.ua> |
| */ |
| |
| #include <sys/ioctl.h> |
| #include <signal.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" |
| |
| static struct in_addr src; |
| static struct in_addr dst; |
| static struct sockaddr_ll me; |
| static struct sockaddr_ll he; |
| static struct timeval last; |
| |
| enum cfg_e { |
| dad = 1, |
| unsolicited = 2, |
| advert = 4, |
| quiet = 8, |
| quit_on_reply = 16, |
| broadcast_only = 32, |
| unicasting = 64 |
| }; |
| static int cfg; |
| |
| static int s; |
| static int count = -1; |
| static int timeout; |
| static int sent; |
| static int brd_sent; |
| static int received; |
| static int brd_recv; |
| static int req_recv; |
| |
| |
| #define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \ |
| ((tv1).tv_usec-(tv2).tv_usec)/1000 ) |
| 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; |
| RESERVE_CONFIG_UBUFFER(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 = cfg&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 (cfg&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 (!(cfg&unicasting)) |
| brd_sent++; |
| } |
| RELEASE_CONFIG_BUFFER(buf); |
| return err; |
| } |
| |
| static void finish(void) |
| { |
| if (!(cfg&quiet)) { |
| printf("Sent %d probes (%d broadcast(s))\n" |
| "Received %d repl%s", |
| sent, brd_sent, |
| 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 (cfg&dad) |
| exit(!!received); |
| if (cfg&unsolicited) |
| exit(0); |
| exit(!received); |
| } |
| |
| static void catcher(void) |
| { |
| struct timeval tv; |
| static 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 && cfg&unsolicited) |
| finish(); |
| } |
| alarm(1); |
| } |
| |
| static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM) |
| { |
| struct arphdr *ah = (struct arphdr *) buf; |
| unsigned char *p = (unsigned char *) (ah + 1); |
| struct in_addr src_ip, dst_ip; |
| |
| /* 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 (!(cfg&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 (!(cfg&quiet)) { |
| int s_printed = 0; |
| struct timeval tv; |
| |
| gettimeofday(&tv, NULL); |
| |
| printf("%s %s from %s [%s]", |
| FROM->sll_pkttype == PACKET_HOST ? "Unicast" : "Broadcast", |
| ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request", |
| inet_ntoa(src_ip), |
| 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 (cfg&quit_on_reply) |
| finish(); |
| if (!(cfg&broadcast_only)) { |
| memcpy(he.sll_addr, p, me.sll_halen); |
| cfg |= unicasting; |
| } |
| return 1; |
| } |
| |
| int arping_main(int argc, char **argv) |
| { |
| char *device = "eth0"; |
| int ifindex; |
| char *source = NULL; |
| char *target; |
| |
| s = xsocket(PF_PACKET, SOCK_DGRAM, 0); |
| |
| // Drop suid root privileges |
| xsetuid(getuid()); |
| |
| { |
| unsigned long opt; |
| char *_count, *_timeout; |
| |
| /* Dad also sets quit_on_reply. |
| * Advert also sets unsolicited. |
| */ |
| bb_opt_complementally = "Df:AU"; |
| opt = bb_getopt_ulflags(argc, argv, "DUAqfbc:w:i:s:", |
| &_count, &_timeout, &device, &source); |
| cfg |= opt & 0x3f; /* set respective flags */ |
| if (opt & 0x40) /* -c: count */ |
| count = atoi(_count); |
| if (opt & 0x80) /* -w: timeout */ |
| timeout = atoi(_timeout); |
| if (opt & 0x100) { /* -i: interface */ |
| if (strlen(device) > IF_NAMESIZE) { |
| bb_error_msg_and_die("interface name '%s' is too long", |
| device); |
| } |
| } |
| //if (opt & 0x200) /* -s: source */ |
| } |
| argc -= optind; |
| argv += optind; |
| |
| if (argc != 1) |
| bb_show_usage(); |
| |
| target = *argv; |
| |
| xfunc_error_retval = 2; |
| |
| { |
| struct ifreq ifr; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, device, IFNAMSIZ - 1); |
| if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) { |
| bb_error_msg_and_die("interface %s not found", device); |
| } |
| ifindex = ifr.ifr_ifindex; |
| |
| if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) { |
| bb_error_msg_and_die("SIOCGIFFLAGS"); |
| } |
| if (!(ifr.ifr_flags & IFF_UP)) { |
| bb_error_msg_and_die("interface %s is down", device); |
| } |
| if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) { |
| bb_error_msg("interface %s is not ARPable", device); |
| exit(cfg&dad ? 0 : 2); |
| } |
| } |
| |
| if (!inet_aton(target, &dst)) { |
| struct hostent *hp; |
| |
| hp = gethostbyname2(target, AF_INET); |
| if (!hp) { |
| bb_error_msg_and_die("invalid or unknown target %s", target); |
| } |
| memcpy(&dst, hp->h_addr, 4); |
| } |
| |
| if (source && !inet_aton(source, &src)) { |
| bb_error_msg_and_die("invalid source address %s", source); |
| } |
| |
| if (!(cfg&dad) && cfg&unsolicited && src.s_addr == 0) |
| src = dst; |
| |
| if (!(cfg&dad) || src.s_addr) { |
| struct sockaddr_in saddr; |
| int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0); |
| |
| 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_and_die("bind"); |
| } |
| } else if (!(cfg&dad)) { |
| int on = 1; |
| socklen_t 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) |
| bb_perror_msg("warning: setsockopt(SO_DONTROUTE)"); |
| if (connect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) |
| == -1) { |
| bb_error_msg_and_die("connect"); |
| } |
| if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == |
| -1) { |
| bb_error_msg_and_die("getsockname"); |
| } |
| 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_and_die("bind"); |
| } |
| |
| { |
| socklen_t alen = sizeof(me); |
| |
| if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) { |
| bb_error_msg_and_die("getsockname"); |
| } |
| } |
| if (me.sll_halen == 0) { |
| bb_error_msg("Interface \"%s\" is not ARPable (no ll address)", device); |
| exit(cfg&dad ? 0 : 2); |
| } |
| he = me; |
| memset(he.sll_addr, -1, he.sll_halen); |
| |
| if (!(cfg&quiet)) { |
| printf("ARPING to %s from %s via %s\n", |
| inet_ntoa(dst), inet_ntoa(src), |
| device ? device : "unknown"); |
| } |
| |
| if (!src.s_addr && !(cfg&dad)) { |
| bb_error_msg_and_die("no src address in the non-DAD mode"); |
| } |
| |
| { |
| 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; |
| RESERVE_CONFIG_UBUFFER(packet, 4096); |
| struct sockaddr_ll from; |
| socklen_t alen = sizeof(from); |
| int cc; |
| |
| if ((cc = recvfrom(s, packet, 4096, 0, |
| (struct sockaddr *) &from, &alen)) < 0) { |
| bb_perror_msg("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); |
| RELEASE_CONFIG_BUFFER(packet); |
| } |
| } |