| /* 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 <arpa/inet.h> |
| #include <net/if.h> |
| #include <netinet/ether.h> |
| #include <netpacket/packet.h> |
| |
| #include "libbb.h" |
| |
| /* We don't expect to see 1000+ seconds delay, unsigned is enough */ |
| #define MONOTONIC_US() ((unsigned)monotonic_us()) |
| |
| enum { |
| DAD = 1, |
| UNSOLICITED = 2, |
| ADVERT = 4, |
| QUIET = 8, |
| QUIT_ON_REPLY = 16, |
| BCAST_ONLY = 32, |
| UNICASTING = 64 |
| }; |
| |
| struct globals { |
| struct in_addr src; |
| struct in_addr dst; |
| struct sockaddr_ll me; |
| struct sockaddr_ll he; |
| int sock_fd; |
| |
| int count; // = -1; |
| unsigned last; |
| unsigned timeout_us; |
| unsigned start; |
| |
| unsigned sent; |
| unsigned brd_sent; |
| unsigned received; |
| unsigned brd_recv; |
| unsigned req_recv; |
| }; |
| #define G (*(struct globals*)&bb_common_bufsiz1) |
| #define src (G.src ) |
| #define dst (G.dst ) |
| #define me (G.me ) |
| #define he (G.he ) |
| #define sock_fd (G.sock_fd ) |
| #define count (G.count ) |
| #define last (G.last ) |
| #define timeout_us (G.timeout_us) |
| #define start (G.start ) |
| #define sent (G.sent ) |
| #define brd_sent (G.brd_sent ) |
| #define received (G.received ) |
| #define brd_recv (G.brd_recv ) |
| #define req_recv (G.req_recv ) |
| #define INIT_G() do { \ |
| count = -1; \ |
| } while (0) |
| |
| // If GNUisms are not available... |
| //static void *mempcpy(void *_dst, const void *_src, int n) |
| //{ |
| // memcpy(_dst, _src, n); |
| // return (char*)_dst + n; |
| //} |
| |
| static int send_pack(struct in_addr *src_addr, |
| struct in_addr *dst_addr, struct sockaddr_ll *ME, |
| struct sockaddr_ll *HE) |
| { |
| int err; |
| unsigned char buf[256]; |
| struct arphdr *ah = (struct arphdr *) buf; |
| unsigned char *p = (unsigned char *) (ah + 1); |
| |
| 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 = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST); |
| |
| p = mempcpy(p, &ME->sll_addr, ah->ar_hln); |
| p = mempcpy(p, src_addr, 4); |
| |
| if (option_mask32 & ADVERT) |
| p = mempcpy(p, &ME->sll_addr, ah->ar_hln); |
| else |
| p = mempcpy(p, &HE->sll_addr, ah->ar_hln); |
| |
| p = mempcpy(p, dst_addr, 4); |
| |
| err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE)); |
| if (err == p - buf) { |
| last = MONOTONIC_US(); |
| sent++; |
| if (!(option_mask32 & UNICASTING)) |
| brd_sent++; |
| } |
| return err; |
| } |
| |
| static void finish(void) NORETURN; |
| static void finish(void) |
| { |
| if (!(option_mask32 & QUIET)) { |
| printf("Sent %u probe(s) (%u broadcast(s))\n" |
| "Received %u repl%s" |
| " (%u request(s), %u broadcast(s))\n", |
| sent, brd_sent, |
| received, (received == 1) ? "ies" : "y", |
| req_recv, brd_recv); |
| } |
| if (option_mask32 & DAD) |
| exit(!!received); |
| if (option_mask32 & UNSOLICITED) |
| exit(EXIT_SUCCESS); |
| exit(!received); |
| } |
| |
| static void catcher(void) |
| { |
| unsigned now; |
| |
| now = MONOTONIC_US(); |
| if (start == 0) |
| start = now; |
| |
| if (count == 0 || (timeout_us && (now - start) > timeout_us)) |
| finish(); |
| |
| /* count < 0 means "infinite count" */ |
| if (count > 0) |
| count--; |
| |
| if (last == 0 || (now - last) > 500000) { |
| send_pack(&src, &dst, &me, &he); |
| if (count == 0 && (option_mask32 & UNSOLICITED)) |
| finish(); |
| } |
| alarm(1); |
| } |
| |
| static bool 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; |
| /* moves below assume in_addr is 4 bytes big, ensure that */ |
| struct BUG_in_addr_must_be_4 { |
| char BUG_in_addr_must_be_4[ |
| sizeof(struct in_addr) == 4 ? 1 : -1 |
| ]; |
| char BUG_s_addr_must_be_4[ |
| sizeof(src_ip.s_addr) == 4 ? 1 : -1 |
| ]; |
| }; |
| |
| /* Filter out wild packets */ |
| if (FROM->sll_pkttype != PACKET_HOST |
| && FROM->sll_pkttype != PACKET_BROADCAST |
| && FROM->sll_pkttype != PACKET_MULTICAST) |
| return false; |
| |
| /* Only these types are recognised */ |
| if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY)) |
| return false; |
| |
| /* 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 false; |
| |
| /* Protocol must be IP. */ |
| if (ah->ar_pro != htons(ETH_P_IP) |
| || (ah->ar_pln != 4) |
| || (ah->ar_hln != me.sll_halen) |
| || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln)))) |
| return false; |
| |
| move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln); |
| move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln); |
| |
| if (dst.s_addr != src_ip.s_addr) |
| return false; |
| if (!(option_mask32 & DAD)) { |
| if ((src.s_addr != dst_ip.s_addr) |
| || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))) |
| return false; |
| } 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 ((memcmp(p, &me.sll_addr, me.sll_halen) == 0) |
| || (src.s_addr && src.s_addr != dst_ip.s_addr)) |
| return false; |
| } |
| if (!(option_mask32 & QUIET)) { |
| int s_printed = 0; |
| |
| printf("%scast re%s from %s [%s]", |
| FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad", |
| ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest", |
| 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) { |
| unsigned diff = MONOTONIC_US() - last; |
| printf(" %u.%03ums\n", diff / 1000, diff % 1000); |
| } 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 (option_mask32 & QUIT_ON_REPLY) |
| finish(); |
| if (!(option_mask32 & BCAST_ONLY)) { |
| memcpy(he.sll_addr, p, me.sll_halen); |
| option_mask32 |= UNICASTING; |
| } |
| return true; |
| } |
| |
| int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int arping_main(int argc UNUSED_PARAM, char **argv) |
| { |
| const char *device = "eth0"; |
| char *source = NULL; |
| char *target; |
| unsigned char *packet; |
| char *err_str; |
| |
| INIT_G(); |
| |
| sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0); |
| |
| // Drop suid root privileges |
| // Need to remove SUID_NEVER from applets.h for this to work |
| //xsetuid(getuid()); |
| |
| err_str = xasprintf("interface %s %%s", device); |
| { |
| unsigned opt; |
| char *str_timeout; |
| |
| /* Dad also sets quit_on_reply. |
| * Advert also sets unsolicited. |
| */ |
| opt_complementary = "=1:Df:AU:c+"; |
| opt = getopt32(argv, "DUAqfbc:w:I:s:", |
| &count, &str_timeout, &device, &source); |
| if (opt & 0x80) /* -w: timeout */ |
| timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000; |
| //if (opt & 0x200) /* -s: source */ |
| option_mask32 &= 0x3f; /* set respective flags */ |
| } |
| |
| target = argv[optind]; |
| |
| xfunc_error_retval = 2; |
| |
| { |
| struct ifreq ifr; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy_IFNAMSIZ(ifr.ifr_name, device); |
| /* We use ifr.ifr_name in error msg so that problem |
| * with truncated name will be visible */ |
| ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found"); |
| me.sll_ifindex = ifr.ifr_ifindex; |
| |
| xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr); |
| |
| if (!(ifr.ifr_flags & IFF_UP)) { |
| bb_error_msg_and_die(err_str, "is down"); |
| } |
| if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) { |
| bb_error_msg(err_str, "is not ARPable"); |
| return (option_mask32 & DAD ? 0 : 2); |
| } |
| } |
| |
| /* if (!inet_aton(target, &dst)) - not needed */ { |
| len_and_sockaddr *lsa; |
| lsa = xhost_and_af2sockaddr(target, 0, AF_INET); |
| dst = lsa->u.sin.sin_addr; |
| if (ENABLE_FEATURE_CLEAN_UP) |
| free(lsa); |
| } |
| |
| if (source && !inet_aton(source, &src)) { |
| bb_error_msg_and_die("invalid source address %s", source); |
| } |
| |
| if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0) |
| src = dst; |
| |
| if (!(option_mask32 & DAD) || src.s_addr) { |
| struct sockaddr_in saddr; |
| int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0); |
| |
| setsockopt_bindtodevice(probe_fd, device); |
| memset(&saddr, 0, sizeof(saddr)); |
| saddr.sin_family = AF_INET; |
| if (src.s_addr) { |
| /* Check that this is indeed our IP */ |
| saddr.sin_addr = src; |
| xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)); |
| } else { /* !(option_mask32 & DAD) case */ |
| /* Find IP address on this iface */ |
| socklen_t alen = sizeof(saddr); |
| |
| saddr.sin_port = htons(1025); |
| saddr.sin_addr = dst; |
| |
| if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1) |
| bb_perror_msg("setsockopt(SO_DONTROUTE)"); |
| xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)); |
| getsockname(probe_fd, (struct sockaddr *) &saddr, &alen); |
| //never happens: |
| //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) |
| // bb_perror_msg_and_die("getsockname"); |
| if (saddr.sin_family != AF_INET) |
| bb_error_msg_and_die("no IP address configured"); |
| src = saddr.sin_addr; |
| } |
| close(probe_fd); |
| } |
| |
| me.sll_family = AF_PACKET; |
| //me.sll_ifindex = ifindex; - done before |
| me.sll_protocol = htons(ETH_P_ARP); |
| xbind(sock_fd, (struct sockaddr *) &me, sizeof(me)); |
| |
| { |
| socklen_t alen = sizeof(me); |
| getsockname(sock_fd, (struct sockaddr *) &me, &alen); |
| //never happens: |
| //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1) |
| // bb_perror_msg_and_die("getsockname"); |
| } |
| if (me.sll_halen == 0) { |
| bb_error_msg(err_str, "is not ARPable (no ll address)"); |
| return (option_mask32 & DAD ? 0 : 2); |
| } |
| he = me; |
| memset(he.sll_addr, -1, he.sll_halen); |
| |
| if (!(option_mask32 & QUIET)) { |
| /* inet_ntoa uses static storage, can't use in same printf */ |
| printf("ARPING to %s", inet_ntoa(dst)); |
| printf(" from %s via %s\n", inet_ntoa(src), device); |
| } |
| |
| signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish); |
| signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher); |
| |
| catcher(); |
| |
| packet = xmalloc(4096); |
| while (1) { |
| sigset_t sset, osset; |
| struct sockaddr_ll from; |
| socklen_t alen = sizeof(from); |
| int cc; |
| |
| cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen); |
| if (cc < 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); |
| } |
| } |