| /* vi: set sw=4 ts=4: */ |
| /* |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| * |
| * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> |
| * Busybox port: Nick Fedchik <nick@fedchik.org.ua> |
| */ |
| //config:config ARPING |
| //config: bool "arping (9 kb)" |
| //config: default y |
| //config: help |
| //config: Ping hosts by ARP packets. |
| |
| //applet:IF_ARPING(APPLET(arping, BB_DIR_USR_SBIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_ARPING) += arping.o |
| |
| //usage:#define arping_trivial_usage |
| //usage: "[-fqbDUA] [-c CNT] [-w TIMEOUT] [-I IFACE] [-s SRC_IP] DST_IP" |
| //usage:#define arping_full_usage "\n\n" |
| //usage: "Send ARP requests/replies\n" |
| //usage: "\n -f Quit on first ARP reply" |
| //usage: "\n -q Quiet" |
| //usage: "\n -b Keep broadcasting, don't go unicast" |
| //usage: "\n -D Exit with 1 if DST_IP replies" |
| //usage: "\n -U Unsolicited ARP mode, update your neighbors" |
| //usage: "\n -A ARP answer mode, update your neighbors" |
| //usage: "\n -c N Stop after sending N ARP requests" |
| //usage: "\n -w TIMEOUT Seconds to wait for ARP reply" |
| //NB: in iputils-s20160308, iface is mandatory, no default |
| //usage: "\n -I IFACE Interface to use (default eth0)" |
| //usage: "\n -s SRC_IP Sender IP address" |
| //usage: "\n DST_IP Target IP address" |
| |
| #include <arpa/inet.h> |
| #include <net/if.h> |
| #include <netinet/ether.h> |
| #include <netpacket/packet.h> |
| |
| #include "libbb.h" |
| #include "common_bufsiz.h" |
| |
| /* We don't expect to see 1000+ seconds delay, unsigned is enough */ |
| #define MONOTONIC_US() ((unsigned)monotonic_us()) |
| |
| enum { |
| UNSOLICITED = 1 << 0, |
| DAD = 1 << 1, |
| ADVERT = 1 << 2, |
| QUIET = 1 << 3, |
| QUIT_ON_REPLY = 1 << 4, |
| BCAST_ONLY = 1 << 5, |
| UNICASTING = 1 << 6, |
| TIMEOUT = 1 << 7, |
| }; |
| #define GETOPT32(str_timeout, device, source) \ |
| getopt32(argv, "^" \ |
| "UDAqfbc:+w:I:s:" \ |
| /* DAD also sets quit_on_reply, */ \ |
| /* advert also sets unsolicited: */ \ |
| "\0" "=1:Df:AU", \ |
| &count, &str_timeout, &device, &source \ |
| ); |
| |
| struct globals { |
| struct in_addr src; |
| struct in_addr dst; |
| struct sockaddr_ll me; |
| struct sockaddr_ll he; |
| |
| int count; // = -1; |
| unsigned last; |
| unsigned timeout_us; |
| unsigned start; |
| |
| unsigned sent; |
| unsigned brd_sent; |
| unsigned received; |
| unsigned brd_recv; |
| unsigned req_recv; |
| |
| /* should be in main(), but are here to reduce stack use: */ |
| struct ifreq ifr; |
| struct sockaddr_in probe_saddr; |
| sigset_t sset; |
| unsigned char packet[4096]; |
| } FIX_ALIASING; |
| #define src (G.src ) |
| #define dst (G.dst ) |
| #define me (G.me ) |
| #define he (G.he ) |
| #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 G (*(struct globals*)bb_common_bufsiz1) |
| #define G (*ptr_to_globals) |
| #define INIT_G() do { \ |
| /*setup_common_bufsiz();*/ \ |
| SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ |
| count = -1; \ |
| } while (0) |
| |
| #define sock_fd 3 |
| |
| 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; |
| |
| 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 = (unsigned char *) (ah + 1); |
| 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 response(s)" |
| " (%u request(s), %u broadcast(s))\n", |
| sent, brd_sent, |
| received, |
| 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 void 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 */ |
| BUILD_BUG_ON(sizeof(struct in_addr) != 4); |
| BUILD_BUG_ON(sizeof(src_ip.s_addr) != 4); |
| |
| /* Filter out wild packets */ |
| if (FROM->sll_pkttype != PACKET_HOST |
| && FROM->sll_pkttype != PACKET_BROADCAST |
| && FROM->sll_pkttype != PACKET_MULTICAST) |
| return; |
| |
| /* Only these types are recognized */ |
| if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY)) |
| return; |
| |
| /* 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; |
| |
| /* 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; |
| } |
| |
| 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; |
| 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; |
| } 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; |
| } |
| if (!(option_mask32 & QUIET)) { |
| int s_printed = 0; |
| |
| //TODO: arping from iputils-s20160308 print upprcase hex in MAC, follow them? |
| printf("%scast re%s from %s [%02x:%02x:%02x:%02x:%02x:%02x]", |
| FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad", |
| ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest", |
| inet_ntoa(src_ip), |
| p[0], p[1], p[2], p[3], p[4], p[5] |
| ); |
| 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)) { |
| unsigned char *pp = p + ah->ar_hln + 4; |
| if (!s_printed) |
| printf(" for"); |
| printf(" [%02x:%02x:%02x:%02x:%02x:%02x]", |
| pp[0], pp[1], pp[2], pp[3], pp[4], pp[5] |
| ); |
| } |
| |
| if (last) { |
| unsigned diff = MONOTONIC_US() - last; |
| printf(" %u.%03ums\n", diff / 1000, diff % 1000); |
| } else { |
| puts(" UNSOLICITED?"); |
| } |
| fflush_all(); |
| } |
| 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; |
| } |
| } |
| |
| 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; |
| char *err_str; |
| |
| INIT_G(); |
| |
| xmove_fd(xsocket(AF_PACKET, SOCK_DGRAM, 0), sock_fd); |
| |
| // If you ever change BB_SUID_DROP to BB_SUID_REQUIRE, |
| // drop suid root privileges here: |
| //xsetuid(getuid()); |
| |
| { |
| unsigned opt; |
| char *str_timeout; |
| |
| opt = GETOPT32(str_timeout, device, source); |
| if (opt & TIMEOUT) |
| timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000; |
| } |
| |
| target = argv[optind]; |
| err_str = xasprintf("interface %s %%s", device); |
| xfunc_error_retval = 2; |
| |
| /*memset(&G.ifr, 0, sizeof(G.ifr)); - zeroed by INIT_G */ |
| strncpy_IFNAMSIZ(G.ifr.ifr_name, device); |
| ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &G.ifr, err_str, "not found"); |
| me.sll_ifindex = G.ifr.ifr_ifindex; |
| |
| xioctl(sock_fd, SIOCGIFFLAGS, (char *) &G.ifr); |
| |
| if (!(G.ifr.ifr_flags & IFF_UP)) { |
| bb_error_msg_and_die(err_str, "is down"); |
| } |
| if (G.ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) { |
| bb_error_msg(err_str, "is not ARPable"); |
| BUILD_BUG_ON(DAD != 2); |
| /* exit 0 if DAD, else exit 2 */ |
| return (~option_mask32 & DAD); |
| } |
| |
| /* 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 probe_saddr;*/ |
| int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0); |
| |
| setsockopt_bindtodevice(probe_fd, device); |
| |
| /*memset(&G.probe_saddr, 0, sizeof(G.probe_saddr)); - zeroed by INIT_G */ |
| G.probe_saddr.sin_family = AF_INET; |
| if (src.s_addr) { |
| /* Check that this is indeed our IP */ |
| G.probe_saddr.sin_addr = src; |
| xbind(probe_fd, (struct sockaddr *) &G.probe_saddr, sizeof(G.probe_saddr)); |
| } else { /* !(option_mask32 & DAD) case */ |
| /* Find IP address on this iface */ |
| G.probe_saddr.sin_port = htons(1025); |
| G.probe_saddr.sin_addr = dst; |
| |
| if (setsockopt_SOL_SOCKET_1(probe_fd, SO_DONTROUTE) != 0) |
| bb_perror_msg("setsockopt(%s)", "SO_DONTROUTE"); |
| xconnect(probe_fd, (struct sockaddr *) &G.probe_saddr, sizeof(G.probe_saddr)); |
| bb_getsockname(probe_fd, (struct sockaddr *) &G.probe_saddr, sizeof(G.probe_saddr)); |
| if (G.probe_saddr.sin_family != AF_INET) |
| bb_simple_error_msg_and_die("no IP address configured"); |
| src = G.probe_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)); |
| |
| bb_getsockname(sock_fd, (struct sockaddr *) &me, sizeof(me)); |
| //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)"); |
| BUILD_BUG_ON(DAD != 2); |
| /* exit 0 if DAD, else exit 2 */ |
| return (~option_mask32 & DAD); |
| } |
| 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 %s", inet_ntoa(dst)); |
| printf(" from %s %s\n", inet_ntoa(src), device); |
| } |
| |
| /*sigemptyset(&G.sset); - zeroed by INIT_G */ |
| sigaddset(&G.sset, SIGALRM); |
| sigaddset(&G.sset, SIGINT); |
| signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish); |
| signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher); |
| |
| /* Send the first packet, arm ALRM */ |
| catcher(); |
| |
| while (1) { |
| struct sockaddr_ll from; |
| socklen_t alen = sizeof(from); |
| int cc; |
| |
| /* Unblock SIGALRM so that the previously called alarm() |
| * can prevent recvfrom from blocking forever in case the |
| * inherited procmask is blocking SIGALRM. |
| */ |
| sigprocmask(SIG_UNBLOCK, &G.sset, NULL); |
| |
| cc = recvfrom(sock_fd, G.packet, sizeof(G.packet), 0, (struct sockaddr *) &from, &alen); |
| |
| /* Don't allow SIGALRMs while we process the reply */ |
| sigprocmask(SIG_BLOCK, &G.sset, NULL); |
| if (cc < 0) { |
| bb_simple_perror_msg("recvfrom"); |
| continue; |
| } |
| recv_pack(G.packet, cc, &from); |
| } |
| } |