diff options
Diffstat (limited to 'networking/arping.c')
| -rw-r--r-- | networking/arping.c | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/networking/arping.c b/networking/arping.c new file mode 100644 index 000000000..2d92bf4be --- /dev/null +++ b/networking/arping.c @@ -0,0 +1,446 @@ +/* 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 unsigned count = UINT_MAX; +static unsigned 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 opt; + char *_count, *_timeout; + + /* Dad also sets quit_on_reply. + * Advert also sets unsolicited. + */ + opt_complementary = "Df:AU"; + opt = getopt32(argc, argv, "DUAqfbc:w:i:s:", + &_count, &_timeout, &device, &source); + cfg |= opt & 0x3f; /* set respective flags */ + if (opt & 0x40) /* -c: count */ + count = xatou(_count); + if (opt & 0x80) /* -w: timeout */ + timeout = xatoul_range(_timeout, 0, INT_MAX/2000); + 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)) { + static const 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); + } +} |