mirror of
https://github.com/sheumann/hush.git
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457 lines
10 KiB
C
457 lines
10 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* arping.c - Ping hosts by ARP requests/replies
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*
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* Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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* Busybox port: Nick Fedchik <nick@fedchik.org.ua>
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*/
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#include <sys/ioctl.h>
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#include <signal.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <net/if.h>
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#include <netinet/ether.h>
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#include <netpacket/packet.h>
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#include "busybox.h"
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static struct in_addr src;
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static struct in_addr dst;
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static struct sockaddr_ll me;
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static struct sockaddr_ll he;
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static struct timeval last;
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enum cfg_e {
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dad = 1,
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unsolicited = 2,
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advert = 4,
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quiet = 8,
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quit_on_reply = 16,
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broadcast_only = 32,
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unicasting = 64
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};
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static int cfg;
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static int s;
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static int count = -1;
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static int timeout;
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static int sent;
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static int brd_sent;
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static int received;
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static int brd_recv;
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static int req_recv;
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#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
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((tv1).tv_usec-(tv2).tv_usec)/1000 )
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static int send_pack(int sock, struct in_addr *src_addr,
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struct in_addr *dst_addr, struct sockaddr_ll *ME,
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struct sockaddr_ll *HE)
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{
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int err;
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struct timeval now;
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RESERVE_CONFIG_UBUFFER(buf, 256);
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struct arphdr *ah = (struct arphdr *) buf;
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unsigned char *p = (unsigned char *) (ah + 1);
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ah->ar_hrd = htons(ME->sll_hatype);
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ah->ar_hrd = htons(ARPHRD_ETHER);
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ah->ar_pro = htons(ETH_P_IP);
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ah->ar_hln = ME->sll_halen;
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ah->ar_pln = 4;
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ah->ar_op = cfg&advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
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memcpy(p, &ME->sll_addr, ah->ar_hln);
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p += ME->sll_halen;
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memcpy(p, src_addr, 4);
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p += 4;
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if (cfg&advert)
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memcpy(p, &ME->sll_addr, ah->ar_hln);
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else
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memcpy(p, &HE->sll_addr, ah->ar_hln);
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p += ah->ar_hln;
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memcpy(p, dst_addr, 4);
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p += 4;
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gettimeofday(&now, NULL);
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err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
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if (err == p - buf) {
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last = now;
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sent++;
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if (!(cfg&unicasting))
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brd_sent++;
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}
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RELEASE_CONFIG_BUFFER(buf);
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return err;
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}
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static void finish(void)
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{
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if (!(cfg&quiet)) {
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printf("Sent %d probes (%d broadcast(s))\n"
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"Received %d repl%s",
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sent, brd_sent,
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received, (received > 1) ? "ies" : "y");
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if (brd_recv || req_recv) {
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printf(" (");
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if (req_recv)
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printf("%d request(s)", req_recv);
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if (brd_recv)
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printf("%s%d broadcast(s)", req_recv ? ", " : "", brd_recv);
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putchar(')');
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}
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putchar('\n');
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fflush(stdout);
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}
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if (cfg&dad)
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exit(!!received);
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if (cfg&unsolicited)
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exit(0);
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exit(!received);
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}
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static void catcher(void)
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{
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struct timeval tv;
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static struct timeval start;
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gettimeofday(&tv, NULL);
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if (start.tv_sec == 0)
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start = tv;
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if (count-- == 0
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|| (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500))
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finish();
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if (last.tv_sec == 0 || MS_TDIFF(tv, last) > 500) {
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send_pack(s, &src, &dst, &me, &he);
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if (count == 0 && cfg&unsolicited)
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finish();
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}
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alarm(1);
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}
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static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
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{
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struct arphdr *ah = (struct arphdr *) buf;
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unsigned char *p = (unsigned char *) (ah + 1);
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struct in_addr src_ip, dst_ip;
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/* Filter out wild packets */
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if (FROM->sll_pkttype != PACKET_HOST &&
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FROM->sll_pkttype != PACKET_BROADCAST &&
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FROM->sll_pkttype != PACKET_MULTICAST)
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return 0;
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/* Only these types are recognised */
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if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
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return 0;
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/* ARPHRD check and this darned FDDI hack here :-( */
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if (ah->ar_hrd != htons(FROM->sll_hatype) &&
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(FROM->sll_hatype != ARPHRD_FDDI
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|| ah->ar_hrd != htons(ARPHRD_ETHER)))
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return 0;
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/* Protocol must be IP. */
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if (ah->ar_pro != htons(ETH_P_IP))
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return 0;
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if (ah->ar_pln != 4)
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return 0;
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if (ah->ar_hln != me.sll_halen)
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return 0;
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if (len < sizeof(*ah) + 2 * (4 + ah->ar_hln))
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return 0;
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memcpy(&src_ip, p + ah->ar_hln, 4);
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memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
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if (!(cfg&dad)) {
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if (src_ip.s_addr != dst.s_addr)
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return 0;
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if (src.s_addr != dst_ip.s_addr)
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return 0;
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if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))
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return 0;
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} else {
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/* DAD packet was:
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src_ip = 0 (or some src)
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src_hw = ME
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dst_ip = tested address
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dst_hw = <unspec>
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We fail, if receive request/reply with:
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src_ip = tested_address
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src_hw != ME
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if src_ip in request was not zero, check
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also that it matches to dst_ip, otherwise
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dst_ip/dst_hw do not matter.
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*/
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if (src_ip.s_addr != dst.s_addr)
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return 0;
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if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
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return 0;
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if (src.s_addr && src.s_addr != dst_ip.s_addr)
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return 0;
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}
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if (!(cfg&quiet)) {
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int s_printed = 0;
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struct timeval tv;
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gettimeofday(&tv, NULL);
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printf("%s %s from %s [%s]",
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FROM->sll_pkttype == PACKET_HOST ? "Unicast" : "Broadcast",
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ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request",
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inet_ntoa(src_ip),
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ether_ntoa((struct ether_addr *) p));
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if (dst_ip.s_addr != src.s_addr) {
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printf("for %s ", inet_ntoa(dst_ip));
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s_printed = 1;
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}
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if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
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if (!s_printed)
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printf("for ");
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printf("[%s]",
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ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
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}
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if (last.tv_sec) {
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long usecs = (tv.tv_sec - last.tv_sec) * 1000000 +
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tv.tv_usec - last.tv_usec;
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long msecs = (usecs + 500) / 1000;
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usecs -= msecs * 1000 - 500;
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printf(" %ld.%03ldms\n", msecs, usecs);
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} else {
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printf(" UNSOLICITED?\n");
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}
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fflush(stdout);
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}
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received++;
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if (FROM->sll_pkttype != PACKET_HOST)
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brd_recv++;
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if (ah->ar_op == htons(ARPOP_REQUEST))
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req_recv++;
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if (cfg&quit_on_reply)
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finish();
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if (!(cfg&broadcast_only)) {
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memcpy(he.sll_addr, p, me.sll_halen);
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cfg |= unicasting;
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}
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return 1;
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}
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int arping_main(int argc, char **argv)
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{
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char *device = "eth0";
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int ifindex;
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char *source = NULL;
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char *target;
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s = socket(PF_PACKET, SOCK_DGRAM, 0);
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ifindex = errno;
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setuid(getuid());
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{
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unsigned long opt;
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char *_count, *_timeout, *_device;
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/* Dad also sets quit_on_reply.
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* Advert also sets unsolicited.
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*/
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bb_opt_complementally = "Df:AU";
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opt = bb_getopt_ulflags(argc, argv, "DUAqfbc:w:i:s:",
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&_count, &_timeout, &_device);
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cfg |= opt & 63; /* set respective flags */
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if (opt & 64) /* count */
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count = atoi(_count);
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if (opt & 128) /* timeout */
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timeout = atoi(_timeout);
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if (opt & 256) { /* interface */
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if (strlen(_device) > IF_NAMESIZE) {
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bb_error_msg_and_die("Interface name `%s' must be less than %d",
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_device, IF_NAMESIZE);
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}
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device = _device;
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}
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if (opt & 512) /* source */
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source = optarg;
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}
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argc -= optind;
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argv += optind;
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if (argc != 1)
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bb_show_usage();
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target = *argv;
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if (s < 0) {
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bb_default_error_retval = ifindex;
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bb_perror_msg_and_die("socket");
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}
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bb_default_error_retval = 2;
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{
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struct ifreq ifr;
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memset(&ifr, 0, sizeof(ifr));
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strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
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if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
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bb_error_msg_and_die("Interface %s not found", device);
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}
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ifindex = ifr.ifr_ifindex;
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if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
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bb_error_msg_and_die("SIOCGIFFLAGS");
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}
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if (!(ifr.ifr_flags & IFF_UP)) {
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bb_error_msg_and_die("Interface %s is down", device);
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}
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if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
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bb_error_msg("Interface %s is not ARPable", device);
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exit(cfg&dad ? 0 : 2);
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}
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}
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if (!inet_aton(target, &dst)) {
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struct hostent *hp;
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hp = gethostbyname2(target, AF_INET);
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if (!hp) {
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bb_error_msg_and_die("invalid or unknown target %s", target);
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}
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memcpy(&dst, hp->h_addr, 4);
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}
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if (source && !inet_aton(source, &src)) {
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bb_error_msg_and_die("invalid source address %s", source);
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}
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if (!(cfg&dad) && cfg&unsolicited && src.s_addr == 0)
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src = dst;
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if (!(cfg&dad) || src.s_addr) {
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struct sockaddr_in saddr;
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int probe_fd = socket(AF_INET, SOCK_DGRAM, 0); /* maybe use bb_xsocket? */
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if (probe_fd < 0) {
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bb_error_msg_and_die("socket");
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}
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if (device) {
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if (setsockopt
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(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device,
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strlen(device) + 1) == -1)
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bb_error_msg("WARNING: interface %s is ignored", device);
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}
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memset(&saddr, 0, sizeof(saddr));
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saddr.sin_family = AF_INET;
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if (src.s_addr) {
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saddr.sin_addr = src;
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if (bind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) == -1) {
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bb_error_msg_and_die("bind");
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}
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} else if (!(cfg&dad)) {
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int on = 1;
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socklen_t alen = sizeof(saddr);
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saddr.sin_port = htons(1025);
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saddr.sin_addr = dst;
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if (setsockopt
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(probe_fd, SOL_SOCKET, SO_DONTROUTE, (char *) &on,
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sizeof(on)) == -1)
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bb_perror_msg("WARNING: setsockopt(SO_DONTROUTE)");
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if (connect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr))
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== -1) {
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bb_error_msg_and_die("connect");
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}
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if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) ==
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-1) {
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bb_error_msg_and_die("getsockname");
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}
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src = saddr.sin_addr;
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}
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close(probe_fd);
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};
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me.sll_family = AF_PACKET;
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me.sll_ifindex = ifindex;
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me.sll_protocol = htons(ETH_P_ARP);
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if (bind(s, (struct sockaddr *) &me, sizeof(me)) == -1) {
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bb_error_msg_and_die("bind");
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}
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{
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socklen_t alen = sizeof(me);
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if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
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bb_error_msg_and_die("getsockname");
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}
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}
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if (me.sll_halen == 0) {
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bb_error_msg("Interface \"%s\" is not ARPable (no ll address)", device);
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exit(cfg&dad ? 0 : 2);
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}
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he = me;
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memset(he.sll_addr, -1, he.sll_halen);
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if (!(cfg&quiet)) {
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printf("ARPING to %s from %s via %s\n",
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inet_ntoa(dst), inet_ntoa(src),
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device ? device : "unknown");
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}
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if (!src.s_addr && !(cfg&dad)) {
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bb_error_msg_and_die("no src address in the non-DAD mode");
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}
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_flags = SA_RESTART;
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sa.sa_handler = (void (*)(int)) finish;
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sigaction(SIGINT, &sa, NULL);
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sa.sa_handler = (void (*)(int)) catcher;
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sigaction(SIGALRM, &sa, NULL);
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}
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catcher();
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while (1) {
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sigset_t sset, osset;
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RESERVE_CONFIG_UBUFFER(packet, 4096);
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struct sockaddr_ll from;
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socklen_t alen = sizeof(from);
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int cc;
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if ((cc = recvfrom(s, packet, 4096, 0,
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(struct sockaddr *) &from, &alen)) < 0) {
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perror("recvfrom");
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continue;
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}
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sigemptyset(&sset);
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sigaddset(&sset, SIGALRM);
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sigaddset(&sset, SIGINT);
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sigprocmask(SIG_BLOCK, &sset, &osset);
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recv_pack(packet, cc, &from);
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sigprocmask(SIG_SETMASK, &osset, NULL);
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RELEASE_CONFIG_BUFFER(packet);
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}
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}
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