www.pudn.com > iputils.rar > arping.c
/*
* arping.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Alexey Kuznetsov,
*/
#include
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#include "SNAPSHOT.h"
static void usage(void) __attribute__((noreturn));
int quit_on_reply=0;
char *device="eth0";
int ifindex;
char *source;
struct in_addr src, dst;
char *target;
int dad, unsolicited, advert;
int quiet;
int count=-1;
int timeout;
int unicasting;
int s;
int broadcast_only;
struct sockaddr_ll me;
struct sockaddr_ll he;
struct timeval start, last;
int sent, brd_sent;
int received, brd_recv, req_recv;
#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
((tv1).tv_usec-(tv2).tv_usec)/1000 )
void usage(void)
{
fprintf(stderr,
"Usage: arping [-fqbDUAV] [-c count] [-w timeout] [-I device] [-s source] destination\n"
" -f : quit on first reply\n"
" -q : be quiet\n"
" -b : keep broadcasting, don't go unicast\n"
" -D : duplicate address detection mode\n"
" -U : Unsolicited ARP mode, update your neighbours\n"
" -A : ARP answer mode, update your neighbours\n"
" -V : print version and exit\n"
" -c count : how many packets to send\n"
" -w timeout : how long to wait for a reply\n"
" -I device : which ethernet device to use (eth0)\n"
" -s source : source ip address\n"
" destination : ask for what ip address\n"
);
exit(2);
}
void set_signal(int signo, void (*handler)(void))
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = (void (*)(int))handler;
sa.sa_flags = SA_RESTART;
sigaction(signo, &sa, NULL);
}
int send_pack(int s, struct in_addr src, struct in_addr dst,
struct sockaddr_ll *ME, struct sockaddr_ll *HE)
{
int err;
struct timeval now;
unsigned char buf[256];
struct arphdr *ah = (struct arphdr*)buf;
unsigned char *p = (unsigned char *)(ah+1);
ah->ar_hrd = htons(ME->sll_hatype);
if (ah->ar_hrd == htons(ARPHRD_FDDI))
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 = advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
memcpy(p, &ME->sll_addr, ah->ar_hln);
p+=ME->sll_halen;
memcpy(p, &src, 4);
p+=4;
if (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, 4);
p+=4;
gettimeofday(&now, NULL);
err = sendto(s, buf, p-buf, 0, (struct sockaddr*)HE, sizeof(*HE));
if (err == p-buf) {
last = now;
sent++;
if (!unicasting)
brd_sent++;
}
return err;
}
void finish(void)
{
if (!quiet) {
printf("Sent %d probes (%d broadcast(s))\n", sent, brd_sent);
printf("Received %d response(s)", received);
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);
printf(")");
}
printf("\n");
fflush(stdout);
}
if (dad)
exit(!!received);
if (unsolicited)
exit(0);
exit(!received);
}
void catcher(void)
{
struct timeval tv;
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 && unsolicited)
finish();
}
alarm(1);
}
void print_hex(unsigned char *p, int len)
{
int i;
for (i=0; isll_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 (!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 =
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 (!quiet) {
int s_printed = 0;
printf("%s ", FROM->sll_pkttype==PACKET_HOST ? "Unicast" : "Broadcast");
printf("%s from ", ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request");
printf("%s [", inet_ntoa(src_ip));
print_hex(p, ah->ar_hln);
printf("] ");
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("[");
print_hex(p+ah->ar_hln+4, ah->ar_hln);
printf("]");
}
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 (quit_on_reply)
finish();
if(!broadcast_only) {
memcpy(he.sll_addr, p, me.sll_halen);
unicasting=1;
}
return 1;
}
int
main(int argc, char **argv)
{
int socket_errno;
int ch;
uid_t uid = getuid();
s = socket(PF_PACKET, SOCK_DGRAM, 0);
socket_errno = errno;
setuid(uid);
while ((ch = getopt(argc, argv, "h?bfDUAqc:w:s:I:V")) != EOF) {
switch(ch) {
case 'b':
broadcast_only=1;
break;
case 'D':
dad++;
quit_on_reply=1;
break;
case 'U':
unsolicited++;
break;
case 'A':
advert++;
unsolicited++;
break;
case 'q':
quiet++;
break;
case 'c':
count = atoi(optarg);
break;
case 'w':
timeout = atoi(optarg);
break;
case 'I':
device = optarg;
break;
case 'f':
quit_on_reply=1;
break;
case 's':
source = optarg;
break;
case 'V':
printf("arping utility, iputils-ss%s\n", SNAPSHOT);
exit(0);
case 'h':
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
target = *argv;
if (device == NULL) {
fprintf(stderr, "arping: device (option -I) is required\n");
usage();
}
if (s < 0) {
errno = socket_errno;
perror("arping: socket");
exit(2);
}
if (1) {
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, device, IFNAMSIZ-1);
if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
fprintf(stderr, "arping: unknown iface %s\n", device);
exit(2);
}
ifindex = ifr.ifr_ifindex;
if (ioctl(s, SIOCGIFFLAGS, (char*)&ifr)) {
perror("ioctl(SIOCGIFFLAGS)");
exit(2);
}
if (!(ifr.ifr_flags&IFF_UP)) {
if (!quiet)
printf("Interface \"%s\" is down\n", device);
exit(2);
}
if (ifr.ifr_flags&(IFF_NOARP|IFF_LOOPBACK)) {
if (!quiet)
printf("Interface \"%s\" is not ARPable\n", device);
exit(dad?0:2);
}
}
if (inet_aton(target, &dst) != 1) {
struct hostent *hp;
hp = gethostbyname2(target, AF_INET);
if (!hp) {
fprintf(stderr, "arping: unknown host %s\n", target);
exit(2);
}
memcpy(&dst, hp->h_addr, 4);
}
if (source && inet_aton(source, &src) != 1) {
fprintf(stderr, "arping: invalid source %s\n", source);
exit(2);
}
if (!dad && unsolicited && src.s_addr == 0)
src = dst;
if (!dad || src.s_addr) {
struct sockaddr_in saddr;
int probe_fd = socket(AF_INET, SOCK_DGRAM, 0);
if (probe_fd < 0) {
perror("socket");
exit(2);
}
if (device) {
if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device)+1) == -1)
perror("WARNING: interface is ignored");
}
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) {
perror("bind");
exit(2);
}
} else if (!dad) {
int on = 1;
int 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)
perror("WARNING: setsockopt(SO_DONTROUTE)");
if (connect(probe_fd, (struct sockaddr*)&saddr, sizeof(saddr)) == -1) {
perror("connect");
exit(2);
}
if (getsockname(probe_fd, (struct sockaddr*)&saddr, &alen) == -1) {
perror("getsockname");
exit(2);
}
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) {
perror("bind");
exit(2);
}
if (1) {
int alen = sizeof(me);
if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {
perror("getsockname");
exit(2);
}
}
if (me.sll_halen == 0) {
if (!quiet)
printf("Interface \"%s\" is not ARPable (no ll address)\n", device);
exit(dad?0:2);
}
he = me;
memset(he.sll_addr, -1, he.sll_halen);
if (!quiet) {
printf("ARPING %s ", inet_ntoa(dst));
printf("from %s %s\n", inet_ntoa(src), device ? : "");
}
if (!src.s_addr && !dad) {
fprintf(stderr, "arping: no source address in not-DAD mode\n");
exit(2);
}
set_signal(SIGINT, finish);
set_signal(SIGALRM, catcher);
catcher();
while(1) {
sigset_t sset, osset;
char packet[4096];
struct sockaddr_ll from;
int alen = sizeof(from);
int cc;
if ((cc = recvfrom(s, packet, sizeof(packet), 0,
(struct sockaddr *)&from, &alen)) < 0) {
perror("arping: 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);
}
}