/* arping - send ARP REQUEST to a neighbour host.
*
* Copyright 2013 Sandeep Sharma <sandeep.jack2756@gmail.com>
* Copyright 2013 Kyungwan Han <asura321@gmail.com>
*
* No Standard.
USE_ARPING(NEWTOY(arping, "<1>1s:I:w#<0c#<0AUDbqf[+AU][+Df]", TOYFLAG_USR|TOYFLAG_SBIN))
config ARPING
bool "arping"
default n
help
usage: arping [-fqbDUA] [-c CNT] [-w TIMEOUT] [-I IFACE] [-s SRC_IP] DST_IP
Send ARP requests/replies
-f Quit on first ARP reply
-q Quiet
-b Keep broadcasting, don't go unicast
-D Duplicated address detection mode
-U Unsolicited ARP mode, update your neighbors
-A ARP answer mode, update your neighbors
-c N Stop after sending N ARP requests
-w TIMEOUT Time to wait for ARP reply, seconds
-I IFACE Interface to use (default eth0)
-s SRC_IP Sender IP address
DST_IP Target IP address
*/
#define FOR_arping
#include "toys.h"
#include <netinet/ether.h>
#include <netpacket/packet.h>
GLOBALS(
long count;
unsigned long time_out;
char *iface;
char *src_ip;
int sockfd;
unsigned long start, end;
unsigned sent_at, sent_nr, rcvd_nr, brd_sent, rcvd_req, brd_rcv,
unicast_flag;
)
struct sockaddr_ll src_pk, dst_pk;
struct in_addr src_addr, dest_addr;
extern void *mempcpy(void *dest, const void *src, size_t n);
// Gets information of INTERFACE and updates IFINDEX, MAC and IP.
static void get_interface(char *interface, int *ifindex, uint32_t *oip,
uint8_t *mac)
{
struct ifreq req;
struct sockaddr_in *ip;
int fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
req.ifr_addr.sa_family = AF_INET;
xstrncpy(req.ifr_name, interface, IFNAMSIZ);
req.ifr_name[IFNAMSIZ-1] = '\0';
xioctl(fd, SIOCGIFFLAGS, &req);
if (!(req.ifr_flags & IFF_UP)) return;
if (oip) {
xioctl(fd, SIOCGIFADDR, &req);
ip = (struct sockaddr_in*) &req.ifr_addr;
*oip = ntohl(ip->sin_addr.s_addr);
}
if (ifindex) {
xioctl(fd, SIOCGIFINDEX, &req);
*ifindex = req.ifr_ifindex;
}
if (mac) {
xioctl(fd, SIOCGIFHWADDR, &req);
memcpy(mac, req.ifr_hwaddr.sa_data, 6);
}
xclose(fd);
}
// SIGINT handler, Print Number of Packets send or receive details.
static void done(int sig)
{
if (!(toys.optflags & FLAG_q)) {
xprintf("Sent %u probe(s) (%u broadcast(s))\n", TT.sent_nr, TT.brd_sent);
xprintf("Received %u repl%s (%u request(s), %u broadcast(s))\n",
TT.rcvd_nr, TT.rcvd_nr == 1 ? "y":"ies", TT.rcvd_req, TT.brd_rcv);
}
if (toys.optflags & FLAG_D) exit(!!TT.rcvd_nr);
//In -U mode, No reply is expected.
if (toys.optflags & FLAG_U) exit(EXIT_SUCCESS);
exit(!TT.rcvd_nr);
}
// Create and Send Packet
static void send_packet()
{
int ret;
unsigned char sbuf[256] = {0,};
struct arphdr *arp_h = (struct arphdr *) sbuf;
unsigned char *ptr = (unsigned char *)(arp_h + 1);
arp_h->ar_hrd = htons(ARPHRD_ETHER);
arp_h->ar_pro = htons(ETH_P_IP);
arp_h->ar_hln = src_pk.sll_halen;
arp_h->ar_pln = 4;
arp_h->ar_op = (toys.optflags & FLAG_A) ? htons(ARPOP_REPLY)
: htons(ARPOP_REQUEST);
ptr = mempcpy(ptr, &src_pk.sll_addr, src_pk.sll_halen);
ptr = mempcpy(ptr, &src_addr, 4);
ptr = mempcpy(ptr,
(toys.optflags & FLAG_A) ? &src_pk.sll_addr : &dst_pk.sll_addr,
src_pk.sll_halen);
ptr = mempcpy(ptr, &dest_addr, 4);
ret = sendto(TT.sockfd, sbuf, ptr - sbuf, 0,
(struct sockaddr *)&dst_pk, sizeof(dst_pk));
if (ret == ptr - sbuf) {
struct timeval tval;
gettimeofday(&tval, NULL);
TT.sent_at = tval.tv_sec * 1000000ULL + tval.tv_usec;
TT.sent_nr++;
if (!TT.unicast_flag) TT.brd_sent++;
}
}
// Receive Packet and filter with valid checks.
static void recv_from(struct sockaddr_ll *from, int *recv_len)
{
struct in_addr s_ip, d_ip;
struct arphdr *arp_hdr = (struct arphdr *)toybuf;
unsigned char *p = (unsigned char *)(arp_hdr + 1);
if (arp_hdr->ar_op != htons(ARPOP_REQUEST) &&
arp_hdr->ar_op != htons(ARPOP_REPLY)) return;
if (from->sll_pkttype != PACKET_HOST && from->sll_pkttype != PACKET_BROADCAST
&& from->sll_pkttype != PACKET_MULTICAST) return;
if (arp_hdr->ar_pro != htons(ETH_P_IP) || (arp_hdr->ar_pln != 4)
|| (arp_hdr->ar_hln != src_pk.sll_halen)
|| (*recv_len < (int)(sizeof(*arp_hdr) + 2 * (4 + arp_hdr->ar_hln))))
return;
memcpy(&s_ip.s_addr, p + arp_hdr->ar_hln, 4);
memcpy(&d_ip.s_addr, p + arp_hdr->ar_hln + 4 + arp_hdr->ar_hln, 4);
if (dest_addr.s_addr != s_ip.s_addr) return;
if (toys.optflags & FLAG_D) {
if (src_addr.s_addr && src_addr.s_addr != d_ip.s_addr) return;
if (!memcmp(p, &src_pk.sll_addr, src_pk.sll_halen)) return;
} else if (src_addr.s_addr != d_ip.s_addr ) return;
if (!(toys.optflags & FLAG_q)) {
printf("%scast re%s from %s [%s]",
from->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
arp_hdr->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
inet_ntoa(s_ip), ether_ntoa((struct ether_addr *) p));
if (TT.sent_at) {
unsigned delta;
struct timeval tval;
gettimeofday(&tval, NULL);
delta = (tval.tv_sec * 1000000ULL + (tval.tv_usec)) - TT.sent_at;
xprintf(" %u.%03ums\n", delta / 1000, delta % 1000);
xflush();
}
}
TT.rcvd_nr++;
if (from->sll_pkttype != PACKET_HOST) TT.brd_rcv++;
if (arp_hdr->ar_op == htons(ARPOP_REQUEST)) TT.rcvd_req++;
if (toys.optflags & FLAG_f) done(0);
if (!(toys.optflags & FLAG_b)) {
memcpy(dst_pk.sll_addr, p, src_pk.sll_halen);
TT.unicast_flag = 1;
}
}
// Alarm signal Handle, send packets in one second interval.
static void send_signal(int sig)
{
struct timeval start;
gettimeofday(&start, NULL);
if (!TT.start)
TT.end = TT.start = start.tv_sec * 1000 + start.tv_usec / 1000;
else TT.end = start.tv_sec*1000 + start.tv_usec / 1000;
if (toys.optflags & FLAG_c) {
if (!TT.count) done(0);
TT.count--;
}
if ((toys.optflags & FLAG_w) && ((TT.end - TT.start) >
((TT.time_out)*1000))) done(0);
send_packet();
alarm(1);
}
void arping_main(void)
{
struct ifreq ifr;
struct sockaddr_ll from;
socklen_t len;
int if_index, recv_len;
if (!(toys.optflags & FLAG_I)) TT.iface = "eth0";
TT.sockfd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
memset(&ifr, 0, sizeof(ifr));
xstrncpy(ifr.ifr_name, TT.iface, IFNAMSIZ);
get_interface(TT.iface, &if_index, NULL, NULL);
src_pk.sll_ifindex = if_index;
xioctl(TT.sockfd, SIOCGIFFLAGS, (char*)&ifr);
if (!(ifr.ifr_flags & IFF_UP) && !(toys.optflags & FLAG_q))
error_exit("Interface \"%s\" is down", TT.iface);
if ((ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK))
&& !(toys.optflags & FLAG_q)) {
xprintf("Interface \"%s\" is not ARPable\n", TT.iface);
toys.exitval = (toys.optflags & FLAG_D) ? 0 : 2;
return;
}
if (!inet_aton(*toys.optargs, &dest_addr)) {
struct hostent *hp = gethostbyname2(*toys.optargs, AF_INET);
if (!hp) perror_exit("bad address '%s'", *toys.optargs);
memcpy(&dest_addr, hp->h_addr, 4);
}
if ((toys.optflags & FLAG_s) && !(inet_aton(TT.src_ip, &src_addr)))
perror_exit("invalid source address '%s'",TT.src_ip);
if (!(toys.optflags & FLAG_D) && (toys.optflags & FLAG_U)
&& !src_addr.s_addr) src_addr = dest_addr;
if (!(toys.optflags & FLAG_D) || src_addr.s_addr) {
struct sockaddr_in saddr;
int p_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
if (setsockopt(p_fd, SOL_SOCKET, SO_BINDTODEVICE, TT.iface,
strlen(TT.iface))) perror_exit("setsockopt");
memset(&saddr, 0, sizeof(saddr));
saddr.sin_family = AF_INET;
if (src_addr.s_addr) {
saddr.sin_addr = src_addr;
if (bind(p_fd, (struct sockaddr*)&saddr, sizeof(saddr)))
perror_exit("bind");
} else {
uint32_t oip;
saddr.sin_port = htons(1025);
saddr.sin_addr = dest_addr;
if (connect(p_fd, (struct sockaddr *) &saddr, sizeof(saddr)))
perror_exit("cannot connect to remote host");
get_interface(TT.iface, NULL, &oip, NULL);
src_addr.s_addr = htonl(oip);
}
xclose(p_fd);
}
src_pk.sll_family = AF_PACKET;
src_pk.sll_protocol = htons(ETH_P_ARP);
if (bind(TT.sockfd, (struct sockaddr *)&src_pk, sizeof(src_pk)))
perror_exit("bind");
socklen_t alen = sizeof(src_pk);
getsockname(TT.sockfd, (struct sockaddr *)&src_pk, &alen);
if (!src_pk.sll_halen) {
perror_msg("src is not arpable");
toys.exitval = (toys.optflags & FLAG_D) ? 0 : 2;
return;
}
if (!(toys.optflags & FLAG_q)) {
xprintf("ARPING to %s", inet_ntoa(dest_addr));
xprintf(" from %s via %s\n", inet_ntoa(src_addr), TT.iface);
}
dst_pk = src_pk;
//First packet always broadcasts.
memset(dst_pk.sll_addr, -1, dst_pk.sll_halen);
signal(SIGINT, done);
signal(SIGALRM, send_signal);
send_signal(0); // Send first Broadcast message.
while (1) {
len = sizeof(from);
recv_len = recvfrom(TT.sockfd, toybuf, 4096, 0,
(struct sockaddr *)&from, &len);
if (recv_len < 0) continue;
recv_from(&from, &recv_len);
}
}