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- /* 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);
- }
- }
- 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;
- xbind(p_fd, (struct sockaddr*)&saddr, sizeof(saddr));
- } else {
- uint32_t oip;
- saddr.sin_port = htons(1025);
- saddr.sin_addr = dest_addr;
- xconnect(p_fd, (struct sockaddr *) &saddr, sizeof(saddr));
- 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);
- xbind(TT.sockfd, (struct sockaddr *)&src_pk, sizeof(src_pk));
- 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);
- }
- }
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