+++ /dev/null
-/*
- pong.c -- ICMP echo reply generator
- Copyright (C) 2013-2017 Guus Sliepen <guus@tinc-vpn.org>
-
- 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.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-*/
-
-#include "../src/system.h"
-
-#include "../src/ethernet.h"
-
-uint8_t mymac[6] = {6, 5, 5, 6, 5, 5};
-
-static ssize_t do_arp(uint8_t *buf, ssize_t len, struct sockaddr_in *in) {
- struct ether_arp arp;
- memcpy(&arp, buf + 14, sizeof(arp));
-
- // Is it a valid ARP request?
- if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP || arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(in->sin_addr.s_addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
- return 0;
- }
-
- // Does it match our address?
- if(memcmp(&in->sin_addr.s_addr, arp.arp_tpa, 4)) {
- return 0;
- }
-
- // Swap addresses
- memcpy(buf, buf + 6, 6);
- memcpy(buf + 6, mymac, 6);
-
- arp.arp_op = htons(ARPOP_REPLY);
- memcpy(arp.arp_tpa, arp.arp_spa, sizeof(arp.arp_tpa));
- memcpy(arp.arp_tha, arp.arp_sha, sizeof(arp.arp_tha));
- memcpy(arp.arp_spa, &in->sin_addr.s_addr, sizeof(in->sin_addr.s_addr));
- memcpy(arp.arp_sha, mymac, 6);
-
- memcpy(buf + 14, &arp, sizeof(arp));
-
- return len;
-}
-
-static ssize_t do_ipv4(uint8_t *buf, ssize_t len, struct sockaddr_in *in) {
- struct ip ip;
- struct icmp icmp;
-
- // Does it match our address?
- if(memcmp(buf, mymac, 6)) {
- return 0;
- }
-
- memcpy(&ip, buf + 14, sizeof(ip));
-
- if(memcmp(&ip.ip_dst, &in->sin_addr.s_addr, 4)) {
- return 0;
- }
-
- // Is it an ICMP echo request?
- if(ip.ip_p != IPPROTO_ICMP) {
- return 0;
- }
-
- memcpy(&icmp, buf + 14 + sizeof(ip), sizeof(icmp));
-
- if(icmp.icmp_type != ICMP_ECHO) {
- return 0;
- }
-
- // Return an echo reply
- memcpy(buf, buf + 6, 6);
- memcpy(buf + 6, mymac, 6);
-
- ip.ip_dst = ip.ip_src;
- memcpy(&ip.ip_src, &in->sin_addr.s_addr, 4);
-
- icmp.icmp_type = ICMP_ECHOREPLY;
-
- memcpy(buf + 14, &ip, sizeof(ip));
- memcpy(buf + 14 + sizeof(ip), &icmp, sizeof(icmp));
-
- return len;
-}
-
-static ssize_t do_ipv6(uint8_t *buf, ssize_t len, struct sockaddr_in6 *in) {
- return 0;
-}
-
-int main(int argc, char *argv[]) {
- if(argc != 4) {
- fprintf(stderr, "Usage: %s <multicast address> <port> <ping address>\n", argv[0]);
- return 1;
- }
-
- struct addrinfo hints = {}, *ai = NULL;
- hints.ai_socktype = SOCK_DGRAM;
- hints.ai_flags = AI_ADDRCONFIG;
-
- errno = ENOENT;
-
- if(getaddrinfo(argv[1], argv[2], &hints, &ai) || !ai) {
- fprintf(stderr, "Could not resolve %s port %s: %s\n", argv[1], argv[2], strerror(errno));
- return 1;
- }
-
- int fd;
- fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
-
- if(!fd) {
- fprintf(stderr, "Could not create socket: %s\n", strerror(errno));
- return 1;
- }
-
- static const int one = 1;
- setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof(one));
-
- if(bind(fd, ai->ai_addr, ai->ai_addrlen)) {
- fprintf(stderr, "Could not bind socket: %s\n", strerror(errno));
- return 1;
- }
-
- switch(ai->ai_family) {
- case AF_INET: {
- struct ip_mreq mreq;
- struct sockaddr_in in;
- memcpy(&in, ai->ai_addr, sizeof(in));
- mreq.imr_multiaddr.s_addr = in.sin_addr.s_addr;
- mreq.imr_interface.s_addr = htonl(INADDR_ANY);
-
- if(setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&mreq, sizeof(mreq))) {
- fprintf(stderr, "Cannot join multicast group: %s\n", strerror(errno));
- return 1;
- }
-
-#ifdef IP_MULTICAST_LOOP
- setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, (const void *)&one, sizeof(one));
-#endif
- }
- break;
-
-#ifdef IPV6_JOIN_GROUP
-
- case AF_INET6: {
- struct ipv6_mreq mreq;
- struct sockaddr_in6 in6;
- memcpy(&in6, ai->ai_addr, sizeof(in6));
- memcpy(&mreq.ipv6mr_multiaddr, &in6.sin6_addr, sizeof(mreq.ipv6mr_multiaddr));
- mreq.ipv6mr_interface = in6.sin6_scope_id;
-
- if(setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, (void *)&mreq, sizeof(mreq))) {
- fprintf(stderr, "Cannot join multicast group: %s\n", strerror(errno));
- return 1;
- }
-
-#ifdef IPV6_MULTICAST_LOOP
- setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (const void *)&one, sizeof(one));
-#endif
- }
- break;
-#endif
-
- default:
- fprintf(stderr, "Multicast for address family %x unsupported\n", ai->ai_family);
- return 1;
- }
-
- errno = ENOENT;
- struct addrinfo *ai2 = NULL;
-
- if(getaddrinfo(argv[3], NULL, &hints, &ai2) || !ai2) {
- fprintf(stderr, "Could not resolve %s: %s\n", argv[3], strerror(errno));
- return 1;
- }
-
- while(true) {
- uint8_t buf[10000];
- struct sockaddr src;
- socklen_t srclen;
- ssize_t len = recvfrom(fd, buf, sizeof(buf), 0, &src, &srclen);
-
- if(len <= 0) {
- break;
- }
-
- // Ignore short packets.
- if(len < 14) {
- continue;
- }
-
- uint16_t type = buf[12] << 8 | buf[13];
-
- if(ai2->ai_family == AF_INET && type == ETH_P_IP) {
- len = do_ipv4(buf, len, (struct sockaddr_in *)ai2->ai_addr);
- } else if(ai2->ai_family == AF_INET && type == ETH_P_ARP) {
- len = do_arp(buf, len, (struct sockaddr_in *)ai2->ai_addr);
- } else if(ai2->ai_family == AF_INET6 && type == ETH_P_IPV6) {
- len = do_ipv6(buf, len, (struct sockaddr_in6 *)ai2->ai_addr);
- } else {
- continue;
- }
-
- if(len > 0) {
- sendto(fd, buf, len, 0, ai->ai_addr, ai->ai_addrlen);
- }
- }
-
- return 0;
-}
projects / tinc / commitdiff