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88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "easysock.h"
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void forward_data(int from_fd, int to_fd) {
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int n = 0;
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char* buffer = malloc(3000*sizeof(char));
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while ((n = recv(from_fd, buffer, 3000, 0)) > 0) { // read data from input socket
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send(to_fd, buffer, n, 0); // send data to output socket
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}
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}
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int check_ip_ver(char* address) {
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char buffer[16]; /* 16 chars - 128 bits - is enough to hold an ipv6 address */
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if (inet_pton(AF_INET,address,buffer) == 1) {
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return 4;
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} else if (inet_pton(AF_INET6,address,buffer) == 1) {
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return 6;
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} else {
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return -1;
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}
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}
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int main(int argc,char* argv[]) {
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/* argv[1] = local address
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argv[2] = local port
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argv[3] = remote address
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argv[4] = remote port */
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char* local_addr = argv[1];
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int local_port = strtol(argv[2],NULL,10);
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char* remote_addr = argv[3];
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int remote_port = strtol(argv[4],NULL,10);
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int preferred_local_network = check_ip_ver(local_addr);
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int preferred_remote_network = check_ip_ver(remote_addr);
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printf("Using %d for local\nUsing %d for remote\n",preferred_local_network,preferred_remote_network);
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if ((preferred_local_network == -1) || (preferred_remote_network == -1)) {
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exit(-7);
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}
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char preferred_transport = 'T';
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struct sockaddr addr_struct;
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int server_sock = create_local(preferred_local_network,preferred_transport,local_addr,local_port,&addr_struct);
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int addrlen;
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if (check_ip_ver(local_addr) == 4) {
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addrlen = sizeof(struct sockaddr_in);
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} else if (check_ip_ver(local_addr) == 6) {
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addrlen = sizeof(struct sockaddr_in6);
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} else {
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exit(-7);
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}
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listen(server_sock,50); /* Arbitrary number, change later */
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printf("Listening on %s:%d\n",local_addr,local_port);
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struct sockaddr remote_addr_struct;
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while (1) {
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int from_client = accept(server_sock,&addr_struct,(socklen_t *)&addrlen);
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int to_server = create_remote(preferred_remote_network,preferred_transport,remote_addr,remote_port,&remote_addr_struct);
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printf("Connection established to %s:%d\n",remote_addr,remote_port);
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if (fork() == 0) {
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/* fork returns 0 for a child, so we're in the child's execution
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right now */
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close(server_sock);
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if (fork() == 0) {
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forward_data(from_client,to_server);
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exit(0);
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}
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if (fork() == 0) {
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forward_data(to_server,from_client);
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exit(0);
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}
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exit(0);
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}
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}
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}
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