tcprpf-server.c - net/tcprpf - Rivoreo Source Code Repositories

 /*
  * Copyright 2015-2017 Rivoreo
  *
  * 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.
  */

 #include "common.h"
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include "syncrw.h"
 #include <signal.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <errno.h>

 extern int forward(int, int);

 static void signal_handler(int sig) {
 	if(sig != SIGCHLD) return;
 	//while(wait(NULL) < 0) {
 	while(waitpid(-1, NULL, WNOHANG) < 0) {
 		if(errno == EINTR) continue;
 		perror("waitpid");
 		return;
 	}
 }

 int main(int argc, char **argv) {
 	// TODO: Use getopt(3) to parse unlimited number of forward listen ports.
 	// TODO: Add support for bind to a specified address instead of INADDR_ANY for each listen.

 	if(argc != 3) {
 		fprintf(stderr, "Usage: %s <forward-listen-port> <data-listen-port>\n", argv[0]);
 		return -1;
 	}

 	struct sigaction act = { .sa_handler = SIG_IGN };
 	if(sigaction(SIGPIPE, &act, NULL) < 0) {
 		perror("sigaction");
 		return 1;
 	}
 	act.sa_handler = signal_handler;
 	sigaction(SIGCHLD, &act, NULL);

 	int forward_port = atoi(argv[1]);
 	int data_port = atoi(argv[2]);
 	if(forward_port < 1 || data_port < 1) {
 		fprintf(stderr, "%s: Port number must be greater than 0\n", argv[0]);
 		return -1;
 	}

 	const char *name = strchr(argv[0], '/');
 	if(name) name++; else name = argv[0];
 	fprintf(stderr, "TCP Reverse Port Forwarding Server - %s\n"
 		RIVOREO_COPYRIGHT_NOTICE "\n"
 		LICENSE_INFORMATION "\n\n", name);

 	int data_socket = socket(AF_INET, SOCK_STREAM, 0);
 	int forward_socket = socket(AF_INET, SOCK_STREAM, 0);
 	if(data_socket == -1 || forward_socket == -1) {
 		perror("socket");
 		return 1;
 	}
 	int reuseaddr = 1;
 	if(setsockopt(data_socket, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof reuseaddr) < 0) perror("setsockopt");
 	if(setsockopt(forward_socket, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof reuseaddr) < 0) perror("setsockopt");

 	struct sockaddr_in data_listen_addr = {
 		.sin_family = AF_INET,
 		.sin_addr.s_addr = htonl(INADDR_ANY),
 		.sin_port = htons(data_port)
 	};
 	while(bind(data_socket, (struct sockaddr *)&data_listen_addr, sizeof data_listen_addr) < 0) {
 		if(errno == EAGAIN || errno == EINTR) continue;
 		perror("bind");
 		return 1;
 	}

 	struct sockaddr_in forward_listen_addr = {
 		.sin_family = AF_INET,
 		.sin_addr.s_addr = htonl(INADDR_ANY),
 		.sin_port = htons(forward_port)
 	};
 	while(bind(forward_socket, (struct sockaddr *)&forward_listen_addr, sizeof forward_listen_addr) < 0) {
 		if(errno == EAGAIN || errno == EINTR) continue;
 		perror("bind");
 		return 1;
 	}

 	if(listen(data_socket, 1) < 0) {
 		perror("listen");
 		return 1;
 	}

 	if(listen(forward_socket, 100) < 0) {
 		perror("listen");
 		return 1;
 	}

 	fd_set fdset;
 	struct timeval delay_tv;

 	while(1) {
 		struct sockaddr_in data_client_addr;
 		socklen_t data_addr_len = sizeof data_client_addr;
 		int data_c_fd;
 		do {
 			data_c_fd = accept(data_socket, (struct sockaddr *)&data_client_addr, &data_addr_len);
 		} while(data_c_fd == -1 && errno == EINTR);
 		if(data_c_fd == -1) {
 			perror("accept: data");
 			sleep(1);
 			continue;
 		}
 		fprintf(stderr, "connection to data port %d from %s port %d fd %d\n",
 			data_port, inet_ntoa(data_client_addr.sin_addr), ntohs(data_client_addr.sin_port), data_c_fd);

 		FD_ZERO(&fdset);
 		FD_SET(forward_socket, &fdset);
 		FD_SET(data_c_fd, &fdset);
 		int max_fd = MAX(forward_socket, data_c_fd);

 		while(1) {
 			fd_set rfdset = fdset;
 			delay_tv.tv_sec = 60;
 			delay_tv.tv_usec = 0;
 			int n = select(max_fd + 1, &rfdset, NULL, NULL, &delay_tv);
 			if(n < 0) {
 				if(errno == EINTR) continue;
 				perror("select");
 				sleep(1);
 				continue;
 			}
 			if(n) {
 				if(FD_ISSET(forward_socket, &rfdset)) {
 					struct sockaddr_in forward_client_addr;
 					socklen_t forward_addr_len = sizeof forward_client_addr;
 					int forward_c_fd;
 					do {
 						forward_c_fd = accept(forward_socket, (struct sockaddr *)&forward_client_addr, &forward_addr_len);
 					} while(forward_c_fd == -1 && errno == EINTR);
 					if(forward_c_fd == -1) {
 						perror("accept: forward");
 						sleep(1);
 						continue;
 					}
 					fprintf(stderr, "connection to forward port %d from %s port %d fd %d\n",
 						forward_port, inet_ntoa(forward_client_addr.sin_addr), ntohs(forward_client_addr.sin_port), data_c_fd);
 					uint16_t packet_type = htons(NEW_CONNECTION);
 					struct new_connection_packet packet;
 					packet.len = htonl(sizeof packet);
 /*
 					if(gettimeofday(&packet.tv, NULL) < 0) {
 						perror("gettimeofday");
 						memset(&packet.tv, 0, sizeof packet.tv);
 					}
 					memcpy(&packet.addr, &forward_client_addr, sizeof forward_client_addr);
 					size_t ped_zero_len = sizeof packet.addr - sizeof forward_client_addr;
 					memset(&packet.addr, 0, ped_zero_len);
 */
 					packet.address = forward_client_addr.sin_addr;
 					packet.port = forward_client_addr.sin_port;
 					if(sync_write(data_c_fd, MAGIC, 4) < 0 || sync_write(data_c_fd, &packet_type, sizeof packet_type) < 0 || sync_write(data_c_fd, &packet, sizeof packet) < 0) {
 						perror("write");
 						break;
 					}

 					pid_t pid = fork();
 					if(pid < 0) {
 						perror("fork");
 						close(forward_c_fd);
 						continue;
 					}
 					if(pid) {
 						//close(data_c_fd);	// Will be closed in end of the outer loop
 						close(forward_c_fd);
 						break;
 					} else {
 						close(data_socket);
 						close(forward_socket);
 						exit(forward(data_c_fd, forward_c_fd) < 0 ? 1 : 0);
 						//_exit(0);
 					}
 				}
 				if(FD_ISSET(data_c_fd, &rfdset)) {
 					char magic[sizeof MAGIC - 1];
 					int s;
 					do {
 						s = read(data_c_fd, magic, sizeof magic);
 					} while(s < 0 && errno == EINTR);
 					if(s < sizeof magic) {
 						if(s) fprintf(stderr, "%s: XXX closing connection due to incomplete packet (received %d byte(s))\n", argv[0], s);
 						break;
 					}
 					if(memcmp(magic, MAGIC, sizeof magic)) {
 						fprintf(stderr, "%s: Protocol mismatch\n", argv[0]);
 						break;
 					}
 					uint16_t packet_type;
 					do {
 						s = read(data_c_fd, &packet_type, sizeof packet_type);
 					} while(s < 0 && errno == EINTR);
 					if(s < sizeof packet_type) {
 						if(s) fprintf(stderr, "%s: XXX closing connection due to incomplete packet (received %d byte)\n", argv[0], s);
 						break;
 					}
 					packet_type = ntohs(packet_type);
 					if(packet_type != KEEP_ALIVE) {
 						fprintf(stderr, "%s: Unknown packet type %hu received from client\n", argv[0], packet_type);
 						break;
 					}
 					fprintf(stderr, "%s: keep alive from client\n", argv[0]);
 				}
 			} else {
 				uint16_t packet_type = htons(KEEP_ALIVE);
 				//uint16_t packet_type = KEEP_ALIVE;
 				if(sync_write(data_c_fd, MAGIC, 4) < 0 || sync_write(data_c_fd, &packet_type, sizeof packet_type) < 0) {
 					perror("write");
 					break;
 				}
 			}
 		}
 		close(data_c_fd);
 	}
 }
	/*
	* Copyright 2015-2017 Rivoreo
	*
	* 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.
	*/

	#include "common.h"
	#include <sys/types.h>
	#include <sys/time.h>
	#include <sys/wait.h>
	#include <sys/socket.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <unistd.h>
	#include "syncrw.h"
	#include <signal.h>
	#include <string.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <errno.h>

	extern int forward(int, int);

	static void signal_handler(int sig) {
	if(sig != SIGCHLD) return;
	//while(wait(NULL) < 0) {
	while(waitpid(-1, NULL, WNOHANG) < 0) {
	if(errno == EINTR) continue;
	perror("waitpid");
	return;
	}
	}

	int main(int argc, char **argv) {
	// TODO: Use getopt(3) to parse unlimited number of forward listen ports.
	// TODO: Add support for bind to a specified address instead of INADDR_ANY for each listen.

	if(argc != 3) {
	fprintf(stderr, "Usage: %s <forward-listen-port> <data-listen-port>\n", argv[0]);
	return -1;
	}

	struct sigaction act = { .sa_handler = SIG_IGN };
	if(sigaction(SIGPIPE, &act, NULL) < 0) {
	perror("sigaction");
	return 1;
	}
	act.sa_handler = signal_handler;
	sigaction(SIGCHLD, &act, NULL);

	int forward_port = atoi(argv[1]);
	int data_port = atoi(argv[2]);
	if(forward_port < 1 \|\| data_port < 1) {
	fprintf(stderr, "%s: Port number must be greater than 0\n", argv[0]);
	return -1;
	}

	const char *name = strchr(argv[0], '/');
	if(name) name++; else name = argv[0];
	fprintf(stderr, "TCP Reverse Port Forwarding Server - %s\n"
	RIVOREO_COPYRIGHT_NOTICE "\n"
	LICENSE_INFORMATION "\n\n", name);

	int data_socket = socket(AF_INET, SOCK_STREAM, 0);
	int forward_socket = socket(AF_INET, SOCK_STREAM, 0);
	if(data_socket == -1 \|\| forward_socket == -1) {
	perror("socket");
	return 1;
	}
	int reuseaddr = 1;
	if(setsockopt(data_socket, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof reuseaddr) < 0) perror("setsockopt");
	if(setsockopt(forward_socket, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof reuseaddr) < 0) perror("setsockopt");

	struct sockaddr_in data_listen_addr = {
	.sin_family = AF_INET,
	.sin_addr.s_addr = htonl(INADDR_ANY),
	.sin_port = htons(data_port)
	};
	while(bind(data_socket, (struct sockaddr *)&data_listen_addr, sizeof data_listen_addr) < 0) {
	if(errno == EAGAIN \|\| errno == EINTR) continue;
	perror("bind");
	return 1;
	}

	struct sockaddr_in forward_listen_addr = {
	.sin_family = AF_INET,
	.sin_addr.s_addr = htonl(INADDR_ANY),
	.sin_port = htons(forward_port)
	};
	while(bind(forward_socket, (struct sockaddr *)&forward_listen_addr, sizeof forward_listen_addr) < 0) {
	if(errno == EAGAIN \|\| errno == EINTR) continue;
	perror("bind");
	return 1;
	}

	if(listen(data_socket, 1) < 0) {
	perror("listen");
	return 1;
	}

	if(listen(forward_socket, 100) < 0) {
	perror("listen");
	return 1;
	}

	fd_set fdset;
	struct timeval delay_tv;

	while(1) {
	struct sockaddr_in data_client_addr;
	socklen_t data_addr_len = sizeof data_client_addr;
	int data_c_fd;
	do {
	data_c_fd = accept(data_socket, (struct sockaddr *)&data_client_addr, &data_addr_len);
	} while(data_c_fd == -1 && errno == EINTR);
	if(data_c_fd == -1) {
	perror("accept: data");
	sleep(1);
	continue;
	}
	fprintf(stderr, "connection to data port %d from %s port %d fd %d\n",
	data_port, inet_ntoa(data_client_addr.sin_addr), ntohs(data_client_addr.sin_port), data_c_fd);

	FD_ZERO(&fdset);
	FD_SET(forward_socket, &fdset);
	FD_SET(data_c_fd, &fdset);
	int max_fd = MAX(forward_socket, data_c_fd);

	while(1) {
	fd_set rfdset = fdset;
	delay_tv.tv_sec = 60;
	delay_tv.tv_usec = 0;
	int n = select(max_fd + 1, &rfdset, NULL, NULL, &delay_tv);
	if(n < 0) {
	if(errno == EINTR) continue;
	perror("select");
	sleep(1);
	continue;
	}
	if(n) {
	if(FD_ISSET(forward_socket, &rfdset)) {
	struct sockaddr_in forward_client_addr;
	socklen_t forward_addr_len = sizeof forward_client_addr;
	int forward_c_fd;
	do {
	forward_c_fd = accept(forward_socket, (struct sockaddr *)&forward_client_addr, &forward_addr_len);
	} while(forward_c_fd == -1 && errno == EINTR);
	if(forward_c_fd == -1) {
	perror("accept: forward");
	sleep(1);
	continue;
	}
	fprintf(stderr, "connection to forward port %d from %s port %d fd %d\n",
	forward_port, inet_ntoa(forward_client_addr.sin_addr), ntohs(forward_client_addr.sin_port), data_c_fd);
	uint16_t packet_type = htons(NEW_CONNECTION);
	struct new_connection_packet packet;
	packet.len = htonl(sizeof packet);
	/*
	if(gettimeofday(&packet.tv, NULL) < 0) {
	perror("gettimeofday");
	memset(&packet.tv, 0, sizeof packet.tv);
	}
	memcpy(&packet.addr, &forward_client_addr, sizeof forward_client_addr);
	size_t ped_zero_len = sizeof packet.addr - sizeof forward_client_addr;
	memset(&packet.addr, 0, ped_zero_len);
	*/
	packet.address = forward_client_addr.sin_addr;
	packet.port = forward_client_addr.sin_port;
	if(sync_write(data_c_fd, MAGIC, 4) < 0 \|\| sync_write(data_c_fd, &packet_type, sizeof packet_type) < 0 \|\| sync_write(data_c_fd, &packet, sizeof packet) < 0) {
	perror("write");
	break;
	}

	pid_t pid = fork();
	if(pid < 0) {
	perror("fork");
	close(forward_c_fd);
	continue;
	}
	if(pid) {
	//close(data_c_fd); // Will be closed in end of the outer loop
	close(forward_c_fd);
	break;
	} else {
	close(data_socket);
	close(forward_socket);
	exit(forward(data_c_fd, forward_c_fd) < 0 ? 1 : 0);
	//_exit(0);
	}
	}
	if(FD_ISSET(data_c_fd, &rfdset)) {
	char magic[sizeof MAGIC - 1];
	int s;
	do {
	s = read(data_c_fd, magic, sizeof magic);
	} while(s < 0 && errno == EINTR);
	if(s < sizeof magic) {
	if(s) fprintf(stderr, "%s: XXX closing connection due to incomplete packet (received %d byte(s))\n", argv[0], s);
	break;
	}
	if(memcmp(magic, MAGIC, sizeof magic)) {
	fprintf(stderr, "%s: Protocol mismatch\n", argv[0]);
	break;
	}
	uint16_t packet_type;
	do {
	s = read(data_c_fd, &packet_type, sizeof packet_type);
	} while(s < 0 && errno == EINTR);
	if(s < sizeof packet_type) {
	if(s) fprintf(stderr, "%s: XXX closing connection due to incomplete packet (received %d byte)\n", argv[0], s);
	break;
	}
	packet_type = ntohs(packet_type);
	if(packet_type != KEEP_ALIVE) {
	fprintf(stderr, "%s: Unknown packet type %hu received from client\n", argv[0], packet_type);
	break;
	}
	fprintf(stderr, "%s: keep alive from client\n", argv[0]);
	}
	} else {
	uint16_t packet_type = htons(KEEP_ALIVE);
	//uint16_t packet_type = KEEP_ALIVE;
	if(sync_write(data_c_fd, MAGIC, 4) < 0 \|\| sync_write(data_c_fd, &packet_type, sizeof packet_type) < 0) {
	perror("write");
	break;
	}
	}
	}
	close(data_c_fd);
	}
	}