ipfwd.c

/**
 *	ratched - TLS connection router that performs a man-in-the-middle attack
 *	Copyright (C) 2017-2017 Johannes Bauer
 *
 *	This file is part of ratched.
 *
 *	ratched 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; this program is ONLY licensed under
 *	version 3 of the License, later versions are explicitly excluded.
 *
 *	ratched 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 ratched; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *	Johannes Bauer <JohannesBauer@gmx.de>
**/

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "logging.h"
#include "ipfwd.h"

int tcp_accept(uint16_t port_nbo) {
	int sd = socket(AF_INET, SOCK_STREAM, 0);
	if (sd == -1) {
		return -1;
	}

	{
		int enable = 1;
		if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable)) < 0) {
		    logmsg(LLVL_ERROR, "setsockopt(SO_REUSEADDR) failed: %s", strerror(errno));
			close(sd);
			return -1;
		}
	}

	struct sockaddr_in serv_addr;
	memset(&serv_addr, 0, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	serv_addr.sin_port = port_nbo;

	if (bind(sd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1) {
		logmsg(LLVL_ERROR, "Binding socket on " PRI_IPv4_PORT " failed: %s", FMT_IPv4_PORT(serv_addr), strerror(errno));
		close(sd);
		return -1;
	}

    if (listen(sd, 1) == -1) {
		logmsg(LLVL_ERROR, "Listening on bound socket failed: %s", strerror(errno));
		close(sd);
		return -1;
	}

	int peer_sd = accept(sd, NULL, NULL);
	if (peer_sd == -1) {
		logmsg(LLVL_ERROR, "Accepting on bound socket failed: %s", strerror(errno));
		close(sd);
		return -1;
	}

	close(sd);
	return peer_sd;
}

int tcp_connect(uint32_t ip_nbo, uint16_t port_nbo) {
	int sd = socket(AF_INET, SOCK_STREAM, 0);
	if (sd == -1) {
		return -1;
	}

	struct sockaddr_in peer;
	memset(&peer, 0, sizeof(peer));
	peer.sin_family = AF_INET;
	peer.sin_addr.s_addr = ip_nbo;
	peer.sin_port = port_nbo;

	logmsg(LLVL_DEBUG, "Connecting to " PRI_IPv4 ":%d for SD %d", FMT_IPv4(ip_nbo), ntohs(port_nbo), sd);
	if (connect(sd, (struct sockaddr*)&peer, sizeof(peer)) == -1) {
		int saved_errno = errno;
		close(sd);
		errno = saved_errno;
		return -1;
	}

	return sd;
}