tcp-accept.c

/*
 * Dropbear SSH
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE. */

#include "includes.h"
#include "ssh.h"
#include "tcpfwd.h"
#include "dbutil.h"
#include "session.h"
#include "buffer.h"
#include "packet.h"
#include "listener.h"
#include "runopts.h"

#ifdef DROPBEAR_TCP_ACCEPT

static void cleanup_tcp(struct Listener *listener) {

	struct TCPListener *tcpinfo = (struct TCPListener*)(listener->typedata);

	m_free(tcpinfo->sendaddr);
	m_free(tcpinfo->listenaddr);
	m_free(tcpinfo);
}

static void tcp_acceptor(struct Listener *listener, int sock) {

	int fd;
	struct sockaddr_storage addr;
	socklen_t len;
	char ipstring[NI_MAXHOST], portstring[NI_MAXSERV];
	struct TCPListener *tcpinfo = (struct TCPListener*)(listener->typedata);

	len = sizeof(addr);

	fd = accept(sock, (struct sockaddr*)&addr, &len);
	if (fd < 0) {
		return;
	}

	if (getnameinfo((struct sockaddr*)&addr, len, ipstring, sizeof(ipstring),
				portstring, sizeof(portstring), 
				NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
		return;
	}

	if (send_msg_channel_open_init(fd, tcpinfo->chantype) == DROPBEAR_SUCCESS) {
		unsigned char* addr = NULL;
		unsigned int port = 0;

		if (tcpinfo->tcp_type == direct) {
			/* "direct-tcpip" */
			/* host to connect, port to connect */
			addr = tcpinfo->sendaddr;
			port = tcpinfo->sendport;
		} else {
			dropbear_assert(tcpinfo->tcp_type == forwarded);
			/* "forwarded-tcpip" */
			/* address that was connected, port that was connected */
			addr = tcpinfo->listenaddr;
			port = tcpinfo->listenport;
		}

		buf_putstring(ses.writepayload, addr, strlen(addr));
		buf_putint(ses.writepayload, port);

		/* originator ip */
		buf_putstring(ses.writepayload, ipstring, strlen(ipstring));
		/* originator port */
		buf_putint(ses.writepayload, atol(portstring));

		encrypt_packet();

	} else {
		/* XXX debug? */
		close(fd);
	}
}

int listen_tcpfwd(struct TCPListener* tcpinfo) {

	char portstring[NI_MAXSERV];
	int socks[DROPBEAR_MAX_SOCKS];
	struct Listener *listener = NULL;
	int nsocks;
	char* errstring = NULL;
	/* listen_spec = NULL indicates localhost */
	const char* listen_spec = NULL;

	TRACE(("enter listen_tcpfwd"))

	/* first we try to bind, so don't need to do so much cleanup on failure */
	snprintf(portstring, sizeof(portstring), "%d", tcpinfo->listenport);

	/* a listenaddr of "" will indicate all interfaces */
	if (opts.listen_fwd_all 
			&& (strcmp(tcpinfo->listenaddr, "localhost") != 0) ) {
		listen_spec = tcpinfo->listenaddr;
	}

	nsocks = dropbear_listen(listen_spec, portstring, socks, 
			DROPBEAR_MAX_SOCKS, &errstring, &ses.maxfd);
	if (nsocks < 0) {
		dropbear_log(LOG_INFO, "TCP forward failed: %s", errstring);
		m_free(errstring);
		TRACE(("leave listen_tcpfwd: dropbear_listen failed"))
		return DROPBEAR_FAILURE;
	}
	m_free(errstring);
	
	/* new_listener will close the socks if it fails */
	listener = new_listener(socks, nsocks, CHANNEL_ID_TCPFORWARDED, tcpinfo, 
			tcp_acceptor, cleanup_tcp);

	if (listener == NULL) {
		TRACE(("leave listen_tcpfwd: listener failed"))
		return DROPBEAR_FAILURE;
	}

	TRACE(("leave listen_tcpfwd: success"))
	return DROPBEAR_SUCCESS;
}

#endif /* DROPBEAR_TCP_ACCEPT */