tinc/src/protocol_misc.c

/*
    protocol_misc.c -- handle the meta-protocol, miscellaneous functions
    Copyright (C) 1999-2005 Ivo Timmermans,
                  2000-2012 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 "system.h"

#include "conf.h"
#include "connection.h"
#include "logger.h"
#include "meta.h"
#include "net.h"
#include "netutl.h"
#include "protocol.h"
#include "utils.h"

int maxoutbufsize = 0;

bool send_ping(connection_t *c) {
	c->status.pinged = true;
	c->last_ping_time = now;

	return send_request(c, "%d", PING);
}

bool ping_h(connection_t *c) {
	return send_pong(c);
}

bool send_pong(connection_t *c) {
	return send_request(c, "%d", PONG);
}

bool pong_h(connection_t *c) {
	c->status.pinged = false;

	/* Successful connection, reset timeout if this is an outgoing connection. */

	if(c->outgoing) {
		c->outgoing->timeout = 0;
		c->outgoing->cfg = NULL;

		if(c->outgoing->ai) {
			freeaddrinfo(c->outgoing->ai);
		}

		c->outgoing->ai = NULL;
		c->outgoing->aip = NULL;
	}

	return true;
}

/* Sending and receiving packets via TCP */

bool send_tcppacket(connection_t *c, const vpn_packet_t *packet) {
	/* If there already is a lot of data in the outbuf buffer, discard this packet.
	   We use a very simple Random Early Drop algorithm. */

	if(2.0 * c->outbuflen / (float)maxoutbufsize - 1 > (float)rand() / (float)RAND_MAX) {
		return true;
	}

	if(!send_request(c, "%d %hd", PACKET, packet->len)) {
		return false;
	}

	return send_meta(c, (char *)packet->data, packet->len) && flush_meta(c);
}

bool tcppacket_h(connection_t *c) {
	length_t len;

	if(sscanf(c->buffer, "%*d %hu", &len) != 1) {
		logger(LOG_ERR, "Got bad %s from %s (%s)", "PACKET", c->name,
		       c->hostname);
		return false;
	}

	/* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */

	c->tcplen = len;

	return true;
}