/*
 *  Hans - IP over ICMP
 *  Copyright (C) 2009 Friedrich Schöller <friedrich.schoeller@gmail.com>
 *  
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 *  
 */

#ifndef ECHO_H
#define ECHO_H

#include <string>
#include <stdint.h>

class Echo
{
public:
	Echo(int maxPayloadSize);
	~Echo();

	int getFd() { return fd; }

	void send(int payloadLength, uint32_t realIp, bool reply, uint16_t id, uint16_t seq);
	int receive(uint32_t &realIp, bool &reply, uint16_t &id, uint16_t &seq);

	char *payloadBuffer() { return buffer + headerSize(); }

	static int headerSize();
protected:
	struct EchoHeader
	{
		uint8_t type;
		uint8_t code;
		uint16_t chksum;
		uint16_t id;
		uint16_t seq;
	}; // size = 8

	uint16_t icmpChecksum(const char *data, int length);

	int fd;
	int bufferSize;
	char *buffer;
};

#endif