/*
 * DhcpProbe.h
 *
 *  Created on: 2014. 8. 17.
 *      Author: sound79@gmail.com
 */
#ifndef DHCPPROBE_H_
#define DHCPPROBE_H_

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <linux/if_ether.h>
#include <string>

#define MAX_DHCP_CHADDR_LEN		16
#define MAX_DHCP_SNAME_LEN		64
#define MAX_DHCP_FILE_LEN		128
#define MAX_DHCP_OPTIONS_LEN	312

#define SERVER_DHCP_PORT		67
#define CLIENT_DHCP_PORT		68

#define CHECK_WAITTING_DHCP_OFFER_TIME		2

typedef struct DHCPPacket_t
{
	unsigned char  op;
	unsigned char  htype;
	unsigned char  hlen;
	unsigned char  hops;
#if 0
	unsigned long xid;
	unsigned short secs;
	unsigned short flags;
#else
	u_int32_t xid;
	u_int16_t secs;
	u_int16_t flags;
#endif
	struct in_addr ciaddr;
	struct in_addr yiaddr;
	struct in_addr siaddr;
	struct in_addr giaddr;
	unsigned char chaddr [MAX_DHCP_CHADDR_LEN];
	char sname [MAX_DHCP_SNAME_LEN];
	char file [MAX_DHCP_FILE_LEN];
	char options[MAX_DHCP_OPTIONS_LEN];

	void clear()
	{
		op = 0, htype = 0, hlen = 0 , hops = 0;
		xid = 0, secs = 0, flags = 0;
		memset(&ciaddr, 0, sizeof(ciaddr));
		memset(&yiaddr, 0, sizeof(ciaddr));
		memset(&siaddr, 0, sizeof(ciaddr));
		memset(&giaddr, 0, sizeof(ciaddr));
		memset(chaddr, 0, MAX_DHCP_CHADDR_LEN);
		memset(sname, 0, MAX_DHCP_SNAME_LEN);
		memset(file, 0, MAX_DHCP_FILE_LEN);
		memset(options, 0, MAX_DHCP_OPTIONS_LEN);
	}
}DHCPPacket;

using namespace std;

class DHCPProbe
{
private:
	DHCPPacket mDHCPPacket;
	string mEthName;
	string mEthMacAddress;
	int	mDHCPSocket;
	unsigned long mPacketXID;

private:
	bool makeDHCPSocket();
	void closeDHCPSocket();
	bool getMacAddress();
	bool makeDHCPDiscoveryPacket();
	bool sendDHCPDiscovery();
	int recvDHCPOffer(char *buffer, int buffer_size, struct sockaddr_in *sourceAddress);
	int waitDHCPOfferPacket();

public:
	DHCPProbe(string ethName = "eth0");
	virtual ~DHCPProbe();
	int CheckDHCPServerExist();
};

#endif /* DHCPPROBE_H_ */