/*
 * tcp.c
 *
 *  Created on: 29.09.2011
 *      Author: Oliver
 */

#include <stdio.h>
#include <thread.h>
#include <string.h>

#include "tcp.h"
#include "in.h"
#include "socket.h"
#include "sys/net/net_help/net_help.h"


void printArrayRange_tcp(uint8_t *udp_header, uint16_t len)
	{
	int i = 0;
	printf("-------------MEMORY-------------\n");
	for (i = 0; i < len; i++)
		{
		printf("%#x ", *(udp_header+i));
		}
	printf("-------------MEMORY-------------\n");
	}

uint16_t tcp_csum(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header){
    uint16_t sum;
    uint16_t len = ipv6_header->length;

	sum = len + IPPROTO_TCP;
	sum = csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
	sum = csum(sum, (uint8_t*)tcp_header, len);
    return (sum == 0) ? 0xffff : HTONS(sum);
}

void tcp_packet_handler (void)
	{
	msg_t m_recv_ip, m_send_ip, m_recv_tcp, m_send_tcp;
	struct ipv6_hdr_t *ipv6_header;
	struct tcp_hdr_t *tcp_header;
	uint8_t *payload;
	socket_internal_t *tcp_socket = NULL;
	uint16_t chksum;

	while (1)
		{
		msg_receive(&m_recv_ip);
		ipv6_header = ((struct ipv6_hdr_t*)&buffer);
		tcp_header = ((struct tcp_hdr_t*)(&buffer[IPV6_HDR_LEN]));
		payload = &buffer[IPV6_HDR_LEN+TCP_HDR_LEN];

		chksum = tcp_csum(ipv6_header, tcp_header);
		printf("Checksum is %x!\n", chksum);

		tcp_socket = get_tcp_socket(tcp_header->dst_port);

		if ((chksum != 0xffff) && (tcp_socket != NULL))
			{
			uint8_t tcp_flags = tcp_header->reserved_flags;
			//TODO: URG Flag and PSH flag are currently being ignored

			if (IS_TCP_ACK(tcp_flags))
				{
				// only ACK Bit set
				}
			else if (IS_TCP_RST(tcp_flags))
				{
				// only RST Bit set
				}
			else if (IS_TCP_SYN(tcp_flags))
				{
				// only SYN Bit set, request new queued socket

				socket_t *new_socket = new_tcp_queued_socket(ipv6_header, tcp_header, tcp_socket);
				if (new_socket != NULL)
					{
					// notify socket function accept(..) that a new connection request has arrived
					m_send_tcp.content.ptr = (char*)buffer;
					m_send_tcp.content.value = IPV6_HDR_LEN + ipv6_header->length;
					msg_send(&m_send_tcp, tcp_socket->pid, 0);
					}
				else
					{
					printf("Dropped TCP Message because an error occured while requesting a new queued socket!\n");
					}
				}
			else if (IS_TCP_SYN_ACK(tcp_flags))
				{
				// only SYN and ACK Bit set
				}
			else if (IS_TCP_FIN(tcp_flags))
				{
				// only FIN Bit set
				}
			else if (IS_TCP_FIN_ACK(tcp_flags))
				{
				// only FIN and ACK Bit set
				}
			else
				{
				// TODO: any other case
				}
			}
		else
			{
			printf("Wrong checksum (%x) or no corresponding socket found!\n", chksum);
			}

		tcp_socket = NULL;
		msg_reply(&m_recv_ip, &m_send_ip);
		}
	}