#include "basetype.h"
#include "common.h"
#include "ethernet_lib.h"
#include "packet_lib.h"

/*
 * description:  封装报文的IP头部分(固定的20字节)
 *
 * input:
 *	ucTTL					ttl
 *	ucProtocol				ucProtocol
 *	uiSrcIPv4Addr			源ip地址
 *uiDstIPv4Addr				目的ip地址
 *
 * output：
 *	pucBuffer				报文
 * return：					固定的20字节ipv4头
 * tip：						IN是空宏，表示改参数是输入
 */
UINT32 Ipv4Lib_EncodeIPv4Header(UINT8 ucTTL, UINT8 ucProtocol, 
	UINT32 uiSrcIPv4Addr, UINT32 uiDstIPv4Addr, UINT8* pucBuffer) // , UINT16 TotalLength
{ 
	// UINT16 Head_check,自己算
	UINT8 *pucPointer = pucBuffer;
	pucPointer += MAC_BYTE + MAC_BYTE + 2;

	*pucPointer = (UINT8)((4 & 0x0F) << 4);		   // 4位的版本号
	*pucPointer = *pucPointer + (UINT8)(5 & 0x0F); // 4位的首部长度
	pucPointer++;

	*pucPointer = 0X00; // 服务类型
	pucPointer++;

	// 总长度，封装的时候不知道	，需要调用PacketLib_UpdateTollength设置
	pucPointer += 2;

	// 标识
	UINT16 id = 0X0000;
	*pucPointer = (UINT8)((id & 0xFF00) >> 8);
	pucPointer++;
	*pucPointer = (UINT8)(id & 0x00FF);
	pucPointer++;

	// 标志和片位移
	UINT16 flag_offset = 0X0000;
	*pucPointer = (UINT8)((flag_offset & 0xFF00) >> 8);
	pucPointer++;
	*pucPointer = (UINT8)(flag_offset & 0x00FF);
	pucPointer++;

	// TTL
	*pucPointer = ucTTL;
	pucPointer++;
	// 协议
	*pucPointer = ucProtocol;
	pucPointer++;

	// 计算校验和
	UINT16 Head_check = PacketLib_CRCCheak(pucBuffer, 5 * 4);
	*pucPointer = (Head_check & 0XFF00) >> 8;
	pucPointer++;
	*pucPointer = (Head_check & 0X00FF);
	pucPointer++;

	// IPV4地址
	memcpy(pucPointer, PacketLib_Displacement(uiSrcIPv4Addr), 4);
	pucPointer += 4;

	// IPV4地址
	memcpy(pucPointer, PacketLib_Displacement(uiDstIPv4Addr), 4);
	pucPointer += 4;

	// todo:

	return 20; // 固定部分
}

/*
 * description:  解封装报文的ipv4部分
 *
 * input:
 *	pucBuffer				报文
 *	usPacketLen				报文长度
 *
 * output：
 *	pstIpv4Header			报文的Ipv4部分
 * return：					icmp部分长度
 * tip：						IN是空宏，表示改参数是输入
 */

VOID Ipv4Lib_DecodeIPv4Header(UINT8 *pucBuffer, UINT16 usPacketLen, 
	IPV4HEAD_S *pstIpv4Header)
{
	if (usPacketLen < 34)
	{
		printf("Ip header message length error\n");
		exit(-1);
	}
	UINT8* pucPointer = pucBuffer;
	ETHERNET_VLAN_S ustEthernetVlanHeader;
	UINT16 usVlanFlag;
	usVlanFlag = 0x8100;
	pucPointer = pucBuffer;
	// 得到以太头中是否有vlan
	EthernetLib_DecodeEthernetVlanHeader(pucBuffer, usPacketLen, &ustEthernetVlanHeader);
	if (usVlanFlag == ustEthernetVlanHeader.usEtype)
	{
		// 偏移18字节以太头
		pucPointer += ETHERHEAD_OFFSET_LENGTH + VLAN_ETYPE + VLAN_ID;
	}
	else
	{
		// 偏移14字节以太头
		pucPointer += ETHERHEAD_OFFSET_LENGTH;
	}

	// 版本
	pstIpv4Header->ucVersion = ((*pucPointer) & 0xF0);
	// 首部长度
	pstIpv4Header->ucHeadlen = ((*pucPointer) & 0x0F);
	pucPointer++;

	pstIpv4Header->ucTos = *pucPointer;
	pucPointer++;

	pstIpv4Header->usTotal_len = ((UINT16)(*pucPointer) << 8);
	pucPointer++;
	pstIpv4Header->usTotal_len += (UINT16)(*pucPointer);
	pucPointer++;

	pstIpv4Header->usId = ((UINT16)(*pucPointer) << 8);
	pucPointer++;
	pstIpv4Header->usId += (UINT16)(*pucPointer);
	pucPointer++;

	UINT16 flag_offset = 0;
	flag_offset = ((UINT16)(*pucPointer) << 8);
	pucPointer++;
	flag_offset += (UINT16)(*pucPointer);
	pucPointer++;

	pstIpv4Header->usFlag = (flag_offset & 0b1110000000000000) >> 13;
	pstIpv4Header->usOffset = (flag_offset & 0b0001111111111111);

	pstIpv4Header->ucTTL = *pucPointer;
	pucPointer++;

	pstIpv4Header->ucProtocol = *pucPointer;
	pucPointer++;

	UINT16 Head_check = PacketLib_CRCCheak(pucBuffer, 5 * 4);
	pstIpv4Header->usHead_check = Head_check;
	pucPointer += 2;

	pstIpv4Header->uiSrcIPv4Addr = PacketLib_Undisplacement(pucPointer);

	pucPointer += IPV4_BYTE;
	pstIpv4Header->uiDstIPv4Addr = PacketLib_Undisplacement(pucPointer);
	pucPointer += IPV4_BYTE;
}