#include"basetype.h"
#include"common.h"

#include "packet_lib.h"

/*
description: 这个函数用于编码ARP报文。
input:
	pucSrcMac: 发送者MAC地址，指向一个长度为6的无符号8位整数数组。
	pucDstMac: 接收者MAC地址，指向一个长度为6的无符号8位整数数组。
	uiSrcIPv4Addr: 发送者IPv4地址，一个32位无符号整数。
	uiDstIPv4Addr: 接收者IPv4地址，一个32位无符号整数。
	ucOpCode: 操作类型，一个无符号8位整数。
	pucBuffer: 指向用于存储编码后ARP报文的无符号8位整数数组。
output:
	返回编码后ARP报文的长度，一个无符号16位整数。
return:
	返回编码后ARP报文的长度，一个无符号16位整数。
tip：无
*/
UINT16 ArpLib_EncodeArp(UINT8* pucSrcMac, UINT8* pucDstMac,
	UINT32 uiSrcIPv4Addr, UINT32 uiDstIPv4Addr, UINT8 ucOpCode,
	UINT8* pucBuffer)

{
	UINT8* pucPointer = pucBuffer;
	pucPointer = pucPointer + ETHERHEAD_OFFSET_LENGTH;

	UINT16 Hardware_Type = 0x0001;//以太硬件类型
	*pucPointer = (Hardware_Type & 0xFF00) >> 8;
	pucPointer++;
	*pucPointer = (Hardware_Type & 0x00FF);
	pucPointer++;
	//memcpy(pucPointer, &Hardware_Type, Hardware_Type_LEN);
	//pucPointer += Hardware_Type_LEN;

	*pucPointer = (ETHERNET_PROTOCOL_IPV4 & 0xFF00) >> 8;//上层协议类型
	pucPointer++;
	*pucPointer = (ETHERNET_PROTOCOL_IPV4 & 0x00FF);
	pucPointer++;
	*pucPointer = MAC_BYTE;//MAC地址长度 6
	pucPointer++;
	*pucPointer = IPV4_BYTE;//IP地址长度 4
	pucPointer++;

	*pucPointer = (ucOpCode & 0xFF00) >> 8;
	pucPointer++;
	*pucPointer = (ucOpCode & 0x00FF);
	pucPointer++;
	//memcpy(pucPointer, &ucOpCode, 2); //操作类型
	//pucPointer += 2;

	memcpy(pucPointer, pucSrcMac, MAC_BYTE);
	pucPointer += MAC_BYTE;

	memcpy(pucPointer, PacketLib_Displacement(uiSrcIPv4Addr), IPV4_BYTE);
	pucPointer += IPV4_BYTE;

	memcpy(pucPointer, pucDstMac, MAC_BYTE);
	pucPointer += MAC_BYTE;

	memcpy(pucPointer, PacketLib_Displacement(uiDstIPv4Addr), IPV4_BYTE);
	pucPointer += IPV4_BYTE;

	return 28;
}

/*
description: 这个函数用于解码ARP报文。
input:
	pstArpHeader: 指向ARP头部结构体的指针。
	pucBuffer: 指向需要解码的ARP报文的无符号8位整数数组。
	usPacketLen: ARP报文的长度，一个无符号32位整数。
output: 无
return: 无
tip：无
*/
VOID ArpLib_DecodeArp(ARPHEAD_S* pstArpHeader, UINT8* pucBuffer, UINT32 usPacketLen)
{
	UINT8* pucPointer = pucBuffer;

	//  参数 报文长度 usPacketLen
	if (usPacketLen < 42)
	{
		printf("Arp header message length error\n");
		exit(-1);
	}
	if (42 == usPacketLen)
	{
		pucPointer = pucPointer + ETHERHEAD_OFFSET_LENGTH;
	}
	else
	{
		pucPointer = pucPointer + ETHERHEAD_OFFSET_LENGTH + 4;//加上vlan的4字节
	}
	//硬件类型
	pstArpHeader->Hardware_Type_LEN = ((UINT16)(*pucPointer) << 8);
	pucPointer++;
	pstArpHeader->Hardware_Type_LEN += (UINT16)(*pucPointer);
	pucPointer++;

	//协议类型
	pstArpHeader->Treaty_Type_LEN = ((UINT16)(*pucPointer) << 8);
	pucPointer++;
	pstArpHeader->Treaty_Type_LEN += (UINT16)(*pucPointer);
	pucPointer++;

	//硬件地址长度
	pstArpHeader->MAC_LEN = (*pucPointer);
	pucPointer++;
	//协议地址长度
	pstArpHeader->IP_LEN = (*pucPointer);
	pucPointer++;

	//操作类型
	pstArpHeader->ucOpCode = (UINT16)(*pucPointer << 8);
	pucPointer++;
	pstArpHeader->ucOpCode += (UINT16)(*pucPointer);
	pucPointer++;

	//源MAC地址
	memcpy(pstArpHeader->pucSrcMac, pucPointer, MAC_BYTE);
	pucPointer += MAC_BYTE;

	//源IP地址
	pstArpHeader->uiSrcIPv4Addr = PacketLib_Undisplacement(pucPointer);
	pucPointer += IPV4_BYTE;

	//目的MAC地址
	memcpy(pstArpHeader->pucDstMac, pucPointer, MAC_BYTE);
	pucPointer += MAC_BYTE;

	//目的IP地址
	pstArpHeader->uiDstIPv4Addr = PacketLib_Undisplacement(pucPointer);
	pucPointer += IPV4_BYTE;
}