/*********************************************************************
*
* ARP Module for Microchip TCP/IP Stack
*
*********************************************************************
* FileName: ARP.c
* Dependencies: string.h
* stacktsk.h
* helpers.h
* arp.h
* mac.h
* Processor: PIC18, PIC24F, PIC24H, dsPIC30F, dsPIC33F
* Complier: Microchip C18 v3.02 or higher
* Microchip C30 v2.01 or higher
* Company: Microchip Technology, Inc.
*
* Software License Agreement
*
* This software is owned by Microchip Technology Inc. ("Microchip")
* and is supplied to you for use exclusively as described in the
* associated software agreement. This software is protected by
* software and other intellectual property laws. Any use in
* violation of the software license may subject the user to criminal
* sanctions as well as civil liability. Copyright 2006 Microchip
* Technology Inc. All rights reserved.
*
* This software is provided "AS IS." MICROCHIP DISCLAIMS ALL
* WARRANTIES, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, NOT LIMITED
* TO MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
* INFRINGEMENT. Microchip shall in no event be liable for special,
* incidental, or consequential damages.
*
*
* Author Date Comment
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Nilesh Rajbharti 5/1/01 Original (Rev 1.0)
* Nilesh Rajbharti 2/9/02 Cleanup
* Nilesh Rajbharti 5/22/02 Rev 2.0 (See version.log for detail)
********************************************************************/
#include <string.h>
#include "..\Include\StackTsk.h"
#include "..\Include\Helpers.h"
#include "..\Include\ARP.h"
#include "..\Include\MAC.h"
// ARP Operation codes.
#define ARP_OPERATION_REQ 0x01u
#define ARP_OPERATION_RESP 0x02u
// ETHERNET packet type as defined by IEEE 802.3
#define HW_ETHERNET (0x0001u)
#define ARP_IP (0x0800u)
// ARP packet
typedef struct _ARP_PACKET
{
WORD HardwareType;
WORD Protocol;
BYTE MACAddrLen;
BYTE ProtocolLen;
WORD Operation;
MAC_ADDR SenderMACAddr;
IP_ADDR SenderIPAddr;
MAC_ADDR TargetMACAddr;
IP_ADDR TargetIPAddr;
} ARP_PACKET;
// Helper function
static void SwapARPPacket(ARP_PACKET *p);
/*********************************************************************
* Function: BOOL ARPGet(NODE_INFO* remote, BYTE* opCode)
*
* PreCondition: ARP packet is ready in MAC buffer.
*
* Input: remote - Remote node info
* opCode - Buffer to hold ARP op code.
*
* Output: TRUE if a valid ARP packet was received.
* FALSE otherwise.
*
* Side Effects: None
*
* Overview: None
*
* Note: None
********************************************************************/
BOOL ARPGet(NODE_INFO *remote, BYTE *opCode)
{
ARP_PACKET packet;
MACGetArray((BYTE*)&packet, sizeof(packet));
MACDiscardRx();
SwapARPPacket(&packet);
if ( packet.HardwareType != HW_ETHERNET ||
packet.MACAddrLen != sizeof(MAC_ADDR) ||
packet.ProtocolLen != sizeof(IP_ADDR) )
{
return FALSE;
}
if ( packet.Operation == ARP_OPERATION_RESP )
{
*opCode = ARP_REPLY;
}
else if ( packet.Operation == ARP_OPERATION_REQ )
*opCode = ARP_REQUEST;
else
{
*opCode = ARP_UNKNOWN;
return FALSE;
}
if(packet.TargetIPAddr.Val == AppConfig.MyIPAddr.Val)
{
remote->MACAddr = packet.SenderMACAddr;
remote->IPAddr = packet.SenderIPAddr;
return TRUE;
}
else
return FALSE;
}
/*********************************************************************
* Function: BOOL ARPPut(NODE_INFO* more, BYTE opCode)
*
* PreCondition: None
*
* Input: remote - Remote node info
* opCode - ARP op code to send
*
* Output: TRUE - The ARP packet was generated properly
* FALSE - Unable to allocate a TX buffer
*
* Side Effects: None
*
* Overview: None
*
* Note: None
********************************************************************/
BOOL ARPPut(NODE_INFO *remote, BYTE opCode)
{
ARP_PACKET packet;
BUFFER MyTxBuffer = MACGetTxBuffer(TRUE);
// Do not respond if there is no room to generate the ARP reply
if(MyTxBuffer == INVALID_BUFFER)
return FALSE;
MACSetTxBuffer(MyTxBuffer, 0);
packet.HardwareType = HW_ETHERNET;
packet.Protocol = ARP_IP;
packet.MACAddrLen = sizeof(MAC_ADDR);
packet.ProtocolLen = sizeof(IP_ADDR);
if ( opCode == ARP_REQUEST )
{
packet.Operation = ARP_OPERATION_REQ;
packet.TargetMACAddr.v[0] = 0xff;
packet.TargetMACAddr.v[1] = 0xff;
packet.TargetMACAddr.v[2] = 0xff;
packet.TargetMACAddr.v[3] = 0xff;
packet.TargetMACAddr.v[4] = 0xff;
packet.TargetMACAddr.v[5] = 0xff;
}
else
{
packet.Operation = ARP_OPERATION_RESP;
packet.TargetMACAddr = remote->MACAddr;
}
packet.SenderMACAddr = AppConfig.MyMACAddr;
packet.SenderIPAddr = AppConfig.MyIPAddr;
// Check to see if target is on same subnet, if not, find Gateway MAC.
// Once we get Gateway MAC, all access to remote host will go through Gateway.
if((packet.SenderIPAddr.Val ^ remote->IPAddr.Val) & AppConfig.MyMask.Val)
{
packet.TargetIPAddr = AppConfig.MyGateway;
}
else
packet.TargetIPAddr = remote->IPAddr;
SwapARPPacket(&packet);
MACPutHeader(&packet.TargetMACAddr, MAC_ARP, sizeof(packet));
MACPutArray((BYTE*)&packet, sizeof(packet));
MACFlush();
return TRUE;
}
/*********************************************************************
* Function: static void SwapARPPacket(ARP_PACKET* p)
*
* PreCondition: None
*
* Input: p - ARP packet to be swapped.
*
* Output: None
*
* Side Effects: None
*
* Overview: None
*
* Note: None
********************************************************************/
static void SwapARPPacket(ARP_PACKET *p)
{
p->HardwareType = swaps(p->HardwareType);
p->Protocol = swaps(p->Protocol);
p->Operation = swaps(p->Operation);
}