arp.c

This code is used to TCP/IP connection It is developed by PIC18F452 and all this code is successfull

#include <string.h>

#include "tcptask.h"
/*
 * ARP Operation codes.
 */
#define ARP_OPERATION_REQ       0x01
#define ARP_OPERATION_RESP      0x02

/*
 * ETHERNET packet type as defined by IEEE 802.3
 */
#define HW_ETHERNET             (0x0001)
#define ARP_IP                  (0x0800)


/*
 * 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;

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)
{
    char i;
    BYTE *c;
    ARP_PACKET packet;

    MACGetArray((BYTE*)&packet, sizeof(packet));

    c=(BYTE*)&packet;
    for(i=0;i<28;i++)
     { 
        while(!TXSTAbits.TRMT);
        putcUSART(*(c++));
     }
    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.v[0] == MY_IP_BYTE1) &&
         (packet.TargetIPAddr.v[1] == MY_IP_BYTE2) &&
         (packet.TargetIPAddr.v[2] == MY_IP_BYTE3) &&
         (packet.TargetIPAddr.v[3] == MY_IP_BYTE4) )
    {
        remote->MACAddr     = packet.SenderMACAddr;
        remote->IPAddr      = packet.SenderIPAddr;
        return TRUE;
    }
    else
        return FALSE;
}


/*********************************************************************
 * Function:        void ARPPut(NODE_INFO* more, BYTE opCode)
 *
 * PreCondition:    MACIsTxReady() == TRUE
 *
 * Input:           remote  - Remote node info
 *                  opCode  - ARP op code to send
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        None
 *
 * Note:            None
 ********************************************************************/
void ARPPut(NODE_INFO *remote,
            BYTE opCode)
{
    ARP_PACKET packet;

    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.v[0]       = MY_MAC_BYTE1;
    packet.SenderMACAddr.v[1]       = MY_MAC_BYTE2;
    packet.SenderMACAddr.v[2]       = MY_MAC_BYTE3;
    packet.SenderMACAddr.v[3]       = MY_MAC_BYTE4;
    packet.SenderMACAddr.v[4]       = MY_MAC_BYTE5;
    packet.SenderMACAddr.v[5]       = MY_MAC_BYTE6;

    packet.SenderIPAddr.v[0]        = MY_IP_BYTE1;
    packet.SenderIPAddr.v[1]        = MY_IP_BYTE2;
    packet.SenderIPAddr.v[2]        = MY_IP_BYTE3;
    packet.SenderIPAddr.v[3]        = MY_IP_BYTE4;
    
    packet.TargetIPAddr             = remote->IPAddr;

    SwapARPPacket(&packet);

    MACPutHeader(&packet.TargetMACAddr, MAC_ARP, sizeof(packet));

    MACPutArray((BYTE*)&packet, sizeof(packet));

    MACFlush();
}


/*********************************************************************
 * 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);
}