icmp.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"


/*
 * ICMP packet definition
 */
typedef struct _ICMP_PACKET
{
    BYTE    Type;
    BYTE    Code;
    WORD    Checksum;
    WORD    Identifier;
    WORD    SequenceNumber;
    BYTE    Data[MAX_ICMP_DATA];
} ICMP_PACKET;
#define ICMP_HEADER_SIZE    (sizeof(ICMP_PACKET) - MAX_ICMP_DATA)


 void SwapICMPPacket(ICMP_PACKET* p);


/*********************************************************************
 * Function:        BOOL ICMPGet(ICMP_CODE *code,
 *                              BYTE *data,
 *                              BYTE *len,
 *                              WORD *id,
 *                              WORD *seq)
 *
 * PreCondition:    MAC buffer contains ICMP type packet.
 *
 * Input:           code    - Buffer to hold ICMP code value
 *                  data    - Buffer to hold ICMP data
 *                  len     - Buffer to hold ICMP data length
 *                  id      - Buffer to hold ICMP id
 *                  seq     - Buffer to hold ICMP seq
 *
 * Output:          TRUE if valid ICMP packet was received
 *                  FALSE otherwise.
 *
 * Side Effects:    None
 *
 * Overview:        None
 *
 * Note:            None
 ********************************************************************/
BOOL ICMPGet(ICMP_CODE *code,
             BYTE *data,
             BYTE *len,
             WORD *id,
             WORD *seq)
{
    ICMP_PACKET packet;
    WORD checksums[2];
    WORD CalcChecksum;
    WORD ReceivedChecksum;
    char        i,j;
    BYTE        *c;

    MACGetArray((BYTE*)&packet, ICMP_HEADER_SIZE);
    c=(BYTE*)&packet;
    for(i=0;i<8;i++)
     { 
        while(!TXSTAbits.TRMT);
        putcUSART(*(c++));
     }
    ReceivedChecksum = packet.Checksum;
    packet.Checksum = 0;

    checksums[0] = ~CalcIPChecksum((BYTE*)&packet, ICMP_HEADER_SIZE);

    *len -= ICMP_HEADER_SIZE;

    MACGetArray(data, *len);
    if((*len)>0)
     { c=data;
       j=*len;
       for(i=0;i<j;i++)
        { 
            while(!TXSTAbits.TRMT);
            putcUSART(*(c++));
        }
     }
    checksums[1] = ~CalcIPChecksum(data, *len);

    CalcChecksum = CalcIPChecksum((BYTE*)checksums, 2 * sizeof(WORD));

    SwapICMPPacket(&packet);

    *code = packet.Type;
    *id = packet.Identifier;
    *seq = packet.SequenceNumber;

    return ( CalcChecksum == ReceivedChecksum );
}

/*********************************************************************
 * Function:        void ICMPPut(NODE_INFO *remote,
 *                               ICMP_CODE code,
 *                               BYTE *data,
 *                               BYTE len,
 *                               WORD id,
 *                               WORD seq)
 *
 * PreCondition:    ICMPIsTxReady() == TRUE
 *
 * Input:           remote      - Remote node info
 *                  code        - ICMP_ECHO_REPLY or ICMP_ECHO_REQUEST
 *                  data        - Data bytes
 *                  len         - Number of bytes to send
 *                  id          - ICMP identifier
 *                  seq         - ICMP sequence number
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Note:            A ICMP packet is created and put on MAC.
 *
 ********************************************************************/
void ICMPPut(NODE_INFO *remote,
             ICMP_CODE code,
             BYTE *data,
             BYTE len,
             WORD id,
             WORD seq)
{
    ICMP_PACKET packet;

    packet.Code             = 0;
    packet.Type             = code;
    packet.Checksum         = 0;
    packet.Identifier       = id;
    packet.SequenceNumber   = seq;

    memcpy((void*)packet.Data, (void*)data, len);

    SwapICMPPacket(&packet);

    packet.Checksum         = CalcIPChecksum((BYTE*)&packet,
                                    (WORD)(ICMP_HEADER_SIZE + len));

    IPPutHeader(remote,
                IP_PROT_ICMP,
                (WORD)(ICMP_HEADER_SIZE + len));

    IPPutArray((BYTE*)&packet, (WORD)(ICMP_HEADER_SIZE + len));

    MACFlush();
}

/*********************************************************************
 * Function:        void SwapICMPPacket(ICMP_PACKET* p)
 *
 * PreCondition:    None
 *
 * Input:           p - ICMP packet header
 *
 * Output:          ICMP packet is swapped
 *
 * Side Effects:    None
 *
 * Overview:        None
 *
 * Note:            None
 ********************************************************************/
void SwapICMPPacket(ICMP_PACKET* p)
{
    p->Identifier           = swaps(p->Identifier);
    p->SequenceNumber       = swaps(p->SequenceNumber);
    p->Checksum             = swaps(p->Checksum);
}