icmp.c

此文档为采用FPGA实现的以太网MAC层

#include "ip.h"
#include "mac.h"
#include "serial.h"
#include "icmp.h"
#include "mac_low.h"

ICMPHEADER icmp_header;


extern Uint16 data_buffer[100];
extern PACKET_STRUCT txpacket;

void icmp_process(ICMPHEADER *packet,Uint16 data_len, Uint16 src_ip_h, Uint16 src_ip_l)
{
    Uint16 len;

    //Test if PING
    if (packet->type == ICMP_PING)
    {
       len = data_len - ICMP_SIZE/2;        //Len now holds payload length in words

       //read back len*2 bytes
       //mac_read(len,(Uint16 *) data_buffer);

       icmp_handler(packet,data_len,src_ip_h,src_ip_l);
    }

}

void icmp_handler(ICMPHEADER *packet,Uint16 data_len, Uint16 src_ip_h, Uint16 src_ip_l)
{
    Uint16 len,*buf,x,*buf2;
    Uint8 *tmpptr;
    Uint32 word;

    //Test if PING
    if (packet->type == ICMP_PING)
    {


       //Modify packet and send out
       packet->type = ICMP_ECHO;
       packet->checksum = 0x0000;

       len = data_len - ICMP_SIZE/2;        //Len now holds payload length in words

       //Set buffer to point afer packet
       //buf = (Uint16 *) (EMAC_RX_PTR + ETH_SIZE + IP_SIZE + ICMP_SIZE);
       word = (Uint32) packet;
       word += (ICMP_SIZE);
       //dbg_string((Uint16 *) &word,2);
       buf = (Uint16 *) (word);

       //Fill in checksum
       packet->checksum = ip_chksum2((Uint16 *) packet,ICMP_SIZE/2,buf,len);


       //fill out data portion
       //packet_reset();
       //packet_add(data_buffer, len);
       //packet_add((Uint16 *) packet,ICMP_SIZE/2);

       //Copy data buffer to tx buffer
       buf2 = (Uint16 *) (EMAC_TX_PTR+ICMP_DATA_OFFSET);
       for (x=0;x<len;x++)
       {
          buf2[x]=buf[x];
       }

       //Copy header into Tx Buffer
       buf2 = (Uint16 *) (EMAC_TX_PTR+ICMP_OFFSET);
       buf = (Uint16 *) packet;

       for (x=0;x<(ICMP_SIZE/2);x++)
       {
          buf2[x]=buf[x];
       }


       //Send back to IP layer
       ip_send(src_ip_h,src_ip_l,data_len,PROTOCOL_ICMP);

    }


}