icmp.c

CP2201和51单片机实现ARP ICMP IP UDP协议

/*==============================================*/
//	ICMP协议程序
//	FOR AVR DEV 1.0
/*==============================================*/

#include  "ne2000.h"
#include "ip.h"
#include "netcomm.h"
//extern union NetNode xdata myNode;
//extern unsigned int chksum(unsigned char xdata *check,unsigned int size);
/*==============================================*/
//	函数名称:	PING应答
/*==============================================*/
void ping_answer(INT8U xdata *inbuf,union ip_address_type ip_addr, INT16U len)
{
	unsigned int 	i;
	unsigned char  xdata *icmp_outbuf;
	icmp_head xdata * icmp_in,*icmp_out;
	icmp_in=(icmp_head xdata * )(inbuf+34);
	icmp_out=(icmp_head xdata * )(icmp_outbuf+34);
	if(icmp_in->type == 0x08)
	{		
	    	for (i = 42; i < len+42; i++)	
	 	    icmp_outbuf[i] = inbuf[i];
	        icmp_out->type = 0x00;	
	        icmp_out->id=icmp_in->id;
	        icmp_out->seq=icmp_in->seq;
			icmp_out->option=icmp_in->option;
		    icmp_out->crc = 0;
	    	icmp_out->crc =~chksum(icmp_outbuf+34,len); 
            ip_send(icmp_outbuf,ip_addr, 0x01, len );		
	}  
}