text: #ifndef ICMP_H
  #define ICMP_H
  
  #include "netdev.h"
  #include "ipv4.h"
  
  
  
  struct icmp {
  	unsigned char icmp_type;
  	unsigned char icmp_code;
  	unsigned short icmp_cksum;
  	union {
  		struct {
  			unsigned short id;	/* identifier */
  			unsigned short seq;	/* sequence number */
  		} echo;
  		unsigned int gw;		/* icmp redirect gateway */
  		unsigned int pad;
  	} icmp_un;
  	unsigned char icmp_data[];
  } __attribute__((packed));
      
  void icmp_incoming(struct netdev *netdev,struct eth_hdr *hdr );
  
  #endif
  