diff --git a/include/net.h b/include/net.h
index eeea466..fd19c42 100644
--- a/include/net.h
+++ b/include/net.h
@@ -298,7 +298,7 @@ struct arp_hdr {
 /* Codes for NOT_REACH */
 #define ICMP_NOT_REACH_PORT	3	/* Port unreachable		*/
 
-typedef struct icmphdr {
+struct icmp_hdr {
 	uchar		type;
 	uchar		code;
 	ushort		checksum;
@@ -314,8 +314,10 @@ typedef struct icmphdr {
 		} frag;
 		uchar data[0];
 	} un;
-} ICMP_t;
+};
 
+#define ICMP_HDR_SIZE		(sizeof(struct icmp_hdr))
+#define IP_ICMP_HDR_SIZE	(IP_HDR_SIZE + ICMP_HDR_SIZE)
 
 /*
  * Maximum packet size; used to allocate packet storage.
diff --git a/net/net.c b/net/net.c
index 6d34254..4cdd9cd 100644
--- a/net/net.c
+++ b/net/net.c
@@ -825,7 +825,7 @@ static inline struct ip_udp_hdr *NetDefragment(struct ip_udp_hdr *ip, int *lenp)
 static void receive_icmp(struct ip_udp_hdr *ip, int len,
 			IPaddr_t src_ip, struct ethernet_hdr *et)
 {
-	ICMP_t *icmph = (ICMP_t *)&ip->udp_src;
+	struct icmp_hdr *icmph = (struct icmp_hdr *)&ip->udp_src;
 
 	switch (icmph->type) {
 	case ICMP_REDIRECT:
diff --git a/net/ping.c b/net/ping.c
index 04a594c..3102521 100644
--- a/net/ping.c
+++ b/net/ping.c
@@ -100,7 +100,7 @@ void ping_start(void)
 
 void ping_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
 {
-	ICMP_t *icmph = (ICMP_t *)&(ip->udp_src);
+	struct icmp_hdr *icmph = (struct icmp_hdr *)&ip->udp_src;
 	IPaddr_t src_ip;
 
 	switch (icmph->type) {