diff --git a/include/net/tcp.h b/include/net/tcp.h
index 06a3023080c0..39e47c4e4f19 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -493,10 +493,11 @@ static inline u32 tcp_cookie_time(void)
 
 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
 			      u16 *mssp);
-__u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mss);
+__u32 cookie_v4_init_sequence(struct sock *sk, const struct sk_buff *skb,
+			      __u16 *mss);
 #else
 static inline __u32 cookie_v4_init_sequence(struct sock *sk,
-					    struct sk_buff *skb,
+					    const struct sk_buff *skb,
 					    __u16 *mss)
 {
 	return 0;
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index c86624b36a62..c0c75688896e 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -170,7 +170,8 @@ u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
 }
 EXPORT_SYMBOL_GPL(__cookie_v4_init_sequence);
 
-__u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp)
+__u32 cookie_v4_init_sequence(struct sock *sk, const struct sk_buff *skb,
+			      __u16 *mssp)
 {
 	const struct iphdr *iph = ip_hdr(skb);
 	const struct tcphdr *th = tcp_hdr(skb);