tcp: tcp_md5_hash_skb_data() frag_list handling

tcp_md5_hash_skb_data() should handle skb->frag_list, and eventually
recurse.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -2999,6 +2999,7 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
 	const unsigned head_data_len = skb_headlen(skb) > header_len ?
 				       skb_headlen(skb) - header_len : 0;
 	const struct skb_shared_info *shi = skb_shinfo(skb);
+	struct sk_buff *frag_iter;
 
 	sg_init_table(&sg, 1);
 
@@ -3013,6 +3014,10 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
 			return 1;
 	}
 
+	skb_walk_frags(skb, frag_iter)
+		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
+			return 1;
+
 	return 0;
 }