udp6: add missing rehash callback to udplite

After commit 23b0269e58 ("net: udp6: prefer listeners bound to an
address"), UDP-Lite only works when specifying a local address for
the sockets.

This is related to the problem addressed in the commit 719f835853
("udp: add rehash on connect()"). Moreover, __udp6_lib_lookup() now
looks for a socket immediately in the secondary hash table.

And this issue was found with LTP/network tests as well.

Fixes: 23b0269e58 ("net: udp6: prefer listeners bound to an address")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/udp.c

@@ -102,7 +102,7 @@ int udp_v6_get_port(struct sock *sk, unsigned short snum)
 	return udp_lib_get_port(sk, snum, hash2_nulladdr);
 }
 
-static void udp_v6_rehash(struct sock *sk)
+void udp_v6_rehash(struct sock *sk)
 {
 	u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
 					  &sk->sk_v6_rcv_saddr,

net/ipv6/udp_impl.h

@@ -13,6 +13,7 @@ int __udp6_lib_err(struct sk_buff *, struct inet6_skb_parm *, u8, u8, int,
 		   __be32, struct udp_table *);
 
 int udp_v6_get_port(struct sock *sk, unsigned short snum);
+void udp_v6_rehash(struct sock *sk);
 
 int udpv6_getsockopt(struct sock *sk, int level, int optname,
 		     char __user *optval, int __user *optlen);

net/ipv6/udplite.c

@@ -49,6 +49,7 @@ struct proto udplitev6_prot = {
 	.recvmsg	   = udpv6_recvmsg,
 	.hash		   = udp_lib_hash,
 	.unhash		   = udp_lib_unhash,
+	.rehash		   = udp_v6_rehash,
 	.get_port	   = udp_v6_get_port,
 	.memory_allocated  = &udp_memory_allocated,
 	.sysctl_mem	   = sysctl_udp_mem,