1 files changed, 44 insertions, 0 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 32e0bef60d0a..fb23c2e63b52 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1260,6 +1260,49 @@ void udp_lib_unhash(struct sock *sk)
 }
 EXPORT_SYMBOL(udp_lib_unhash);
 
+/*
+ * inet_rcv_saddr was changed, we must rehash secondary hash
+ */
+void udp_lib_rehash(struct sock *sk, u16 newhash)
+{
+        if (sk_hashed(sk)) {
+                struct udp_table *udptable = sk->sk_prot->h.udp_table;
+                struct udp_hslot *hslot, *hslot2, *nhslot2;
+
+                hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
+                nhslot2 = udp_hashslot2(udptable, newhash);
+                udp_sk(sk)->udp_portaddr_hash = newhash;
+                if (hslot2 != nhslot2) {
+                        hslot = udp_hashslot(udptable, sock_net(sk),
+                                             udp_sk(sk)->udp_port_hash);
+                        /* we must lock primary chain too */
+                        spin_lock_bh(&hslot->lock);
+
+                        spin_lock(&hslot2->lock);
+                        hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
+                        hslot2->count--;
+                        spin_unlock(&hslot2->lock);
+
+                        spin_lock(&nhslot2->lock);
+                        hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+                                                 &nhslot2->head);
+                        nhslot2->count++;
+                        spin_unlock(&nhslot2->lock);
+
+                        spin_unlock_bh(&hslot->lock);
+                }
+        }
+}
+EXPORT_SYMBOL(udp_lib_rehash);
+
+static void udp_v4_rehash(struct sock *sk)
+{
+        u16 new_hash = udp4_portaddr_hash(sock_net(sk),
+                                          inet_sk(sk)->inet_rcv_saddr,
+                                          inet_sk(sk)->inet_num);
+        udp_lib_rehash(sk, new_hash);
+}
+
 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
         int rc;
@@ -1843,6 +1886,7 @@ struct proto udp_prot = {
         .backlog_rcv       = __udp_queue_rcv_skb,
         .hash              = udp_lib_hash,
         .unhash            = udp_lib_unhash,
+        .rehash            = udp_v4_rehash,
         .get_port          = udp_v4_get_port,
         .memory_allocated  = &udp_memory_allocated,
         .sysctl_mem        = sysctl_udp_mem,