net/ipv6/udp: UDP encapsulation: move socket locking into udpv6_queue_rcv_skb()

In order to make sure that when the encap_rcv() hook is introduced it is
not called with the socket lock held, move socket locking from callers into
udpv6_queue_rcv_skb(), matching what happens in IPv4.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 6c0367f..bc533ea 100644 (file)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -558,14 +558,25 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
                        goto drop;
        }
 
+       if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
+               goto drop;
+
        skb_dst_drop(skb);
 
-       rc = __udpv6_queue_rcv_skb(sk, skb);
+       bh_lock_sock(sk);
+       rc = 0;
+       if (!sock_owned_by_user(sk))
+               rc = __udpv6_queue_rcv_skb(sk, skb);
+       else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
+               bh_unlock_sock(sk);
+               goto drop;
+       }
+       bh_unlock_sock(sk);
 
        return rc;
 drop:
-       atomic_inc(&sk->sk_drops);
        UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+       atomic_inc(&sk->sk_drops);
        kfree_skb(skb);
        return -1;
 }
@@ -614,37 +625,27 @@ static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
 static void flush_stack(struct sock **stack, unsigned int count,
                        struct sk_buff *skb, unsigned int final)
 {
-       unsigned int i;
+       struct sk_buff *skb1 = NULL;
        struct sock *sk;
-       struct sk_buff *skb1;
+       unsigned int i;
 
        for (i = 0; i < count; i++) {
-               skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
-
                sk = stack[i];
-               if (skb1) {
-                       if (sk_rcvqueues_full(sk, skb1, sk->sk_rcvbuf)) {
-                               kfree_skb(skb1);
-                               goto drop;
-                       }
-                       bh_lock_sock(sk);
-                       if (!sock_owned_by_user(sk))
-                               udpv6_queue_rcv_skb(sk, skb1);
-                       else if (sk_add_backlog(sk, skb1, sk->sk_rcvbuf)) {
-                               kfree_skb(skb1);
-                               bh_unlock_sock(sk);
-                               goto drop;
-                       }
-                       bh_unlock_sock(sk);
-                       continue;
+               if (likely(skb1 == NULL))
+                       skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
+               if (!skb1) {
+                       atomic_inc(&sk->sk_drops);
+                       UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
+                                         IS_UDPLITE(sk));
+                       UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
+                                         IS_UDPLITE(sk));
                }
-drop:
-               atomic_inc(&sk->sk_drops);
-               UDP6_INC_STATS_BH(sock_net(sk),
-                               UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
-               UDP6_INC_STATS_BH(sock_net(sk),
-                               UDP_MIB_INERRORS, IS_UDPLITE(sk));
+
+               if (skb1 && udpv6_queue_rcv_skb(sk, skb1) <= 0)
+                       skb1 = NULL;
        }
+       if (unlikely(skb1))
+               kfree_skb(skb1);
 }
 /*
  * Note: called only from the BH handler context,
@@ -784,39 +785,29 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
         * for sock caches... i'll skip this for now.
         */
        sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
+       if (sk != NULL) {
+               int ret = udpv6_queue_rcv_skb(sk, skb);
+               sock_put(sk);
 
-       if (sk == NULL) {
-               if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
-                       goto discard;
-
-               if (udp_lib_checksum_complete(skb))
-                       goto discard;
-               UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS,
-                               proto == IPPROTO_UDPLITE);
-
-               icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
+               /* a return value > 0 means to resubmit the input, but
+                * it wants the return to be -protocol, or 0
+                */
+               if (ret > 0)
+                       return -ret;
 
-               kfree_skb(skb);
                return 0;
        }
 
-       /* deliver */
-
-       if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf)) {
-               sock_put(sk);
+       if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
                goto discard;
-       }
-       bh_lock_sock(sk);
-       if (!sock_owned_by_user(sk))
-               udpv6_queue_rcv_skb(sk, skb);
-       else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
-               atomic_inc(&sk->sk_drops);
-               bh_unlock_sock(sk);
-               sock_put(sk);
+
+       if (udp_lib_checksum_complete(skb))
                goto discard;
-       }
-       bh_unlock_sock(sk);
-       sock_put(sk);
+
+       UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
+       icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
+
+       kfree_skb(skb);
        return 0;
 
 short_packet: