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authorRick Jones <rick.jones2@hp.com>2014-11-06 10:37:54 -0800
committerDavid S. Miller <davem@davemloft.net>2014-11-07 15:45:50 -0500
commit36cbb2452cbafca64dcdd3578047433787900cf0 (patch)
tree3e50381574c3850fc2a6c76a14777daa821f85a0 /net/ipv6/udp.c
parentf46ad73ac6965f71d1a2ba217c4eb5b644e62949 (diff)
downloadlinux-36cbb2452cbafca64dcdd3578047433787900cf0.tar.gz
udp: Increment UDP_MIB_IGNOREDMULTI for arriving unmatched multicasts
As NIC multicast filtering isn't perfect, and some platforms are
quite content to spew broadcasts, we should not trigger an event
for skb:kfree_skb when we do not have a match for such an incoming
datagram.  We do though want to avoid sweeping the matter under the
rug entirely, so increment a suitable statistic.

This incorporates feedback from David L. Stevens, Karl Neiss and Eric
Dumazet.

V3 - use bool per David Miller

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/udp.c')
-rw-r--r--net/ipv6/udp.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9b6809232b17..b756355e9739 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -771,7 +771,7 @@ static void udp6_csum_zero_error(struct sk_buff *skb)
  */
 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
-		struct udp_table *udptable)
+		struct udp_table *udptable, int proto)
 {
 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
 	const struct udphdr *uh = udp_hdr(skb);
@@ -781,6 +781,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 	int dif = inet6_iif(skb);
 	unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node);
 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
+	bool inner_flushed = false;
 
 	if (use_hash2) {
 		hash2_any = udp6_portaddr_hash(net, &in6addr_any, hnum) &
@@ -803,6 +804,7 @@ start_lookup:
 		    (uh->check || udp_sk(sk)->no_check6_rx)) {
 			if (unlikely(count == ARRAY_SIZE(stack))) {
 				flush_stack(stack, count, skb, ~0);
+				inner_flushed = true;
 				count = 0;
 			}
 			stack[count++] = sk;
@@ -821,7 +823,10 @@ start_lookup:
 	if (count) {
 		flush_stack(stack, count, skb, count - 1);
 	} else {
-		kfree_skb(skb);
+		if (!inner_flushed)
+			UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI,
+					 proto == IPPROTO_UDPLITE);
+		consume_skb(skb);
 	}
 	return 0;
 }
@@ -873,7 +878,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	 */
 	if (ipv6_addr_is_multicast(daddr))
 		return __udp6_lib_mcast_deliver(net, skb,
-				saddr, daddr, udptable);
+				saddr, daddr, udptable, proto);
 
 	/* Unicast */