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>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9b68092..b756355 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -771,7 +771,7 @@
*/
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 @@
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 @@
(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 @@
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 @@
*/
if (ipv6_addr_is_multicast(daddr))
return __udp6_lib_mcast_deliver(net, skb,
- saddr, daddr, udptable);
+ saddr, daddr, udptable, proto);
/* Unicast */