From mboxrd@z Thu Jan 1 00:00:00 1970 From: raj@tardy.usa.hp.com (Rick Jones) Subject: [PATCH net-next] udp: increment UDP_NO_PORTS when dropping unmatched multicasts Date: Wed, 1 Oct 2014 08:19:21 -0700 (PDT) Message-ID: <20141001151921.7131E29003A2@tardy> Cc: To: Return-path: Received: from g2t1383g.austin.hp.com ([15.217.136.92]:31998 "EHLO g2t1383g.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479AbaJAPTZ (ORCPT ); Wed, 1 Oct 2014 11:19:25 -0400 Received: from g5t1625.atlanta.hp.com (g5t1625.atlanta.hp.com [15.192.137.8]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by g2t1383g.austin.hp.com (Postfix) with ESMTPS id E0FAD3030 for ; Wed, 1 Oct 2014 15:19:24 +0000 (UTC) Sender: netdev-owner@vger.kernel.org List-ID: From: Rick Jones When there is absolutely no match for an incoming UDP multicast we should increment a suitable UDP statistic in addition to the kfree_skb(). When there were some matches, we should not and simply call consume_skb(). Signed-off-by: Rick Jones --- Noticed __udp4_lib_mcast_deliver showing-up in a perf dropped packet profile on a system sitting on a network with a bunch of Windows boxes sending what they are fond of sending. Verified that UDP_MIB_NOPORTS increments when it was not before and hit the system with a bit of netperf multicast UDP_RR but that is the extent of the testing performed. diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index cd0db54..376e3d3 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1656,6 +1656,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, int dif = skb->dev->ifindex; unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node); unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10); + unsigned int inner_flushed = 0; if (use_hash2) { hash2_any = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum) & @@ -1694,8 +1695,12 @@ start_lookup: */ if (count) { flush_stack(stack, count, skb, count - 1); - } else { + } else if (!inner_flushed) { + UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, 0); kfree_skb(skb); + } else { + /* there were matches flushed in the for_each */ + consume_skb(skb); } return 0; }