From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH net-next] udp: increment UDP_NO_PORTS when dropping unmatched multicasts Date: Wed, 01 Oct 2014 21:14:31 +0400 Message-ID: <542C3677.5020505@cogentembedded.com> References: <20141001151921.7131E29003A2@tardy> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net To: Rick Jones , netdev@vger.kernel.org Return-path: Received: from mail-la0-f42.google.com ([209.85.215.42]:63152 "EHLO mail-la0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752976AbaJAROg (ORCPT ); Wed, 1 Oct 2014 13:14:36 -0400 Received: by mail-la0-f42.google.com with SMTP id mk6so814751lab.15 for ; Wed, 01 Oct 2014 10:14:34 -0700 (PDT) In-Reply-To: <20141001151921.7131E29003A2@tardy> Sender: netdev-owner@vger.kernel.org List-ID: Hello. On 10/01/2014 07:19 PM, Rick Jones wrote: > 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) { I don't see where this new variable is changed. It's always 0 here. > + 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; > } WBR, Sergei