From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: ARP table question Date: Wed, 12 Nov 2008 14:10:26 -0800 Message-ID: <491B5452.6020709@candelatech.com> References: <491B1600.4080505@candelatech.com> <491B1841.9050404@candelatech.com> <491B31EB.4050304@candelatech.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------070103070709000309040004" Cc: Patrick McHardy To: NetDev Return-path: Received: from mail.candelatech.com ([208.74.158.172]:46761 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755151AbYKLWKb (ORCPT ); Wed, 12 Nov 2008 17:10:31 -0500 In-Reply-To: <491B31EB.4050304@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------070103070709000309040004 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Ben Greear wrote: > I have 500 mac-vlans on a system talking to 500 other > mac-vlans. My problem is that the arp-table gets extremely > huge because every time an arp-request comes in on all mac-vlans, > a stale arp entry is added for each mac-vlan. I have filtering > turned on, but that doesn't help because the neigh_event_ns call > below will cause a stale neighbor entry to be created regardless > of whether a replay will be sent or not. > > Maybe the neigh_event code should be below the checks for dont_send, > and only create check neigh_event_ns if we are !dont_send? The attached patch makes it work much better for me. The patch will cause the code to NOT create a stale neighbor entry if we are not going to respond to the ARP request. The old code *would* create a stale entry even if we are not going to respond. This is against 2.6.25.15. Signed-off-by: Ben Greear Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com --------------070103070709000309040004 Content-Type: text/x-patch; name="patch0.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="patch0.patch" diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 8c16b42..dd454b7 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -872,18 +872,18 @@ static int arp_process(struct sk_buff *skb) addr_type = rt->rt_type; if (addr_type == RTN_LOCAL) { - n = neigh_event_ns(&arp_tbl, sha, &sip, dev); - if (n) { - int dont_send = 0; - - if (!dont_send) - dont_send |= arp_ignore(in_dev,sip,tip); - if (!dont_send && IN_DEV_ARPFILTER(in_dev)) - dont_send |= arp_filter(sip,tip,dev); - if (!dont_send) - arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); + int dont_send = 0; - neigh_release(n); + if (!dont_send) + dont_send |= arp_ignore(in_dev,sip,tip); + if (!dont_send && IN_DEV_ARPFILTER(in_dev)) + dont_send |= arp_filter(sip,tip,dev); + if (!dont_send) { + n = neigh_event_ns(&arp_tbl, sha, &sip, dev); + if (n) { + arp_send(ARPOP_REPLY,ETH_P_ARP,sip,dev,tip,sha,dev->dev_addr,sha); + neigh_release(n); + } } goto out; } else if (IN_DEV_FORWARD(in_dev)) { --------------070103070709000309040004--