From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: ARP table question Date: Wed, 12 Nov 2008 11:43:39 -0800 Message-ID: <491B31EB.4050304@candelatech.com> References: <491B1600.4080505@candelatech.com> <491B1841.9050404@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: NetDev To: Patrick McHardy Return-path: Received: from mail.candelatech.com ([208.74.158.172]:38401 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751879AbYKLTno (ORCPT ); Wed, 12 Nov 2008 14:43:44 -0500 In-Reply-To: <491B1841.9050404@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: 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? This is the code I'm talking about, in arp.c (in kernel 2.6.25.15) if (arp->ar_op == htons(ARPOP_REQUEST) && ip_route_input(skb, tip, sip, 0, dev) == 0) { rt = (struct rtable*)skb->dst; addr_type = rt->rt_type; if (addr_type == RTN_LOCAL) { n = neigh_event_ns(&arp_tbl, sha, &sip, dev); 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); Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com