From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next v2 0/5] Make tcp-metrics source-address aware Date: Fri, 10 Jan 2014 17:38:57 -0500 (EST) Message-ID: <20140110.173857.1280113609417951585.davem@davemloft.net> References: <1389193559-16756-1-git-send-email-christoph.paasch@uclouvain.be> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, ycheng@google.com, ja@ssi.bg To: christoph.paasch@uclouvain.be Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:43311 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751234AbaAJWi6 (ORCPT ); Fri, 10 Jan 2014 17:38:58 -0500 In-Reply-To: <1389193559-16756-1-git-send-email-christoph.paasch@uclouvain.be> Sender: netdev-owner@vger.kernel.org List-ID: From: Christoph Paasch Date: Wed, 8 Jan 2014 16:05:54 +0100 > Currently tcp-metrics only stores per-destination addresses. This brings > problems, when a host has multiple interfaces (e.g., a smartphone having > WiFi/3G): > > For example, a host contacting a server over WiFi will store the tcp-metrics > per destination IP. If then the host contacts the same server over 3G, the > same tcp-metrics will be used, although the path-characteristics are completly > different (e.g., the ssthresh is probably not the same). > > In case of TFO this is not a problem, as the server will provide us a new cookie > once he saw our SYN+DATA with an incorrect cookie. > It may be (in case of carrier-grade NAT), that we keep the same public IP but > have a different private IP. Thus, we better reuse the old cookie even if our > source-IP has changed. However, this scenario is probably very uncommon, as > carriers try to provide the same src-IP to the clients behind their CGN. > > Patches 1 + 2 add the source-IP to the tcp metrics. > > Patches 3 to 5 modify the netlink-api to support the source-IP. From now on, > when using the command "ip tcp_metrics delete address ADDRESS" all entries > which match this destination IP will be deleted. > > Today's iproute2 will complain when doing "ip tcp_metrics flush PREFIX" if > several entries are present for the same destination-IP but with different > source-IPs: > > root@client:~/test# ip tcp_metrics > 10.2.1.2 age 3.640sec rtt 16250us rttvar 15000us cwnd 10 > 10.2.1.2 age 4.030sec rtt 18750us rttvar 15000us cwnd 10 > root@client:~/test# ip tcp_metrics flush 10.2.1.2/16 > Failed to send flush request > : No such process > > > Follow-up patches will modify iproute2 to handle this correctly and allow > specifying the source-IP in the get/del commands. > > > v2: Added the patch that allows to selectively get/del of tcp-metrics based > on src-IP and moved the patch that adds the new netlink attribute before > the other patches. Looks good, series applied, thanks Christoph.