From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-da0-f43.google.com (mail-da0-f43.google.com [209.85.210.43]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id D6E7221F17D; Tue, 11 Dec 2012 08:59:58 -0800 (PST) Received: by mail-da0-f43.google.com with SMTP id u36so1968401dak.16 for ; Tue, 11 Dec 2012 08:59:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; bh=3xqGGkvT2K1nejTxJbv32r1L565kt/ZAuiF5QMMA+gU=; b=rORwy73Go+bixqIfTng/20G/KH55G3Ouh97vqwF9R9B1Fyd+VLrSVvp970f4MZOqpJ KC1MRWmj6xpFiil2jzKesN3YEWHtLcH+G2q0wqZdziWJQZo1zhenZGYlrIMP3NnnouHi JP87kSXIY3XmadvXavwOisi3Fe9Q5Bq6pS/p5ipomjIzaJ1KBtbQ8bCBadYwymOC9RD/ NdEdjX28i7Vh3iHDskC8b9BbDawVcjmn23uSQHpdAGkiKVj+MDCZ4vbMajuEFTFyh2gh qaTNBtefM4PchN9CLH3nS2/XqXgcSOHZxMWoC4liCemjDy/qbWUxVVmVEwavtb8inxJo rZlQ== Received: by 10.66.85.74 with SMTP id f10mr46595182paz.38.1355245198308; Tue, 11 Dec 2012 08:59:58 -0800 (PST) Received: from [172.19.242.31] ([172.19.242.31]) by mx.google.com with ESMTPS id hs2sm14037286pbc.22.2012.12.11.08.59.56 (version=SSLv3 cipher=OTHER); Tue, 11 Dec 2012 08:59:57 -0800 (PST) From: Eric Dumazet To: Ketan Kulkarni In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Tue, 11 Dec 2012 08:59:55 -0800 Message-ID: <1355245195.27891.108.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Cc: cerowrt-devel@lists.bufferbloat.net, bloat Subject: Re: [Cerowrt-devel] [Bloat] TCP TFO client behaviour X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Dec 2012 16:59:59 -0000 On Tue, 2012-12-11 at 22:18 +0530, Ketan Kulkarni wrote: > Hi, > I am testing tcp tfo behavior with httping client and polipo server. > > One observation from my TFO testing -If for a connection server sends > a cookie to client, client always does TFO for subsequent connections. > This is ok. > > If for some reason, server stops supporting TFO (either because server > got restarted without TFO support (in my case) or because path changed > and the nw node is dropping packet with unknown syn option or > stripping the option), client does not clear up its cookie cache. It > always sends data in syn and server never acks the syn-data and client > retransmits. > > As per kernel code -if syn-data is not acked it is retransmitted > immediately - with the assumption first syn was dropped (but the > assumption server stopped supporting TFO might not have been > considered) > > My opinion is to flush the cookie for this server and re-attempt the > cookie "negotiation" on subsequent connection. > > Your thoughts? I really wonder why this is sent to these lists instead of netdev ?