From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B4D4C31E51 for ; Tue, 18 Jun 2019 11:40:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E456F2070B for ; Tue, 18 Jun 2019 11:40:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hp1/OTCP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729608AbfFRLkq (ORCPT ); Tue, 18 Jun 2019 07:40:46 -0400 Received: from mail-io1-f47.google.com ([209.85.166.47]:44737 "EHLO mail-io1-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729110AbfFRLkq (ORCPT ); Tue, 18 Jun 2019 07:40:46 -0400 Received: by mail-io1-f47.google.com with SMTP id s7so28878991iob.11; Tue, 18 Jun 2019 04:40:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jedWwHWh2EYefjIp3GoP3+SWfo9njQ+Y+pCfoemyVcc=; b=hp1/OTCPGu3jghRAd5Lz/F7MmLm8touJC8nLGPbmmBRTZUN5cb5ABAN3G510fwKi4Q c8Tg+286aH9wqzkA5MBt5ne9137D6k+u0pnJKk9QWSpNNEdjmxVdxL5a+HligF7jWXl6 rq3m9tvDN7ITtKiW2QesrebbXYEPqw5ryJLPmoMxf4fuIX3J2KkWzGv4MQUTb7xJH0XJ EEK2QSThTpY/GMOeWqYlxhVBaCOtnhqYpseyMzBTPQJeF9xzrKBLt2uGiHA7zvIa/3dJ 2/X6qKpLQYVojK6ktTqiag+cbzews6N45Ju8obCJjroLZeNAbJQ0Yy/9dVybqIxvg5Rx uNOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jedWwHWh2EYefjIp3GoP3+SWfo9njQ+Y+pCfoemyVcc=; b=L8gW2TiZveF7QL75W5Fz88ZXWB+qhZUQh3XfZtM/aIZFJVLAvXlphELm6aN/zLX3Ip oGz6yBP9XdjeUtljR0z8a0tmXIpF19fpW1AvKdq7djnw60n7GnjdGdVvATHM50kZwQHE WQ3KR73G48B+BjZ5JXX0Op5DxrnF5M5QfnTvQ3XkHo4/7qXmMTdYSH6nUdsc+wRy2vnb 4AKB1e3NQ/TGrfk9++HfUytCEwZ6YqBuTy8X5GDQuqu4H0o5s4D0HmHYPw/ODD+PkUNS EerkzsSp4V0LIOTTS5gZqQPtWB6iGDRsv2XKbYu318t2VjdYeVyhq84AY3gqF2z9gqy1 0vZQ== X-Gm-Message-State: APjAAAXiW62yW8ssn1d6p2in152RwGFl2pVQn1LT6mbzqg/R01eAvzQ/ mlHeL/khPjXUO2Kcvxe3es9zmxU2iU1zzP9gDTmQycEcwpeByA== X-Google-Smtp-Source: APXvYqyjuFBHVrtcRpdy05mpJo8XVNmpqsT30dMZqv9CEnKdOQPlahtuLMixdsLnf3wOKJil341hHPSpDney9b22gmM= X-Received: by 2002:a6b:9257:: with SMTP id u84mr3041645iod.278.1560858045113; Tue, 18 Jun 2019 04:40:45 -0700 (PDT) MIME-Version: 1.0 References: <20190618104041.unuonhmuvgnlty3l@breakpoint.cc> In-Reply-To: <20190618104041.unuonhmuvgnlty3l@breakpoint.cc> From: =?UTF-8?Q?=C4=B0brahim_Ercan?= Date: Tue, 18 Jun 2019 14:40:34 +0300 Message-ID: Subject: Re: Is this possible SYN Proxy bug? To: Florian Westphal Cc: netfilter@vger.kernel.org, netfilter-devel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Tue, Jun 18, 2019 at 1:40 PM Florian Westphal wrote: > > Problem is that we do not keep any state. Syncookes are restricted to 4 > mss value: > static __u16 const msstab[] = { > 536, > 1300, > 1440, /* 1440, 1452: PPPoE */ > 1460, > }; > > So, 1260 forces lowest value supported. > > The table was based off a research paper that had mss distribution > tables. Maybe more recent data is available and if things have changed > we could update the table accordingly. I am confused. So this statement from manual page is just a illusion? --mss maximum segment size Maximum segment size announced to clients. This must match the backend. I don't understand why these restriction exist. Why can't we set mss value same as what client send to us?