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=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3EB2FC433E2 for ; Wed, 2 Sep 2020 00:42:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AEF2206F0 for ; Wed, 2 Sep 2020 00:42:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="I19hRBxp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726946AbgIBAmP (ORCPT ); Tue, 1 Sep 2020 20:42:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726064AbgIBAmN (ORCPT ); Tue, 1 Sep 2020 20:42:13 -0400 Received: from mail-io1-xd44.google.com (mail-io1-xd44.google.com [IPv6:2607:f8b0:4864:20::d44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9019AC061244 for ; Tue, 1 Sep 2020 17:42:12 -0700 (PDT) Received: by mail-io1-xd44.google.com with SMTP id d190so4012340iof.3 for ; Tue, 01 Sep 2020 17:42:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=VKHLvH1J2VJaorrEDWRQw/ehzOWUl6yg1KAg6n1TROo=; b=I19hRBxpEcAkNRm32DFSRNfrJpGFUftTrMJGlcgwQedtviTgFN40wxw1AJ9sCAZ2aE cjWx4iXTs7I8QcazQlFJAVxLDH3tmDtLvqgC9liJfuS/t+WkAyGllaIG7xtqNPJJ3Q7a U8LIih1zwlmvslboF0eBhmJuyGdSzCM0DoFNX1EstvlFkgT2S8A2gtlf1Q1yQMUDs46j 9TO8CveRJbFGQwQv5it49m00c3InA1rhP7pKzZ83XHE9KxvWOXR18l3Dk/y62Tizu5j5 eOhzS6w2h6sNnho+12zWgWq8jvJmYjp4RtTcBIzBh4JzvPMw4537DXR13bN4F/MWFrRY UTcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=VKHLvH1J2VJaorrEDWRQw/ehzOWUl6yg1KAg6n1TROo=; b=aJfS0kw8KknHnkMXsyb9IgkJcEx/f1ZNmd37d5iK5G6HTsu2tSzNPq68OL8EO6+jQo 8UpM12KCAyk5XMR/RKeRKxgtZ3FM65HkJkyTzd4iBOG7pE0HIDTPZYuSLNcZtxysQnzv HZm5m79V4QsE8yMN5cigroyuNJKdjrsy44523pNwYyVmEvdIIRX4HW3YcJXCFxq+WiFe +20fqR4bkZFtTSlSgTSkqCcb2boHk7UFU4lB8AlRzIhv8hKizb/M8TVAZKj3YHxzFkju wFHt7oOnyp/dk4zvGeI2Yx80DC0RmJRKoj7UtZ5TaWDLRVMkqt1Mclx104LASl9R0cHy D7+w== X-Gm-Message-State: AOAM531WY+T2F7d3niZqFx6zvPIpnEjkQkEro3z4wycYYxdorPq1qg8b FQwEqTEidHevCeocUrK2ySeqla5oBCxPiA== X-Google-Smtp-Source: ABdhPJwkkSYMfRRK3ctK0iam8JjLv3Q5ok+h/i1y5ZpmtqAeTl5uda/iwOnrOzSFwRyWfmrE75Kyfg== X-Received: by 2002:a6b:6e0b:: with SMTP id d11mr1443011ioh.155.1599007331818; Tue, 01 Sep 2020 17:42:11 -0700 (PDT) Received: from Davids-MacBook-Pro.local ([2601:282:803:7700:883e:eb9e:60a1:7cfb]) by smtp.googlemail.com with ESMTPSA id d19sm1292141iod.38.2020.09.01.17.42.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 01 Sep 2020 17:42:10 -0700 (PDT) Subject: Re: PMTUD broken inside network namespace with multipath routing To: mastertheknife Cc: netdev@vger.kernel.org References: <1b4ebdb3-8840-810a-0d5e-74e2cf7693bf@gmail.com> <962617e5-9dec-6715-d550-4cf3ee414cf6@gmail.com> From: David Ahern Message-ID: <2f0e9d12-1780-cd1f-891d-940274f9105d@gmail.com> Date: Tue, 1 Sep 2020 18:42:10 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9/1/20 4:40 AM, mastertheknife wrote: > > P.S: while reading the relevant code in the kernel, i think i spotted > some mistake in net/ipv4/route.c, in function "update_or_create_fnhe". > It looks like it loops over all the exceptions for the nexthop entry, > but always overwriting the first (and only) entry, so effectively only > 1 exception can exist per nexthop entry. > Line 678: > "if (fnhe) {" > Should probably be: > "if (fnhe && fnhe->fnhe_daddr == daddr) {" > Right above that line is: for (fnhe = rcu_dereference(hash->chain); fnhe; fnhe = rcu_dereference(fnhe->fnhe_next)) { if (fnhe->fnhe_daddr == daddr) break; depth++; } so fnhe is set based on daddr match.