From patchwork Thu Dec 30 03:28:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: CGEL X-Patchwork-Id: 12701219 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDDE5C433FE for ; Thu, 30 Dec 2021 03:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235305AbhL3D3G (ORCPT ); Wed, 29 Dec 2021 22:29:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231751AbhL3D3F (ORCPT ); Wed, 29 Dec 2021 22:29:05 -0500 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DBC2C061574; Wed, 29 Dec 2021 19:29:05 -0800 (PST) Received: by mail-qt1-x831.google.com with SMTP id m18so20185435qtk.3; Wed, 29 Dec 2021 19:29:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=m9cYq+sFAaUH0aCXhcS4yUtbxJNyxo3lAJslQcNG+d8=; b=a/P8PPXfgXvPR8+Y2sL0hiZl5RbK0O0SnXFh1NPCxDtuhlWO6n9k8IRkccpjxl+dJc kH8Xr3+cg15aNYxISEMldGXd9sb3MgSr2UXRR2BRWmAPAmkRY3DUu76Xxbg8vYjTNXPJ tjvusHtLdby/MKzBd/J+IM/am6DMrmgnAqFoCZGkcI9cjOVSx1zjqJ2mLs1DBUQpbRgj 3oCHoTc5TULx2zvA3wFjZeVv4t3U8PE7BNXm8NbB/9n2TbU7jzYO7NGQ1oZOqqFI1FTy 4BRYfpIPUf/xNWWaZF1B+6hDUCHfEPTHEir2hGNmW6zinhJbrDui/xvIZwz9Xjxn5NCu 2ZrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=m9cYq+sFAaUH0aCXhcS4yUtbxJNyxo3lAJslQcNG+d8=; b=VnqHjc/QvoK2ZhUroo3JhHFCXC77geYGXqSJfixUEReaqp5GaVL61mg1HzDOK0pZgj A9AFPZIqhRHvV9yeKUdqGEw6NqI6ISdxI3LOuXbtAji6uhBgPcwV9pQkxAMhHsyQ62GM /locqvUhf+6Nc1+biuqZLyDppAUTJlioy4eUi0da5sEf9WI2ZUw+X+dpZFm802UQ1Z4E ljo3c+iXFLNYTWc62+NkkCUu/UXjobBhlBsZHtoNCxDzXt2SW+mu+yAHyyIn6ipnVrID /78ZqPW/6058QtMPGJC5kPsSxZmESKYs5PK5FobtjIWMqOM0hVnRsZgh8eElox+Jiba9 a8MA== X-Gm-Message-State: AOAM531VgizIq8SZfqAndfFpJ+BT3AbuZUOPPPSP43RBt3g9q66UYKFv gvR8bVbXSb+PP0pfldAxTfo= X-Google-Smtp-Source: ABdhPJy4uMnPTS1hDfGdbbNYjNwKiGuSs+n0MPUuobef2snDX4UwkmWyP/Bpn7HsKQgLirfoSwlu/w== X-Received: by 2002:a05:622a:186:: with SMTP id s6mr25260160qtw.477.1640834944544; Wed, 29 Dec 2021 19:29:04 -0800 (PST) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id u10sm20027416qtx.3.2021.12.29.19.29.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Dec 2021 19:29:03 -0800 (PST) From: cgel.zte@gmail.com X-Google-Original-From: xu.xin16@zte.com.cn To: kuba@kernel.org, davem@davemloft.net, corbet@lwn.net Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, xu xin , Zeal Robot Subject: [PATCH v2] Documentation: fix outdated interpretation of ip_no_pmtu_disc Date: Thu, 30 Dec 2021 03:28:56 +0000 Message-Id: <20211230032856.584972-1-xu.xin16@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211229121536.06d270e5@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> References: <20211229121536.06d270e5@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: xu xin The updating way of pmtu has changed, but documentation is still in the old way. So this patch updates the interpretation of ip_no_pmtu_disc and min_pmtu. See commit 28d35bcdd3925 ("net: ipv4: don't let PMTU updates increase route MTU") Reported-by: Zeal Robot Signed-off-by: xu xin --- Documentation/networking/ip-sysctl.rst | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index c04431144f7a..2572eecc3e86 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -25,7 +25,8 @@ ip_default_ttl - INTEGER ip_no_pmtu_disc - INTEGER Disable Path MTU Discovery. If enabled in mode 1 and a fragmentation-required ICMP is received, the PMTU to this - destination will be set to min_pmtu (see below). You will need + destination will be set to the smallest of the old MTU to + this destination and min_pmtu (see below). You will need to raise min_pmtu to the smallest interface MTU on your system manually if you want to avoid locally generated fragments. @@ -49,7 +50,8 @@ ip_no_pmtu_disc - INTEGER Default: FALSE min_pmtu - INTEGER - default 552 - minimum discovered Path MTU + default 552 - minimum Path MTU. Unless this is changed mannually, + each cached pmtu will never be lower than this setting. ip_forward_use_pmtu - BOOLEAN By default we don't trust protocol path MTUs while forwarding