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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT 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 6DD14C43381 for ; Wed, 30 Dec 2020 08:49:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 32FB4223C8 for ; Wed, 30 Dec 2020 08:49:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726553AbgL3ItU (ORCPT ); Wed, 30 Dec 2020 03:49:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726161AbgL3ItU (ORCPT ); Wed, 30 Dec 2020 03:49:20 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AE70C061799; Wed, 30 Dec 2020 00:48:40 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id f9so9363723pfc.11; Wed, 30 Dec 2020 00:48:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id; bh=4hCJ1uMJpAFhFUoq0+DB5gxgdyiGzPgLXZHVoajEEEA=; b=jZ5uPlLqIv3Midv96JO3qpwpMYuUl5mEpPbhHrD1TG5aDs4y0i5BHq2aW2Gp4bawJj 0rSo5S7JVAJlTOtpXej+TeH7kgJq1ptxQ256UBgxQ2L5fdq59elydWcqeRAyIIYGP5Nw iJUlTpk7ybNzuzCX6f2KL389y8PhzG9+b0ldpWMq4OxpiAIAXpaRbD8GlfwP08wt1DsH 7GmWRAfEZL4BGjbToIvPoFdj07r4oM+pl0LypvD0+yroKig/VqFgP3lT/KglQ3WjjzyP z0bBJomrABKGhTqd9Qeeu734lXOrUrFpRXeKKZWZsRvVOsMFwPoJjta8moMMhc3wtbNn pHIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id; bh=4hCJ1uMJpAFhFUoq0+DB5gxgdyiGzPgLXZHVoajEEEA=; b=V/XBpRYvER74u4J0TipangLVGu5IaQnLAbyAxisxy1NG1vhGaG4K3+p7uBUrr0mip6 tZCIpNHOqgqBELWjQ6rnxnYekJd4SCl6X/0y+1R5A3pU/2sy4AkV0w4561USfsqg63Wn SEcFZFEhtXEJJXpbk2H8qKESCbA0GF9PFu0I37ss1iieTGJwnzvFFtsvrdhodZUQYc6T f03tAX40UDXyHA6CIeh5rmxCI/+6liUhpCVPeFr8g0O4MHua2NdmamtUUE8PWxOfjexG l5BfTJqcLFJbyLqpmxgQaX26CpVtdS7lRJZZWqyjoyOxk69Zp8O034DTo3JlxdzsAVe0 D4UA== X-Gm-Message-State: AOAM531KAGFaZQMY4VrNl7zzNtasG0rHIMOv3Pw6QOvD6nx+UsTqBbf3 OjUpuSeiBgKTZ+oWKdX1gg== X-Google-Smtp-Source: ABdhPJz3cKnMI1W2LJzGkOqSF/9K06oZXqmhH9iZ9eZ3hx06habQQOaW7fliF2+M4AyLu3TW3ChhFA== X-Received: by 2002:a65:6205:: with SMTP id d5mr51460297pgv.76.1609318119128; Wed, 30 Dec 2020 00:48:39 -0800 (PST) Received: from localhost.localdomain ([216.52.21.4]) by smtp.gmail.com with ESMTPSA id h1sm30907643pgj.59.2020.12.30.00.48.38 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 30 Dec 2020 00:48:38 -0800 (PST) From: Praveen Chaudhary X-Google-Original-From: Praveen Chaudhary To: davem@davemloft.net, kuba@kernel.org, corbet@lwn.net, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Allow user to set metric on default route learned via Router Advertisement. Date: Wed, 30 Dec 2020 00:48:32 -0800 Message-Id: <1609318113-12770-1-git-send-email-pchaudhary@linkedin.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow user to set metric on default route learned via Router Advertisement. Not: RFC 4191 does not say anything for metric for IPv6 default route. Fix: For IPv4, default route is learned via DHCPv4 and user is allowed to change metric using config etc/network/interfaces. But for IPv6, default route can be learned via RA, for which, currently a fixed metric value 1024 is used. Ideally, user should be able to configure metric on default route for IPv6 similar to IPv4. This fix adds sysctl for the same. Logs: ---------------------------------------------------------------- For IPv4: ---------------------------------------------------------------- Config in etc/network/interfaces ---------------------------------------------------------------- ``` auto eth0 iface eth0 inet dhcp metric 4261413864 ``` IPv4 Kernel Route Table: ---------------------------------------------------------------- ``` $ sudo route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.11.44.1 0.0.0.0 UG -33553432 0 0 eth0 ``` FRR Table, if default route is learned via routing protocol too. ---------------------------------------------------------------- ``` # show ip route Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP, T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > - selected route, * - FIB route S>* 0.0.0.0/0 [20/0] is directly connected, eth0, 00:00:03 K 0.0.0.0/0 [254/1000] via 172.21.47.1, eth0, 6d08h51m ``` ---------------------------------------------------------------- i.e. User can prefer Default Router learned via Routing Protocol, Similar behavior is not possible for IPv6, without this fix. ---------------------------------------------------------------- After fix [for IPv6]: ---------------------------------------------------------------- ``` sudo sysctl -w net.ipv6.conf.eth0.net.ipv6.conf.eth0.accept_ra_defrtr_metric=0x770003e9 ``` IP monitor: ---------------------------------------------------------------- ``` default via fe80::be16:65ff:feb3:ce8e dev eth0 proto ra metric 1996489705 pref high ``` Kernel IPv6 routing table ---------------------------------------------------------------- ``` Destination Next Hop Flag Met Ref Use If ::/0 fe80::be16:65ff:feb3:ce8e UGDAe 1996489705 0 0 eth0 ``` FRR Routing Table, if default route is learned via routing protocol. ---------------------------------------------------------------- # show ipv6 route Codes: K - kernel route, C - connected, S - static, R - RIPng, O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > - selected route, * - FIB route S>* ::/0 [20/0] is directly connected, eth0, 00:00:06 K ::/0 [119/1001] via fe80::be16:65ff:feb3:ce8e, eth0, 6d07h43m ---------------------------------------------------------------- Praveen Chaudhary (1): Allow user to set metric on default route learned via Router Advertisement. Documentation/networking/ip-sysctl.rst | 8 ++++++++ include/linux/ipv6.h | 1 + include/net/ip6_route.h | 3 ++- include/uapi/linux/ipv6.h | 1 + include/uapi/linux/sysctl.h | 1 + net/ipv6/addrconf.c | 10 ++++++++++ net/ipv6/ndisc.c | 15 +++++++++++---- net/ipv6/route.c | 8 +++++--- 8 files changed, 39 insertions(+), 8 deletions(-) -- 2.7.4