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=-6.6 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,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 D3101C433DF for ; Mon, 19 Oct 2020 03:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86F43206E9 for ; Mon, 19 Oct 2020 03:55:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bZKO7VCR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731715AbgJSDz1 (ORCPT ); Sun, 18 Oct 2020 23:55:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731306AbgJSDz1 (ORCPT ); Sun, 18 Oct 2020 23:55:27 -0400 Received: from mail-lj1-x243.google.com (mail-lj1-x243.google.com [IPv6:2a00:1450:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC75FC061755; Sun, 18 Oct 2020 20:55:26 -0700 (PDT) Received: by mail-lj1-x243.google.com with SMTP id i2so10390615ljg.4; Sun, 18 Oct 2020 20:55:26 -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=JGRhD4PEJkPED9SetcvHdpE4f5nhMr/c5YW65Q6YUlE=; b=bZKO7VCR4I4+1wjrFBmZMGZJByH62WFATFg4GFd9UJ3PoVJc61jcpktT837bgYflPH pPbcHo/EoNXIcaELhtfthGYs14cwBs5X7iWwQqfn4yTz9kT75biUXGTa+V491Jso3uOk AzounLT1cQiKiacmbmCeeQnjWVKEw5uehZnaumjcRWC7wPERdZ5G1RmwBnU4Z1MBBMjR 2ZydHN7DYREUresYmd7CFGxSwrVswiBYIo60LsaJqBW6MolZvXx0gEAnISn5ChulmMWD D2HSB6kazz42AFlYeKiy5n9gSFh0JC7jJgRrU+opKX9e/soEbGOQdsGJnpuR0XWbBg8E tTqg== 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=JGRhD4PEJkPED9SetcvHdpE4f5nhMr/c5YW65Q6YUlE=; b=o4l25ftcfRf+7Ac4+HOYlxcMTpnXo8zBi7XsK7O+I8JCPs9Ss0B8jKkpSjdYn9Zq7f rWdPFwkg9vCwhN0O1KXgcSbppBjgkLSjl4GgSSkOGwJBFsExbtKjuUhAVxRy8FX0FE1F rKuXNDeDcylGKEmtxHCxBUtz1RFa5Q7AozJpc1nr7lARFtv0gvZdzSlbAPsW1GZIq5Zz OXNMLLF7nJbAn0On9BcV8EqgpXG87Vm8UZYgE7pTs273xe0g0W2R3ShOuU62RX0LpJXE qRlDHsTV78nzg5ECWtlOcWKC8HWp7VQ4ENGXHFW4GMzIKREYYTNHHZmRTA76/DNmj8cH zSYg== X-Gm-Message-State: AOAM530xanLmumm7nPiSs1XCmN7GzDN0E1X3ltsLHXIu8QHPjZTKt8y3 aSH03Bmsr2cx8bzIxZzAGZG2I2lghn94k9EN20PFJmx/cUo6 X-Google-Smtp-Source: ABdhPJyHm+0O32JklLtr5FJF0K/1T/HeWFTvyT0kyXME7dMRKYtreYmTbSuK6mwqOj05evXptiwtcym6EZ9dCEU7hsE= X-Received: by 2002:a2e:8e72:: with SMTP id t18mr4948814ljk.445.1603079725084; Sun, 18 Oct 2020 20:55:25 -0700 (PDT) MIME-Version: 1.0 References: <20201015082119.68287-1-rejithomas@juniper.net> <20201018160147.6b3c940a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20201018160147.6b3c940a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Reji Thomas Date: Mon, 19 Oct 2020 09:25:12 +0530 Message-ID: Subject: Re: [PATCH v2] IPv6: sr: Fix End.X nexthop to use oif. To: Jakub Kicinski Cc: Reji Thomas , davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel test robot , Mathieu Xhonneux , David Lebrun Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, Please find my replies inline below. Regards Reji On Mon, Oct 19, 2020 at 4:31 AM Jakub Kicinski wrote: > > On Thu, 15 Oct 2020 13:51:19 +0530 Reji Thomas wrote: > > Currently End.X action doesn't consider the outgoing interface > > while looking up the nexthop.This breaks packet path functionality > > specifically while using link local address as the End.X nexthop. > > The patch fixes this by enforcing End.X action to have both nh6 and > > oif and using oif in lookup.It seems this is a day one issue. > > > > Fixes: 140f04c33bbc ("ipv6: sr: implement several seg6local actions") > > Signed-off-by: Reji Thomas > > David, Mathiey - any comments? > > > @@ -239,6 +250,8 @@ static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt) > > static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt) > > { > > struct ipv6_sr_hdr *srh; > > + struct net_device *odev; > > + struct net *net = dev_net(skb->dev); > > Order longest to shortest. Sorry. Will fix it. > > > > > > srh = get_and_validate_srh(skb); > > if (!srh) > > @@ -246,7 +259,11 @@ static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt) > > > > advance_nextseg(srh, &ipv6_hdr(skb)->daddr); > > > > - seg6_lookup_nexthop(skb, &slwt->nh6, 0); > > + odev = dev_get_by_index_rcu(net, slwt->oif); > > + if (!odev) > > + goto drop; > > Are you doing this lookup just to make sure that oif exists? > Looks a little wasteful for fast path, but more importantly > it won't be backward compatible, right? See below.. > Please see reply below. > > + > > + seg6_strict_lookup_nexthop(skb, &slwt->nh6, odev->ifindex, 0); > > > > return dst_input(skb); > > > > > @@ -566,7 +583,8 @@ static struct seg6_action_desc seg6_action_table[] = { > > }, > > { > > .action = SEG6_LOCAL_ACTION_END_X, > > - .attrs = (1 << SEG6_LOCAL_NH6), > > + .attrs = ((1 << SEG6_LOCAL_NH6) | > > + (1 << SEG6_LOCAL_OIF)), > > .input = input_action_end_x, > > }, > > { > > If you set this parse_nla_action() will reject all > SEG6_LOCAL_ACTION_END_X without OIF. > > As you say the OIF is only required for using link local addresses, > so this change breaks perfectly legitimate configurations. > > Can we instead only warn about the missing OIF, and only do that when > nh is link local? > End.X is defined as an adjacency-sid and is used to select a specific link to a neighbor for both global and link-local addresses. The intention was to drop the packet even for global addresses if the route via the specific interface is not found. Alternatively(believe semantically correct for End.X definition) I could do a neighbor lookup for nexthop address over specific interface and send the packet out. > Also doesn't SEG6_LOCAL_ACTION_END_DX6 need a similar treatment? Yes. I will update the patch for End.DX6 based on the patch finalized for End.X.