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=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 80119C2B9F4 for ; Fri, 25 Jun 2021 15:27:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DD9461948 for ; Fri, 25 Jun 2021 15:27:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229982AbhFYPaD (ORCPT ); Fri, 25 Jun 2021 11:30:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:34292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229586AbhFYPaC (ORCPT ); Fri, 25 Jun 2021 11:30:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EA5116193F; Fri, 25 Jun 2021 15:27:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624634861; bh=lwR2g6gRk+aJ4xVmniL5GuaewpPGjDCLk9yE/FrMrt8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BTsUejnuJPzvuMHBjXJuP3F/q+Vl24rM4YE4aW0cU8bcpBo+uxdMY+JzNyfJhPjV5 OSjMNQ6dyGuNYCJHeWOxWyScxTD90ynDFjAX3hI2/cJ3xjt+XraKFhUDf6e1mg9M1C cb5+2sm6RVG4/smYydQWBfnZVXKu2LM/tJ5WkJMLcfVRvz2QgwHTzgL1XFi/ZE/HXy 7XMztvarBt0LrP1xL5aRgd0RxHXB7wiGjHorXggBS6LWOZD/WGVn/q5RPjV0Rqno9r isK02Y1xwzHhG959IYkj/DsqiOzZZCbRFcO/ej0vf76hmHQEeNmtzookjoxNHR2D8t MKex1lkplbZ4A== Received: by pali.im (Postfix) id 9D34FA7D; Fri, 25 Jun 2021 17:27:37 +0200 (CEST) Date: Fri, 25 Jun 2021 17:27:37 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: Nicolas Dichtel Cc: Marek =?utf-8?B?QmVow7pu?= , netdev@vger.kernel.org, "David S. Miller" , Jakub Kicinski , Alexey Kuznetsov , Hideaki YOSHIFUJI , linux-kernel@vger.kernel.org, Andrew Lunn , Russell King , Stephen Hemminger , Phil Sutter Subject: Re: Issues during assigning addresses on point to point interfaces Message-ID: <20210625152737.6gslduccvguyrr77@pali> References: <20210606151008.7dwx5ukrlvxt4t3k@pali> <20210624124545.2b170258@dellmb> <20210625084031.c33yovvximtabmf4@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Friday 25 June 2021 17:06:21 Nicolas Dichtel wrote: > Le 25/06/2021 à 10:40, Pali Rohár a écrit : > > On Thursday 24 June 2021 14:57:41 Nicolas Dichtel wrote: > >> Le 24/06/2021 à 12:45, Marek Behún a écrit : > >>> On Sun, 6 Jun 2021 17:10:08 +0200 > >>> Pali Rohár wrote: > >>> > >>>> Hello! > >>>> > >>>> Seems that there is a bug during assigning IP addresses on point to > >>>> point interfaces. > >>>> > >>>> Assigning just one local address works fine: > >>>> > >>>> ip address add fe80::6 dev ppp1 --> inet6 fe80::6/128 scope link > >>>> > >>>> Assigning both local and remote peer address also works fine: > >>>> > >>>> ip address add fe80::7 peer fe80::8 dev ppp1 ---> inet6 fe80::7 > >>>> peer fe80::8/128 scope link > >>>> > >>>> But trying to assign just remote peer address does not work. Moreover > >>>> "ip address" call does not fail, it returns zero but instead of > >>>> setting remote peer address, it sets local address: > >>>> > >>>> ip address add peer fe80::5 dev ppp1 --> inet6 fe80::5/128 scope > >>>> link > >>>> > >>> > >>> Adding some other people to Cc in order to get their opinions. > >>> > >>> It seems this bug is there from the beginning, from commit > >>> caeaba79009c2 ("ipv6: add support of peer address") > >>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=caeaba79009c2 > >>> > >>> Maybe some older user-space utilities use IFA_ADDRESS instead of > >>> IFA_LOCAL, and this was done in order to be compatible with them? > >> If I remember well, there was an issue in the uAPI. > >> IFA_LOCAL is supposed to be the address of the interface and IFA_ADDRESS is > >> supposed to be the endpoint of a point-to-point interface. > >> However, in case of IPv6, it was not the case. In netlink messages generated by > >> the kernel, IFA_ADDRESS was used instead of IFA_LOCAL. > >> The patch tried to keep the backward compatibility and the symmetry between msg > >> from userland and notification from the kernel. > > > > Hello Nicolas! > > > > See my original email where I put also rtnetlink packets (how strace see > > them). Seems that there is a bug in handling them (or bug in iproute2) > > as setting just peer (remote) IPv6 address is ignored: > > https://lore.kernel.org/netdev/20210606151008.7dwx5ukrlvxt4t3k@pali/ > > > > Do you have any idea if this is affected by that "issue in the uAPI"? > > And what is the way how to fix it? > What about forcing IFA_LOCAL address to :: in your case? It does not work. ip address returns error: $ sudo ip address add :: peer fe80::8 dev ppp0 RTNETLINK answers: Cannot assign requested address Here is strace output: sendmsg(3, { msg_name={ sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000 }, msg_namelen=12, msg_iov=[{ iov_base={ { len=64, type=RTM_NEWADDR, flags=NLM_F_REQUEST|NLM_F_ACK|NLM_F_EXCL|NLM_F_CREATE, seq=1624633811, pid=0 }, { ifa_family=AF_INET6, ifa_prefixlen=128, ifa_flags=0, ifa_scope=RT_SCOPE_UNIVERSE, ifa_index=if_nametoindex("ppp0") }, [ { { nla_len=20, nla_type=IFA_LOCAL }, inet_pton(AF_INET6, "::") }, { { nla_len=20, nla_type=IFA_ADDRESS }, inet_pton(AF_INET6, "fe80::8") } ] }, iov_len=64 }], msg_iovlen=1, msg_controllen=0, msg_flags=0 }, 0) = 64 recvmsg(3, { msg_name={ sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000 }, msg_namelen=12, msg_iov=[{ iov_base=NULL, iov_len=0 }], msg_iovlen=1, msg_controllen=0, msg_flags=MSG_TRUNC }, MSG_PEEK|MSG_TRUNC) = 84 recvmsg(3, { msg_name={ sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000 }, msg_namelen=12, msg_iov=[{ iov_base={ { len=84, type=NLMSG_ERROR, flags=0, seq=1624633811, pid=3698 }, { error=-EADDRNOTAVAIL, msg={ { len=64, type=RTM_NEWADDR, flags=NLM_F_REQUEST|NLM_F_ACK|NLM_F_EXCL|NLM_F_CREATE, seq=1624633811, pid=0 }, { ifa_family=AF_INET6, ifa_prefixlen=128, ifa_flags=0, ifa_scope=RT_SCOPE_UNIVERSE, ifa_index=if_nametoindex("ppp0") }, [ { { nla_len=20, nla_type=IFA_LOCAL }, inet_pton(AF_INET6, "::") }, { { nla_len=20, nla_type=IFA_ADDRESS }, inet_pton(AF_INET6, "fe80::8") } ] } } }, iov_len=84 }], msg_iovlen=1, msg_controllen=0, msg_flags=0 }, 0) = 84