From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fout-a6-smtp.messagingengine.com (fout-a6-smtp.messagingengine.com [103.168.172.149]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D8ED3431FF; Tue, 21 Oct 2025 15:56:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.149 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761062219; cv=none; b=pMELcuQALiZFln4FXYbcP2kccBxC7e1/zDe9FMlld5L3F7lFtkpDXIYhti/RdX/GRjVt2yI/xW8LGWThq+MgO5z2fB91V8QJ7EPTXyGfgi0oQdbBbgyd8XdlxeNmaAd9niYu+bst0wJGWI+n+Ja/K42NtTSLNRMfT/SHrsmb5Zs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761062219; c=relaxed/simple; bh=k+3GyVKvPrng59do5wtL6iKnaaTY7D3oNShC+ZnxHvY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E1ubPZrRYYAzGFALkPo3XwazKsKAK7Ri37/1mgLY5HoRT/zRPDh/JB8GmlSPzzBCZJWASiKomrx3HzA97m6uCHWVbdMe2ZTQW8ieCqvkOoN72CX2EDZo8VsR89Oq1o4n+8PPTzWIOc2x1Hgqw6I5qhwxViZgiUyhA8Ds5EfYChw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=idosch.org; spf=none smtp.mailfrom=idosch.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=m7rFIcep; arc=none smtp.client-ip=103.168.172.149 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=idosch.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=idosch.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="m7rFIcep" Received: from phl-compute-06.internal (phl-compute-06.internal [10.202.2.46]) by mailfout.phl.internal (Postfix) with ESMTP id 96E4BEC01E4; Tue, 21 Oct 2025 11:56:54 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-06.internal (MEProxy); Tue, 21 Oct 2025 11:56:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t= 1761062214; x=1761148614; bh=byUZFd3/ULJFsBc0eWzLiJYFp2wANAnzYMV PhIjh5lI=; b=m7rFIcepIqc+6/tV6SraQVonhWmLDebiNF7108dZrUcw0BkNv/V MBbPphflf4WEps66EItdkOybUd2EuNv+/JlIR/w9+uNSDy1JEUABh4ulOVFBRdZL dR6weaVqq3duqpNUi7dSLAbUtPaBq9/b//ukA3PTPibHrq1gQSPhvOdpMSQLEK/Z IrOI6liPBYRimcxfSjmJWbVRhP4O9he1hf6HZp7ZsYnQFAQoikTZeky/utdd2UGo +zhu4j+ejxqH0hvNpcWvLeWFrvZ3iCD35URl/3HEepVLXkaLIek7lwa/LZg4q8Ja PoLEa4tEfrzBvECj37aB+DUSdQRkt6F3FrA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggddugeduuddvucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucenucfjughrpeffhffvvefukfhfgggtuggjsehttdertd dttddvnecuhfhrohhmpefkughoucfutghhihhmmhgvlhcuoehiughoshgthhesihguohhs tghhrdhorhhgqeenucggtffrrghtthgvrhhnpedvudefveekheeugeeftddvveefgfduie efudeifefgleekheegleegjeejgeeghfenucevlhhushhtvghrufhiiigvpedtnecurfgr rhgrmhepmhgrihhlfhhrohhmpehiughoshgthhesihguohhstghhrdhorhhgpdhnsggprh gtphhtthhopeelpdhmohguvgepshhmthhpohhuthdprhgtphhtthhopehgrdhgohhllhgv rhesphhrohigmhhogidrtghomhdprhgtphhtthhopegurghvvghmsegurghvvghmlhhofh htrdhnvghtpdhrtghpthhtohepughsrghhvghrnheskhgvrhhnvghlrdhorhhgpdhrtghp thhtohepvgguuhhmrgiivghtsehgohhoghhlvgdrtghomhdprhgtphhtthhopehkuhgsrg eskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepphgrsggvnhhisehrvgguhhgrthdrtgho mhdprhgtphhtthhopehhohhrmhhssehkvghrnhgvlhdrohhrghdprhgtphhtthhopehnvg htuggvvhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhk vghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrgh X-ME-Proxy: Feedback-ID: i494840e7:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 21 Oct 2025 11:56:53 -0400 (EDT) Date: Tue, 21 Oct 2025 18:56:51 +0300 From: Ido Schimmel To: g.goller@proxmox.com Cc: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Wrong source address selection in arp_solicit for forwarded packets Message-ID: References: <76z4ckbvjimtrf2foaislezs4vlru5upxn3i5ysu4au2m2pfei@slgxispho2iv> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <76z4ckbvjimtrf2foaislezs4vlru5upxn3i5ysu4au2m2pfei@slgxispho2iv> On Tue, Oct 21, 2025 at 02:31:51PM +0200, Gabriel Goller wrote: > Hmm I don't know how this would help? There is a link-local address set > on the interface, but we would have to add a ipv6 source address to the > arp packet which wouldn't be right? There are no ARP packets. Neighbour resolution is performed via IPv6 NA/NS messages. The script below [1] replicates your setup as I understand, but it uses IPv6 link-local addresses for the nexthops. [1] #!/bin/bash cleanup() { for i in {1..3}; do ip netns del node${i} &> /dev/null done } trap cleanup EXIT cleanup for i in {1..3}; do ip netns add node${i} ip netns exec node${i} sysctl -wq net.ipv4.conf.all.forwarding=1 ip netns exec node${i} sysctl -wq net.ipv4.conf.all.rp_filter=2 ip -n node${i} link set dev lo up ip -n node${i} link add name dummy up type dummy ip -n node${i} address add 10.0.1.${i}/32 dev dummy done ip -n node1 link add name veth1 type veth peer name veth2 netns node2 ip -n node2 link add name veth3 type veth peer name veth4 netns node3 ip -n node1 link set dev veth1 up ip -n node2 link set dev veth2 up ip -n node2 link set dev veth3 up ip -n node3 link set dev veth4 up ip -n node1 address add fe80::1/64 dev veth1 nodad ip -n node2 address add fe80::2/64 dev veth2 nodad ip -n node2 address add fe80::3/64 dev veth3 nodad ip -n node3 address add fe80::4/64 dev veth4 nodad ip -n node1 route add 10.0.1.2/32 src 10.0.1.1 nexthop via inet6 fe80::2 dev veth1 ip -n node1 route add 10.0.1.3/32 src 10.0.1.1 nexthop via inet6 fe80::2 dev veth1 ip -n node2 route add 10.0.1.1/32 src 10.0.1.2 nexthop via inet6 fe80::1 dev veth2 ip -n node2 route add 10.0.1.3/32 src 10.0.1.2 nexthop via inet6 fe80::4 dev veth3 ip -n node3 route add 10.0.1.1/32 src 10.0.1.3 nexthop via inet6 fe80::3 dev veth4 ip -n node3 route add 10.0.1.2/32 src 10.0.1.3 nexthop via inet6 fe80::3 dev veth4 ip netns exec node1 ping 10.0.1.3 -c 5 ip netns exec node1 ping 10.0.1.2 -c 5