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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2962FC4332F for ; Sun, 23 Jan 2022 00:15:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235588AbiAWAPp (ORCPT ); Sat, 22 Jan 2022 19:15:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235477AbiAWAO1 (ORCPT ); Sat, 22 Jan 2022 19:14:27 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D309C061788; Sat, 22 Jan 2022 16:13:11 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1D6E760F9F; Sun, 23 Jan 2022 00:13:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FBB4C340EA; Sun, 23 Jan 2022 00:13:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642896790; bh=8YhMF9n/5Mxn8xZsLWfMDxc71WSqOIyTuusNeOqsYI8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g83bsyQNelBe5K9ZZFcMDKPiv8LlulXVQ9DL0ieSZVuXVTaXIy2CxainZGXXJQ/pF 2vfb9P1/sJ+V981uf1yLbESyj134rNxydJPaN07+y/J/xS3Du93xokPYhbvPmCdZMX Eb9B2qrfIF+JLzrw91xGTFvV+nRP/aUIrff98EcbQinG25aKU7p06RRJCL1DadLW4g APavZ7liuKMbTdfDhVke0D7O49NhxPVFI4SKioVaTBlvQJvL21SRJGOUqQY9SPg+FH dfS7FaWBLhpwjziRhfKm1F72ZP5V8zuOUGArP7hGZpBxXPVAJoqGuzAH6vs8nvIzFT uBQOfccoDzNig== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ignat Korchagin , Amir Razmjou , David Ahern , Jakub Kicinski , Sasha Levin , davem@davemloft.net, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 3/9] sit: allow encapsulated IPv6 traffic to be delivered locally Date: Sat, 22 Jan 2022 19:12:52 -0500 Message-Id: <20220123001258.2460594-3-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220123001258.2460594-1-sashal@kernel.org> References: <20220123001258.2460594-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ignat Korchagin [ Upstream commit ed6ae5ca437d9d238117d90e95f7f2cc27da1b31 ] While experimenting with FOU encapsulation Amir noticed that encapsulated IPv6 traffic fails to be delivered, if the peer IP address is configured locally. It can be easily verified by creating a sit interface like below: $ sudo ip link add name fou_test type sit remote 127.0.0.1 encap fou encap-sport auto encap-dport 1111 $ sudo ip link set fou_test up and sending some IPv4 and IPv6 traffic to it $ ping -I fou_test -c 1 1.1.1.1 $ ping6 -I fou_test -c 1 fe80::d0b0:dfff:fe4c:fcbc "tcpdump -i any udp dst port 1111" will confirm that only the first IPv4 ping was encapsulated and attempted to be delivered. This seems like a limitation: for example, in a cloud environment the "peer" service may be arbitrarily scheduled on any server within the cluster, where all nodes are trying to send encapsulated traffic. And the unlucky node will not be able to. Moreover, delivering encapsulated IPv4 traffic locally is allowed. But I may not have all the context about this restriction and this code predates the observable git history. Reported-by: Amir Razmjou Signed-off-by: Ignat Korchagin Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20220107123842.211335-1-ignat@cloudflare.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/sit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index bab0e99f6e356..db098d3f9d6fc 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -949,7 +949,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr); } - if (rt->rt_type != RTN_UNICAST) { + if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) { ip_rt_put(rt); dev->stats.tx_carrier_errors++; goto tx_error_icmp; -- 2.34.1