From ab48ac052619329ceeeadbf9b0291cb1b72281a3 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 18 Oct 2018 21:25:07 +0200 Subject: [PATCH] ip6_tunnel: Fix encapsulation layout Commit b1a1b2bc49fd ("ip6_tun: Add infrastructure for doing encapsulation") added the ip6_tnl_encap() call in ip6_tnl_xmit(), before the call to ipv6_push_frag_opts() to append the IPv6 Tunnel Encapsulation Limit option (option 4, RFC 2473, par. 5.1) to the outer IPv6 header. As long as the option didn't actually end up in generated packets, this wasn't an issue. Then commit 9e183c130cac ("ip6_tunnel: Fix missing tunnel encapsulation limit option") fixed sending of this option, and the resulting layout, e.g. for FoU, is: .-------------------.------------.----------.-------------------.----- - - | Outer IPv6 Header | UDP header | Option 4 | Inner IPv6 Header | Payload '-------------------'------------'----------'-------------------'----- - - Needless to say, FoU and GUE (at least) won't work over IPv6. The option is appended by default, and I couldn't find a way to disable it with the current iproute2. Turn this into a more reasonable: .-------------------.----------.------------.-------------------.----- - - | Outer IPv6 Header | Option 4 | UDP header | Inner IPv6 Header | Payload '-------------------'----------'------------'-------------------'----- - - With this, and with c7125f96fd7b ("udp6: fix encap return code for resubmitting"), FoU and GUE work again over IPv6. Fixes: b1a1b2bc49fd ("ip6_tun: Add infrastructure for doing encapsulation") Signed-off-by: Stefano Brivio Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index a0b6932c3afd2..a9d06d4dd0578 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1184,11 +1184,6 @@ route_lookup: } skb_dst_set(skb, dst); - if (encap_limit >= 0) { - init_tel_txopt(&opt, encap_limit); - ipv6_push_frag_opts(skb, &opt.ops, &proto); - } - if (hop_limit == 0) { if (skb->protocol == htons(ETH_P_IP)) hop_limit = ip_hdr(skb)->ttl; @@ -1210,6 +1205,11 @@ route_lookup: if (err) return err; + if (encap_limit >= 0) { + init_tel_txopt(&opt, encap_limit); + ipv6_push_frag_opts(skb, &opt.ops, &proto); + } + skb_push(skb, sizeof(struct ipv6hdr)); skb_reset_network_header(skb); ipv6h = ipv6_hdr(skb); -- 2.39.5