[PATCH net-next 02/15] netfilter: flowtable: fix pmtu discovery in nf_flow_tunnel_ip6ip6_push()

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

nf_flow_tunnel_ip6ip6_push() invokes skb_scrub_packet() before updating
the PMTU. skb_scrub_packet() drops the skb dst, so
skb_dst_update_pmtu_no_confirm() finds no dst and the PMTU update is
silently lost.

Move the PMTU update before skb_scrub_packet() so the inner route is
updated with the MTU advertised by the tunnel dst, as done in
ip6_tnl_xmit().

Fixes: 93cf357fa797 ("netfilter: flowtable: Add IP6IP6 tx sw acceleration")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 19cafae748ab..644e70fd6773 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -699,10 +699,10 @@ static int nf_flow_tunnel_ip6_push(struct net *net, struct sk_buff *skb,
 	if (err)
 		return err;
 
-	skb_scrub_packet(skb, true);
 	mtu = dst_mtu(dst) - sizeof(*ip6h);
 	mtu = max(mtu, IPV6_MIN_MTU);
 	skb_dst_update_pmtu_no_confirm(skb, mtu);
+	skb_scrub_packet(skb, true);
 
 	skb_push(skb, sizeof(*ip6h));
 	skb_reset_network_header(skb);
-- 
2.47.3