From: Antoine Tenart atenart@kernel.org
[ Upstream commit 30a93d2b7d5a7cbb53ac19c9364a256d1aa6c08a ]
When the interface is part of a bridge or an Open vSwitch port and a packet exceed a PMTU estimate, an ICMP reply is sent to the sender. When using the external mode (collect metadata) the source and destination addresses are reversed, so that Open vSwitch can match the packet against an existing (reverse) flow.
But inverting the source and destination addresses in the shared ip_tunnel_info will make following packets of the flow to use a wrong destination address (packets will be tunnelled to itself), if the flow isn't updated. Which happens with Open vSwitch, until the flow times out.
Fixes this by uncloning the skb's ip_tunnel_info before inverting its source and destination addresses, so that the modification will only be made for the PTMU packet, not the following ones.
Fixes: fc68c99577cc ("vxlan: Support for PMTU discovery on directly bridged links") Tested-by: Eelco Chaudron echaudro@redhat.com Reviewed-by: Eelco Chaudron echaudro@redhat.com Signed-off-by: Antoine Tenart atenart@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/vxlan.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 50cb8f045a1e..d3b698d9e2e6 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2724,12 +2724,17 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, goto tx_error; } else if (err) { if (info) { + struct ip_tunnel_info *unclone; struct in_addr src, dst;
+ unclone = skb_tunnel_info_unclone(skb); + if (unlikely(!unclone)) + goto tx_error; + src = remote_ip.sin.sin_addr; dst = local_ip.sin.sin_addr; - info->key.u.ipv4.src = src.s_addr; - info->key.u.ipv4.dst = dst.s_addr; + unclone->key.u.ipv4.src = src.s_addr; + unclone->key.u.ipv4.dst = dst.s_addr; } vxlan_encap_bypass(skb, vxlan, vxlan, vni, false); dst_release(ndst); @@ -2780,12 +2785,17 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, goto tx_error; } else if (err) { if (info) { + struct ip_tunnel_info *unclone; struct in6_addr src, dst;
+ unclone = skb_tunnel_info_unclone(skb); + if (unlikely(!unclone)) + goto tx_error; + src = remote_ip.sin6.sin6_addr; dst = local_ip.sin6.sin6_addr; - info->key.u.ipv6.src = src; - info->key.u.ipv6.dst = dst; + unclone->key.u.ipv6.src = src; + unclone->key.u.ipv6.dst = dst; }
vxlan_encap_bypass(skb, vxlan, vxlan, vni, false);