Dumitru Ceara <[email protected]> writes:

> Upstream commit:
>     commit 8aa7b526dc0b5dbf40c1b834d76a667ad672a410
>     Author: Dumitru Ceara <[email protected]>
>     Date:   Wed Oct 7 17:48:03 2020 +0200
>
>     openvswitch: handle DNAT tuple collision
>
>     With multiple DNAT rules it's possible that after destination
>     translation the resulting tuples collide.
>
>     For example, two openvswitch flows:
>     nw_dst=10.0.0.10,tp_dst=10, 
> actions=ct(commit,table=2,nat(dst=20.0.0.1:20))
>     nw_dst=10.0.0.20,tp_dst=10, 
> actions=ct(commit,table=2,nat(dst=20.0.0.1:20))
>
>     Assuming two TCP clients initiating the following connections:
>     10.0.0.10:5000->10.0.0.10:10
>     10.0.0.10:5000->10.0.0.20:10
>
>     Both tuples would translate to 10.0.0.10:5000->20.0.0.1:20 causing
>     nf_conntrack_confirm() to fail because of tuple collision.
>
>     Netfilter handles this case by allocating a null binding for SNAT at
>     egress by default.  Perform the same operation in openvswitch for DNAT
>     if no explicit SNAT is requested by the user and allocate a null binding
>     for SNAT for packets in the "original" direction.
>
>     Reported-at: https://bugzilla.redhat.com/1877128
>     Suggested-by: Florian Westphal <[email protected]>
>     Fixes: 05752523e565 ("openvswitch: Interface with NAT.")
>     Signed-off-by: Dumitru Ceara <[email protected]>
>     Signed-off-by: Jakub Kicinski <[email protected]>
>
> Fixes: f8f97cdce9ad ("datapath: Interface with NAT.")
> Signed-off-by: Dumitru Ceara <[email protected]>
> ---

Acked-by: Paolo Valerio <[email protected]>

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