[ovs-dev] northd: Avoid snat on reply packets for dgw

From: shylou <liuxie_11@163.com>

OVN had fix the issue[1] that avoid snat on reply packets for
gateway router. It is also needed to be dealt with for dgw.

[1]https://github.com/ovn-org/ovn/commit/8b3e1afc30

Signed-off-by: Xie Liu <liushyshy@gmail.com>
---
 northd/northd.c     |  4 ++++
 tests/ovn-northd.at | 56 ++++++++++++++++++++++-----------------------
 tests/ovn.at        |  4 ++--
 3 files changed, 34 insertions(+), 30 deletions(-)

On 9/12/23 13:57, liuxie_11@163.com wrote:
> From: shylou <liuxie_11@163.com>
> 
> OVN had fix the issue[1] that avoid snat on reply packets for
> gateway router. It is also needed to be dealt with for dgw.
> 
> [1]https://github.com/ovn-org/ovn/commit/8b3e1afc30
> 
> Signed-off-by: Xie Liu <liushyshy@gmail.com>
> ---

Hi, Xie Liu,

Sorry for taking long to review this patch.

>  northd/northd.c     |  4 ++++
>  tests/ovn-northd.at | 56 ++++++++++++++++++++++-----------------------
>  tests/ovn.at        |  4 ++--
>  3 files changed, 34 insertions(+), 30 deletions(-)
> 
> diff --git a/northd/northd.c b/northd/northd.c
> index 3eaa43f07..91a6e3f79 100644
> --- a/northd/northd.c
> +++ b/northd/northd.c
> @@ -14648,6 +14648,8 @@ build_lrouter_out_snat_in_czone_flow(struct hmap *lflows,

For context, the condition here is (the same as for the second chunk of
the diff):

if (distributed_nat) {
...

>                        ETH_ADDR_ARGS(mac));
>          ds_put_format(&zone_actions, "eth.src = "ETH_ADDR_FMT"; ",
>                        ETH_ADDR_ARGS(mac));
> +    } else {
> +        ds_put_format(match, " && (!ct.trk || !ct.rpl)");
>      }
>  
>      ds_put_cstr(&zone_actions, REGBIT_DST_NAT_IP_LOCAL" = 0; ");
> @@ -14706,6 +14708,8 @@ build_lrouter_out_snat_flow(struct hmap *lflows, struct ovn_datapath *od,
>          if (distributed_nat) {
>              ds_put_format(actions, "eth.src = "ETH_ADDR_FMT"; ",
>                            ETH_ADDR_ARGS(mac));
> +        } else {
> +            ds_put_format(match, " && (!ct.trk || !ct.rpl)");
>          }
>      } else {

I'm wondering why do we need to ski[ the case with "dnat_and_snat" and
logical_port and external_mac set.  Can't we just move the new line
outside the "if (distributed_nat)"?

Thanks,
Dumitru

>          /* Gateway router. */
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index 23dbe111f..ce3de2048 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -1100,7 +1100,7 @@ AT_CAPTURE_FILE([crflows])
>  AT_CHECK([grep -e "lr_out_snat" drflows | sed 's/table=../table=??/' | sort], [0], [dnl
>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range), action=(ct_snat(172.16.1.1);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.1);)
>  ])
>  
>  AT_CHECK([grep -e "lr_out_snat" crflows | sed 's/table=../table=??/' | sort], [0], [dnl
> @@ -1130,7 +1130,7 @@ AT_CAPTURE_FILE([crflows2])
>  AT_CHECK([grep -e "lr_out_snat" drflows2 | sed 's/table=../table=??/' | sort], [0], [dnl
>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.1);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.1);)
>    table=??(lr_out_snat        ), priority=163  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $disallowed_range), action=(next;)
>  ])
>  
> @@ -1159,7 +1159,7 @@ AT_CAPTURE_FILE([crflows2])
>  AT_CHECK([grep -e "lr_out_snat" drflows3 | sed 's/table=../table=??/' | sort], [0], [dnl
>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range), action=(ct_snat(172.16.1.2);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.2);)
>  ])
>  
>  AT_CHECK([grep -e "lr_out_snat" crflows3 | sed 's/table=../table=??/' | sort], [0], [dnl
> @@ -1186,7 +1186,7 @@ AT_CAPTURE_FILE([crflows2])
>  AT_CHECK([grep -e "lr_out_snat" drflows4 | sed 's/table=../table=??/' | sort], [0], [dnl
>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.2);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.2);)
>    table=??(lr_out_snat        ), priority=163  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $disallowed_range), action=(next;)
>  ])
>  
> @@ -5352,12 +5352,12 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.20);)
> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>  ])
>  
>  # Separate zones for DGP
> @@ -5400,9 +5400,9 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.20);)
>  ])
>  
>  # Associate load balancer to lr0
> @@ -5482,12 +5482,12 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.20);)
> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>  ])
>  
>  # Separate zones for DGP
> @@ -5548,9 +5548,9 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.10);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.30);)
> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.20);)
> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.10);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.30);)
> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.20);)
>  ])
>  
>  # Make the logical router as Gateway router
> @@ -7340,9 +7340,9 @@ AT_CHECK([grep lr_in_unsnat lrflows | grep ct_snat | sed 's/table=../table=??/'
>  ])
>  
>  AT_CHECK([grep lr_out_snat lrflows | grep ct_snat | sed 's/table=../table=??/' | sort], [0], [dnl
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.10);)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2")), action=(ct_snat(10.0.0.10);)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3")), action=(ct_snat(192.168.0.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2") && (!ct.trk || !ct.rpl)), action=(ct_snat(10.0.0.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3") && (!ct.trk || !ct.rpl)), action=(ct_snat(192.168.0.10);)
>  ])
>  
>  check ovn-nbctl --wait=sb lr-nat-del DR snat 20.0.0.10
> @@ -7416,9 +7416,9 @@ AT_CHECK([grep lr_in_unsnat lrflows | grep ct_snat | sed 's/table=../table=??/'
>  ])
>  
>  AT_CHECK([grep lr_out_snat lrflows | grep ct_snat | sed 's/table=../table=??/' | sort], [0], [dnl
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.10);)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2")), action=(ct_snat(10.0.0.10);)
> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3")), action=(ct_snat(192.168.0.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2") && (!ct.trk || !ct.rpl)), action=(ct_snat(10.0.0.10);)
> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3") && (!ct.trk || !ct.rpl)), action=(ct_snat(192.168.0.10);)
>  ])
>  
>  AT_CHECK([grep lr_in_dnat lrflows | grep ct_dnat | sed 's/table=../table=??/' | sort], [0], [dnl
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 2576a659b..79c729bc6 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -34453,7 +34453,7 @@ dnat_zone=$(ovs-ofctl dump-flows br-int table=$DNAT_TABLE,metadata=0x${lr0_dp_ke
>  if test -n "$dnat_zone"; then
>    dnat_zone=${dnat_zone::-1}
>  fi
> -snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep -o zone=.*, | cut -d '=' -f 2)
> +snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep ct_state=-trk | grep -o zone=.*, | cut -d '=' -f 2)
>  if test -n "$snat_zone"; then
>    snat_zone=${snat_zone::-1}
>  fi
> @@ -34470,7 +34470,7 @@ dnat_zone=$(ovs-ofctl dump-flows br-int table=$DNAT_TABLE,metadata=0x${lr0_dp_ke
>  if test -n "$dnat_zone"; then
>    dnat_zone=${dnat_zone::-1}
>  fi
> -snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep -o zone=.*, | cut -d '=' -f 2)
> +snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep ct_state=-trk | grep -o zone=.*, | cut -d '=' -f 2)
>  if test -n "$snat_zone"; then
>    snat_zone=${snat_zone::-1}
>  fi

>On 9/12/23 13:57, liuxie_11@163.com wrote:
>> From: shylou <liuxie_11@163.com>
>> 
>> OVN had fix the issue[1] that avoid snat on reply packets for
>> gateway router. It is also needed to be dealt with for dgw.
>> 
>> [1]https://github.com/ovn-org/ovn/commit/8b3e1afc30
>> 
>> Signed-off-by: Xie Liu <liushyshy@gmail.com>
>> ---
>
>Hi, Xie Liu,
>
>Sorry for taking long to review this patch.
>
>>  northd/northd.c     |  4 ++++
>>  tests/ovn-northd.at | 56 ++++++++++++++++++++++-----------------------
>>  tests/ovn.at        |  4 ++--
>>  3 files changed, 34 insertions(+), 30 deletions(-)
>> 
>> diff --git a/northd/northd.c b/northd/northd.c
>> index 3eaa43f07..91a6e3f79 100644
>> --- a/northd/northd.c
>> +++ b/northd/northd.c
>> @@ -14648,6 +14648,8 @@ build_lrouter_out_snat_in_czone_flow(struct hmap *lflows,
>
>For context, the condition here is (the same as for the second chunk of
>the diff):
>
>if (distributed_nat) {
>...
>
>>                        ETH_ADDR_ARGS(mac));
>>          ds_put_format(&zone_actions, "eth.src = "ETH_ADDR_FMT"; ",
>>                        ETH_ADDR_ARGS(mac));
>> +    } else {
>> +        ds_put_format(match, " && (!ct.trk || !ct.rpl)");
>>      }
>>  
>>      ds_put_cstr(&zone_actions, REGBIT_DST_NAT_IP_LOCAL" = 0; ");
>> @@ -14706,6 +14708,8 @@ build_lrouter_out_snat_flow(struct hmap *lflows, struct ovn_datapath *od,
>>          if (distributed_nat) {
>>              ds_put_format(actions, "eth.src = "ETH_ADDR_FMT"; ",
>>                            ETH_ADDR_ARGS(mac));
>> +        } else {
>> +            ds_put_format(match, " && (!ct.trk || !ct.rpl)");
>>          }
>>      } else {
>
>I'm wondering why do we need to ski[ the case with "dnat_and_snat" and
>logical_port and external_mac set.  Can't we just move the new line
>outside the "if (distributed_nat)"?
>
>Thanks,
>Dumitru
Hi Dumitru,
Thanks for your review, let me upgrade it in next patch with your advices.
>
>>          /* Gateway router. */
>> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
>> index 23dbe111f..ce3de2048 100644
>> --- a/tests/ovn-northd.at
>> +++ b/tests/ovn-northd.at
>> @@ -1100,7 +1100,7 @@ AT_CAPTURE_FILE([crflows])
>>  AT_CHECK([grep -e "lr_out_snat" drflows | sed 's/table=../table=??/' | sort], [0], [dnl
>>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range), action=(ct_snat(172.16.1.1);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.1);)
>>  ])
>>  
>>  AT_CHECK([grep -e "lr_out_snat" crflows | sed 's/table=../table=??/' | sort], [0], [dnl
>> @@ -1130,7 +1130,7 @@ AT_CAPTURE_FILE([crflows2])
>>  AT_CHECK([grep -e "lr_out_snat" drflows2 | sed 's/table=../table=??/' | sort], [0], [dnl
>>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.1);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.1);)
>>    table=??(lr_out_snat        ), priority=163  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $disallowed_range), action=(next;)
>>  ])
>>  
>> @@ -1159,7 +1159,7 @@ AT_CAPTURE_FILE([crflows2])
>>  AT_CHECK([grep -e "lr_out_snat" drflows3 | sed 's/table=../table=??/' | sort], [0], [dnl
>>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range), action=(ct_snat(172.16.1.2);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $allowed_range && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.2);)
>>  ])
>>  
>>  AT_CHECK([grep -e "lr_out_snat" crflows3 | sed 's/table=../table=??/' | sort], [0], [dnl
>> @@ -1186,7 +1186,7 @@ AT_CAPTURE_FILE([crflows2])
>>  AT_CHECK([grep -e "lr_out_snat" drflows4 | sed 's/table=../table=??/' | sort], [0], [dnl
>>    table=??(lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=??(lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.2);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.2);)
>>    table=??(lr_out_snat        ), priority=163  , match=(ip && ip4.src == 50.0.0.11 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && ip4.dst == $disallowed_range), action=(next;)
>>  ])
>>  
>> @@ -5352,12 +5352,12 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.20);)
>> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>>  ])
>>  
>>  # Separate zones for DGP
>> @@ -5400,9 +5400,9 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.20);)
>>  ])
>>  
>>  # Associate load balancer to lr0
>> @@ -5482,12 +5482,12 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat_in_czone(172.168.0.20);)
>> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=154  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat_in_czone(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=162  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl) && reg9[[4]] == 1), action=(reg9[[4]] = 0; ct_snat(172.168.0.20);)
>>  ])
>>  
>>  # Separate zones for DGP
>> @@ -5548,9 +5548,9 @@ AT_CHECK([grep "lr_out_post_undnat" lr0flows | sed 's/table=./table=?/' | sort],
>>  AT_CHECK([grep "lr_out_snat" lr0flows | sed 's/table=./table=?/' | sort], [0], [dnl
>>    table=? (lr_out_snat        ), priority=0    , match=(1), action=(next;)
>>    table=? (lr_out_snat        ), priority=120  , match=(nd_ns), action=(next;)
>> -  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.10);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.30);)
>> -  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public")), action=(ct_snat(172.168.0.20);)
>> +  table=? (lr_out_snat        ), priority=153  , match=(ip && ip4.src == 10.0.0.0/24 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.10);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.10 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.30);)
>> +  table=? (lr_out_snat        ), priority=161  , match=(ip && ip4.src == 10.0.0.3 && outport == "lr0-public" && is_chassis_resident("cr-lr0-public") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.168.0.20);)
>>  ])
>>  
>>  # Make the logical router as Gateway router
>> @@ -7340,9 +7340,9 @@ AT_CHECK([grep lr_in_unsnat lrflows | grep ct_snat | sed 's/table=../table=??/'
>>  ])
>>  
>>  AT_CHECK([grep lr_out_snat lrflows | grep ct_snat | sed 's/table=../table=??/' | sort], [0], [dnl
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.10);)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2")), action=(ct_snat(10.0.0.10);)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3")), action=(ct_snat(192.168.0.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2") && (!ct.trk || !ct.rpl)), action=(ct_snat(10.0.0.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3") && (!ct.trk || !ct.rpl)), action=(ct_snat(192.168.0.10);)
>>  ])
>>  
>>  check ovn-nbctl --wait=sb lr-nat-del DR snat 20.0.0.10
>> @@ -7416,9 +7416,9 @@ AT_CHECK([grep lr_in_unsnat lrflows | grep ct_snat | sed 's/table=../table=??/'
>>  ])
>>  
>>  AT_CHECK([grep lr_out_snat lrflows | grep ct_snat | sed 's/table=../table=??/' | sort], [0], [dnl
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1")), action=(ct_snat(172.16.1.10);)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2")), action=(ct_snat(10.0.0.10);)
>> -  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3")), action=(ct_snat(192.168.0.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S1" && is_chassis_resident("cr-DR-S1") && (!ct.trk || !ct.rpl)), action=(ct_snat(172.16.1.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S2" && is_chassis_resident("cr-DR-S2") && (!ct.trk || !ct.rpl)), action=(ct_snat(10.0.0.10);)
>> +  table=??(lr_out_snat        ), priority=161  , match=(ip && ip4.src == 20.0.0.10 && outport == "DR-S3" && is_chassis_resident("cr-DR-S3") && (!ct.trk || !ct.rpl)), action=(ct_snat(192.168.0.10);)
>>  ])
>>  
>>  AT_CHECK([grep lr_in_dnat lrflows | grep ct_dnat | sed 's/table=../table=??/' | sort], [0], [dnl
>> diff --git a/tests/ovn.at b/tests/ovn.at
>> index 2576a659b..79c729bc6 100644
>> --- a/tests/ovn.at
>> +++ b/tests/ovn.at
>> @@ -34453,7 +34453,7 @@ dnat_zone=$(ovs-ofctl dump-flows br-int table=$DNAT_TABLE,metadata=0x${lr0_dp_ke
>>  if test -n "$dnat_zone"; then
>>    dnat_zone=${dnat_zone::-1}
>>  fi
>> -snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep -o zone=.*, | cut -d '=' -f 2)
>> +snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep ct_state=-trk | grep -o zone=.*, | cut -d '=' -f 2)
>>  if test -n "$snat_zone"; then
>>    snat_zone=${snat_zone::-1}
>>  fi
>> @@ -34470,7 +34470,7 @@ dnat_zone=$(ovs-ofctl dump-flows br-int table=$DNAT_TABLE,metadata=0x${lr0_dp_ke
>>  if test -n "$dnat_zone"; then
>>    dnat_zone=${dnat_zone::-1}
>>  fi
>> -snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep -o zone=.*, | cut -d '=' -f 2)
>> +snat_zone=$(ovs-ofctl dump-flows br-int table=$SNAT_TABLE,metadata=0x${lr0_dp_key} | grep priority=153 | grep ct_state=-trk | grep -o zone=.*, | cut -d '=' -f 2)
>>  if test -n "$snat_zone"; then
>>    snat_zone=${snat_zone::-1}
>>  fi