vrf: T6097: Fix for veth pair in different VRFS

[hedrok]

Change summary

When veth interface pair is in different VRFS and there is a firewall rule, ct original zone is set for a VRF, which blocks packets somewhy.

Changing to ct zone (for both directions) fixes this.

Types of changes

• Bug fix (non-breaking change which fixes an issue) (hopefully non-breaking)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T6097

Related PR(s)

How to test / Smoketest result

configure
set firewall ipv6 input filter default-action accept
set interfaces virtual-ethernet veth0 address 2001:db8::/127
set interfaces virtual-ethernet veth0 peer-name veth1
set interfaces virtual-ethernet veth1 address 2001:db8::1/127
set interfaces virtual-ethernet veth1 peer-name veth0
set interfaces virtual-ethernet veth1 vrf red
set vrf name red table 1000
commit

# Works:
run ping 2001:db8::1 source-address 2001:db8::

set firewall ipv6 input filter rule 10 action accept 
set firewall ipv6 input filter rule 10 state established 
commit

# Doesn't work:
run ping 2001:db8::1 source-address 2001:db8::

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

👍
No issues in PR Title / Commit Title

[github-actions]

CI integration ❌ failed!

Details

CI logs

• CLI Smoketests (no interfaces) ❌ failed
• CLI Smoketests VPP 👍 passed
• CLI Smoketests (interfaces only) 👍 passed
• Config tests 👍 passed
• Config tests VPP 👍 passed
• RAID1 tests 👍 passed
• TPM tests 👍 passed

[hedrok]

Failed test:

2025-11-27T10:59:03.5121777Z DEBUG - Running Testcase: /usr/libexec/vyos/tests/smoke/cli/test_protocols_bgp.py
2025-11-27T11:03:29.9029325Z DEBUG - test_bgp_99_bmp (__main__.TestProtocolsBGP.test_bgp_99_bmp) ... FAIL

Most probably has no connection to changes.