Fix Static NAT/Port Forwarding when VM NIC is not the default

[sudo87]

Description

This PR intends to fix #8366

When CloudStack VR forwards traffic to a VM whose NIC is not the VM's default, the VM may reply via its default NIC (asymmetric routing). To force symmetric routing we SNAT the forwarded packet's source to the VR’s guest IP on the VM subnet so the VM replies on-link back to that VR interface. Also fix the port-forwarding SNAT to pick the correct VR guest IP for the VM's subnet

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

1. Deploy instance vm1 on network (net_1)
2. Create Isolated network (iso_2), attach NIC nic_2 from this to vm1
3. Acquire public_ip from iso_2 and enable static nat to vm1
4. Configure firewall rules e.g. enable icmp
5. Ping via public_ip, expect response from instance vm1

How did you try to break this feature and the system with this change?

[codecov]

Codecov Report

❌ Patch coverage is 6.45161% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.64%. Comparing base (75748a5) to head (ba07131).

Files with missing lines	Patch %	Lines
...a/com/cloud/network/router/CommandSetupHelper.java	0.00%	11 Missing ⚠️
...t/resource/virtualnetwork/model/StaticNatRule.java	0.00%	10 Missing ⚠️
...n/java/com/cloud/agent/api/to/StaticNatRuleTO.java	14.28%	6 Missing ⚠️
...ualnetwork/facade/SetStaticNatRulesConfigItem.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #13200      +/-   ##
============================================
- Coverage     19.65%   19.64%   -0.01%     
+ Complexity    19792    19790       -2     
============================================
  Files          6368     6368              
  Lines        575107   575137      +30     
  Branches      70370    70372       +2     
============================================
- Hits         113016   112998      -18     
- Misses       449808   449854      +46     
- Partials      12283    12285       +2     

Flag	Coverage Δ
uitests	3.41% <ø> (ø)
unittests	20.92% <6.45%> (-0.01%)	⬇️

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[sudo87]

@blueorangutan package

[blueorangutan]

@sudo87 a [SL] Jenkins job has been kicked to build packages. It will be bundled with no SystemVM templates. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 17959

[sudo87]

@blueorangutan package

[blueorangutan]

@sudo87 a [SL] Jenkins job has been kicked to build packages. It will be bundled with no SystemVM templates. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result [SF]: ✖️ el8 ✖️ el9 ✖️ debian ✖️ suse15. SL-JID 17986

[sudo87]

@blueorangutan package

[blueorangutan]

@sudo87 a [SL] Jenkins job has been kicked to build packages. It will be bundled with no SystemVM templates. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 17987

[github-actions]

This pull request has merge conflicts. Dear author, please fix the conflicts and sync your branch with the base branch.

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