feature: Adding apipa nic support for swiftv2 windows

[tamilmani1989]

This PR updates both CNS and CNI code to support apipa nic creation in swiftv2. The code has been refactored to construct apipa nic as separate entry in podIpInfo if either of allowhostonc or allownctohost set. CNI when it does RequestIPs call to CNS and CNS return apipa nic as separate entry in PodIPInfo. This allows CNI to treat this as separate endpoint and align with current cni design/model of 1 nic per endpoint info. CNI then iterates through endpoint info and creates one nic at a time. NetworkContainerID is included in PodIPInfo as apipa endpoint creation gets details based on that. This is also required during delete as HNS endpoint for apipa is constructed based on networkcontainerid. Added DeleteEndpointState API in CNS to remove state when CNI delete call is invoked. DeleteEndpointState removes state from CNS statefile.

CNS State looks like this:

{
        "Endpoints": {
                "230ebd0bcea0220dd0bcb82fbc1a84c7d91f8cad53ff503e3e6b816d55aa35d9": {
                        "PodName": "",
                        "PodNamespace": "",
                        "IfnameToIPMap": {
                                "Ethernet 3": {
                                        "IPv4": null,
                                        "HnsEndpointID": "8d07a074-796c-4cbf-921e-14bf29d78cae",
                                        "HnsNetworkID": "89e5843c-68b6-4f6c-a3c7-c602380d8909",
                                        "MacAddress": "00:22:48:0a:7a:c3",
                                        "NICType": "FrontendNIC"
                                },
                                "HostNCApipaEndpoint-Swift_1fe8a29c-c61c-480c-8732-ff369f97a5cd": {
                                        "IPv4": null,
                                        "HnsEndpointID": "92e64863-c91a-4123-b417-0a8bf6ed7c80",
                                        "NetworkContainerID": "Swift_1fe8a29c-c61c-480c-8732-ff369f97a5cd",
                                        "NICType": "ApipaNIC"
                                }
                        }
                },

Reason for Change:

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• relevant PR labels added

Notes:

[Copilot]

Pull Request Overview

This PR refactors the handling of APIPA (Automatic Private IP Addressing) NICs by creating them as separate entries in the podIpInfo structure when either allowhostonc or allownctohost flags are set. This aligns with the CNI design model of having one NIC per endpoint.

• Introduces a new ApipaNIC type constant for APIPA network interface classification
• Adds logic to create separate APIPA NIC entries in CNS when communication flags are enabled
• Updates CNI to handle APIPA NICs with specialized configuration including skipped default routes

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
cns/NetworkContainerContract.go	Adds ApipaNIC constant and communication flags to PodIpInfo struct
cns/restserver/ipam.go	Implements logic to create separate APIPA NIC entries when communication flags are set
cni/network/invoker_cns.go	Adds APIPA NIC handling in CNI with specialized configuration function
network/network_windows.go	Updates network creation logic to skip network creation for APIPA NICs

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[github-actions]

This pull request is stale because it has been open for 2 weeks with no activity. Remove stale label or comment or this will be closed in 7 days

[github-actions]

Pull request closed due to inactivity.

[tamilmani1989]

reopen