fix: add IPv6 address check to service_manager for waypoint routing

[shivansh-gohem]

What type of PR is this?
/kind bug

What this PR does / why we need it:
This PR updates the service_manager function in the eBPF data plane to support IPv6 waypoint routing.

Previously, the service_manager logic only checked if service_v->wp_addr.ip4 != 0. This caused services with valid IPv6 waypoint addresses to be ignored and bypass the proxy.

This fix introduces a check for the ip6 array to ensure that if either an IPv4 or IPv6 address is present, the traffic is correctly routed to the waypoint manager.

Which issue this PR fixes:
Fixes #1460

Special notes for the reviewer:
The change is located in bpf/kmesh/workload/include/service.h.
I modified the conditional check to verify if any of the 4 segments of the IPv6 address are non-zero.

[kmesh-bot]

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[gemini-code-assist]

Summary of Changes

Hello @shivansh-gohem, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a critical bug in the eBPF data plane's service_manager that previously failed to recognize and route traffic for services using IPv6 waypoint addresses. By extending the conditional logic to explicitly check for the presence of an IPv6 address, the change guarantees that all waypoint-enabled services, regardless of their IP version, are correctly processed by the proxy, thereby maintaining intended traffic flow and security policies.

Highlights

• IPv6 Waypoint Routing Fix: The pull request addresses a bug where the service_manager in the eBPF data plane did not correctly handle IPv6 waypoint addresses, causing traffic to bypass the proxy.
• Enhanced Address Check: The service_manager function has been updated to include a check for IPv6 waypoint addresses, alongside the existing IPv4 check, ensuring proper routing for both.
• Impact on Service Routing: This change ensures that services configured with valid IPv6 waypoint addresses are now correctly recognized and routed through the waypoint manager, preventing unintended traffic bypasses.

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IPv6 unseen, Proxy bypass, now it's fixed, Traffic flows anew.

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[gemini-code-assist]

Code Review

This pull request correctly extends waypoint routing to support IPv6 by adding a check for IPv6 addresses in service_manager. The implementation is functional, but the condition can be simplified for better readability and efficiency. I've provided a suggestion to make the check more concise by using 64-bit comparisons and removing a redundant check.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.57%. Comparing base (3018401) to head (5418532).
⚠️ Report is 1 commits behind head on main.
see 1 file with indirect coverage changes

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[shivansh-gohem]

/cc @LiZhenCheng9527 @hzxuzhonghu