feat(iosxr): Implement Route Policies

[sven-rosenzweig]

Compared with OpenConfig and Cisco NX-OS, IOS-XR-based route policies are more powerful and feature-rich. However, we currently do not need most of these advanced features. Instead, we adapt to the simpler route-map configuration model (sequence, condition, action, and disposition).

Route maps work by iterating over each entry in order of their sequence number. If a condition matches, the configured action is executed and processing stops after a match is found. The default action when no match is found is to pass.

We assume the same behavior with route policies: after each condition check, we set the policy result to "done" (which stops processing and accepts the route) or "drop" (which stops processing and rejects the route). At the end, if no match is found, the route is accepted by default.

Some key aspects that make Route Policies richer than route maps:

• Support for if/else control flow
• Referencing other RPLs within each other, creating nested blocks of policy logic
• Boolean operators (and, not, or)
• Parameterized route policy configuration
• Wildcard support in setting values

Yang support for Cisco IOS XR route policy support also differs from other OS models. It simply accepts one single policy string, being correctly formatted in the way mentioned above:

route-policy <name>
  if <sample statement> then
     set <sample set action>
     done
  endif
end-policy

https://github.com/YangModels/yang/blob/ad7aa9d483c592661c1df3d38bdfc99dc01cba56/vendor/cisco/xr/2522/Cisco-IOS-XR-um-route-policy-cfg.yang#L81-L94

[github-actions]

Merging this branch will increase overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/ironcore-dev/network-operator/internal/provider/cisco/iosxr	44.96% (+8.89%)	👍

---

Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/ironcore-dev/network-operator/internal/provider/cisco/iosxr/provider.go	21.96% (-0.74%)	214 (+7)	47	167 (+7)	👎
github.com/ironcore-dev/network-operator/internal/provider/cisco/iosxr/route_policies.go	73.87% (+73.87%)	111 (+108)	82 (+82)	29 (+26)	🌟

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

Changed unit test files

• github.com/ironcore-dev/network-operator/internal/provider/cisco/iosxr/route_policies_test.go