Add MANUAL proxy-arp mode and manual-ip-range to openconfig-if-ip IPv4 mode

[jsingh2-c]

…penconfig-if-ip model

Change Scope

• [This change extends the openconfig-if-ip model to support selective (manual) IPv4 proxy ARP behavior using both CIDR prefixes and explicit IP address ranges. Introduces a new typedef ipv4-address-range to represent IPv4 address ranges (e.g. 10.0.0.1-10.0.0.5). Added a new container manual-ip-ranges under /ipv4/proxy-arp & models each entry using an OpenConfig list with condif/state separation. This allows each entry to be defined as either an IPv4 prefix (oc-inet:ipv4-prefix) or an address range (ipv4-address-range) via a union type. The changes also extends /proxy-arp/config/mode with a new value MANUAL, which is a mode in which proxy ARP responses are generated only when the target IPv4 address matches a configured prefix or range in manual-ip-ranges or matches an IP address assigned to the receiving interface]
• [This change is fully backward compatible:
  Existing enum values (DISABLE, REMOTE_ONLY, ALL) remain unchanged.
  Existing clients not using MANUAL mode are unaffected.
  The new list is optional and has no operational effect unless mode=MANUAL.]

Platform Implementations

• Implementation A: Ciena 6500
  The platform requires operator‑controlled manual proxy ARP for deployment scenarios.
  The implementation uses Linux kernel proxy ARP + NFtables filtering.
  [link to documentation](Vendor documentation for this feature is currently internal and not publicly
  shareable prior to feature completion. The externally visible behavior is fully described by the YANG model semantics.)
• Implementation B: OpenROADM Proxy ARP Model
  OpenROADM models a similar structure for proxy ARP entries as “proxy‑subnet” using CIDR prefixes, which our model aligns with conceptually. link to documentation

Tree View

[Next, cut and paste the relevant portion of the tree with enough context for reviewers to quickly understand the change.]

 module: openconfig-if-ip
    augment /oc-if:interfaces/oc-if:interface/oc-if:subinterfaces/oc-if:subinterface:
     +--rw ipv4
        +--rw addresses
        |  +--rw address* [ip]
        |     +--rw ip        -> ../config/ip
        |     +--rw config
        |     |  +--rw ip?              oc-inet:ipv4-address
        |     |  +--rw prefix-length?   uint8
        |     |  +--rw type?            ipv4-address-type
        |     +--ro state
        |     |  +--ro ip?              oc-inet:ipv4-address
        |     |  +--ro prefix-length?   uint8
        |     |  +--ro type?            ipv4-address-type
        |     |  +--ro origin?          ip-address-origin
        |     +--rw vrrp
        |        +--rw vrrp-group* [virtual-router-id]
        |           +--rw virtual-router-id     -> ../config/virtual-router-id
        |           +--rw config
        |           |  +--rw virtual-router-id?        uint8
        |           |  +--rw virtual-address*          oc-inet:ip-address
        |           |  +--rw priority?                 uint8
        |           |  +--rw preempt?                  boolean
        |           |  +--rw preempt-delay?            uint16
        |           |  +--rw accept-mode?              boolean
        |           |  +--rw advertisement-interval?   uint16
        |           +--ro state
        |           |  +--ro virtual-router-id?        uint8
        |           |  +--ro virtual-address*          oc-inet:ip-address
        |           |  +--ro priority?                 uint8
        |           |  +--ro preempt?                  boolean
        |           |  +--ro preempt-delay?            uint16
        |           |  +--ro accept-mode?              boolean
        |           |  +--ro advertisement-interval?   uint16
        |           |  +--ro current-priority?         uint8
        |           +--rw interface-tracking
        |              +--rw config
        |              |  +--rw track-interface*      -> /oc-if:interfaces/interface/name
        |              |  +--rw priority-decrement?   uint8
        |              +--ro state
        |                 +--ro track-interface*      -> /oc-if:interfaces/interface/name
        |                 +--ro priority-decrement?   uint8
        +--rw proxy-arp
        |  +--rw config
        |  |  +--rw mode?   enumeration
        |  +--ro state
-       |     +--ro mode?   enumeration
+       |  |  +--ro mode?   enumeration
+       |  +--rw manual-ip-ranges
+       |     +--rw manual-ip-range* [ip-range]
+       |        +--rw ip-range    -> ../config/ip-range
+       |        +--rw config
+       |        |  +--rw ip-range?   union
+       |        +--ro state
+       |           +--ro ip-range?   union
        +--rw neighbors
        |  +--rw neighbor* [ip]
        |     +--rw ip        -> ../config/ip
        |     +--rw config
        |     |  +--rw ip?                   oc-inet:ipv4-address
        |     |  +--rw link-layer-address    oc-yang:phys-address
        |     +--ro state
        |        +--ro ip?                   oc-inet:ipv4-address
        |        +--ro link-layer-address    oc-yang:phys-address
        |        +--ro origin?               neighbor-origin

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[gemini-code-assist]

Code Review

This pull request updates the OpenConfig IPv4 proxy ARP model to version 3.10.0, introducing a 'MANUAL' mode and a corresponding 'manual-ip-prefixes' list for explicit prefix configuration. The review feedback suggests improving the clarity of the documentation by explicitly referring to 'proxy ARP mode' in the descriptions of the new configuration elements to ensure consistency and avoid ambiguity.

[dplore]

Please add more description in the yang model of what the MANUAL mode is. Is this a filter of which client IP address the device will respond to ARP requests when doing proxy-ARP?

The Ciena link only goes to the main website. Please add a link to documentation describing the feature being added.

[jsingh2-c]

Please add more description in the yang model of what the MANUAL mode is. Is this a filter of which client IP address the device will respond to ARP requests when doing proxy-ARP?

The Ciena link only goes to the main website. Please add a link to documentation describing the feature being added.

Updated the Change Scope section to clearly explain the rationale for modeling manual (prefix-based) proxy ARP behavior and clarified MANUAL mode semantics.
Updated the Platform Implementations section to explain the reference implementation and note that vendor documentation is currently internal, with model behavior fully defined by the YANG descriptions.

[jsingh2-c]

Rebased the branch onto the latest upstream master.
Updated the YANG descriptions to clarify MANUAL proxy ARP semantics (including explicit target IPv4 address matching) and updated the PR description to better describe the rationale and reference implementation context. Thanks for the review.

[ElodinLaarz]

/gcbrun

[OpenConfigBot]

No major YANG version changes in commit 5d99115

[ElodinLaarz]

Reviewed at the OC Operators Meeting on May 5th, 2026:

Seems reasonable.

Failing whitespace CI check can be fixed. Will move to last-call if there are no objections in 2 weeks.

[ElodinLaarz]

Reviewed in OC Operators Meet May 19th, 2026:

Forgot to move to last-call, but the checks need to be fixed as well.

Adding to last-call for next week.

[jsingh2-c]

Thanks for the review and feedback so far.
To further improve usability and better align with real deployment needs, we are internally evaluating some enhancements around the modeling, specifically to support a broader range of use cases, including handling both individual prefixes and wider IP ranges more flexibly.
We’ll consolidate these changes and update the PR accordingly over the next couple of days.

[dplore]

Given this PR is planned to be revised by the author, I am moving to the the "waiting for author" queue. Please ping us when ready for review.

[jsingh2-c]

@dplore The PR has been updated and is ready for review. Changes since last version:

1. Renamed manual-ip-prefixes → manual-ip-ranges with a union type (ipv4-prefix | ipv4-address-range) to support both CIDR prefixes and explicit IP ranges
2. Fixed CI failures (added required oc-ext:posix-pattern)