envoyproxy/envoy

Need CEL convenience function: inIpRange()

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#32,170 opened on Feb 2, 2024

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area/celenhancementhelp wanted

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Description

Currently, Envoy's CEL functions are essentially what the mainline CEL repo provides. However, as more use cases pile up, it may be worthwhile to add some additional convenience functions (where sensible) to make configuration & processing faster in Envoy.

In the case of this issue, the function being requested is inIpRange(). We have attributes that contain IP data (source.address, destination.address, etc.). Often times, a user wants to check if the IP is in a range. Its clunky and error prone to do this with string matches. So the request is to add an inIpRange() CEL function to Envoy whose semantics are like inIpRange(source.address, '9.9.9.0/24')

cc @kyessenov @tyxia

Contributor guide

Research direction
Examine existing CEL functions in Envoy's source code (e.g., under `source/extensions/filters/common/expr/`), understand how they are registered and implemented, then study Envoy's attribute system to access source/destination addresses. Implement `inIpRange` using a CIDR library (e.g., `absl::Int128` or a custom parser), add tests, and document the new function.
Tech stack
cpp
Domain
backendnetworking
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++networking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50