[PR #121] [CLOSED] fix(cps): implement <c> tag & tests - closes #120 #149

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opened 2026-10-13 21:04:03 +00:00 by bsakaguchi · 0 comments

bsakaguchi commented

2026-10-13 21:04:03 +00:00

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📋 Pull Request Information

Original PR: https://github.com/amnezia-vpn/amneziawg-go/pull/121
Author: @Vadim-Khristenko
Created: 3/2/2026
Status: ❌ Closed

Base: master ← Head: feature-implement-packet-counter-tag-for-cps

📝 Commits (1)

15cca22 feat(cps): implement packet counter tag for CPS

📊 Changes

6 files changed (+350 additions, -25 deletions)

View changed files

➕ device/csp_test.go (+264 -0)
📝 device/obf.go (+28 -14)
➕ device/obf_counter.go (+36 -0)
📝 device/peer.go (+9 -8)
📝 device/pools_test.go (+1 -1)
📝 device/send.go (+12 -2)

📄 Description

Summary

Implemented support for the <c> CPS tag: a 4‑byte big‑endian packet counter injected into custom signature packets. ( #120 )

What I changed

Implemented counter obfuscator: obf_counter.go
Parser: added newObfChainWithCounter and counter handling in obf.go
Sending path: increment & pass counter getter in send.go
Peer state: added cpsPacketCounter in peer.go
Tests: added global CPS tests in csp_test.go covering <b>, <r>, <rc>, <rd>, <t>, <c>, mixed chains and error cases
Fixed an existing test bug in pools_test.go (use max.Load() in error message)

Why this approach

<c> requires a runtime packet counter value, so the obfuscator needs a getter at construction time. To keep changes minimal and compatible with the existing obfBuilders map, I added a small special‑case path (newObfChainWithCounter) rather than changing the builders’ API. This keeps the rest of the code unchanged and localizes the counter logic.
Deobfuscate for the counter does not perform validation, consistent with other dynamic tags (random bytes/char/digits); if stronger validation is desired we can add it later.

Tests & verification

Added comprehensive CPS tests in csp_test.go. CPS tests pass locally.
Fixed pools_test.go so go vet / test runs no longer fail due to the previously incorrect usage.

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/amnezia-vpn/amneziawg-go/pull/121 **Author:** [@Vadim-Khristenko](https://github.com/Vadim-Khristenko) **Created:** 3/2/2026 **Status:** ❌ Closed **Base:** `master` ← **Head:** `feature-implement-packet-counter-tag-for-cps` --- ### 📝 Commits (1) - [`15cca22`](https://github.com/amnezia-vpn/amneziawg-go/commit/15cca2272a364dd4d8e01694adc45e567a923fe5) feat(cps): implement packet counter tag for CPS ### 📊 Changes **6 files changed** (+350 additions, -25 deletions) <details> <summary>View changed files</summary> ➕ `device/csp_test.go` (+264 -0) 📝 `device/obf.go` (+28 -14) ➕ `device/obf_counter.go` (+36 -0) 📝 `device/peer.go` (+9 -8) 📝 `device/pools_test.go` (+1 -1) 📝 `device/send.go` (+12 -2) </details> ### 📄 Description ## Summary - Implemented support for the `<c>` CPS tag: a 4‑byte big‑endian packet counter injected into custom signature packets. ( #120 ) ## What I changed - Implemented counter obfuscator: obf_counter.go - Parser: added `newObfChainWithCounter` and counter handling in obf.go - Sending path: increment & pass counter getter in send.go - Peer state: added `cpsPacketCounter` in peer.go - Tests: added global CPS tests in csp_test.go covering `<b>`, `<r>`, `<rc>`, `<rd>`, `<t>`, `<c>`, mixed chains and error cases - Fixed an existing test bug in pools_test.go (use `max.Load()` in error message) ## Why this approach - `<c>` requires a runtime packet counter value, so the obfuscator needs a getter at construction time. To keep changes minimal and compatible with the existing `obfBuilders` map, I added a small special‑case path (`newObfChainWithCounter`) rather than changing the builders’ API. This keeps the rest of the code unchanged and localizes the counter logic. - `Deobfuscate` for the counter does not perform validation, consistent with other dynamic tags (random bytes/char/digits); if stronger validation is desired we can add it later. ## Tests & verification - Added comprehensive CPS tests in csp_test.go. CPS tests pass locally. - Fixed pools_test.go so `go vet` / test runs no longer fail due to the previously incorrect usage. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

bsakaguchi

2026-10-13 21:04:03 +00:00