Refactor iptables/ip6tables chain teardown into shared helper

[Copilot]

This PR addresses duplicated, security-sensitive chain teardown logic split across IPv4/IPv6 cleanup paths and setup pre-cleanup. The same list→match→delete (reverse order)→flush→delete sequence is now centralized to keep IPv4/IPv6 behavior in lockstep.

• Shared teardown primitive

  • Added cleanupChain in src/host-iptables-shared.ts to encapsulate:
    • optional DOCKER-USER reference removal
    • rule matching via default chain-name match or custom predicate
    • reverse-order deletion of DOCKER-USER rule numbers
    • final -F / -X chain teardown

• Cleanup path deduplication

  • Updated src/host-iptables-cleanup.ts to call cleanupChain for:
    • IPv4 (iptables, FW_WRAPPER) with bridge-aware match predicate (-i/-o <bridge> + chain)
    • IPv6 (ip6tables, FW_WRAPPER_V6) using default chain-name matching
  • Preserved conditional behavior when bridge name is unavailable.

• Setup path deduplication

  • Updated src/host-iptables-rules.ts pre-setup cleanup to reuse cleanupChain('iptables', CHAIN_NAME) when an existing chain is detected, removing the duplicated teardown block.

• Focused helper coverage

  • Added src/host-iptables-shared.test.ts with targeted coverage for:
    • reverse-order DOCKER-USER deletion
    • optional skip of DOCKER-USER reference removal

await cleanupChain('iptables', CHAIN_NAME, {
  removeDockerUserReferences: Boolean(bridgeName),
  matchPredicate: bridgeName
    ? (line) =>
        (line.includes(`-i ${bridgeName}`) || line.includes(`-o ${bridgeName}`)) &&
        line.includes(CHAIN_NAME)
    : undefined,
});

[Copilot]

Pull request overview

Centralizes the duplicated iptables/ip6tables chain teardown (DOCKER-USER reference removal + reverse-order delete + flush + drop chain) into a single cleanupChain helper, and refactors the IPv4 cleanup, IPv6 cleanup, and setup pre-cleanup paths to use it.

Changes:

• Add cleanupChain to host-iptables-shared.ts with optional DOCKER-USER reference removal and a customizable match predicate.
• Replace duplicated teardown code in host-iptables-cleanup.ts (IPv4 with bridge-aware predicate, IPv6 with default matching) and in host-iptables-rules.ts setup pre-cleanup.
• Add host-iptables-shared.test.ts covering reverse-order deletion and the skip-DOCKER-USER option.

Show a summary per file

File	Description
src/host-iptables-shared.ts	New shared cleanupChain helper
src/host-iptables-cleanup.ts	IPv4/IPv6 cleanup paths now delegate to cleanupChain
src/host-iptables-rules.ts	Setup pre-cleanup uses cleanupChain
src/host-iptables-shared.test.ts	Unit tests for the new helper

Copilot's findings

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• Files reviewed: 4/4 changed files
• Comments generated: 0

[github-actions]

Smoke Test Results

✅ GitHub API - Confirmed 2 PR entries in recent-prs.json
✅ Playwright - GitHub.com page title contains "GitHub"
✅ File verify - smoke-test-claude-26064180274.txt exists

Overall: PASS

💥 [THE END] — Illustrated by Smoke Claude

[github-actions]

🔥 Smoke Test: Copilot BYOK (Offline) Mode

Test	Result
GitHub MCP connectivity (list PRs)	✅
GitHub.com HTTP connectivity	⚠️ pre-step data unavailable (template not expanded)
File write/read	⚠️ pre-step data unavailable (template not expanded)
BYOK inference (agent → api-proxy → api.githubcopilot.com)	✅

Running in BYOK offline mode (COPILOT_OFFLINE=true) via api-proxy → api.githubcopilot.com.

PR by @Copilot, assignees: @lpcox @Copilot.

Overall: PARTIAL — BYOK inference and MCP connectivity confirmed ✅; pre-step smoke data was not expanded by the workflow runner.

🔑 BYOK report filed by Smoke Copilot BYOK

[github-actions]

🔬 Smoke Test Results

Test	Status
GitHub MCP connectivity	✅
GitHub.com HTTP connectivity	✅
File write/read	✅

PR: "Refactor iptables/ip6tables chain teardown into shared helper" by @Copilot
Assignees: @lpcox, @Copilot

Overall: PASS

📰 BREAKING: Report filed by Smoke Copilot

[github-actions]

Codex Smoke Test

✅ chore: recompile all workflow lock files
✅ refactor: split token-tracker.js into four focused modules
❌ safeinputs-gh unavailable; ❌ Tavily search unavailable; ⏭️ discussion skipped
✅ Playwright title; ✅ file/bash; ✅ npm build
Overall status: FAIL

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• registry.npmjs.org

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "registry.npmjs.org"

See Network Configuration for more information.

🔮 The oracle has spoken through Smoke Codex

[github-actions]

Smoke Test Results

• GitHub MCP Testing: ❌ (Tools missing)
• GitHub.com Connectivity: ❌ (Status 000)
• File Writing Testing: ✅
• Bash Tool Testing: ✅

Overall status: FAIL

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• localhost

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "localhost"

See Network Configuration for more information.

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[github-actions]

🏗️ Build Test Suite Results

Ecosystem	Project	Build/Install	Tests	Status
Bun	elysia	✅	1/1 passed	✅ PASS
Bun	hono	✅	1/1 passed	✅ PASS
C++	fmt	✅	N/A	✅ PASS
C++	json	✅	N/A	✅ PASS
Deno	oak	N/A	1/1 passed	✅ PASS
Deno	std	N/A	1/1 passed	✅ PASS
.NET	hello-world	✅	N/A	✅ PASS
.NET	json-parse	✅	N/A	✅ PASS
Go	color	✅	1/1 passed	✅ PASS
Go	env	✅	1/1 passed	✅ PASS
Go	uuid	✅	1/1 passed	✅ PASS
Java	gson	✅	1/1 passed	✅ PASS
Java	caffeine	✅	1/1 passed	✅ PASS
Node.js	clsx	✅	passed	✅ PASS
Node.js	execa	✅	passed	✅ PASS
Node.js	p-limit	✅	passed	✅ PASS
Rust	fd	✅	1/1 passed	✅ PASS
Rust	zoxide	✅	1/1 passed	✅ PASS

Overall: 8/8 ecosystems passed — ✅ PASS

Generated by Build Test Suite for issue #3359 · ● 8.1M · ◷

[github-actions]

Chroot Version Comparison Results

Runtime	Host Version	Chroot Version	Match?
Python	Python 3.12.13	Python 3.12.3	❌
Node.js	v24.15.0	v20.20.2	❌
Go	go1.22.12	go1.22.12	✅

Result: ❌ Not all versions match. Python and Node.js versions differ between host and chroot environments.

Tested by Smoke Chroot

[github-actions]

Smoke Test Results

• Redis PING: ❌ (connection timed out)
• PostgreSQL pg_isready: ❌ (no response)
• PostgreSQL SELECT 1: ❌ (skipped — host unreachable)

Overall: FAIL — host.docker.internal services are not reachable from this runner.

🔌 Service connectivity validated by Smoke Services

[lpcox]

@copilot address review feedback

[Copilot]

@copilot address review feedback

I checked all review threads/comments on this PR and there aren’t any actionable review findings to apply (the reviewer reported 0 comments). If you have specific feedback you want addressed, please share the comment link or details and I’ll apply it.