Initial inet_diag test suite

[rlmenge]

Add INET_DIAG_DESTROY Test Suite
Adds tests for CONFIG_INET_DIAG_DESTROY kernel feature - validates administrative TCP connection termination via ss -K.

INET_DIAG_DESTROY
"Provides a SOCK_DESTROY operation that allows privileged processes (e.g., a connection manager or a network administration tool such as ss) to close sockets opened by other processes. Closing a socket in this way interrupts any blocking read/write/connect operations on the socket and causes future socket calls to behave as if the socket had been disconnected. If unsure, say N."

Tests
verify_inet_diag_destroy (P2): Creates TCP connection, destroys with ss -K, verifies removal
verify_inet_diag_enabled (P3): Validates CONFIG_INET_DIAG and ss functionality

Validation
Tested on Fedora 43 and Ubuntu

[LiliDeng]

don't use warning level log

[LiliDeng]

move it into line 200

[LiliDeng]

remove unused code

[Copilot]

Pull request overview

This PR introduces a new test suite for validating the Linux kernel's INET_DIAG_DESTROY feature, which enables administrative termination of TCP connections via netlink socket interface. The implementation includes a new ss tool wrapper and comprehensive test cases to verify socket diagnostic capabilities.

Key Changes:

• New Ss tool class with methods for checking connection state, killing connections, and detecting kernel feature support
• Two test cases: verify_inet_diag_destroy (P2) validates connection termination functionality, and verify_inet_diag_enabled (P3) verifies basic INET_DIAG support
• Helper Python script that creates and maintains TCP connections for testing purposes

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
lisa/tools/ss.py	Implements the Ss tool wrapper with methods for connection management, kill support detection, and BSD compatibility
lisa/tools/__init__.py	Adds Ss import and exports it in the public API
lisa/microsoft/testsuites/network/inet_diag.py	Comprehensive test suite with helper methods for port discovery, connection state verification, and cleanup
lisa/microsoft/testsuites/network/TestScripts/lisa_tcp_test.py	Python script that creates persistent TCP server-client connections on specified ports for testing

---

[Copilot]

The cleanup in the finally block may fail silently if the process was never created or if pkill fails. The pkill command should be run with expected_exit_code_failure_message or at minimum log whether cleanup succeeded. Additionally, consider checking if connection_process is not None before attempting cleanup operations that depend on it having been created.

Suggested change

	if connection_process:
	node.execute(
	f"pkill -f {script_path}",
	sudo=True,
	)
	# Remove temporary script
	node.execute(f"rm -f {script_path}", sudo=True)
	if connection_process is not None:
	node.execute(
	f"pkill -f {script_path}",
	sudo=True,
	expected_exit_code=0,
	expected_exit_code_failure_message=(
	f"Failed to clean up TCP test process using pkill for script "
	f"{script_path}"
	),
	)
	# Remove temporary script
	node.execute(
	f"rm -f {script_path}",
	sudo=True,
	expected_exit_code=0,
	expected_exit_code_failure_message=(
	f"Failed to remove temporary script {script_path} during cleanup"
	),
	)