Initial Commit

tests/vm_probe.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+"""Connectivity probe, run as the sandbox uid by tests/vm_host_asserts.sh.
+
+Prints one `target VERDICT` line per argument. Deliberately dumb: it makes
+a TCP connection and reports whether it completed. A blocked address looks
+the same as an unreachable one from in here, which is why the caller pairs
+every must-fail target with a must-pass positive control - without those,
+a suite like this passes just as happily when networking is simply broken.
+"""
+import socket
+import sys
+
+
+def probe(host: str, port: int, timeout: float = 4.0) -> str:
+    try:
+        socket.create_connection((host, port), timeout).close()
+        return "REACHED"
+    except Exception as exc:
+        return f"blocked({type(exc).__name__})"
+
+
+for spec in sys.argv[1:]:
+    host, _, port = spec.rpartition(":")
+    print(f"{spec} {probe(host, int(port))}", flush=True)