__init__

2026-09-04 20:56:18 +00:00
commit 1022f24c34
43 changed files with 6160 additions and 0 deletions
@@ -0,0 +1,153 @@
+from __future__ import annotations
+
+import unittest
+from ipaddress import IPv4Address, IPv4Network
+
+from uvm.config import Settings
+from uvm.domain import VmRecord
+from uvm.errors import UvmError, ValidationError
+from uvm.network import NetworkManager
+from uvm.system import CommandResult
+
+
+class FakeRunner:
+    def __init__(self) -> None:
+        self.calls: list[tuple[str, ...]] = []
+        self.existing_links: set[str] = set()
+        self.link_details: dict[str, str] = {}
+
+    def run(self, command, *, check=True, capture=False, timeout=None) -> CommandResult:
+        del check, capture, timeout
+        args = tuple(str(part) for part in command)
+        self.calls.append(args)
+        if args[:3] == ("ip", "link", "show") and args[3] in self.existing_links:
+            return CommandResult(args=args, returncode=0)
+        if args[:6] == ("ip", "-j", "-d", "link", "show", "dev"):
+            return CommandResult(args=args, returncode=0, stdout=self.link_details[args[6]])
+        if args[:4] == ("ip", "link", "show", "uvm0"):
+            return CommandResult(args=args, returncode=1)
+        if args == ("ip", "route", "show", "default"):
+            return CommandResult(args=args, returncode=0, stdout="default via 192.0.2.1 dev eth0\n")
+        if len(args) > 3 and args[0] == "iptables" and "-C" in args:
+            return CommandResult(args=args, returncode=1)
+        return CommandResult(args=args, returncode=0)
+
+
+class NetworkManagerTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self.runner = FakeRunner()
+        self.network = NetworkManager(Settings(), runner=self.runner)  # type: ignore[arg-type]
+
+    def test_allocates_first_available_guest_address(self) -> None:
+        self.assertEqual(self.network.allocate_ip([], None), IPv4Address("10.42.0.2"))
+
+    def test_rejects_gateway_and_used_requested_addresses(self) -> None:
+        vm = VmRecord(
+            id="vm-test",
+            cpu=1,
+            ram_mib=512,
+            guest_ip="10.42.0.2",
+            gateway="10.42.0.1",
+            tap="uvm-test",
+            mac="02:fc:00:00:00:01",
+            socket="/tmp/firecracker.sock",
+            config="/tmp/config.json",
+            log="/tmp/firecracker.log",
+        )
+        with self.assertRaises(ValidationError):
+            self.network.allocate_ip([vm], IPv4Address("10.42.0.1"))
+        with self.assertRaises(ValidationError):
+            self.network.allocate_ip([vm], IPv4Address("10.42.0.2"))
+        with self.assertRaises(ValidationError):
+            self.network.allocate_ip([], IPv4Address("10.42.0.0"))
+        with self.assertRaises(ValidationError):
+            self.network.allocate_ip([], IPv4Address("10.42.0.255"))
+
+    def test_mac_and_tap_names_are_bounded_and_deterministic(self) -> None:
+        self.assertEqual(NetworkManager.mac_for(1), "02:fc:00:00:00:01")
+        tap = NetworkManager.tap_name("vm-0123456789abcdef")
+        self.assertLessEqual(len(tap), 15)
+        self.assertTrue(tap.startswith("uvm-"))
+
+    def test_bridge_setup_adds_a_missing_bridge_and_one_nat_rule(self) -> None:
+        self.network.ensure_bridge()
+
+        self.assertIn(("ip", "link", "add", "uvm0", "type", "bridge"), self.runner.calls)
+        self.assertIn(
+            ("ip", "addr", "replace", "10.42.0.1/24", "dev", "uvm0"),
+            self.runner.calls,
+        )
+        self.assertIn(
+            (
+                "iptables",
+                "-A",
+                "FORWARD",
+                "-i",
+                "uvm0",
+                "-o",
+                "eth0",
+                "-s",
+                "10.42.0.0/24",
+                "-j",
+                "ACCEPT",
+            ),
+            self.runner.calls,
+        )
+        checks = [
+            call
+            for call in self.runner.calls
+            if call[:5] == ("iptables", "-t", "nat", "-C", "POSTROUTING")
+        ]
+        self.assertEqual(len(checks), 1)
+        self.assertIn(
+            (
+                "iptables",
+                "-t",
+                "nat",
+                "-A",
+                "POSTROUTING",
+                "-s",
+                "10.42.0.0/24",
+                "-o",
+                "eth0",
+                "-j",
+                "MASQUERADE",
+            ),
+            self.runner.calls,
+        )
+
+    def test_bridge_and_guest_network_support_non_default_prefixes(self) -> None:
+        settings = Settings(
+            network=IPv4Network("10.50.0.0/16"),
+            gateway=IPv4Address("10.50.0.1"),
+        )
+        runner = FakeRunner()
+        NetworkManager(settings, runner=runner).ensure_bridge()  # type: ignore[arg-type]
+
+        self.assertIn(
+            ("ip", "addr", "replace", "10.50.0.1/16", "dev", "uvm0"),
+            runner.calls,
+        )
+
+    def test_refuses_to_adopt_an_existing_tap_device(self) -> None:
+        self.runner.existing_links.add("uvm-existing")
+
+        with self.assertRaises(UvmError):
+            self.network.create_tap("uvm-existing")
+
+        self.assertNotIn(
+            ("ip", "tuntap", "add", "dev", "uvm-existing", "mode", "tap"),
+            self.runner.calls,
+        )
+
+    def test_refuses_to_reconfigure_an_existing_non_bridge_interface(self) -> None:
+        self.runner.existing_links.add("uvm0")
+        self.runner.link_details["uvm0"] = '[{"linkinfo": {"info_kind": "dummy"}}]'
+
+        with self.assertRaises(UvmError):
+            self.network.ensure_bridge()
+
+        self.assertNotIn(
+            ("ip", "addr", "replace", "10.42.0.1/24", "dev", "uvm0"),
+            self.runner.calls,
+        )