Implement OSPF control plane and dynamic routing

apps/api/src/regression/ospf.test.ts

@@ -0,0 +1,126 @@
+import { describe, expect, it } from "vitest";
+
+import { World } from "../sim/world.js";
+
+function configureInterface(
+  world: World,
+  deviceId: string,
+  interfaceName: string,
+  address: string,
+  mask = "255.255.255.252",
+  cost = 10
+): void {
+  const device = world.getDevice(deviceId);
+  if (!device) throw new Error(`missing device ${deviceId}`);
+  device.config.interfaces[interfaceName] = {
+    name: interfaceName,
+    adminUp: true,
+    ipv4Address: address,
+    ipv4Mask: mask,
+    ospfCost: cost
+  };
+}
+
+function enableOspf(world: World, deviceId: string, routerId: string, area = 0): void {
+  world.configureOspf(deviceId, {
+    enabled: true,
+    processId: 1,
+    routerId,
+    networks: [{ network: "10.0.0.0", wildcard: "0.255.255.255", area }]
+  });
+}
+
+function buildThreeRouterLine(): World {
+  const world = new World();
+  world.createDevice({ id: "R1", type: "router", hostname: "R1" });
+  world.createDevice({ id: "R2", type: "router", hostname: "R2" });
+  world.createDevice({ id: "R3", type: "router", hostname: "R3" });
+
+  configureInterface(world, "R1", "GigabitEthernet0/0", "10.12.0.1");
+  configureInterface(world, "R2", "GigabitEthernet0/0", "10.12.0.2");
+  configureInterface(world, "R2", "GigabitEthernet0/1", "10.23.0.2");
+  configureInterface(world, "R3", "GigabitEthernet0/0", "10.23.0.3");
+
+  world.createLink({
+    id: "R1-R2",
+    a: { deviceId: "R1", interfaceName: "GigabitEthernet0/0" },
+    b: { deviceId: "R2", interfaceName: "GigabitEthernet0/0" },
+    cableType: "copper_crossover"
+  });
+  world.createLink({
+    id: "R2-R3",
+    a: { deviceId: "R2", interfaceName: "GigabitEthernet0/1" },
+    b: { deviceId: "R3", interfaceName: "GigabitEthernet0/0" },
+    cableType: "copper_crossover"
+  });
+
+  enableOspf(world, "R1", "1.1.1.1");
+  enableOspf(world, "R2", "2.2.2.2");
+  enableOspf(world, "R3", "3.3.3.3");
+  return world;
+}
+
+describe("OSPF control plane", () => {
+  it("forms full adjacencies and produces a shared link-state database", () => {
+    const world = buildThreeRouterLine();
+    const r2 = world.getOspfSnapshot("R2");
+
+    expect(r2).not.toBeNull();
+    expect(r2?.neighbors).toEqual([
+      expect.objectContaining({ neighborDeviceId: "R1", state: "full", area: 0 }),
+      expect.objectContaining({ neighborDeviceId: "R3", state: "full", area: 0 })
+    ]);
+    expect(r2?.lsdb.map((lsa) => lsa.advertisingRouter)).toEqual([
+      "1.1.1.1",
+      "2.2.2.2",
+      "3.3.3.3"
+    ]);
+  });
+
+  it("runs SPF and installs a remote route with deterministic next hop and metric", () => {
+    const world = buildThreeRouterLine();
+    const r1 = world.getOspfSnapshot("R1");
+    const route = r1?.routes.find(
+      (candidate) => candidate.destination === "10.23.0.0" && candidate.mask === "255.255.255.252"
+    );
+
+    expect(route).toEqual(
+      expect.objectContaining({
+        nextHop: "10.12.0.2",
+        outgoingInterface: "GigabitEthernet0/0",
+        metric: 20,
+        learnedFrom: "2.2.2.2"
+      })
+    );
+  });
+
+  it("uses learned OSPF routes for bidirectional forwarding", () => {
+    const world = buildThreeRouterLine();
+
+    expect(world.canPing("R1", "10.23.0.3")).toBe(true);
+    expect(world.traceRoute("R1", "10.23.0.3")).toEqual({
+      ok: true,
+      hops: ["10.12.0.2", "10.23.0.3"]
+    });
+  });
+
+  it("withdraws routes immediately after a link failure", () => {
+    const world = buildThreeRouterLine();
+    expect(world.getOspfSnapshot("R1")?.routes).toHaveLength(1);
+
+    world.deleteLink("R2-R3");
+
+    expect(world.getOspfSnapshot("R1")?.routes).toEqual([]);
+    expect(world.canPing("R1", "10.23.0.3")).toBe(false);
+  });
+
+  it("does not form an adjacency across an area mismatch", () => {
+    const world = buildThreeRouterLine();
+    enableOspf(world, "R3", "3.3.3.3", 1);
+
+    expect(world.getOspfSnapshot("R2")?.neighbors.map((neighbor) => neighbor.neighborDeviceId)).toEqual([
+      "R1"
+    ]);
+    expect(world.canPing("R1", "10.23.0.3")).toBe(false);
+  });
+});