chore: refactor ServerTailnet to use tailnet.Controllers (#15408)

chore of #14729

Refactors the `ServerTailnet` to use `tailnet.Controller` so that we reuse logic around reconnection and handling control messages, instead of reimplementing.  This unifies our "client" use of the tailscale API across CLI, coderd, and wsproxy.

Author: spikecurtis

Makefile

@@ -507,7 +507,6 @@ gen: \
 	examples/examples.gen.json \
 	tailnet/tailnettest/coordinatormock.go \
 	tailnet/tailnettest/coordinateemock.go \
-	tailnet/tailnettest/multiagentmock.go \
 	coderd/database/pubsub/psmock/psmock.go
 .PHONY: gen
 
@@ -537,7 +536,6 @@ gen/mark-fresh:
 		examples/examples.gen.json \
 		tailnet/tailnettest/coordinatormock.go \
 		tailnet/tailnettest/coordinateemock.go \
-		tailnet/tailnettest/multiagentmock.go \
 		coderd/database/pubsub/psmock/psmock.go \
 		"
 
@@ -570,7 +568,7 @@ coderd/database/dbmock/dbmock.go: coderd/database/db.go coderd/database/querier.
 coderd/database/pubsub/psmock/psmock.go: coderd/database/pubsub/pubsub.go
 	go generate ./coderd/database/pubsub/psmock
 
-tailnet/tailnettest/coordinatormock.go tailnet/tailnettest/multiagentmock.go tailnet/tailnettest/coordinateemock.go: tailnet/coordinator.go tailnet/multiagent.go
+tailnet/tailnettest/coordinatormock.go tailnet/tailnettest/coordinateemock.go: tailnet/coordinator.go
 	go generate ./tailnet/tailnettest/
 
 tailnet/proto/tailnet.pb.go: tailnet/proto/tailnet.proto

agent/agent_test.go

@@ -1919,7 +1919,8 @@ func TestAgent_UpdatedDERP(t *testing.T) {
 		t.Cleanup(testCtxCancel)
 		clientID := uuid.New()
 		ctrl := tailnet.NewSingleDestController(logger, conn, agentID)
-		coordination := ctrl.New(tailnet.NewInMemoryCoordinatorClient(logger, clientID, agentID, coordinator))
+		auth := tailnet.ClientCoordinateeAuth{AgentID: agentID}
+		coordination := ctrl.New(tailnet.NewInMemoryCoordinatorClient(logger, clientID, auth, coordinator))
 		t.Cleanup(func() {
 			t.Logf("closing coordination %s", name)
 			cctx, ccancel := context.WithTimeout(testCtx, testutil.WaitShort)
@@ -2408,8 +2409,9 @@ func setupAgent(t *testing.T, metadata agentsdk.Manifest, ptyTimeout time.Durati
 	t.Cleanup(testCtxCancel)
 	clientID := uuid.New()
 	ctrl := tailnet.NewSingleDestController(logger, conn, metadata.AgentID)
+	auth := tailnet.ClientCoordinateeAuth{AgentID: metadata.AgentID}
 	coordination := ctrl.New(tailnet.NewInMemoryCoordinatorClient(
-		logger, clientID, metadata.AgentID, coordinator))
+		logger, clientID, auth, coordinator))
 	t.Cleanup(func() {
 		cctx, ccancel := context.WithTimeout(testCtx, testutil.WaitShort)
 		defer ccancel()

coderd/coderd.go

@@ -627,14 +627,17 @@ func New(options *Options) *API {
 
 	api.Auditor.Store(&options.Auditor)
 	api.TailnetCoordinator.Store(&options.TailnetCoordinator)
+	dialer := &InmemTailnetDialer{
+		CoordPtr: &api.TailnetCoordinator,
+		DERPFn:   api.DERPMap,
+		Logger:   options.Logger,
+		ClientID: uuid.New(),
+	}
 	stn, err := NewServerTailnet(api.ctx,
 		options.Logger,
 		options.DERPServer,
-		api.DERPMap,
+		dialer,
 		options.DeploymentValues.DERP.Config.ForceWebSockets.Value(),
-		func(context.Context) (tailnet.MultiAgentConn, error) {
-			return (*api.TailnetCoordinator.Load()).ServeMultiAgent(uuid.New()), nil
-		},
 		options.DeploymentValues.DERP.Config.BlockDirect.Value(),
 		api.TracerProvider,
 	)