multi: move channel acceptor logic out of rpcserver

This commit moves and partially refactors the channel acceptor logic
added in c2a6c86e into the channel acceptor package. This allows us to
use the same logic in our unit tests as the rpcserver, rather than
needing to replicate it in unit tests.

Two changes are made to the existing implementation:
- Rather than having the Accept function run a closure, the closure
  originally used in the rpcserver is moved directly into Accept
- The done channel used to signal client exit is moved into the acceptor
  because the rpc server does not need knowledge of this detail (in
  addition to other fields required for mocking the actual rpc).

Crediting orginal committer as co-author:
Co-authored-by: Crypt-iQ

chanacceptor/acceptor_test.go

@@ -1,156 +1,207 @@
 package chanacceptor
 
 import (
-	"bytes"
-	"sync/atomic"
+	"errors"
+	"math/big"
 	"testing"
 	"time"
 
-	"github.com/lightningnetwork/lnd/lnrpc"
-
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/stretchr/testify/assert"
 )
 
-func randKey(t *testing.T) *btcec.PublicKey {
-	t.Helper()
+const testTimeout = time.Second
 
-	priv, err := btcec.NewPrivateKey(btcec.S256())
-	if err != nil {
-		t.Fatalf("unable to generate new public key")
-	}
+type channelAcceptorCtx struct {
+	t *testing.T
 
-	return priv.PubKey()
-}
+	// extRequests is the channel that we send our channel accept requests
+	// into, this channel mocks sending of a request to the rpc acceptor.
+	// This channel should be buffered with the number of requests we want
+	// to send so that it does not block (like a rpc stream).
+	extRequests chan []byte
 
-// requestInfo encapsulates the information sent from the RPCAcceptor to the
-// receiver on the other end of the stream.
-type requestInfo struct {
-	chanReq      *ChannelAcceptRequest
-	responseChan chan lnrpc.ChannelAcceptResponse
-}
+	// responses is a map of pending channel IDs to the response which we
+	// wish to mock the remote channel acceptor sending.
+	responses map[[32]byte]*lnrpc.ChannelAcceptResponse
 
-var defaultAcceptTimeout = 5 * time.Second
+	// acceptor is the channel acceptor we create for the test.
+	acceptor *RPCAcceptor
 
-func acceptAndIncrementCtr(rpc ChannelAcceptor, req *ChannelAcceptRequest,
-	ctr *uint32, success chan struct{}) {
+	// errChan is a channel that the error the channel acceptor exits with
+	// is sent into.
+	errChan chan error
+
+	// quit is a channel that can be used to shutdown the channel acceptor
+	// and return errShuttingDown.
+	quit chan struct{}
+}
 
-	result := rpc.Accept(req)
-	if !result {
-		return
+func newChanAcceptorCtx(t *testing.T, acceptCallCount int,
+	responses map[[32]byte]*lnrpc.ChannelAcceptResponse) *channelAcceptorCtx {
+
+	testCtx := &channelAcceptorCtx{
+		t:           t,
+		extRequests: make(chan []byte, acceptCallCount),
+		responses:   responses,
+		errChan:     make(chan error),
+		quit:        make(chan struct{}),
 	}
 
-	val := atomic.AddUint32(ctr, 1)
-	if val == 3 {
-		success <- struct{}{}
+	testCtx.acceptor = NewRPCAcceptor(
+		testCtx.receiveResponse, testCtx.sendRequest, testTimeout*5,
+		testCtx.quit,
+	)
+
+	return testCtx
+}
+
+// sendRequest mocks sending a request to the channel acceptor.
+func (c *channelAcceptorCtx) sendRequest(request *lnrpc.ChannelAcceptRequest) error {
+	select {
+	case c.extRequests <- request.PendingChanId:
+
+	case <-time.After(testTimeout):
+		c.t.Fatalf("timeout sending request: %v", request.PendingChanId)
 	}
+
+	return nil
 }
 
-// TestMultipleRPCClients tests that the RPCAcceptor is able to handle multiple
-// callers to its Accept method and respond to them correctly.
-func TestRPCMultipleAcceptClients(t *testing.T) {
+// receiveResponse mocks sending of a response from the channel acceptor.
+func (c *channelAcceptorCtx) receiveResponse() (*lnrpc.ChannelAcceptResponse,
+	error) {
 
-	var (
-		node = randKey(t)
+	select {
+	case id := <-c.extRequests:
+		scratch := [32]byte{}
+		copy(scratch[:], id)
 
-		firstOpenReq = &ChannelAcceptRequest{
-			Node: node,
-			OpenChanMsg: &lnwire.OpenChannel{
-				PendingChannelID: [32]byte{0},
-			},
-		}
+		resp, ok := c.responses[scratch]
+		assert.True(c.t, ok)
 
-		secondOpenReq = &ChannelAcceptRequest{
-			Node: node,
-			OpenChanMsg: &lnwire.OpenChannel{
-				PendingChannelID: [32]byte{1},
-			},
-		}
+		return resp, nil
 
-		thirdOpenReq = &ChannelAcceptRequest{
-			Node: node,
-			OpenChanMsg: &lnwire.OpenChannel{
-				PendingChannelID: [32]byte{2},
-			},
-		}
+	case <-time.After(testTimeout):
+		c.t.Fatalf("timeout receiving request")
+		return nil, errors.New("receiveResponse timeout")
 
-		counter uint32
-	)
+	// Exit if our test acceptor closes the done channel, which indicates
+	// that the acceptor is shutting down.
+	case <-c.acceptor.done:
+		return nil, errors.New("acceptor shutting down")
+	}
+}
 
-	quit := make(chan struct{})
-	defer close(quit)
+// start runs our channel acceptor in a goroutine which sends its exit error
+// into our test error channel.
+func (c *channelAcceptorCtx) start() {
+	go func() {
+		c.errChan <- c.acceptor.Run()
+	}()
+}
 
-	// Create channels to handle requests and successes.
-	requests := make(chan *requestInfo)
-	successChan := make(chan struct{})
-	errChan := make(chan struct{}, 4)
+// stop shuts down the test's channel acceptor and asserts that it exits with
+// our expected error.
+func (c *channelAcceptorCtx) stop() {
+	close(c.quit)
 
-	// demultiplexReq is a closure used to abstract the RPCAcceptor's request
-	// and response logic.
-	demultiplexReq := func(req *ChannelAcceptRequest) bool {
-		respChan := make(chan lnrpc.ChannelAcceptResponse, 1)
+	select {
+	case actual := <-c.errChan:
+		assert.Equal(c.t, errShuttingDown, actual)
 
-		newRequest := &requestInfo{
-			chanReq:      req,
-			responseChan: respChan,
-		}
+	case <-time.After(testTimeout):
+		c.t.Fatal("timeout waiting for acceptor to exit")
+	}
+}
 
-		// Send the newRequest to the requests channel.
-		select {
-		case requests <- newRequest:
-		case <-quit:
-			return false
+// queryAndAssert takes a map of open channel requests which we want to call
+// Accept for to the outcome we expect from the acceptor, dispatches each
+// request in a goroutine and then asserts that we get the outcome we expect.
+func (c *channelAcceptorCtx) queryAndAssert(queries map[*lnwire.OpenChannel]bool) {
+	var (
+		node = &btcec.PublicKey{
+			X: big.NewInt(1),
+			Y: big.NewInt(1),
 		}
 
-		// Receive the response and verify that the PendingChanId matches
-		// the ID found in the ChannelAcceptRequest. If no response has been
-		// received in defaultAcceptTimeout, then return false.
+		responses = make(chan struct{})
+	)
+
+	for request, expected := range queries {
+		request := request
+		expected := expected
+
+		go func() {
+			resp := c.acceptor.Accept(&ChannelAcceptRequest{
+				Node:        node,
+				OpenChanMsg: request,
+			})
+			assert.Equal(c.t, expected, resp)
+			responses <- struct{}{}
+		}()
+	}
+
+	// Wait for each of our requests to return a response before we exit.
+	for i := 0; i < len(queries); i++ {
 		select {
-		case resp := <-respChan:
-			pendingID := req.OpenChanMsg.PendingChannelID
-			if !bytes.Equal(pendingID[:], resp.PendingChanId) {
-				errChan <- struct{}{}
-				return false
-			}
-
-			return resp.Accept
-		case <-time.After(defaultAcceptTimeout):
-			errChan <- struct{}{}
-			return false
-		case <-quit:
-			return false
+		case <-responses:
+		case <-time.After(testTimeout):
+			c.t.Fatalf("did not receive response")
 		}
 	}
+}
 
-	rpcAcceptor := NewRPCAcceptor(demultiplexReq)
-
-	// Now we call the Accept method for each request.
-	go func() {
-		acceptAndIncrementCtr(rpcAcceptor, firstOpenReq, &counter, successChan)
-	}()
-
-	go func() {
-		acceptAndIncrementCtr(rpcAcceptor, secondOpenReq, &counter, successChan)
-	}()
+// TestMultipleAcceptClients tests that the RPC acceptor is capable of handling
+// multiple requests to its Accept function and responding to them correctly.
+func TestMultipleAcceptClients(t *testing.T) {
+	var (
+		chan1 = &lnwire.OpenChannel{
+			PendingChannelID: [32]byte{1},
+		}
+		chan2 = &lnwire.OpenChannel{
+			PendingChannelID: [32]byte{2},
+		}
+		chan3 = &lnwire.OpenChannel{
+			PendingChannelID: [32]byte{3},
+		}
 
-	go func() {
-		acceptAndIncrementCtr(rpcAcceptor, thirdOpenReq, &counter, successChan)
-	}()
+		// Queries is a map of the channel IDs we will query Accept
+		// with, and the set of outcomes we expect.
+		queries = map[*lnwire.OpenChannel]bool{
+			chan1: true,
+			chan2: false,
+			chan3: false,
+		}
 
-	for {
-		select {
-		case newRequest := <-requests:
-			newResponse := lnrpc.ChannelAcceptResponse{
+		// Responses is a mocked set of responses from the remote
+		// channel acceptor.
+		responses = map[[32]byte]*lnrpc.ChannelAcceptResponse{
+			chan1.PendingChannelID: {
+				PendingChanId: chan1.PendingChannelID[:],
 				Accept:        true,
-				PendingChanId: newRequest.chanReq.OpenChanMsg.PendingChannelID[:],
-			}
-
-			newRequest.responseChan <- newResponse
-		case <-errChan:
-			t.Fatalf("unable to accept ChannelAcceptRequest")
-		case <-successChan:
-			return
-		case <-quit:
+			},
+			chan2.PendingChannelID: {
+				PendingChanId: chan2.PendingChannelID[:],
+				Accept:        false,
+			},
+			chan3.PendingChannelID: {
+				PendingChanId: chan3.PendingChannelID[:],
+				Accept:        false,
+			},
 		}
-	}
+	)
+
+	// Create and start our channel acceptor.
+	testCtx := newChanAcceptorCtx(t, len(queries), responses)
+	testCtx.start()
+
+	// Dispatch three queries and assert that we get our expected response.
+	// for each.
+	testCtx.queryAndAssert(queries)
+
+	// Shutdown our acceptor.
+	testCtx.stop()
 }

chanacceptor/log.go

@@ -0,0 +1,32 @@
+package chanacceptor
+
+import (
+	"github.com/btcsuite/btclog"
+	"github.com/lightningnetwork/lnd/build"
+)
+
+// Subsystem defines the logging code for this subsystem.
+const Subsystem = "CHAC"
+
+// log is a logger that is initialized with no output filters.  This
+// means the package will not perform any logging by default until the caller
+// requests it.
+var log btclog.Logger
+
+// The default amount of logging is none.
+func init() {
+	UseLogger(build.NewSubLogger(Subsystem, nil))
+}
+
+// DisableLog disables all library log output.  Logging output is disabled
+// by default until UseLogger is called.
+func DisableLog() {
+	UseLogger(btclog.Disabled)
+}
+
+// UseLogger uses a specified Logger to output package logging info.
+// This should be used in preference to SetLogWriter if the caller is also
+// using btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}

chanacceptor/rpcacceptor.go

@@ -1,24 +1,255 @@
 package chanacceptor
 
+import (
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+)
+
+var errShuttingDown = errors.New("server shutting down")
+
+// chanAcceptInfo contains a request for a channel acceptor decision, and a
+// channel that the response should be sent on.
+type chanAcceptInfo struct {
+	request  *ChannelAcceptRequest
+	response chan bool
+}
+
 // RPCAcceptor represents the RPC-controlled variant of the ChannelAcceptor.
 // One RPCAcceptor allows one RPC client.
 type RPCAcceptor struct {
-	acceptClosure func(req *ChannelAcceptRequest) bool
+	// receive is a function from which we receive channel acceptance
+	// decisions. Note that this function is expected to block.
+	receive func() (*lnrpc.ChannelAcceptResponse, error)
+
+	// send is a function which sends requests for channel acceptance
+	// decisions into our rpc stream.
+	send func(request *lnrpc.ChannelAcceptRequest) error
+
+	// requests is a channel that we send requests for a acceptor response
+	// into.
+	requests chan *chanAcceptInfo
+
+	// timeout is the amount of time we allow the channel acceptance
+	// decision to take. This time includes the time to send a query to the
+	// acceptor, and the time it takes to receive a response.
+	timeout time.Duration
+
+	// done is closed when the rpc client terminates.
+	done chan struct{}
+
+	// quit is closed when lnd is shutting down.
+	quit chan struct{}
+
+	wg sync.WaitGroup
 }
 
 // Accept is a predicate on the ChannelAcceptRequest which is sent to the RPC
-// client who will respond with the ultimate decision. This assumes an accept
-// closure has been specified during creation.
+// client who will respond with the ultimate decision. This function passes the
+// request into the acceptor's requests channel, and returns the response it
+// receives, failing the request if the timeout elapses.
 //
 // NOTE: Part of the ChannelAcceptor interface.
 func (r *RPCAcceptor) Accept(req *ChannelAcceptRequest) bool {
-	return r.acceptClosure(req)
+	respChan := make(chan bool, 1)
+
+	newRequest := &chanAcceptInfo{
+		request:  req,
+		response: respChan,
+	}
+
+	// timeout is the time after which ChannelAcceptRequests expire.
+	timeout := time.After(r.timeout)
+
+	// Send the request to the newRequests channel.
+	select {
+	case r.requests <- newRequest:
+
+	case <-timeout:
+		log.Errorf("RPCAcceptor returned false - reached timeout of %v",
+			r.timeout)
+		return false
+
+	case <-r.done:
+		return false
+
+	case <-r.quit:
+		return false
+	}
+
+	// Receive the response and return it. If no response has been received
+	// in AcceptorTimeout, then return false.
+	select {
+	case resp := <-respChan:
+		return resp
+
+	case <-timeout:
+		log.Errorf("RPCAcceptor returned false - reached timeout of %v",
+			r.timeout)
+		return false
+
+	case <-r.done:
+		return false
+
+	case <-r.quit:
+		return false
+	}
 }
 
 // NewRPCAcceptor creates and returns an instance of the RPCAcceptor.
-func NewRPCAcceptor(closure func(*ChannelAcceptRequest) bool) *RPCAcceptor {
+func NewRPCAcceptor(receive func() (*lnrpc.ChannelAcceptResponse, error),
+	send func(*lnrpc.ChannelAcceptRequest) error,
+	timeout time.Duration, quit chan struct{}) *RPCAcceptor {
+
 	return &RPCAcceptor{
-		acceptClosure: closure,
+		receive:  receive,
+		send:     send,
+		requests: make(chan *chanAcceptInfo),
+		timeout:  timeout,
+		done:     make(chan struct{}),
+		quit:     quit,
+	}
+}
+
+// Run is the main loop for the RPC Acceptor. This function will block until
+// it receives the signal that lnd is shutting down, or the rpc stream is
+// cancelled by the client.
+func (r *RPCAcceptor) Run() error {
+	// Wait for our goroutines to exit before we return.
+	defer r.wg.Wait()
+
+	// Create a channel that responses from acceptors are sent into.
+	responses := make(chan lnrpc.ChannelAcceptResponse)
+
+	// errChan is used by the receive loop to signal any errors that occur
+	// during reading from the stream. This is primarily used to shutdown
+	// the send loop in the case of an RPC client disconnecting.
+	errChan := make(chan error, 1)
+
+	// Start a goroutine to receive responses from the channel acceptor.
+	// We expect the receive function to block, so it must be run in a
+	// goroutine (otherwise we could not send more than one channel accept
+	// request to the client).
+	r.wg.Add(1)
+	go func() {
+		r.receiveResponses(errChan, responses)
+		r.wg.Done()
+	}()
+
+	return r.sendAcceptRequests(errChan, responses)
+}
+
+// receiveResponses receives responses for our channel accept requests and
+// dispatches them into the responses channel provided, sending any errors that
+// occur into the error channel provided.
+func (r *RPCAcceptor) receiveResponses(errChan chan error,
+	responses chan lnrpc.ChannelAcceptResponse) {
+
+	for {
+		resp, err := r.receive()
+		if err != nil {
+			errChan <- err
+			return
+		}
+
+		var pendingID [32]byte
+		copy(pendingID[:], resp.PendingChanId)
+
+		openChanResp := lnrpc.ChannelAcceptResponse{
+			Accept:        resp.Accept,
+			PendingChanId: pendingID[:],
+		}
+
+		// We have received a decision for one of our channel
+		// acceptor requests.
+		select {
+		case responses <- openChanResp:
+
+		case <-r.done:
+			return
+
+		case <-r.quit:
+			return
+		}
+	}
+}
+
+// sendAcceptRequests handles channel acceptor requests sent to us by our
+// Accept() function, dispatching them to our acceptor stream and coordinating
+// return of responses to their callers.
+func (r *RPCAcceptor) sendAcceptRequests(errChan chan error,
+	responses chan lnrpc.ChannelAcceptResponse) error {
+
+	// Close the done channel to indicate that the acceptor is no longer
+	// listening and any in-progress requests should be terminated.
+	defer close(r.done)
+
+	acceptRequests := make(map[[32]byte]chan bool)
+
+	for {
+		select {
+		// Consume requests passed to us from our Accept() function and
+		// send them into our stream.
+		case newRequest := <-r.requests:
+
+			req := newRequest.request
+			pendingChanID := req.OpenChanMsg.PendingChannelID
+
+			acceptRequests[pendingChanID] = newRequest.response
+
+			// A ChannelAcceptRequest has been received, send it to the client.
+			chanAcceptReq := &lnrpc.ChannelAcceptRequest{
+				NodePubkey:       req.Node.SerializeCompressed(),
+				ChainHash:        req.OpenChanMsg.ChainHash[:],
+				PendingChanId:    req.OpenChanMsg.PendingChannelID[:],
+				FundingAmt:       uint64(req.OpenChanMsg.FundingAmount),
+				PushAmt:          uint64(req.OpenChanMsg.PushAmount),
+				DustLimit:        uint64(req.OpenChanMsg.DustLimit),
+				MaxValueInFlight: uint64(req.OpenChanMsg.MaxValueInFlight),
+				ChannelReserve:   uint64(req.OpenChanMsg.ChannelReserve),
+				MinHtlc:          uint64(req.OpenChanMsg.HtlcMinimum),
+				FeePerKw:         uint64(req.OpenChanMsg.FeePerKiloWeight),
+				CsvDelay:         uint32(req.OpenChanMsg.CsvDelay),
+				MaxAcceptedHtlcs: uint32(req.OpenChanMsg.MaxAcceptedHTLCs),
+				ChannelFlags:     uint32(req.OpenChanMsg.ChannelFlags),
+			}
+
+			if err := r.send(chanAcceptReq); err != nil {
+				return err
+			}
+
+		// Process newly received responses from our channel acceptor,
+		// looking the original request up in our map of requests and
+		// dispatching the response.
+		case resp := <-responses:
+			// Look up the appropriate channel to send on given the
+			// pending ID. If a channel is found, send the response
+			// over it.
+			var pendingID [32]byte
+			copy(pendingID[:], resp.PendingChanId)
+			respChan, ok := acceptRequests[pendingID]
+			if !ok {
+				continue
+			}
+
+			// Send the response boolean over the buffered response
+			// channel.
+			respChan <- resp.Accept
+
+			// Delete the channel from the acceptRequests map.
+			delete(acceptRequests, pendingID)
+
+		// If we failed to receive from our acceptor, we exit.
+		case err := <-errChan:
+			log.Errorf("Received an error: %v, shutting down", err)
+			return err
+
+		// Exit if we are shutting down.
+		case <-r.quit:
+			return errShuttingDown
+		}
 	}
 }
 

log.go

@@ -11,6 +11,7 @@ import (
 	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainreg"
+	"github.com/lightningnetwork/lnd/chanacceptor"
 	"github.com/lightningnetwork/lnd/chanbackup"
 	"github.com/lightningnetwork/lnd/chanfitness"
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -133,6 +134,7 @@ func SetupLoggers(root *build.RotatingLogWriter) {
 	AddSubLogger(root, verrpc.Subsystem, verrpc.UseLogger)
 	AddSubLogger(root, healthcheck.Subsystem, healthcheck.UseLogger)
 	AddSubLogger(root, chainreg.Subsystem, chainreg.UseLogger)
+	AddSubLogger(root, chanacceptor.Subsystem, chanacceptor.UseLogger)
 }
 
 // AddSubLogger is a helper method to conveniently create and register the

rpcserver.go

@@ -6399,14 +6399,6 @@ func (r *rpcServer) SubscribeChannelBackups(req *lnrpc.ChannelBackupSubscription
 	}
 }
 
-// chanAcceptInfo is used in the ChannelAcceptor bidirectional stream and
-// encapsulates the request information sent from the RPCAcceptor to the
-// RPCServer.
-type chanAcceptInfo struct {
-	chanReq      *chanacceptor.ChannelAcceptRequest
-	responseChan chan bool
-}
-
 // ChannelAcceptor dispatches a bi-directional streaming RPC in which
 // OpenChannel requests are sent to the client and the client responds with
 // a boolean that tells LND whether or not to accept the channel. This allows
@@ -6415,153 +6407,22 @@ type chanAcceptInfo struct {
 func (r *rpcServer) ChannelAcceptor(stream lnrpc.Lightning_ChannelAcceptorServer) error {
 	chainedAcceptor := r.chanPredicate
 
-	// Create two channels to handle requests and responses respectively.
-	newRequests := make(chan *chanAcceptInfo)
-	responses := make(chan lnrpc.ChannelAcceptResponse)
-
-	// Define a quit channel that will be used to signal to the RPCAcceptor's
-	// closure whether the stream still exists.
-	quit := make(chan struct{})
-	defer close(quit)
-
-	// demultiplexReq is a closure that will be passed to the RPCAcceptor and
-	// acts as an intermediary between the RPCAcceptor and the RPCServer.
-	demultiplexReq := func(req *chanacceptor.ChannelAcceptRequest) bool {
-		respChan := make(chan bool, 1)
-
-		newRequest := &chanAcceptInfo{
-			chanReq:      req,
-			responseChan: respChan,
-		}
-
-		// timeout is the time after which ChannelAcceptRequests expire.
-		timeout := time.After(r.cfg.AcceptorTimeout)
-
-		// Send the request to the newRequests channel.
-		select {
-		case newRequests <- newRequest:
-		case <-timeout:
-			rpcsLog.Errorf("RPCAcceptor returned false - reached timeout of %d",
-				r.cfg.AcceptorTimeout)
-			return false
-		case <-quit:
-			return false
-		case <-r.quit:
-			return false
-		}
-
-		// Receive the response and return it. If no response has been received
-		// in AcceptorTimeout, then return false.
-		select {
-		case resp := <-respChan:
-			return resp
-		case <-timeout:
-			rpcsLog.Errorf("RPCAcceptor returned false - reached timeout of %d",
-				r.cfg.AcceptorTimeout)
-			return false
-		case <-quit:
-			return false
-		case <-r.quit:
-			return false
-		}
-	}
-
-	// Create a new RPCAcceptor via the NewRPCAcceptor method.
-	rpcAcceptor := chanacceptor.NewRPCAcceptor(demultiplexReq)
+	// Create a new RPCAcceptor which will send requests into the
+	// newRequests channel when it receives them.
+	rpcAcceptor := chanacceptor.NewRPCAcceptor(
+		stream.Recv, stream.Send, r.cfg.AcceptorTimeout, r.quit,
+	)
 
 	// Add the RPCAcceptor to the ChainedAcceptor and defer its removal.
 	id := chainedAcceptor.AddAcceptor(rpcAcceptor)
 	defer chainedAcceptor.RemoveAcceptor(id)
 
-	// errChan is used by the receive loop to signal any errors that occur
-	// during reading from the stream. This is primarily used to shutdown the
-	// send loop in the case of an RPC client disconnecting.
-	errChan := make(chan error, 1)
-
-	// We need to have the stream.Recv() in a goroutine since the call is
-	// blocking and would prevent us from sending more ChannelAcceptRequests to
-	// the RPC client.
-	go func() {
-		for {
-			resp, err := stream.Recv()
-			if err != nil {
-				errChan <- err
-				return
-			}
-
-			var pendingID [32]byte
-			copy(pendingID[:], resp.PendingChanId)
-
-			openChanResp := lnrpc.ChannelAcceptResponse{
-				Accept:        resp.Accept,
-				PendingChanId: pendingID[:],
-			}
-
-			// Now that we have the response from the RPC client, send it to
-			// the responses chan.
-			select {
-			case responses <- openChanResp:
-			case <-quit:
-				return
-			case <-r.quit:
-				return
-			}
-		}
-	}()
-
-	acceptRequests := make(map[[32]byte]chan bool)
-
-	for {
-		select {
-		case newRequest := <-newRequests:
-
-			req := newRequest.chanReq
-			pendingChanID := req.OpenChanMsg.PendingChannelID
-
-			acceptRequests[pendingChanID] = newRequest.responseChan
-
-			// A ChannelAcceptRequest has been received, send it to the client.
-			chanAcceptReq := &lnrpc.ChannelAcceptRequest{
-				NodePubkey:       req.Node.SerializeCompressed(),
-				ChainHash:        req.OpenChanMsg.ChainHash[:],
-				PendingChanId:    req.OpenChanMsg.PendingChannelID[:],
-				FundingAmt:       uint64(req.OpenChanMsg.FundingAmount),
-				PushAmt:          uint64(req.OpenChanMsg.PushAmount),
-				DustLimit:        uint64(req.OpenChanMsg.DustLimit),
-				MaxValueInFlight: uint64(req.OpenChanMsg.MaxValueInFlight),
-				ChannelReserve:   uint64(req.OpenChanMsg.ChannelReserve),
-				MinHtlc:          uint64(req.OpenChanMsg.HtlcMinimum),
-				FeePerKw:         uint64(req.OpenChanMsg.FeePerKiloWeight),
-				CsvDelay:         uint32(req.OpenChanMsg.CsvDelay),
-				MaxAcceptedHtlcs: uint32(req.OpenChanMsg.MaxAcceptedHTLCs),
-				ChannelFlags:     uint32(req.OpenChanMsg.ChannelFlags),
-			}
-
-			if err := stream.Send(chanAcceptReq); err != nil {
-				return err
-			}
-		case resp := <-responses:
-			// Look up the appropriate channel to send on given the pending ID.
-			// If a channel is found, send the response over it.
-			var pendingID [32]byte
-			copy(pendingID[:], resp.PendingChanId)
-			respChan, ok := acceptRequests[pendingID]
-			if !ok {
-				continue
-			}
-
-			// Send the response boolean over the buffered response channel.
-			respChan <- resp.Accept
-
-			// Delete the channel from the acceptRequests map.
-			delete(acceptRequests, pendingID)
-		case err := <-errChan:
-			rpcsLog.Errorf("Received an error: %v, shutting down", err)
-			return err
-		case <-r.quit:
-			return fmt.Errorf("RPC server is shutting down")
-		}
-	}
+	// Run the rpc acceptor, which will accept requests for channel
+	// acceptance decisions from our chained acceptor, send them to the
+	// channel acceptor and listen for and report responses. This function
+	// blocks, and will exit if the rpcserver receives the instruction to
+	// shutdown, or the client cancels.
+	return rpcAcceptor.Run()
 }
 
 // BakeMacaroon allows the creation of a new macaroon with custom read and write