multi: add zeroconfacceptor that default rejects if no rpc acceptors

This is a safety mechanism so that zero-conf channels are not accepted
by default if no rpc acceptor exists.

chanacceptor/zeroconfacceptor_test.go

@@ -0,0 +1,83 @@
+package chanacceptor
+
+import (
+	"testing"
+
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/stretchr/testify/require"
+)
+
+// dummyAcceptor is a ChannelAcceptor that will never return a failure.
+type dummyAcceptor struct{}
+
+func (d *dummyAcceptor) Accept(
+	req *ChannelAcceptRequest) *ChannelAcceptResponse {
+
+	return &ChannelAcceptResponse{}
+}
+
+// TestZeroConfAcceptorNormal verifies that the ZeroConfAcceptor will let
+// requests go through for non-zero-conf channels if there are no
+// sub-acceptors.
+func TestZeroConfAcceptorNormal(t *testing.T) {
+	t.Parallel()
+
+	// Create the zero-conf acceptor.
+	zeroAcceptor := NewZeroConfAcceptor()
+
+	// Assert that calling Accept won't return a failure.
+	req := &ChannelAcceptRequest{
+		OpenChanMsg: &lnwire.OpenChannel{},
+	}
+	resp := zeroAcceptor.Accept(req)
+	require.False(t, resp.RejectChannel())
+
+	// Add a dummyAcceptor to the zero-conf acceptor. Assert that Accept
+	// does not return a failure.
+	dummy := &dummyAcceptor{}
+	dummyID := zeroAcceptor.AddAcceptor(dummy)
+	resp = zeroAcceptor.Accept(req)
+	require.False(t, resp.RejectChannel())
+
+	// Remove the dummyAcceptor from the zero-conf acceptor and assert that
+	// Accept doesn't return a failure.
+	zeroAcceptor.RemoveAcceptor(dummyID)
+	resp = zeroAcceptor.Accept(req)
+	require.False(t, resp.RejectChannel())
+}
+
+// TestZeroConfAcceptorZC verifies that the ZeroConfAcceptor will fail
+// zero-conf channel opens unless a sub-acceptor exists.
+func TestZeroConfAcceptorZC(t *testing.T) {
+	t.Parallel()
+
+	// Create the zero-conf acceptor.
+	zeroAcceptor := NewZeroConfAcceptor()
+
+	channelType := new(lnwire.ChannelType)
+	*channelType = lnwire.ChannelType(*lnwire.NewRawFeatureVector(
+		lnwire.ZeroConfRequired,
+	))
+
+	// Assert that calling Accept results in failure.
+	req := &ChannelAcceptRequest{
+		OpenChanMsg: &lnwire.OpenChannel{
+			ChannelType: channelType,
+		},
+	}
+	resp := zeroAcceptor.Accept(req)
+	require.True(t, resp.RejectChannel())
+
+	// Add a dummyAcceptor to the zero-conf acceptor. Assert that Accept
+	// does not return a failure.
+	dummy := &dummyAcceptor{}
+	dummyID := zeroAcceptor.AddAcceptor(dummy)
+	resp = zeroAcceptor.Accept(req)
+	require.False(t, resp.RejectChannel())
+
+	// Remove the dummyAcceptor from the zero-conf acceptor and assert that
+	// Accept returns a failure.
+	zeroAcceptor.RemoveAcceptor(dummyID)
+	resp = zeroAcceptor.Accept(req)
+	require.True(t, resp.RejectChannel())
+}