multi: add channel open parameters to channel acceptor

Add more fields to channel acceptor response so that users can have more
fine grained control over their incoming channels. With our chained
acceptor, it is possible that we get inconsistent responses from
multiple chained acceptors. We create a conjugate repsponse from all the
set fields in our various responses, but fail if we get different, non-
zero responses from our various acceptors. Separate merge functions are
used per type so that we avoid unexpected outcomes comparing interfaces
(panic on comparing types that aren't comparable), with casting used
where applicable to avoid code duplication.

chanacceptor/rpcacceptor_test.go

@@ -5,20 +5,33 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnwallet/chancloser"
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/stretchr/testify/require"
 )
 
 // TestValidateAcceptorResponse test validation of acceptor responses.
 func TestValidateAcceptorResponse(t *testing.T) {
-	customError := errors.New("custom error")
+	var (
+		customError = errors.New("custom error")
+		validAddr   = "bcrt1qwrmq9uca0t3dy9t9wtuq5tm4405r7tfzyqn9pp"
+		addr, _     = chancloser.ParseUpfrontShutdownAddress(
+			validAddr, &chaincfg.TestNet3Params,
+		)
+	)
 
 	tests := []struct {
 		name        string
+		dustLimit   btcutil.Amount
 		response    lnrpc.ChannelAcceptResponse
 		accept      bool
 		acceptorErr error
 		error       error
+		shutdown    lnwire.DeliveryAddress
 	}{
 		{
 			name: "accepted with error",
@@ -43,11 +56,13 @@ func TestValidateAcceptorResponse(t *testing.T) {
 		{
 			name: "accepted",
 			response: lnrpc.ChannelAcceptResponse{
-				Accept: true,
+				Accept:          true,
+				UpfrontShutdown: validAddr,
 			},
 			accept:      true,
 			acceptorErr: nil,
 			error:       nil,
+			shutdown:    addr,
 		},
 		{
 			name: "rejected with error",
@@ -68,18 +83,57 @@ func TestValidateAcceptorResponse(t *testing.T) {
 			acceptorErr: errChannelRejected,
 			error:       nil,
 		},
+		{
+			name: "invalid upfront shutdown",
+			response: lnrpc.ChannelAcceptResponse{
+				Accept:          true,
+				UpfrontShutdown: "invalid addr",
+			},
+			accept:      false,
+			acceptorErr: errChannelRejected,
+			error:       errInvalidUpfrontShutdown,
+		},
+		{
+			name:      "reserve too low",
+			dustLimit: 100,
+			response: lnrpc.ChannelAcceptResponse{
+				Accept:     true,
+				ReserveSat: 10,
+			},
+			accept:      false,
+			acceptorErr: errChannelRejected,
+			error:       errInsufficientReserve,
+		},
+		{
+			name:      "max htlcs too high",
+			dustLimit: 100,
+			response: lnrpc.ChannelAcceptResponse{
+				Accept:       true,
+				MaxHtlcCount: 1 + input.MaxHTLCNumber/2,
+			},
+			accept:      false,
+			acceptorErr: errChannelRejected,
+			error:       errMaxHtlcTooHigh,
+		},
 	}
 
 	for _, test := range tests {
 		test := test
 
 		t.Run(test.name, func(t *testing.T) {
-			accept, acceptErr, err := validateAcceptorResponse(
-				test.response,
+			// Create an acceptor, everything can be nil because
+			// we just need the params.
+			acceptor := NewRPCAcceptor(
+				nil, nil, 0, &chaincfg.TestNet3Params, nil,
+			)
+
+			accept, acceptErr, shutdown, err := acceptor.validateAcceptorResponse(
+				test.dustLimit, test.response,
 			)
 			require.Equal(t, test.accept, accept)
 			require.Equal(t, test.acceptorErr, acceptErr)
 			require.Equal(t, test.error, err)
+			require.Equal(t, test.shutdown, shutdown)
 		})
 	}
 }