multi: add confirmation target to loop in

loopd/swapclient_server.go

@@ -361,9 +361,16 @@ func (s *swapClientServer) GetLoopInQuote(ctx context.Context,
 
 	log.Infof("Loop in quote request received")
 
+	htlcConfTarget, err := validateLoopInRequest(
+		req.ConfTarget, req.ExternalHtlc,
+	)
+	if err != nil {
+		return nil, err
+	}
+
 	quote, err := s.impl.LoopInQuote(ctx, &loop.LoopInQuoteRequest{
 		Amount:         btcutil.Amount(req.Amt),
-		HtlcConfTarget: loop.DefaultHtlcConfTarget,
+		HtlcConfTarget: htlcConfTarget,
 		ExternalHtlc:   req.ExternalHtlc,
 	})
 	if err != nil {
@@ -381,11 +388,18 @@ func (s *swapClientServer) LoopIn(ctx context.Context,
 
 	log.Infof("Loop in request received")
 
+	htlcConfTarget, err := validateLoopInRequest(
+		in.HtlcConfTarget, in.ExternalHtlc,
+	)
+	if err != nil {
+		return nil, err
+	}
+
 	req := &loop.LoopInRequest{
 		Amount:         btcutil.Amount(in.Amt),
 		MaxMinerFee:    btcutil.Amount(in.MaxMinerFee),
 		MaxSwapFee:     btcutil.Amount(in.MaxSwapFee),
-		HtlcConfTarget: loop.DefaultHtlcConfTarget,
+		HtlcConfTarget: htlcConfTarget,
 		ExternalHtlc:   in.ExternalHtlc,
 	}
 	if in.LastHop != nil {
@@ -489,3 +503,22 @@ func validateConfTarget(target, defaultTarget int32) (int32, error) {
 		return target, nil
 	}
 }
+
+// validateLoopInRequest fails if the mutually exclusive conf target and
+// external parameters are both set.
+func validateLoopInRequest(htlcConfTarget int32, external bool) (int32, error) {
+	// If the htlc is going to be externally set, the htlcConfTarget should
+	// not be set, because it has no relevance when the htlc is external.
+	if external && htlcConfTarget != 0 {
+		return 0, errors.New("external and htlc conf target cannot " +
+			"both be set")
+	}
+
+	// If the htlc is being externally published, we do not need to set a
+	// confirmation target.
+	if external {
+		return 0, nil
+	}
+
+	return validateConfTarget(htlcConfTarget, loop.DefaultHtlcConfTarget)
+}

loopd/swapclient_server_test.go

@@ -1,6 +1,10 @@
 package loopd
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/lightninglabs/loop"
+)
 
 // TestValidateConfTarget tests all failure and success cases for our conf
 // target validation function, including the case where we replace a zero
@@ -70,3 +74,72 @@ func TestValidateConfTarget(t *testing.T) {
 		})
 	}
 }
+
+// TestValidateLoopInRequest tests validation of loop in requests.
+func TestValidateLoopInRequest(t *testing.T) {
+	tests := []struct {
+		name           string
+		external       bool
+		confTarget     int32
+		expectErr      bool
+		expectedTarget int32
+	}{
+		{
+			name:           "external and htlc conf set",
+			external:       true,
+			confTarget:     1,
+			expectErr:      true,
+			expectedTarget: 0,
+		},
+		{
+			name:           "external and no conf",
+			external:       true,
+			confTarget:     0,
+			expectErr:      false,
+			expectedTarget: 0,
+		},
+		{
+			name:           "not external, zero conf",
+			external:       false,
+			confTarget:     0,
+			expectErr:      false,
+			expectedTarget: loop.DefaultHtlcConfTarget,
+		},
+		{
+			name:           "not external, bad conf",
+			external:       false,
+			confTarget:     1,
+			expectErr:      true,
+			expectedTarget: 0,
+		},
+		{
+			name:           "not external, ok conf",
+			external:       false,
+			confTarget:     5,
+			expectErr:      false,
+			expectedTarget: 5,
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+
+		t.Run(test.name, func(t *testing.T) {
+			external := test.external
+			conf, err := validateLoopInRequest(
+				test.confTarget, external,
+			)
+
+			haveErr := err != nil
+			if haveErr != test.expectErr {
+				t.Fatalf("expected err: %v, got: %v",
+					test.expectErr, err)
+			}
+
+			if conf != test.expectedTarget {
+				t.Fatalf("expected: %v, got: %v",
+					test.expectedTarget, conf)
+			}
+		})
+	}
+}