fixed v4 gateway resolution

api/gateway/tron/internal/service/gateway/tronclient/client.go

@@ -6,6 +6,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"math/big"
+	"net"
 	"net/url"
 	"strings"
 	"time"
@@ -27,7 +28,7 @@ type Client struct {
 }
 
 // NewClient creates a new TRON gRPC client connected to the given endpoint.
-func NewClient(grpcURL string, timeout time.Duration, authToken string) (*Client, error) {
+func NewClient(grpcURL string, timeout time.Duration, authToken string, forceIPv4 bool) (*Client, error) {
 	if grpcURL == "" {
 		return nil, merrors.InvalidArgument("tronclient: grpc url is required")
 	}
@@ -50,6 +51,9 @@ func NewClient(grpcURL string, timeout time.Duration, authToken string) (*Client
 	}
 
 	opts := []grpc.DialOption{transportCreds}
+	if forceIPv4 {
+		opts = append(opts, grpc.WithContextDialer(grpcForceIPv4Dialer))
+	}
 	if token := strings.TrimSpace(authToken); token != "" {
 		opts = append(opts,
 			grpc.WithUnaryInterceptor(grpcTokenUnaryInterceptor(token)),
@@ -67,6 +71,40 @@ func NewClient(grpcURL string, timeout time.Duration, authToken string) (*Client
 	}, nil
 }
 
+func grpcForceIPv4Dialer(ctx context.Context, address string) (net.Conn, error) {
+	host, port, err := net.SplitHostPort(address)
+	if err != nil {
+		return nil, err
+	}
+
+	// Resolve IPv4 only
+	ips, err := net.DefaultResolver.LookupIP(ctx, "ip4", host)
+	if err != nil {
+		return nil, err
+	}
+	if len(ips) == 0 {
+		return nil, merrors.Internal(fmt.Sprintf("no IPv4 address found for %s", host))
+	}
+
+	var dialer net.Dialer
+	var lastErr error
+	for _, ip := range ips {
+		target := net.JoinHostPort(ip.String(), port)
+		conn, err := dialer.DialContext(ctx, "tcp4", target)
+		if err == nil {
+			return conn, nil
+		}
+		lastErr = err
+		if ctx.Err() != nil {
+			break
+		}
+	}
+	if lastErr != nil {
+		return nil, merrors.Internal(fmt.Sprintf("failed to dial any IPv4 address for %s: %v", host, lastErr))
+	}
+	return nil, merrors.Internal(fmt.Sprintf("failed to dial IPv4 address for %s", host))
+}
+
 func normalizeGRPCAddress(grpcURL string) (string, bool, error) {
 	target := strings.TrimSpace(grpcURL)
 	useTLS := false