refactor: move utls roundtripper to pkg/net/utls

pkg/net/utls/utls.go

@@ -0,0 +1,62 @@
+package utls
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+	"time"
+
+	utls "github.com/refraction-networking/utls"
+	"golang.org/x/net/http2"
+)
+
+// UtlsRoundTripper uses uTLS + HTTP/2 to mimic Firefox and bypass Cloudflare JA3 detection
+type UtlsRoundTripper struct{}
+
+func (rt *UtlsRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	dialer := &net.Dialer{Timeout: 10 * time.Second}
+	host := req.URL.Hostname()
+	port := req.URL.Port()
+	if port == "" {
+		if req.URL.Scheme == "https" {
+			port = "443"
+		} else {
+			port = "80"
+		}
+	}
+	addr := net.JoinHostPort(host, port)
+
+	rawConn, err := dialer.DialContext(req.Context(), "tcp", addr)
+	if err != nil {
+		return nil, fmt.Errorf("tcp dial: %w", err)
+	}
+
+	uconn := utls.UClient(rawConn, &utls.Config{
+		ServerName: host,
+		NextProtos: []string{"h2", "http/1.1"},
+	}, utls.HelloFirefox_120)
+
+	if err := uconn.HandshakeContext(req.Context()); err != nil {
+		uconn.Close()
+		return nil, fmt.Errorf("utls handshake: %w", err)
+	}
+
+	alpn := uconn.ConnectionState().NegotiatedProtocol
+	if alpn == "h2" {
+		t := &http2.Transport{}
+		cc, err := t.NewClientConn(uconn)
+		if err != nil {
+			uconn.Close()
+			return nil, fmt.Errorf("http2 client conn: %w", err)
+		}
+		return cc.RoundTrip(req)
+	}
+
+	// Fallback to HTTP/1.1
+	if err := req.Write(uconn); err != nil {
+		uconn.Close()
+		return nil, fmt.Errorf("http1 write: %w", err)
+	}
+	return http.ReadResponse(bufio.NewReader(uconn), req)
+}