Add gun-lite gRPC implementation (#44)

transport/v2raygrpclite/client.go

@@ -0,0 +1,77 @@
+package v2raygrpclite
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/option"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+var _ adapter.V2RayClientTransport = (*Client)(nil)
+
+var defaultClientHeader = http.Header{
+	"Content-Type": []string{"application/grpc"},
+	"User-Agent":   []string{"grpc-go/1.48.0"},
+	"TE":           []string{"trailers"},
+}
+
+type Client struct {
+	ctx        context.Context
+	dialer     N.Dialer
+	serverAddr M.Socksaddr
+	transport  *http.Transport
+	options    option.V2RayGRPCOptions
+	url        *url.URL
+}
+
+func NewClient(ctx context.Context, dialer N.Dialer, serverAddr M.Socksaddr, options option.V2RayGRPCOptions, tlsConfig *tls.Config) adapter.V2RayClientTransport {
+	return &Client{
+		ctx:        ctx,
+		dialer:     dialer,
+		serverAddr: serverAddr,
+		options:    options,
+		transport: &http.Transport{
+			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+				return dialer.DialContext(ctx, network, M.ParseSocksaddr(addr))
+			},
+			ForceAttemptHTTP2: true,
+			TLSClientConfig:   tlsConfig,
+		},
+		url: &url.URL{
+			Scheme: "https",
+			Host:   serverAddr.String(),
+			Path:   fmt.Sprintf("/%s/Tun", url.QueryEscape(options.ServiceName)),
+		},
+	}
+}
+
+func (c *Client) DialContext(ctx context.Context) (net.Conn, error) {
+	pipeInReader, pipeInWriter := io.Pipe()
+	request := &http.Request{
+		Method:     http.MethodPost,
+		Body:       pipeInReader,
+		URL:        c.url,
+		Proto:      "HTTP/2",
+		ProtoMajor: 2,
+		Header:     defaultClientHeader,
+	}
+	request = request.WithContext(ctx)
+	conn := newLateGunConn(pipeInWriter)
+	go func() {
+		response, err := c.transport.RoundTrip(request)
+		if err == nil {
+			conn.setup(response.Body, nil)
+		} else {
+			conn.setup(nil, err)
+		}
+	}()
+	return conn, nil
+}