add udp relay support for http handler

pkg/handler/http/handler.go

@@ -90,6 +90,11 @@ func (h *httpHandler) handleRequest(ctx context.Context, conn net.Conn, req *htt
 		req.URL.Scheme = "http"
 	}
 
+	network := req.Header.Get("X-Gost-Protocol")
+	if network != "udp" {
+		network = "tcp"
+	}
+
 	// Try to get the actual host.
 	// Compatible with GOST 2.x.
 	if v := req.Header.Get("Gost-Target"); v != "" {
@@ -168,6 +173,11 @@ func (h *httpHandler) handleRequest(ctx context.Context, conn net.Conn, req *htt
 		return
 	}
 
+	if network == "udp" {
+		h.handleUDP(ctx, conn, network, req.Host)
+		return
+	}
+
 	if req.Method == "PRI" ||
 		(req.Method != http.MethodConnect && req.URL.Scheme != "http") {
 		resp.StatusCode = http.StatusBadRequest
@@ -187,7 +197,7 @@ func (h *httpHandler) handleRequest(ctx context.Context, conn net.Conn, req *htt
 		WithChain(h.chain).
 		WithRetry(h.md.retryCount).
 		WithLogger(h.logger)
-	cc, err := r.Dial(ctx, "tcp", addr)
+	cc, err := r.Dial(ctx, network, addr)
 	if err != nil {
 		resp.StatusCode = http.StatusServiceUnavailable
 		resp.Write(conn)
@@ -209,13 +219,13 @@ func (h *httpHandler) handleRequest(ctx context.Context, conn net.Conn, req *htt
 			h.logger.Debug(string(dump))
 		}
 		if err = resp.Write(conn); err != nil {
-			h.logger.Warn(err)
+			h.logger.Error(err)
 			return
 		}
 	} else {
 		req.Header.Del("Proxy-Connection")
 		if err = req.Write(cc); err != nil {
-			h.logger.Warn(err)
+			h.logger.Error(err)
 			return
 		}
 	}

pkg/handler/http/metadata.go

@@ -13,6 +13,7 @@ type metadata struct {
 	retryCount    int
 	probeResist   *probeResist
 	sni           bool
+	enableUDP     bool
 }
 
 func (h *httpHandler) parseMetadata(md md.Metadata) error {
@@ -23,6 +24,7 @@ func (h *httpHandler) parseMetadata(md md.Metadata) error {
 		knock          = "knock"
 		retryCount     = "retry"
 		sni            = "sni"
+		enableUDP      = "udp"
 	)
 
 	h.md.proxyAgent = md.GetString(proxyAgent)
@@ -53,6 +55,7 @@ func (h *httpHandler) parseMetadata(md md.Metadata) error {
 	}
 	h.md.retryCount = md.GetInt(retryCount)
 	h.md.sni = md.GetBool(sni)
+	h.md.enableUDP = md.GetBool(enableUDP)
 
 	return nil
 }

pkg/handler/http/udp.go

@@ -0,0 +1,83 @@
+package http
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"time"
+
+	"github.com/go-gost/gost/pkg/chain"
+	"github.com/go-gost/gost/pkg/common/util/socks"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+)
+
+func (h *httpHandler) handleUDP(ctx context.Context, conn net.Conn, network, address string) {
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"cmd": "udp",
+	})
+
+	resp := &http.Response{
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     http.Header{},
+	}
+	if h.md.proxyAgent != "" {
+		resp.Header.Add("Proxy-Agent", h.md.proxyAgent)
+	}
+
+	if !h.md.enableUDP {
+		resp.StatusCode = http.StatusForbidden
+		resp.Write(conn)
+
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			dump, _ := httputil.DumpResponse(resp, false)
+			h.logger.Debug(string(dump))
+		}
+		h.logger.Error("UDP relay is diabled")
+
+		return
+	}
+
+	resp.StatusCode = http.StatusOK
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		dump, _ := httputil.DumpResponse(resp, false)
+		h.logger.Debug(string(dump))
+	}
+	if err := resp.Write(conn); err != nil {
+		h.logger.Error(err)
+		return
+	}
+
+	// obtain a udp connection
+	r := (&chain.Router{}).
+		WithChain(h.chain).
+		WithRetry(h.md.retryCount).
+		WithLogger(h.logger)
+	c, err := r.Dial(ctx, "udp", "") // UDP association
+	if err != nil {
+		h.logger.Error(err)
+		return
+	}
+	defer c.Close()
+
+	pc, ok := c.(net.PacketConn)
+	if !ok {
+		h.logger.Errorf("wrong connection type")
+		return
+	}
+
+	relay := handler.NewUDPRelay(socks.UDPTunServerConn(conn), pc).
+		WithBypass(h.bypass).
+		WithLogger(h.logger)
+
+	t := time.Now()
+	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), pc.LocalAddr())
+	relay.Run()
+	h.logger.
+		WithFields(map[string]interface{}{
+			"duration": time.Since(t),
+		}).
+		Infof("%s >-< %s", conn.RemoteAddr(), pc.LocalAddr())
+}