Make pipe read timeout configurable via idleTimeout metadata

The 30s hardcoded readTimeout in Pipe() caused all CONNECT tunnel
connections to be hard-closed after 30s of inactivity, breaking
WebSocket and long-polling connections through the proxy.

Pipe() now accepts a WithReadTimeout(d) option. When d is 0 (the
default) no read deadline is set, relying on TCP keepalives or context
cancellation to detect dead connections instead.

The HTTP handler exposes this as the idleTimeout metadata key.

Fixes: https://github.com/go-gost/x/issues/91

internal/net/pipe.go

@@ -12,11 +12,32 @@ import (
 const (
 	// tcpWaitTimeout implements a TCP half-close timeout.
 	tcpWaitTimeout = 10 * time.Second
-	readTimeout    = 30 * time.Second
 )
 
+// PipeOption configures the behaviour of Pipe.
+type PipeOption func(*pipeOptions)
+
+type pipeOptions struct {
+	readTimeout time.Duration
+}
+
+// WithReadTimeout sets an idle read timeout on each pipe half. When a read
+// blocks for longer than d the connection is closed. A value of 0 disables
+// the timeout entirely, relying on TCP keepalives or context cancellation to
+// detect dead connections.
+func WithReadTimeout(d time.Duration) PipeOption {
+	return func(o *pipeOptions) {
+		o.readTimeout = d
+	}
+}
+
 // Pipe 在两个连接之间建立双向数据通道
-func Pipe(ctx context.Context, rw1, rw2 io.ReadWriteCloser) error {
+func Pipe(ctx context.Context, rw1, rw2 io.ReadWriteCloser, opts ...PipeOption) error {
+	var options pipeOptions
+	for _, opt := range opts {
+		opt(&options)
+	}
+
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
@@ -24,11 +45,11 @@ func Pipe(ctx context.Context, rw1, rw2 io.ReadWriteCloser) error {
 
 	// 启动两个方向的传输
 	go func() {
-		errCh <- pipeHalf(ctx, rw1, rw2)
+		errCh <- pipeHalf(ctx, rw1, rw2, options.readTimeout)
 	}()
 
 	go func() {
-		errCh <- pipeHalf(ctx, rw2, rw1)
+		errCh <- pipeHalf(ctx, rw2, rw1, options.readTimeout)
 	}()
 
 	// 等待第一个错误或完成
@@ -51,7 +72,7 @@ func Pipe(ctx context.Context, rw1, rw2 io.ReadWriteCloser) error {
 }
 
 // pipeHalf 单向管道传输
-func pipeHalf(ctx context.Context, src, dst io.ReadWriteCloser) error {
+func pipeHalf(ctx context.Context, src, dst io.ReadWriteCloser, readTimeout time.Duration) error {
 	defer func() {
 		// 传输完成后执行TCP半关闭
 		halfClose(src, dst)
@@ -60,7 +81,6 @@ func pipeHalf(ctx context.Context, src, dst io.ReadWriteCloser) error {
 	buf := bufpool.Get(bufferSize / 2)
 	defer bufpool.Put(buf)
 
-
 	// 创建带超时的读取器
 	reader := &readDeadliner{
 		Reader: src,
@@ -73,9 +93,11 @@ func pipeHalf(ctx context.Context, src, dst io.ReadWriteCloser) error {
 		case <-ctx.Done():
 			return ctx.Err()
 		default:
-			// 设置读取超时
-			if rd, ok := src.(interface{ SetReadDeadline(time.Time) error }); ok {
-				rd.SetReadDeadline(time.Now().Add(readTimeout))
+			// 设置读取超时 (仅当配置了超时时)
+			if readTimeout > 0 {
+				if rd, ok := src.(interface{ SetReadDeadline(time.Time) error }); ok {
+					rd.SetReadDeadline(time.Now().Add(readTimeout))
+				}
 			}
 
 			// 读取数据