rpc: Do not use read/write deadlines for rpc connections. (#4647)

Fixes #4626

cmd/rpc-server.go

@@ -0,0 +1,58 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"io"
+	"net/http"
+	"net/rpc"
+
+	miniohttp "github.com/minio/minio/pkg/http"
+)
+
+// ServeHTTP implements an http.Handler that answers RPC requests,
+// hijacks the underlying connection and clears all deadlines if any.
+func (server *rpcServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if req.Method != http.MethodConnect {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+
+	conn, _, err := w.(http.Hijacker).Hijack()
+	if err != nil {
+		errorIf(err, "rpc hijacking failed for: %s", req.RemoteAddr)
+		return
+	}
+
+	// Overrides Read/Write deadlines if any.
+	bufConn, ok := conn.(*miniohttp.BufConn)
+	if ok {
+		bufConn.RemoveTimeout()
+		conn = bufConn
+	}
+
+	// Can connect to RPC service using HTTP CONNECT to rpcPath.
+	io.WriteString(conn, "HTTP/1.0 200 Connected to Go RPC\n\n")
+	server.ServeConn(conn)
+}
+
+type rpcServer struct{ *rpc.Server }
+
+// Similar to rpc.NewServer() provides a custom ServeHTTP override.
+func newRPCServer() *rpcServer {
+	return &rpcServer{rpc.NewServer()}
+}