websocket: move the process to validate client's frame into method

This is to minimize duplicate code on server's reader and handling
chopped frame.

1 files changed, 36 insertions, 46 deletions

diff --git a/lib/websocket/server.go b/lib/websocket/server.go
index 6d6d25ec..1679761b 100644
--- a/lib/websocket/server.go
+++ b/lib/websocket/server.go
@@ -404,22 +404,7 @@ func (serv *Server) handleChopped(x, conn int, packet []byte) (rest []byte, isCl
 		serv.Clients.setFrame(conn, nil)
 	}
 
-	if frame.masked != frameIsMasked {
-		serv.handleBadRequest(conn)
-		isClosing = true
-		return
-	}
-	if frame.rsv1 > 0 && !serv.allowRsv1 {
-		serv.handleBadRequest(conn)
-		isClosing = true
-		return
-	}
-	if frame.rsv2 > 0 && !serv.allowRsv2 {
-		serv.handleBadRequest(conn)
-		isClosing = true
-		return
-	}
-	if frame.rsv3 > 0 && !serv.allowRsv3 {
+	if !serv.isValidFrame(frame) {
 		serv.handleBadRequest(conn)
 		isClosing = true
 		return
@@ -736,6 +721,40 @@ func (serv *Server) handlePing(conn int, req *Frame) {
 }
 
 //
+// isValidFrame will return true if a frame from client is valid:
+// it's masked, the reserved bits is not set (unless allowed by server), and
+// if its control frame the fin should be set and payload must be less than
+// 125.
+//
+func (serv *Server) isValidFrame(frame *Frame) bool {
+	if frame.masked != frameIsMasked {
+		return false
+	}
+	if frame.rsv1 > 0 && !serv.allowRsv1 {
+		return false
+	}
+	if frame.rsv2 > 0 && !serv.allowRsv2 {
+		return false
+	}
+	if frame.rsv3 > 0 && !serv.allowRsv3 {
+		return false
+	}
+
+	if frame.opcode == OpcodeClose || frame.opcode == OpcodePing || frame.opcode == OpcodePong {
+		if frame.fin == 0 {
+			// Control frame must set the fin.
+			return false
+		}
+		// Control frame payload must not larger than 125.
+		if frame.len > frameSmallPayload {
+			return false
+		}
+	}
+
+	return true
+}
+
+//
 // reader read request from client.
 //
 // To avoid confusing network intermediaries (such as intercepting proxies)
@@ -797,40 +816,11 @@ func (serv *Server) reader() {
 					continue
 				}
 
-				if frame.masked != frameIsMasked {
-					serv.handleBadRequest(conn)
-					isClosing = true
-					break
-				}
-				if frame.rsv1 > 0 && !serv.allowRsv1 {
+				if !serv.isValidFrame(frame) {
 					serv.handleBadRequest(conn)
 					isClosing = true
 					break
 				}
-				if frame.rsv2 > 0 && !serv.allowRsv2 {
-					serv.handleBadRequest(conn)
-					isClosing = true
-					break
-				}
-				if frame.rsv3 > 0 && !serv.allowRsv3 {
-					serv.handleBadRequest(conn)
-					isClosing = true
-					break
-				}
-				if frame.opcode == OpcodeClose || frame.opcode == OpcodePing || frame.opcode == OpcodePong {
-					if frame.fin == 0 {
-						// Control frame must set the fin.
-						serv.handleBadRequest(conn)
-						isClosing = true
-						break
-					}
-					// Control frame payload must not larger than 125.
-					if frame.len > frameSmallPayload {
-						serv.handleBadRequest(conn)
-						isClosing = true
-						break
-					}
-				}
 
 				switch frame.opcode {
 				case OpcodeCont, OpcodeText, OpcodeBin: