logging: add error to udp logs

This also makes the format of UDP and HTTP logs a little more similar.

http/http.go

@@ -34,12 +34,11 @@ type Server struct {
 // stats, logging, and handling errors.
 func makeHandler(handler ResponseHandler) httprouter.Handle {
 	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
-		var msg string
-
 		start := time.Now()
 		httpCode, err := handler(w, r, p)
 		duration := time.Since(start)
 
+		var msg string
 		if err != nil {
 			msg = err.Error()
 		} else if httpCode != http.StatusOK {
@@ -58,9 +57,9 @@ func makeHandler(handler ResponseHandler) httprouter.Handle {
 			}
 
 			if len(msg) > 0 {
-				glog.Errorf("[%d - %9s] %s (%s)", httpCode, duration, reqString, msg)
+				glog.Errorf("[HTTP - %9s] %s (%d - %s)", duration, reqString, httpCode, msg)
 			} else {
-				glog.Infof("[%d - %9s] %s", httpCode, duration, reqString)
+				glog.Infof("[HTTP - %9s] %s (%d)", duration, reqString, httpCode)
 			}
 		}
 

udp/protocol.go

@@ -62,9 +62,12 @@ func handleTorrentError(err error, w *Writer) {
 }
 
 // handlePacket decodes and processes one UDP request, returning the response.
-func (s *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte, actionName string) {
+func (s *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte, actionName string, err error) {
 	if len(packet) < 16 {
-		return // Malformed, no client packets are less than 16 bytes.
+		// Malformed, no client packets are less than 16 bytes.
+		// We explicitly return nothing in case this is a DoS attempt.
+		err = errMalformedPacket
+		return
 	}
 
 	connID := packet[0:8]
@@ -80,15 +83,18 @@ func (s *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte
 	defer func() { response = writer.buf.Bytes() }()
 
 	if action != 0 && !s.connIDGen.Matches(connID, addr.IP) {
-		writer.WriteError(errBadConnectionID)
+		err = errBadConnectionID
+		writer.WriteError(err)
 		return
 	}
 
 	switch action {
 	case connectActionID:
 		actionName = "connect"
+
 		if !bytes.Equal(connID, initialConnectionID) {
-			return // Malformed packet.
+			err = errMalformedPacket
+			return
 		}
 
 		writer.writeHeader(0)
@@ -96,8 +102,9 @@ func (s *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte
 
 	case announceActionID:
 		actionName = "announce"
-		ann, err := s.newAnnounce(packet, addr.IP)
 
+		var ann *models.Announce
+		ann, err = s.newAnnounce(packet, addr.IP)
 		if err == nil {
 			err = s.tracker.HandleAnnounce(ann, writer)
 		}
@@ -106,8 +113,9 @@ func (s *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte
 
 	case scrapeActionID:
 		actionName = "scrape"
-		scrape, err := s.newScrape(packet)
 
+		var scrape *models.Scrape
+		scrape, err = s.newScrape(packet)
 		if err == nil {
 			err = s.tracker.HandleScrape(scrape, writer)
 		}

udp/udp.go

@@ -68,20 +68,23 @@ func (s *Server) serve(listenAddr string) error {
 			return err
 		}
 
-		start := time.Now()
-
 		go func() {
-			response, action := s.handlePacket(buffer[:n], addr)
+			start := time.Now()
-			pool.GiveSlice(buffer)
+			response, action, err := s.handlePacket(buffer[:n], addr)
+			defer pool.GiveSlice(buffer)
+			duration := time.Since(start)
 
 			if len(response) > 0 {
 				sock.WriteToUDP(response, addr)
 			}
 
 			if glog.V(2) {
-				duration := time.Since(start)
+				if err != nil {
+					glog.Infof("[UDP - %9s] %s %s (%s)", duration, action, addr, err)
+				} else {
 					glog.Infof("[UDP - %9s] %s %s", duration, action, addr)
 				}
+			}
 		}()
 	}