Fix crash when KRPC messages don't contain a valid "t" field

diff --git a/dht/dht.go b/dht/dht.go
index 61a0eb2cc244ae51fabc9d42adc5d7f80e5188c8..cd8f9e358c4e83fe7f79b21b0b4fe9637800cd89 100644 (file)
--- a/dht/dht.go
+++ b/dht/dht.go
@@ -64,6 +64,15 @@ func (m Msg) String() string {
        return fmt.Sprintf("%#v", m)
 }
 
+func (m Msg) T() (t string) {
+       tif, ok := m["t"]
+       if !ok {
+               return
+       }
+       t, _ = tif.(string)
+       return
+}
+
 type transaction struct {
        remoteAddr net.Addr
        t          string
@@ -128,7 +137,7 @@ func (s *Server) Serve() error {
                if err != nil {
                        return err
                }
-               var d map[string]interface{}
+               var d Msg
                err = bencode.Unmarshal(b[:n], &d)
                if err != nil {
                        log.Printf("%s: received bad krpc message: %s: %q", s, err, b[:n])
@@ -140,7 +149,7 @@ func (s *Server) Serve() error {
                        s.mu.Unlock()
                        continue
                }
-               t := s.findResponseTransaction(d["t"].(string), addr)
+               t := s.findResponseTransaction(d.T(), addr)
                if t == nil {
                        //log.Printf("unexpected message: %#v", d)
                        s.mu.Unlock()