make GetSessions use the session workers to avoid races

src/yggdrasil/api.go

@@ -211,7 +211,8 @@ func (c *Core) GetSessions() []Session {
 	var sessions []Session
 	getSessions := func() {
 		for _, sinfo := range c.sessions.sinfos {
-			// TODO? skipped known but timed out sessions?
+			var session Session
+			workerFunc := func() {
 				session := Session{
 					Coords:      append([]byte{}, sinfo.coords...),
 					MTU:         sinfo.getMTU(),
@@ -221,6 +222,20 @@ func (c *Core) GetSessions() []Session {
 					WasMTUFixed: sinfo.wasMTUFixed,
 				}
 				copy(session.PublicKey[:], sinfo.theirPermPub[:])
+			}
+			var skip bool
+			func() {
+				defer func() {
+					if recover() != nil {
+						skip = true
+					}
+				}()
+				sinfo.doWorker(workerFunc)
+			}()
+			if skip {
+				continue
+			}
+			// TODO? skipped known but timed out sessions?
 			sessions = append(sessions, session)
 		}
 	}