lit: only fetch active sessions on startup

Using the new ListSessions by type method, we no longer need to fetch
and iterate through all our sessions on start up to figure out which
ones to spin up.

session_rpcserver.go

@@ -100,7 +100,10 @@ func newSessionRPCServer(cfg *sessionRpcServerConfig) (*sessionRpcServer,
 // requests. This includes resuming all non-revoked sessions.
 func (s *sessionRpcServer) start(ctx context.Context) error {
 	// Start up all previously created sessions.
-	sessions, err := s.cfg.db.ListSessions()
+	sessions, err := s.cfg.db.ListSessions(
+		session.StateCreated,
+		session.StateInUse,
+	)
 	if err != nil {
 		return fmt.Errorf("error listing sessions: %v", err)
 	}
@@ -356,16 +359,6 @@ func (s *sessionRpcServer) resumeSession(ctx context.Context,
 	pubKey := sess.LocalPublicKey
 	pubKeyBytes := pubKey.SerializeCompressed()
 
-	// We only start non-revoked, non-expired LiT sessions. Everything else
-	// we just skip.
-	if sess.State != session.StateInUse &&
-		sess.State != session.StateCreated {
-
-		log.Debugf("Not resuming session %x with state %d", pubKeyBytes,
-			sess.State)
-		return nil
-	}
-
 	// Don't resume an expired session.
 	if sess.Expiry.Before(time.Now()) {
 		log.Debugf("Not resuming session %x with expiry %s",