Fix: panic when DisableApi is set

psiphon/tunnel.go

@@ -1010,40 +1010,41 @@ func (tunnel *Tunnel) operateTunnel(tunnelOwner TunnelOwner) {
 	// Always emit a final NoticeTotalBytesTransferred
 	NoticeTotalBytesTransferred(tunnel.serverEntry.IpAddress, totalSent, totalReceived)
 
-	// The stats for this tunnel will be reported via the next successful
-	// status request.
-
-	// Since client clocks are unreliable, we report the server's timestamp from
-	// the handshake response as the absolute tunnel start time. This time
-	// will be slightly earlier than the actual tunnel activation time, as the
-	// client has to receive and parse the response and activate the tunnel.
-
-	tunnelStartTime := tunnel.serverContext.serverHandshakeTimestamp
-
-	// For the tunnel duration calculation, we use the local clock. The start time
-	// is tunnel.establishedTime as recorded when the tunnel was established. For the
-	// end time, we do not use the current time as we may now be long past the
-	// actual termination time of the tunnel. For example, the host or device may
-	// have resumed after a long sleep (it's not clear that the monotonic clock service
-	// used to measure elapsed time will or will not stop during device sleep). Instead,
-	// we use the last data received time as the estimated tunnel end time.
-	//
-	// One potential issue with using the last received time is receiving data
-	// after an extended sleep because the device sleep occured with data still in
-	// the OS socket read buffer. This is not expected to happen on Android, as the
-	// OS will wake a process when it has TCP data available to read. (For this reason,
-	// the actual long sleep issue is only with an idle tunnel; in this case the client
-	// is responsible for sending SSH keep alives but a device sleep will delay the
-	// golang SSH keep alive timer.)
-	//
-	// Idle tunnels will only read data when a SSH keep alive is sent. As a result,
-	// the last-received-time scheme can undercount tunnel durations by up to
-	// TUNNEL_SSH_KEEP_ALIVE_PERIOD_MAX for idle tunnels.
-
-	tunnelDuration := tunnel.conn.GetLastActivityMonotime().Sub(tunnel.establishedTime)
-
 	// Tunnel does not have a serverContext when DisableApi is set.
 	if tunnel.serverContext != nil && !tunnel.IsDiscarded() {
+
+		// The stats for this tunnel will be reported via the next successful
+		// status request.
+
+		// Since client clocks are unreliable, we report the server's timestamp from
+		// the handshake response as the absolute tunnel start time. This time
+		// will be slightly earlier than the actual tunnel activation time, as the
+		// client has to receive and parse the response and activate the tunnel.
+
+		tunnelStartTime := tunnel.serverContext.serverHandshakeTimestamp
+
+		// For the tunnel duration calculation, we use the local clock. The start time
+		// is tunnel.establishedTime as recorded when the tunnel was established. For the
+		// end time, we do not use the current time as we may now be long past the
+		// actual termination time of the tunnel. For example, the host or device may
+		// have resumed after a long sleep (it's not clear that the monotonic clock service
+		// used to measure elapsed time will or will not stop during device sleep). Instead,
+		// we use the last data received time as the estimated tunnel end time.
+		//
+		// One potential issue with using the last received time is receiving data
+		// after an extended sleep because the device sleep occured with data still in
+		// the OS socket read buffer. This is not expected to happen on Android, as the
+		// OS will wake a process when it has TCP data available to read. (For this reason,
+		// the actual long sleep issue is only with an idle tunnel; in this case the client
+		// is responsible for sending SSH keep alives but a device sleep will delay the
+		// golang SSH keep alive timer.)
+		//
+		// Idle tunnels will only read data when a SSH keep alive is sent. As a result,
+		// the last-received-time scheme can undercount tunnel durations by up to
+		// TUNNEL_SSH_KEEP_ALIVE_PERIOD_MAX for idle tunnels.
+
+		tunnelDuration := tunnel.conn.GetLastActivityMonotime().Sub(tunnel.establishedTime)
+
 		err := RecordTunnelStats(
 			tunnel.serverContext.sessionId,
 			tunnel.serverContext.tunnelNumber,