legacy: get next u2f counter

legacy/firmware/fsm.h

@@ -65,6 +65,7 @@ void fsm_msgApplyFlags(const ApplyFlags *msg);
 void fsm_msgRecoveryDevice(const RecoveryDevice *msg);
 void fsm_msgWordAck(const WordAck *msg);
 void fsm_msgSetU2FCounter(const SetU2FCounter *msg);
+void fsm_msgGetNextU2FCounter(void);
 
 // coin
 void fsm_msgGetPublicKey(const GetPublicKey *msg);

legacy/firmware/fsm_msg_common.h

@@ -430,3 +430,21 @@ void fsm_msgSetU2FCounter(const SetU2FCounter *msg) {
   fsm_sendSuccess(_("U2F counter set"));
   layoutHome();
 }
+
+void fsm_msgGetNextU2FCounter() {
+  layoutDialogSwipe(&bmp_icon_question, _("Cancel"), _("Confirm"), NULL,
+                    _("Do you want to"), _("increase and retrieve"),
+                    _("the U2F counter?"), NULL, NULL, NULL);
+  if (!protectButton(ButtonRequestType_ButtonRequest_ProtectCall, false)) {
+    fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
+    layoutHome();
+    return;
+  }
+  uint32_t counter = config_nextU2FCounter();
+
+  RESP_INIT(NextU2FCounter);
+  resp->has_u2f_counter = true;
+  resp->u2f_counter = counter;
+  msg_write(MessageType_MessageType_NextU2FCounter, resp);
+  layoutHome();
+}