get doorbot to handle lack of networking as fail-secure

previously, with no connectivity to a working acserver  process,
it would misinterpret network failures as a grant of access for any card, (and it
would cache that card for 8 hours)
acserver wasn't a problem.

Author: Simon Hewison

src/doorbot.cpp

@@ -43,6 +43,9 @@ void Doorbot::handleCardPresent(Card c) {
     case -1:
         denyAccess();
       break;
+    case -99:
+        networkingError();
+        break;
     default:
       cache->set(c);
       grantAccess();
@@ -68,3 +71,18 @@ void Doorbot::denyAccess() {
 void Doorbot::grantAccess() {
   door.open();
 }
+
+void Doorbot::networkingError() {
+  // Captain, these lights are blinking out of sequence. What shall we do?
+  // Get them to blink in sequence!
+  // We have a networking error, so blink RED/BLUE/RED/BLUE to highlight some problem
+  led.solid(RED);
+  delay(ACCESS_DENIED_LED_ON_TIME/4);
+  led.solid(BLUE);
+  delay(ACCESS_DENIED_LED_ON_TIME/4);
+  led.solid(RED);
+  delay(ACCESS_DENIED_LED_ON_TIME/4);
+  led.solid(BLUE);
+  delay(ACCESS_DENIED_LED_ON_TIME/4);
+  led.solid(BLACK);
+}

src/doorbot.h

@@ -21,6 +21,7 @@ class Doorbot : public Role {
     Doorbot(Door &, Watchdog &, PN532 &, RGB &l);
     void enableAnnouncer(uint16_t port);
     void run();
+    void networkingError();
   protected:
     void handleCardPresent(Card c);
     void denyAccess();