From 34c3d1076795e53941b6b06f0770910c8ab62bf3 Mon Sep 17 00:00:00 2001
From: Bruno Crivelari Sanches <bcsanches@gmail.com>
Date: Sat, 3 Sep 2022 17:16:33 -0300
Subject: [PATCH] Keep Ethernet singleton "alive" until connection is
 established.

---
 EthernetInterface.cpp | 70 +++++++++++++++++++++----------------------
 EthernetInterface.h   |  3 ++
 2 files changed, 38 insertions(+), 35 deletions(-)

diff --git a/EthernetInterface.cpp b/EthernetInterface.cpp
index f691f45..9d04423 100644
--- a/EthernetInterface.cpp
+++ b/EthernetInterface.cpp
@@ -36,7 +36,15 @@ EthernetInterface * EthernetInterface::singleton=NULL;
 void EthernetInterface::setup()
 {
     singleton=new EthernetInterface();
-    if (!singleton->connected) singleton=NULL; 
+
+    DIAG(F("Ethernet begin OK."));
+     if (Ethernet.hardwareStatus() == EthernetNoHardware) {
+      DIAG(F("Ethernet shield not found"));
+
+      singleton=NULL;
+
+      return;
+    }     
 };
 
 
@@ -60,38 +68,7 @@ EthernetInterface::EthernetInterface()
         DIAG(F("Ethernet.begin FAILED"));
         return;
     } 
-    #endif
-    DIAG(F("begin OK."));
-     if (Ethernet.hardwareStatus() == EthernetNoHardware) {
-      DIAG(F("Ethernet shield not found"));
-      return;
-    }
-  
-    unsigned long startmilli = millis();
-    while ((millis() - startmilli) < 5500) // Loop to give time to check for cable connection
-    {
-        if (Ethernet.linkStatus() == LinkON)
-            break;
-        DIAG(F("Ethernet waiting for link (1sec) "));
-        delay(1000);
-    }
-
-    if (Ethernet.linkStatus() == LinkOFF) {
-      DIAG(F("Ethernet cable not connected"));
-      return;
-    }
-    
-    connected=true;
-    
-    IPAddress ip = Ethernet.localIP(); // reassign the obtained ip address
-
-    server = new EthernetServer(IP_PORT); // Ethernet Server listening on default port IP_PORT
-    server->begin();
-  
-    LCD(4,F("IP: %d.%d.%d.%d"), ip[0], ip[1], ip[2], ip[3]);
-    LCD(5,F("Port:%d"), IP_PORT);
-
-    outboundRing=new RingStream(OUTBOUND_RING_SIZE);     
+    #endif       
 }
 
 /**
@@ -99,8 +76,9 @@ EthernetInterface::EthernetInterface()
  * 
  */
 void EthernetInterface::loop()
-{
-    if (!singleton) return;
+{    
+    if(!singleton || ((!singleton->connected) && (!singleton->checkLink())))
+        return;
     
     switch (Ethernet.maintain())
     {
@@ -125,6 +103,28 @@ void EthernetInterface::loop()
 
 }
 
+bool EthernetInterface::checkLink()
+{    
+    if (Ethernet.linkStatus() != LinkON)
+        return false;
+
+    DIAG(F("Ethernet cable connected"));
+    
+    connected=true;
+    
+    IPAddress ip = Ethernet.localIP(); // reassign the obtained ip address
+
+    server = new EthernetServer(IP_PORT); // Ethernet Server listening on default port IP_PORT
+    server->begin();
+  
+    LCD(4,F("IP: %d.%d.%d.%d"), ip[0], ip[1], ip[2], ip[3]);
+    LCD(5,F("Port:%d"), IP_PORT);
+
+    outboundRing=new RingStream(OUTBOUND_RING_SIZE);   
+
+    return true;
+}
+
  void EthernetInterface::loop2()
 {
     // get client from the server
diff --git a/EthernetInterface.h b/EthernetInterface.h
index 2a94ac6..ff673c1 100644
--- a/EthernetInterface.h
+++ b/EthernetInterface.h
@@ -60,6 +60,9 @@ class EthernetInterface {
      bool connected;
      EthernetInterface();
      void loop2();
+
+     bool checkLink();
+
     EthernetServer * server;
     EthernetClient clients[MAX_SOCK_NUM];                // accept up to MAX_SOCK_NUM client connections at the same time; This depends on the chipset used on the Shield
     uint8_t buffer[MAX_ETH_BUFFER+1];                    // buffer used by TCP for the recv