Fixes to UDP so that it no longer has socket 0 hardcoded - all part of issue #436

libraries/Ethernet/Client.cpp

@@ -77,14 +77,25 @@ int Client::available() {
 
 int Client::read() {
   uint8_t b;
-  if (!available())
+  if ( recv(_sock, &b, 1) > 0 )
+  {
+    // recv worked
+    return b;
+  }
+  else
+  {
+    // No data available
     return -1;
-  recv(_sock, &b, 1);
-  return b;
+  }
+}
+
+int Client::read(uint8_t *buf, size_t size) {
+  return recv(_sock, buf, size);
 }
 
 int Client::peek() {
   uint8_t b;
+  // Unlike recv, peek doesn't check to see if there's any data available, so we must
   if (!available())
     return -1;
   ::peek(_sock, &b);

libraries/Ethernet/Client.h

@@ -17,6 +17,7 @@ class Client : public Stream {
   virtual void write(const uint8_t *buf, size_t size);
   virtual int available();
   virtual int read();
+  virtual int read(uint8_t *buf, size_t size);
   virtual int peek();
   virtual void flush();
   void stop();

libraries/Ethernet/utility/socket.cpp

@@ -146,13 +146,32 @@ uint16_t send(SOCKET s, const uint8_t * buf, uint16_t len)
  */
 uint16_t recv(SOCKET s, uint8_t *buf, uint16_t len)
 {
-  uint16_t ret=0;
+  // Check how much data is available
+  uint16_t ret = W5100.getRXReceivedSize(s);
+  if ( ret == 0 )
+  {
+    // No data available.
+    uint8_t status = W5100.readSnSR(s);
+    if ( s == SnSR::LISTEN || s == SnSR::CLOSED || s == SnSR::CLOSE_WAIT )
+    {
+      // The remote end has closed its side of the connection, so this is the eof state
+      ret = 0;
+    }
+    else
+    {
+      // The connection is still up, but there's no data waiting to be read
+      ret = -1;
+    }
+  }
+  else if (ret > len)
+  {
+    ret = len;
+  }
 
-  if ( len > 0 )
+  if ( ret > 0 )
   {
-    W5100.recv_data_processing(s, buf, len);
+    W5100.recv_data_processing(s, buf, ret);
     W5100.execCmdSn(s, Sock_RECV);
-    ret = len;
   }
   return ret;
 }