Created an abstract base class UDP to match the Client and Server classes, and reworked the Ethernet library to use it and derive EthernetUDP.

Author: amcewen

hardware/arduino/cores/arduino/Udp.h

@@ -0,0 +1,90 @@
+/*
+ *  Udp.cpp: Library to send/receive UDP packets.
+ *
+ * NOTE: UDP is fast, but has some important limitations (thanks to Warren Gray for mentioning these)
+ * 1) UDP does not guarantee the order in which assembled UDP packets are received. This
+ * might not happen often in practice, but in larger network topologies, a UDP
+ * packet can be received out of sequence. 
+ * 2) UDP does not guard against lost packets - so packets *can* disappear without the sender being
+ * aware of it. Again, this may not be a concern in practice on small local networks.
+ * For more information, see http://www.cafeaulait.org/course/week12/35.html
+ *
+ * MIT License:
+ * Copyright (c) 2008 Bjoern Hartmann
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * bjoern@cs.stanford.edu 12/30/2008
+ */
+
+#ifndef udp_h
+#define udp_h
+
+#include <Stream.h>
+#include <IPAddress.h>
+
+class UDP : public Stream {
+
+public:
+  virtual uint8_t begin(uint16_t) =0;	// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
+  virtual void stop() =0;  // Finish with the UDP socket
+
+  // Sending UDP packets
+  
+  // Start building up a packet to send to the remote host specific in ip and port
+  // Returns 1 if successful, 0 if there was a problem with the supplied IP address or port
+  virtual int beginPacket(IPAddress ip, uint16_t port) =0;
+  // Start building up a packet to send to the remote host specific in host and port
+  // Returns 1 if successful, 0 if there was a problem resolving the hostname or port
+  virtual int beginPacket(const char *host, uint16_t port) =0;
+  // Finish off this packet and send it
+  // Returns 1 if the packet was sent successfully, 0 if there was an error
+  virtual int endPacket() =0;
+  // Write a single byte into the packet
+  virtual size_t write(uint8_t) =0;
+  // Write a string of characters into the packet
+  virtual size_t write(const char *str) =0;
+  // Write size bytes from buffer into the packet
+  virtual size_t write(const uint8_t *buffer, size_t size) =0;
+
+  // Start processing the next available incoming packet
+  // Returns the size of the packet in bytes, or 0 if no packets are available
+  virtual int parsePacket() =0;
+  // Number of bytes remaining in the current packet
+  virtual int available() =0;
+  // Read a single byte from the current packet
+  virtual int read() =0;
+  // Read up to len bytes from the current packet and place them into buffer
+  // Returns the number of bytes read, or 0 if none are available
+  virtual int read(unsigned char* buffer, size_t len) =0;
+  // Read up to len characters from the current packet and place them into buffer
+  // Returns the number of characters read, or 0 if none are available
+  virtual int read(char* buffer, size_t len) =0;
+  // Return the next byte from the current packet without moving on to the next byte
+  virtual int peek() =0;
+  virtual void flush() =0;	// Finish reading the current packet
+
+  // Return the IP address of the host who sent the current incoming packet
+  virtual IPAddress remoteIP() =0;
+  // Return the port of the host who sent the current incoming packet
+  virtual uint16_t remotePort() =0;
+protected:
+  uint8_t* rawIPAddress(IPAddress& addr) { return addr.raw_address(); };
+};
+
+#endif

libraries/Ethernet/Dhcp.h

@@ -4,7 +4,7 @@
 #ifndef Dhcp_h
 #define Dhcp_h
 
-#include "Udp.h"
+#include "EthernetUdp.h"
 
 /* DHCP state machine. */
 #define STATE_DHCP_START 0
@@ -139,7 +139,7 @@ class DhcpClass {
   uint8_t  _dhcpGatewayIp[4];
   uint8_t  _dhcpDhcpServerIp[4];
   uint8_t  _dhcpDnsServerIp[4];
-  UDP _dhcpUdpSocket;
+  EthernetUDP _dhcpUdpSocket;
 
   void presend_DHCP();
   void send_DHCP_MESSAGE(uint8_t, uint16_t);

libraries/Ethernet/Dns.cpp

@@ -3,7 +3,7 @@
 // Released under Apache License, version 2.0
 
 #include "w5100.h"
-#include "Udp.h"
+#include "EthernetUdp.h"
 #include "util.h"
 
 #include "Dns.h"

libraries/Ethernet/Dns.h

@@ -5,7 +5,7 @@
 #ifndef DNSClient_h
 #define DNSClient_h
 
-#include <Udp.h>
+#include <EthernetUdp.h>
 
 class DNSClient
 {
@@ -35,7 +35,7 @@ class DNSClient
 
     IPAddress iDNSServer;
     uint16_t iRequestId;
-    UDP iUdp;
+    EthernetUDP iUdp;
 };
 
 #endif

libraries/Ethernet/Udp.cpp renamed to libraries/Ethernet/EthernetUdp.cpp

@@ -33,10 +33,10 @@
 #include "Dns.h"
 
 /* Constructor */
-UDP::UDP() : _sock(MAX_SOCK_NUM) {}
+EthernetUDP::EthernetUDP() : _sock(MAX_SOCK_NUM) {}
 
-/* Start UDP socket, listening at local port PORT */
-uint8_t UDP::begin(uint16_t port) {
+/* Start EthernetUDP socket, listening at local port PORT */
+uint8_t EthernetUDP::begin(uint16_t port) {
   if (_sock != MAX_SOCK_NUM)
     return 0;
 
@@ -59,12 +59,12 @@ uint8_t UDP::begin(uint16_t port) {
 
 /* Is data available in rx buffer? Returns 0 if no, number of available bytes if yes. 
  * returned value includes 8 byte UDP header!*/
-int UDP::available() {
+int EthernetUDP::available() {
   return W5100.getRXReceivedSize(_sock);
 }
 
-/* Release any resources being used by this UDP instance */
-void UDP::stop()
+/* Release any resources being used by this EthernetUDP instance */
+void EthernetUDP::stop()
 {
   if (_sock == MAX_SOCK_NUM)
     return;
@@ -75,7 +75,7 @@ void UDP::stop()
   _sock = MAX_SOCK_NUM;
 }
 
-int UDP::beginPacket(const char *host, uint16_t port)
+int EthernetUDP::beginPacket(const char *host, uint16_t port)
 {
   // Look up the host first
   int ret = 0;
@@ -91,36 +91,36 @@ int UDP::beginPacket(const char *host, uint16_t port)
   }
 }
 
-int UDP::beginPacket(IPAddress ip, uint16_t port)
+int EthernetUDP::beginPacket(IPAddress ip, uint16_t port)
 {
   _offset = 0;
-  return startUDP(_sock, ip.raw_address(), port);
+  return startUDP(_sock, rawIPAddress(ip), port);
 }
 
-int UDP::endPacket()
+int EthernetUDP::endPacket()
 {
   return sendUDP(_sock);
 }
 
-size_t UDP::write(uint8_t byte)
+size_t EthernetUDP::write(uint8_t byte)
 {
   return write(&byte, 1);
 }
 
-size_t UDP::write(const char *str)
+size_t EthernetUDP::write(const char *str)
 {
   size_t len = strlen(str);
   return write((const uint8_t *)str, len);
 }
 
-size_t UDP::write(const uint8_t *buffer, size_t size)
+size_t EthernetUDP::write(const uint8_t *buffer, size_t size)
 {
   uint16_t bytes_written = bufferData(_sock, _offset, buffer, size);
   _offset += bytes_written;
   return bytes_written;
 }
 
-int UDP::parsePacket()
+int EthernetUDP::parsePacket()
 {
   if (available() > 0)
   {
@@ -143,7 +143,7 @@ int UDP::parsePacket()
   return 0;
 }
 
-int UDP::read()
+int EthernetUDP::read()
 {
   uint8_t byte;
   if (recv(_sock, &byte, 1) > 0)
@@ -155,7 +155,7 @@ int UDP::read()
   return -1;
 }
 
-int UDP::read(unsigned char* buffer, size_t len)
+int EthernetUDP::read(unsigned char* buffer, size_t len)
 {
   /* In the readPacket that copes with truncating packets, the buffer was
      filled with this code.  Not sure why it loops round reading out a byte
@@ -169,7 +169,7 @@ int UDP::read(unsigned char* buffer, size_t len)
   return recv(_sock, buffer, len);
 }
 
-int UDP::peek()
+int EthernetUDP::peek()
 {
   uint8_t b;
   // Unlike recv, peek doesn't check to see if there's any data available, so we must
@@ -179,7 +179,7 @@ int UDP::peek()
   return b;
 }
 
-void UDP::flush()
+void EthernetUDP::flush()
 {
   while (available())
   {

libraries/Ethernet/Udp.h renamed to libraries/Ethernet/EthernetUdp.h

@@ -34,15 +34,14 @@
  * bjoern@cs.stanford.edu 12/30/2008
  */
 
-#ifndef udp_h
-#define udp_h
+#ifndef ethernetudp_h
+#define ethernetudp_h
 
-#include <Stream.h>
-#include <IPAddress.h>
+#include <Udp.h>
 
 #define UDP_TX_PACKET_MAX_SIZE 24
 
-class UDP : public Stream {
+class EthernetUDP : public UDP {
 private:
   uint8_t _sock;  // socket ID for Wiz5100
   uint16_t _port; // local port to listen on
@@ -51,21 +50,21 @@ class UDP : public Stream {
   uint16_t _offset; // offset into the packet being sent
 
 public:
-  UDP();  // Constructor
-  uint8_t begin(uint16_t);	// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
-  void stop();  // Finish with the UDP socket
+  EthernetUDP();  // Constructor
+  virtual uint8_t begin(uint16_t);	// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
+  virtual void stop();  // Finish with the UDP socket
 
   // Sending UDP packets
 
   // Start building up a packet to send to the remote host specific in ip and port
   // Returns 1 if successful, 0 if there was a problem with the supplied IP address or port
-  int beginPacket(IPAddress ip, uint16_t port);
+  virtual int beginPacket(IPAddress ip, uint16_t port);
   // Start building up a packet to send to the remote host specific in host and port
   // Returns 1 if successful, 0 if there was a problem resolving the hostname or port
-  int beginPacket(const char *host, uint16_t port);
+  virtual int beginPacket(const char *host, uint16_t port);
   // Finish off this packet and send it
   // Returns 1 if the packet was sent successfully, 0 if there was an error
-  int endPacket();
+  virtual int endPacket();
   // Write a single byte into the packet
   virtual size_t write(uint8_t);
   // Write a string of characters into the packet
@@ -75,7 +74,7 @@ class UDP : public Stream {
 
   // Start processing the next available incoming packet
   // Returns the size of the packet in bytes, or 0 if no packets are available
-  int parsePacket();
+  virtual int parsePacket();
   // Number of bytes remaining in the current packet
   virtual int available();
   // Read a single byte from the current packet
@@ -91,9 +90,9 @@ class UDP : public Stream {
   virtual void flush();	// Finish reading the current packet
 
   // Return the IP address of the host who sent the current incoming packet
-  IPAddress remoteIP() { return _remoteIP; };
+  virtual IPAddress remoteIP() { return _remoteIP; };
   // Return the port of the host who sent the current incoming packet
-  uint16_t remotePort() { return _remotePort; };
+  virtual uint16_t remotePort() { return _remotePort; };
 };
 
 #endif

libraries/Ethernet/examples/UDPSendReceiveString/UDPSendReceiveString.pde

@@ -15,7 +15,7 @@
 
 #include <SPI.h>         // needed for Arduino versions later than 0018
 #include <Ethernet.h>
-#include <Udp.h>         // UDP library from: bjoern@cs.stanford.edu 12/30/2008
+#include <EthernetUdp.h>         // UDP library from: bjoern@cs.stanford.edu 12/30/2008
 
 
 // Enter a MAC address and IP address for your controller below.
@@ -30,8 +30,8 @@ unsigned int localPort = 8888;      // local port to listen on
 char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,
 char  ReplyBuffer[] = "acknowledged";       // a string to send back
 
-// A UDP instance to let us send and receive packets over UDP
-UDP Udp;
+// An EthernetUDP instance to let us send and receive packets over UDP
+EthernetUDP Udp;
 
 void setup() {
   // start the Ethernet and UDP:

libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.pde

@@ -18,7 +18,7 @@
 
 #include <SPI.h>         
 #include <Ethernet.h>
-#include <Udp.h>
+#include <EthernetUdp.h>
 
 // Enter a MAC address for your controller below.
 // Newer Ethernet shields have a MAC address printed on a sticker on the shield
@@ -34,7 +34,7 @@ const int NTP_PACKET_SIZE= 48; // NTP time stamp is in the first 48 bytes of the
 byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets 
 
 // A UDP instance to let us send and receive packets over UDP
-UDP Udp;
+EthernetUDP Udp;
 
 void setup() 
 {