Fix for issue 439. UDP API changed to derive from Stream. The old sendPacket and readPacket calls have been removed, and replaced with Stream-derived alternatives which provide more commonality with other communications classes and to allow both buffered and full-packet-at-a-time uses. Also includes the introduction of an IPAddress class to make passing them around easier (and require fewer pointers to be exposed)

Author: amcewen

libraries/Ethernet/IPAddress.cpp

@@ -0,0 +1,39 @@
+
+#include <WProgram.h>
+#include <IPAddress.h>
+
+IPAddress::IPAddress()
+{
+    memset(_address, 0, sizeof(_address));
+}
+
+IPAddress::IPAddress(uint8_t first_octet, uint8_t second_octet, uint8_t third_octet, uint8_t fourth_octet)
+{
+    _address[0] = first_octet;
+    _address[1] = second_octet;
+    _address[2] = third_octet;
+    _address[3] = fourth_octet;
+}
+
+IPAddress::IPAddress(uint32_t address)
+{
+    memcpy(_address, &address, sizeof(_address));
+}
+
+IPAddress::IPAddress(const uint8_t *address)
+{
+    memcpy(_address, address, sizeof(_address));
+}
+
+IPAddress& IPAddress::operator=(const uint8_t *address)
+{
+    memcpy(_address, address, sizeof(_address));
+    return *this;
+}
+
+IPAddress& IPAddress::operator=(uint32_t address)
+{
+    memcpy(_address, (const uint8_t *)&address, sizeof(_address));
+    return *this;
+}
+

libraries/Ethernet/IPAddress.h

@@ -0,0 +1,55 @@
+/*
+ *
+ * MIT License:
+ * Copyright (c) 2011 Adrian McEwen
+ * 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.
+ *
+ * adrianm@mcqn.com 1/1/2011
+ */
+
+#ifndef IPAddress_h
+#define IPAddress_h
+
+// A class to make it easier to handle and pass around IP addresses
+
+class IPAddress {
+private:
+    uint8_t _address[4];  // IPv4 address
+
+public:
+    // Constructors
+    IPAddress();
+    IPAddress(uint8_t first_octet, uint8_t second_octet, uint8_t third_octet, uint8_t fourth_octet);
+    IPAddress(uint32_t address);
+    IPAddress(const uint8_t *address);
+
+    // Overloaded cast operator to allow IPAddress objects to be used where a pointer
+    // to a four-byte uint8_t array is expected
+    operator uint8_t*() { return _address; };
+
+    // Overloaded index operator to allow getting and setting individual octets of the address
+    uint8_t operator[](int index) const { return _address[index]; };
+    uint8_t& operator[](int index) { return _address[index]; };
+
+    // Overloaded copy operators to allow initialisation of IPAddress objects from other types
+    IPAddress& operator=(const uint8_t *address);
+    IPAddress& operator=(uint32_t address);
+};
+
+#endif

libraries/Ethernet/Udp.cpp

@@ -56,106 +56,111 @@ uint8_t UDP::begin(uint16_t port) {
   return 1;
 }
 
-/* Send packet contained in buf of length len to peer at specified ip, and port */
-/* Use this function to transmit binary data that might contain 0x00 bytes*/
-/* This function returns sent data size for success else -1. */
-uint16_t UDP::sendPacket(uint8_t * buf, uint16_t len,  uint8_t * ip, uint16_t port){
-  return sendto(_sock,(const uint8_t *)buf,len,ip,port);
-}
-
-/* Send  zero-terminated string str as packet to peer at specified ip, and port */
-/* This function returns sent data size for success else -1. */
-uint16_t UDP::sendPacket(const char str[], uint8_t * ip, uint16_t port){	
-  // compute strlen
-  const char *s;
-  for(s = str; *s; ++s);
-  uint16_t len = (s-str);
-  // send packet
-  return sendto(_sock,(const uint8_t *)str,len,ip,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() {
   return W5100.getRXReceivedSize(_sock);
 }
 
+/* Release any resources being used by this UDP instance */
+void UDP::stop()
+{
+  if (_sock == MAX_SOCK_NUM)
+    return;
 
-/* Read a received packet into buffer buf (which is of maximum length len); */
-/* store calling ip and port as well. Call available() to make sure data is ready first. */
-/* NOTE: I don't believe len is ever checked in implementation of recvfrom(),*/
-/*       so it's easy to overflow buffer. so we check and truncate. */
-/* returns number of bytes read, or negative number of bytes we would have needed if we truncated */
-int UDP::readPacket(uint8_t * buf, uint16_t bufLen, uint8_t *ip, uint16_t *port) {
-  int packetLen = available()-8; //skip UDP header;
-  if(packetLen < 0 ) return 0; // no real data here	
-  if(packetLen > (int)bufLen) {
-    //packet is too large - truncate
-    //HACK - hand-parse the UDP packet using TCP recv method
-    uint8_t tmpBuf[8];
-    int i;
-    //read 8 header bytes and get IP and port from it
-    recv(_sock,tmpBuf,8);
-    ip[0] = tmpBuf[0];
-    ip[1] = tmpBuf[1];
-    ip[2] = tmpBuf[2];
-    ip[3] = tmpBuf[3];
-    *port = tmpBuf[4];
-    *port = (*port << 8) + tmpBuf[5];
-
-    //now copy first (bufLen) bytes into buf		
-    for(i=0;i<(int)bufLen;i++) {
-      recv(_sock,tmpBuf,1);
-      buf[i]=tmpBuf[0];
-    }
+  close(_sock);
 
-    //and just read the rest byte by byte and throw it away
-    while(available()) {
-      recv(_sock,tmpBuf,1);
-    }
+  EthernetClass::_server_port[_sock] = 0;
+  _sock = MAX_SOCK_NUM;
+}
 
-    return (-1*packetLen);
+int UDP::beginPacket(IPAddress ip, uint16_t port)
+{
+  _offset = 0;
+  return startUDP(_sock, ip, port);
+}
 
-    //ALTERNATIVE: requires stdlib - takes a bunch of space
-    /*//create new buffer and read everything into it
-     		uint8_t * tmpBuf = (uint8_t *)malloc(packetLen);
-     		recvfrom(_sock,tmpBuf,packetLen,ip,port);
-     		if(!tmpBuf) return 0; //couldn't allocate
-     		// copy first bufLen bytes
-     		for(unsigned int i=0; i<bufLen; i++) {
-     			buf[i]=tmpBuf[i];
-     		}
-     		//free temp buffer
-     		free(tmpBuf);
-     		*/
+int UDP::endPacket()
+{
+  return sendUDP(_sock);
+}
 
+void UDP::write(uint8_t byte)
+{
+  write(&byte, 1);
+}
 
-  } 
-  return recvfrom(_sock,buf,bufLen,ip,port);
+void UDP::write(const char *str)
+{
+  size_t len = strlen(str);
+  write((const uint8_t *)str, len);
 }
 
-/* Read a received packet, throw away peer's ip and port.  See note above. */
-int UDP::readPacket(uint8_t * buf, uint16_t len) {
-  uint8_t ip[4];
-  uint16_t port[1];
-  return recvfrom(_sock,buf,len,ip,port);
+void UDP::write(const uint8_t *buffer, size_t size)
+{
+  uint16_t bytes_written = bufferData(_sock, _offset, buffer, size);
+  _offset += bytes_written;
 }
 
-int UDP::readPacket(char * buf, uint16_t bufLen, uint8_t *ip, uint16_t &port) {
-uint16_t myPort;
-uint16_t ret = readPacket( (byte*)buf, bufLen, ip, &myPort);
-port = myPort;
-return ret;
+int UDP::parsePacket()
+{
+  //HACK - hand-parse the UDP packet using TCP recv method
+  uint8_t tmpBuf[8];
+  int ret =0;	
+  //read 8 header bytes and get IP and port from it
+  ret = recv(_sock,tmpBuf,8);
+  if (ret > 0)
+  {
+    _remoteIP = tmpBuf;
+    _remotePort = tmpBuf[4];
+    _remotePort = (_remotePort << 8) + tmpBuf[5];
+    // When we get here, any remaining bytes are the data
+    ret = available();
+  }
+  return ret;
 }
 
-/* Release any resources being used by this UDP instance */
-void UDP::stop()
+int UDP::read()
 {
-  if (_sock == MAX_SOCK_NUM)
-    return;
+  uint8_t byte;
+  if (recv(_sock, &byte, 1) > 0)
+  {
+    // We read things without any problems
+    return byte;
+  }
+  // If we get here, there's no data available
+  return -1;
+}
 
-  close(_sock);
+int UDP::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
+     at a time.
+  int i;
+  for(i=0;i<(int)bufLen;i++) {
+    recv(_sock,tmpBuf,1);
+    buf[i]=tmpBuf[0];
+  }
+  */
+  return recv(_sock, buffer, len);
+}
 
-  EthernetClass::_server_port[_sock] = 0;
-  _sock = MAX_SOCK_NUM;
+int UDP::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);
+  return b;
+}
+
+void UDP::flush()
+{
+  while (available())
+  {
+    read();
+  }
 }
 

libraries/Ethernet/Udp.h

@@ -37,28 +37,57 @@
 #ifndef udp_h
 #define udp_h
 
+#include <Stream.h>
+#include <IPAddress.h>
+
 #define UDP_TX_PACKET_MAX_SIZE 24
 
-class UDP {
+class UDP : public Stream {
 private:
   uint8_t _sock;  // socket ID for Wiz5100
   uint16_t _port; // local port to listen on
+  IPAddress _remoteIP; // remote IP address for the incoming packet whilst it's being processed
+  uint16_t _remotePort; // remote port for the incoming packet whilst it's being processed
+  uint16_t _offset; // offset into the packet being sent
 
 public:
-  UDP();
+  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
-  int available();								// has data been received?
+  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);
+  // Finish off this packet and send it
+  // Returns 1 if the packet was sent successfully, 0 if there was an error
+  int endPacket();
+  // Write a single byte into the packet
+  virtual void write(uint8_t);
+  // Write a string of characters into the packet
+  virtual void write(const char *str);
+  // Write size bytes from buffer into the packet
+  virtual void write(const uint8_t *buffer, size_t size);
 
-  // C-style buffer-oriented functions
-  uint16_t sendPacket(uint8_t *, uint16_t, uint8_t *, uint16_t); //send a packet to specified peer 
-  uint16_t sendPacket(const char[], uint8_t *, uint16_t);  //send a string as a packet to specified peer
-  int readPacket(uint8_t *, uint16_t);		// read a received packet 
-  int readPacket(uint8_t *, uint16_t, uint8_t *, uint16_t *);		// read a received packet, also return sender's ip and port 	
-  // readPacket that fills a character string buffer
-  int readPacket(char *, uint16_t, uint8_t *, uint16_t &);
+  // Start processing the next available incoming packet
+  // Returns the size of the packet in bytes, or 0 if no packets are available
+  int parsePacket();
+  // Number of bytes remaining in the current packet
+  virtual int available();
+  // Read a single byte from the current packet
+  virtual int read();
+  // 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);
+  // Return the next byte from the current packet without moving on to the next byte
+  virtual int peek();
+  virtual void flush();	// Finish reading the current packet
 
-  // Finish with the UDP socket
-  void stop();
+  // Return the IP address of the host who sent the current incoming packet
+  IPAddress remoteIP() { return _remoteIP; };
+  // Return the port of the host who sent the current incoming packet
+  uint16_t remotePort() { return _remotePort; };
 };
 
 #endif