1 /* 2 * Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield. 3 * This version only offers minimal wrapping of socket.c/socket.h 4 * Drop Udp.h/.cpp into the Ethernet library directory at hardware/libraries/Ethernet/ 5 * 6 * NOTE: UDP is fast, but has some important limitations (thanks to Warren Gray for mentioning these) 7 * 1) UDP does not guarantee the order in which assembled UDP packets are received. This 8 * might not happen often in practice, but in larger network topologies, a UDP 9 * packet can be received out of sequence. 10 * 2) UDP does not guard against lost packets - so packets *can* disappear without the sender being 11 * aware of it. Again, this may not be a concern in practice on small local networks. 12 * For more information, see http://www.cafeaulait.org/course/week12/35.html 13 * 14 * MIT License: 15 * Copyright (c) 2008 Bjoern Hartmann 16 * Permission is hereby granted, free of charge, to any person obtaining a copy 17 * of this software and associated documentation files (the "Software"), to deal 18 * in the Software without restriction, including without limitation the rights 19 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 20 * copies of the Software, and to permit persons to whom the Software is 21 * furnished to do so, subject to the following conditions: 22 * 23 * The above copyright notice and this permission notice shall be included in 24 * all copies or substantial portions of the Software. 25 * 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 31 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 32 * THE SOFTWARE. 33 * 34 * bjoern@cs.stanford.edu 12/30/2008 35 */ 36 37 #ifndef ethernetudp_h 38 #define ethernetudp_h 39 40 #include <Udp.h> 41 42 #define UDP_TX_PACKET_MAX_SIZE 24 43 44 class EthernetUDP : public UDP { 45 private: 46 uint16_t _port; // local port to listen on 47 IPAddress _remoteIP; // remote IP address for the incoming packet whilst it's being processed 48 uint16_t _remotePort; // remote port for the incoming packet whilst it's being processed 49 uint16_t _offset; // offset into the packet being sent 50 51 protected: 52 uint8_t _sock; // socket ID for Wiz5100 53 uint16_t _remaining; // remaining bytes of incoming packet yet to be processed 54 55 public: 56 EthernetUDP(); // Constructor 57 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 58 virtual uint8_t beginMulticast(IPAddress, uint16_t); // initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use 59 virtual void stop(); // Finish with the UDP socket 60 61 // Sending UDP packets 62 63 // Start building up a packet to send to the remote host specific in ip and port 64 // Returns 1 if successful, 0 if there was a problem with the supplied IP address or port 65 virtual int beginPacket(IPAddress ip, uint16_t port); 66 // Start building up a packet to send to the remote host specific in host and port 67 // Returns 1 if successful, 0 if there was a problem resolving the hostname or port 68 virtual int beginPacket(const char *host, uint16_t port); 69 // Finish off this packet and send it 70 // Returns 1 if the packet was sent successfully, 0 if there was an error 71 virtual int endPacket(); 72 // Write a single byte into the packet 73 virtual size_t write(uint8_t); 74 // Write size bytes from buffer into the packet 75 virtual size_t write(const uint8_t *buffer, size_t size); 76 77 using Print::write; 78 79 // Start processing the next available incoming packet 80 // Returns the size of the packet in bytes, or 0 if no packets are available 81 virtual int parsePacket(); 82 // Number of bytes remaining in the current packet 83 virtual int available(); 84 // Read a single byte from the current packet 85 virtual int read(); 86 // Read up to len bytes from the current packet and place them into buffer 87 // Returns the number of bytes read, or 0 if none are available 88 virtual int read(unsigned char* buffer, size_t len); 89 // Read up to len characters from the current packet and place them into buffer 90 // Returns the number of characters read, or 0 if none are available read(char * buffer,size_t len)91 virtual int read(char* buffer, size_t len) { return read((unsigned char*)buffer, len); }; 92 // Return the next byte from the current packet without moving on to the next byte 93 virtual int peek(); 94 virtual void flush(); // Finish reading the current packet 95 96 // Return the IP address of the host who sent the current incoming packet remoteIP()97 virtual IPAddress remoteIP() { return _remoteIP; }; 98 // Return the port of the host who sent the current incoming packet remotePort()99 virtual uint16_t remotePort() { return _remotePort; }; 100 }; 101 102 #endif 103