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