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