80 lines
2.9 KiB
C
80 lines
2.9 KiB
C
/*
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* Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield.
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* This version only offers minimal wrapping of socket.c/socket.h
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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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#define UDP_TX_PACKET_MAX_SIZE 24
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struct _udp_t {
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unsigned port; // local port to listen on
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unsigned sock; // socket ID for Wiz5100
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};
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typedef struct _udp_t udp_t;
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/*
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* Initialize, start listening on specified port.
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* Returns 1 if successful, 0 if there are no sockets available to use.
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*/
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int udp_init (udp_t *u, unsigned port);
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/*
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* Has data been received?
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*/
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unsigned udp_available (udp_t *u);
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/*
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* Finish with the UDP socket.
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*/
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void udp_stop (udp_t *u);
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/*
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* Send a packet to specified peer.
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*/
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uint16_t udp_send_packet (udp_t *u, const uint8_t *data, unsigned len,
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uint8_t *ip, unsigned port);
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/*
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* Send a zero-terminated string to specified peer.
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*/
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uint16_t udp_send_string (udp_t *u, const char *data,
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uint8_t *ip, unsigned port);
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/*
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* Read a received packet, also return sender's ip and port.
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*/
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int udp_read_packet (udp_t *u, uint8_t *buf, unsigned len, uint8_t *ip, unsigned *port);
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#endif
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