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/*
* Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield.
* This version only offers minimal wrapping of socket.c/socket.h
* Drop Udp.h/.cpp into the Ethernet library directory at hardware/libraries/Ethernet/
*
* MIT License:
* Copyright (c) 2008 Bjoern Hartmann
* 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.
*
* bjoern@cs.stanford.edu 12/30/2008
*/
#include "w5100.h"
#include "socket.h"
#include "Ethernet.h"
#include "Udp.h"
/* Start UDP socket, listening at local port PORT */
void UdpClass::begin(uint16_t port) {
_port = port;
_sock = 0; //TODO: should not be hardcoded
socket(_sock, SnMR::UDP, _port, 0);
}
/* 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 UdpClass::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 UdpClass::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 UdpClass::available() {
return W5100.getRXReceivedSize(_sock);
}
/* 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 UdpClass::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];
}
//and just read the rest byte by byte and throw it away
while(available()) {
recv(_sock,tmpBuf,1);
}
return (-1*packetLen);
//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);
*/
}
return recvfrom(_sock,buf,bufLen,ip,port);
}
/* Read a received packet, throw away peer's ip and port. See note above. */
int UdpClass::readPacket(uint8_t * buf, uint16_t len) {
uint8_t ip[4];
uint16_t port[1];
return recvfrom(_sock,buf,len,ip,port);
}
int UdpClass::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;
}
/* Create one global object */
UdpClass Udp;
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