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/*
* locator.c
*
* Device Locator server using UDP
*
*/
/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/
/* Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
* ALL RIGHTS RESERVED
*/
#include "locator.h"
#include "lwiplib.h"
/******************************************************************************
** INTERNAL MACRO DEFINITIONS
*******************************************************************************/
#define TAG_CMD (0xff)
#define TAG_STATUS (0xfe)
#define CMD_DISCOVER_TARGET (0x02)
/******************************************************************************
** INTERNAL VARIABLE DEFINITIONS
*******************************************************************************/
/*
** An array that contains the device locator response data. The format of the
** data is as follows:
**
** Byte Description
** -------- ------------------------
** 0 TAG_STATUS
** 1 packet length
** 2 CMD_DISCOVER_TARGET
** 3 board type
** 4 board ID
** 5..8 client IP address
** 9..14 MAC address
** 15..18 firmware version
** 19..82 application title
** 83 checksum
*/
static unsigned char locatorData[84];
/******************************************************************************
** INTERNAL FUNCTION PROTOTYPES
*******************************************************************************/
static void LocatorReceive(void *arg, struct udp_pcb *pcb, struct pbuf *p,
ip_addr_t *addr, u16_t port);
/******************************************************************************
** FUNCTION DEFINITIONS
*******************************************************************************/
/*
** This function is called by the lwIP TCP/IP stack when it receives a UDP
** packet from the discovery port. It produces the response packet, which is
** sent back to the querying client.
*/
static void LocatorReceive(void *arg, struct udp_pcb *pcb, struct pbuf *p,
ip_addr_t *addr, u16_t port)
{
unsigned char *pucData;
unsigned long ulIdx;
/* Validate the contents of the datagram.*/
pucData = p->payload;
if((p->len != 4) || (pucData[0] != TAG_CMD) || (pucData[1] != 4) ||
(pucData[2] != CMD_DISCOVER_TARGET) ||
(pucData[3] != ((0 - TAG_CMD - 4 - CMD_DISCOVER_TARGET) & 0xff)))
{
pbuf_free(p);
return;
}
pbuf_free(p);
p = pbuf_alloc(PBUF_TRANSPORT, sizeof(locatorData), PBUF_RAM);
if(p == NULL)
{
return;
}
/* Calcuate and fill in the checksum on the response packet.*/
for(ulIdx = 0, locatorData[sizeof(locatorData) - 1] = 0;
ulIdx < (sizeof(locatorData) - 1); ulIdx++)
{
locatorData[sizeof(locatorData) - 1] -=
locatorData[ulIdx];
}
/* Copy the response packet data into the pbuf. */
pucData = p->payload;
for(ulIdx = 0; ulIdx < sizeof(locatorData); ulIdx++)
{
pucData[ulIdx] = locatorData[ulIdx];
}
/* Send the response.*/
udp_sendto(pcb, p, addr, port);
pbuf_free(p);
}
/*
** Initializes the locator service. Prepares the locator service to
** handle device discovery requests. .
*/
void LocatorConfig(unsigned char *macArray, const char *appTitle)
{
unsigned int idx;
void *pcb;
/* Clear out the response data.*/
for(idx = 0; idx < 84; idx++)
{
locatorData[idx] = 0;
}
/* Fill in the header for the response data.*/
locatorData[0] = TAG_STATUS;
locatorData[1] = sizeof(locatorData);
locatorData[2] = CMD_DISCOVER_TARGET;
/* Fill in the MAC address for the response data. */
locatorData[9] = macArray[0];
locatorData[10] = macArray[1];
locatorData[11] = macArray[2];
locatorData[12] = macArray[3];
locatorData[13] = macArray[4];
locatorData[14] = macArray[5];
/* Create a new UDP port for listening to device locator requests.*/
pcb = udp_new();
udp_recv(pcb, (udp_recv_fn) LocatorReceive, NULL);
udp_bind(pcb, IP_ADDR_ANY, 23);
udp_connect(pcb, IP_ADDR_ANY, 23);
/* Copy the application title string into the response data. */
for(idx = 0; (idx < 64) && *appTitle; idx++)
{
locatorData[idx + 19] = *appTitle++;
}
/* Zero-fill the remainder of the space in the response data (if any).*/
for(; idx < 64; idx++)
{
locatorData[idx + 19] = 0;
}
}
/***************************** End Of File ***********************************/
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