Colony

/**

 * Copyright (c) 2009 Colony Project

 *

 * 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.

 **/

/**

 * @file wireless_send.c

 * @brief Wireless library send functions

 *

 * Implementation of high level wireless communication.

 * This is the send functions portion of the library.

 *

 * @author Colony Project, CMU Robotics Club

 **/

#include "wl_defs.h"

#include "wireless.h"

#include <string.h>

/**

 * Definition for wireless library send packet structure

 * byte 1: length of packet

 * byte 2: frame number

 * byte 3: group code 

 * bytes 4-n: data

 * (byte n+1: num retries - only saved locally in sending buffer)

 *

 * Definition for ack buffer

 * 2 bit system: 0=still sending

 *               1=OK

 *               2=ack failure

 *               3=CCA failure

 **/

/* global variables */

uint8_t nextframe = 1; // number of next frame

uint8_t ack_buf[64]; // ack buffer (holds 255 packet return codes)

uint8_t send_buf[PACKET_BUFFER_SIZE]; // sending buffer for retries

uint8_t send_buf_first = 0; // first byte of data on buffer

uint8_t send_buf_last = 0; // next free byte on buffer

/* private function prototypes */

void setack(uint8_t num,uint8_t val);

// the send functions

/**

 * @addtogroup wireless Wireless

 * @{

 **/

/**

 * The core send function. This will take all possible arguments and send all types of packets.

 * 

 * @param data pointer to the byte array of data to be included in the packet

 * @param length the length of the data array

 * @param group the packet group of the packet

 * @param scope flag for sending global packet or your current PAN

 * @param dest robot ID (for robot to robot packet)

 * @param mode flag for using FAST or RELIABLE sending

 *

 * @return positive packet number for tracking acks, or error code (TBD)

 **/

int16_t wl_send(uint8_t *data, uint8_t length, uint8_t group, uint8_t scope, uint16_t dest, uint8_t mode) {

  uint8_t packet[length+2];

  uint8_t options = XBEE_OPTIONS_NONE;

  int16_t ret_val = (int16_t)nextframe;

  // build packet

  packet[0] = nextframe;

  packet[1] = group;

  memcpy(packet+2,data,length);

  // set scope

  if (scope == GLOBAL)

    options &= XBEE_OPTIONS_BROADCAST_ALL_PANS;

  // set mode

  if (mode == FAST) {

    options &= XBEE_OPTIONS_DISABLE_RESPONSE;

    ret_val = 0;

  } else if (mode != RELIABLE) {

    WL_DEBUG_PRINT("Error - bad mode in core send function\r\n");

    return WL_ERROR_MODE;

  }

  // send the packet

  if (xbee_send_packet(packet,length,dest,options,(uint_8)ret_val) != 0) {

    WL_DEBUG_PRINT("Error sending packet from core send function\r\n");

    return WL_ERROR_SEND;

  }

  // save in ack system

  if (mode == FAST) {

    setack(nextframe,ACK_OK); // assume the send was successful

  } else if (mode == RELIABLE) {

    setack(nextframe,SENDING); // set status to SENDING

    // TODO: save packet on sending buffer

    /* if (buffer full) {

      WL_DEBUG_PRINT("Error: sending buffer full\r\n");

      return WL_ERROR_SENDING_BUFFER_FULL

    } */

  }

  // increment frame number

  nextframe = (nextframe == 0xFF)?1:nextframe+1;

  return ret_val; // return frame number for ack tracking

}

/**

 * Wrapper for core send function that will send a global packet across the current channel.

 *

 * @param data pointer to the byte array of data to be included in the packet

 * @param length the length of the data array

 * @param group the packet group of the packet

 *

 * @return positive packet number for tracking acks, or error code (TBD)

 **/

int16_t wl_send_global(char *data, uint8_t length, uint8_t group) {

  return 0;

}

/**

 * Wrapper for core send function that will send a packet across the current channel on the current pan.

 *

 * @param data pointer to the byte array of data to be included in the packet

 * @param length the length of the data array

 * @param group the packet group of the packet

 *

 * @return positive packet number for tracking acks, or error code (TBD)

 **/

int16_t wl_send_pan(char *data, uint8_t length, uint8_t group) {

  return 0;

}

/**

 * Wrapper for core send function that will send a packet across the current channel to a specific robot. 

 *

 * @param data pointer to the byte array of data to be included in the packet

 * @param length the length of the data array

 * @param group the packet group of the packet 

 * @param dest robot ID (for robot to robot packet)

 * @param mode flag for using FAST or RELIABLE sending

 *

 * @return positive packet number for tracking acks, or error code (TBD)

 **/

int16_t wl_send_robot(char *data, uint8_t length, uint8_t group, uint16_t dest, uint8_t mode) {

  return 0;

}

/**

 * Default (i.e. basic) send wrapper.

 *

 * @param data pointer to the byte array of data to be included in the packet

 * @param length the length of the data array

 *

 * @return positive packet number for tracking acks, or error code (TBD)

 **/

int16_t wl_send_basic(char *data, uint8_t length) {

  return 0;

}

/**

 * acknowledgment error

 * check if any of the packets you have sent have been lost.

 *

 * note that all other error checking will be handled by library, 

 * so your user behavior won't have to worry about it

 *

 * @return the # of packets lost (up to 255)

 **/

uint8_t wl_ack_error(void) {

  uint_8 val=0,i=1;

  while(1) {

    if (ack_buf[i/4]&(0x2<<(i%4)) != 0) // if the ack is in an error state

      val++;

    if (i==255)

      break;

    i++;

  }

  return val;

}

/**

 * acknowledgement error check

 * check if a specific packet has been lost

 * note: buffer will overflow every 255 packets

 * 

 * @param packet packet number

 *

 * @return {SENDING,ACK_OK,ACK_FAILURE,CCA_FAILURE}

 **/

int8_t wl_ack_check(uint8_t packet) {

  if (packet == 0) {

    // no ack information here

    WL_DEBIG_PRINT("packet number cannot be 0\r\n");

    return WL_ERROR_ARGUMENT;

  }

  // check ack

  return ack_buf[packet/4]&(0x3<<(packet%4));

}

/**

 * acknowledgement reset

 * reset the acknowledgement buffer

 **/

void wl_ack_reset(void) {

  memset(ack_buf,0,64);

}

/**@} **/ //end defgroup

// Define all private functions down here

/*

 * sets 2 bits in the ack_buf

 *

 * @param num the ack number

 * @param val {SENDING,ACK_OK,ACK_FAILURE,CCA_FAILURE}

 */

void setack(uint8_t num,uint8_t val) {

  switch(num%4) {

  case 0:

    ack_buf[num/4] &= (0xFC|val);

    break;

  case 1:

    ack_buf[num/4] &= (0xF3|(val<<2));

    break;

  case 2:

    ack_buf[num/4] &= (0xCF|(val<<4));

    break;

  case 3:

    ack_buf[num/4] &= (0x3F|(val<<6));

    break;

  }

}

/* ack handler */

void ackhandle(uint8_t num,uint8_t val) {

  switch(val) {

  case 0:

    // success

    setack(num,ACK_OK); // set status code

    // TODO: remove from sending buffer

    break;

  case 1:

    // no ack

    // TODO: check resend attempts

    setack(num,ACK_FAILURE);

    break;

  case 2:

    // CCA failure

    // TODO: check resend attempts

    setack(num,CCA_FAILURE);

    break;

}