Demos/Host/Incomplete/BluetoothHost/Lib/RFCOMM.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  RFCOMM layer module. This module manages the RFCOMM layer of the
  34  *  stack, providing virtual serial port channels on top of the lower
  35  *  L2CAP layer.
  36  */
  37
  38 #define  INCLUDE_FROM_RFCOMM_C
  39 #include "RFCOMM.h"
  40
  41 /** 8-Bit CRC table used by the FCS field of each RFCOMM encoded frame, sourced from the ETSI TS 101 369 V7.2.0
  42  *  specification document, upon which the RFCOMM specification is based.
  43  */
  44 const uint8_t CRC8_Table[256] PROGMEM =
  45         {
  46                 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
  47                 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
  48                 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
  49                 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
  50                 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
  51                 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
  52                 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
  53                 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
  54                 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
  55                 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
  56                 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
  57                 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
  58                 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
  59                 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
  60                 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
  61                 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
  62         };
  63
  64 /** Initializes the RFCOMM service, ready for new connections from a SDP client. */
  65 void RFCOMM_Initialize(void)
  66 {
  67         /* Not currently used */
  68 }
  69
  70 void RFCOMM_ProcessPacket(void* Data, Bluetooth_Channel_t* const Channel)
  71 {
  72         const RFCOMM_Header_t* FrameHeader = (const RFCOMM_Header_t*)Data;
  73
  74         /* Decode the RFCOMM frame type from the header */
  75         switch (FrameHeader->Control & ~FRAME_POLL_FINAL)
  76         {
  77                 case RFCOMM_Frame_DM:
  78                         RFCOMM_ProcessDM(FrameHeader, Channel);
  79                         break;
  80                 case RFCOMM_Frame_DISC:
  81                         RFCOMM_ProcessDISC(FrameHeader, Channel);
  82                         break;
  83                 case RFCOMM_Frame_SABM:
  84                         RFCOMM_ProcessSABM(FrameHeader, Channel);
  85                         break;
  86                 case RFCOMM_Frame_UA:
  87                         RFCOMM_ProcessUA(FrameHeader, Channel);
  88                         break;
  89                 case RFCOMM_Frame_UIH:
  90                         RFCOMM_ProcessUIH(FrameHeader, Channel);
  91                         break;
  92                 default:
  93                         BT_RFCOMM_DEBUG(1, "<< Unknown Frame Type");
  94                         break;
  95         }
  96 }
  97
  98 static void RFCOMM_ProcessDM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
  99 {
 100         BT_RFCOMM_DEBUG(1, "<< DM Received");
 101         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 102 }
 103
 104 static void RFCOMM_ProcessDISC(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 105 {
 106         BT_RFCOMM_DEBUG(1, "<< DISC Received");
 107         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 108
 109         // TODO: Close down connection
 110
 111         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 112         RFCOMM_SendFrame(FrameHeader->Address.DLCI, true, (RFCOMM_Frame_UA | FRAME_POLL_FINAL), 0, NULL, Channel);
 113 }
 114
 115 static void RFCOMM_ProcessSABM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 116 {
 117         BT_RFCOMM_DEBUG(1, "<< SABM Received");
 118         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 119
 120         // TODO: Reset channel send/receive state
 121
 122         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 123         RFCOMM_SendFrame(FrameHeader->Address.DLCI, true, (RFCOMM_Frame_UA | FRAME_POLL_FINAL), 0, NULL, Channel);
 124 }
 125
 126 static void RFCOMM_ProcessUA(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 127 {
 128         BT_RFCOMM_DEBUG(1, "<< UA Received");
 129         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 130 }
 131
 132 static void RFCOMM_ProcessUIH(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 133 {
 134         BT_RFCOMM_DEBUG(1, "<< UIH Received");
 135         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 136
 137         uint8_t* FrameData    = (uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t);
 138         uint16_t FrameDataLen = RFCOMM_GetFrameDataLength(FrameData);
 139         FrameData += (FrameDataLen < 128) ? 1 : 2;
 140
 141         BT_RFCOMM_DEBUG(2, "-- Length 0x%02X", FrameDataLen);
 142
 143         if (FrameHeader->Address.DLCI == RFCOMM_CONTROL_DLCI)
 144         {
 145                 // TODO: Process control command
 146         }
 147 }
 148
 149 static void RFCOMM_SendFrame(const uint8_t DLCI, const bool CommandResponse, const uint8_t Control, const uint16_t DataLen, const uint8_t* Data,
 150                              Bluetooth_Channel_t* const Channel)
 151 {
 152         struct
 153         {
 154                 RFCOMM_Header_t FrameHeader;
 155                 uint8_t         Size[(DataLen < 128) ? 1 : 2];
 156                 uint8_t         Data[DataLen];
 157                 uint8_t         FCS;
 158         } ResponsePacket;
 159
 160         /* Set the frame header values to the specified address and frame type */
 161         ResponsePacket.FrameHeader.Control = Control;
 162         ResponsePacket.FrameHeader.Address = (RFCOMM_Address_t)
 163                 {
 164                         .EA   = true,
 165                         .CR   = CommandResponse,
 166                         .DLCI = DLCI,
 167                 };
 168
 169         /* Set the lower 7 bits of the packet length */
 170         ResponsePacket.Size[0] = (DataLen << 1);
 171
 172         /* Terminate the size field if size is 7 bits or lower, otherwise set the upper 8 bits of the length */
 173         if (DataLen < 128)
 174           ResponsePacket.Size[0] |= 0x01;
 175         else
 176           ResponsePacket.Size[1]  = (DataLen >> 7);
 177
 178         /* Copy over the packet data from the source buffer to the response packet buffer */
 179         memcpy(ResponsePacket.Data, Data, DataLen);
 180
 181         /* Determine the length of the frame which is to be used to calculate the CRC value */
 182         uint8_t CRCLength = sizeof(ResponsePacket.FrameHeader);
 183
 184         if ((Control & ~FRAME_POLL_FINAL) != RFCOMM_Frame_UIH)
 185           CRCLength += sizeof(ResponsePacket.Size);
 186
 187         /* Calculate the frame checksum from the appropriate fields */
 188         ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, CRCLength);
 189
 190         /* Send the completed response packet to the sender */
 191         Bluetooth_SendPacket(&ResponsePacket, sizeof(ResponsePacket), Channel);
 192 }
 193
 194 static uint8_t RFCOMM_GetFCSValue(const void* FrameStart, uint8_t Length)
 195 {
 196         const uint8_t* CurrPos = FrameStart;
 197         uint8_t        FCS     = 0xFF;
 198
 199         for (uint8_t i = 0; i < Length; i++)
 200           FCS = pgm_read_byte(&CRC8_Table[FCS ^ *(CurrPos++)]);
 201
 202         return ~FCS;
 203 }
 204
 205 static uint16_t RFCOMM_GetFrameDataLength(const uint8_t* const BufferPos)
 206 {
 207         uint8_t FirstOctet  = BufferPos[0];
 208         uint8_t SecondOctet = 0;
 209
 210         if (!(FirstOctet & 0x01))
 211           SecondOctet = BufferPos[1];
 212
 213         return (((uint16_t)SecondOctet << 7) | FirstOctet >> 1);
 214 }
 215