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_SABM:
  78                         RFCOMM_ProcessSABM(FrameHeader, Channel);
  79                         break;
  80                 case RFCOMM_Frame_UA:
  81                         RFCOMM_ProcessUA(FrameHeader, Channel);
  82                         break;
  83                 case RFCOMM_Frame_DM:
  84                         RFCOMM_ProcessDM(FrameHeader, Channel);
  85                         break;
  86                 case RFCOMM_Frame_DISC:
  87                         RFCOMM_ProcessDISC(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_ProcessSABM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
  99 {
 100         BT_RFCOMM_DEBUG(1, "<< SABM Received");
 101         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameHeader->Address.DLCI);
 102
 103         // TODO: Reset channel send/receive state here
 104
 105         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 106         RFCOMM_SendFrame(FrameHeader->Address.DLCI, true, (RFCOMM_Frame_UA | FRAME_POLL_FINAL), 0, NULL, Channel);
 107 }
 108
 109 static void RFCOMM_ProcessUA(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 110 {
 111         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 112
 113         BT_RFCOMM_DEBUG(1, "<< UA Received");
 114         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 115 }
 116
 117 static void RFCOMM_ProcessDM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 118 {
 119         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 120
 121         BT_RFCOMM_DEBUG(1, "<< DM Received");
 122         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 123 }
 124
 125 static void RFCOMM_ProcessDISC(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 126 {
 127         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 128
 129         BT_RFCOMM_DEBUG(1, "<< DISC Received");
 130         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 131 }
 132
 133 static void RFCOMM_ProcessUIH(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 134 {
 135         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 136
 137         BT_RFCOMM_DEBUG(1, "<< UIH Received");
 138         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 139 }
 140
 141 static void RFCOMM_SendFrame(const uint8_t DLCI, const bool CommandResponse, const uint8_t Control, const uint16_t DataLen, const uint8_t* Data,
 142                              Bluetooth_Channel_t* const Channel)
 143 {
 144         struct
 145         {
 146                 RFCOMM_Header_t FrameHeader;
 147                 uint8_t         Size[(DataLen < 128) ? 1 : 2];
 148                 uint8_t         Data[DataLen];
 149                 uint8_t         FCS;
 150         } ResponsePacket;
 151
 152         /* Set the frame header values to the specified address and frame type */
 153         ResponsePacket.FrameHeader.Control = Control;
 154         ResponsePacket.FrameHeader.Address = (RFCOMM_Address_t)
 155                 {
 156                         .EA   = true,
 157                         .CR   = CommandResponse,
 158                         .DLCI = DLCI,
 159                 };
 160
 161         /* Set the lower 7 bits of the packet length */
 162         ResponsePacket.Size[0] = (DataLen << 1);
 163
 164         /* Terminate the size field if size is 7 bits or lower, otherwise set the upper 8 bits of the length */
 165         if (DataLen < 128)
 166           ResponsePacket.Size[0] |= 0x01;
 167         else
 168           ResponsePacket.Size[1]  = (DataLen >> 7);
 169
 170         /* Copy over the packet data from the source buffer to the response packet buffer */
 171         memcpy(ResponsePacket.Data, Data, DataLen);
 172
 173         /* Calculate the frame checksum from the appropriate fields */
 174         if ((Control & ~FRAME_POLL_FINAL) == RFCOMM_Frame_UIH)
 175           ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, sizeof(ResponsePacket.FrameHeader));
 176         else
 177           ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, sizeof(ResponsePacket.FrameHeader) + sizeof(ResponsePacket.Size));
 178
 179         /* Send the completed response packet to the sender */
 180         Bluetooth_SendPacket(&ResponsePacket, sizeof(ResponsePacket), Channel);
 181 }
 182
 183 static uint8_t RFCOMM_GetFCSValue(const void* FrameStart, uint16_t Length)
 184 {
 185         const uint8_t* CurrPos = FrameStart;
 186         uint8_t        FCS     = 0xFF;
 187
 188         while (Length--)
 189         {
 190                 FCS = pgm_read_byte(&CRC8_Table[FCS ^ *CurrPos]);
 191                 CurrPos++;
 192         }
 193
 194         return (0xFF - FCS);
 195 }
 196
 197 static uint16_t RFCOMM_GetFrameDataLength(const uint8_t** BufferPos)
 198 {
 199         uint8_t FirstOctet  = *((*BufferPos)++);
 200         uint8_t SecondOctet = 0;
 201
 202         if (!(FirstOctet & 0x01))
 203           SecondOctet = *((*BufferPos)++);
 204
 205         return (((uint16_t)SecondOctet << 7) | (FirstOctet >> 1));
 206 }
 207