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, "-- Address 0x%02X", FrameHeader->Address);
 102
 103         // TODO: Reset channel send/receive state here
 104
 105         struct
 106         {
 107                 RFCOMM_Header_t FrameHeader;
 108                 uint8_t         FrameLength;
 109                 uint8_t         FCS;
 110         } ResponsePacket;
 111
 112         /* Copy over the same frame header as the sent packet to copy the logical RFCOMM channel address */
 113         ResponsePacket.FrameHeader.Address              = FrameHeader->Address;
 114
 115         /* Set the frame type to an Unnumbered Acknowledgement to acknowledge the SABM request */
 116         ResponsePacket.FrameHeader.Control = RFCOMM_Frame_UA;
 117
 118         /* Set the length to 0 (LSB indicates end of 8-bit length field) */
 119         ResponsePacket.FrameLength = 0x01;
 120
 121         /* Calculate the frame checksum from all fields except the FCS field itself */
 122         ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, sizeof(ResponsePacket) - sizeof(ResponsePacket.FCS));
 123
 124         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 125
 126         /* Send the completed response packet to the sender */
 127         Bluetooth_SendPacket(&ResponsePacket, sizeof(ResponsePacket), Channel);
 128 }
 129
 130 static void RFCOMM_ProcessUA(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 131 {
 132         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 133
 134         BT_RFCOMM_DEBUG(1, "<< UA Received");
 135         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 136 }
 137
 138 static void RFCOMM_ProcessDM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 139 {
 140         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 141
 142         BT_RFCOMM_DEBUG(1, "<< DM Received");
 143         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 144 }
 145
 146 static void RFCOMM_ProcessDISC(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 147 {
 148         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 149
 150         BT_RFCOMM_DEBUG(1, "<< DISC Received");
 151         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 152 }
 153
 154 static void RFCOMM_ProcessUIH(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 155 {
 156         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 157
 158         BT_RFCOMM_DEBUG(1, "<< UIH Received");
 159         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 160 }
 161
 162 static uint8_t RFCOMM_GetFCSValue(const void* FrameStart, uint16_t Length)
 163 {
 164         const uint8_t* CurrPos = FrameStart;
 165         uint8_t        FCS     = 0xFF;
 166
 167         while (Length--)
 168           FCS = pgm_read_byte(CRC8_Table[FCS ^ *(CurrPos++)]);
 169
 170         return ~FCS;
 171 }
 172
 173 static uint16_t RFCOMM_GetFrameDataLength(const uint8_t** BufferPos)
 174 {
 175         uint8_t FirstOctet  = *((*BufferPos)++);
 176         uint8_t SecondOctet = 0;
 177
 178         if (!(FirstOctet & 0x01))
 179           SecondOctet = *((*BufferPos)++);
 180
 181         return (((uint16_t)SecondOctet << 7) | (FirstOctet >> 1));
 182 }
 183