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         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 106
 107         RFCOMM_SendFrame(FrameHeader->Address, RFCOMM_Frame_UA, 0, NULL, Channel);
 108 }
 109
 110 static void RFCOMM_ProcessUA(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 111 {
 112         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 113
 114         BT_RFCOMM_DEBUG(1, "<< UA Received");
 115         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 116 }
 117
 118 static void RFCOMM_ProcessDM(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 119 {
 120         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 121
 122         BT_RFCOMM_DEBUG(1, "<< DM Received");
 123         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 124 }
 125
 126 static void RFCOMM_ProcessDISC(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 127 {
 128         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 129
 130         BT_RFCOMM_DEBUG(1, "<< DISC Received");
 131         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 132 }
 133
 134 static void RFCOMM_ProcessUIH(const RFCOMM_Header_t* const FrameHeader, Bluetooth_Channel_t* const Channel)
 135 {
 136         const uint8_t* CurrBufferPos = ((const uint8_t*)FrameHeader + sizeof(RFCOMM_Header_t));
 137
 138         BT_RFCOMM_DEBUG(1, "<< UIH Received");
 139         BT_RFCOMM_DEBUG(2, "-- Address 0x%02X", FrameHeader->Address);
 140 }
 141
 142 static void RFCOMM_SendFrame(const uint8_t Address, const uint8_t Type, const uint16_t DataLen, const uint8_t* Data,
 143                              Bluetooth_Channel_t* const Channel)
 144 {
 145         struct
 146         {
 147                 RFCOMM_Header_t FrameHeader;
 148                 uint8_t         Size[1 + (DataLen >= 128)];
 149                 uint8_t         Data[DataLen];
 150                 uint8_t         FCS;
 151         } ResponsePacket;
 152
 153         /* Set the frame header values to the specified address and frame type */
 154         ResponsePacket.FrameHeader.Address = Address;
 155         ResponsePacket.FrameHeader.Control = Type;
 156
 157         /* Set the lower 7 bits of the packet length */
 158         ResponsePacket.Size[0] = (DataLen << 1);
 159
 160         /* Terminate the size field if size is 7 bits or lower, otherwise set the upper 8 bits of the length */
 161         if (DataLen < 128)
 162           ResponsePacket.Size[0] |= 0x01;
 163         else
 164           ResponsePacket.Size[1]  = (DataLen >> 7);
 165
 166         /* Copy over the packet data from the source buffer to the response packet buffer */
 167         memcpy(ResponsePacket.Data, Data, DataLen);
 168
 169         /* Calculate the frame checksum from all fields except the FCS field itself */
 170         ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, sizeof(ResponsePacket) - sizeof(ResponsePacket.FCS));
 171
 172         /* Send the completed response packet to the sender */
 173         Bluetooth_SendPacket(&ResponsePacket, sizeof(ResponsePacket), Channel);
 174 }
 175
 176 static uint8_t RFCOMM_GetFCSValue(const void* FrameStart, uint16_t Length)
 177 {
 178         const uint8_t* CurrPos = FrameStart;
 179         uint8_t        FCS     = 0xFF;
 180
 181         while (Length--)
 182           FCS = pgm_read_byte(CRC8_Table[FCS ^ *(CurrPos++)]);
 183
 184         return ~FCS;
 185 }
 186
 187 static uint16_t RFCOMM_GetFrameDataLength(const uint8_t** BufferPos)
 188 {
 189         uint8_t FirstOctet  = *((*BufferPos)++);
 190         uint8_t SecondOctet = 0;
 191
 192         if (!(FirstOctet & 0x01))
 193           SecondOctet = *((*BufferPos)++);
 194
 195         return (((uint16_t)SecondOctet << 7) | (FirstOctet >> 1));
 196 }
 197