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 /** RFCOMM channel state structure, to retain information about each open channel in the RFCOMM multiplexer. */
  65 RFCOMM_Channel_t RFCOMM_Channels[RFCOMM_MAX_OPEN_CHANNELS];
  66
  67
  68 /** Initializes the RFCOMM service, ready for new connections from a SDP client. */
  69 void RFCOMM_Initialize(void)
  70 {
  71         /* Reset the RFCOMM channel structures, to invalidate any confiured RFCOMM channels */
  72         for (uint8_t i = 0; i < RFCOMM_MAX_OPEN_CHANNELS; i++)
  73           RFCOMM_Channels[i].State = RFCOMM_Channel_Closed;
  74 }
  75
  76 void RFCOMM_ServiceChannels(Bluetooth_Channel_t* const BluetoothChannel)
  77 {
  78         for (uint8_t i = 0; i < RFCOMM_MAX_OPEN_CHANNELS; i++)
  79         {
  80                 RFCOMM_Channel_t* RFCOMMChannel = &RFCOMM_Channels[i];
  81
  82                 if (RFCOMMChannel->State == RFCOMM_Channel_Configure)
  83                 {
  84                         /* Check if the local signals have not yet been sent on the current channel */
  85                         if (!(RFCOMMChannel->ConfigFlags & RFCOMM_CONFIG_LOCALSIGNALSSENT))
  86                         {
  87                                 /* Indicate that the local signals have been sent, transmit them to the remote device */
  88                                 RFCOMMChannel->ConfigFlags |= RFCOMM_CONFIG_LOCALSIGNALSSENT;
  89                                 RFCOMM_SendChannelSignals(RFCOMMChannel, BluetoothChannel);
  90                         }
  91
  92                         /* If signals have been configured in both directions, progress to the open state */
  93                         if ((RFCOMMChannel->ConfigFlags & (RFCOMM_CONFIG_REMOTESIGNALS | RFCOMM_CONFIG_LOCALSIGNALS)) ==
  94                                                           (RFCOMM_CONFIG_REMOTESIGNALS | RFCOMM_CONFIG_LOCALSIGNALS))
  95                         {
  96                                 RFCOMMChannel->State = RFCOMM_Channel_Open;
  97                         }
  98                 }
  99         }
 100 }
 101
 102 void RFCOMM_ProcessPacket(void* Data, Bluetooth_Channel_t* const Channel)
 103 {
 104         const RFCOMM_Header_t* FrameHeader  = (const RFCOMM_Header_t*)Data;
 105         const uint8_t*         FrameData    = (const uint8_t*)Data + sizeof(RFCOMM_Header_t);
 106         uint16_t               FrameDataLen = RFCOMM_GetVariableFieldValue(&FrameData);
 107
 108         /* Decode the RFCOMM frame type from the header */
 109         switch (FrameHeader->Control & ~FRAME_POLL_FINAL)
 110         {
 111                 case RFCOMM_Frame_DM:
 112                         RFCOMM_ProcessDM(&FrameHeader->Address, Channel);
 113                         break;
 114                 case RFCOMM_Frame_DISC:
 115                         RFCOMM_ProcessDISC(&FrameHeader->Address, Channel);
 116                         break;
 117                 case RFCOMM_Frame_SABM:
 118                         RFCOMM_ProcessSABM(&FrameHeader->Address, Channel);
 119                         break;
 120                 case RFCOMM_Frame_UA:
 121                         RFCOMM_ProcessUA(&FrameHeader->Address, Channel);
 122                         break;
 123                 case RFCOMM_Frame_UIH:
 124                         RFCOMM_ProcessUIH(&FrameHeader->Address, FrameDataLen, FrameData, Channel);
 125                         break;
 126                 default:
 127                         BT_RFCOMM_DEBUG(1, "<< Unknown Frame Received");
 128                         break;
 129         }
 130 }
 131
 132 void RFCOMM_SendChannelSignals(const RFCOMM_Channel_t* const RFCOMMChannel, Bluetooth_Channel_t* const BluetoothChannel)
 133 {
 134         BT_RFCOMM_DEBUG(1, ">> MSC Command");
 135         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", RFCOMMChannel->DLCI);
 136
 137         struct
 138         {
 139                 RFCOMM_Command_t        CommandHeader;
 140                 uint8_t                 Length;
 141                 RFCOMM_MSC_Parameters_t Params;
 142         } MSCommand;
 143
 144         MSCommand.CommandHeader      = (RFCOMM_Command_t){.Command = RFCOMM_Control_ModemStatus, .EA = true, .CR = true};
 145         MSCommand.Length             = (sizeof(MSCommand.Params) << 1) | 0x01;
 146         MSCommand.Params.Channel     = (RFCOMM_Address_t){.DLCI = RFCOMMChannel->DLCI, .EA = true, .CR = true};
 147         MSCommand.Params.Signals     = RFCOMMChannel->Local.Signals;
 148         MSCommand.Params.BreakSignal = RFCOMMChannel->Local.BreakSignal;
 149
 150         /* Send the MSC command to the remote device */
 151         RFCOMM_SendFrame(RFCOMM_CONTROL_DLCI, true, RFCOMM_Frame_UIH, sizeof(MSCommand), &MSCommand, BluetoothChannel);
 152 }
 153
 154 RFCOMM_Channel_t* RFCOMM_GetChannelData(const uint8_t DLCI)
 155 {
 156         /* Search through the RFCOMM channel list, looking for the specified channel */
 157         for (uint8_t i = 0; i < RFCOMM_MAX_OPEN_CHANNELS; i++)
 158         {
 159                 RFCOMM_Channel_t* CurrRFCOMMChannel = &RFCOMM_Channels[i];
 160
 161                 /* If the current non-closed channel's DLCI matches the search DLCI, return it to the caller */
 162                 if ((CurrRFCOMMChannel->State != RFCOMM_Channel_Closed) && (CurrRFCOMMChannel->DLCI == DLCI))
 163                   return CurrRFCOMMChannel;
 164         }
 165
 166         /* Channel not found in the channel state table, return failure */
 167         return NULL;
 168 }
 169
 170 uint16_t RFCOMM_GetVariableFieldValue(const uint8_t** BufferPos)
 171 {
 172         uint8_t FirstOctet;
 173         uint8_t SecondOctet = 0;
 174
 175         FirstOctet = **BufferPos;
 176         (*BufferPos)++;
 177
 178         /* If the field size is more than a single byte, fetch the next byte in the variable length field */
 179         if (!(FirstOctet & 0x01))
 180         {
 181                 SecondOctet = **BufferPos;
 182                 (*BufferPos)++;
 183
 184                 /* Discard any remaining bytes in the variable length field that won't fit in the return value */
 185                 while (!(**BufferPos & 0x01))
 186                   (*BufferPos)++;
 187         }
 188
 189         /* Bitshift the bytes that comprise the variable length field so that they form a single integer */
 190         return (((uint16_t)SecondOctet << 7) | FirstOctet >> 1);
 191 }
 192
 193 void RFCOMM_SendFrame(const uint8_t DLCI, const bool CommandResponse, const uint8_t Control, const uint16_t DataLen,
 194                       const void* Data, Bluetooth_Channel_t* const Channel)
 195 {
 196         struct
 197         {
 198                 RFCOMM_Header_t FrameHeader;
 199                 uint8_t         Size[(DataLen < 128) ? 1 : 2];
 200                 uint8_t         Data[DataLen];
 201                 uint8_t         FCS;
 202         } ResponsePacket;
 203
 204         /* Set the frame header values to the specified address and frame type */
 205         ResponsePacket.FrameHeader.Control = Control;
 206         ResponsePacket.FrameHeader.Address = (RFCOMM_Address_t){.DLCI = DLCI, .EA   = true, .CR = CommandResponse};
 207
 208         /* Set the lower 7 bits of the packet length */
 209         ResponsePacket.Size[0] = (DataLen << 1);
 210
 211         /* Terminate the size field if size is 7 bits or lower, otherwise set the upper 8 bits of the length */
 212         if (DataLen < 128)
 213           ResponsePacket.Size[0] |= 0x01;
 214         else
 215           ResponsePacket.Size[1]  = (DataLen >> 7);
 216
 217         /* Copy over the packet data from the source buffer to the response packet buffer */
 218         memcpy(ResponsePacket.Data, Data, DataLen);
 219
 220         /* Determine the length of the frame which is to be used to calculate the CRC value */
 221         uint8_t CRCLength = sizeof(ResponsePacket.FrameHeader);
 222
 223         /* UIH frames do not have the CRC calculated on the Size field in the response, all other frames do */
 224         if ((Control & ~FRAME_POLL_FINAL) != RFCOMM_Frame_UIH)
 225           CRCLength += sizeof(ResponsePacket.Size);
 226
 227         /* Calculate the frame checksum from the appropriate fields */
 228         ResponsePacket.FCS = RFCOMM_GetFCSValue(&ResponsePacket, CRCLength);
 229
 230         /* Send the completed response packet to the sender */
 231         Bluetooth_SendPacket(&ResponsePacket, sizeof(ResponsePacket), Channel);
 232 }
 233
 234 static uint8_t RFCOMM_GetFCSValue(const void* FrameStart, uint8_t Length)
 235 {
 236         uint8_t FCS = 0xFF;
 237
 238         /* Calculate new Frame CRC value via the given data bytes and the CRC table */
 239         for (uint8_t i = 0; i < Length; i++)
 240           FCS = pgm_read_byte(&CRC8_Table[FCS ^ ((uint8_t*)FrameStart)[i]]);
 241
 242         return ~FCS;
 243 }
 244
 245 static void RFCOMM_ProcessDM(const RFCOMM_Address_t* const FrameAddress, Bluetooth_Channel_t* const Channel)
 246 {
 247         BT_RFCOMM_DEBUG(1, "<< DM Received");
 248         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameAddress->DLCI);
 249 }
 250
 251 static void RFCOMM_ProcessDISC(const RFCOMM_Address_t* const FrameAddress, Bluetooth_Channel_t* const Channel)
 252 {
 253         BT_RFCOMM_DEBUG(1, "<< DISC Received");
 254         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameAddress->DLCI);
 255
 256         RFCOMM_Channel_t* RFCOMMChannel = RFCOMM_GetChannelData(FrameAddress->DLCI);
 257
 258         /* If the requested channel is currently open, destroy it */
 259         if (RFCOMMChannel != NULL)
 260           RFCOMMChannel->State = RFCOMM_Channel_Closed;
 261
 262         BT_RFCOMM_DEBUG(1, ">> UA Sent");
 263         RFCOMM_SendFrame(FrameAddress->DLCI, true, (RFCOMM_Frame_UA | FRAME_POLL_FINAL), 0, NULL, Channel);
 264 }
 265
 266 static void RFCOMM_ProcessSABM(const RFCOMM_Address_t* const FrameAddress, Bluetooth_Channel_t* const Channel)
 267 {
 268         BT_RFCOMM_DEBUG(1, "<< SABM Received");
 269         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameAddress->DLCI);
 270
 271         RFCOMM_Channel_t* RFCOMMChannel;
 272
 273         if (FrameAddress->DLCI != RFCOMM_CONTROL_DLCI)
 274         {
 275                 /* Find a free entry in the RFCOMM channel multiplexer state array */
 276                 for (uint8_t i = 0; i < RFCOMM_MAX_OPEN_CHANNELS; i++)
 277                 {
 278                         /* If the channel's state is closed, the channel state entry is free */
 279                         if (RFCOMM_Channels[i].State == RFCOMM_Channel_Closed)
 280                         {
 281                                 RFCOMMChannel                     = &RFCOMM_Channels[i];
 282                                 RFCOMMChannel->DLCI               = FrameAddress->DLCI;
 283                                 RFCOMMChannel->State              = RFCOMM_Channel_Configure;
 284                                 RFCOMMChannel->Priority           = 7 + (RFCOMMChannel->DLCI & 0xF8);
 285                                 RFCOMMChannel->MTU                = 0xFFFF;
 286                                 RFCOMMChannel->Remote.Signals     = 0 | (1 << 0);
 287                                 RFCOMMChannel->Remote.BreakSignal = 0 | (1 << 0);
 288                                 RFCOMMChannel->Local.Signals      = RFCOMM_SIGNAL_RTC | RFCOMM_SIGNAL_RTR | RFCOMM_SIGNAL_DV | (1 << 0);
 289                                 RFCOMMChannel->Local.BreakSignal  = 0 | (1 << 0);
 290                                 RFCOMMChannel->ConfigFlags        = 0;
 291                                 break;
 292                         }
 293                 }
 294         }
 295
 296         if (RFCOMMChannel || (FrameAddress->DLCI == RFCOMM_CONTROL_DLCI))
 297         {
 298                 BT_RFCOMM_DEBUG(1, ">> UA Sent");
 299
 300                 /* Free channel found, or request was to the control channel - accept SABM by sending a UA frame */
 301                 RFCOMM_SendFrame(FrameAddress->DLCI, true, (RFCOMM_Frame_UA | FRAME_POLL_FINAL), 0, NULL, Channel);
 302         }
 303         else
 304         {
 305                 BT_RFCOMM_DEBUG(1, ">> DM Sent");
 306
 307                 /* No free channel in the multiplexer - decline the SABM by sending a DM frame */
 308                 RFCOMM_SendFrame(FrameAddress->DLCI, true, (RFCOMM_Frame_DM | FRAME_POLL_FINAL), 0, NULL, Channel);
 309         }
 310 }
 311
 312 static void RFCOMM_ProcessUA(const RFCOMM_Address_t* const FrameAddress, Bluetooth_Channel_t* const Channel)
 313 {
 314         BT_RFCOMM_DEBUG(1, "<< UA Received");
 315         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameAddress->DLCI);
 316 }
 317
 318 static void RFCOMM_ProcessUIH(const RFCOMM_Address_t* const FrameAddress, const uint16_t FrameLength,
 319                               const uint8_t* FrameData, Bluetooth_Channel_t* const Channel)
 320 {
 321         if (FrameAddress->DLCI == RFCOMM_CONTROL_DLCI)
 322         {
 323                 RFCOMM_ProcessControlCommand(FrameData, Channel);
 324                 return;
 325         }
 326
 327         BT_RFCOMM_DEBUG(1, "<< UIH Received");
 328         BT_RFCOMM_DEBUG(2, "-- DLCI 0x%02X", FrameAddress->DLCI);
 329         BT_RFCOMM_DEBUG(2, "-- Length 0x%02X", FrameLength);
 330
 331         puts("RFCOMM Data: ");
 332
 333         for (uint8_t i = 0; i < FrameLength; i++)
 334           printf("0x%02X (%c) ", FrameData[i], FrameData[i]);
 335
 336         printf("\r\n");
 337 }