1 /* 2 * Copyright (C) 2009 by Matthias Ringwald 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 21 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 24 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 27 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 */ 31 32 /* 33 * l2cap.c 34 * 35 * Logical Link Control and Adaption Protocl (L2CAP) 36 * 37 * Created by Matthias Ringwald on 5/16/09. 38 */ 39 40 #include "l2cap.h" 41 #include "hci.h" 42 #include "hci_dump.h" 43 #include "debug.h" 44 45 #include <stdarg.h> 46 #include <string.h> 47 48 #include <stdio.h> 49 50 // size of HCI ACL + L2CAP Header for regular data packets 51 #define COMPLETE_L2CAP_HEADER 8 52 53 // minimum signaling MTU 54 #define L2CAP_MINIMAL_MTU 48 55 #define L2CAP_DEFAULT_MTU 672 56 57 // nr of buffered acl packets in outgoing queue to get max performance 58 #define NR_BUFFERED_ACL_PACKETS 3 59 60 // offsets for L2CAP SIGNALING COMMANDS 61 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 62 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 63 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 64 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 65 66 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 67 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 68 69 static uint8_t * sig_buffer = NULL; 70 static linked_list_t l2cap_channels = NULL; 71 static linked_list_t l2cap_services = NULL; 72 static uint8_t * acl_buffer = NULL; 73 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 74 static int new_credits_blocked = 0; 75 76 void l2cap_init(){ 77 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 78 acl_buffer = malloc( HCI_ACL_3DH5_SIZE); 79 80 new_credits_blocked = 0; 81 82 // 83 // register callback with HCI 84 // 85 hci_register_packet_handler(&l2cap_packet_handler); 86 } 87 88 89 /** Register L2CAP packet handlers */ 90 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 91 } 92 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 93 packet_handler = handler; 94 } 95 96 // notify client/protocol handler 97 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 98 if (channel->packet_handler) { 99 (* (channel->packet_handler))(type, channel->local_cid, data, size); 100 } else { 101 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 102 } 103 } 104 105 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 106 uint8_t event[21]; 107 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 108 event[1] = sizeof(event) - 2; 109 event[2] = status; 110 bt_flip_addr(&event[3], channel->address); 111 bt_store_16(event, 9, channel->handle); 112 bt_store_16(event, 11, channel->psm); 113 bt_store_16(event, 13, channel->local_cid); 114 bt_store_16(event, 15, channel->remote_cid); 115 bt_store_16(event, 17, channel->local_mtu); 116 bt_store_16(event, 19, channel->remote_mtu); 117 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 118 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 119 } 120 121 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 122 uint8_t event[4]; 123 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 124 event[1] = sizeof(event) - 2; 125 bt_store_16(event, 2, channel->local_cid); 126 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 127 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 128 } 129 130 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 131 uint8_t event[16]; 132 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 133 event[1] = sizeof(event) - 2; 134 bt_flip_addr(&event[2], channel->address); 135 bt_store_16(event, 8, channel->handle); 136 bt_store_16(event, 10, channel->psm); 137 bt_store_16(event, 12, channel->local_cid); 138 bt_store_16(event, 14, channel->remote_cid); 139 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 140 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 141 } 142 143 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 144 // track credits 145 channel->packets_granted += credits; 146 // log_dbg("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 147 148 uint8_t event[5]; 149 event[0] = L2CAP_EVENT_CREDITS; 150 event[1] = sizeof(event) - 2; 151 bt_store_16(event, 2, channel->local_cid); 152 event[4] = credits; 153 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 154 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 155 } 156 157 void l2cap_block_new_credits(uint8_t blocked){ 158 new_credits_blocked = blocked; 159 } 160 161 void l2cap_hand_out_credits(void){ 162 163 if (new_credits_blocked) return; // we're told not to. used by daemon 164 165 linked_item_t *it; 166 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 167 if (!hci_number_free_acl_slots()) return; 168 l2cap_channel_t * channel = (l2cap_channel_t *) it; 169 if (channel->state != L2CAP_STATE_OPEN) continue; 170 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 171 l2cap_emit_credits(channel, 1); 172 } 173 } 174 } 175 176 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 177 linked_item_t *it; 178 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 179 l2cap_channel_t * channel = (l2cap_channel_t *) it; 180 if ( channel->local_cid == local_cid) { 181 return channel; 182 } 183 } 184 return NULL; 185 } 186 187 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 188 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 189 if (channel) { 190 return channel->remote_mtu; 191 } 192 return 0; 193 } 194 195 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 196 // log_dbg("l2cap_send_signaling_packet type %u\n", cmd); 197 va_list argptr; 198 va_start(argptr, identifier); 199 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 200 va_end(argptr); 201 // log_dbg("l2cap_send_signaling_packet con %u!\n", handle); 202 return hci_send_acl_packet(sig_buffer, len); 203 } 204 205 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 206 207 // check for free places on BT module 208 if (!hci_number_free_acl_slots()) { 209 log_dbg("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 210 return BTSTACK_ACL_BUFFERS_FULL; 211 } 212 int err = 0; 213 214 // find channel for local_cid, construct l2cap packet and send 215 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 216 if (channel) { 217 if (channel->packets_granted > 0){ 218 --channel->packets_granted; 219 // log_dbg("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 220 // local_cid, channel->handle, channel->packets_granted); 221 } else { 222 log_err("l2cap_send_internal cid %u, no credits!\n", local_cid); 223 } 224 225 // 0 - Connection handle : PB=10 : BC=00 226 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 227 // 2 - ACL length 228 bt_store_16(acl_buffer, 2, len + 4); 229 // 4 - L2CAP packet length 230 bt_store_16(acl_buffer, 4, len + 0); 231 // 6 - L2CAP channel DEST 232 bt_store_16(acl_buffer, 6, channel->remote_cid); 233 // 8 - data 234 memcpy(&acl_buffer[8], data, len); 235 236 // send 237 err = hci_send_acl_packet(acl_buffer, len+8); 238 } 239 240 l2cap_hand_out_credits(); 241 242 return err; 243 } 244 245 // process outstanding signaling tasks 246 void l2cap_run(void){ 247 uint8_t config_options[4]; 248 linked_item_t *it; 249 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 250 251 // can send? 252 253 l2cap_channel_t * channel = (l2cap_channel_t *) it; 254 switch (channel->state){ 255 256 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 257 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, 0, 0, channel->reason, 0); 258 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 259 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 260 free (channel); 261 break; 262 263 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 264 // success, start l2cap handshake 265 channel->sig_id = l2cap_next_sig_id(); 266 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->sig_id, channel->psm, channel->local_cid); 267 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 268 break; 269 270 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 271 // after connection response was received 272 channel->sig_id = l2cap_next_sig_id(); 273 config_options[0] = 1; // MTU 274 config_options[1] = 2; // len param 275 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 276 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 277 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 278 break; 279 280 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 281 channel->sig_id = l2cap_next_sig_id(); 282 config_options[0] = 1; // MTU 283 config_options[1] = 2; // len param 284 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 285 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 286 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 287 break; 288 289 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 290 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->sig_id, channel->local_cid, channel->remote_cid); 291 l2cap_finialize_channel_close(channel); 292 break; 293 294 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 295 channel->sig_id = l2cap_next_sig_id(); 296 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 297 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 298 break; 299 default: 300 break; 301 } 302 } 303 } 304 305 // open outgoing L2CAP channel 306 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 307 bd_addr_t address, uint16_t psm, uint16_t mtu){ 308 309 // alloc structure 310 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 311 // TODO: emit error event 312 if (!chan) return; 313 314 // limit local mtu to max acl packet length 315 if (mtu > hci_max_acl_data_packet_length()) { 316 mtu = hci_max_acl_data_packet_length(); 317 } 318 319 // fill in 320 BD_ADDR_COPY(chan->address, address); 321 chan->psm = psm; 322 chan->handle = 0; 323 chan->connection = connection; 324 chan->packet_handler = packet_handler; 325 chan->remote_mtu = L2CAP_MINIMAL_MTU; 326 chan->local_mtu = mtu; 327 chan->packets_granted = 0; 328 329 // set initial state 330 chan->state = L2CAP_STATE_CLOSED; 331 chan->sig_id = L2CAP_SIG_ID_INVALID; 332 333 // add to connections list 334 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 335 336 // send connection request 337 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 338 hci_send_cmd(&hci_create_connection, address, 0xcc18, 0, 0, 0, 1); 339 } 340 341 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 342 // find channel for local_cid 343 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 344 if (channel) { 345 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 346 } 347 // process 348 l2cap_run(); 349 } 350 351 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 352 linked_item_t *it = (linked_item_t *) &l2cap_channels; 353 while (it->next){ 354 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 355 if ( ! BD_ADDR_CMP( channel->address, address) ){ 356 if (channel->state == L2CAP_STATE_CLOSED) { 357 // failure, forward error code 358 l2cap_emit_channel_opened(channel, status); 359 // discard channel 360 it->next = it->next->next; 361 free (channel); 362 } 363 } else { 364 it = it->next; 365 } 366 } 367 } 368 369 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 370 linked_item_t *it; 371 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 372 l2cap_channel_t * channel = (l2cap_channel_t *) it; 373 if ( ! BD_ADDR_CMP( channel->address, address) ){ 374 if (channel->state == L2CAP_STATE_CLOSED) { 375 // success, start l2cap handshake 376 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 377 channel->handle = handle; 378 channel->local_cid = l2cap_next_local_cid(); 379 } 380 } 381 } 382 // process 383 l2cap_run(); 384 } 385 386 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 387 388 bd_addr_t address; 389 hci_con_handle_t handle; 390 linked_item_t *it; 391 392 switch(packet[0]){ 393 394 // handle connection complete events 395 case HCI_EVENT_CONNECTION_COMPLETE: 396 bt_flip_addr(address, &packet[5]); 397 if (packet[2] == 0){ 398 handle = READ_BT_16(packet, 3); 399 l2cap_handle_connection_success_for_addr(address, handle); 400 } else { 401 l2cap_handle_connection_failed_for_addr(address, packet[2]); 402 } 403 break; 404 405 // handle successful create connection cancel command 406 case HCI_EVENT_COMMAND_COMPLETE: 407 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 408 if (packet[5] == 0){ 409 bt_flip_addr(address, &packet[6]); 410 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 411 l2cap_handle_connection_failed_for_addr(address, 0x16); 412 } 413 } 414 break; 415 416 // handle disconnection complete events 417 case HCI_EVENT_DISCONNECTION_COMPLETE: 418 // send l2cap disconnect events for all channels on this handle 419 handle = READ_BT_16(packet, 3); 420 it = (linked_item_t *) &l2cap_channels; 421 while (it->next){ 422 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 423 if ( channel->handle == handle ){ 424 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 425 it->next = it->next->next; 426 l2cap_emit_channel_closed(channel); 427 free (channel); 428 } else { 429 it = it->next; 430 } 431 } 432 break; 433 434 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 435 l2cap_hand_out_credits(); 436 break; 437 438 // HCI Connection Timeouts 439 case L2CAP_EVENT_TIMEOUT_CHECK: 440 handle = READ_BT_16(packet, 2); 441 if (hci_authentication_active_for_handle(handle)) break; 442 l2cap_channel_t * channel; 443 int used = 0; 444 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 445 channel = (l2cap_channel_t *) it; 446 if (channel->handle == handle) { 447 used = 1; 448 } 449 } 450 if (!used) { 451 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 452 } 453 break; 454 455 default: 456 break; 457 } 458 459 // pass on 460 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 461 } 462 463 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 464 channel->sig_id = identifier; 465 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 466 l2cap_run(); 467 } 468 469 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 470 471 // log_dbg("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 472 l2cap_service_t *service = l2cap_get_service(psm); 473 if (!service) { 474 // 0x0002 PSM not supported 475 // log_dbg("l2cap_handle_connection_request no PSM for psm %u/n", psm); 476 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 477 return; 478 } 479 480 hci_connection_t * hci_connection = connection_for_handle( handle ); 481 if (!hci_connection) { 482 log_err("no hci_connection for handle %u\n", handle); 483 // TODO: emit error 484 return; 485 } 486 // alloc structure 487 // log_dbg("l2cap_handle_connection_request register channel\n"); 488 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 489 // TODO: emit error event 490 if (!channel) return; 491 492 // fill in 493 BD_ADDR_COPY(channel->address, hci_connection->address); 494 channel->psm = psm; 495 channel->handle = handle; 496 channel->connection = service->connection; 497 channel->packet_handler = service->packet_handler; 498 channel->local_cid = l2cap_next_local_cid(); 499 channel->remote_cid = source_cid; 500 channel->local_mtu = service->mtu; 501 channel->remote_mtu = L2CAP_DEFAULT_MTU; 502 channel->packets_granted = 0; 503 504 // limit local mtu to max acl packet length 505 if (channel->local_mtu > hci_max_acl_data_packet_length()) { 506 channel->local_mtu = hci_max_acl_data_packet_length(); 507 } 508 509 // set initial state 510 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 511 512 // temp. store req sig id 513 channel->sig_id = sig_id; 514 515 // add to connections list 516 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 517 518 // emit incoming connection request 519 l2cap_emit_connection_request(channel); 520 } 521 522 void l2cap_accept_connection_internal(uint16_t local_cid){ 523 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 524 if (!channel) { 525 log_err("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 526 return; 527 } 528 529 // accept connection 530 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, channel->local_cid, channel->remote_cid, 0, 0); 531 532 // set real sig and state and start config 533 channel->sig_id = l2cap_next_sig_id(); 534 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 535 uint8_t config_options[4]; 536 config_options[0] = 1; // MTU 537 config_options[1] = 2; // len param 538 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 539 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 540 541 // log_dbg("new state %u\n", channel->state); 542 } 543 544 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 545 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 546 if (!channel) { 547 log_err( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 548 return; 549 } 550 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 551 channel->reason = reason; 552 l2cap_run(); 553 } 554 555 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 556 // accept the other's configuration options 557 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 558 uint16_t pos = 8; 559 while (pos < end_pos){ 560 uint8_t type = command[pos++]; 561 uint8_t length = command[pos++]; 562 // MTU { type(8): 1, len(8):2, MTU(16) } 563 if ((type & 0x7f) == 1 && length == 2){ 564 channel->remote_mtu = READ_BT_16(command, pos); 565 // log_dbg("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 566 } 567 pos += length; 568 } 569 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 570 // send back OK 571 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, 0, NULL); 572 } 573 574 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 575 576 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 577 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 578 uint16_t result = 0; 579 580 // log_dbg("signaling handler code %u\n", code); 581 582 switch (channel->state) { 583 584 case L2CAP_STATE_WAIT_CONNECT_RSP: 585 switch (code){ 586 case CONNECTION_RESPONSE: 587 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 588 switch (result) { 589 case 0: 590 // successful connection 591 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 592 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 593 #if 0 594 channel->state = L2CAP_STATE_OPEN; 595 l2cap_emit_channel_opened(channel, 0); // success 596 l2cap_emit_credits(channel, 1); 597 #endif 598 break; 599 case 1: 600 // connection pending. get some coffee 601 break; 602 default: 603 // channel closed 604 channel->state = L2CAP_STATE_CLOSED; 605 606 // map l2cap connection response result to BTstack status enumeration 607 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 608 609 // drop link key if security block 610 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 611 hci_drop_link_key_for_bd_addr(&channel->address); 612 } 613 614 // discard channel 615 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 616 free (channel); 617 break; 618 } 619 break; 620 621 case DISCONNECTION_REQUEST: 622 l2cap_handle_disconnect_request(channel, identifier); 623 break; 624 625 default: 626 //@TODO: implement other signaling packets 627 break; 628 } 629 break; 630 631 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 632 switch (code) { 633 case CONFIGURE_REQUEST: 634 l2cap_signaling_handle_configure_request(channel, command); 635 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP; 636 break; 637 case DISCONNECTION_REQUEST: 638 l2cap_handle_disconnect_request(channel, identifier); 639 break; 640 default: 641 //@TODO: implement other signaling packets 642 break; 643 } 644 break; 645 646 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 647 switch (code) { 648 case CONFIGURE_RESPONSE: 649 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 650 break; 651 case CONFIGURE_REQUEST: 652 l2cap_signaling_handle_configure_request(channel, command); 653 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 654 break; 655 case DISCONNECTION_REQUEST: 656 l2cap_handle_disconnect_request(channel, identifier); 657 break; 658 default: 659 //@TODO: implement other signaling packets 660 break; 661 } 662 break; 663 664 case L2CAP_STATE_WAIT_CONFIG_REQ: 665 switch (code) { 666 case CONFIGURE_REQUEST: 667 l2cap_signaling_handle_configure_request(channel, command); 668 channel->state = L2CAP_STATE_OPEN; 669 l2cap_emit_channel_opened(channel, 0); // success 670 l2cap_emit_credits(channel, 1); 671 break; 672 case DISCONNECTION_REQUEST: 673 l2cap_handle_disconnect_request(channel, identifier); 674 break; 675 default: 676 //@TODO: implement other signaling packets 677 break; 678 } 679 break; 680 681 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 682 switch (code) { 683 case CONFIGURE_RESPONSE: 684 channel->state = L2CAP_STATE_OPEN; 685 l2cap_emit_channel_opened(channel, 0); // success 686 l2cap_emit_credits(channel, 1); 687 break; 688 case DISCONNECTION_REQUEST: 689 l2cap_handle_disconnect_request(channel, identifier); 690 break; 691 default: 692 //@TODO: implement other signaling packets 693 break; 694 } 695 break; 696 697 case L2CAP_STATE_WAIT_DISCONNECT: 698 switch (code) { 699 case DISCONNECTION_RESPONSE: 700 l2cap_finialize_channel_close(channel); 701 break; 702 case DISCONNECTION_REQUEST: 703 l2cap_handle_disconnect_request(channel, identifier); 704 break; 705 default: 706 //@TODO: implement other signaling packets 707 break; 708 } 709 break; 710 711 case L2CAP_STATE_CLOSED: 712 // @TODO handle incoming requests 713 break; 714 715 case L2CAP_STATE_OPEN: 716 switch (code) { 717 case DISCONNECTION_REQUEST: 718 l2cap_handle_disconnect_request(channel, identifier); 719 break; 720 default: 721 //@TODO: implement other signaling packets, e.g. re-configure 722 break; 723 } 724 break; 725 default: 726 break; 727 } 728 // log_dbg("new state %u\n", channel->state); 729 } 730 731 732 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 733 734 // get code, signalind identifier and command len 735 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 736 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 737 uint16_t len = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 738 739 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 740 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 741 return; 742 } 743 744 // general commands without an assigned channel 745 switch(code) { 746 747 case CONNECTION_REQUEST: { 748 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 749 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 750 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 751 break; 752 } 753 754 case ECHO_REQUEST: { 755 // send back packet 756 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, len, &command[L2CAP_SIGNALING_COMMAND_DATA_OFFSET]); 757 break; 758 } 759 760 case INFORMATION_REQUEST: { 761 // we neither support connectionless L2CAP data nor support any flow control modes yet 762 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 763 if (infoType == 2) { 764 uint32_t features = 0; 765 // extended features request supported, however no features present 766 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 767 } else { 768 // all other types are not supported 769 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 770 } 771 break;; 772 } 773 774 default: 775 break; 776 } 777 778 779 // Get potential destination CID 780 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 781 782 // Find channel for this sig_id and connection handle 783 linked_item_t *it; 784 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 785 l2cap_channel_t * channel = (l2cap_channel_t *) it; 786 if (channel->handle == handle) { 787 if (code & 1) { 788 // match odd commands by previous signaling identifier 789 if (channel->sig_id == sig_id) { 790 l2cap_signaling_handler_channel(channel, command); 791 break; 792 } 793 } else { 794 // match even commands by local channel id 795 if (channel->local_cid == dest_cid) { 796 l2cap_signaling_handler_channel(channel, command); 797 break; 798 } 799 } 800 } 801 } 802 } 803 804 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 805 806 // Get Channel ID 807 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 808 809 // Signaling Packet? 810 if (channel_id == 1) { 811 812 // Get Connection 813 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 814 815 uint16_t command_offset = 8; 816 while (command_offset < size) { 817 818 // handle signaling commands 819 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 820 821 // increment command_offset 822 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 823 } 824 return; 825 } 826 827 // Find channel for this channel_id and connection handle 828 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 829 if (channel) { 830 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 831 } 832 } 833 834 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 835 switch (packet_type) { 836 case HCI_EVENT_PACKET: 837 l2cap_event_handler(packet, size); 838 break; 839 case HCI_ACL_DATA_PACKET: 840 l2cap_acl_handler(packet, size); 841 break; 842 default: 843 break; 844 } 845 } 846 847 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 848 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 849 channel->state = L2CAP_STATE_CLOSED; 850 l2cap_emit_channel_closed(channel); 851 // discard channel 852 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 853 free (channel); 854 } 855 856 l2cap_service_t * l2cap_get_service(uint16_t psm){ 857 linked_item_t *it; 858 859 // close open channels 860 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 861 l2cap_service_t * service = ((l2cap_service_t *) it); 862 if ( service->psm == psm){ 863 return service; 864 }; 865 } 866 return NULL; 867 } 868 869 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 870 // check for alread registered psm // TODO: emit error event 871 l2cap_service_t *service = l2cap_get_service(psm); 872 if (service) return; 873 874 // alloc structure // TODO: emit error event 875 service = malloc(sizeof(l2cap_service_t)); 876 if (!service) return; 877 878 // fill in 879 service->psm = psm; 880 service->mtu = mtu; 881 service->connection = connection; 882 service->packet_handler = packet_handler; 883 884 // add to services list 885 linked_list_add(&l2cap_services, (linked_item_t *) service); 886 } 887 888 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 889 l2cap_service_t *service = l2cap_get_service(psm); 890 if (!service) return; 891 linked_list_remove(&l2cap_services, (linked_item_t *) service); 892 free(service); 893 } 894 895 // 896 void l2cap_close_connection(void *connection){ 897 linked_item_t *it; 898 899 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 900 l2cap_channel_t * channel; 901 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 902 channel = (l2cap_channel_t *) it; 903 if (channel->connection == connection) { 904 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 905 } 906 } 907 908 // unregister services 909 it = (linked_item_t *) &l2cap_services; 910 while (it->next) { 911 l2cap_service_t * service = (l2cap_service_t *) it->next; 912 if (service->connection == connection){ 913 it->next = it->next->next; 914 free(service); 915 } else { 916 it = it->next; 917 } 918 } 919 920 // process 921 l2cap_run(); 922 } 923