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 44 #include <stdarg.h> 45 #include <string.h> 46 47 #include <stdio.h> 48 49 // size of HCI ACL + L2CAP Header for regular data packets 50 #define COMPLETE_L2CAP_HEADER 8 51 52 // minimum signaling MTU 53 #define L2CAP_MINIMAL_MTU 48 54 #define L2CAP_DEFAULT_MTU 672 55 56 // offsets for L2CAP SIGNALING COMMANDS 57 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 58 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 59 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 60 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 61 62 static void null_event_handler(connection_t * connection, uint8_t *packet, uint16_t size); 63 static void null_data_handler(connection_t * connection, uint16_t local_cid, uint8_t *packet, uint16_t size); 64 65 static uint8_t * sig_buffer = NULL; 66 static linked_list_t l2cap_channels = NULL; 67 static linked_list_t l2cap_services = NULL; 68 static uint8_t * acl_buffer = NULL; 69 static void (*event_packet_handler) (connection_t * connection, uint8_t *packet, uint16_t size) = null_event_handler; 70 static void (*data_packet_handler) (connection_t * connection, uint16_t local_cid, uint8_t *packet, uint16_t size) = null_data_handler; 71 static connection_t * capture_connection = NULL; 72 73 static uint8_t config_options[] = { 1, 2, 150, 0}; // mtu = 48 74 75 void l2cap_init(){ 76 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 77 // acl_buffer = malloc( 255 + 8 ); 78 acl_buffer = malloc( 400 + 8 ); 79 80 // 81 // register callbacks with HCI 82 // 83 hci_register_event_packet_handler(&l2cap_event_handler); 84 hci_register_acl_packet_handler(&l2cap_acl_handler); 85 } 86 87 88 /** Register L2CAP packet handlers */ 89 static void null_event_handler(connection_t * connection, uint8_t *packet, uint16_t size){ 90 } 91 static void null_data_handler(connection_t * connection, uint16_t local_cid, uint8_t *packet, uint16_t size){ 92 } 93 void l2cap_register_event_packet_handler(void (*handler)(connection_t * connection, uint8_t *packet, uint16_t size)){ 94 event_packet_handler = handler; 95 } 96 void l2cap_register_data_packet_handler (void (*handler)(connection_t * connection, uint16_t local_cid, uint8_t *packet, uint16_t size)){ 97 data_packet_handler = handler; 98 } 99 100 // notify client/protocol handler 101 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 102 if (channel->packet_handler) { 103 (* (channel->packet_handler))(type, channel->local_cid, data, size); 104 } else { 105 switch (type){ 106 case HCI_EVENT_PACKET: 107 (*event_packet_handler)(channel->connection, data, size); 108 break; 109 case L2CAP_DATA_PACKET: 110 (*data_packet_handler)(channel->connection, channel->local_cid, data, size); 111 break; 112 default: 113 // ?? 114 break; 115 } 116 } 117 } 118 119 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 120 uint8_t event[17]; 121 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 122 event[1] = sizeof(event) - 2; 123 event[2] = status; 124 bt_flip_addr(&event[3], channel->address); 125 bt_store_16(event, 9, channel->handle); 126 bt_store_16(event, 11, channel->psm); 127 bt_store_16(event, 13, channel->local_cid); 128 bt_store_16(event, 15, channel->remote_cid); 129 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 130 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 131 } 132 133 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 134 uint8_t event[4]; 135 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 136 event[1] = sizeof(event) - 2; 137 bt_store_16(event, 2, channel->local_cid); 138 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 139 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 140 } 141 142 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 143 uint8_t event[16]; 144 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 145 event[1] = sizeof(event) - 2; 146 bt_flip_addr(&event[2], channel->address); 147 bt_store_16(event, 8, channel->handle); 148 bt_store_16(event, 10, channel->psm); 149 bt_store_16(event, 12, channel->local_cid); 150 bt_store_16(event, 14, channel->remote_cid); 151 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 152 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 153 } 154 155 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 156 linked_item_t *it; 157 l2cap_channel_t * channel; 158 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 159 channel = (l2cap_channel_t *) it; 160 if ( channel->local_cid == local_cid) { 161 return channel; 162 } 163 } 164 return NULL; 165 } 166 167 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 168 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 169 if (channel) { 170 return channel->remote_mtu; 171 } 172 return 0; 173 } 174 175 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 176 // printf("l2cap_send_signaling_packet type %u\n", cmd); 177 va_list argptr; 178 va_start(argptr, identifier); 179 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 180 va_end(argptr); 181 return hci_send_acl_packet(sig_buffer, len); 182 } 183 184 void l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 185 // find channel for local_cid, construct l2cap packet and send 186 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 187 if (channel) { 188 // 0 - Connection handle : PB=10 : BC=00 189 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 190 // 2 - ACL length 191 bt_store_16(acl_buffer, 2, len + 4); 192 // 4 - L2CAP packet length 193 bt_store_16(acl_buffer, 4, len + 0); 194 // 6 - L2CAP channel DEST 195 bt_store_16(acl_buffer, 6, channel->remote_cid); 196 // 8 - data 197 memcpy(&acl_buffer[8], data, len); 198 // send 199 hci_send_acl_packet(acl_buffer, len+8); 200 } 201 } 202 203 // open outgoing L2CAP channel 204 void l2cap_create_channel_internal(connection_t * connection, bd_addr_t address, uint16_t psm){ 205 206 // alloc structure 207 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 208 // TODO: emit error event 209 if (!chan) return; 210 211 // fill in 212 BD_ADDR_COPY(chan->address, address); 213 chan->psm = psm; 214 chan->handle = 0; 215 chan->connection = connection; 216 chan->packet_handler = NULL; 217 chan->remote_mtu = L2CAP_MINIMAL_MTU; 218 219 // set initial state 220 chan->state = L2CAP_STATE_CLOSED; 221 chan->sig_id = L2CAP_SIG_ID_INVALID; 222 223 // add to connections list 224 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 225 226 // send connection request 227 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 228 hci_send_cmd(&hci_create_connection, address, 0x18, 0, 0, 0, 0); 229 } 230 231 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 232 // find channel for local_cid 233 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 234 if (channel) { 235 channel->sig_id = l2cap_next_sig_id(); 236 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 237 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 238 } 239 } 240 241 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 242 linked_item_t *it; 243 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 244 l2cap_channel_t * channel = (l2cap_channel_t *) it; 245 if ( ! BD_ADDR_CMP( channel->address, address) ){ 246 if (channel->state == L2CAP_STATE_CLOSED) { 247 // failure, forward error code 248 l2cap_emit_channel_opened(channel, status); 249 // discard channel 250 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 251 free (channel); 252 } 253 } 254 } 255 } 256 257 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 258 linked_item_t *it; 259 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 260 l2cap_channel_t * channel = (l2cap_channel_t *) it; 261 if ( ! BD_ADDR_CMP( channel->address, address) ){ 262 if (channel->state == L2CAP_STATE_CLOSED) { 263 // success, start l2cap handshake 264 channel->handle = handle; 265 channel->sig_id = l2cap_next_sig_id(); 266 channel->local_cid = l2cap_next_local_cid(); 267 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 268 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->sig_id, channel->psm, channel->local_cid); 269 } 270 } 271 } 272 } 273 274 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 275 276 bd_addr_t address; 277 hci_con_handle_t handle; 278 279 switch(packet[0]){ 280 281 // handle connection complete events 282 case HCI_EVENT_CONNECTION_COMPLETE: 283 bt_flip_addr(address, &packet[5]); 284 if (packet[2] == 0){ 285 handle = READ_BT_16(packet, 3); 286 l2cap_handle_connection_success_for_addr(address, handle); 287 } else { 288 l2cap_handle_connection_failed_for_addr(address, packet[2]); 289 } 290 break; 291 292 // handle successful create connection cancel command 293 case HCI_EVENT_COMMAND_COMPLETE: 294 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 295 if (packet[5] == 0){ 296 bt_flip_addr(address, &packet[6]); 297 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 298 l2cap_handle_connection_failed_for_addr(address, 0x16); 299 } 300 } 301 break; 302 303 // handle disconnection complete events 304 case HCI_EVENT_DISCONNECTION_COMPLETE: 305 // send l2cap disconnect events for all channels on this handle 306 handle = READ_BT_16(packet, 3); 307 linked_item_t *it; 308 // only access next element to allows for removal 309 for (it = (linked_item_t *) &l2cap_channels; it ; it = it->next){ 310 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 311 if ( channel->handle == handle ){ 312 // update prev item before free'ing next element 313 it->next = it->next->next; 314 l2cap_finialize_channel_close(channel); 315 } 316 } 317 break; 318 319 // HCI Connection Timeouts 320 case L2CAP_EVENT_TIMEOUT_CHECK: 321 if (!capture_connection){ 322 hci_con_handle_t handle = READ_BT_16(packet, 2); 323 linked_item_t *it; 324 l2cap_channel_t * channel; 325 int used = 0; 326 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 327 channel = (l2cap_channel_t *) it; 328 if (channel->handle == handle) { 329 used = 1; 330 } 331 } 332 if (!used) { 333 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 334 } 335 } 336 break; 337 338 default: 339 break; 340 } 341 342 // pass on 343 (*event_packet_handler)(NULL, packet, size); 344 } 345 346 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 347 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, identifier, channel->local_cid, channel->remote_cid); 348 l2cap_finialize_channel_close(channel); 349 } 350 351 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 352 353 // printf("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 354 l2cap_service_t *service = l2cap_get_service(psm); 355 if (!service) { 356 // 0x0002 PSM not supported 357 // printf("l2cap_handle_connection_request no PSM for psm %u/n", psm); 358 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 359 return; 360 } 361 362 hci_connection_t * hci_connection = connection_for_handle( handle ); 363 if (!hci_connection) { 364 fprintf(stderr, "no hci_connection for handle %u\n", handle); 365 // TODO: emit error 366 return; 367 } 368 // alloc structure 369 // printf("l2cap_handle_connection_request register channel\n"); 370 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 371 // TODO: emit error event 372 if (!channel) return; 373 374 // fill in 375 BD_ADDR_COPY(channel->address, hci_connection->address); 376 channel->psm = psm; 377 channel->handle = handle; 378 channel->connection = service->connection; 379 channel->packet_handler = service->packet_handler; 380 channel->local_cid = l2cap_next_local_cid(); 381 channel->remote_cid = source_cid; 382 channel->remote_mtu = L2CAP_MINIMAL_MTU; 383 384 // set initial state 385 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 386 387 // temp. store req sig id 388 channel->sig_id = sig_id; 389 390 // add to connections list 391 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 392 393 // emit incoming connection request 394 l2cap_emit_connection_request(channel); 395 } 396 397 void l2cap_accept_connection_internal(uint16_t local_cid){ 398 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 399 if (!channel) { 400 fprintf(stderr, "l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 401 return; 402 } 403 404 // accept connection 405 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, channel->local_cid, channel->remote_cid, 0, 0); 406 407 // set real sig and state and start config 408 channel->sig_id = l2cap_next_sig_id(); 409 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 410 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 411 412 // printf("new state %u\n", channel->state); 413 } 414 415 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 416 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 417 if (!channel) { 418 fprintf(stderr, "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 419 return; 420 } 421 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, 0, 0, reason, 0); 422 423 // discard channel 424 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 425 free (channel); 426 } 427 428 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 429 // accept the other's configuration options 430 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 431 uint16_t pos = 8; 432 while (pos < end_pos){ 433 uint8_t type = command[pos++]; 434 uint8_t length = command[pos++]; 435 // MTU { type(8): 1, len(8):2, MTU(16) } 436 if ((type & 0x7f) == 1 && length == 2){ 437 channel->remote_mtu = READ_BT_16(command, pos); 438 // printf("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 439 } 440 pos += length; 441 } 442 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 443 // send back received options 444 // l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, len-4, &command[8]); 445 // send back OK 446 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, 0, NULL); 447 } 448 449 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 450 451 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 452 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 453 uint16_t result = 0; 454 455 // printf("signaling handler code %u\n", code); 456 457 switch (channel->state) { 458 459 case L2CAP_STATE_WAIT_CONNECT_RSP: 460 switch (code){ 461 case CONNECTION_RESPONSE: 462 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 463 switch (result) { 464 case 0: 465 // successful connection 466 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 467 channel->sig_id = l2cap_next_sig_id(); 468 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 469 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 470 break; 471 case 1: 472 // connection pending. get some coffee 473 break; 474 default: 475 // map l2cap connection response result to BTstack status enumeration 476 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 477 break; 478 } 479 break; 480 481 case DISCONNECTION_REQUEST: 482 l2cap_handle_disconnect_request(channel, identifier); 483 break; 484 485 default: 486 //@TODO: implement other signaling packets 487 break; 488 } 489 break; 490 491 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 492 switch (code) { 493 case CONFIGURE_RESPONSE: 494 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 495 break; 496 case CONFIGURE_REQUEST: 497 l2cap_signaling_handle_configure_request(channel, command); 498 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 499 break; 500 case DISCONNECTION_REQUEST: 501 l2cap_handle_disconnect_request(channel, identifier); 502 break; 503 default: 504 //@TODO: implement other signaling packets 505 break; 506 } 507 break; 508 509 case L2CAP_STATE_WAIT_CONFIG_REQ: 510 switch (code) { 511 case CONFIGURE_REQUEST: 512 l2cap_signaling_handle_configure_request(channel, command); 513 channel->state = L2CAP_STATE_OPEN; 514 l2cap_emit_channel_opened(channel, 0); // success 515 break; 516 case DISCONNECTION_REQUEST: 517 l2cap_handle_disconnect_request(channel, identifier); 518 break; 519 default: 520 //@TODO: implement other signaling packets 521 break; 522 } 523 break; 524 525 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 526 switch (code) { 527 case CONFIGURE_RESPONSE: 528 channel->state = L2CAP_STATE_OPEN; 529 l2cap_emit_channel_opened(channel, 0); // success 530 break; 531 case DISCONNECTION_REQUEST: 532 l2cap_handle_disconnect_request(channel, identifier); 533 break; 534 default: 535 //@TODO: implement other signaling packets 536 break; 537 } 538 break; 539 540 case L2CAP_STATE_WAIT_DISCONNECT: 541 switch (code) { 542 case DISCONNECTION_RESPONSE: 543 l2cap_finialize_channel_close(channel); 544 break; 545 case DISCONNECTION_REQUEST: 546 l2cap_handle_disconnect_request(channel, identifier); 547 break; 548 default: 549 //@TODO: implement other signaling packets 550 break; 551 } 552 break; 553 554 case L2CAP_STATE_CLOSED: 555 // @TODO handle incoming requests 556 break; 557 558 case L2CAP_STATE_OPEN: 559 switch (code) { 560 case DISCONNECTION_REQUEST: 561 l2cap_handle_disconnect_request(channel, identifier); 562 break; 563 default: 564 //@TODO: implement other signaling packets, e.g. re-configure 565 break; 566 } 567 break; 568 default: 569 break; 570 } 571 // printf("new state %u\n", channel->state); 572 } 573 574 575 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 576 577 // get code, signalind identifier and command len 578 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 579 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 580 uint16_t len = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 581 582 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 583 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 584 return; 585 } 586 587 // general commands without an assigned channel 588 switch(code) { 589 590 case CONNECTION_REQUEST: { 591 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 592 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 593 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 594 break; 595 } 596 597 case ECHO_REQUEST: { 598 // send back packet 599 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, len, &command[L2CAP_SIGNALING_COMMAND_DATA_OFFSET]); 600 break; 601 } 602 603 case INFORMATION_REQUEST: { 604 // we neither support connectionless L2CAP data nor support any flow control modes yet 605 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 606 if (infoType == 2) { 607 uint32_t features = 0; 608 // extended features request supported, however no features present 609 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 610 } else { 611 // all other types are not supported 612 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 613 } 614 break;; 615 } 616 617 default: 618 break; 619 } 620 621 622 // Get potential destination CID 623 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 624 625 // Find channel for this sig_id and connection handle 626 linked_item_t *it; 627 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 628 l2cap_channel_t * channel = (l2cap_channel_t *) it; 629 if (channel->handle == handle) { 630 if (code & 1) { 631 // match odd commands by previous signaling identifier 632 if (channel->sig_id == sig_id) { 633 l2cap_signaling_handler_channel(channel, command); 634 } 635 } else { 636 // match even commands by local channel id 637 if (channel->local_cid == dest_cid) { 638 l2cap_signaling_handler_channel(channel, command); 639 } 640 } 641 } 642 } 643 } 644 645 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 646 647 // Capturing? 648 if (capture_connection) { 649 (*data_packet_handler)(capture_connection, 0, packet, size); 650 return; 651 } 652 653 // Get Channel ID 654 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 655 656 // Signaling Packet? 657 if (channel_id == 1) { 658 659 // Get Connection 660 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 661 662 uint16_t command_offset = 8; 663 while (command_offset < size) { 664 665 // handle signaling commands 666 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 667 668 // increment command_offset 669 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 670 } 671 return; 672 } 673 674 // Find channel for this channel_id and connection handle 675 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 676 if (channel) { 677 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 678 } 679 } 680 681 682 // finalize closed channel 683 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 684 channel->state = L2CAP_STATE_CLOSED; 685 l2cap_emit_channel_closed(channel); 686 687 // discard channel 688 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 689 free (channel); 690 } 691 692 l2cap_service_t * l2cap_get_service(uint16_t psm){ 693 linked_item_t *it; 694 695 // close open channels 696 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 697 l2cap_service_t * service = ((l2cap_service_t *) it); 698 if ( service->psm == psm){ 699 return service; 700 }; 701 } 702 return NULL; 703 } 704 705 void l2cap_register_service_internal(connection_t *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 706 // check for alread registered psm // TODO: emit error event 707 l2cap_service_t *service = l2cap_get_service(psm); 708 if (service) return; 709 710 // alloc structure // TODO: emit error event 711 service = malloc(sizeof(l2cap_service_t)); 712 if (!service) return; 713 714 // fill in 715 service->psm = psm; 716 service->mtu = mtu; 717 service->connection = connection; 718 service->packet_handler = packet_handler; 719 720 // add to services list 721 linked_list_add(&l2cap_services, (linked_item_t *) service); 722 } 723 724 void l2cap_unregister_service_internal(connection_t *connection, uint16_t psm){ 725 l2cap_service_t *service = l2cap_get_service(psm); 726 if (!service) return; 727 linked_list_remove(&l2cap_services, (linked_item_t *) service); 728 free(service); 729 } 730 731 // 732 void l2cap_close_connection(connection_t *connection){ 733 linked_item_t *it; 734 735 // close open channels 736 l2cap_channel_t * channel; 737 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 738 channel = (l2cap_channel_t *) it; 739 if (channel->connection == connection) { 740 channel->sig_id = l2cap_next_sig_id(); 741 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 742 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 743 } 744 } 745 746 // unregister services 747 it = (linked_item_t *) &l2cap_services; 748 while (it->next){ 749 l2cap_service_t * service = (l2cap_service_t *) it->next; 750 if (service->connection == connection){ 751 it->next = it->next->next; 752 free(service); 753 } else { 754 it = it->next; 755 } 756 } 757 } 758 759 760 void l2cap_set_capture_connection(connection_t * connection){ 761 capture_connection = connection; 762 } 763 764