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_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 63 static void l2cap_packet_handler(uint8_t packet_type, 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 (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 70 71 static uint8_t config_options[] = { 1, 2, 150, 0}; // mtu = 48 72 73 void l2cap_init(){ 74 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 75 // acl_buffer = malloc( 255 + 8 ); 76 acl_buffer = malloc( 400 + 8 ); 77 78 // 79 // register callback with HCI 80 // 81 hci_register_packet_handler(&l2cap_packet_handler); 82 } 83 84 85 /** Register L2CAP packet handlers */ 86 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 87 } 88 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 89 packet_handler = handler; 90 } 91 92 // notify client/protocol handler 93 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 94 if (channel->packet_handler) { 95 (* (channel->packet_handler))(type, channel->local_cid, data, size); 96 } else { 97 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 98 } 99 } 100 101 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 102 uint8_t event[17]; 103 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 104 event[1] = sizeof(event) - 2; 105 event[2] = status; 106 bt_flip_addr(&event[3], channel->address); 107 bt_store_16(event, 9, channel->handle); 108 bt_store_16(event, 11, channel->psm); 109 bt_store_16(event, 13, channel->local_cid); 110 bt_store_16(event, 15, channel->remote_cid); 111 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 112 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 113 } 114 115 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 116 uint8_t event[4]; 117 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 118 event[1] = sizeof(event) - 2; 119 bt_store_16(event, 2, channel->local_cid); 120 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 121 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 122 } 123 124 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 125 uint8_t event[16]; 126 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 127 event[1] = sizeof(event) - 2; 128 bt_flip_addr(&event[2], channel->address); 129 bt_store_16(event, 8, channel->handle); 130 bt_store_16(event, 10, channel->psm); 131 bt_store_16(event, 12, channel->local_cid); 132 bt_store_16(event, 14, channel->remote_cid); 133 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 134 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 135 } 136 137 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 138 linked_item_t *it; 139 l2cap_channel_t * channel; 140 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 141 channel = (l2cap_channel_t *) it; 142 if ( channel->local_cid == local_cid) { 143 return channel; 144 } 145 } 146 return NULL; 147 } 148 149 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 150 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 151 if (channel) { 152 return channel->remote_mtu; 153 } 154 return 0; 155 } 156 157 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 158 // printf("l2cap_send_signaling_packet type %u\n", cmd); 159 va_list argptr; 160 va_start(argptr, identifier); 161 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 162 va_end(argptr); 163 return hci_send_acl_packet(sig_buffer, len); 164 } 165 166 void l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 167 // find channel for local_cid, construct l2cap packet and send 168 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 169 if (channel) { 170 // 0 - Connection handle : PB=10 : BC=00 171 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 172 // 2 - ACL length 173 bt_store_16(acl_buffer, 2, len + 4); 174 // 4 - L2CAP packet length 175 bt_store_16(acl_buffer, 4, len + 0); 176 // 6 - L2CAP channel DEST 177 bt_store_16(acl_buffer, 6, channel->remote_cid); 178 // 8 - data 179 memcpy(&acl_buffer[8], data, len); 180 // send 181 hci_send_acl_packet(acl_buffer, len+8); 182 } 183 } 184 185 // open outgoing L2CAP channel 186 void l2cap_create_channel_internal(void * connection, bd_addr_t address, uint16_t psm){ 187 188 // alloc structure 189 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 190 // TODO: emit error event 191 if (!chan) return; 192 193 // fill in 194 BD_ADDR_COPY(chan->address, address); 195 chan->psm = psm; 196 chan->handle = 0; 197 chan->connection = connection; 198 chan->packet_handler = NULL; 199 chan->remote_mtu = L2CAP_MINIMAL_MTU; 200 201 // set initial state 202 chan->state = L2CAP_STATE_CLOSED; 203 chan->sig_id = L2CAP_SIG_ID_INVALID; 204 205 // add to connections list 206 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 207 208 // send connection request 209 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 210 hci_send_cmd(&hci_create_connection, address, 0x18, 0, 0, 0, 0); 211 } 212 213 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 214 // find channel for local_cid 215 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 216 if (channel) { 217 channel->sig_id = l2cap_next_sig_id(); 218 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 219 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 220 } 221 } 222 223 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 224 linked_item_t *it; 225 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 226 l2cap_channel_t * channel = (l2cap_channel_t *) it; 227 if ( ! BD_ADDR_CMP( channel->address, address) ){ 228 if (channel->state == L2CAP_STATE_CLOSED) { 229 // failure, forward error code 230 l2cap_emit_channel_opened(channel, status); 231 // discard channel 232 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 233 free (channel); 234 } 235 } 236 } 237 } 238 239 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 240 linked_item_t *it; 241 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 242 l2cap_channel_t * channel = (l2cap_channel_t *) it; 243 if ( ! BD_ADDR_CMP( channel->address, address) ){ 244 if (channel->state == L2CAP_STATE_CLOSED) { 245 // success, start l2cap handshake 246 channel->handle = handle; 247 channel->sig_id = l2cap_next_sig_id(); 248 channel->local_cid = l2cap_next_local_cid(); 249 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 250 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->sig_id, channel->psm, channel->local_cid); 251 } 252 } 253 } 254 } 255 256 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 257 258 bd_addr_t address; 259 hci_con_handle_t handle; 260 linked_item_t *it; 261 262 switch(packet[0]){ 263 264 // handle connection complete events 265 case HCI_EVENT_CONNECTION_COMPLETE: 266 bt_flip_addr(address, &packet[5]); 267 if (packet[2] == 0){ 268 handle = READ_BT_16(packet, 3); 269 l2cap_handle_connection_success_for_addr(address, handle); 270 } else { 271 l2cap_handle_connection_failed_for_addr(address, packet[2]); 272 } 273 break; 274 275 // handle successful create connection cancel command 276 case HCI_EVENT_COMMAND_COMPLETE: 277 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 278 if (packet[5] == 0){ 279 bt_flip_addr(address, &packet[6]); 280 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 281 l2cap_handle_connection_failed_for_addr(address, 0x16); 282 } 283 } 284 break; 285 286 // handle disconnection complete events 287 case HCI_EVENT_DISCONNECTION_COMPLETE: 288 // send l2cap disconnect events for all channels on this handle 289 handle = READ_BT_16(packet, 3); 290 // only access next element to allows for removal 291 for (it = (linked_item_t *) &l2cap_channels; it->next ; it = it->next){ 292 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 293 if ( channel->handle == handle ){ 294 // update prev item before free'ing next element 295 it->next = it->next->next; 296 l2cap_finialize_channel_close(channel); 297 } 298 } 299 break; 300 301 // HCI Connection Timeouts 302 case L2CAP_EVENT_TIMEOUT_CHECK: 303 handle = READ_BT_16(packet, 2); 304 l2cap_channel_t * channel; 305 int used = 0; 306 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 307 channel = (l2cap_channel_t *) it; 308 if (channel->handle == handle) { 309 used = 1; 310 } 311 } 312 if (!used) { 313 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 314 } 315 break; 316 317 default: 318 break; 319 } 320 321 // pass on 322 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 323 } 324 325 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 326 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, identifier, channel->local_cid, channel->remote_cid); 327 l2cap_finialize_channel_close(channel); 328 } 329 330 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 331 332 // printf("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 333 l2cap_service_t *service = l2cap_get_service(psm); 334 if (!service) { 335 // 0x0002 PSM not supported 336 // printf("l2cap_handle_connection_request no PSM for psm %u/n", psm); 337 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 338 return; 339 } 340 341 hci_connection_t * hci_connection = connection_for_handle( handle ); 342 if (!hci_connection) { 343 fprintf(stderr, "no hci_connection for handle %u\n", handle); 344 // TODO: emit error 345 return; 346 } 347 // alloc structure 348 // printf("l2cap_handle_connection_request register channel\n"); 349 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 350 // TODO: emit error event 351 if (!channel) return; 352 353 // fill in 354 BD_ADDR_COPY(channel->address, hci_connection->address); 355 channel->psm = psm; 356 channel->handle = handle; 357 channel->connection = service->connection; 358 channel->packet_handler = service->packet_handler; 359 channel->local_cid = l2cap_next_local_cid(); 360 channel->remote_cid = source_cid; 361 channel->remote_mtu = L2CAP_MINIMAL_MTU; 362 363 // set initial state 364 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 365 366 // temp. store req sig id 367 channel->sig_id = sig_id; 368 369 // add to connections list 370 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 371 372 // emit incoming connection request 373 l2cap_emit_connection_request(channel); 374 } 375 376 void l2cap_accept_connection_internal(uint16_t local_cid){ 377 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 378 if (!channel) { 379 fprintf(stderr, "l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 380 return; 381 } 382 383 // accept connection 384 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, channel->local_cid, channel->remote_cid, 0, 0); 385 386 // set real sig and state and start config 387 channel->sig_id = l2cap_next_sig_id(); 388 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 389 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 390 391 // printf("new state %u\n", channel->state); 392 } 393 394 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 395 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 396 if (!channel) { 397 fprintf(stderr, "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 398 return; 399 } 400 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, 0, 0, reason, 0); 401 402 // discard channel 403 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 404 free (channel); 405 } 406 407 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 408 // accept the other's configuration options 409 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 410 uint16_t pos = 8; 411 while (pos < end_pos){ 412 uint8_t type = command[pos++]; 413 uint8_t length = command[pos++]; 414 // MTU { type(8): 1, len(8):2, MTU(16) } 415 if ((type & 0x7f) == 1 && length == 2){ 416 channel->remote_mtu = READ_BT_16(command, pos); 417 // printf("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 418 } 419 pos += length; 420 } 421 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 422 // send back received options 423 // l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, len-4, &command[8]); 424 // send back OK 425 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, 0, NULL); 426 } 427 428 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 429 430 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 431 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 432 uint16_t result = 0; 433 434 // printf("signaling handler code %u\n", code); 435 436 switch (channel->state) { 437 438 case L2CAP_STATE_WAIT_CONNECT_RSP: 439 switch (code){ 440 case CONNECTION_RESPONSE: 441 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 442 switch (result) { 443 case 0: 444 // successful connection 445 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 446 channel->sig_id = l2cap_next_sig_id(); 447 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 448 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 449 break; 450 case 1: 451 // connection pending. get some coffee 452 break; 453 default: 454 // map l2cap connection response result to BTstack status enumeration 455 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 456 break; 457 } 458 break; 459 460 case DISCONNECTION_REQUEST: 461 l2cap_handle_disconnect_request(channel, identifier); 462 break; 463 464 default: 465 //@TODO: implement other signaling packets 466 break; 467 } 468 break; 469 470 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 471 switch (code) { 472 case CONFIGURE_RESPONSE: 473 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 474 break; 475 case CONFIGURE_REQUEST: 476 l2cap_signaling_handle_configure_request(channel, command); 477 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 478 break; 479 case DISCONNECTION_REQUEST: 480 l2cap_handle_disconnect_request(channel, identifier); 481 break; 482 default: 483 //@TODO: implement other signaling packets 484 break; 485 } 486 break; 487 488 case L2CAP_STATE_WAIT_CONFIG_REQ: 489 switch (code) { 490 case CONFIGURE_REQUEST: 491 l2cap_signaling_handle_configure_request(channel, command); 492 channel->state = L2CAP_STATE_OPEN; 493 l2cap_emit_channel_opened(channel, 0); // success 494 break; 495 case DISCONNECTION_REQUEST: 496 l2cap_handle_disconnect_request(channel, identifier); 497 break; 498 default: 499 //@TODO: implement other signaling packets 500 break; 501 } 502 break; 503 504 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 505 switch (code) { 506 case CONFIGURE_RESPONSE: 507 channel->state = L2CAP_STATE_OPEN; 508 l2cap_emit_channel_opened(channel, 0); // success 509 break; 510 case DISCONNECTION_REQUEST: 511 l2cap_handle_disconnect_request(channel, identifier); 512 break; 513 default: 514 //@TODO: implement other signaling packets 515 break; 516 } 517 break; 518 519 case L2CAP_STATE_WAIT_DISCONNECT: 520 switch (code) { 521 case DISCONNECTION_RESPONSE: 522 l2cap_finialize_channel_close(channel); 523 break; 524 case DISCONNECTION_REQUEST: 525 l2cap_handle_disconnect_request(channel, identifier); 526 break; 527 default: 528 //@TODO: implement other signaling packets 529 break; 530 } 531 break; 532 533 case L2CAP_STATE_CLOSED: 534 // @TODO handle incoming requests 535 break; 536 537 case L2CAP_STATE_OPEN: 538 switch (code) { 539 case DISCONNECTION_REQUEST: 540 l2cap_handle_disconnect_request(channel, identifier); 541 break; 542 default: 543 //@TODO: implement other signaling packets, e.g. re-configure 544 break; 545 } 546 break; 547 default: 548 break; 549 } 550 // printf("new state %u\n", channel->state); 551 } 552 553 554 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 555 556 // get code, signalind identifier and command len 557 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 558 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 559 uint16_t len = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 560 561 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 562 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 563 return; 564 } 565 566 // general commands without an assigned channel 567 switch(code) { 568 569 case CONNECTION_REQUEST: { 570 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 571 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 572 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 573 break; 574 } 575 576 case ECHO_REQUEST: { 577 // send back packet 578 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, len, &command[L2CAP_SIGNALING_COMMAND_DATA_OFFSET]); 579 break; 580 } 581 582 case INFORMATION_REQUEST: { 583 // we neither support connectionless L2CAP data nor support any flow control modes yet 584 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 585 if (infoType == 2) { 586 uint32_t features = 0; 587 // extended features request supported, however no features present 588 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 589 } else { 590 // all other types are not supported 591 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 592 } 593 break;; 594 } 595 596 default: 597 break; 598 } 599 600 601 // Get potential destination CID 602 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 603 604 // Find channel for this sig_id and connection handle 605 linked_item_t *it; 606 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 607 l2cap_channel_t * channel = (l2cap_channel_t *) it; 608 if (channel->handle == handle) { 609 if (code & 1) { 610 // match odd commands by previous signaling identifier 611 if (channel->sig_id == sig_id) { 612 l2cap_signaling_handler_channel(channel, command); 613 } 614 } else { 615 // match even commands by local channel id 616 if (channel->local_cid == dest_cid) { 617 l2cap_signaling_handler_channel(channel, command); 618 } 619 } 620 } 621 } 622 } 623 624 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 625 626 // Get Channel ID 627 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 628 629 // Signaling Packet? 630 if (channel_id == 1) { 631 632 // Get Connection 633 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 634 635 uint16_t command_offset = 8; 636 while (command_offset < size) { 637 638 // handle signaling commands 639 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 640 641 // increment command_offset 642 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 643 } 644 return; 645 } 646 647 // Find channel for this channel_id and connection handle 648 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 649 if (channel) { 650 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 651 } 652 } 653 654 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 655 switch (packet_type) { 656 case HCI_EVENT_PACKET: 657 l2cap_event_handler(packet, size); 658 break; 659 case HCI_ACL_DATA_PACKET: 660 l2cap_acl_handler(packet, size); 661 break; 662 default: 663 break; 664 } 665 } 666 667 // finalize closed channel 668 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 669 channel->state = L2CAP_STATE_CLOSED; 670 l2cap_emit_channel_closed(channel); 671 672 // discard channel 673 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 674 free (channel); 675 } 676 677 l2cap_service_t * l2cap_get_service(uint16_t psm){ 678 linked_item_t *it; 679 680 // close open channels 681 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 682 l2cap_service_t * service = ((l2cap_service_t *) it); 683 if ( service->psm == psm){ 684 return service; 685 }; 686 } 687 return NULL; 688 } 689 690 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 691 // check for alread registered psm // TODO: emit error event 692 l2cap_service_t *service = l2cap_get_service(psm); 693 if (service) return; 694 695 // alloc structure // TODO: emit error event 696 service = malloc(sizeof(l2cap_service_t)); 697 if (!service) return; 698 699 // fill in 700 service->psm = psm; 701 service->mtu = mtu; 702 service->connection = connection; 703 service->packet_handler = packet_handler; 704 705 // add to services list 706 linked_list_add(&l2cap_services, (linked_item_t *) service); 707 } 708 709 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 710 l2cap_service_t *service = l2cap_get_service(psm); 711 if (!service) return; 712 linked_list_remove(&l2cap_services, (linked_item_t *) service); 713 free(service); 714 } 715 716 // 717 void l2cap_close_connection(void *connection){ 718 linked_item_t *it; 719 720 // close open channels 721 l2cap_channel_t * channel; 722 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 723 channel = (l2cap_channel_t *) it; 724 if (channel->connection == connection) { 725 channel->sig_id = l2cap_next_sig_id(); 726 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 727 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 728 } 729 } 730 731 // unregister services 732 it = (linked_item_t *) &l2cap_services; 733 while (it->next){ 734 l2cap_service_t * service = (l2cap_service_t *) it->next; 735 if (service->connection == connection){ 736 it->next = it->next->next; 737 free(service); 738 } else { 739 it = it->next; 740 } 741 } 742 } 743