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(connection_t * 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) (connection_t * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 70 static connection_t * capture_connection = NULL; 71 72 static uint8_t config_options[] = { 1, 2, 150, 0}; // mtu = 48 73 74 void l2cap_init(){ 75 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 76 // acl_buffer = malloc( 255 + 8 ); 77 acl_buffer = malloc( 400 + 8 ); 78 79 // 80 // register callback with HCI 81 // 82 hci_register_packet_handler(&l2cap_packet_handler); 83 } 84 85 86 /** Register L2CAP packet handlers */ 87 static void null_packet_handler(connection_t * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 88 } 89 void l2cap_register_packet_handler(void (*handler)(connection_t * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 90 packet_handler = handler; 91 } 92 93 // notify client/protocol handler 94 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 95 if (channel->packet_handler) { 96 (* (channel->packet_handler))(type, channel->local_cid, data, size); 97 } else { 98 switch (type){ 99 case HCI_EVENT_PACKET: 100 (*packet_handler)(channel->connection, HCI_EVENT_PACKET, 0, data, size); 101 break; 102 case L2CAP_DATA_PACKET: 103 (*packet_handler)(channel->connection, L2CAP_DATA_PACKET, channel->local_cid, data, size); 104 break; 105 default: 106 // ?? 107 break; 108 } 109 } 110 } 111 112 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 113 uint8_t event[17]; 114 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 115 event[1] = sizeof(event) - 2; 116 event[2] = status; 117 bt_flip_addr(&event[3], channel->address); 118 bt_store_16(event, 9, channel->handle); 119 bt_store_16(event, 11, channel->psm); 120 bt_store_16(event, 13, channel->local_cid); 121 bt_store_16(event, 15, channel->remote_cid); 122 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 123 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 124 } 125 126 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 127 uint8_t event[4]; 128 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 129 event[1] = sizeof(event) - 2; 130 bt_store_16(event, 2, channel->local_cid); 131 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 132 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 133 } 134 135 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 136 uint8_t event[16]; 137 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 138 event[1] = sizeof(event) - 2; 139 bt_flip_addr(&event[2], channel->address); 140 bt_store_16(event, 8, channel->handle); 141 bt_store_16(event, 10, channel->psm); 142 bt_store_16(event, 12, channel->local_cid); 143 bt_store_16(event, 14, channel->remote_cid); 144 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 145 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 146 } 147 148 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 149 linked_item_t *it; 150 l2cap_channel_t * channel; 151 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 152 channel = (l2cap_channel_t *) it; 153 if ( channel->local_cid == local_cid) { 154 return channel; 155 } 156 } 157 return NULL; 158 } 159 160 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 161 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 162 if (channel) { 163 return channel->remote_mtu; 164 } 165 return 0; 166 } 167 168 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 169 // printf("l2cap_send_signaling_packet type %u\n", cmd); 170 va_list argptr; 171 va_start(argptr, identifier); 172 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 173 va_end(argptr); 174 return hci_send_acl_packet(sig_buffer, len); 175 } 176 177 void l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 178 // find channel for local_cid, construct l2cap packet and send 179 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 180 if (channel) { 181 // 0 - Connection handle : PB=10 : BC=00 182 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 183 // 2 - ACL length 184 bt_store_16(acl_buffer, 2, len + 4); 185 // 4 - L2CAP packet length 186 bt_store_16(acl_buffer, 4, len + 0); 187 // 6 - L2CAP channel DEST 188 bt_store_16(acl_buffer, 6, channel->remote_cid); 189 // 8 - data 190 memcpy(&acl_buffer[8], data, len); 191 // send 192 hci_send_acl_packet(acl_buffer, len+8); 193 } 194 } 195 196 // open outgoing L2CAP channel 197 void l2cap_create_channel_internal(connection_t * connection, bd_addr_t address, uint16_t psm){ 198 199 // alloc structure 200 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 201 // TODO: emit error event 202 if (!chan) return; 203 204 // fill in 205 BD_ADDR_COPY(chan->address, address); 206 chan->psm = psm; 207 chan->handle = 0; 208 chan->connection = connection; 209 chan->packet_handler = NULL; 210 chan->remote_mtu = L2CAP_MINIMAL_MTU; 211 212 // set initial state 213 chan->state = L2CAP_STATE_CLOSED; 214 chan->sig_id = L2CAP_SIG_ID_INVALID; 215 216 // add to connections list 217 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 218 219 // send connection request 220 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 221 hci_send_cmd(&hci_create_connection, address, 0x18, 0, 0, 0, 0); 222 } 223 224 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 225 // find channel for local_cid 226 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 227 if (channel) { 228 channel->sig_id = l2cap_next_sig_id(); 229 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 230 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 231 } 232 } 233 234 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 235 linked_item_t *it; 236 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 237 l2cap_channel_t * channel = (l2cap_channel_t *) it; 238 if ( ! BD_ADDR_CMP( channel->address, address) ){ 239 if (channel->state == L2CAP_STATE_CLOSED) { 240 // failure, forward error code 241 l2cap_emit_channel_opened(channel, status); 242 // discard channel 243 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 244 free (channel); 245 } 246 } 247 } 248 } 249 250 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 251 linked_item_t *it; 252 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 253 l2cap_channel_t * channel = (l2cap_channel_t *) it; 254 if ( ! BD_ADDR_CMP( channel->address, address) ){ 255 if (channel->state == L2CAP_STATE_CLOSED) { 256 // success, start l2cap handshake 257 channel->handle = handle; 258 channel->sig_id = l2cap_next_sig_id(); 259 channel->local_cid = l2cap_next_local_cid(); 260 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 261 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->sig_id, channel->psm, channel->local_cid); 262 } 263 } 264 } 265 } 266 267 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 268 269 bd_addr_t address; 270 hci_con_handle_t handle; 271 272 switch(packet[0]){ 273 274 // handle connection complete events 275 case HCI_EVENT_CONNECTION_COMPLETE: 276 bt_flip_addr(address, &packet[5]); 277 if (packet[2] == 0){ 278 handle = READ_BT_16(packet, 3); 279 l2cap_handle_connection_success_for_addr(address, handle); 280 } else { 281 l2cap_handle_connection_failed_for_addr(address, packet[2]); 282 } 283 break; 284 285 // handle successful create connection cancel command 286 case HCI_EVENT_COMMAND_COMPLETE: 287 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 288 if (packet[5] == 0){ 289 bt_flip_addr(address, &packet[6]); 290 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 291 l2cap_handle_connection_failed_for_addr(address, 0x16); 292 } 293 } 294 break; 295 296 // handle disconnection complete events 297 case HCI_EVENT_DISCONNECTION_COMPLETE: 298 // send l2cap disconnect events for all channels on this handle 299 handle = READ_BT_16(packet, 3); 300 linked_item_t *it; 301 // only access next element to allows for removal 302 for (it = (linked_item_t *) &l2cap_channels; it->next ; it = it->next){ 303 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 304 if ( channel->handle == handle ){ 305 // update prev item before free'ing next element 306 it->next = it->next->next; 307 l2cap_finialize_channel_close(channel); 308 } 309 } 310 break; 311 312 // HCI Connection Timeouts 313 case L2CAP_EVENT_TIMEOUT_CHECK: 314 if (!capture_connection){ 315 hci_con_handle_t handle = READ_BT_16(packet, 2); 316 linked_item_t *it; 317 l2cap_channel_t * channel; 318 int used = 0; 319 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 320 channel = (l2cap_channel_t *) it; 321 if (channel->handle == handle) { 322 used = 1; 323 } 324 } 325 if (!used) { 326 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 327 } 328 } 329 break; 330 331 default: 332 break; 333 } 334 335 // pass on 336 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 337 } 338 339 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 340 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, identifier, channel->local_cid, channel->remote_cid); 341 l2cap_finialize_channel_close(channel); 342 } 343 344 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 345 346 // printf("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 347 l2cap_service_t *service = l2cap_get_service(psm); 348 if (!service) { 349 // 0x0002 PSM not supported 350 // printf("l2cap_handle_connection_request no PSM for psm %u/n", psm); 351 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 352 return; 353 } 354 355 hci_connection_t * hci_connection = connection_for_handle( handle ); 356 if (!hci_connection) { 357 fprintf(stderr, "no hci_connection for handle %u\n", handle); 358 // TODO: emit error 359 return; 360 } 361 // alloc structure 362 // printf("l2cap_handle_connection_request register channel\n"); 363 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 364 // TODO: emit error event 365 if (!channel) return; 366 367 // fill in 368 BD_ADDR_COPY(channel->address, hci_connection->address); 369 channel->psm = psm; 370 channel->handle = handle; 371 channel->connection = service->connection; 372 channel->packet_handler = service->packet_handler; 373 channel->local_cid = l2cap_next_local_cid(); 374 channel->remote_cid = source_cid; 375 channel->remote_mtu = L2CAP_MINIMAL_MTU; 376 377 // set initial state 378 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 379 380 // temp. store req sig id 381 channel->sig_id = sig_id; 382 383 // add to connections list 384 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 385 386 // emit incoming connection request 387 l2cap_emit_connection_request(channel); 388 } 389 390 void l2cap_accept_connection_internal(uint16_t local_cid){ 391 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 392 if (!channel) { 393 fprintf(stderr, "l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 394 return; 395 } 396 397 // accept connection 398 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, channel->local_cid, channel->remote_cid, 0, 0); 399 400 // set real sig and state and start config 401 channel->sig_id = l2cap_next_sig_id(); 402 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 403 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 404 405 // printf("new state %u\n", channel->state); 406 } 407 408 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 409 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 410 if (!channel) { 411 fprintf(stderr, "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 412 return; 413 } 414 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->sig_id, 0, 0, reason, 0); 415 416 // discard channel 417 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 418 free (channel); 419 } 420 421 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 422 // accept the other's configuration options 423 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 424 uint16_t pos = 8; 425 while (pos < end_pos){ 426 uint8_t type = command[pos++]; 427 uint8_t length = command[pos++]; 428 // MTU { type(8): 1, len(8):2, MTU(16) } 429 if ((type & 0x7f) == 1 && length == 2){ 430 channel->remote_mtu = READ_BT_16(command, pos); 431 // printf("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 432 } 433 pos += length; 434 } 435 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 436 // send back received options 437 // l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, len-4, &command[8]); 438 // send back OK 439 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->remote_cid, 0, 0, 0, NULL); 440 } 441 442 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 443 444 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 445 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 446 uint16_t result = 0; 447 448 // printf("signaling handler code %u\n", code); 449 450 switch (channel->state) { 451 452 case L2CAP_STATE_WAIT_CONNECT_RSP: 453 switch (code){ 454 case CONNECTION_RESPONSE: 455 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 456 switch (result) { 457 case 0: 458 // successful connection 459 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 460 channel->sig_id = l2cap_next_sig_id(); 461 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->remote_cid, 0, 4, &config_options); 462 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 463 break; 464 case 1: 465 // connection pending. get some coffee 466 break; 467 default: 468 // map l2cap connection response result to BTstack status enumeration 469 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 470 break; 471 } 472 break; 473 474 case DISCONNECTION_REQUEST: 475 l2cap_handle_disconnect_request(channel, identifier); 476 break; 477 478 default: 479 //@TODO: implement other signaling packets 480 break; 481 } 482 break; 483 484 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 485 switch (code) { 486 case CONFIGURE_RESPONSE: 487 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 488 break; 489 case CONFIGURE_REQUEST: 490 l2cap_signaling_handle_configure_request(channel, command); 491 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 492 break; 493 case DISCONNECTION_REQUEST: 494 l2cap_handle_disconnect_request(channel, identifier); 495 break; 496 default: 497 //@TODO: implement other signaling packets 498 break; 499 } 500 break; 501 502 case L2CAP_STATE_WAIT_CONFIG_REQ: 503 switch (code) { 504 case CONFIGURE_REQUEST: 505 l2cap_signaling_handle_configure_request(channel, command); 506 channel->state = L2CAP_STATE_OPEN; 507 l2cap_emit_channel_opened(channel, 0); // success 508 break; 509 case DISCONNECTION_REQUEST: 510 l2cap_handle_disconnect_request(channel, identifier); 511 break; 512 default: 513 //@TODO: implement other signaling packets 514 break; 515 } 516 break; 517 518 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 519 switch (code) { 520 case CONFIGURE_RESPONSE: 521 channel->state = L2CAP_STATE_OPEN; 522 l2cap_emit_channel_opened(channel, 0); // success 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_WAIT_DISCONNECT: 534 switch (code) { 535 case DISCONNECTION_RESPONSE: 536 l2cap_finialize_channel_close(channel); 537 break; 538 case DISCONNECTION_REQUEST: 539 l2cap_handle_disconnect_request(channel, identifier); 540 break; 541 default: 542 //@TODO: implement other signaling packets 543 break; 544 } 545 break; 546 547 case L2CAP_STATE_CLOSED: 548 // @TODO handle incoming requests 549 break; 550 551 case L2CAP_STATE_OPEN: 552 switch (code) { 553 case DISCONNECTION_REQUEST: 554 l2cap_handle_disconnect_request(channel, identifier); 555 break; 556 default: 557 //@TODO: implement other signaling packets, e.g. re-configure 558 break; 559 } 560 break; 561 default: 562 break; 563 } 564 // printf("new state %u\n", channel->state); 565 } 566 567 568 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 569 570 // get code, signalind identifier and command len 571 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 572 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 573 uint16_t len = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 574 575 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 576 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 577 return; 578 } 579 580 // general commands without an assigned channel 581 switch(code) { 582 583 case CONNECTION_REQUEST: { 584 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 585 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 586 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 587 break; 588 } 589 590 case ECHO_REQUEST: { 591 // send back packet 592 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, len, &command[L2CAP_SIGNALING_COMMAND_DATA_OFFSET]); 593 break; 594 } 595 596 case INFORMATION_REQUEST: { 597 // we neither support connectionless L2CAP data nor support any flow control modes yet 598 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 599 if (infoType == 2) { 600 uint32_t features = 0; 601 // extended features request supported, however no features present 602 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 603 } else { 604 // all other types are not supported 605 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 606 } 607 break;; 608 } 609 610 default: 611 break; 612 } 613 614 615 // Get potential destination CID 616 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 617 618 // Find channel for this sig_id and connection handle 619 linked_item_t *it; 620 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 621 l2cap_channel_t * channel = (l2cap_channel_t *) it; 622 if (channel->handle == handle) { 623 if (code & 1) { 624 // match odd commands by previous signaling identifier 625 if (channel->sig_id == sig_id) { 626 l2cap_signaling_handler_channel(channel, command); 627 } 628 } else { 629 // match even commands by local channel id 630 if (channel->local_cid == dest_cid) { 631 l2cap_signaling_handler_channel(channel, command); 632 } 633 } 634 } 635 } 636 } 637 638 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 639 640 // Capturing? 641 if (capture_connection) { 642 (*packet_handler)(capture_connection, HCI_ACL_DATA_PACKET, 0, packet, size); 643 return; 644 } 645 646 // Get Channel ID 647 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 648 649 // Signaling Packet? 650 if (channel_id == 1) { 651 652 // Get Connection 653 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 654 655 uint16_t command_offset = 8; 656 while (command_offset < size) { 657 658 // handle signaling commands 659 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 660 661 // increment command_offset 662 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 663 } 664 return; 665 } 666 667 // Find channel for this channel_id and connection handle 668 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 669 if (channel) { 670 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 671 } 672 } 673 674 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 675 switch (packet_type) { 676 case HCI_EVENT_PACKET: 677 l2cap_event_handler(packet, size); 678 break; 679 case HCI_ACL_DATA_PACKET: 680 l2cap_acl_handler(packet, size); 681 break; 682 default: 683 break; 684 } 685 } 686 687 // finalize closed channel 688 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 689 channel->state = L2CAP_STATE_CLOSED; 690 l2cap_emit_channel_closed(channel); 691 692 // discard channel 693 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 694 free (channel); 695 } 696 697 l2cap_service_t * l2cap_get_service(uint16_t psm){ 698 linked_item_t *it; 699 700 // close open channels 701 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 702 l2cap_service_t * service = ((l2cap_service_t *) it); 703 if ( service->psm == psm){ 704 return service; 705 }; 706 } 707 return NULL; 708 } 709 710 void l2cap_register_service_internal(connection_t *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 711 // check for alread registered psm // TODO: emit error event 712 l2cap_service_t *service = l2cap_get_service(psm); 713 if (service) return; 714 715 // alloc structure // TODO: emit error event 716 service = malloc(sizeof(l2cap_service_t)); 717 if (!service) return; 718 719 // fill in 720 service->psm = psm; 721 service->mtu = mtu; 722 service->connection = connection; 723 service->packet_handler = packet_handler; 724 725 // add to services list 726 linked_list_add(&l2cap_services, (linked_item_t *) service); 727 } 728 729 void l2cap_unregister_service_internal(connection_t *connection, uint16_t psm){ 730 l2cap_service_t *service = l2cap_get_service(psm); 731 if (!service) return; 732 linked_list_remove(&l2cap_services, (linked_item_t *) service); 733 free(service); 734 } 735 736 // 737 void l2cap_close_connection(connection_t *connection){ 738 linked_item_t *it; 739 740 // close open channels 741 l2cap_channel_t * channel; 742 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 743 channel = (l2cap_channel_t *) it; 744 if (channel->connection == connection) { 745 channel->sig_id = l2cap_next_sig_id(); 746 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->remote_cid, channel->local_cid); 747 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 748 } 749 } 750 751 // unregister services 752 it = (linked_item_t *) &l2cap_services; 753 while (it->next){ 754 l2cap_service_t * service = (l2cap_service_t *) it->next; 755 if (service->connection == connection){ 756 it->next = it->next->next; 757 free(service); 758 } else { 759 it = it->next; 760 } 761 } 762 } 763 764 765 void l2cap_set_capture_connection(connection_t * connection){ 766 capture_connection = connection; 767 } 768 769