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 #include "btstack_memory.h" 45 46 #include <stdarg.h> 47 #include <string.h> 48 49 #include <stdio.h> 50 51 // nr of buffered acl packets in outgoing queue to get max performance 52 #define NR_BUFFERED_ACL_PACKETS 3 53 54 // used to cache l2cap rejects, echo, and informational requests 55 #define NR_PENDING_SIGNALING_RESPONSES 5 56 57 // offsets for L2CAP SIGNALING COMMANDS 58 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 59 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 60 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 61 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 62 63 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 64 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 65 66 // used to cache l2cap rejects, echo, and informational requests 67 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 68 static int signaling_responses_pending; 69 70 static linked_list_t l2cap_channels = NULL; 71 static linked_list_t l2cap_services = NULL; 72 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 73 static int new_credits_blocked = 0; 74 75 // prototypes 76 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 77 static l2cap_service_t * l2cap_get_service(uint16_t psm); 78 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 79 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 80 static void l2cap_emit_connection_request(l2cap_channel_t *channel); 81 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 82 83 84 void l2cap_init(){ 85 86 new_credits_blocked = 0; 87 signaling_responses_pending = 0; 88 89 // 90 // register callback with HCI 91 // 92 hci_register_packet_handler(&l2cap_packet_handler); 93 } 94 95 96 /** Register L2CAP packet handlers */ 97 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 98 } 99 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 100 packet_handler = handler; 101 } 102 103 // notify client/protocol handler 104 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 105 if (channel->packet_handler) { 106 (* (channel->packet_handler))(type, channel->local_cid, data, size); 107 } else { 108 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 109 } 110 } 111 112 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 113 uint8_t event[21]; 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 bt_store_16(event, 17, channel->local_mtu); 123 bt_store_16(event, 19, channel->remote_mtu); 124 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 125 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 126 } 127 128 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 129 uint8_t event[4]; 130 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 131 event[1] = sizeof(event) - 2; 132 bt_store_16(event, 2, channel->local_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 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 138 uint8_t event[16]; 139 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 140 event[1] = sizeof(event) - 2; 141 bt_flip_addr(&event[2], channel->address); 142 bt_store_16(event, 8, channel->handle); 143 bt_store_16(event, 10, channel->psm); 144 bt_store_16(event, 12, channel->local_cid); 145 bt_store_16(event, 14, channel->remote_cid); 146 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 147 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 148 } 149 150 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 151 // track credits 152 channel->packets_granted += credits; 153 // log_info("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 154 155 uint8_t event[5]; 156 event[0] = L2CAP_EVENT_CREDITS; 157 event[1] = sizeof(event) - 2; 158 bt_store_16(event, 2, channel->local_cid); 159 event[4] = credits; 160 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 161 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 162 } 163 164 void l2cap_block_new_credits(uint8_t blocked){ 165 new_credits_blocked = blocked; 166 } 167 168 void l2cap_hand_out_credits(void){ 169 170 if (new_credits_blocked) return; // we're told not to. used by daemon 171 172 linked_item_t *it; 173 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 174 if (!hci_number_free_acl_slots()) return; 175 l2cap_channel_t * channel = (l2cap_channel_t *) it; 176 if (channel->state != L2CAP_STATE_OPEN) continue; 177 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 178 l2cap_emit_credits(channel, 1); 179 } 180 } 181 } 182 183 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 184 linked_item_t *it; 185 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 186 l2cap_channel_t * channel = (l2cap_channel_t *) it; 187 if ( channel->local_cid == local_cid) { 188 return channel; 189 } 190 } 191 return NULL; 192 } 193 194 int l2cap_can_send_packet_now(uint16_t local_cid){ 195 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 196 if (!channel) return 0; 197 if (!channel->packets_granted) return 0; 198 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 199 } 200 201 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 202 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 203 if (channel) { 204 return channel->remote_mtu; 205 } 206 return 0; 207 } 208 209 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 210 211 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 212 log_info("l2cap_send_signaling_packet, cannot send\n"); 213 return BTSTACK_ACL_BUFFERS_FULL; 214 } 215 216 // log_info("l2cap_send_signaling_packet type %u\n", cmd); 217 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 218 va_list argptr; 219 va_start(argptr, identifier); 220 uint16_t len = l2cap_create_signaling_internal(acl_buffer, handle, cmd, identifier, argptr); 221 va_end(argptr); 222 // log_info("l2cap_send_signaling_packet con %u!\n", handle); 223 return hci_send_acl_packet(acl_buffer, len); 224 } 225 226 uint8_t *l2cap_get_outgoing_buffer(void){ 227 return hci_get_outgoing_acl_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes 228 } 229 230 int l2cap_send_prepared(uint16_t local_cid, uint16_t len){ 231 232 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 233 log_info("l2cap_send_internal cid %u, cannot send\n", local_cid); 234 return BTSTACK_ACL_BUFFERS_FULL; 235 } 236 237 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 238 if (!channel) { 239 log_error("l2cap_send_internal no channel for cid %u\n", local_cid); 240 return -1; // TODO: define error 241 } 242 243 if (channel->packets_granted == 0){ 244 log_error("l2cap_send_internal cid %u, no credits!\n", local_cid); 245 return -1; // TODO: define error 246 } 247 248 --channel->packets_granted; 249 250 log_debug("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 251 local_cid, channel->handle, channel->packets_granted); 252 253 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 254 255 // 0 - Connection handle : PB=10 : BC=00 256 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 257 // 2 - ACL length 258 bt_store_16(acl_buffer, 2, len + 4); 259 // 4 - L2CAP packet length 260 bt_store_16(acl_buffer, 4, len + 0); 261 // 6 - L2CAP channel DEST 262 bt_store_16(acl_buffer, 6, channel->remote_cid); 263 // send 264 int err = hci_send_acl_packet(acl_buffer, len+8); 265 266 l2cap_hand_out_credits(); 267 268 return err; 269 } 270 271 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 272 273 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 274 log_info("l2cap_send_internal cid %u, cannot send\n", local_cid); 275 return BTSTACK_ACL_BUFFERS_FULL; 276 } 277 278 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 279 280 memcpy(&acl_buffer[8], data, len); 281 282 return l2cap_send_prepared(local_cid, len); 283 } 284 285 286 // MARK: L2CAP_RUN 287 // process outstanding signaling tasks 288 void l2cap_run(void){ 289 290 // check pending signaling responses 291 while (signaling_responses_pending){ 292 293 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 294 295 hci_con_handle_t handle = signaling_responses[0].handle; 296 uint8_t sig_id = signaling_responses[0].sig_id; 297 uint16_t infoType = signaling_responses[0].data; // INFORMATION_REQUEST 298 uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST 299 300 switch (signaling_responses[0].code){ 301 case CONNECTION_REQUEST: 302 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0); 303 break; 304 case ECHO_REQUEST: 305 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 306 break; 307 case INFORMATION_REQUEST: 308 if (infoType == 2) { 309 uint32_t features = 0; 310 // extended features request supported, however no features present 311 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 312 } else { 313 // all other types are not supported 314 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 315 } 316 break; 317 default: 318 // should not happen 319 break; 320 } 321 322 // remove first item 323 signaling_responses_pending--; 324 int i; 325 for (i=0; i < signaling_responses_pending; i++){ 326 signaling_responses[i] = signaling_responses[i+1]; 327 } 328 } 329 330 uint8_t config_options[4]; 331 linked_item_t *it; 332 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 333 334 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 335 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 336 337 l2cap_channel_t * channel = (l2cap_channel_t *) it; 338 339 // log_info("l2cap_run: state %u, var 0x%02x\n", channel->state, channel->state_var); 340 341 switch (channel->state){ 342 343 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 344 // send connection request - set state first 345 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 346 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 347 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1); 348 break; 349 350 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 351 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 352 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 353 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 354 btstack_memory_l2cap_channel_free(channel); 355 break; 356 357 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 358 channel->state = L2CAP_STATE_CONFIG; 359 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 360 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 361 break; 362 363 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 364 // success, start l2cap handshake 365 channel->local_sig_id = l2cap_next_sig_id(); 366 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 367 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 368 break; 369 370 case L2CAP_STATE_CONFIG: 371 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 372 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 373 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP; 374 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 375 } 376 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 377 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 378 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ; 379 channel->local_sig_id = l2cap_next_sig_id(); 380 config_options[0] = 1; // MTU 381 config_options[1] = 2; // len param 382 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 383 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 384 } 385 if (l2cap_channel_ready_for_open(channel)){ 386 channel->state = L2CAP_STATE_OPEN; 387 l2cap_emit_channel_opened(channel, 0); // success 388 l2cap_emit_credits(channel, 1); 389 } 390 break; 391 392 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 393 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 394 l2cap_finialize_channel_close(channel); 395 break; 396 397 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 398 channel->local_sig_id = l2cap_next_sig_id(); 399 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 400 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 401 break; 402 default: 403 break; 404 } 405 } 406 } 407 408 uint16_t l2cap_max_mtu(void){ 409 return hci_max_acl_data_packet_length() - L2CAP_HEADER_SIZE; 410 } 411 412 // open outgoing L2CAP channel 413 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 414 bd_addr_t address, uint16_t psm, uint16_t mtu){ 415 416 // alloc structure 417 l2cap_channel_t * chan = btstack_memory_l2cap_channel_get(); 418 if (!chan) { 419 // emit error event 420 l2cap_channel_t dummy_channel; 421 BD_ADDR_COPY(dummy_channel.address, address); 422 dummy_channel.psm = psm; 423 l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED); 424 return; 425 } 426 // limit local mtu to max acl packet length 427 if (mtu > l2cap_max_mtu()) { 428 mtu = l2cap_max_mtu(); 429 } 430 431 // fill in 432 BD_ADDR_COPY(chan->address, address); 433 chan->psm = psm; 434 chan->handle = 0; 435 chan->connection = connection; 436 chan->packet_handler = packet_handler; 437 chan->remote_mtu = L2CAP_MINIMAL_MTU; 438 chan->local_mtu = mtu; 439 chan->packets_granted = 0; 440 441 // set initial state 442 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 443 chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 444 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 445 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 446 447 // add to connections list 448 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 449 450 l2cap_run(); 451 } 452 453 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 454 // find channel for local_cid 455 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 456 if (channel) { 457 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 458 } 459 // process 460 l2cap_run(); 461 } 462 463 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 464 linked_item_t *it = (linked_item_t *) &l2cap_channels; 465 while (it->next){ 466 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 467 if ( ! BD_ADDR_CMP( channel->address, address) ){ 468 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 469 // failure, forward error code 470 l2cap_emit_channel_opened(channel, status); 471 // discard channel 472 it->next = it->next->next; 473 btstack_memory_l2cap_channel_free(channel); 474 } 475 } else { 476 it = it->next; 477 } 478 } 479 } 480 481 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 482 linked_item_t *it; 483 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 484 l2cap_channel_t * channel = (l2cap_channel_t *) it; 485 if ( ! BD_ADDR_CMP( channel->address, address) ){ 486 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 487 // success, start l2cap handshake 488 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 489 channel->handle = handle; 490 channel->local_cid = l2cap_next_local_cid(); 491 } 492 } 493 } 494 // process 495 l2cap_run(); 496 } 497 498 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 499 500 bd_addr_t address; 501 hci_con_handle_t handle; 502 l2cap_channel_t * channel; 503 linked_item_t *it; 504 int hci_con_used; 505 506 switch(packet[0]){ 507 508 // handle connection complete events 509 case HCI_EVENT_CONNECTION_COMPLETE: 510 bt_flip_addr(address, &packet[5]); 511 if (packet[2] == 0){ 512 handle = READ_BT_16(packet, 3); 513 l2cap_handle_connection_success_for_addr(address, handle); 514 } else { 515 l2cap_handle_connection_failed_for_addr(address, packet[2]); 516 } 517 break; 518 519 // handle successful create connection cancel command 520 case HCI_EVENT_COMMAND_COMPLETE: 521 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 522 if (packet[5] == 0){ 523 bt_flip_addr(address, &packet[6]); 524 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 525 l2cap_handle_connection_failed_for_addr(address, 0x16); 526 } 527 } 528 l2cap_run(); // try sending signaling packets first 529 break; 530 531 case HCI_EVENT_COMMAND_STATUS: 532 l2cap_run(); // try sending signaling packets first 533 break; 534 535 // handle disconnection complete events 536 case HCI_EVENT_DISCONNECTION_COMPLETE: 537 // send l2cap disconnect events for all channels on this handle 538 handle = READ_BT_16(packet, 3); 539 it = (linked_item_t *) &l2cap_channels; 540 while (it->next){ 541 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 542 if ( channel->handle == handle ){ 543 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 544 it->next = it->next->next; 545 l2cap_emit_channel_closed(channel); 546 btstack_memory_l2cap_channel_free(channel); 547 } else { 548 it = it->next; 549 } 550 } 551 break; 552 553 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 554 l2cap_run(); // try sending signaling packets first 555 l2cap_hand_out_credits(); 556 break; 557 558 // HCI Connection Timeouts 559 case L2CAP_EVENT_TIMEOUT_CHECK: 560 handle = READ_BT_16(packet, 2); 561 if (hci_authentication_active_for_handle(handle)) break; 562 hci_con_used = 0; 563 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 564 channel = (l2cap_channel_t *) it; 565 if (channel->handle == handle) { 566 hci_con_used = 1; 567 } 568 } 569 if (hci_con_used) break; 570 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 571 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 572 break; 573 574 case DAEMON_EVENT_HCI_PACKET_SENT: 575 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 576 channel = (l2cap_channel_t *) it; 577 if (channel->packet_handler) { 578 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size); 579 } 580 } 581 break; 582 583 default: 584 break; 585 } 586 587 // pass on 588 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 589 } 590 591 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 592 channel->remote_sig_id = identifier; 593 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 594 l2cap_run(); 595 } 596 597 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){ 598 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 599 signaling_responses[signaling_responses_pending].handle = handle; 600 signaling_responses[signaling_responses_pending].code = code; 601 signaling_responses[signaling_responses_pending].sig_id = sig_id; 602 signaling_responses[signaling_responses_pending].data = data; 603 signaling_responses_pending++; 604 l2cap_run(); 605 } 606 } 607 608 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 609 610 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 611 l2cap_service_t *service = l2cap_get_service(psm); 612 if (!service) { 613 // 0x0002 PSM not supported 614 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002); 615 return; 616 } 617 618 hci_connection_t * hci_connection = connection_for_handle( handle ); 619 if (!hci_connection) { 620 // 621 log_error("no hci_connection for handle %u\n", handle); 622 return; 623 } 624 // alloc structure 625 // log_info("l2cap_handle_connection_request register channel\n"); 626 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 627 if (!channel){ 628 // 0x0004 No resources available 629 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004); 630 return; 631 } 632 633 // fill in 634 BD_ADDR_COPY(channel->address, hci_connection->address); 635 channel->psm = psm; 636 channel->handle = handle; 637 channel->connection = service->connection; 638 channel->packet_handler = service->packet_handler; 639 channel->local_cid = l2cap_next_local_cid(); 640 channel->remote_cid = source_cid; 641 channel->local_mtu = service->mtu; 642 channel->remote_mtu = L2CAP_DEFAULT_MTU; 643 channel->packets_granted = 0; 644 channel->remote_sig_id = sig_id; 645 646 // limit local mtu to max acl packet length 647 if (channel->local_mtu > l2cap_max_mtu()) { 648 channel->local_mtu = l2cap_max_mtu(); 649 } 650 651 // set initial state 652 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 653 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 654 655 // add to connections list 656 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 657 658 // emit incoming connection request 659 l2cap_emit_connection_request(channel); 660 } 661 662 void l2cap_accept_connection_internal(uint16_t local_cid){ 663 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 664 if (!channel) { 665 log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 666 return; 667 } 668 669 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 670 671 // process 672 l2cap_run(); 673 } 674 675 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 676 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 677 if (!channel) { 678 log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 679 return; 680 } 681 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 682 channel->reason = reason; 683 l2cap_run(); 684 } 685 686 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 687 688 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 689 690 // accept the other's configuration options 691 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 692 uint16_t pos = 8; 693 while (pos < end_pos){ 694 uint8_t type = command[pos++]; 695 uint8_t length = command[pos++]; 696 // MTU { type(8): 1, len(8):2, MTU(16) } 697 if ((type & 0x7f) == 1 && length == 2){ 698 channel->remote_mtu = READ_BT_16(command, pos); 699 // log_info("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 700 } 701 pos += length; 702 } 703 } 704 705 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 706 // log_info("l2cap_channel_ready_for_open 0x%02x\n", channel->state_var); 707 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 708 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 709 return 1; 710 } 711 712 713 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 714 715 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 716 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 717 uint16_t result = 0; 718 719 log_info("signaling handler code %u, state %u\n", code, channel->state); 720 721 // handle DISCONNECT REQUESTS seperately 722 if (code == DISCONNECTION_REQUEST){ 723 switch (channel->state){ 724 case L2CAP_STATE_CONFIG: 725 case L2CAP_STATE_OPEN: 726 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 727 case L2CAP_STATE_WAIT_DISCONNECT: 728 l2cap_handle_disconnect_request(channel, identifier); 729 break; 730 731 default: 732 // ignore in other states 733 break; 734 } 735 return; 736 } 737 738 switch (channel->state) { 739 740 case L2CAP_STATE_WAIT_CONNECT_RSP: 741 switch (code){ 742 case CONNECTION_RESPONSE: 743 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 744 switch (result) { 745 case 0: 746 // successful connection 747 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 748 channel->state = L2CAP_STATE_CONFIG; 749 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 750 break; 751 case 1: 752 // connection pending. get some coffee 753 break; 754 default: 755 // channel closed 756 channel->state = L2CAP_STATE_CLOSED; 757 758 // map l2cap connection response result to BTstack status enumeration 759 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 760 761 // drop link key if security block 762 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 763 hci_drop_link_key_for_bd_addr(&channel->address); 764 } 765 766 // discard channel 767 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 768 btstack_memory_l2cap_channel_free(channel); 769 break; 770 } 771 break; 772 773 default: 774 //@TODO: implement other signaling packets 775 break; 776 } 777 break; 778 779 case L2CAP_STATE_CONFIG: 780 switch (code) { 781 case CONFIGURE_REQUEST: 782 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ; 783 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 784 l2cap_signaling_handle_configure_request(channel, command); 785 break; 786 case CONFIGURE_RESPONSE: 787 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP; 788 break; 789 default: 790 break; 791 } 792 if (l2cap_channel_ready_for_open(channel)){ 793 // for open: 794 channel->state = L2CAP_STATE_OPEN; 795 l2cap_emit_channel_opened(channel, 0); 796 l2cap_emit_credits(channel, 1); 797 } 798 break; 799 800 case L2CAP_STATE_WAIT_DISCONNECT: 801 switch (code) { 802 case DISCONNECTION_RESPONSE: 803 l2cap_finialize_channel_close(channel); 804 break; 805 default: 806 //@TODO: implement other signaling packets 807 break; 808 } 809 break; 810 811 case L2CAP_STATE_CLOSED: 812 // @TODO handle incoming requests 813 break; 814 815 case L2CAP_STATE_OPEN: 816 //@TODO: implement other signaling packets, e.g. re-configure 817 break; 818 default: 819 break; 820 } 821 // log_info("new state %u\n", channel->state); 822 } 823 824 825 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 826 827 // get code, signalind identifier and command len 828 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 829 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 830 831 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 832 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 833 return; 834 } 835 836 // general commands without an assigned channel 837 switch(code) { 838 839 case CONNECTION_REQUEST: { 840 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 841 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 842 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 843 return; 844 } 845 846 case ECHO_REQUEST: 847 l2cap_register_signaling_response(handle, code, sig_id, 0); 848 return; 849 850 case INFORMATION_REQUEST: { 851 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 852 l2cap_register_signaling_response(handle, code, sig_id, infoType); 853 return; 854 } 855 856 default: 857 break; 858 } 859 860 861 // Get potential destination CID 862 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 863 864 // Find channel for this sig_id and connection handle 865 linked_item_t *it; 866 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 867 l2cap_channel_t * channel = (l2cap_channel_t *) it; 868 if (channel->handle == handle) { 869 if (code & 1) { 870 // match odd commands (responses) by previous signaling identifier 871 if (channel->local_sig_id == sig_id) { 872 l2cap_signaling_handler_channel(channel, command); 873 break; 874 } 875 } else { 876 // match even commands (requests) by local channel id 877 if (channel->local_cid == dest_cid) { 878 l2cap_signaling_handler_channel(channel, command); 879 break; 880 } 881 } 882 } 883 } 884 } 885 886 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 887 888 // Get Channel ID 889 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 890 891 // Signaling Packet? 892 if (channel_id == 1) { 893 894 // Get Connection 895 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 896 897 uint16_t command_offset = 8; 898 while (command_offset < size) { 899 900 // handle signaling commands 901 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 902 903 // increment command_offset 904 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 905 } 906 907 l2cap_run(); 908 909 return; 910 } 911 912 // Find channel for this channel_id and connection handle 913 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 914 if (channel) { 915 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 916 } 917 } 918 919 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 920 switch (packet_type) { 921 case HCI_EVENT_PACKET: 922 l2cap_event_handler(packet, size); 923 break; 924 case HCI_ACL_DATA_PACKET: 925 l2cap_acl_handler(packet, size); 926 break; 927 default: 928 break; 929 } 930 } 931 932 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 933 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 934 channel->state = L2CAP_STATE_CLOSED; 935 l2cap_emit_channel_closed(channel); 936 // discard channel 937 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 938 btstack_memory_l2cap_channel_free(channel); 939 } 940 941 l2cap_service_t * l2cap_get_service(uint16_t psm){ 942 linked_item_t *it; 943 944 // close open channels 945 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 946 l2cap_service_t * service = ((l2cap_service_t *) it); 947 if ( service->psm == psm){ 948 return service; 949 }; 950 } 951 return NULL; 952 } 953 954 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 955 // check for alread registered psm 956 // TODO: emit error event 957 l2cap_service_t *service = l2cap_get_service(psm); 958 if (service) { 959 log_error("l2cap_register_service_internal: PSM %u already registered\n", psm); 960 return; 961 } 962 963 // alloc structure 964 // TODO: emit error event 965 service = btstack_memory_l2cap_service_get(); 966 if (!service) { 967 log_error("l2cap_register_service_internal: no memory for l2cap_service_t\n"); 968 return; 969 } 970 971 // fill in 972 service->psm = psm; 973 service->mtu = mtu; 974 service->connection = connection; 975 service->packet_handler = packet_handler; 976 977 // add to services list 978 linked_list_add(&l2cap_services, (linked_item_t *) service); 979 } 980 981 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 982 l2cap_service_t *service = l2cap_get_service(psm); 983 if (!service) return; 984 linked_list_remove(&l2cap_services, (linked_item_t *) service); 985 btstack_memory_l2cap_service_free(service); 986 } 987 988 // 989 void l2cap_close_connection(void *connection){ 990 linked_item_t *it; 991 992 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 993 l2cap_channel_t * channel; 994 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 995 channel = (l2cap_channel_t *) it; 996 if (channel->connection == connection) { 997 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 998 } 999 } 1000 1001 // unregister services 1002 it = (linked_item_t *) &l2cap_services; 1003 while (it->next) { 1004 l2cap_service_t * service = (l2cap_service_t *) it->next; 1005 if (service->connection == connection){ 1006 it->next = it->next->next; 1007 btstack_memory_l2cap_service_free(service); 1008 } else { 1009 it = it->next; 1010 } 1011 } 1012 1013 // process 1014 l2cap_run(); 1015 } 1016