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 // size of HCI ACL + L2CAP Header for regular data packets (8) 52 #define COMPLETE_L2CAP_HEADER (HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE) 53 54 // minimum signaling MTU 55 #define L2CAP_MINIMAL_MTU 48 56 #define L2CAP_DEFAULT_MTU 672 57 58 // determine size of outgoing packet construction buffer - this includes ACL + L2CAP header 59 #if (L2CAP_MINIMAL_MTU + L2CAP_HEADER_SIZE) > (HCI_ACL_BUFFER_SIZE) 60 #define L2CAP_PACKET_BUFFER_SIZE (HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE + L2CAP_MINIMAL_MTU) 61 #else 62 #define L2CAP_PACKET_BUFFER_SIZE (HCI_ACL_HEADER_SIZE + HCI_ACL_BUFFER_SIZE) 63 #endif 64 65 66 // nr of buffered acl packets in outgoing queue to get max performance 67 #define NR_BUFFERED_ACL_PACKETS 3 68 69 // used to cache l2cap rejects, echo, and informational requests 70 #define NR_PENDING_SIGNALING_RESPONSES 5 71 72 // offsets for L2CAP SIGNALING COMMANDS 73 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 74 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 75 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 76 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 77 78 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 79 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 80 81 // used to cache l2cap rejects, echo, and informational requests 82 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 83 static int signaling_responses_pending; 84 85 // static buffers 86 static uint8_t acl_buffer[L2CAP_PACKET_BUFFER_SIZE]; 87 88 static linked_list_t l2cap_channels = NULL; 89 static linked_list_t l2cap_services = NULL; 90 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 91 static int new_credits_blocked = 0; 92 93 // prototypes 94 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 95 static l2cap_service_t * l2cap_get_service(uint16_t psm); 96 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 97 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 98 static void l2cap_emit_connection_request(l2cap_channel_t *channel); 99 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 100 101 102 void l2cap_init(){ 103 104 new_credits_blocked = 0; 105 signaling_responses_pending = 0; 106 107 // 108 // register callback with HCI 109 // 110 hci_register_packet_handler(&l2cap_packet_handler); 111 } 112 113 114 /** Register L2CAP packet handlers */ 115 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 116 } 117 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 118 packet_handler = handler; 119 } 120 121 // notify client/protocol handler 122 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 123 if (channel->packet_handler) { 124 (* (channel->packet_handler))(type, channel->local_cid, data, size); 125 } else { 126 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 127 } 128 } 129 130 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 131 uint8_t event[21]; 132 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 133 event[1] = sizeof(event) - 2; 134 event[2] = status; 135 bt_flip_addr(&event[3], channel->address); 136 bt_store_16(event, 9, channel->handle); 137 bt_store_16(event, 11, channel->psm); 138 bt_store_16(event, 13, channel->local_cid); 139 bt_store_16(event, 15, channel->remote_cid); 140 bt_store_16(event, 17, channel->local_mtu); 141 bt_store_16(event, 19, channel->remote_mtu); 142 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 143 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 144 } 145 146 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 147 uint8_t event[4]; 148 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 149 event[1] = sizeof(event) - 2; 150 bt_store_16(event, 2, channel->local_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 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 156 uint8_t event[16]; 157 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 158 event[1] = sizeof(event) - 2; 159 bt_flip_addr(&event[2], channel->address); 160 bt_store_16(event, 8, channel->handle); 161 bt_store_16(event, 10, channel->psm); 162 bt_store_16(event, 12, channel->local_cid); 163 bt_store_16(event, 14, channel->remote_cid); 164 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 165 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 166 } 167 168 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 169 // track credits 170 channel->packets_granted += credits; 171 // log_info("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 172 173 uint8_t event[5]; 174 event[0] = L2CAP_EVENT_CREDITS; 175 event[1] = sizeof(event) - 2; 176 bt_store_16(event, 2, channel->local_cid); 177 event[4] = credits; 178 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 179 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 180 } 181 182 void l2cap_block_new_credits(uint8_t blocked){ 183 new_credits_blocked = blocked; 184 } 185 186 void l2cap_hand_out_credits(void){ 187 188 if (new_credits_blocked) return; // we're told not to. used by daemon 189 190 linked_item_t *it; 191 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 192 if (!hci_number_free_acl_slots()) return; 193 l2cap_channel_t * channel = (l2cap_channel_t *) it; 194 if (channel->state != L2CAP_STATE_OPEN) continue; 195 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 196 l2cap_emit_credits(channel, 1); 197 } 198 } 199 } 200 201 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 202 linked_item_t *it; 203 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 204 l2cap_channel_t * channel = (l2cap_channel_t *) it; 205 if ( channel->local_cid == local_cid) { 206 return channel; 207 } 208 } 209 return NULL; 210 } 211 212 int l2cap_can_send_packet_now(uint16_t local_cid){ 213 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 214 if (!channel) return 0; 215 if (!channel->packets_granted) return 0; 216 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 217 } 218 219 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 220 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 221 if (channel) { 222 return channel->remote_mtu; 223 } 224 return 0; 225 } 226 227 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 228 // log_info("l2cap_send_signaling_packet type %u\n", cmd); 229 va_list argptr; 230 va_start(argptr, identifier); 231 uint16_t len = l2cap_create_signaling_internal(acl_buffer, handle, cmd, identifier, argptr); 232 va_end(argptr); 233 // log_info("l2cap_send_signaling_packet con %u!\n", handle); 234 return hci_send_acl_packet(acl_buffer, len); 235 } 236 237 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 238 239 // check for free places on BT module 240 if (!hci_number_free_acl_slots()) { 241 log_info("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 242 return BTSTACK_ACL_BUFFERS_FULL; 243 } 244 int err = 0; 245 246 // find channel for local_cid, construct l2cap packet and send 247 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 248 if (channel) { 249 if (channel->packets_granted > 0){ 250 --channel->packets_granted; 251 // log_info("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 252 // local_cid, channel->handle, channel->packets_granted); 253 } else { 254 log_error("l2cap_send_internal cid %u, no credits!\n", local_cid); 255 } 256 257 // 0 - Connection handle : PB=10 : BC=00 258 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 259 // 2 - ACL length 260 bt_store_16(acl_buffer, 2, len + 4); 261 // 4 - L2CAP packet length 262 bt_store_16(acl_buffer, 4, len + 0); 263 // 6 - L2CAP channel DEST 264 bt_store_16(acl_buffer, 6, channel->remote_cid); 265 // 8 - data 266 memcpy(&acl_buffer[8], data, len); 267 268 // send 269 err = hci_send_acl_packet(acl_buffer, len+8); 270 } 271 272 l2cap_hand_out_credits(); 273 274 return err; 275 } 276 277 // MARK: L2CAP_RUN 278 // process outstanding signaling tasks 279 void l2cap_run(void){ 280 281 // check pending signaling responses 282 while (signaling_responses_pending){ 283 284 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 285 286 hci_con_handle_t handle = signaling_responses[0].handle; 287 uint8_t sig_id = signaling_responses[0].sig_id; 288 uint16_t infoType = signaling_responses[0].data; // INFORMATION_REQUEST 289 uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST 290 291 switch (signaling_responses[0].code){ 292 case CONNECTION_REQUEST: 293 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0); 294 break; 295 case ECHO_REQUEST: 296 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 297 break; 298 case INFORMATION_REQUEST: 299 if (infoType == 2) { 300 uint32_t features = 0; 301 // extended features request supported, however no features present 302 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 303 } else { 304 // all other types are not supported 305 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 306 } 307 break; 308 default: 309 // should not happen 310 break; 311 } 312 313 // remove first item 314 signaling_responses_pending--; 315 int i; 316 for (i=0; i < signaling_responses_pending; i++){ 317 signaling_responses[i] = signaling_responses[i+1]; 318 } 319 } 320 321 uint8_t config_options[4]; 322 linked_item_t *it; 323 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 324 325 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 326 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 327 328 l2cap_channel_t * channel = (l2cap_channel_t *) it; 329 330 // log_info("l2cap_run: state %u, var 0x%02x\n", channel->state, channel->state_var); 331 332 switch (channel->state){ 333 334 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 335 // send connection request - set state first 336 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 337 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 338 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1); 339 break; 340 341 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 342 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 343 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 344 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 345 btstack_memory_l2cap_channel_free(channel); 346 break; 347 348 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 349 channel->state = L2CAP_STATE_CONFIG; 350 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 351 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 352 break; 353 354 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 355 // success, start l2cap handshake 356 channel->local_sig_id = l2cap_next_sig_id(); 357 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 358 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 359 break; 360 361 case L2CAP_STATE_CONFIG: 362 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 363 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 364 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP; 365 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 366 } 367 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 368 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 369 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ; 370 channel->local_sig_id = l2cap_next_sig_id(); 371 config_options[0] = 1; // MTU 372 config_options[1] = 2; // len param 373 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 374 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 375 } 376 if (l2cap_channel_ready_for_open(channel)){ 377 channel->state = L2CAP_STATE_OPEN; 378 l2cap_emit_channel_opened(channel, 0); // success 379 l2cap_emit_credits(channel, 1); 380 } 381 break; 382 383 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 384 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 385 l2cap_finialize_channel_close(channel); 386 break; 387 388 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 389 channel->local_sig_id = l2cap_next_sig_id(); 390 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 391 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 392 break; 393 default: 394 break; 395 } 396 } 397 } 398 399 static uint16_t l2cap_max_l2cap_mtu(void){ 400 return hci_max_acl_data_packet_length() - L2CAP_HEADER_SIZE; 401 } 402 403 // open outgoing L2CAP channel 404 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 405 bd_addr_t address, uint16_t psm, uint16_t mtu){ 406 407 // alloc structure 408 l2cap_channel_t * chan = btstack_memory_l2cap_channel_get(); 409 if (!chan) { 410 // emit error event 411 l2cap_channel_t dummy_channel; 412 BD_ADDR_COPY(dummy_channel.address, address); 413 dummy_channel.psm = psm; 414 l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED); 415 return; 416 } 417 // limit local mtu to max acl packet length 418 if (mtu > l2cap_max_l2cap_mtu()) { 419 mtu = l2cap_max_l2cap_mtu(); 420 } 421 422 // fill in 423 BD_ADDR_COPY(chan->address, address); 424 chan->psm = psm; 425 chan->handle = 0; 426 chan->connection = connection; 427 chan->packet_handler = packet_handler; 428 chan->remote_mtu = L2CAP_MINIMAL_MTU; 429 chan->local_mtu = mtu; 430 chan->packets_granted = 0; 431 432 // set initial state 433 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 434 chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 435 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 436 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 437 438 // add to connections list 439 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 440 441 l2cap_run(); 442 } 443 444 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 445 // find channel for local_cid 446 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 447 if (channel) { 448 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 449 } 450 // process 451 l2cap_run(); 452 } 453 454 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 455 linked_item_t *it = (linked_item_t *) &l2cap_channels; 456 while (it->next){ 457 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 458 if ( ! BD_ADDR_CMP( channel->address, address) ){ 459 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 460 // failure, forward error code 461 l2cap_emit_channel_opened(channel, status); 462 // discard channel 463 it->next = it->next->next; 464 btstack_memory_l2cap_channel_free(channel); 465 } 466 } else { 467 it = it->next; 468 } 469 } 470 } 471 472 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 473 linked_item_t *it; 474 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 475 l2cap_channel_t * channel = (l2cap_channel_t *) it; 476 if ( ! BD_ADDR_CMP( channel->address, address) ){ 477 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 478 // success, start l2cap handshake 479 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 480 channel->handle = handle; 481 channel->local_cid = l2cap_next_local_cid(); 482 } 483 } 484 } 485 // process 486 l2cap_run(); 487 } 488 489 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 490 491 bd_addr_t address; 492 hci_con_handle_t handle; 493 l2cap_channel_t * channel; 494 linked_item_t *it; 495 int hci_con_used; 496 497 switch(packet[0]){ 498 499 // handle connection complete events 500 case HCI_EVENT_CONNECTION_COMPLETE: 501 bt_flip_addr(address, &packet[5]); 502 if (packet[2] == 0){ 503 handle = READ_BT_16(packet, 3); 504 l2cap_handle_connection_success_for_addr(address, handle); 505 } else { 506 l2cap_handle_connection_failed_for_addr(address, packet[2]); 507 } 508 break; 509 510 // handle successful create connection cancel command 511 case HCI_EVENT_COMMAND_COMPLETE: 512 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 513 if (packet[5] == 0){ 514 bt_flip_addr(address, &packet[6]); 515 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 516 l2cap_handle_connection_failed_for_addr(address, 0x16); 517 } 518 } 519 l2cap_run(); // try sending signaling packets first 520 break; 521 522 case HCI_EVENT_COMMAND_STATUS: 523 l2cap_run(); // try sending signaling packets first 524 break; 525 526 // handle disconnection complete events 527 case HCI_EVENT_DISCONNECTION_COMPLETE: 528 // send l2cap disconnect events for all channels on this handle 529 handle = READ_BT_16(packet, 3); 530 it = (linked_item_t *) &l2cap_channels; 531 while (it->next){ 532 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 533 if ( channel->handle == handle ){ 534 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 535 it->next = it->next->next; 536 l2cap_emit_channel_closed(channel); 537 btstack_memory_l2cap_channel_free(channel); 538 } else { 539 it = it->next; 540 } 541 } 542 break; 543 544 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 545 l2cap_run(); // try sending signaling packets first 546 l2cap_hand_out_credits(); 547 break; 548 549 // HCI Connection Timeouts 550 case L2CAP_EVENT_TIMEOUT_CHECK: 551 handle = READ_BT_16(packet, 2); 552 if (hci_authentication_active_for_handle(handle)) break; 553 hci_con_used = 0; 554 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 555 channel = (l2cap_channel_t *) it; 556 if (channel->handle == handle) { 557 hci_con_used = 1; 558 } 559 } 560 if (hci_con_used) break; 561 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 562 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 563 break; 564 565 case DAEMON_EVENT_HCI_PACKET_SENT: 566 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 567 channel = (l2cap_channel_t *) it; 568 if (channel->packet_handler) { 569 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size); 570 } 571 } 572 break; 573 574 default: 575 break; 576 } 577 578 // pass on 579 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 580 } 581 582 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 583 channel->remote_sig_id = identifier; 584 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 585 l2cap_run(); 586 } 587 588 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){ 589 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 590 signaling_responses[signaling_responses_pending].handle = handle; 591 signaling_responses[signaling_responses_pending].code = code; 592 signaling_responses[signaling_responses_pending].sig_id = sig_id; 593 signaling_responses[signaling_responses_pending].data = data; 594 signaling_responses_pending++; 595 l2cap_run(); 596 } 597 } 598 599 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 600 601 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 602 l2cap_service_t *service = l2cap_get_service(psm); 603 if (!service) { 604 // 0x0002 PSM not supported 605 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002); 606 return; 607 } 608 609 hci_connection_t * hci_connection = connection_for_handle( handle ); 610 if (!hci_connection) { 611 // 612 log_error("no hci_connection for handle %u\n", handle); 613 return; 614 } 615 // alloc structure 616 // log_info("l2cap_handle_connection_request register channel\n"); 617 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 618 if (!channel){ 619 // 0x0004 No resources available 620 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004); 621 return; 622 } 623 624 // fill in 625 BD_ADDR_COPY(channel->address, hci_connection->address); 626 channel->psm = psm; 627 channel->handle = handle; 628 channel->connection = service->connection; 629 channel->packet_handler = service->packet_handler; 630 channel->local_cid = l2cap_next_local_cid(); 631 channel->remote_cid = source_cid; 632 channel->local_mtu = service->mtu; 633 channel->remote_mtu = L2CAP_DEFAULT_MTU; 634 channel->packets_granted = 0; 635 channel->remote_sig_id = sig_id; 636 637 // limit local mtu to max acl packet length 638 if (channel->local_mtu > l2cap_max_l2cap_mtu()) { 639 channel->local_mtu = l2cap_max_l2cap_mtu(); 640 } 641 642 // set initial state 643 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 644 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 645 646 // add to connections list 647 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 648 649 // emit incoming connection request 650 l2cap_emit_connection_request(channel); 651 } 652 653 void l2cap_accept_connection_internal(uint16_t local_cid){ 654 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 655 if (!channel) { 656 log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 657 return; 658 } 659 660 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 661 662 // process 663 l2cap_run(); 664 } 665 666 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 667 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 668 if (!channel) { 669 log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 670 return; 671 } 672 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 673 channel->reason = reason; 674 l2cap_run(); 675 } 676 677 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 678 679 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 680 681 // accept the other's configuration options 682 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 683 uint16_t pos = 8; 684 while (pos < end_pos){ 685 uint8_t type = command[pos++]; 686 uint8_t length = command[pos++]; 687 // MTU { type(8): 1, len(8):2, MTU(16) } 688 if ((type & 0x7f) == 1 && length == 2){ 689 channel->remote_mtu = READ_BT_16(command, pos); 690 // log_info("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 691 } 692 pos += length; 693 } 694 } 695 696 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 697 // log_info("l2cap_channel_ready_for_open 0x%02x\n", channel->state_var); 698 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 699 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 700 return 1; 701 } 702 703 704 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 705 706 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 707 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 708 uint16_t result = 0; 709 710 log_info("signaling handler code %u, state %u\n", code, channel->state); 711 712 // handle DISCONNECT REQUESTS seperately 713 if (code == DISCONNECTION_REQUEST){ 714 switch (channel->state){ 715 case L2CAP_STATE_CONFIG: 716 case L2CAP_STATE_OPEN: 717 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 718 case L2CAP_STATE_WAIT_DISCONNECT: 719 l2cap_handle_disconnect_request(channel, identifier); 720 break; 721 722 default: 723 // ignore in other states 724 break; 725 } 726 return; 727 } 728 729 switch (channel->state) { 730 731 case L2CAP_STATE_WAIT_CONNECT_RSP: 732 switch (code){ 733 case CONNECTION_RESPONSE: 734 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 735 switch (result) { 736 case 0: 737 // successful connection 738 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 739 channel->state = L2CAP_STATE_CONFIG; 740 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 741 break; 742 case 1: 743 // connection pending. get some coffee 744 break; 745 default: 746 // channel closed 747 channel->state = L2CAP_STATE_CLOSED; 748 749 // map l2cap connection response result to BTstack status enumeration 750 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 751 752 // drop link key if security block 753 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 754 hci_drop_link_key_for_bd_addr(&channel->address); 755 } 756 757 // discard channel 758 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 759 btstack_memory_l2cap_channel_free(channel); 760 break; 761 } 762 break; 763 764 default: 765 //@TODO: implement other signaling packets 766 break; 767 } 768 break; 769 770 case L2CAP_STATE_CONFIG: 771 switch (code) { 772 case CONFIGURE_REQUEST: 773 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ; 774 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 775 l2cap_signaling_handle_configure_request(channel, command); 776 break; 777 case CONFIGURE_RESPONSE: 778 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP; 779 break; 780 default: 781 break; 782 } 783 if (l2cap_channel_ready_for_open(channel)){ 784 // for open: 785 channel->state = L2CAP_STATE_OPEN; 786 l2cap_emit_channel_opened(channel, 0); 787 l2cap_emit_credits(channel, 1); 788 } 789 break; 790 791 case L2CAP_STATE_WAIT_DISCONNECT: 792 switch (code) { 793 case DISCONNECTION_RESPONSE: 794 l2cap_finialize_channel_close(channel); 795 break; 796 default: 797 //@TODO: implement other signaling packets 798 break; 799 } 800 break; 801 802 case L2CAP_STATE_CLOSED: 803 // @TODO handle incoming requests 804 break; 805 806 case L2CAP_STATE_OPEN: 807 //@TODO: implement other signaling packets, e.g. re-configure 808 break; 809 default: 810 break; 811 } 812 // log_info("new state %u\n", channel->state); 813 } 814 815 816 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 817 818 // get code, signalind identifier and command len 819 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 820 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 821 822 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 823 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 824 return; 825 } 826 827 // general commands without an assigned channel 828 switch(code) { 829 830 case CONNECTION_REQUEST: { 831 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 832 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 833 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 834 return; 835 } 836 837 case ECHO_REQUEST: 838 l2cap_register_signaling_response(handle, code, sig_id, 0); 839 return; 840 841 case INFORMATION_REQUEST: { 842 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 843 l2cap_register_signaling_response(handle, code, sig_id, infoType); 844 return; 845 } 846 847 default: 848 break; 849 } 850 851 852 // Get potential destination CID 853 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 854 855 // Find channel for this sig_id and connection handle 856 linked_item_t *it; 857 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 858 l2cap_channel_t * channel = (l2cap_channel_t *) it; 859 if (channel->handle == handle) { 860 if (code & 1) { 861 // match odd commands (responses) by previous signaling identifier 862 if (channel->local_sig_id == sig_id) { 863 l2cap_signaling_handler_channel(channel, command); 864 break; 865 } 866 } else { 867 // match even commands (requests) by local channel id 868 if (channel->local_cid == dest_cid) { 869 l2cap_signaling_handler_channel(channel, command); 870 break; 871 } 872 } 873 } 874 } 875 } 876 877 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 878 879 // Get Channel ID 880 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 881 882 // Signaling Packet? 883 if (channel_id == 1) { 884 885 // Get Connection 886 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 887 888 uint16_t command_offset = 8; 889 while (command_offset < size) { 890 891 // handle signaling commands 892 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 893 894 // increment command_offset 895 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 896 } 897 898 l2cap_run(); 899 900 return; 901 } 902 903 // Find channel for this channel_id and connection handle 904 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 905 if (channel) { 906 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 907 } 908 } 909 910 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 911 switch (packet_type) { 912 case HCI_EVENT_PACKET: 913 l2cap_event_handler(packet, size); 914 break; 915 case HCI_ACL_DATA_PACKET: 916 l2cap_acl_handler(packet, size); 917 break; 918 default: 919 break; 920 } 921 } 922 923 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 924 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 925 channel->state = L2CAP_STATE_CLOSED; 926 l2cap_emit_channel_closed(channel); 927 // discard channel 928 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 929 btstack_memory_l2cap_channel_free(channel); 930 } 931 932 l2cap_service_t * l2cap_get_service(uint16_t psm){ 933 linked_item_t *it; 934 935 // close open channels 936 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 937 l2cap_service_t * service = ((l2cap_service_t *) it); 938 if ( service->psm == psm){ 939 return service; 940 }; 941 } 942 return NULL; 943 } 944 945 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 946 // check for alread registered psm 947 // TODO: emit error event 948 l2cap_service_t *service = l2cap_get_service(psm); 949 if (service) { 950 log_error("l2cap_register_service_internal: PSM %u already registered\n", psm); 951 return; 952 } 953 954 // alloc structure 955 // TODO: emit error event 956 service = btstack_memory_l2cap_service_get(); 957 if (!service) { 958 log_error("l2cap_register_service_internal: no memory for l2cap_service_t\n"); 959 return; 960 } 961 962 // fill in 963 service->psm = psm; 964 service->mtu = mtu; 965 service->connection = connection; 966 service->packet_handler = packet_handler; 967 968 // add to services list 969 linked_list_add(&l2cap_services, (linked_item_t *) service); 970 } 971 972 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 973 l2cap_service_t *service = l2cap_get_service(psm); 974 if (!service) return; 975 linked_list_remove(&l2cap_services, (linked_item_t *) service); 976 btstack_memory_l2cap_service_free(service); 977 } 978 979 // 980 void l2cap_close_connection(void *connection){ 981 linked_item_t *it; 982 983 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 984 l2cap_channel_t * channel; 985 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 986 channel = (l2cap_channel_t *) it; 987 if (channel->connection == connection) { 988 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 989 } 990 } 991 992 // unregister services 993 it = (linked_item_t *) &l2cap_services; 994 while (it->next) { 995 l2cap_service_t * service = (l2cap_service_t *) it->next; 996 if (service->connection == connection){ 997 it->next = it->next->next; 998 btstack_memory_l2cap_service_free(service); 999 } else { 1000 it = it->next; 1001 } 1002 } 1003 1004 // process 1005 l2cap_run(); 1006 } 1007