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 #define L2CAP_HEADER_SIZE 4 52 53 // size of HCI ACL + L2CAP Header for regular data packets (8) 54 #define COMPLETE_L2CAP_HEADER (HCI_ACL_DATA_PKT_HDR + L2CAP_HEADER_SIZE) 55 56 // minimum signaling MTU 57 #define L2CAP_MINIMAL_MTU 48 58 #define L2CAP_DEFAULT_MTU 672 59 60 // nr of buffered acl packets in outgoing queue to get max performance 61 #define NR_BUFFERED_ACL_PACKETS 3 62 63 // used to cache l2cap rejects, echo, and informational requests 64 #define NR_PENDING_SIGNALING_RESPONSES 5 65 66 // offsets for L2CAP SIGNALING COMMANDS 67 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 68 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 69 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 70 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 71 72 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 73 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 74 75 // used to cache l2cap rejects, echo, and informational requests 76 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 77 static int signaling_responses_pending; 78 79 // static buffers 80 static uint8_t sig_buffer[HCI_ACL_DATA_PKT_HDR + L2CAP_HEADER_SIZE + L2CAP_MINIMAL_MTU]; 81 static uint8_t acl_buffer[HCI_ACL_DATA_PKT_HDR + HCI_ACL_BUFFER_SIZE]; 82 83 static linked_list_t l2cap_channels = NULL; 84 static linked_list_t l2cap_services = NULL; 85 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 86 static int new_credits_blocked = 0; 87 88 // prototypes 89 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 90 static l2cap_service_t * l2cap_get_service(uint16_t psm); 91 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 92 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 93 static void l2cap_emit_connection_request(l2cap_channel_t *channel); 94 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 95 96 97 void l2cap_init(){ 98 99 new_credits_blocked = 0; 100 signaling_responses_pending = 0; 101 102 // 103 // register callback with HCI 104 // 105 hci_register_packet_handler(&l2cap_packet_handler); 106 } 107 108 109 /** Register L2CAP packet handlers */ 110 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 111 } 112 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 113 packet_handler = handler; 114 } 115 116 // notify client/protocol handler 117 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 118 if (channel->packet_handler) { 119 (* (channel->packet_handler))(type, channel->local_cid, data, size); 120 } else { 121 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 122 } 123 } 124 125 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 126 uint8_t event[21]; 127 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 128 event[1] = sizeof(event) - 2; 129 event[2] = status; 130 bt_flip_addr(&event[3], channel->address); 131 bt_store_16(event, 9, channel->handle); 132 bt_store_16(event, 11, channel->psm); 133 bt_store_16(event, 13, channel->local_cid); 134 bt_store_16(event, 15, channel->remote_cid); 135 bt_store_16(event, 17, channel->local_mtu); 136 bt_store_16(event, 19, channel->remote_mtu); 137 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 138 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 139 } 140 141 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 142 uint8_t event[4]; 143 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 144 event[1] = sizeof(event) - 2; 145 bt_store_16(event, 2, channel->local_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_connection_request(l2cap_channel_t *channel) { 151 uint8_t event[16]; 152 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 153 event[1] = sizeof(event) - 2; 154 bt_flip_addr(&event[2], channel->address); 155 bt_store_16(event, 8, channel->handle); 156 bt_store_16(event, 10, channel->psm); 157 bt_store_16(event, 12, channel->local_cid); 158 bt_store_16(event, 14, channel->remote_cid); 159 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 160 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 161 } 162 163 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 164 // track credits 165 channel->packets_granted += credits; 166 // log_info("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 167 168 uint8_t event[5]; 169 event[0] = L2CAP_EVENT_CREDITS; 170 event[1] = sizeof(event) - 2; 171 bt_store_16(event, 2, channel->local_cid); 172 event[4] = credits; 173 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 174 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 175 } 176 177 void l2cap_block_new_credits(uint8_t blocked){ 178 new_credits_blocked = blocked; 179 } 180 181 void l2cap_hand_out_credits(void){ 182 183 if (new_credits_blocked) return; // we're told not to. used by daemon 184 185 linked_item_t *it; 186 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 187 if (!hci_number_free_acl_slots()) return; 188 l2cap_channel_t * channel = (l2cap_channel_t *) it; 189 if (channel->state != L2CAP_STATE_OPEN) continue; 190 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 191 l2cap_emit_credits(channel, 1); 192 } 193 } 194 } 195 196 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 197 linked_item_t *it; 198 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 199 l2cap_channel_t * channel = (l2cap_channel_t *) it; 200 if ( channel->local_cid == local_cid) { 201 return channel; 202 } 203 } 204 return NULL; 205 } 206 207 int l2cap_can_send_packet_now(uint16_t local_cid){ 208 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 209 if (!channel) return 0; 210 if (!channel->packets_granted) return 0; 211 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 212 } 213 214 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 215 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 216 if (channel) { 217 return channel->remote_mtu; 218 } 219 return 0; 220 } 221 222 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 223 // log_info("l2cap_send_signaling_packet type %u\n", cmd); 224 va_list argptr; 225 va_start(argptr, identifier); 226 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 227 va_end(argptr); 228 // log_info("l2cap_send_signaling_packet con %u!\n", handle); 229 return hci_send_acl_packet(sig_buffer, len); 230 } 231 232 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 233 234 // check for free places on BT module 235 if (!hci_number_free_acl_slots()) { 236 log_info("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 237 return BTSTACK_ACL_BUFFERS_FULL; 238 } 239 int err = 0; 240 241 // find channel for local_cid, construct l2cap packet and send 242 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 243 if (channel) { 244 if (channel->packets_granted > 0){ 245 --channel->packets_granted; 246 // log_info("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 247 // local_cid, channel->handle, channel->packets_granted); 248 } else { 249 log_error("l2cap_send_internal cid %u, no credits!\n", local_cid); 250 } 251 252 // 0 - Connection handle : PB=10 : BC=00 253 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 254 // 2 - ACL length 255 bt_store_16(acl_buffer, 2, len + 4); 256 // 4 - L2CAP packet length 257 bt_store_16(acl_buffer, 4, len + 0); 258 // 6 - L2CAP channel DEST 259 bt_store_16(acl_buffer, 6, channel->remote_cid); 260 // 8 - data 261 memcpy(&acl_buffer[8], data, len); 262 263 // send 264 err = hci_send_acl_packet(acl_buffer, len+8); 265 } 266 267 l2cap_hand_out_credits(); 268 269 return err; 270 } 271 272 // MARK: L2CAP_RUN 273 // process outstanding signaling tasks 274 void l2cap_run(void){ 275 276 // check pending signaling responses 277 while (signaling_responses_pending){ 278 279 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 280 281 hci_con_handle_t handle = signaling_responses[0].handle; 282 uint8_t sig_id = signaling_responses[0].sig_id; 283 uint16_t infoType = signaling_responses[0].data; // INFORMATION_REQUEST 284 uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST 285 286 switch (signaling_responses[0].code){ 287 case CONNECTION_REQUEST: 288 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0); 289 break; 290 case ECHO_REQUEST: 291 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 292 break; 293 case INFORMATION_REQUEST: 294 if (infoType == 2) { 295 uint32_t features = 0; 296 // extended features request supported, however no features present 297 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 298 } else { 299 // all other types are not supported 300 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 301 } 302 break; 303 default: 304 // should not happen 305 break; 306 } 307 308 // remove first item 309 signaling_responses_pending--; 310 int i; 311 for (i=0; i < signaling_responses_pending; i++){ 312 signaling_responses[i] = signaling_responses[i+1]; 313 } 314 } 315 316 uint8_t config_options[4]; 317 linked_item_t *it; 318 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 319 320 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 321 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 322 323 l2cap_channel_t * channel = (l2cap_channel_t *) it; 324 325 // log_info("l2cap_run: state %u, var 0x%02x\n", channel->state, channel->state_var); 326 327 switch (channel->state){ 328 329 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 330 // send connection request - set state first 331 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 332 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 333 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1); 334 break; 335 336 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 337 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 338 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 339 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 340 btstack_memory_l2cap_channel_free(channel); 341 break; 342 343 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 344 channel->state = L2CAP_STATE_CONFIG; 345 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 346 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 347 break; 348 349 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 350 // success, start l2cap handshake 351 channel->local_sig_id = l2cap_next_sig_id(); 352 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 353 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 354 break; 355 356 case L2CAP_STATE_CONFIG: 357 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 358 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 359 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP; 360 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 361 } 362 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 363 channel->state_var &= ~L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 364 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ; 365 channel->local_sig_id = l2cap_next_sig_id(); 366 config_options[0] = 1; // MTU 367 config_options[1] = 2; // len param 368 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 369 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 370 } 371 if (l2cap_channel_ready_for_open(channel)){ 372 channel->state = L2CAP_STATE_OPEN; 373 l2cap_emit_channel_opened(channel, 0); // success 374 l2cap_emit_credits(channel, 1); 375 } 376 break; 377 378 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 379 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 380 l2cap_finialize_channel_close(channel); 381 break; 382 383 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 384 channel->local_sig_id = l2cap_next_sig_id(); 385 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 386 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 387 break; 388 default: 389 break; 390 } 391 } 392 } 393 394 static uint16_t l2cap_max_l2cap_mtu(void){ 395 return hci_max_acl_data_packet_length()-4; // 4 bytes for L2CAP header 396 } 397 398 // open outgoing L2CAP channel 399 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 400 bd_addr_t address, uint16_t psm, uint16_t mtu){ 401 402 // alloc structure 403 l2cap_channel_t * chan = btstack_memory_l2cap_channel_get(); 404 if (!chan) { 405 // emit error event 406 l2cap_channel_t dummy_channel; 407 BD_ADDR_COPY(dummy_channel.address, address); 408 dummy_channel.psm = psm; 409 l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED); 410 return; 411 } 412 // limit local mtu to max acl packet length 413 if (mtu > l2cap_max_l2cap_mtu()) { 414 mtu = l2cap_max_l2cap_mtu(); 415 } 416 417 // fill in 418 BD_ADDR_COPY(chan->address, address); 419 chan->psm = psm; 420 chan->handle = 0; 421 chan->connection = connection; 422 chan->packet_handler = packet_handler; 423 chan->remote_mtu = L2CAP_MINIMAL_MTU; 424 chan->local_mtu = mtu; 425 chan->packets_granted = 0; 426 427 // set initial state 428 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 429 chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 430 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 431 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 432 433 // add to connections list 434 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 435 436 l2cap_run(); 437 } 438 439 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 440 // find channel for local_cid 441 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 442 if (channel) { 443 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 444 } 445 // process 446 l2cap_run(); 447 } 448 449 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 450 linked_item_t *it = (linked_item_t *) &l2cap_channels; 451 while (it->next){ 452 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 453 if ( ! BD_ADDR_CMP( channel->address, address) ){ 454 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 455 // failure, forward error code 456 l2cap_emit_channel_opened(channel, status); 457 // discard channel 458 it->next = it->next->next; 459 btstack_memory_l2cap_channel_free(channel); 460 } 461 } else { 462 it = it->next; 463 } 464 } 465 } 466 467 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 468 linked_item_t *it; 469 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 470 l2cap_channel_t * channel = (l2cap_channel_t *) it; 471 if ( ! BD_ADDR_CMP( channel->address, address) ){ 472 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 473 // success, start l2cap handshake 474 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 475 channel->handle = handle; 476 channel->local_cid = l2cap_next_local_cid(); 477 } 478 } 479 } 480 // process 481 l2cap_run(); 482 } 483 484 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 485 486 bd_addr_t address; 487 hci_con_handle_t handle; 488 l2cap_channel_t * channel; 489 linked_item_t *it; 490 int hci_con_used; 491 492 switch(packet[0]){ 493 494 // handle connection complete events 495 case HCI_EVENT_CONNECTION_COMPLETE: 496 bt_flip_addr(address, &packet[5]); 497 if (packet[2] == 0){ 498 handle = READ_BT_16(packet, 3); 499 l2cap_handle_connection_success_for_addr(address, handle); 500 } else { 501 l2cap_handle_connection_failed_for_addr(address, packet[2]); 502 } 503 break; 504 505 // handle successful create connection cancel command 506 case HCI_EVENT_COMMAND_COMPLETE: 507 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 508 if (packet[5] == 0){ 509 bt_flip_addr(address, &packet[6]); 510 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 511 l2cap_handle_connection_failed_for_addr(address, 0x16); 512 } 513 } 514 l2cap_run(); // try sending signaling packets first 515 break; 516 517 case HCI_EVENT_COMMAND_STATUS: 518 l2cap_run(); // try sending signaling packets first 519 break; 520 521 // handle disconnection complete events 522 case HCI_EVENT_DISCONNECTION_COMPLETE: 523 // send l2cap disconnect events for all channels on this handle 524 handle = READ_BT_16(packet, 3); 525 it = (linked_item_t *) &l2cap_channels; 526 while (it->next){ 527 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 528 if ( channel->handle == handle ){ 529 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 530 it->next = it->next->next; 531 l2cap_emit_channel_closed(channel); 532 btstack_memory_l2cap_channel_free(channel); 533 } else { 534 it = it->next; 535 } 536 } 537 break; 538 539 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 540 l2cap_run(); // try sending signaling packets first 541 l2cap_hand_out_credits(); 542 break; 543 544 // HCI Connection Timeouts 545 case L2CAP_EVENT_TIMEOUT_CHECK: 546 handle = READ_BT_16(packet, 2); 547 if (hci_authentication_active_for_handle(handle)) break; 548 hci_con_used = 0; 549 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 550 channel = (l2cap_channel_t *) it; 551 if (channel->handle == handle) { 552 hci_con_used = 1; 553 } 554 } 555 if (hci_con_used) break; 556 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 557 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 558 break; 559 560 case DAEMON_EVENT_HCI_PACKET_SENT: 561 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 562 channel = (l2cap_channel_t *) it; 563 if (channel->packet_handler) { 564 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size); 565 } 566 } 567 break; 568 569 default: 570 break; 571 } 572 573 // pass on 574 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 575 } 576 577 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 578 channel->remote_sig_id = identifier; 579 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 580 l2cap_run(); 581 } 582 583 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){ 584 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 585 signaling_responses[signaling_responses_pending].handle = handle; 586 signaling_responses[signaling_responses_pending].code = code; 587 signaling_responses[signaling_responses_pending].sig_id = sig_id; 588 signaling_responses[signaling_responses_pending].data = data; 589 signaling_responses_pending++; 590 l2cap_run(); 591 } 592 } 593 594 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 595 596 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 597 l2cap_service_t *service = l2cap_get_service(psm); 598 if (!service) { 599 // 0x0002 PSM not supported 600 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002); 601 return; 602 } 603 604 hci_connection_t * hci_connection = connection_for_handle( handle ); 605 if (!hci_connection) { 606 // 607 log_error("no hci_connection for handle %u\n", handle); 608 return; 609 } 610 // alloc structure 611 // log_info("l2cap_handle_connection_request register channel\n"); 612 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 613 if (!channel){ 614 // 0x0004 No resources available 615 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004); 616 return; 617 } 618 619 // fill in 620 BD_ADDR_COPY(channel->address, hci_connection->address); 621 channel->psm = psm; 622 channel->handle = handle; 623 channel->connection = service->connection; 624 channel->packet_handler = service->packet_handler; 625 channel->local_cid = l2cap_next_local_cid(); 626 channel->remote_cid = source_cid; 627 channel->local_mtu = service->mtu; 628 channel->remote_mtu = L2CAP_DEFAULT_MTU; 629 channel->packets_granted = 0; 630 channel->remote_sig_id = sig_id; 631 632 // limit local mtu to max acl packet length 633 if (channel->local_mtu > l2cap_max_l2cap_mtu()) { 634 channel->local_mtu = l2cap_max_l2cap_mtu(); 635 } 636 637 // set initial state 638 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 639 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 640 641 // add to connections list 642 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 643 644 // emit incoming connection request 645 l2cap_emit_connection_request(channel); 646 } 647 648 void l2cap_accept_connection_internal(uint16_t local_cid){ 649 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 650 if (!channel) { 651 log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 652 return; 653 } 654 655 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 656 657 // process 658 l2cap_run(); 659 } 660 661 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 662 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 663 if (!channel) { 664 log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 665 return; 666 } 667 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 668 channel->reason = reason; 669 l2cap_run(); 670 } 671 672 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 673 674 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 675 676 // accept the other's configuration options 677 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 678 uint16_t pos = 8; 679 while (pos < end_pos){ 680 uint8_t type = command[pos++]; 681 uint8_t length = command[pos++]; 682 // MTU { type(8): 1, len(8):2, MTU(16) } 683 if ((type & 0x7f) == 1 && length == 2){ 684 channel->remote_mtu = READ_BT_16(command, pos); 685 // log_info("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 686 } 687 pos += length; 688 } 689 } 690 691 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 692 // log_info("l2cap_channel_ready_for_open 0x%02x\n", channel->state_var); 693 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 694 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 695 return 1; 696 } 697 698 699 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 700 701 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 702 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 703 uint16_t result = 0; 704 705 log_info("signaling handler code %u, state %u\n", code, channel->state); 706 707 // handle DISCONNECT REQUESTS seperately 708 if (code == DISCONNECTION_REQUEST){ 709 switch (channel->state){ 710 case L2CAP_STATE_CONFIG: 711 case L2CAP_STATE_OPEN: 712 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 713 case L2CAP_STATE_WAIT_DISCONNECT: 714 l2cap_handle_disconnect_request(channel, identifier); 715 break; 716 717 default: 718 // ignore in other states 719 break; 720 } 721 return; 722 } 723 724 switch (channel->state) { 725 726 case L2CAP_STATE_WAIT_CONNECT_RSP: 727 switch (code){ 728 case CONNECTION_RESPONSE: 729 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 730 switch (result) { 731 case 0: 732 // successful connection 733 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 734 channel->state = L2CAP_STATE_CONFIG; 735 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ; 736 break; 737 case 1: 738 // connection pending. get some coffee 739 break; 740 default: 741 // channel closed 742 channel->state = L2CAP_STATE_CLOSED; 743 744 // map l2cap connection response result to BTstack status enumeration 745 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 746 747 // drop link key if security block 748 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 749 hci_drop_link_key_for_bd_addr(&channel->address); 750 } 751 752 // discard channel 753 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 754 btstack_memory_l2cap_channel_free(channel); 755 break; 756 } 757 break; 758 759 default: 760 //@TODO: implement other signaling packets 761 break; 762 } 763 break; 764 765 case L2CAP_STATE_CONFIG: 766 switch (code) { 767 case CONFIGURE_REQUEST: 768 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ; 769 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP; 770 l2cap_signaling_handle_configure_request(channel, command); 771 break; 772 case CONFIGURE_RESPONSE: 773 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP; 774 break; 775 default: 776 break; 777 } 778 if (l2cap_channel_ready_for_open(channel)){ 779 // for open: 780 channel->state = L2CAP_STATE_OPEN; 781 l2cap_emit_channel_opened(channel, 0); 782 l2cap_emit_credits(channel, 1); 783 } 784 break; 785 786 case L2CAP_STATE_WAIT_DISCONNECT: 787 switch (code) { 788 case DISCONNECTION_RESPONSE: 789 l2cap_finialize_channel_close(channel); 790 break; 791 default: 792 //@TODO: implement other signaling packets 793 break; 794 } 795 break; 796 797 case L2CAP_STATE_CLOSED: 798 // @TODO handle incoming requests 799 break; 800 801 case L2CAP_STATE_OPEN: 802 //@TODO: implement other signaling packets, e.g. re-configure 803 break; 804 default: 805 break; 806 } 807 // log_info("new state %u\n", channel->state); 808 } 809 810 811 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 812 813 // get code, signalind identifier and command len 814 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 815 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 816 817 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 818 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 819 return; 820 } 821 822 // general commands without an assigned channel 823 switch(code) { 824 825 case CONNECTION_REQUEST: { 826 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 827 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 828 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 829 return; 830 } 831 832 case ECHO_REQUEST: 833 l2cap_register_signaling_response(handle, code, sig_id, 0); 834 return; 835 836 case INFORMATION_REQUEST: { 837 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 838 l2cap_register_signaling_response(handle, code, sig_id, infoType); 839 return; 840 } 841 842 default: 843 break; 844 } 845 846 847 // Get potential destination CID 848 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 849 850 // Find channel for this sig_id and connection handle 851 linked_item_t *it; 852 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 853 l2cap_channel_t * channel = (l2cap_channel_t *) it; 854 if (channel->handle == handle) { 855 if (code & 1) { 856 // match odd commands (responses) by previous signaling identifier 857 if (channel->local_sig_id == sig_id) { 858 l2cap_signaling_handler_channel(channel, command); 859 break; 860 } 861 } else { 862 // match even commands (requests) by local channel id 863 if (channel->local_cid == dest_cid) { 864 l2cap_signaling_handler_channel(channel, command); 865 break; 866 } 867 } 868 } 869 } 870 } 871 872 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 873 874 // Get Channel ID 875 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 876 877 // Signaling Packet? 878 if (channel_id == 1) { 879 880 // Get Connection 881 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 882 883 uint16_t command_offset = 8; 884 while (command_offset < size) { 885 886 // handle signaling commands 887 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 888 889 // increment command_offset 890 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 891 } 892 893 l2cap_run(); 894 895 return; 896 } 897 898 // Find channel for this channel_id and connection handle 899 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 900 if (channel) { 901 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 902 } 903 } 904 905 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 906 switch (packet_type) { 907 case HCI_EVENT_PACKET: 908 l2cap_event_handler(packet, size); 909 break; 910 case HCI_ACL_DATA_PACKET: 911 l2cap_acl_handler(packet, size); 912 break; 913 default: 914 break; 915 } 916 } 917 918 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 919 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 920 channel->state = L2CAP_STATE_CLOSED; 921 l2cap_emit_channel_closed(channel); 922 // discard channel 923 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 924 btstack_memory_l2cap_channel_free(channel); 925 } 926 927 l2cap_service_t * l2cap_get_service(uint16_t psm){ 928 linked_item_t *it; 929 930 // close open channels 931 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 932 l2cap_service_t * service = ((l2cap_service_t *) it); 933 if ( service->psm == psm){ 934 return service; 935 }; 936 } 937 return NULL; 938 } 939 940 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 941 // check for alread registered psm 942 // TODO: emit error event 943 l2cap_service_t *service = l2cap_get_service(psm); 944 if (service) { 945 log_error("l2cap_register_service_internal: PSM %u already registered\n", psm); 946 return; 947 } 948 949 // alloc structure 950 // TODO: emit error event 951 service = btstack_memory_l2cap_service_get(); 952 if (!service) { 953 log_error("l2cap_register_service_internal: no memory for l2cap_service_t\n"); 954 return; 955 } 956 957 // fill in 958 service->psm = psm; 959 service->mtu = mtu; 960 service->connection = connection; 961 service->packet_handler = packet_handler; 962 963 // add to services list 964 linked_list_add(&l2cap_services, (linked_item_t *) service); 965 } 966 967 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 968 l2cap_service_t *service = l2cap_get_service(psm); 969 if (!service) return; 970 linked_list_remove(&l2cap_services, (linked_item_t *) service); 971 btstack_memory_l2cap_service_free(service); 972 } 973 974 // 975 void l2cap_close_connection(void *connection){ 976 linked_item_t *it; 977 978 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 979 l2cap_channel_t * channel; 980 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 981 channel = (l2cap_channel_t *) it; 982 if (channel->connection == connection) { 983 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 984 } 985 } 986 987 // unregister services 988 it = (linked_item_t *) &l2cap_services; 989 while (it->next) { 990 l2cap_service_t * service = (l2cap_service_t *) it->next; 991 if (service->connection == connection){ 992 it->next = it->next->next; 993 btstack_memory_l2cap_service_free(service); 994 } else { 995 it = it->next; 996 } 997 } 998 999 // process 1000 l2cap_run(); 1001 } 1002