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 45 #include <stdarg.h> 46 #include <string.h> 47 48 #include <stdio.h> 49 50 // size of HCI ACL + L2CAP Header for regular data packets 51 #define COMPLETE_L2CAP_HEADER 8 52 53 // minimum signaling MTU 54 #define L2CAP_MINIMAL_MTU 48 55 #define L2CAP_DEFAULT_MTU 672 56 57 // nr of buffered acl packets in outgoing queue to get max performance 58 #define NR_BUFFERED_ACL_PACKETS 3 59 60 // used to cache l2cap rejects, echo, and informational requests 61 #define NR_PENDING_SIGNALING_RESPONSES 10 62 63 // offsets for L2CAP SIGNALING COMMANDS 64 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 65 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 66 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 67 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 68 69 typedef enum { 70 L2CAP_STATE_CLOSED = 1, // no baseband 71 L2CAP_STATE_WILL_SEND_CREATE_CONNECTION, 72 L2CAP_STATE_WAIT_CONNECTION_COMPLETE, 73 L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT, 74 L2CAP_STATE_WAIT_CONNECT_RSP, // from peer 75 L2CAP_STATE_CONFIG, 76 L2CAP_STATE_OPEN, 77 L2CAP_STATE_WAIT_DISCONNECT, // from application 78 L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST, 79 L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE, 80 L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT, 81 L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST, 82 L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE, 83 } L2CAP_STATE; 84 85 typedef enum { 86 STATE_VAR_NONE = 0, 87 STATE_VAR_RCVD_CONF_REQ = 1 << 0, 88 STATE_VAR_RCVD_CONF_RSP = 1 << 1, 89 STATE_VAR_SEND_CONF_REQ = 1 << 2, 90 STATE_VAR_SEND_CONF_RSP = 1 << 3, 91 STATE_VAR_SENT_CONF_REQ = 1 << 4, 92 STATE_VAR_SENT_CONF_RSP = 1 << 5, 93 } L2CAP_CHANNEL_STATE_VAR; 94 95 // info regarding an actual coneection 96 typedef struct { 97 // linked list - assert: first field 98 linked_item_t item; 99 100 L2CAP_STATE state; 101 L2CAP_CHANNEL_STATE_VAR state_var; 102 103 bd_addr_t address; 104 hci_con_handle_t handle; 105 106 uint8_t remote_sig_id; // used by other side, needed for delayed response 107 uint8_t local_sig_id; // own signaling identifier 108 109 uint16_t local_cid; 110 uint16_t remote_cid; 111 112 uint16_t local_mtu; 113 uint16_t remote_mtu; 114 115 uint16_t psm; 116 117 uint8_t packets_granted; // number of L2CAP/ACL packets client is allowed to send 118 119 uint8_t reason; // used in decline internal 120 121 // client connection 122 void * connection; 123 124 // internal connection 125 btstack_packet_handler_t packet_handler; 126 127 } l2cap_channel_t; 128 129 // info regarding potential connections 130 typedef struct { 131 // linked list - assert: first field 132 linked_item_t item; 133 134 // service id 135 uint16_t psm; 136 137 // incoming MTU 138 uint16_t mtu; 139 140 // client connection 141 void *connection; 142 143 // internal connection 144 btstack_packet_handler_t packet_handler; 145 146 } l2cap_service_t; 147 148 149 typedef struct l2cap_signaling_response { 150 hci_con_handle_t handle; 151 uint8_t sig_id; 152 uint8_t code; 153 uint16_t infoType; 154 } l2cap_signaling_response_t; 155 156 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 157 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 158 159 // used to cache l2cap rejects, echo, and informational requests 160 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 161 static int signaling_responses_pending; 162 163 static uint8_t * sig_buffer = NULL; 164 static linked_list_t l2cap_channels = NULL; 165 static linked_list_t l2cap_services = NULL; 166 static uint8_t * acl_buffer = NULL; 167 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 168 static int new_credits_blocked = 0; 169 170 171 // prototypes 172 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 173 static l2cap_service_t * l2cap_get_service(uint16_t psm); 174 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 175 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 176 static void l2cap_emit_connection_request(l2cap_channel_t *channel); 177 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 178 179 180 void l2cap_init(){ 181 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 182 acl_buffer = malloc( HCI_ACL_3DH5_SIZE); 183 184 new_credits_blocked = 0; 185 signaling_responses_pending = 0; 186 187 // 188 // register callback with HCI 189 // 190 hci_register_packet_handler(&l2cap_packet_handler); 191 } 192 193 194 /** Register L2CAP packet handlers */ 195 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 196 } 197 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 198 packet_handler = handler; 199 } 200 201 // notify client/protocol handler 202 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 203 if (channel->packet_handler) { 204 (* (channel->packet_handler))(type, channel->local_cid, data, size); 205 } else { 206 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 207 } 208 } 209 210 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 211 uint8_t event[21]; 212 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 213 event[1] = sizeof(event) - 2; 214 event[2] = status; 215 bt_flip_addr(&event[3], channel->address); 216 bt_store_16(event, 9, channel->handle); 217 bt_store_16(event, 11, channel->psm); 218 bt_store_16(event, 13, channel->local_cid); 219 bt_store_16(event, 15, channel->remote_cid); 220 bt_store_16(event, 17, channel->local_mtu); 221 bt_store_16(event, 19, channel->remote_mtu); 222 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 223 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 224 } 225 226 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 227 uint8_t event[4]; 228 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 229 event[1] = sizeof(event) - 2; 230 bt_store_16(event, 2, channel->local_cid); 231 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 232 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 233 } 234 235 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 236 uint8_t event[16]; 237 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 238 event[1] = sizeof(event) - 2; 239 bt_flip_addr(&event[2], channel->address); 240 bt_store_16(event, 8, channel->handle); 241 bt_store_16(event, 10, channel->psm); 242 bt_store_16(event, 12, channel->local_cid); 243 bt_store_16(event, 14, channel->remote_cid); 244 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 245 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 246 } 247 248 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 249 // track credits 250 channel->packets_granted += credits; 251 // log_info("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 252 253 uint8_t event[5]; 254 event[0] = L2CAP_EVENT_CREDITS; 255 event[1] = sizeof(event) - 2; 256 bt_store_16(event, 2, channel->local_cid); 257 event[4] = credits; 258 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 259 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 260 } 261 262 void l2cap_block_new_credits(uint8_t blocked){ 263 new_credits_blocked = blocked; 264 } 265 266 void l2cap_hand_out_credits(void){ 267 268 if (new_credits_blocked) return; // we're told not to. used by daemon 269 270 linked_item_t *it; 271 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 272 if (!hci_number_free_acl_slots()) return; 273 l2cap_channel_t * channel = (l2cap_channel_t *) it; 274 if (channel->state != L2CAP_STATE_OPEN) continue; 275 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 276 l2cap_emit_credits(channel, 1); 277 } 278 } 279 } 280 281 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 282 linked_item_t *it; 283 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 284 l2cap_channel_t * channel = (l2cap_channel_t *) it; 285 if ( channel->local_cid == local_cid) { 286 return channel; 287 } 288 } 289 return NULL; 290 } 291 292 int l2cap_can_send_packet_now(uint16_t local_cid){ 293 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 294 if (!channel) return 0; 295 if (!channel->packets_granted) return 0; 296 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 297 } 298 299 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 300 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 301 if (channel) { 302 return channel->remote_mtu; 303 } 304 return 0; 305 } 306 307 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 308 // log_info("l2cap_send_signaling_packet type %u\n", cmd); 309 va_list argptr; 310 va_start(argptr, identifier); 311 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 312 va_end(argptr); 313 // log_info("l2cap_send_signaling_packet con %u!\n", handle); 314 return hci_send_acl_packet(sig_buffer, len); 315 } 316 317 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 318 319 // check for free places on BT module 320 if (!hci_number_free_acl_slots()) { 321 log_info("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 322 return BTSTACK_ACL_BUFFERS_FULL; 323 } 324 int err = 0; 325 326 // find channel for local_cid, construct l2cap packet and send 327 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 328 if (channel) { 329 if (channel->packets_granted > 0){ 330 --channel->packets_granted; 331 // log_info("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 332 // local_cid, channel->handle, channel->packets_granted); 333 } else { 334 log_error("l2cap_send_internal cid %u, no credits!\n", local_cid); 335 } 336 337 // 0 - Connection handle : PB=10 : BC=00 338 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 339 // 2 - ACL length 340 bt_store_16(acl_buffer, 2, len + 4); 341 // 4 - L2CAP packet length 342 bt_store_16(acl_buffer, 4, len + 0); 343 // 6 - L2CAP channel DEST 344 bt_store_16(acl_buffer, 6, channel->remote_cid); 345 // 8 - data 346 memcpy(&acl_buffer[8], data, len); 347 348 // send 349 err = hci_send_acl_packet(acl_buffer, len+8); 350 } 351 352 l2cap_hand_out_credits(); 353 354 return err; 355 } 356 357 // MARK: L2CAP_RUN 358 // process outstanding signaling tasks 359 void l2cap_run(void){ 360 361 // check pending signaling responses 362 while (signaling_responses_pending){ 363 364 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 365 366 hci_con_handle_t handle = signaling_responses[0].handle; 367 uint8_t sig_id = signaling_responses[0].sig_id; 368 uint8_t infoType = signaling_responses[0].infoType; 369 370 switch (signaling_responses[0].code){ 371 case ECHO_REQUEST: 372 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 373 break; 374 case INFORMATION_REQUEST: 375 if (infoType == 2) { 376 uint32_t features = 0; 377 // extended features request supported, however no features present 378 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 379 } else { 380 // all other types are not supported 381 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 382 } 383 break; 384 default: 385 // should not happen 386 break; 387 } 388 389 // remove first item 390 signaling_responses_pending--; 391 int i; 392 for (i=0; i < signaling_responses_pending; i++){ 393 signaling_responses[i] = signaling_responses[i+1]; 394 } 395 } 396 397 uint8_t config_options[4]; 398 linked_item_t *it; 399 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 400 401 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 402 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 403 404 l2cap_channel_t * channel = (l2cap_channel_t *) it; 405 406 // log_info("l2cap_run: state %u, var 0x%02x\n", channel->state, channel->state_var); 407 408 switch (channel->state){ 409 410 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 411 // send connection request - set state first 412 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 413 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 414 hci_send_cmd(&hci_create_connection, channel->address, 0xcc18, 0, 0, 0, 1); 415 break; 416 417 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 418 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 419 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 420 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 421 free (channel); 422 break; 423 424 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 425 channel->state = L2CAP_STATE_CONFIG; 426 channel->state_var |= STATE_VAR_SEND_CONF_REQ; 427 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 428 break; 429 430 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 431 // success, start l2cap handshake 432 channel->local_sig_id = l2cap_next_sig_id(); 433 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 434 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 435 break; 436 437 case L2CAP_STATE_CONFIG: 438 if (channel->state_var & STATE_VAR_SEND_CONF_RSP){ 439 channel->state_var &= ~STATE_VAR_SEND_CONF_RSP; 440 channel->state_var |= STATE_VAR_SENT_CONF_RSP; 441 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 442 } 443 else if (channel->state_var & STATE_VAR_SEND_CONF_REQ){ 444 channel->state_var &= ~STATE_VAR_SEND_CONF_REQ; 445 channel->state_var |= STATE_VAR_SENT_CONF_REQ; 446 channel->local_sig_id = l2cap_next_sig_id(); 447 config_options[0] = 1; // MTU 448 config_options[1] = 2; // len param 449 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 450 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 451 } 452 if (l2cap_channel_ready_for_open(channel)){ 453 channel->state = L2CAP_STATE_OPEN; 454 l2cap_emit_channel_opened(channel, 0); // success 455 l2cap_emit_credits(channel, 1); 456 } 457 break; 458 459 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 460 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 461 l2cap_finialize_channel_close(channel); 462 break; 463 464 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 465 channel->local_sig_id = l2cap_next_sig_id(); 466 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 467 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 468 break; 469 default: 470 break; 471 } 472 } 473 } 474 475 static uint16_t l2cap_max_l2cap_mtu(void){ 476 return hci_max_acl_data_packet_length()-4; // 4 bytes for L2CAP header 477 } 478 479 // open outgoing L2CAP channel 480 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 481 bd_addr_t address, uint16_t psm, uint16_t mtu){ 482 483 // alloc structure 484 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 485 // TODO: emit error event 486 if (!chan) return; 487 488 // limit local mtu to max acl packet length 489 if (mtu > l2cap_max_l2cap_mtu()) { 490 mtu = l2cap_max_l2cap_mtu(); 491 } 492 493 // fill in 494 BD_ADDR_COPY(chan->address, address); 495 chan->psm = psm; 496 chan->handle = 0; 497 chan->connection = connection; 498 chan->packet_handler = packet_handler; 499 chan->remote_mtu = L2CAP_MINIMAL_MTU; 500 chan->local_mtu = mtu; 501 chan->packets_granted = 0; 502 503 // set initial state 504 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 505 chan->state_var = STATE_VAR_NONE; 506 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 507 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 508 509 // add to connections list 510 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 511 512 l2cap_run(); 513 } 514 515 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 516 // find channel for local_cid 517 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 518 if (channel) { 519 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 520 } 521 // process 522 l2cap_run(); 523 } 524 525 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 526 linked_item_t *it = (linked_item_t *) &l2cap_channels; 527 while (it->next){ 528 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 529 if ( ! BD_ADDR_CMP( channel->address, address) ){ 530 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 531 // failure, forward error code 532 l2cap_emit_channel_opened(channel, status); 533 // discard channel 534 it->next = it->next->next; 535 free (channel); 536 } 537 } else { 538 it = it->next; 539 } 540 } 541 } 542 543 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 544 linked_item_t *it; 545 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 546 l2cap_channel_t * channel = (l2cap_channel_t *) it; 547 if ( ! BD_ADDR_CMP( channel->address, address) ){ 548 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 549 // success, start l2cap handshake 550 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 551 channel->handle = handle; 552 channel->local_cid = l2cap_next_local_cid(); 553 } 554 } 555 } 556 // process 557 l2cap_run(); 558 } 559 560 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 561 562 bd_addr_t address; 563 hci_con_handle_t handle; 564 l2cap_channel_t * channel; 565 linked_item_t *it; 566 int hci_con_used; 567 568 switch(packet[0]){ 569 570 // handle connection complete events 571 case HCI_EVENT_CONNECTION_COMPLETE: 572 bt_flip_addr(address, &packet[5]); 573 if (packet[2] == 0){ 574 handle = READ_BT_16(packet, 3); 575 l2cap_handle_connection_success_for_addr(address, handle); 576 } else { 577 l2cap_handle_connection_failed_for_addr(address, packet[2]); 578 } 579 break; 580 581 // handle successful create connection cancel command 582 case HCI_EVENT_COMMAND_COMPLETE: 583 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 584 if (packet[5] == 0){ 585 bt_flip_addr(address, &packet[6]); 586 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 587 l2cap_handle_connection_failed_for_addr(address, 0x16); 588 } 589 } 590 l2cap_run(); // try sending signaling packets first 591 break; 592 593 case HCI_EVENT_COMMAND_STATUS: 594 l2cap_run(); // try sending signaling packets first 595 break; 596 597 // handle disconnection complete events 598 case HCI_EVENT_DISCONNECTION_COMPLETE: 599 // send l2cap disconnect events for all channels on this handle 600 handle = READ_BT_16(packet, 3); 601 it = (linked_item_t *) &l2cap_channels; 602 while (it->next){ 603 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 604 if ( channel->handle == handle ){ 605 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 606 it->next = it->next->next; 607 l2cap_emit_channel_closed(channel); 608 free (channel); 609 } else { 610 it = it->next; 611 } 612 } 613 break; 614 615 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 616 l2cap_run(); // try sending signaling packets first 617 l2cap_hand_out_credits(); 618 break; 619 620 // HCI Connection Timeouts 621 case L2CAP_EVENT_TIMEOUT_CHECK: 622 handle = READ_BT_16(packet, 2); 623 if (hci_authentication_active_for_handle(handle)) break; 624 hci_con_used = 0; 625 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 626 channel = (l2cap_channel_t *) it; 627 if (channel->handle == handle) { 628 hci_con_used = 1; 629 } 630 } 631 if (hci_con_used) break; 632 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 633 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 634 break; 635 636 case DAEMON_EVENT_HCI_PACKET_SENT: 637 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 638 channel = (l2cap_channel_t *) it; 639 if (channel->packet_handler) { 640 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size); 641 } 642 } 643 break; 644 645 default: 646 break; 647 } 648 649 // pass on 650 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 651 } 652 653 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 654 channel->remote_sig_id = identifier; 655 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 656 l2cap_run(); 657 } 658 659 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 660 661 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 662 l2cap_service_t *service = l2cap_get_service(psm); 663 if (!service) { 664 // 0x0002 PSM not supported 665 // log_info("l2cap_handle_connection_request no PSM for psm %u/n", psm); 666 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 667 return; 668 } 669 670 hci_connection_t * hci_connection = connection_for_handle( handle ); 671 if (!hci_connection) { 672 log_error("no hci_connection for handle %u\n", handle); 673 // TODO: emit error 674 return; 675 } 676 // alloc structure 677 // log_info("l2cap_handle_connection_request register channel\n"); 678 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 679 // TODO: emit error event 680 if (!channel) return; 681 682 // fill in 683 BD_ADDR_COPY(channel->address, hci_connection->address); 684 channel->psm = psm; 685 channel->handle = handle; 686 channel->connection = service->connection; 687 channel->packet_handler = service->packet_handler; 688 channel->local_cid = l2cap_next_local_cid(); 689 channel->remote_cid = source_cid; 690 channel->local_mtu = service->mtu; 691 channel->remote_mtu = L2CAP_DEFAULT_MTU; 692 channel->packets_granted = 0; 693 channel->remote_sig_id = sig_id; 694 695 // limit local mtu to max acl packet length 696 if (channel->local_mtu > l2cap_max_l2cap_mtu()) { 697 channel->local_mtu = l2cap_max_l2cap_mtu(); 698 } 699 700 // set initial state 701 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 702 channel->state_var = STATE_VAR_NONE; 703 704 // add to connections list 705 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 706 707 // emit incoming connection request 708 l2cap_emit_connection_request(channel); 709 } 710 711 void l2cap_accept_connection_internal(uint16_t local_cid){ 712 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 713 if (!channel) { 714 log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 715 return; 716 } 717 718 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 719 720 // process 721 l2cap_run(); 722 } 723 724 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 725 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 726 if (!channel) { 727 log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 728 return; 729 } 730 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 731 channel->reason = reason; 732 l2cap_run(); 733 } 734 735 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 736 737 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 738 739 // accept the other's configuration options 740 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 741 uint16_t pos = 8; 742 while (pos < end_pos){ 743 uint8_t type = command[pos++]; 744 uint8_t length = command[pos++]; 745 // MTU { type(8): 1, len(8):2, MTU(16) } 746 if ((type & 0x7f) == 1 && length == 2){ 747 channel->remote_mtu = READ_BT_16(command, pos); 748 // log_info("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 749 } 750 pos += length; 751 } 752 } 753 754 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 755 // log_info("l2cap_channel_ready_for_open 0x%02x\n", channel->state_var); 756 if ((channel->state_var & STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 757 if ((channel->state_var & STATE_VAR_SENT_CONF_RSP) == 0) return 0; 758 return 1; 759 } 760 761 762 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 763 764 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 765 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 766 uint16_t result = 0; 767 768 log_info("signaling handler code %u, state %u\n", code, channel->state); 769 770 // handle DISCONNECT REQUESTS seperately 771 if (code == DISCONNECTION_REQUEST){ 772 switch (channel->state){ 773 case L2CAP_STATE_CONFIG: 774 case L2CAP_STATE_OPEN: 775 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 776 case L2CAP_STATE_WAIT_DISCONNECT: 777 l2cap_handle_disconnect_request(channel, identifier); 778 break; 779 780 default: 781 // ignore in other states 782 break; 783 } 784 return; 785 } 786 787 switch (channel->state) { 788 789 case L2CAP_STATE_WAIT_CONNECT_RSP: 790 switch (code){ 791 case CONNECTION_RESPONSE: 792 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 793 switch (result) { 794 case 0: 795 // successful connection 796 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 797 channel->state = L2CAP_STATE_CONFIG; 798 channel->state_var |= STATE_VAR_SEND_CONF_REQ; 799 break; 800 case 1: 801 // connection pending. get some coffee 802 break; 803 default: 804 // channel closed 805 channel->state = L2CAP_STATE_CLOSED; 806 807 // map l2cap connection response result to BTstack status enumeration 808 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 809 810 // drop link key if security block 811 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 812 hci_drop_link_key_for_bd_addr(&channel->address); 813 } 814 815 // discard channel 816 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 817 free (channel); 818 break; 819 } 820 break; 821 822 default: 823 //@TODO: implement other signaling packets 824 break; 825 } 826 break; 827 828 case L2CAP_STATE_CONFIG: 829 switch (code) { 830 case CONFIGURE_REQUEST: 831 channel->state_var |= STATE_VAR_RCVD_CONF_REQ; 832 channel->state_var |= STATE_VAR_SEND_CONF_RSP; 833 l2cap_signaling_handle_configure_request(channel, command); 834 break; 835 case CONFIGURE_RESPONSE: 836 channel->state_var |= STATE_VAR_RCVD_CONF_RSP; 837 break; 838 default: 839 break; 840 } 841 if (l2cap_channel_ready_for_open(channel)){ 842 // for open: 843 channel->state = L2CAP_STATE_OPEN; 844 l2cap_emit_channel_opened(channel, 0); 845 l2cap_emit_credits(channel, 1); 846 } 847 break; 848 849 case L2CAP_STATE_WAIT_DISCONNECT: 850 switch (code) { 851 case DISCONNECTION_RESPONSE: 852 l2cap_finialize_channel_close(channel); 853 break; 854 default: 855 //@TODO: implement other signaling packets 856 break; 857 } 858 break; 859 860 case L2CAP_STATE_CLOSED: 861 // @TODO handle incoming requests 862 break; 863 864 case L2CAP_STATE_OPEN: 865 //@TODO: implement other signaling packets, e.g. re-configure 866 break; 867 default: 868 break; 869 } 870 // log_info("new state %u\n", channel->state); 871 } 872 873 874 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 875 876 // get code, signalind identifier and command len 877 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 878 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 879 880 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 881 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 882 return; 883 } 884 885 // general commands without an assigned channel 886 switch(code) { 887 888 case CONNECTION_REQUEST: { 889 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 890 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 891 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 892 return; 893 } 894 895 case ECHO_REQUEST: { 896 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 897 signaling_responses[signaling_responses_pending].handle = handle; 898 signaling_responses[signaling_responses_pending].code = code; 899 signaling_responses[signaling_responses_pending].sig_id = sig_id; 900 signaling_responses_pending++; 901 } 902 l2cap_run(); 903 return; 904 } 905 906 case INFORMATION_REQUEST: { 907 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 908 // we neither support connectionless L2CAP data nor support any flow control modes yet 909 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 910 signaling_responses[signaling_responses_pending].handle = handle; 911 signaling_responses[signaling_responses_pending].code = code; 912 signaling_responses[signaling_responses_pending].sig_id = sig_id; 913 signaling_responses[signaling_responses_pending].infoType = infoType; 914 signaling_responses_pending++; 915 } 916 l2cap_run(); 917 return; 918 } 919 920 default: 921 break; 922 } 923 924 925 // Get potential destination CID 926 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 927 928 // Find channel for this sig_id and connection handle 929 linked_item_t *it; 930 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 931 l2cap_channel_t * channel = (l2cap_channel_t *) it; 932 if (channel->handle == handle) { 933 if (code & 1) { 934 // match odd commands (responses) by previous signaling identifier 935 if (channel->local_sig_id == sig_id) { 936 l2cap_signaling_handler_channel(channel, command); 937 break; 938 } 939 } else { 940 // match even commands (requests) by local channel id 941 if (channel->local_cid == dest_cid) { 942 l2cap_signaling_handler_channel(channel, command); 943 break; 944 } 945 } 946 } 947 } 948 } 949 950 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 951 952 // Get Channel ID 953 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 954 955 // Signaling Packet? 956 if (channel_id == 1) { 957 958 // Get Connection 959 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 960 961 uint16_t command_offset = 8; 962 while (command_offset < size) { 963 964 // handle signaling commands 965 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 966 967 // increment command_offset 968 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 969 } 970 971 l2cap_run(); 972 973 return; 974 } 975 976 // Find channel for this channel_id and connection handle 977 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 978 if (channel) { 979 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 980 } 981 } 982 983 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 984 switch (packet_type) { 985 case HCI_EVENT_PACKET: 986 l2cap_event_handler(packet, size); 987 break; 988 case HCI_ACL_DATA_PACKET: 989 l2cap_acl_handler(packet, size); 990 break; 991 default: 992 break; 993 } 994 } 995 996 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 997 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 998 channel->state = L2CAP_STATE_CLOSED; 999 l2cap_emit_channel_closed(channel); 1000 // discard channel 1001 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 1002 free (channel); 1003 } 1004 1005 l2cap_service_t * l2cap_get_service(uint16_t psm){ 1006 linked_item_t *it; 1007 1008 // close open channels 1009 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 1010 l2cap_service_t * service = ((l2cap_service_t *) it); 1011 if ( service->psm == psm){ 1012 return service; 1013 }; 1014 } 1015 return NULL; 1016 } 1017 1018 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 1019 // check for alread registered psm // TODO: emit error event 1020 l2cap_service_t *service = l2cap_get_service(psm); 1021 if (service) return; 1022 1023 // alloc structure // TODO: emit error event 1024 service = malloc(sizeof(l2cap_service_t)); 1025 if (!service) return; 1026 1027 // fill in 1028 service->psm = psm; 1029 service->mtu = mtu; 1030 service->connection = connection; 1031 service->packet_handler = packet_handler; 1032 1033 // add to services list 1034 linked_list_add(&l2cap_services, (linked_item_t *) service); 1035 } 1036 1037 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 1038 l2cap_service_t *service = l2cap_get_service(psm); 1039 if (!service) return; 1040 linked_list_remove(&l2cap_services, (linked_item_t *) service); 1041 free(service); 1042 } 1043 1044 // 1045 void l2cap_close_connection(void *connection){ 1046 linked_item_t *it; 1047 1048 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 1049 l2cap_channel_t * channel; 1050 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 1051 channel = (l2cap_channel_t *) it; 1052 if (channel->connection == connection) { 1053 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 1054 } 1055 } 1056 1057 // unregister services 1058 it = (linked_item_t *) &l2cap_services; 1059 while (it->next) { 1060 l2cap_service_t * service = (l2cap_service_t *) it->next; 1061 if (service->connection == connection){ 1062 it->next = it->next->next; 1063 free(service); 1064 } else { 1065 it = it->next; 1066 } 1067 } 1068 1069 // process 1070 l2cap_run(); 1071 } 1072