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