1 /* 2 * Copyright (C) 2009 by Matthias Ringwald 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 21 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 24 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 27 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 */ 31 32 /* 33 * l2cap.c 34 * 35 * Logical Link Control and Adaption Protocl (L2CAP) 36 * 37 * Created by Matthias Ringwald on 5/16/09. 38 */ 39 40 #include "l2cap.h" 41 #include "hci.h" 42 #include "hci_dump.h" 43 #include "debug.h" 44 #include "btstack_memory.h" 45 46 #include <stdarg.h> 47 #include <string.h> 48 49 #include <stdio.h> 50 51 // nr of buffered acl packets in outgoing queue to get max performance 52 #define NR_BUFFERED_ACL_PACKETS 3 53 54 // used to cache l2cap rejects, echo, and informational requests 55 #define NR_PENDING_SIGNALING_RESPONSES 3 56 57 // offsets for L2CAP SIGNALING COMMANDS 58 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 59 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 60 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 61 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 62 63 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 64 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 65 66 // used to cache l2cap rejects, echo, and informational requests 67 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 68 static int signaling_responses_pending; 69 70 static linked_list_t l2cap_channels = NULL; 71 static linked_list_t l2cap_services = NULL; 72 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 73 static int new_credits_blocked = 0; 74 75 // prototypes 76 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 77 static l2cap_service_t * l2cap_get_service(uint16_t psm); 78 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 79 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 80 static void l2cap_emit_connection_request(l2cap_channel_t *channel); 81 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 82 83 84 void l2cap_init(){ 85 new_credits_blocked = 0; 86 signaling_responses_pending = 0; 87 88 l2cap_channels = NULL; 89 l2cap_services = NULL; 90 91 packet_handler = null_packet_handler; 92 93 // 94 // register callback with HCI 95 // 96 hci_register_packet_handler(&l2cap_packet_handler); 97 hci_connectable_control(0); // no services yet 98 } 99 100 101 /** Register L2CAP packet handlers */ 102 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 103 } 104 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 105 packet_handler = handler; 106 } 107 108 // notify client/protocol handler 109 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 110 if (channel->packet_handler) { 111 (* (channel->packet_handler))(type, channel->local_cid, data, size); 112 } else { 113 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 114 } 115 } 116 117 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 118 uint8_t event[21]; 119 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 120 event[1] = sizeof(event) - 2; 121 event[2] = status; 122 bt_flip_addr(&event[3], channel->address); 123 bt_store_16(event, 9, channel->handle); 124 bt_store_16(event, 11, channel->psm); 125 bt_store_16(event, 13, channel->local_cid); 126 bt_store_16(event, 15, channel->remote_cid); 127 bt_store_16(event, 17, channel->local_mtu); 128 bt_store_16(event, 19, channel->remote_mtu); 129 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 130 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 131 } 132 133 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 134 uint8_t event[4]; 135 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 136 event[1] = sizeof(event) - 2; 137 bt_store_16(event, 2, channel->local_cid); 138 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 139 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 140 } 141 142 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 143 uint8_t event[16]; 144 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 145 event[1] = sizeof(event) - 2; 146 bt_flip_addr(&event[2], channel->address); 147 bt_store_16(event, 8, channel->handle); 148 bt_store_16(event, 10, channel->psm); 149 bt_store_16(event, 12, channel->local_cid); 150 bt_store_16(event, 14, channel->remote_cid); 151 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 152 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 153 } 154 155 static void l2cap_emit_service_registered(void *connection, uint8_t status, uint16_t psm){ 156 uint8_t event[5]; 157 event[0] = L2CAP_EVENT_SERVICE_REGISTERED; 158 event[1] = sizeof(event) - 2; 159 event[2] = status; 160 bt_store_16(event, 3, psm); 161 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 162 (*packet_handler)(connection, HCI_EVENT_PACKET, 0, event, sizeof(event)); 163 } 164 165 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 166 // track credits 167 channel->packets_granted += credits; 168 // log_info("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 169 170 uint8_t event[5]; 171 event[0] = L2CAP_EVENT_CREDITS; 172 event[1] = sizeof(event) - 2; 173 bt_store_16(event, 2, channel->local_cid); 174 event[4] = credits; 175 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 176 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 177 } 178 179 void l2cap_block_new_credits(uint8_t blocked){ 180 new_credits_blocked = blocked; 181 } 182 183 void l2cap_hand_out_credits(void){ 184 185 if (new_credits_blocked) return; // we're told not to. used by daemon 186 187 linked_item_t *it; 188 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 189 if (!hci_number_free_acl_slots()) return; 190 l2cap_channel_t * channel = (l2cap_channel_t *) it; 191 if (channel->state != L2CAP_STATE_OPEN) continue; 192 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 193 l2cap_emit_credits(channel, 1); 194 } 195 } 196 } 197 198 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 199 linked_item_t *it; 200 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 201 l2cap_channel_t * channel = (l2cap_channel_t *) it; 202 if ( channel->local_cid == local_cid) { 203 return channel; 204 } 205 } 206 return NULL; 207 } 208 209 int l2cap_can_send_packet_now(uint16_t local_cid){ 210 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 211 if (!channel) return 0; 212 if (!channel->packets_granted) return 0; 213 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 214 } 215 216 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 217 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 218 if (channel) { 219 return channel->remote_mtu; 220 } 221 return 0; 222 } 223 224 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 225 226 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 227 log_info("l2cap_send_signaling_packet, cannot send\n"); 228 return BTSTACK_ACL_BUFFERS_FULL; 229 } 230 231 // log_info("l2cap_send_signaling_packet type %u\n", cmd); 232 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 233 va_list argptr; 234 va_start(argptr, identifier); 235 uint16_t len = l2cap_create_signaling_internal(acl_buffer, handle, cmd, identifier, argptr); 236 va_end(argptr); 237 // log_info("l2cap_send_signaling_packet con %u!\n", handle); 238 return hci_send_acl_packet(acl_buffer, len); 239 } 240 241 uint8_t *l2cap_get_outgoing_buffer(void){ 242 return hci_get_outgoing_acl_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes 243 } 244 245 int l2cap_send_prepared(uint16_t local_cid, uint16_t len){ 246 247 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 248 log_info("l2cap_send_internal cid %u, cannot send\n", local_cid); 249 return BTSTACK_ACL_BUFFERS_FULL; 250 } 251 252 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 253 if (!channel) { 254 log_error("l2cap_send_internal no channel for cid %u\n", local_cid); 255 return -1; // TODO: define error 256 } 257 258 if (channel->packets_granted == 0){ 259 log_error("l2cap_send_internal cid %u, no credits!\n", local_cid); 260 return -1; // TODO: define error 261 } 262 263 --channel->packets_granted; 264 265 log_debug("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 266 local_cid, channel->handle, channel->packets_granted); 267 268 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 269 270 // 0 - Connection handle : PB=10 : BC=00 271 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 272 // 2 - ACL length 273 bt_store_16(acl_buffer, 2, len + 4); 274 // 4 - L2CAP packet length 275 bt_store_16(acl_buffer, 4, len + 0); 276 // 6 - L2CAP channel DEST 277 bt_store_16(acl_buffer, 6, channel->remote_cid); 278 // send 279 int err = hci_send_acl_packet(acl_buffer, len+8); 280 281 l2cap_hand_out_credits(); 282 283 return err; 284 } 285 286 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 287 288 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){ 289 log_info("l2cap_send_internal cid %u, cannot send\n", local_cid); 290 return BTSTACK_ACL_BUFFERS_FULL; 291 } 292 293 uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer(); 294 295 memcpy(&acl_buffer[8], data, len); 296 297 return l2cap_send_prepared(local_cid, len); 298 } 299 300 static inline void channelStateVarSetFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){ 301 channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var | flag); 302 } 303 304 static inline void channelStateVarClearFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){ 305 channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var & ~flag); 306 } 307 308 309 310 // MARK: L2CAP_RUN 311 // process outstanding signaling tasks 312 void l2cap_run(void){ 313 314 // check pending signaling responses 315 while (signaling_responses_pending){ 316 317 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 318 319 hci_con_handle_t handle = signaling_responses[0].handle; 320 uint8_t sig_id = signaling_responses[0].sig_id; 321 uint16_t infoType = signaling_responses[0].data; // INFORMATION_REQUEST 322 uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST 323 324 switch (signaling_responses[0].code){ 325 case CONNECTION_REQUEST: 326 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0); 327 break; 328 case ECHO_REQUEST: 329 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 330 break; 331 case INFORMATION_REQUEST: 332 if (infoType == 2) { 333 uint32_t features = 0; 334 // extended features request supported, however no features present 335 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 336 } else { 337 // all other types are not supported 338 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 339 } 340 break; 341 default: 342 // should not happen 343 break; 344 } 345 346 // remove first item 347 signaling_responses_pending--; 348 int i; 349 for (i=0; i < signaling_responses_pending; i++){ 350 memcpy(&signaling_responses[i], &signaling_responses[i+1], sizeof(l2cap_signaling_response_t)); 351 } 352 } 353 354 uint8_t config_options[4]; 355 linked_item_t *it; 356 linked_item_t *next; 357 for (it = (linked_item_t *) l2cap_channels; it ; it = next){ 358 next = it->next; // cache next item as current item might get freed 359 360 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 361 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 362 363 l2cap_channel_t * channel = (l2cap_channel_t *) it; 364 365 // log_info("l2cap_run: state %u, var 0x%02x\n", channel->state, channel->state_var); 366 367 368 switch (channel->state){ 369 370 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 371 // send connection request - set state first 372 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 373 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 374 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1); 375 break; 376 377 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 378 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 379 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 380 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); // -- remove from list 381 btstack_memory_l2cap_channel_free(channel); 382 break; 383 384 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 385 channel->state = L2CAP_STATE_CONFIG; 386 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 387 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 388 break; 389 390 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 391 // success, start l2cap handshake 392 channel->local_sig_id = l2cap_next_sig_id(); 393 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 394 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 395 break; 396 397 case L2CAP_STATE_CONFIG: 398 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 399 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 400 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 401 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 402 } 403 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 404 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 405 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ); 406 channel->local_sig_id = l2cap_next_sig_id(); 407 config_options[0] = 1; // MTU 408 config_options[1] = 2; // len param 409 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 410 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 411 } 412 if (l2cap_channel_ready_for_open(channel)){ 413 channel->state = L2CAP_STATE_OPEN; 414 l2cap_emit_channel_opened(channel, 0); // success 415 l2cap_emit_credits(channel, 1); 416 } 417 break; 418 419 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 420 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 421 l2cap_finialize_channel_close(channel); // -- remove from list 422 break; 423 424 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 425 channel->local_sig_id = l2cap_next_sig_id(); 426 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 427 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 428 break; 429 default: 430 break; 431 } 432 } 433 } 434 435 uint16_t l2cap_max_mtu(void){ 436 return hci_max_acl_data_packet_length() - L2CAP_HEADER_SIZE; 437 } 438 439 // open outgoing L2CAP channel 440 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 441 bd_addr_t address, uint16_t psm, uint16_t mtu){ 442 443 // alloc structure 444 l2cap_channel_t * chan = (l2cap_channel_t*) btstack_memory_l2cap_channel_get(); 445 if (!chan) { 446 // emit error event 447 l2cap_channel_t dummy_channel; 448 BD_ADDR_COPY(dummy_channel.address, address); 449 dummy_channel.psm = psm; 450 l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED); 451 return; 452 } 453 // limit local mtu to max acl packet length 454 if (mtu > l2cap_max_mtu()) { 455 mtu = l2cap_max_mtu(); 456 } 457 458 // fill in 459 BD_ADDR_COPY(chan->address, address); 460 chan->psm = psm; 461 chan->handle = 0; 462 chan->connection = connection; 463 chan->packet_handler = packet_handler; 464 chan->remote_mtu = L2CAP_MINIMAL_MTU; 465 chan->local_mtu = mtu; 466 chan->packets_granted = 0; 467 468 // set initial state 469 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 470 chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 471 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 472 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 473 474 // add to connections list 475 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 476 477 l2cap_run(); 478 } 479 480 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 481 // find channel for local_cid 482 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 483 if (channel) { 484 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 485 } 486 // process 487 l2cap_run(); 488 } 489 490 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 491 linked_item_t *it = (linked_item_t *) &l2cap_channels; 492 while (it->next){ 493 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 494 if ( ! BD_ADDR_CMP( channel->address, address) ){ 495 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 496 // failure, forward error code 497 l2cap_emit_channel_opened(channel, status); 498 // discard channel 499 it->next = it->next->next; 500 btstack_memory_l2cap_channel_free(channel); 501 } 502 } else { 503 it = it->next; 504 } 505 } 506 } 507 508 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 509 linked_item_t *it; 510 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 511 l2cap_channel_t * channel = (l2cap_channel_t *) it; 512 if ( ! BD_ADDR_CMP( channel->address, address) ){ 513 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 514 // success, start l2cap handshake 515 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 516 channel->handle = handle; 517 channel->local_cid = l2cap_next_local_cid(); 518 } 519 } 520 } 521 // process 522 l2cap_run(); 523 } 524 525 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 526 527 bd_addr_t address; 528 hci_con_handle_t handle; 529 l2cap_channel_t * channel; 530 linked_item_t *it; 531 int hci_con_used; 532 533 switch(packet[0]){ 534 535 // handle connection complete events 536 case HCI_EVENT_CONNECTION_COMPLETE: 537 bt_flip_addr(address, &packet[5]); 538 if (packet[2] == 0){ 539 handle = READ_BT_16(packet, 3); 540 l2cap_handle_connection_success_for_addr(address, handle); 541 } else { 542 l2cap_handle_connection_failed_for_addr(address, packet[2]); 543 } 544 break; 545 546 // handle successful create connection cancel command 547 case HCI_EVENT_COMMAND_COMPLETE: 548 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 549 if (packet[5] == 0){ 550 bt_flip_addr(address, &packet[6]); 551 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 552 l2cap_handle_connection_failed_for_addr(address, 0x16); 553 } 554 } 555 l2cap_run(); // try sending signaling packets first 556 break; 557 558 case HCI_EVENT_COMMAND_STATUS: 559 l2cap_run(); // try sending signaling packets first 560 break; 561 562 // handle disconnection complete events 563 case HCI_EVENT_DISCONNECTION_COMPLETE: 564 // send l2cap disconnect events for all channels on this handle 565 handle = READ_BT_16(packet, 3); 566 it = (linked_item_t *) &l2cap_channels; 567 while (it->next){ 568 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 569 if ( channel->handle == handle ){ 570 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 571 it->next = it->next->next; 572 l2cap_emit_channel_closed(channel); 573 btstack_memory_l2cap_channel_free(channel); 574 } else { 575 it = it->next; 576 } 577 } 578 break; 579 580 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 581 l2cap_run(); // try sending signaling packets first 582 l2cap_hand_out_credits(); 583 break; 584 585 // HCI Connection Timeouts 586 case L2CAP_EVENT_TIMEOUT_CHECK: 587 handle = READ_BT_16(packet, 2); 588 if (hci_authentication_active_for_handle(handle)) break; 589 hci_con_used = 0; 590 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 591 channel = (l2cap_channel_t *) it; 592 if (channel->handle == handle) { 593 hci_con_used = 1; 594 } 595 } 596 if (hci_con_used) break; 597 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 598 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 599 break; 600 601 case DAEMON_EVENT_HCI_PACKET_SENT: 602 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 603 channel = (l2cap_channel_t *) it; 604 if (channel->packet_handler) { 605 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size); 606 } 607 } 608 break; 609 610 default: 611 break; 612 } 613 614 // pass on 615 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 616 } 617 618 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 619 channel->remote_sig_id = identifier; 620 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 621 l2cap_run(); 622 } 623 624 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){ 625 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 626 signaling_responses[signaling_responses_pending].handle = handle; 627 signaling_responses[signaling_responses_pending].code = code; 628 signaling_responses[signaling_responses_pending].sig_id = sig_id; 629 signaling_responses[signaling_responses_pending].data = data; 630 signaling_responses_pending++; 631 l2cap_run(); 632 } 633 } 634 635 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 636 637 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 638 l2cap_service_t *service = l2cap_get_service(psm); 639 if (!service) { 640 // 0x0002 PSM not supported 641 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002); 642 return; 643 } 644 645 hci_connection_t * hci_connection = connection_for_handle( handle ); 646 if (!hci_connection) { 647 // 648 log_error("no hci_connection for handle %u\n", handle); 649 return; 650 } 651 // alloc structure 652 // log_info("l2cap_handle_connection_request register channel\n"); 653 l2cap_channel_t * channel = (l2cap_channel_t*) btstack_memory_l2cap_channel_get(); 654 if (!channel){ 655 // 0x0004 No resources available 656 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004); 657 return; 658 } 659 660 // fill in 661 BD_ADDR_COPY(channel->address, hci_connection->address); 662 channel->psm = psm; 663 channel->handle = handle; 664 channel->connection = service->connection; 665 channel->packet_handler = service->packet_handler; 666 channel->local_cid = l2cap_next_local_cid(); 667 channel->remote_cid = source_cid; 668 channel->local_mtu = service->mtu; 669 channel->remote_mtu = L2CAP_DEFAULT_MTU; 670 channel->packets_granted = 0; 671 channel->remote_sig_id = sig_id; 672 673 // limit local mtu to max acl packet length 674 if (channel->local_mtu > l2cap_max_mtu()) { 675 channel->local_mtu = l2cap_max_mtu(); 676 } 677 678 // set initial state 679 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 680 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 681 682 // add to connections list 683 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 684 685 // emit incoming connection request 686 l2cap_emit_connection_request(channel); 687 } 688 689 void l2cap_accept_connection_internal(uint16_t local_cid){ 690 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 691 if (!channel) { 692 log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 693 return; 694 } 695 696 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 697 698 // process 699 l2cap_run(); 700 } 701 702 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 703 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 704 if (!channel) { 705 log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 706 return; 707 } 708 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 709 channel->reason = reason; 710 l2cap_run(); 711 } 712 713 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 714 715 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 716 717 // accept the other's configuration options 718 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 719 uint16_t pos = 8; 720 while (pos < end_pos){ 721 uint8_t type = command[pos++]; 722 uint8_t length = command[pos++]; 723 // MTU { type(8): 1, len(8):2, MTU(16) } 724 if ((type & 0x7f) == 1 && length == 2){ 725 channel->remote_mtu = READ_BT_16(command, pos); 726 // log_info("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 727 } 728 pos += length; 729 } 730 } 731 732 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 733 // log_info("l2cap_channel_ready_for_open 0x%02x\n", channel->state_var); 734 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 735 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 736 return 1; 737 } 738 739 740 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 741 742 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 743 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 744 uint16_t result = 0; 745 746 log_info("L2CAP signaling handler code %u, state %u\n", code, channel->state); 747 748 // handle DISCONNECT REQUESTS seperately 749 if (code == DISCONNECTION_REQUEST){ 750 switch (channel->state){ 751 case L2CAP_STATE_CONFIG: 752 case L2CAP_STATE_OPEN: 753 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 754 case L2CAP_STATE_WAIT_DISCONNECT: 755 l2cap_handle_disconnect_request(channel, identifier); 756 break; 757 758 default: 759 // ignore in other states 760 break; 761 } 762 return; 763 } 764 765 // @STATEMACHINE(l2cap) 766 switch (channel->state) { 767 768 case L2CAP_STATE_WAIT_CONNECT_RSP: 769 switch (code){ 770 case CONNECTION_RESPONSE: 771 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 772 switch (result) { 773 case 0: 774 // successful connection 775 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 776 channel->state = L2CAP_STATE_CONFIG; 777 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 778 break; 779 case 1: 780 // connection pending. get some coffee 781 break; 782 default: 783 // channel closed 784 channel->state = L2CAP_STATE_CLOSED; 785 786 // map l2cap connection response result to BTstack status enumeration 787 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 788 789 // drop link key if security block 790 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 791 hci_drop_link_key_for_bd_addr(&channel->address); 792 } 793 794 // discard channel 795 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 796 btstack_memory_l2cap_channel_free(channel); 797 break; 798 } 799 break; 800 801 default: 802 //@TODO: implement other signaling packets 803 break; 804 } 805 break; 806 807 case L2CAP_STATE_CONFIG: 808 switch (code) { 809 case CONFIGURE_REQUEST: 810 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ); 811 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 812 l2cap_signaling_handle_configure_request(channel, command); 813 break; 814 case CONFIGURE_RESPONSE: 815 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP); 816 break; 817 default: 818 break; 819 } 820 if (l2cap_channel_ready_for_open(channel)){ 821 // for open: 822 channel->state = L2CAP_STATE_OPEN; 823 l2cap_emit_channel_opened(channel, 0); 824 l2cap_emit_credits(channel, 1); 825 } 826 break; 827 828 case L2CAP_STATE_WAIT_DISCONNECT: 829 switch (code) { 830 case DISCONNECTION_RESPONSE: 831 l2cap_finialize_channel_close(channel); 832 break; 833 default: 834 //@TODO: implement other signaling packets 835 break; 836 } 837 break; 838 839 case L2CAP_STATE_CLOSED: 840 // @TODO handle incoming requests 841 break; 842 843 case L2CAP_STATE_OPEN: 844 //@TODO: implement other signaling packets, e.g. re-configure 845 break; 846 default: 847 break; 848 } 849 // log_info("new state %u\n", channel->state); 850 } 851 852 853 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 854 855 // get code, signalind identifier and command len 856 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 857 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 858 859 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 860 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 861 return; 862 } 863 864 // general commands without an assigned channel 865 switch(code) { 866 867 case CONNECTION_REQUEST: { 868 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 869 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 870 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 871 return; 872 } 873 874 case ECHO_REQUEST: 875 l2cap_register_signaling_response(handle, code, sig_id, 0); 876 return; 877 878 case INFORMATION_REQUEST: { 879 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 880 l2cap_register_signaling_response(handle, code, sig_id, infoType); 881 return; 882 } 883 884 default: 885 break; 886 } 887 888 889 // Get potential destination CID 890 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 891 892 // Find channel for this sig_id and connection handle 893 linked_item_t *it; 894 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 895 l2cap_channel_t * channel = (l2cap_channel_t *) it; 896 if (channel->handle == handle) { 897 if (code & 1) { 898 // match odd commands (responses) by previous signaling identifier 899 if (channel->local_sig_id == sig_id) { 900 l2cap_signaling_handler_channel(channel, command); 901 break; 902 } 903 } else { 904 // match even commands (requests) by local channel id 905 if (channel->local_cid == dest_cid) { 906 l2cap_signaling_handler_channel(channel, command); 907 break; 908 } 909 } 910 } 911 } 912 } 913 914 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 915 916 // Get Channel ID 917 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 918 919 // Signaling Packet? 920 if (channel_id == 1) { 921 922 // Get Connection 923 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 924 925 uint16_t command_offset = 8; 926 while (command_offset < size) { 927 928 // handle signaling commands 929 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 930 931 // increment command_offset 932 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 933 } 934 935 l2cap_run(); 936 937 return; 938 } 939 940 // Find channel for this channel_id and connection handle 941 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 942 if (channel) { 943 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 944 } 945 } 946 947 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 948 switch (packet_type) { 949 case HCI_EVENT_PACKET: 950 l2cap_event_handler(packet, size); 951 break; 952 case HCI_ACL_DATA_PACKET: 953 l2cap_acl_handler(packet, size); 954 break; 955 default: 956 break; 957 } 958 } 959 960 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 961 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 962 channel->state = L2CAP_STATE_CLOSED; 963 l2cap_emit_channel_closed(channel); 964 // discard channel 965 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 966 btstack_memory_l2cap_channel_free(channel); 967 } 968 969 l2cap_service_t * l2cap_get_service(uint16_t psm){ 970 linked_item_t *it; 971 972 // close open channels 973 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 974 l2cap_service_t * service = ((l2cap_service_t *) it); 975 if ( service->psm == psm){ 976 return service; 977 }; 978 } 979 return NULL; 980 } 981 982 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 983 // check for alread registered psm 984 // TODO: emit error event 985 l2cap_service_t *service = l2cap_get_service(psm); 986 if (service) { 987 log_error("l2cap_register_service_internal: PSM %u already registered\n", psm); 988 l2cap_emit_service_registered(connection, L2CAP_SERVICE_ALREADY_REGISTERED, psm); 989 return; 990 } 991 992 // alloc structure 993 // TODO: emit error event 994 service = (l2cap_service_t *) btstack_memory_l2cap_service_get(); 995 if (!service) { 996 log_error("l2cap_register_service_internal: no memory for l2cap_service_t\n"); 997 l2cap_emit_service_registered(connection, BTSTACK_MEMORY_ALLOC_FAILED, psm); 998 return; 999 } 1000 1001 // fill in 1002 service->psm = psm; 1003 service->mtu = mtu; 1004 service->connection = connection; 1005 service->packet_handler = packet_handler; 1006 1007 // add to services list 1008 linked_list_add(&l2cap_services, (linked_item_t *) service); 1009 1010 // enable page scan 1011 hci_connectable_control(1); 1012 1013 // done 1014 l2cap_emit_service_registered(connection, 0, psm); 1015 } 1016 1017 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 1018 l2cap_service_t *service = l2cap_get_service(psm); 1019 if (!service) return; 1020 linked_list_remove(&l2cap_services, (linked_item_t *) service); 1021 btstack_memory_l2cap_service_free(service); 1022 1023 // disable page scan when no services registered 1024 if (!linked_list_empty(&l2cap_services)) return; 1025 hci_connectable_control(0); 1026 } 1027 1028 // 1029 void l2cap_close_connection(void *connection){ 1030 linked_item_t *it; 1031 1032 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 1033 l2cap_channel_t * channel; 1034 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 1035 channel = (l2cap_channel_t *) it; 1036 if (channel->connection == connection) { 1037 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 1038 } 1039 } 1040 1041 // unregister services 1042 it = (linked_item_t *) &l2cap_services; 1043 while (it->next) { 1044 l2cap_service_t * service = (l2cap_service_t *) it->next; 1045 if (service->connection == connection){ 1046 it->next = it->next->next; 1047 btstack_memory_l2cap_service_free(service); 1048 } else { 1049 it = it->next; 1050 } 1051 } 1052 1053 // process 1054 l2cap_run(); 1055 } 1056