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 // offsets for L2CAP SIGNALING COMMANDS 61 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 62 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 63 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 64 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 65 66 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 67 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size); 68 69 static uint8_t * sig_buffer = NULL; 70 static linked_list_t l2cap_channels = NULL; 71 static linked_list_t l2cap_services = NULL; 72 static uint8_t * acl_buffer = NULL; 73 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 74 static int new_credits_blocked = 0; 75 76 void l2cap_init(){ 77 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 78 acl_buffer = malloc( HCI_ACL_3DH5_SIZE); 79 80 new_credits_blocked = 0; 81 82 // 83 // register callback with HCI 84 // 85 hci_register_packet_handler(&l2cap_packet_handler); 86 } 87 88 89 /** Register L2CAP packet handlers */ 90 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 91 } 92 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 93 packet_handler = handler; 94 } 95 96 // notify client/protocol handler 97 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 98 if (channel->packet_handler) { 99 (* (channel->packet_handler))(type, channel->local_cid, data, size); 100 } else { 101 (*packet_handler)(channel->connection, type, channel->local_cid, data, size); 102 } 103 } 104 105 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 106 uint8_t event[21]; 107 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 108 event[1] = sizeof(event) - 2; 109 event[2] = status; 110 bt_flip_addr(&event[3], channel->address); 111 bt_store_16(event, 9, channel->handle); 112 bt_store_16(event, 11, channel->psm); 113 bt_store_16(event, 13, channel->local_cid); 114 bt_store_16(event, 15, channel->remote_cid); 115 bt_store_16(event, 17, channel->local_mtu); 116 bt_store_16(event, 19, channel->remote_mtu); 117 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 118 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 119 } 120 121 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 122 uint8_t event[4]; 123 event[0] = L2CAP_EVENT_CHANNEL_CLOSED; 124 event[1] = sizeof(event) - 2; 125 bt_store_16(event, 2, channel->local_cid); 126 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 127 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 128 } 129 130 void l2cap_emit_connection_request(l2cap_channel_t *channel) { 131 uint8_t event[16]; 132 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 133 event[1] = sizeof(event) - 2; 134 bt_flip_addr(&event[2], channel->address); 135 bt_store_16(event, 8, channel->handle); 136 bt_store_16(event, 10, channel->psm); 137 bt_store_16(event, 12, channel->local_cid); 138 bt_store_16(event, 14, channel->remote_cid); 139 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 140 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 141 } 142 143 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 144 // track credits 145 channel->packets_granted += credits; 146 // log_dbg("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 147 148 uint8_t event[5]; 149 event[0] = L2CAP_EVENT_CREDITS; 150 event[1] = sizeof(event) - 2; 151 bt_store_16(event, 2, channel->local_cid); 152 event[4] = credits; 153 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 154 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 155 } 156 157 void l2cap_block_new_credits(uint8_t blocked){ 158 new_credits_blocked = blocked; 159 } 160 161 void l2cap_hand_out_credits(void){ 162 163 if (new_credits_blocked) return; // we're told not to. used by daemon 164 165 linked_item_t *it; 166 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 167 if (!hci_number_free_acl_slots()) return; 168 l2cap_channel_t * channel = (l2cap_channel_t *) it; 169 if (channel->state != L2CAP_STATE_OPEN) continue; 170 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 171 l2cap_emit_credits(channel, 1); 172 } 173 } 174 } 175 176 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 177 linked_item_t *it; 178 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 179 l2cap_channel_t * channel = (l2cap_channel_t *) it; 180 if ( channel->local_cid == local_cid) { 181 return channel; 182 } 183 } 184 return NULL; 185 } 186 187 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 188 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 189 if (channel) { 190 return channel->remote_mtu; 191 } 192 return 0; 193 } 194 195 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 196 // log_dbg("l2cap_send_signaling_packet type %u\n", cmd); 197 va_list argptr; 198 va_start(argptr, identifier); 199 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 200 va_end(argptr); 201 // log_dbg("l2cap_send_signaling_packet con %u!\n", handle); 202 return hci_send_acl_packet(sig_buffer, len); 203 } 204 205 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 206 207 // check for free places on BT module 208 if (!hci_number_free_acl_slots()) { 209 log_dbg("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 210 return BTSTACK_ACL_BUFFERS_FULL; 211 } 212 int err = 0; 213 214 // find channel for local_cid, construct l2cap packet and send 215 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 216 if (channel) { 217 if (channel->packets_granted > 0){ 218 --channel->packets_granted; 219 // log_dbg("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 220 // local_cid, channel->handle, channel->packets_granted); 221 } else { 222 log_err("l2cap_send_internal cid %u, no credits!\n", local_cid); 223 } 224 225 // 0 - Connection handle : PB=10 : BC=00 226 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 227 // 2 - ACL length 228 bt_store_16(acl_buffer, 2, len + 4); 229 // 4 - L2CAP packet length 230 bt_store_16(acl_buffer, 4, len + 0); 231 // 6 - L2CAP channel DEST 232 bt_store_16(acl_buffer, 6, channel->remote_cid); 233 // 8 - data 234 memcpy(&acl_buffer[8], data, len); 235 236 // send 237 err = hci_send_acl_packet(acl_buffer, len+8); 238 } 239 240 l2cap_hand_out_credits(); 241 242 return err; 243 } 244 245 // process outstanding signaling tasks 246 void l2cap_run(void){ 247 uint8_t config_options[4]; 248 linked_item_t *it; 249 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 250 251 // can send? 252 253 l2cap_channel_t * channel = (l2cap_channel_t *) it; 254 switch (channel->state){ 255 256 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 257 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 258 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 259 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 260 free (channel); 261 break; 262 263 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 264 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 265 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 266 break; 267 268 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 269 // success, start l2cap handshake 270 channel->local_sig_id = l2cap_next_sig_id(); 271 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 272 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 273 break; 274 275 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 276 // after connection response was received 277 channel->local_sig_id = l2cap_next_sig_id(); 278 config_options[0] = 1; // MTU 279 config_options[1] = 2; // len param 280 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 281 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 282 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 283 break; 284 285 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 286 channel->local_sig_id = l2cap_next_sig_id(); 287 config_options[0] = 1; // MTU 288 config_options[1] = 2; // len param 289 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 290 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 291 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 292 break; 293 294 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 295 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 296 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 297 break; 298 299 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 300 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 301 channel->state = L2CAP_STATE_OPEN; 302 l2cap_emit_channel_opened(channel, 0); // success 303 l2cap_emit_credits(channel, 1); 304 break; 305 306 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 307 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 308 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ; 309 break; 310 311 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 312 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 313 l2cap_finialize_channel_close(channel); 314 break; 315 316 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 317 channel->local_sig_id = l2cap_next_sig_id(); 318 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 319 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 320 break; 321 default: 322 break; 323 } 324 } 325 } 326 327 // open outgoing L2CAP channel 328 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 329 bd_addr_t address, uint16_t psm, uint16_t mtu){ 330 331 // alloc structure 332 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 333 // TODO: emit error event 334 if (!chan) return; 335 336 // limit local mtu to max acl packet length 337 if (mtu > hci_max_acl_data_packet_length()) { 338 mtu = hci_max_acl_data_packet_length(); 339 } 340 341 // fill in 342 BD_ADDR_COPY(chan->address, address); 343 chan->psm = psm; 344 chan->handle = 0; 345 chan->connection = connection; 346 chan->packet_handler = packet_handler; 347 chan->remote_mtu = L2CAP_MINIMAL_MTU; 348 chan->local_mtu = mtu; 349 chan->packets_granted = 0; 350 351 // set initial state 352 chan->state = L2CAP_STATE_CLOSED; 353 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 354 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 355 356 // add to connections list 357 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 358 359 // send connection request 360 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 361 hci_send_cmd(&hci_create_connection, address, 0xcc18, 0, 0, 0, 1); 362 } 363 364 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 365 // find channel for local_cid 366 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 367 if (channel) { 368 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 369 } 370 // process 371 l2cap_run(); 372 } 373 374 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 375 linked_item_t *it = (linked_item_t *) &l2cap_channels; 376 while (it->next){ 377 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 378 if ( ! BD_ADDR_CMP( channel->address, address) ){ 379 if (channel->state == L2CAP_STATE_CLOSED) { 380 // failure, forward error code 381 l2cap_emit_channel_opened(channel, status); 382 // discard channel 383 it->next = it->next->next; 384 free (channel); 385 } 386 } else { 387 it = it->next; 388 } 389 } 390 } 391 392 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 393 linked_item_t *it; 394 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 395 l2cap_channel_t * channel = (l2cap_channel_t *) it; 396 if ( ! BD_ADDR_CMP( channel->address, address) ){ 397 if (channel->state == L2CAP_STATE_CLOSED) { 398 // success, start l2cap handshake 399 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 400 channel->handle = handle; 401 channel->local_cid = l2cap_next_local_cid(); 402 } 403 } 404 } 405 // process 406 l2cap_run(); 407 } 408 409 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 410 411 bd_addr_t address; 412 hci_con_handle_t handle; 413 linked_item_t *it; 414 415 switch(packet[0]){ 416 417 // handle connection complete events 418 case HCI_EVENT_CONNECTION_COMPLETE: 419 bt_flip_addr(address, &packet[5]); 420 if (packet[2] == 0){ 421 handle = READ_BT_16(packet, 3); 422 l2cap_handle_connection_success_for_addr(address, handle); 423 } else { 424 l2cap_handle_connection_failed_for_addr(address, packet[2]); 425 } 426 break; 427 428 // handle successful create connection cancel command 429 case HCI_EVENT_COMMAND_COMPLETE: 430 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 431 if (packet[5] == 0){ 432 bt_flip_addr(address, &packet[6]); 433 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 434 l2cap_handle_connection_failed_for_addr(address, 0x16); 435 } 436 } 437 break; 438 439 // handle disconnection complete events 440 case HCI_EVENT_DISCONNECTION_COMPLETE: 441 // send l2cap disconnect events for all channels on this handle 442 handle = READ_BT_16(packet, 3); 443 it = (linked_item_t *) &l2cap_channels; 444 while (it->next){ 445 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 446 if ( channel->handle == handle ){ 447 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 448 it->next = it->next->next; 449 l2cap_emit_channel_closed(channel); 450 free (channel); 451 } else { 452 it = it->next; 453 } 454 } 455 break; 456 457 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 458 l2cap_hand_out_credits(); 459 break; 460 461 // HCI Connection Timeouts 462 case L2CAP_EVENT_TIMEOUT_CHECK: 463 handle = READ_BT_16(packet, 2); 464 if (hci_authentication_active_for_handle(handle)) break; 465 l2cap_channel_t * channel; 466 int used = 0; 467 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 468 channel = (l2cap_channel_t *) it; 469 if (channel->handle == handle) { 470 used = 1; 471 } 472 } 473 if (!used) { 474 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 475 } 476 break; 477 478 default: 479 break; 480 } 481 482 // pass on 483 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 484 } 485 486 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 487 channel->remote_sig_id = identifier; 488 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 489 l2cap_run(); 490 } 491 492 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 493 494 // log_dbg("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 495 l2cap_service_t *service = l2cap_get_service(psm); 496 if (!service) { 497 // 0x0002 PSM not supported 498 // log_dbg("l2cap_handle_connection_request no PSM for psm %u/n", psm); 499 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 500 return; 501 } 502 503 hci_connection_t * hci_connection = connection_for_handle( handle ); 504 if (!hci_connection) { 505 log_err("no hci_connection for handle %u\n", handle); 506 // TODO: emit error 507 return; 508 } 509 // alloc structure 510 // log_dbg("l2cap_handle_connection_request register channel\n"); 511 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 512 // TODO: emit error event 513 if (!channel) return; 514 515 // fill in 516 BD_ADDR_COPY(channel->address, hci_connection->address); 517 channel->psm = psm; 518 channel->handle = handle; 519 channel->connection = service->connection; 520 channel->packet_handler = service->packet_handler; 521 channel->local_cid = l2cap_next_local_cid(); 522 channel->remote_cid = source_cid; 523 channel->local_mtu = service->mtu; 524 channel->remote_mtu = L2CAP_DEFAULT_MTU; 525 channel->packets_granted = 0; 526 channel->remote_sig_id = sig_id; 527 528 // limit local mtu to max acl packet length 529 if (channel->local_mtu > hci_max_acl_data_packet_length()) { 530 channel->local_mtu = hci_max_acl_data_packet_length(); 531 } 532 533 // set initial state 534 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 535 536 // add to connections list 537 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 538 539 // emit incoming connection request 540 l2cap_emit_connection_request(channel); 541 } 542 543 void l2cap_accept_connection_internal(uint16_t local_cid){ 544 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 545 if (!channel) { 546 log_err("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 547 return; 548 } 549 550 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 551 552 // process 553 l2cap_run(); 554 } 555 556 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 557 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 558 if (!channel) { 559 log_err( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 560 return; 561 } 562 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 563 channel->reason = reason; 564 l2cap_run(); 565 } 566 567 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 568 569 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 570 571 // accept the other's configuration options 572 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 573 uint16_t pos = 8; 574 while (pos < end_pos){ 575 uint8_t type = command[pos++]; 576 uint8_t length = command[pos++]; 577 // MTU { type(8): 1, len(8):2, MTU(16) } 578 if ((type & 0x7f) == 1 && length == 2){ 579 channel->remote_mtu = READ_BT_16(command, pos); 580 // log_dbg("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 581 } 582 pos += length; 583 } 584 } 585 586 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 587 588 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 589 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 590 uint16_t result = 0; 591 592 // log_dbg("signaling handler code %u\n", code); 593 594 // handle DISCONNECT REQUESTS seperately 595 if (code == DISCONNECTION_REQUEST){ 596 switch (channel->state){ 597 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 598 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP, 599 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 600 case L2CAP_STATE_WAIT_CONFIG_REQ: 601 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 602 case L2CAP_STATE_WILL_SEND_CONFIG_REQ, 603 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP, 604 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP, 605 case L2CAP_STATE_OPEN: 606 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST, 607 case L2CAP_STATE_WAIT_DISCONNECT: 608 l2cap_handle_disconnect_request(channel, identifier); 609 break; 610 611 default: 612 // ignore in other states 613 break; 614 } 615 return; 616 } 617 618 switch (channel->state) { 619 620 case L2CAP_STATE_WAIT_CONNECT_RSP: 621 switch (code){ 622 case CONNECTION_RESPONSE: 623 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 624 switch (result) { 625 case 0: 626 // successful connection 627 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 628 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 629 #if 0 630 channel->state = L2CAP_STATE_OPEN; 631 l2cap_emit_channel_opened(channel, 0); // success 632 l2cap_emit_credits(channel, 1); 633 #endif 634 break; 635 case 1: 636 // connection pending. get some coffee 637 break; 638 default: 639 // channel closed 640 channel->state = L2CAP_STATE_CLOSED; 641 642 // map l2cap connection response result to BTstack status enumeration 643 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 644 645 // drop link key if security block 646 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 647 hci_drop_link_key_for_bd_addr(&channel->address); 648 } 649 650 // discard channel 651 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 652 free (channel); 653 break; 654 } 655 break; 656 657 default: 658 //@TODO: implement other signaling packets 659 break; 660 } 661 break; 662 663 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 664 switch (code) { 665 case CONFIGURE_REQUEST: 666 l2cap_signaling_handle_configure_request(channel, command); 667 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP; 668 break; 669 default: 670 //@TODO: implement other signaling packets 671 break; 672 } 673 break; 674 675 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 676 switch (code) { 677 case CONFIGURE_RESPONSE: 678 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 679 break; 680 case CONFIGURE_REQUEST: 681 l2cap_signaling_handle_configure_request(channel, command); 682 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP; 683 break; 684 default: 685 //@TODO: implement other signaling packets 686 break; 687 } 688 break; 689 690 case L2CAP_STATE_WAIT_CONFIG_REQ: 691 switch (code) { 692 case CONFIGURE_REQUEST: 693 l2cap_signaling_handle_configure_request(channel, command); 694 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP; 695 break; 696 default: 697 //@TODO: implement other signaling packets 698 break; 699 } 700 break; 701 702 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 703 switch (code) { 704 case CONFIGURE_RESPONSE: 705 channel->state = L2CAP_STATE_OPEN; 706 l2cap_emit_channel_opened(channel, 0); // success 707 l2cap_emit_credits(channel, 1); 708 break; 709 default: 710 //@TODO: implement other signaling packets 711 break; 712 } 713 break; 714 715 case L2CAP_STATE_WAIT_DISCONNECT: 716 switch (code) { 717 case DISCONNECTION_RESPONSE: 718 l2cap_finialize_channel_close(channel); 719 break; 720 default: 721 //@TODO: implement other signaling packets 722 break; 723 } 724 break; 725 726 case L2CAP_STATE_CLOSED: 727 // @TODO handle incoming requests 728 break; 729 730 case L2CAP_STATE_OPEN: 731 //@TODO: implement other signaling packets, e.g. re-configure 732 break; 733 default: 734 break; 735 } 736 // log_dbg("new state %u\n", channel->state); 737 } 738 739 740 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 741 742 // get code, signalind identifier and command len 743 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 744 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 745 uint16_t len = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 746 747 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 748 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 749 return; 750 } 751 752 // general commands without an assigned channel 753 switch(code) { 754 755 case CONNECTION_REQUEST: { 756 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 757 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 758 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 759 break; 760 } 761 762 case ECHO_REQUEST: { 763 // send back packet 764 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, len, &command[L2CAP_SIGNALING_COMMAND_DATA_OFFSET]); 765 break; 766 } 767 768 case INFORMATION_REQUEST: { 769 // we neither support connectionless L2CAP data nor support any flow control modes yet 770 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 771 if (infoType == 2) { 772 uint32_t features = 0; 773 // extended features request supported, however no features present 774 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 775 } else { 776 // all other types are not supported 777 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 778 } 779 break;; 780 } 781 782 default: 783 break; 784 } 785 786 787 // Get potential destination CID 788 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 789 790 // Find channel for this sig_id and connection handle 791 linked_item_t *it; 792 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 793 l2cap_channel_t * channel = (l2cap_channel_t *) it; 794 if (channel->handle == handle) { 795 if (code & 1) { 796 // match odd commands (responses) by previous signaling identifier 797 if (channel->local_sig_id == sig_id) { 798 l2cap_signaling_handler_channel(channel, command); 799 break; 800 } 801 } else { 802 // match even commands (requests) by local channel id 803 if (channel->local_cid == dest_cid) { 804 l2cap_signaling_handler_channel(channel, command); 805 break; 806 } 807 } 808 } 809 } 810 } 811 812 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 813 814 // Get Channel ID 815 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 816 817 // Signaling Packet? 818 if (channel_id == 1) { 819 820 // Get Connection 821 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 822 823 uint16_t command_offset = 8; 824 while (command_offset < size) { 825 826 // handle signaling commands 827 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 828 829 // increment command_offset 830 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 831 } 832 return; 833 } 834 835 // Find channel for this channel_id and connection handle 836 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 837 if (channel) { 838 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 839 } 840 } 841 842 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 843 switch (packet_type) { 844 case HCI_EVENT_PACKET: 845 l2cap_event_handler(packet, size); 846 break; 847 case HCI_ACL_DATA_PACKET: 848 l2cap_acl_handler(packet, size); 849 break; 850 default: 851 break; 852 } 853 } 854 855 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 856 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 857 channel->state = L2CAP_STATE_CLOSED; 858 l2cap_emit_channel_closed(channel); 859 // discard channel 860 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 861 free (channel); 862 } 863 864 l2cap_service_t * l2cap_get_service(uint16_t psm){ 865 linked_item_t *it; 866 867 // close open channels 868 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 869 l2cap_service_t * service = ((l2cap_service_t *) it); 870 if ( service->psm == psm){ 871 return service; 872 }; 873 } 874 return NULL; 875 } 876 877 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 878 // check for alread registered psm // TODO: emit error event 879 l2cap_service_t *service = l2cap_get_service(psm); 880 if (service) return; 881 882 // alloc structure // TODO: emit error event 883 service = malloc(sizeof(l2cap_service_t)); 884 if (!service) return; 885 886 // fill in 887 service->psm = psm; 888 service->mtu = mtu; 889 service->connection = connection; 890 service->packet_handler = packet_handler; 891 892 // add to services list 893 linked_list_add(&l2cap_services, (linked_item_t *) service); 894 } 895 896 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 897 l2cap_service_t *service = l2cap_get_service(psm); 898 if (!service) return; 899 linked_list_remove(&l2cap_services, (linked_item_t *) service); 900 free(service); 901 } 902 903 // 904 void l2cap_close_connection(void *connection){ 905 linked_item_t *it; 906 907 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 908 l2cap_channel_t * channel; 909 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 910 channel = (l2cap_channel_t *) it; 911 if (channel->connection == connection) { 912 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 913 } 914 } 915 916 // unregister services 917 it = (linked_item_t *) &l2cap_services; 918 while (it->next) { 919 l2cap_service_t * service = (l2cap_service_t *) it->next; 920 if (service->connection == connection){ 921 it->next = it->next->next; 922 free(service); 923 } else { 924 it = it->next; 925 } 926 } 927 928 // process 929 l2cap_run(); 930 } 931