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 // used to cache l2cap rejects, echo, and informational requests 70 #define NR_PENDING_SIGNALING_RESPONSES 10 71 typedef struct l2cap_signaling_response { 72 hci_con_handle_t handle; 73 uint8_t sig_id; 74 uint8_t code; 75 uint16_t infoType; 76 } l2cap_signaling_response_t; 77 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 78 static int signaling_responses_pending; 79 80 static uint8_t * sig_buffer = NULL; 81 static linked_list_t l2cap_channels = NULL; 82 static linked_list_t l2cap_services = NULL; 83 static uint8_t * acl_buffer = NULL; 84 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler; 85 static int new_credits_blocked = 0; 86 87 void l2cap_init(){ 88 sig_buffer = malloc( L2CAP_MINIMAL_MTU ); 89 acl_buffer = malloc( HCI_ACL_3DH5_SIZE); 90 91 new_credits_blocked = 0; 92 signaling_responses_pending = 0; 93 94 // 95 // register callback with HCI 96 // 97 hci_register_packet_handler(&l2cap_packet_handler); 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 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) { 156 // track credits 157 channel->packets_granted += credits; 158 // log_dbg("l2cap_emit_credits for cid %u, credits given: %u (+%u)\n", channel->local_cid, channel->packets_granted, credits); 159 160 uint8_t event[5]; 161 event[0] = L2CAP_EVENT_CREDITS; 162 event[1] = sizeof(event) - 2; 163 bt_store_16(event, 2, channel->local_cid); 164 event[4] = credits; 165 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 166 l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event)); 167 } 168 169 void l2cap_block_new_credits(uint8_t blocked){ 170 new_credits_blocked = blocked; 171 } 172 173 void l2cap_hand_out_credits(void){ 174 175 if (new_credits_blocked) return; // we're told not to. used by daemon 176 177 linked_item_t *it; 178 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 179 if (!hci_number_free_acl_slots()) return; 180 l2cap_channel_t * channel = (l2cap_channel_t *) it; 181 if (channel->state != L2CAP_STATE_OPEN) continue; 182 if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) { 183 l2cap_emit_credits(channel, 1); 184 } 185 } 186 } 187 188 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 189 linked_item_t *it; 190 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 191 l2cap_channel_t * channel = (l2cap_channel_t *) it; 192 if ( channel->local_cid == local_cid) { 193 return channel; 194 } 195 } 196 return NULL; 197 } 198 199 int l2cap_can_send_packet_now(uint16_t local_cid){ 200 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 201 if (!channel) return 0; 202 if (!channel->packets_granted) return 0; 203 return hci_can_send_packet_now(HCI_ACL_DATA_PACKET); 204 } 205 206 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 207 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 208 if (channel) { 209 return channel->remote_mtu; 210 } 211 return 0; 212 } 213 214 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 215 // log_dbg("l2cap_send_signaling_packet type %u\n", cmd); 216 va_list argptr; 217 va_start(argptr, identifier); 218 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 219 va_end(argptr); 220 // log_dbg("l2cap_send_signaling_packet con %u!\n", handle); 221 return hci_send_acl_packet(sig_buffer, len); 222 } 223 224 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 225 226 // check for free places on BT module 227 if (!hci_number_free_acl_slots()) { 228 log_dbg("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 229 return BTSTACK_ACL_BUFFERS_FULL; 230 } 231 int err = 0; 232 233 // find channel for local_cid, construct l2cap packet and send 234 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 235 if (channel) { 236 if (channel->packets_granted > 0){ 237 --channel->packets_granted; 238 // log_dbg("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 239 // local_cid, channel->handle, channel->packets_granted); 240 } else { 241 log_err("l2cap_send_internal cid %u, no credits!\n", local_cid); 242 } 243 244 // 0 - Connection handle : PB=10 : BC=00 245 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 246 // 2 - ACL length 247 bt_store_16(acl_buffer, 2, len + 4); 248 // 4 - L2CAP packet length 249 bt_store_16(acl_buffer, 4, len + 0); 250 // 6 - L2CAP channel DEST 251 bt_store_16(acl_buffer, 6, channel->remote_cid); 252 // 8 - data 253 memcpy(&acl_buffer[8], data, len); 254 255 // send 256 err = hci_send_acl_packet(acl_buffer, len+8); 257 } 258 259 l2cap_hand_out_credits(); 260 261 return err; 262 } 263 264 // MARK: L2CAP_RUN 265 // process outstanding signaling tasks 266 void l2cap_run(void){ 267 268 // check pending signaling responses 269 while (signaling_responses_pending){ 270 271 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 272 273 hci_con_handle_t handle = signaling_responses[0].handle; 274 uint8_t sig_id = signaling_responses[0].sig_id; 275 uint8_t infoType = signaling_responses[0].infoType; 276 277 switch (signaling_responses[0].code){ 278 case ECHO_REQUEST: 279 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 280 break; 281 case INFORMATION_REQUEST: 282 if (infoType == 2) { 283 uint32_t features = 0; 284 // extended features request supported, however no features present 285 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 286 } else { 287 // all other types are not supported 288 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 289 } 290 break; 291 default: 292 // should not happen 293 break; 294 } 295 296 // remove first item 297 signaling_responses_pending--; 298 int i; 299 for (i=0; i < signaling_responses_pending; i++){ 300 signaling_responses[i] = signaling_responses[i+1]; 301 } 302 } 303 304 uint8_t config_options[4]; 305 linked_item_t *it; 306 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 307 308 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 309 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 310 311 l2cap_channel_t * channel = (l2cap_channel_t *) it; 312 switch (channel->state){ 313 314 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 315 // send connection request - set state first 316 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 317 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 318 hci_send_cmd(&hci_create_connection, channel->address, 0xcc18, 0, 0, 0, 1); 319 break; 320 321 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 322 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 323 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 324 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 325 free (channel); 326 break; 327 328 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 329 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 330 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 331 break; 332 333 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 334 // success, start l2cap handshake 335 channel->local_sig_id = l2cap_next_sig_id(); 336 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 337 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 338 break; 339 340 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 341 // after connection response was received 342 channel->local_sig_id = l2cap_next_sig_id(); 343 config_options[0] = 1; // MTU 344 config_options[1] = 2; // len param 345 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 346 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 347 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 348 break; 349 350 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 351 channel->local_sig_id = l2cap_next_sig_id(); 352 config_options[0] = 1; // MTU 353 config_options[1] = 2; // len param 354 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 355 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 356 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 357 break; 358 359 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 360 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 361 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 362 break; 363 364 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 365 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 366 channel->state = L2CAP_STATE_OPEN; 367 l2cap_emit_channel_opened(channel, 0); // success 368 l2cap_emit_credits(channel, 1); 369 break; 370 371 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 372 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 373 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ; 374 break; 375 376 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 377 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 378 l2cap_finialize_channel_close(channel); 379 break; 380 381 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 382 channel->local_sig_id = l2cap_next_sig_id(); 383 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 384 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 385 break; 386 default: 387 break; 388 } 389 } 390 } 391 392 static uint16_t l2cap_max_l2cap_mtu(void){ 393 return hci_max_acl_data_packet_length()-4; // 4 bytes for L2CAP header 394 } 395 396 // open outgoing L2CAP channel 397 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 398 bd_addr_t address, uint16_t psm, uint16_t mtu){ 399 400 // alloc structure 401 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 402 // TODO: emit error event 403 if (!chan) return; 404 405 // limit local mtu to max acl packet length 406 if (mtu > l2cap_max_l2cap_mtu()) { 407 mtu = l2cap_max_l2cap_mtu(); 408 } 409 410 // fill in 411 BD_ADDR_COPY(chan->address, address); 412 chan->psm = psm; 413 chan->handle = 0; 414 chan->connection = connection; 415 chan->packet_handler = packet_handler; 416 chan->remote_mtu = L2CAP_MINIMAL_MTU; 417 chan->local_mtu = mtu; 418 chan->packets_granted = 0; 419 420 // set initial state 421 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 422 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 423 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 424 425 // add to connections list 426 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 427 428 l2cap_run(); 429 } 430 431 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 432 // find channel for local_cid 433 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 434 if (channel) { 435 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 436 } 437 // process 438 l2cap_run(); 439 } 440 441 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 442 linked_item_t *it = (linked_item_t *) &l2cap_channels; 443 while (it->next){ 444 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 445 if ( ! BD_ADDR_CMP( channel->address, address) ){ 446 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 447 // failure, forward error code 448 l2cap_emit_channel_opened(channel, status); 449 // discard channel 450 it->next = it->next->next; 451 free (channel); 452 } 453 } else { 454 it = it->next; 455 } 456 } 457 } 458 459 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 460 linked_item_t *it; 461 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 462 l2cap_channel_t * channel = (l2cap_channel_t *) it; 463 if ( ! BD_ADDR_CMP( channel->address, address) ){ 464 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 465 // success, start l2cap handshake 466 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 467 channel->handle = handle; 468 channel->local_cid = l2cap_next_local_cid(); 469 } 470 } 471 } 472 // process 473 l2cap_run(); 474 } 475 476 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 477 478 bd_addr_t address; 479 hci_con_handle_t handle; 480 linked_item_t *it; 481 482 switch(packet[0]){ 483 484 // handle connection complete events 485 case HCI_EVENT_CONNECTION_COMPLETE: 486 bt_flip_addr(address, &packet[5]); 487 if (packet[2] == 0){ 488 handle = READ_BT_16(packet, 3); 489 l2cap_handle_connection_success_for_addr(address, handle); 490 } else { 491 l2cap_handle_connection_failed_for_addr(address, packet[2]); 492 } 493 break; 494 495 // handle successful create connection cancel command 496 case HCI_EVENT_COMMAND_COMPLETE: 497 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 498 if (packet[5] == 0){ 499 bt_flip_addr(address, &packet[6]); 500 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 501 l2cap_handle_connection_failed_for_addr(address, 0x16); 502 } 503 } 504 l2cap_run(); // try sending signaling packets first 505 break; 506 507 case HCI_EVENT_COMMAND_STATUS: 508 l2cap_run(); // try sending signaling packets first 509 break; 510 511 // handle disconnection complete events 512 case HCI_EVENT_DISCONNECTION_COMPLETE: 513 // send l2cap disconnect events for all channels on this handle 514 handle = READ_BT_16(packet, 3); 515 it = (linked_item_t *) &l2cap_channels; 516 while (it->next){ 517 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 518 if ( channel->handle == handle ){ 519 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 520 it->next = it->next->next; 521 l2cap_emit_channel_closed(channel); 522 free (channel); 523 } else { 524 it = it->next; 525 } 526 } 527 break; 528 529 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 530 l2cap_run(); // try sending signaling packets first 531 l2cap_hand_out_credits(); 532 break; 533 534 // HCI Connection Timeouts 535 case L2CAP_EVENT_TIMEOUT_CHECK: 536 handle = READ_BT_16(packet, 2); 537 if (hci_authentication_active_for_handle(handle)) break; 538 l2cap_channel_t * channel; 539 int used = 0; 540 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 541 channel = (l2cap_channel_t *) it; 542 if (channel->handle == handle) { 543 used = 1; 544 } 545 } 546 if (used) break; 547 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 548 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 549 break; 550 551 default: 552 break; 553 } 554 555 // pass on 556 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 557 } 558 559 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 560 channel->remote_sig_id = identifier; 561 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 562 l2cap_run(); 563 } 564 565 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 566 567 // log_dbg("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 568 l2cap_service_t *service = l2cap_get_service(psm); 569 if (!service) { 570 // 0x0002 PSM not supported 571 // log_dbg("l2cap_handle_connection_request no PSM for psm %u/n", psm); 572 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 573 return; 574 } 575 576 hci_connection_t * hci_connection = connection_for_handle( handle ); 577 if (!hci_connection) { 578 log_err("no hci_connection for handle %u\n", handle); 579 // TODO: emit error 580 return; 581 } 582 // alloc structure 583 // log_dbg("l2cap_handle_connection_request register channel\n"); 584 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 585 // TODO: emit error event 586 if (!channel) return; 587 588 // fill in 589 BD_ADDR_COPY(channel->address, hci_connection->address); 590 channel->psm = psm; 591 channel->handle = handle; 592 channel->connection = service->connection; 593 channel->packet_handler = service->packet_handler; 594 channel->local_cid = l2cap_next_local_cid(); 595 channel->remote_cid = source_cid; 596 channel->local_mtu = service->mtu; 597 channel->remote_mtu = L2CAP_DEFAULT_MTU; 598 channel->packets_granted = 0; 599 channel->remote_sig_id = sig_id; 600 601 // limit local mtu to max acl packet length 602 if (channel->local_mtu > l2cap_max_l2cap_mtu()) { 603 channel->local_mtu = l2cap_max_l2cap_mtu(); 604 } 605 606 // set initial state 607 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 608 609 // add to connections list 610 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 611 612 // emit incoming connection request 613 l2cap_emit_connection_request(channel); 614 } 615 616 void l2cap_accept_connection_internal(uint16_t local_cid){ 617 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 618 if (!channel) { 619 log_err("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 620 return; 621 } 622 623 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 624 625 // process 626 l2cap_run(); 627 } 628 629 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 630 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 631 if (!channel) { 632 log_err( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 633 return; 634 } 635 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 636 channel->reason = reason; 637 l2cap_run(); 638 } 639 640 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 641 642 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 643 644 // accept the other's configuration options 645 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 646 uint16_t pos = 8; 647 while (pos < end_pos){ 648 uint8_t type = command[pos++]; 649 uint8_t length = command[pos++]; 650 // MTU { type(8): 1, len(8):2, MTU(16) } 651 if ((type & 0x7f) == 1 && length == 2){ 652 channel->remote_mtu = READ_BT_16(command, pos); 653 // log_dbg("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 654 } 655 pos += length; 656 } 657 } 658 659 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 660 661 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 662 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 663 uint16_t result = 0; 664 665 log_dbg("signaling handler code %u, state %u\n", code, channel->state); 666 667 // handle DISCONNECT REQUESTS seperately 668 if (code == DISCONNECTION_REQUEST){ 669 switch (channel->state){ 670 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 671 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 672 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 673 case L2CAP_STATE_WAIT_CONFIG_REQ: 674 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 675 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 676 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 677 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 678 case L2CAP_STATE_OPEN: 679 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 680 case L2CAP_STATE_WAIT_DISCONNECT: 681 l2cap_handle_disconnect_request(channel, identifier); 682 break; 683 684 default: 685 // ignore in other states 686 break; 687 } 688 return; 689 } 690 691 switch (channel->state) { 692 693 case L2CAP_STATE_WAIT_CONNECT_RSP: 694 switch (code){ 695 case CONNECTION_RESPONSE: 696 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 697 switch (result) { 698 case 0: 699 // successful connection 700 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 701 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 702 #if 0 703 channel->state = L2CAP_STATE_OPEN; 704 l2cap_emit_channel_opened(channel, 0); // success 705 l2cap_emit_credits(channel, 1); 706 #endif 707 break; 708 case 1: 709 // connection pending. get some coffee 710 break; 711 default: 712 // channel closed 713 channel->state = L2CAP_STATE_CLOSED; 714 715 // map l2cap connection response result to BTstack status enumeration 716 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 717 718 // drop link key if security block 719 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 720 hci_drop_link_key_for_bd_addr(&channel->address); 721 } 722 723 // discard channel 724 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 725 free (channel); 726 break; 727 } 728 break; 729 730 default: 731 //@TODO: implement other signaling packets 732 break; 733 } 734 break; 735 736 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 737 switch (code) { 738 case CONFIGURE_REQUEST: 739 l2cap_signaling_handle_configure_request(channel, command); 740 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP; 741 break; 742 default: 743 //@TODO: implement other signaling packets 744 break; 745 } 746 break; 747 748 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 749 switch (code) { 750 case CONFIGURE_RESPONSE: 751 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 752 break; 753 case CONFIGURE_REQUEST: 754 l2cap_signaling_handle_configure_request(channel, command); 755 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP; 756 break; 757 default: 758 //@TODO: implement other signaling packets 759 break; 760 } 761 break; 762 763 case L2CAP_STATE_WAIT_CONFIG_REQ: 764 switch (code) { 765 case CONFIGURE_REQUEST: 766 l2cap_signaling_handle_configure_request(channel, command); 767 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP; 768 break; 769 default: 770 //@TODO: implement other signaling packets 771 break; 772 } 773 break; 774 775 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 776 switch (code) { 777 case CONFIGURE_RESPONSE: 778 channel->state = L2CAP_STATE_OPEN; 779 l2cap_emit_channel_opened(channel, 0); // success 780 l2cap_emit_credits(channel, 1); 781 break; 782 default: 783 //@TODO: implement other signaling packets 784 break; 785 } 786 break; 787 788 case L2CAP_STATE_WAIT_DISCONNECT: 789 switch (code) { 790 case DISCONNECTION_RESPONSE: 791 l2cap_finialize_channel_close(channel); 792 break; 793 default: 794 //@TODO: implement other signaling packets 795 break; 796 } 797 break; 798 799 case L2CAP_STATE_CLOSED: 800 // @TODO handle incoming requests 801 break; 802 803 case L2CAP_STATE_OPEN: 804 //@TODO: implement other signaling packets, e.g. re-configure 805 break; 806 default: 807 break; 808 } 809 // log_dbg("new state %u\n", channel->state); 810 } 811 812 813 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 814 815 // get code, signalind identifier and command len 816 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 817 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 818 819 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 820 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 821 return; 822 } 823 824 // general commands without an assigned channel 825 switch(code) { 826 827 case CONNECTION_REQUEST: { 828 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 829 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 830 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 831 return; 832 } 833 834 case ECHO_REQUEST: { 835 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 836 signaling_responses[signaling_responses_pending].handle = handle; 837 signaling_responses[signaling_responses_pending].code = code; 838 signaling_responses[signaling_responses_pending].sig_id = sig_id; 839 signaling_responses_pending++; 840 } 841 l2cap_run(); 842 return; 843 } 844 845 case INFORMATION_REQUEST: { 846 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 847 // we neither support connectionless L2CAP data nor support any flow control modes yet 848 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 849 signaling_responses[signaling_responses_pending].handle = handle; 850 signaling_responses[signaling_responses_pending].code = code; 851 signaling_responses[signaling_responses_pending].sig_id = sig_id; 852 signaling_responses[signaling_responses_pending].infoType = infoType; 853 signaling_responses_pending++; 854 } 855 l2cap_run(); 856 return; 857 } 858 859 default: 860 break; 861 } 862 863 864 // Get potential destination CID 865 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 866 867 // Find channel for this sig_id and connection handle 868 linked_item_t *it; 869 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 870 l2cap_channel_t * channel = (l2cap_channel_t *) it; 871 if (channel->handle == handle) { 872 if (code & 1) { 873 // match odd commands (responses) by previous signaling identifier 874 if (channel->local_sig_id == sig_id) { 875 l2cap_signaling_handler_channel(channel, command); 876 break; 877 } 878 } else { 879 // match even commands (requests) by local channel id 880 if (channel->local_cid == dest_cid) { 881 l2cap_signaling_handler_channel(channel, command); 882 break; 883 } 884 } 885 } 886 } 887 } 888 889 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 890 891 // Get Channel ID 892 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 893 894 // Signaling Packet? 895 if (channel_id == 1) { 896 897 // Get Connection 898 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 899 900 uint16_t command_offset = 8; 901 while (command_offset < size) { 902 903 // handle signaling commands 904 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 905 906 // increment command_offset 907 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 908 } 909 910 l2cap_run(); 911 912 return; 913 } 914 915 // Find channel for this channel_id and connection handle 916 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 917 if (channel) { 918 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 919 } 920 } 921 922 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 923 switch (packet_type) { 924 case HCI_EVENT_PACKET: 925 l2cap_event_handler(packet, size); 926 break; 927 case HCI_ACL_DATA_PACKET: 928 l2cap_acl_handler(packet, size); 929 break; 930 default: 931 break; 932 } 933 } 934 935 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 936 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 937 channel->state = L2CAP_STATE_CLOSED; 938 l2cap_emit_channel_closed(channel); 939 // discard channel 940 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 941 free (channel); 942 } 943 944 l2cap_service_t * l2cap_get_service(uint16_t psm){ 945 linked_item_t *it; 946 947 // close open channels 948 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 949 l2cap_service_t * service = ((l2cap_service_t *) it); 950 if ( service->psm == psm){ 951 return service; 952 }; 953 } 954 return NULL; 955 } 956 957 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 958 // check for alread registered psm // TODO: emit error event 959 l2cap_service_t *service = l2cap_get_service(psm); 960 if (service) return; 961 962 // alloc structure // TODO: emit error event 963 service = malloc(sizeof(l2cap_service_t)); 964 if (!service) return; 965 966 // fill in 967 service->psm = psm; 968 service->mtu = mtu; 969 service->connection = connection; 970 service->packet_handler = packet_handler; 971 972 // add to services list 973 linked_list_add(&l2cap_services, (linked_item_t *) service); 974 } 975 976 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 977 l2cap_service_t *service = l2cap_get_service(psm); 978 if (!service) return; 979 linked_list_remove(&l2cap_services, (linked_item_t *) service); 980 free(service); 981 } 982 983 // 984 void l2cap_close_connection(void *connection){ 985 linked_item_t *it; 986 987 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 988 l2cap_channel_t * channel; 989 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 990 channel = (l2cap_channel_t *) it; 991 if (channel->connection == connection) { 992 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 993 } 994 } 995 996 // unregister services 997 it = (linked_item_t *) &l2cap_services; 998 while (it->next) { 999 l2cap_service_t * service = (l2cap_service_t *) it->next; 1000 if (service->connection == connection){ 1001 it->next = it->next->next; 1002 free(service); 1003 } else { 1004 it = it->next; 1005 } 1006 } 1007 1008 // process 1009 l2cap_run(); 1010 } 1011