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 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 200 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 201 if (channel) { 202 return channel->remote_mtu; 203 } 204 return 0; 205 } 206 207 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 208 // log_dbg("l2cap_send_signaling_packet type %u\n", cmd); 209 va_list argptr; 210 va_start(argptr, identifier); 211 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 212 va_end(argptr); 213 // log_dbg("l2cap_send_signaling_packet con %u!\n", handle); 214 return hci_send_acl_packet(sig_buffer, len); 215 } 216 217 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){ 218 219 // check for free places on BT module 220 if (!hci_number_free_acl_slots()) { 221 log_dbg("l2cap_send_internal cid %u, BT module full <-----\n", local_cid); 222 return BTSTACK_ACL_BUFFERS_FULL; 223 } 224 int err = 0; 225 226 // find channel for local_cid, construct l2cap packet and send 227 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 228 if (channel) { 229 if (channel->packets_granted > 0){ 230 --channel->packets_granted; 231 // log_dbg("l2cap_send_internal cid %u, handle %u, 1 credit used, credits left %u;\n", 232 // local_cid, channel->handle, channel->packets_granted); 233 } else { 234 log_err("l2cap_send_internal cid %u, no credits!\n", local_cid); 235 } 236 237 // 0 - Connection handle : PB=10 : BC=00 238 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 239 // 2 - ACL length 240 bt_store_16(acl_buffer, 2, len + 4); 241 // 4 - L2CAP packet length 242 bt_store_16(acl_buffer, 4, len + 0); 243 // 6 - L2CAP channel DEST 244 bt_store_16(acl_buffer, 6, channel->remote_cid); 245 // 8 - data 246 memcpy(&acl_buffer[8], data, len); 247 248 // send 249 err = hci_send_acl_packet(acl_buffer, len+8); 250 } 251 252 l2cap_hand_out_credits(); 253 254 return err; 255 } 256 257 // process outstanding signaling tasks 258 void l2cap_run(void){ 259 260 261 // check pending signaling responses 262 while (signaling_responses_pending){ 263 264 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 265 266 hci_con_handle_t handle = signaling_responses[0].handle; 267 uint8_t sig_id = signaling_responses[0].sig_id; 268 uint8_t infoType = signaling_responses[0].infoType; 269 270 switch (signaling_responses[0].code){ 271 case ECHO_REQUEST: 272 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 273 break; 274 case INFORMATION_REQUEST: 275 if (infoType == 2) { 276 uint32_t features = 0; 277 // extended features request supported, however no features present 278 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, 4, &features); 279 } else { 280 // all other types are not supported 281 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL); 282 } 283 break; 284 default: 285 // should not happen 286 break; 287 } 288 289 // remove first item 290 signaling_responses_pending--; 291 int i; 292 for (i=0; i < signaling_responses_pending; i++){ 293 signaling_responses[i] = signaling_responses[i+1]; 294 } 295 } 296 297 uint8_t config_options[4]; 298 linked_item_t *it; 299 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 300 301 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 302 if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)) break; 303 304 l2cap_channel_t * channel = (l2cap_channel_t *) it; 305 switch (channel->state){ 306 307 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 308 // send connection request 309 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 310 hci_send_cmd(&hci_create_connection, channel->address, 0xcc18, 0, 0, 0, 1); 311 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 312 break; 313 314 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 315 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, channel->reason, 0); 316 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 317 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 318 free (channel); 319 break; 320 321 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 322 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 323 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 324 break; 325 326 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 327 // success, start l2cap handshake 328 channel->local_sig_id = l2cap_next_sig_id(); 329 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 330 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 331 break; 332 333 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 334 // after connection response was received 335 channel->local_sig_id = l2cap_next_sig_id(); 336 config_options[0] = 1; // MTU 337 config_options[1] = 2; // len param 338 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 339 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 340 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ; 341 break; 342 343 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 344 channel->local_sig_id = l2cap_next_sig_id(); 345 config_options[0] = 1; // MTU 346 config_options[1] = 2; // len param 347 bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu); 348 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options); 349 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 350 break; 351 352 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 353 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 354 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 355 break; 356 357 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 358 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, 0, 0, 0, NULL); 359 channel->state = L2CAP_STATE_OPEN; 360 l2cap_emit_channel_opened(channel, 0); // success 361 l2cap_emit_credits(channel, 1); 362 break; 363 364 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_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_WILL_SEND_CONFIG_REQ; 367 break; 368 369 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 370 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 371 l2cap_finialize_channel_close(channel); 372 break; 373 374 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 375 channel->local_sig_id = l2cap_next_sig_id(); 376 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 377 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 378 break; 379 default: 380 break; 381 } 382 } 383 } 384 385 // open outgoing L2CAP channel 386 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 387 bd_addr_t address, uint16_t psm, uint16_t mtu){ 388 389 // alloc structure 390 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 391 // TODO: emit error event 392 if (!chan) return; 393 394 // limit local mtu to max acl packet length 395 if (mtu > hci_max_acl_data_packet_length()) { 396 mtu = hci_max_acl_data_packet_length(); 397 } 398 399 // fill in 400 BD_ADDR_COPY(chan->address, address); 401 chan->psm = psm; 402 chan->handle = 0; 403 chan->connection = connection; 404 chan->packet_handler = packet_handler; 405 chan->remote_mtu = L2CAP_MINIMAL_MTU; 406 chan->local_mtu = mtu; 407 chan->packets_granted = 0; 408 409 // set initial state 410 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 411 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 412 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 413 414 // add to connections list 415 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 416 417 l2cap_run(); 418 } 419 420 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 421 // find channel for local_cid 422 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 423 if (channel) { 424 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 425 } 426 // process 427 l2cap_run(); 428 } 429 430 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 431 linked_item_t *it = (linked_item_t *) &l2cap_channels; 432 while (it->next){ 433 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 434 if ( ! BD_ADDR_CMP( channel->address, address) ){ 435 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 436 // failure, forward error code 437 l2cap_emit_channel_opened(channel, status); 438 // discard channel 439 it->next = it->next->next; 440 free (channel); 441 } 442 } else { 443 it = it->next; 444 } 445 } 446 } 447 448 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 449 linked_item_t *it; 450 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 451 l2cap_channel_t * channel = (l2cap_channel_t *) it; 452 if ( ! BD_ADDR_CMP( channel->address, address) ){ 453 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 454 // success, start l2cap handshake 455 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 456 channel->handle = handle; 457 channel->local_cid = l2cap_next_local_cid(); 458 } 459 } 460 } 461 // process 462 l2cap_run(); 463 } 464 465 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 466 467 bd_addr_t address; 468 hci_con_handle_t handle; 469 linked_item_t *it; 470 471 switch(packet[0]){ 472 473 // handle connection complete events 474 case HCI_EVENT_CONNECTION_COMPLETE: 475 bt_flip_addr(address, &packet[5]); 476 if (packet[2] == 0){ 477 handle = READ_BT_16(packet, 3); 478 l2cap_handle_connection_success_for_addr(address, handle); 479 } else { 480 l2cap_handle_connection_failed_for_addr(address, packet[2]); 481 } 482 break; 483 484 // handle successful create connection cancel command 485 case HCI_EVENT_COMMAND_COMPLETE: 486 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 487 if (packet[5] == 0){ 488 bt_flip_addr(address, &packet[6]); 489 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 490 l2cap_handle_connection_failed_for_addr(address, 0x16); 491 } 492 } 493 break; 494 495 // handle disconnection complete events 496 case HCI_EVENT_DISCONNECTION_COMPLETE: 497 // send l2cap disconnect events for all channels on this handle 498 handle = READ_BT_16(packet, 3); 499 it = (linked_item_t *) &l2cap_channels; 500 while (it->next){ 501 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 502 if ( channel->handle == handle ){ 503 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 504 it->next = it->next->next; 505 l2cap_emit_channel_closed(channel); 506 free (channel); 507 } else { 508 it = it->next; 509 } 510 } 511 break; 512 513 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 514 l2cap_run(); // try sending signaling packets first 515 l2cap_hand_out_credits(); 516 break; 517 518 // HCI Connection Timeouts 519 case L2CAP_EVENT_TIMEOUT_CHECK: 520 handle = READ_BT_16(packet, 2); 521 if (hci_authentication_active_for_handle(handle)) break; 522 l2cap_channel_t * channel; 523 int used = 0; 524 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 525 channel = (l2cap_channel_t *) it; 526 if (channel->handle == handle) { 527 used = 1; 528 } 529 } 530 if (used) break; 531 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 532 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 533 break; 534 535 default: 536 break; 537 } 538 539 // pass on 540 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 541 } 542 543 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 544 channel->remote_sig_id = identifier; 545 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 546 l2cap_run(); 547 } 548 549 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 550 551 // log_dbg("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 552 l2cap_service_t *service = l2cap_get_service(psm); 553 if (!service) { 554 // 0x0002 PSM not supported 555 // log_dbg("l2cap_handle_connection_request no PSM for psm %u/n", psm); 556 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 557 return; 558 } 559 560 hci_connection_t * hci_connection = connection_for_handle( handle ); 561 if (!hci_connection) { 562 log_err("no hci_connection for handle %u\n", handle); 563 // TODO: emit error 564 return; 565 } 566 // alloc structure 567 // log_dbg("l2cap_handle_connection_request register channel\n"); 568 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 569 // TODO: emit error event 570 if (!channel) return; 571 572 // fill in 573 BD_ADDR_COPY(channel->address, hci_connection->address); 574 channel->psm = psm; 575 channel->handle = handle; 576 channel->connection = service->connection; 577 channel->packet_handler = service->packet_handler; 578 channel->local_cid = l2cap_next_local_cid(); 579 channel->remote_cid = source_cid; 580 channel->local_mtu = service->mtu; 581 channel->remote_mtu = L2CAP_DEFAULT_MTU; 582 channel->packets_granted = 0; 583 channel->remote_sig_id = sig_id; 584 585 // limit local mtu to max acl packet length 586 if (channel->local_mtu > hci_max_acl_data_packet_length()) { 587 channel->local_mtu = hci_max_acl_data_packet_length(); 588 } 589 590 // set initial state 591 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 592 593 // add to connections list 594 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 595 596 // emit incoming connection request 597 l2cap_emit_connection_request(channel); 598 } 599 600 void l2cap_accept_connection_internal(uint16_t local_cid){ 601 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 602 if (!channel) { 603 log_err("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 604 return; 605 } 606 607 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 608 609 // process 610 l2cap_run(); 611 } 612 613 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 614 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 615 if (!channel) { 616 log_err( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 617 return; 618 } 619 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 620 channel->reason = reason; 621 l2cap_run(); 622 } 623 624 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 625 626 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 627 628 // accept the other's configuration options 629 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 630 uint16_t pos = 8; 631 while (pos < end_pos){ 632 uint8_t type = command[pos++]; 633 uint8_t length = command[pos++]; 634 // MTU { type(8): 1, len(8):2, MTU(16) } 635 if ((type & 0x7f) == 1 && length == 2){ 636 channel->remote_mtu = READ_BT_16(command, pos); 637 // log_dbg("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 638 } 639 pos += length; 640 } 641 } 642 643 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 644 645 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 646 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 647 uint16_t result = 0; 648 649 // log_dbg("signaling handler code %u\n", code); 650 651 // handle DISCONNECT REQUESTS seperately 652 if (code == DISCONNECTION_REQUEST){ 653 switch (channel->state){ 654 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 655 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 656 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 657 case L2CAP_STATE_WAIT_CONFIG_REQ: 658 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 659 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 660 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 661 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 662 case L2CAP_STATE_OPEN: 663 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 664 case L2CAP_STATE_WAIT_DISCONNECT: 665 l2cap_handle_disconnect_request(channel, identifier); 666 break; 667 668 default: 669 // ignore in other states 670 break; 671 } 672 return; 673 } 674 675 switch (channel->state) { 676 677 case L2CAP_STATE_WAIT_CONNECT_RSP: 678 switch (code){ 679 case CONNECTION_RESPONSE: 680 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 681 switch (result) { 682 case 0: 683 // successful connection 684 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 685 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 686 #if 0 687 channel->state = L2CAP_STATE_OPEN; 688 l2cap_emit_channel_opened(channel, 0); // success 689 l2cap_emit_credits(channel, 1); 690 #endif 691 break; 692 case 1: 693 // connection pending. get some coffee 694 break; 695 default: 696 // channel closed 697 channel->state = L2CAP_STATE_CLOSED; 698 699 // map l2cap connection response result to BTstack status enumeration 700 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 701 702 // drop link key if security block 703 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 704 hci_drop_link_key_for_bd_addr(&channel->address); 705 } 706 707 // discard channel 708 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 709 free (channel); 710 break; 711 } 712 break; 713 714 default: 715 //@TODO: implement other signaling packets 716 break; 717 } 718 break; 719 720 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 721 switch (code) { 722 case CONFIGURE_REQUEST: 723 l2cap_signaling_handle_configure_request(channel, command); 724 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP; 725 break; 726 default: 727 //@TODO: implement other signaling packets 728 break; 729 } 730 break; 731 732 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 733 switch (code) { 734 case CONFIGURE_RESPONSE: 735 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 736 break; 737 case CONFIGURE_REQUEST: 738 l2cap_signaling_handle_configure_request(channel, command); 739 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP; 740 break; 741 default: 742 //@TODO: implement other signaling packets 743 break; 744 } 745 break; 746 747 case L2CAP_STATE_WAIT_CONFIG_REQ: 748 switch (code) { 749 case CONFIGURE_REQUEST: 750 l2cap_signaling_handle_configure_request(channel, command); 751 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP; 752 break; 753 default: 754 //@TODO: implement other signaling packets 755 break; 756 } 757 break; 758 759 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 760 switch (code) { 761 case CONFIGURE_RESPONSE: 762 channel->state = L2CAP_STATE_OPEN; 763 l2cap_emit_channel_opened(channel, 0); // success 764 l2cap_emit_credits(channel, 1); 765 break; 766 default: 767 //@TODO: implement other signaling packets 768 break; 769 } 770 break; 771 772 case L2CAP_STATE_WAIT_DISCONNECT: 773 switch (code) { 774 case DISCONNECTION_RESPONSE: 775 l2cap_finialize_channel_close(channel); 776 break; 777 default: 778 //@TODO: implement other signaling packets 779 break; 780 } 781 break; 782 783 case L2CAP_STATE_CLOSED: 784 // @TODO handle incoming requests 785 break; 786 787 case L2CAP_STATE_OPEN: 788 //@TODO: implement other signaling packets, e.g. re-configure 789 break; 790 default: 791 break; 792 } 793 // log_dbg("new state %u\n", channel->state); 794 } 795 796 797 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 798 799 // get code, signalind identifier and command len 800 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 801 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 802 803 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 804 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 805 return; 806 } 807 808 // general commands without an assigned channel 809 switch(code) { 810 811 case CONNECTION_REQUEST: { 812 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 813 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 814 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 815 return; 816 } 817 818 case ECHO_REQUEST: { 819 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 820 signaling_responses[signaling_responses_pending].handle = handle; 821 signaling_responses[signaling_responses_pending].code = code; 822 signaling_responses[signaling_responses_pending].sig_id = sig_id; 823 signaling_responses_pending++; 824 } 825 l2cap_run(); 826 return; 827 } 828 829 case INFORMATION_REQUEST: { 830 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 831 // we neither support connectionless L2CAP data nor support any flow control modes yet 832 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 833 signaling_responses[signaling_responses_pending].handle = handle; 834 signaling_responses[signaling_responses_pending].code = code; 835 signaling_responses[signaling_responses_pending].sig_id = sig_id; 836 signaling_responses[signaling_responses_pending].infoType = infoType; 837 signaling_responses_pending++; 838 } 839 l2cap_run(); 840 return; 841 } 842 843 default: 844 break; 845 } 846 847 848 // Get potential destination CID 849 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 850 851 // Find channel for this sig_id and connection handle 852 linked_item_t *it; 853 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 854 l2cap_channel_t * channel = (l2cap_channel_t *) it; 855 if (channel->handle == handle) { 856 if (code & 1) { 857 // match odd commands (responses) by previous signaling identifier 858 if (channel->local_sig_id == sig_id) { 859 l2cap_signaling_handler_channel(channel, command); 860 break; 861 } 862 } else { 863 // match even commands (requests) by local channel id 864 if (channel->local_cid == dest_cid) { 865 l2cap_signaling_handler_channel(channel, command); 866 break; 867 } 868 } 869 } 870 } 871 } 872 873 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 874 875 // Get Channel ID 876 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 877 878 // Signaling Packet? 879 if (channel_id == 1) { 880 881 // Get Connection 882 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 883 884 uint16_t command_offset = 8; 885 while (command_offset < size) { 886 887 // handle signaling commands 888 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 889 890 // increment command_offset 891 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 892 } 893 return; 894 } 895 896 // Find channel for this channel_id and connection handle 897 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 898 if (channel) { 899 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 900 } 901 } 902 903 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 904 switch (packet_type) { 905 case HCI_EVENT_PACKET: 906 l2cap_event_handler(packet, size); 907 break; 908 case HCI_ACL_DATA_PACKET: 909 l2cap_acl_handler(packet, size); 910 break; 911 default: 912 break; 913 } 914 } 915 916 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 917 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 918 channel->state = L2CAP_STATE_CLOSED; 919 l2cap_emit_channel_closed(channel); 920 // discard channel 921 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 922 free (channel); 923 } 924 925 l2cap_service_t * l2cap_get_service(uint16_t psm){ 926 linked_item_t *it; 927 928 // close open channels 929 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 930 l2cap_service_t * service = ((l2cap_service_t *) it); 931 if ( service->psm == psm){ 932 return service; 933 }; 934 } 935 return NULL; 936 } 937 938 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 939 // check for alread registered psm // TODO: emit error event 940 l2cap_service_t *service = l2cap_get_service(psm); 941 if (service) return; 942 943 // alloc structure // TODO: emit error event 944 service = malloc(sizeof(l2cap_service_t)); 945 if (!service) return; 946 947 // fill in 948 service->psm = psm; 949 service->mtu = mtu; 950 service->connection = connection; 951 service->packet_handler = packet_handler; 952 953 // add to services list 954 linked_list_add(&l2cap_services, (linked_item_t *) service); 955 } 956 957 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 958 l2cap_service_t *service = l2cap_get_service(psm); 959 if (!service) return; 960 linked_list_remove(&l2cap_services, (linked_item_t *) service); 961 free(service); 962 } 963 964 // 965 void l2cap_close_connection(void *connection){ 966 linked_item_t *it; 967 968 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 969 l2cap_channel_t * channel; 970 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 971 channel = (l2cap_channel_t *) it; 972 if (channel->connection == connection) { 973 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 974 } 975 } 976 977 // unregister services 978 it = (linked_item_t *) &l2cap_services; 979 while (it->next) { 980 l2cap_service_t * service = (l2cap_service_t *) it->next; 981 if (service->connection == connection){ 982 it->next = it->next->next; 983 free(service); 984 } else { 985 it = it->next; 986 } 987 } 988 989 // process 990 l2cap_run(); 991 } 992