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 // process outstanding signaling tasks 265 void l2cap_run(void){ 266 267 268 // 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 // open outgoing L2CAP channel 393 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler, 394 bd_addr_t address, uint16_t psm, uint16_t mtu){ 395 396 // alloc structure 397 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 398 // TODO: emit error event 399 if (!chan) return; 400 401 // limit local mtu to max acl packet length 402 if (mtu > hci_max_acl_data_packet_length()) { 403 mtu = hci_max_acl_data_packet_length(); 404 } 405 406 // fill in 407 BD_ADDR_COPY(chan->address, address); 408 chan->psm = psm; 409 chan->handle = 0; 410 chan->connection = connection; 411 chan->packet_handler = packet_handler; 412 chan->remote_mtu = L2CAP_MINIMAL_MTU; 413 chan->local_mtu = mtu; 414 chan->packets_granted = 0; 415 416 // set initial state 417 chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 418 chan->remote_sig_id = L2CAP_SIG_ID_INVALID; 419 chan->local_sig_id = L2CAP_SIG_ID_INVALID; 420 421 // add to connections list 422 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 423 424 l2cap_run(); 425 } 426 427 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){ 428 // find channel for local_cid 429 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 430 if (channel) { 431 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 432 } 433 // process 434 l2cap_run(); 435 } 436 437 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 438 linked_item_t *it = (linked_item_t *) &l2cap_channels; 439 while (it->next){ 440 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 441 if ( ! BD_ADDR_CMP( channel->address, address) ){ 442 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 443 // failure, forward error code 444 l2cap_emit_channel_opened(channel, status); 445 // discard channel 446 it->next = it->next->next; 447 free (channel); 448 } 449 } else { 450 it = it->next; 451 } 452 } 453 } 454 455 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 456 linked_item_t *it; 457 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 458 l2cap_channel_t * channel = (l2cap_channel_t *) it; 459 if ( ! BD_ADDR_CMP( channel->address, address) ){ 460 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 461 // success, start l2cap handshake 462 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 463 channel->handle = handle; 464 channel->local_cid = l2cap_next_local_cid(); 465 } 466 } 467 } 468 // process 469 l2cap_run(); 470 } 471 472 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 473 474 bd_addr_t address; 475 hci_con_handle_t handle; 476 linked_item_t *it; 477 478 switch(packet[0]){ 479 480 // handle connection complete events 481 case HCI_EVENT_CONNECTION_COMPLETE: 482 bt_flip_addr(address, &packet[5]); 483 if (packet[2] == 0){ 484 handle = READ_BT_16(packet, 3); 485 l2cap_handle_connection_success_for_addr(address, handle); 486 } else { 487 l2cap_handle_connection_failed_for_addr(address, packet[2]); 488 } 489 break; 490 491 // handle successful create connection cancel command 492 case HCI_EVENT_COMMAND_COMPLETE: 493 if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) { 494 if (packet[5] == 0){ 495 bt_flip_addr(address, &packet[6]); 496 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 497 l2cap_handle_connection_failed_for_addr(address, 0x16); 498 } 499 } 500 l2cap_run(); // try sending signaling packets first 501 break; 502 503 case HCI_EVENT_COMMAND_STATUS: 504 l2cap_run(); // try sending signaling packets first 505 break; 506 507 // handle disconnection complete events 508 case HCI_EVENT_DISCONNECTION_COMPLETE: 509 // send l2cap disconnect events for all channels on this handle 510 handle = READ_BT_16(packet, 3); 511 it = (linked_item_t *) &l2cap_channels; 512 while (it->next){ 513 l2cap_channel_t * channel = (l2cap_channel_t *) it->next; 514 if ( channel->handle == handle ){ 515 // update prev item before free'ing next element - don't call l2cap_finalize_channel_close 516 it->next = it->next->next; 517 l2cap_emit_channel_closed(channel); 518 free (channel); 519 } else { 520 it = it->next; 521 } 522 } 523 break; 524 525 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 526 l2cap_run(); // try sending signaling packets first 527 l2cap_hand_out_credits(); 528 break; 529 530 // HCI Connection Timeouts 531 case L2CAP_EVENT_TIMEOUT_CHECK: 532 handle = READ_BT_16(packet, 2); 533 if (hci_authentication_active_for_handle(handle)) break; 534 l2cap_channel_t * channel; 535 int used = 0; 536 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 537 channel = (l2cap_channel_t *) it; 538 if (channel->handle == handle) { 539 used = 1; 540 } 541 } 542 if (used) break; 543 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) break; 544 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 545 break; 546 547 default: 548 break; 549 } 550 551 // pass on 552 (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size); 553 } 554 555 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 556 channel->remote_sig_id = identifier; 557 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 558 l2cap_run(); 559 } 560 561 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 562 563 // log_dbg("l2cap_handle_connection_request for handle %u, psm %u cid %u\n", handle, psm, source_cid); 564 l2cap_service_t *service = l2cap_get_service(psm); 565 if (!service) { 566 // 0x0002 PSM not supported 567 // log_dbg("l2cap_handle_connection_request no PSM for psm %u/n", psm); 568 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, 0x0002, 0); 569 return; 570 } 571 572 hci_connection_t * hci_connection = connection_for_handle( handle ); 573 if (!hci_connection) { 574 log_err("no hci_connection for handle %u\n", handle); 575 // TODO: emit error 576 return; 577 } 578 // alloc structure 579 // log_dbg("l2cap_handle_connection_request register channel\n"); 580 l2cap_channel_t * channel = malloc(sizeof(l2cap_channel_t)); 581 // TODO: emit error event 582 if (!channel) return; 583 584 // fill in 585 BD_ADDR_COPY(channel->address, hci_connection->address); 586 channel->psm = psm; 587 channel->handle = handle; 588 channel->connection = service->connection; 589 channel->packet_handler = service->packet_handler; 590 channel->local_cid = l2cap_next_local_cid(); 591 channel->remote_cid = source_cid; 592 channel->local_mtu = service->mtu; 593 channel->remote_mtu = L2CAP_DEFAULT_MTU; 594 channel->packets_granted = 0; 595 channel->remote_sig_id = sig_id; 596 597 // limit local mtu to max acl packet length 598 if (channel->local_mtu > hci_max_acl_data_packet_length()) { 599 channel->local_mtu = hci_max_acl_data_packet_length(); 600 } 601 602 // set initial state 603 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 604 605 // add to connections list 606 linked_list_add(&l2cap_channels, (linked_item_t *) channel); 607 608 // emit incoming connection request 609 l2cap_emit_connection_request(channel); 610 } 611 612 void l2cap_accept_connection_internal(uint16_t local_cid){ 613 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 614 if (!channel) { 615 log_err("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid); 616 return; 617 } 618 619 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 620 621 // process 622 l2cap_run(); 623 } 624 625 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){ 626 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 627 if (!channel) { 628 log_err( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid); 629 return; 630 } 631 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 632 channel->reason = reason; 633 l2cap_run(); 634 } 635 636 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 637 638 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 639 640 // accept the other's configuration options 641 uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 642 uint16_t pos = 8; 643 while (pos < end_pos){ 644 uint8_t type = command[pos++]; 645 uint8_t length = command[pos++]; 646 // MTU { type(8): 1, len(8):2, MTU(16) } 647 if ((type & 0x7f) == 1 && length == 2){ 648 channel->remote_mtu = READ_BT_16(command, pos); 649 // log_dbg("l2cap cid %u, remote mtu %u\n", channel->local_cid, channel->remote_mtu); 650 } 651 pos += length; 652 } 653 } 654 655 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 656 657 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 658 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 659 uint16_t result = 0; 660 661 log_dbg("signaling handler code %u, state %u\n", code, channel->state); 662 663 // handle DISCONNECT REQUESTS seperately 664 if (code == DISCONNECTION_REQUEST){ 665 switch (channel->state){ 666 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 667 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_WILL_SEND_CONFIG_REQ_RSP: 668 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 669 case L2CAP_STATE_WAIT_CONFIG_REQ: 670 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 671 case L2CAP_STATE_WILL_SEND_CONFIG_REQ: 672 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP: 673 case L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP: 674 case L2CAP_STATE_OPEN: 675 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 676 case L2CAP_STATE_WAIT_DISCONNECT: 677 l2cap_handle_disconnect_request(channel, identifier); 678 break; 679 680 default: 681 // ignore in other states 682 break; 683 } 684 return; 685 } 686 687 switch (channel->state) { 688 689 case L2CAP_STATE_WAIT_CONNECT_RSP: 690 switch (code){ 691 case CONNECTION_RESPONSE: 692 result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 693 switch (result) { 694 case 0: 695 // successful connection 696 channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 697 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ; 698 #if 0 699 channel->state = L2CAP_STATE_OPEN; 700 l2cap_emit_channel_opened(channel, 0); // success 701 l2cap_emit_credits(channel, 1); 702 #endif 703 break; 704 case 1: 705 // connection pending. get some coffee 706 break; 707 default: 708 // channel closed 709 channel->state = L2CAP_STATE_CLOSED; 710 711 // map l2cap connection response result to BTstack status enumeration 712 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 713 714 // drop link key if security block 715 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 716 hci_drop_link_key_for_bd_addr(&channel->address); 717 } 718 719 // discard channel 720 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 721 free (channel); 722 break; 723 } 724 break; 725 726 default: 727 //@TODO: implement other signaling packets 728 break; 729 } 730 break; 731 732 case L2CAP_STATE_WAIT_CONFIG_REQ_OR_SEND_CONFIG_REQ: 733 switch (code) { 734 case CONFIGURE_REQUEST: 735 l2cap_signaling_handle_configure_request(channel, command); 736 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_AND_CONFIG_REQ_RSP; 737 break; 738 default: 739 //@TODO: implement other signaling packets 740 break; 741 } 742 break; 743 744 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_CONFIG_REQ: 745 switch (code) { 746 case CONFIGURE_RESPONSE: 747 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 748 break; 749 case CONFIGURE_REQUEST: 750 l2cap_signaling_handle_configure_request(channel, command); 751 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP_OR_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: 760 switch (code) { 761 case CONFIGURE_REQUEST: 762 l2cap_signaling_handle_configure_request(channel, command); 763 channel->state = L2CAP_STATE_WILL_SEND_CONFIG_REQ_RSP; 764 break; 765 default: 766 //@TODO: implement other signaling packets 767 break; 768 } 769 break; 770 771 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 772 switch (code) { 773 case CONFIGURE_RESPONSE: 774 channel->state = L2CAP_STATE_OPEN; 775 l2cap_emit_channel_opened(channel, 0); // success 776 l2cap_emit_credits(channel, 1); 777 break; 778 default: 779 //@TODO: implement other signaling packets 780 break; 781 } 782 break; 783 784 case L2CAP_STATE_WAIT_DISCONNECT: 785 switch (code) { 786 case DISCONNECTION_RESPONSE: 787 l2cap_finialize_channel_close(channel); 788 break; 789 default: 790 //@TODO: implement other signaling packets 791 break; 792 } 793 break; 794 795 case L2CAP_STATE_CLOSED: 796 // @TODO handle incoming requests 797 break; 798 799 case L2CAP_STATE_OPEN: 800 //@TODO: implement other signaling packets, e.g. re-configure 801 break; 802 default: 803 break; 804 } 805 // log_dbg("new state %u\n", channel->state); 806 } 807 808 809 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){ 810 811 // get code, signalind identifier and command len 812 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 813 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 814 815 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST 816 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){ 817 return; 818 } 819 820 // general commands without an assigned channel 821 switch(code) { 822 823 case CONNECTION_REQUEST: { 824 uint16_t psm = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 825 uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 826 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 827 return; 828 } 829 830 case ECHO_REQUEST: { 831 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 832 signaling_responses[signaling_responses_pending].handle = handle; 833 signaling_responses[signaling_responses_pending].code = code; 834 signaling_responses[signaling_responses_pending].sig_id = sig_id; 835 signaling_responses_pending++; 836 } 837 l2cap_run(); 838 return; 839 } 840 841 case INFORMATION_REQUEST: { 842 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 843 // we neither support connectionless L2CAP data nor support any flow control modes yet 844 uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 845 signaling_responses[signaling_responses_pending].handle = handle; 846 signaling_responses[signaling_responses_pending].code = code; 847 signaling_responses[signaling_responses_pending].sig_id = sig_id; 848 signaling_responses[signaling_responses_pending].infoType = infoType; 849 signaling_responses_pending++; 850 } 851 l2cap_run(); 852 return; 853 } 854 855 default: 856 break; 857 } 858 859 860 // Get potential destination CID 861 uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 862 863 // Find channel for this sig_id and connection handle 864 linked_item_t *it; 865 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 866 l2cap_channel_t * channel = (l2cap_channel_t *) it; 867 if (channel->handle == handle) { 868 if (code & 1) { 869 // match odd commands (responses) by previous signaling identifier 870 if (channel->local_sig_id == sig_id) { 871 l2cap_signaling_handler_channel(channel, command); 872 break; 873 } 874 } else { 875 // match even commands (requests) by local channel id 876 if (channel->local_cid == dest_cid) { 877 l2cap_signaling_handler_channel(channel, command); 878 break; 879 } 880 } 881 } 882 } 883 } 884 885 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 886 887 // Get Channel ID 888 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 889 890 // Signaling Packet? 891 if (channel_id == 1) { 892 893 // Get Connection 894 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 895 896 uint16_t command_offset = 8; 897 while (command_offset < size) { 898 899 // handle signaling commands 900 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 901 902 // increment command_offset 903 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 904 } 905 906 l2cap_run(); 907 908 return; 909 } 910 911 // Find channel for this channel_id and connection handle 912 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id); 913 if (channel) { 914 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 915 } 916 } 917 918 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){ 919 switch (packet_type) { 920 case HCI_EVENT_PACKET: 921 l2cap_event_handler(packet, size); 922 break; 923 case HCI_ACL_DATA_PACKET: 924 l2cap_acl_handler(packet, size); 925 break; 926 default: 927 break; 928 } 929 } 930 931 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 932 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 933 channel->state = L2CAP_STATE_CLOSED; 934 l2cap_emit_channel_closed(channel); 935 // discard channel 936 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 937 free (channel); 938 } 939 940 l2cap_service_t * l2cap_get_service(uint16_t psm){ 941 linked_item_t *it; 942 943 // close open channels 944 for (it = (linked_item_t *) l2cap_services; it ; it = it->next){ 945 l2cap_service_t * service = ((l2cap_service_t *) it); 946 if ( service->psm == psm){ 947 return service; 948 }; 949 } 950 return NULL; 951 } 952 953 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu){ 954 // check for alread registered psm // TODO: emit error event 955 l2cap_service_t *service = l2cap_get_service(psm); 956 if (service) return; 957 958 // alloc structure // TODO: emit error event 959 service = malloc(sizeof(l2cap_service_t)); 960 if (!service) return; 961 962 // fill in 963 service->psm = psm; 964 service->mtu = mtu; 965 service->connection = connection; 966 service->packet_handler = packet_handler; 967 968 // add to services list 969 linked_list_add(&l2cap_services, (linked_item_t *) service); 970 } 971 972 void l2cap_unregister_service_internal(void *connection, uint16_t psm){ 973 l2cap_service_t *service = l2cap_get_service(psm); 974 if (!service) return; 975 linked_list_remove(&l2cap_services, (linked_item_t *) service); 976 free(service); 977 } 978 979 // 980 void l2cap_close_connection(void *connection){ 981 linked_item_t *it; 982 983 // close open channels - note to myself: no channel is freed, so no new for fancy iterator tricks 984 l2cap_channel_t * channel; 985 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 986 channel = (l2cap_channel_t *) it; 987 if (channel->connection == connection) { 988 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 989 } 990 } 991 992 // unregister services 993 it = (linked_item_t *) &l2cap_services; 994 while (it->next) { 995 l2cap_service_t * service = (l2cap_service_t *) it->next; 996 if (service->connection == connection){ 997 it->next = it->next->next; 998 free(service); 999 } else { 1000 it = it->next; 1001 } 1002 } 1003 1004 // process 1005 l2cap_run(); 1006 } 1007