1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 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 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "l2cap.c" 39 40 /* 41 * l2cap.c 42 * 43 * Logical Link Control and Adaption Protocl (L2CAP) 44 * 45 * Created by Matthias Ringwald on 5/16/09. 46 */ 47 48 #include "l2cap.h" 49 #include "hci.h" 50 #include "hci_dump.h" 51 #include "bluetooth_sdp.h" 52 #include "btstack_debug.h" 53 #include "btstack_event.h" 54 #include "btstack_memory.h" 55 56 #include <stdarg.h> 57 #include <string.h> 58 59 #include <stdio.h> 60 61 // nr of buffered acl packets in outgoing queue to get max performance 62 #define NR_BUFFERED_ACL_PACKETS 3 63 64 // used to cache l2cap rejects, echo, and informational requests 65 #define NR_PENDING_SIGNALING_RESPONSES 3 66 67 // nr of credits provided to remote if credits fall below watermark 68 #define L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_WATERMARK 5 69 #define L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_INCREMENT 5 70 71 // offsets for L2CAP SIGNALING COMMANDS 72 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 73 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 74 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 75 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 76 77 #if defined(ENABLE_LE_DATA_CHANNELS) || defined(ENABLE_CLASSIC) 78 #define L2CAP_USES_CHANNELS 79 #endif 80 81 // prototypes 82 static void l2cap_run(void); 83 static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 84 static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size ); 85 static void l2cap_notify_channel_can_send(void); 86 static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel); 87 static l2cap_fixed_channel_t * l2cap_fixed_channel_for_channel_id(uint16_t local_cid); 88 #ifdef ENABLE_CLASSIC 89 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel); 90 static void l2cap_handle_connection_complete(hci_con_handle_t con_handle, l2cap_channel_t * channel); 91 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 92 static inline l2cap_service_t * l2cap_get_service(uint16_t psm); 93 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 94 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 95 static void l2cap_emit_incoming_connection(l2cap_channel_t *channel); 96 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 97 #endif 98 #ifdef ENABLE_LE_DATA_CHANNELS 99 static void l2cap_emit_le_channel_opened(l2cap_channel_t *channel, uint8_t status); 100 static void l2cap_emit_le_channel_closed(l2cap_channel_t * channel); 101 static void l2cap_emit_le_incoming_connection(l2cap_channel_t *channel); 102 static void l2cap_le_notify_channel_can_send(l2cap_channel_t *channel); 103 static void l2cap_le_finialize_channel_close(l2cap_channel_t *channel); 104 static inline l2cap_service_t * l2cap_le_get_service(uint16_t psm); 105 #endif 106 #ifdef L2CAP_USES_CHANNELS 107 static void l2cap_dispatch_to_channel(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size); 108 static l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid); 109 static l2cap_channel_t * l2cap_create_channel_entry(btstack_packet_handler_t packet_handler, l2cap_channel_type_t channel_type, bd_addr_t address, bd_addr_type_t address_type, 110 uint16_t psm, uint16_t local_mtu, gap_security_level_t security_level); 111 #endif 112 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 113 static void l2cap_ertm_notify_channel_can_send(l2cap_channel_t * channel); 114 static void l2cap_ertm_monitor_timeout_callback(btstack_timer_source_t * ts); 115 static void l2cap_ertm_retransmission_timeout_callback(btstack_timer_source_t * ts); 116 #endif 117 118 // l2cap_fixed_channel_t entries 119 #ifdef ENABLE_BLE 120 static l2cap_fixed_channel_t l2cap_fixed_channel_att; 121 static l2cap_fixed_channel_t l2cap_fixed_channel_sm; 122 #endif 123 #ifdef ENABLE_CLASSIC 124 static l2cap_fixed_channel_t l2cap_fixed_channel_connectionless; 125 #endif 126 127 #ifdef ENABLE_CLASSIC 128 static btstack_linked_list_t l2cap_services; 129 static uint8_t require_security_level2_for_outgoing_sdp; 130 #endif 131 132 #ifdef ENABLE_LE_DATA_CHANNELS 133 static btstack_linked_list_t l2cap_le_services; 134 #endif 135 136 // single list of channels for Classic Channels, LE Data Channels, Classic Connectionless, ATT, and SM 137 static btstack_linked_list_t l2cap_channels; 138 139 // used to cache l2cap rejects, echo, and informational requests 140 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 141 static int signaling_responses_pending; 142 static btstack_packet_callback_registration_t hci_event_callback_registration; 143 144 #ifdef ENABLE_BLE 145 // only used for connection parameter update events 146 static btstack_packet_handler_t l2cap_event_packet_handler; 147 static uint16_t l2cap_le_custom_max_mtu; 148 #endif 149 150 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 151 152 /* 153 * CRC lookup table for generator polynom D^16 + D^15 + D^2 + 1 154 */ 155 static const uint16_t crc16_table[256] = { 156 0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241, 0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440, 157 0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40, 0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841, 158 0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40, 0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41, 159 0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641, 0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040, 160 0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240, 0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441, 161 0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41, 0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840, 162 0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41, 0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40, 163 0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640, 0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041, 164 0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240, 0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441, 165 0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41, 0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840, 166 0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41, 0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40, 167 0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640, 0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041, 168 0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241, 0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440, 169 0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40, 0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841, 170 0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40, 0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41, 171 0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641, 0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040, 172 }; 173 174 static uint16_t crc16_calc(uint8_t * data, uint16_t len){ 175 uint16_t crc = 0; // initial value = 0 176 while (len--){ 177 crc = (crc >> 8) ^ crc16_table[ (crc ^ ((uint16_t) *data++)) & 0x00FF ]; 178 } 179 return crc; 180 } 181 182 static inline uint16_t l2cap_encanced_control_field_for_information_frame(uint8_t tx_seq, int final, uint8_t req_seq, l2cap_segmentation_and_reassembly_t sar){ 183 return (((uint16_t) sar) << 14) | (req_seq << 8) | (final << 7) | (tx_seq << 1) | 0; 184 } 185 186 static inline uint16_t l2cap_encanced_control_field_for_supevisor_frame(l2cap_supervisory_function_t supervisory_function, int poll, int final, uint8_t req_seq){ 187 return (req_seq << 8) | (final << 7) | (poll << 4) | (((int) supervisory_function) << 2) | 1; 188 } 189 190 static int l2cap_next_ertm_seq_nr(int seq_nr){ 191 return (seq_nr + 1) & 0x3f; 192 } 193 194 static int l2cap_ertm_can_store_packet_now(l2cap_channel_t * channel){ 195 // get num free tx buffers 196 int num_tx_buffers_used = channel->tx_write_index - channel->tx_read_index; 197 if (num_tx_buffers_used < 0){ 198 num_tx_buffers_used += channel->num_tx_buffers; 199 } 200 int num_free_tx_buffers = channel->num_tx_buffers - num_tx_buffers_used; 201 // calculate num tx buffers for remote MTU 202 int num_tx_buffers_for_max_remote_mtu; 203 if (channel->remote_mtu <= channel->remote_mps){ 204 // MTU fits into single packet 205 num_tx_buffers_for_max_remote_mtu = 1; 206 } else { 207 // include SDU Length 208 num_tx_buffers_for_max_remote_mtu = (channel->remote_mtu + 2 + (channel->remote_mps - 1)) / channel->remote_mps; 209 } 210 return num_tx_buffers_for_max_remote_mtu <= num_free_tx_buffers; 211 } 212 213 static void l2cap_ertm_next_tx_write_index(l2cap_channel_t * channel){ 214 channel->tx_write_index++; 215 if (channel->tx_write_index < channel->num_tx_buffers) return; 216 channel->tx_write_index = 0; 217 } 218 219 static void l2cap_ertm_start_monitor_timer(l2cap_channel_t * channel){ 220 log_info("Start Monitor timer"); 221 btstack_run_loop_remove_timer(&channel->monitor_timer); 222 btstack_run_loop_set_timer_handler(&channel->monitor_timer, &l2cap_ertm_monitor_timeout_callback); 223 btstack_run_loop_set_timer_context(&channel->monitor_timer, channel); 224 btstack_run_loop_set_timer(&channel->monitor_timer, channel->local_monitor_timeout_ms); 225 btstack_run_loop_add_timer(&channel->monitor_timer); 226 } 227 228 static void l2cap_ertm_stop_monitor_timer(l2cap_channel_t * channel){ 229 log_info("Stop Monitor timer"); 230 btstack_run_loop_remove_timer(&channel->monitor_timer); 231 } 232 233 static void l2cap_ertm_start_retransmission_timer(l2cap_channel_t * channel){ 234 log_info("Start Retransmission timer"); 235 btstack_run_loop_remove_timer(&channel->retransmission_timer); 236 btstack_run_loop_set_timer_handler(&channel->retransmission_timer, &l2cap_ertm_retransmission_timeout_callback); 237 btstack_run_loop_set_timer_context(&channel->retransmission_timer, channel); 238 btstack_run_loop_set_timer(&channel->retransmission_timer, channel->local_retransmission_timeout_ms); 239 btstack_run_loop_add_timer(&channel->retransmission_timer); 240 } 241 242 static void l2cap_ertm_stop_retransmission_timer(l2cap_channel_t * l2cap_channel){ 243 log_info("Stop Retransmission timer"); 244 btstack_run_loop_remove_timer(&l2cap_channel->retransmission_timer); 245 } 246 247 static void l2cap_ertm_monitor_timeout_callback(btstack_timer_source_t * ts){ 248 log_info("Monitor timeout"); 249 l2cap_channel_t * l2cap_channel = (l2cap_channel_t *) btstack_run_loop_get_timer_context(ts); 250 251 // TODO: we assume that it's the oldest packet 252 l2cap_ertm_tx_packet_state_t * tx_state; 253 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 254 255 // check retry count 256 if (tx_state->retry_count < l2cap_channel->remote_max_transmit){ 257 // increment retry count 258 tx_state->retry_count++; 259 260 l2cap_ertm_start_monitor_timer(l2cap_channel); 261 262 // send RR/P=1 263 l2cap_channel->send_supervisor_frame_receiver_ready_poll = 1; 264 } else { 265 log_info("Monitor timer expired & retry count >= max transmit -> disconnect"); 266 l2cap_channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 267 } 268 l2cap_run(); 269 } 270 271 static void l2cap_ertm_retransmission_timeout_callback(btstack_timer_source_t * ts){ 272 log_info("Retransmission timeout"); 273 l2cap_channel_t * l2cap_channel = (l2cap_channel_t *) btstack_run_loop_get_timer_context(ts); 274 275 // TODO: we assume that it's the oldest packet 276 l2cap_ertm_tx_packet_state_t * tx_state; 277 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 278 279 // set retry count = 1 280 tx_state->retry_count = 1; 281 282 // start monitor timer 283 l2cap_ertm_start_monitor_timer(l2cap_channel); 284 285 // send RR/P=1 286 l2cap_channel->send_supervisor_frame_receiver_ready_poll = 1; 287 l2cap_run(); 288 } 289 290 static int l2cap_ertm_send_information_frame(l2cap_channel_t * channel, int index, int final){ 291 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[index]; 292 hci_reserve_packet_buffer(); 293 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 294 uint16_t control = l2cap_encanced_control_field_for_information_frame(tx_state->tx_seq, final, channel->req_seq, tx_state->sar); 295 log_info("I-Frame: control 0x%04x", control); 296 little_endian_store_16(acl_buffer, 8, control); 297 memcpy(&acl_buffer[8+2], &channel->tx_packets_data[index * channel->local_mtu], tx_state->len); 298 // (re-)start retransmission timer on 299 l2cap_ertm_start_retransmission_timer(channel); 300 // send 301 return l2cap_send_prepared(channel->local_cid, 2 + tx_state->len); 302 } 303 304 static void l2cap_ertm_store_fragment(l2cap_channel_t * channel, l2cap_segmentation_and_reassembly_t sar, uint16_t sdu_length, uint8_t * data, uint16_t len){ 305 // get next index for storing packets 306 int index = channel->tx_write_index; 307 308 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[index]; 309 tx_state->tx_seq = channel->next_tx_seq; 310 tx_state->len = len; 311 tx_state->sar = sar; 312 tx_state->retry_count = 0; 313 314 uint8_t * tx_packet = &channel->tx_packets_data[index * channel->local_mtu]; 315 int pos = 0; 316 if (sar == L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU){ 317 little_endian_store_16(tx_packet, 0, sdu_length); 318 pos += 2; 319 } 320 memcpy(&tx_packet[pos], data, len); 321 322 // update 323 channel->next_tx_seq = l2cap_next_ertm_seq_nr(channel->next_tx_seq); 324 l2cap_ertm_next_tx_write_index(channel); 325 326 log_info("l2cap_ertm_store_fragment: after store, tx_read_index %u, tx_write_index %u", channel->tx_read_index, channel->tx_write_index); 327 328 } 329 330 static int l2cap_ertm_send(l2cap_channel_t * channel, uint8_t * data, uint16_t len){ 331 if (len > channel->remote_mtu){ 332 log_error("l2cap_send cid 0x%02x, data length exceeds remote MTU.", channel->local_cid); 333 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 334 } 335 336 // check if it needs to get fragmented 337 if (len > channel->remote_mps){ 338 // fragmentation needed. 339 l2cap_segmentation_and_reassembly_t sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU; 340 int chunk_len; 341 while (len){ 342 switch (sar){ 343 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 344 chunk_len = channel->remote_mps - 2; // sdu_length 345 l2cap_ertm_store_fragment(channel, sar, len, data, chunk_len); 346 len -= chunk_len; 347 sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU; 348 break; 349 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 350 chunk_len = channel->remote_mps; 351 if (chunk_len >= len){ 352 sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU; 353 chunk_len = len; 354 } 355 l2cap_ertm_store_fragment(channel, sar, len, data, chunk_len); 356 len -= chunk_len; 357 break; 358 default: 359 break; 360 } 361 } 362 363 } else { 364 l2cap_ertm_store_fragment(channel, L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU, 0, data, len); 365 } 366 367 // try to send 368 l2cap_run(); 369 return 0; 370 } 371 372 static uint16_t l2cap_setup_options_ertm_request(l2cap_channel_t * channel, uint8_t * config_options){ 373 int pos = 0; 374 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL; 375 config_options[pos++] = 9; // length 376 config_options[pos++] = (uint8_t) channel->mode; 377 config_options[pos++] = channel->num_rx_buffers; // == TxWindows size 378 config_options[pos++] = channel->local_max_transmit; 379 little_endian_store_16( config_options, pos, channel->local_retransmission_timeout_ms); 380 pos += 2; 381 little_endian_store_16( config_options, pos, channel->local_monitor_timeout_ms); 382 pos += 2; 383 little_endian_store_16( config_options, pos, channel->local_mps); 384 pos += 2; 385 // 386 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; 387 config_options[pos++] = 2; // length 388 little_endian_store_16(config_options, pos, channel->local_mtu); 389 pos += 2; 390 // 391 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE; 392 config_options[pos++] = 1; // length 393 config_options[pos++] = channel->fcs_option; 394 return pos; // 11+4+3=18 395 } 396 397 static uint16_t l2cap_setup_options_ertm_response(l2cap_channel_t * channel, uint8_t * config_options){ 398 int pos = 0; 399 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL; 400 config_options[pos++] = 9; // length 401 config_options[pos++] = (uint8_t) channel->mode; 402 // less or equal to remote tx window size 403 config_options[pos++] = btstack_min(channel->num_tx_buffers, channel->remote_tx_window_size); 404 // max transmit in response shall be ignored -> use sender values 405 config_options[pos++] = channel->remote_max_transmit; 406 // A value for the Retransmission time-out shall be sent in a positive Configuration Response 407 // and indicates the value that will be used by the sender of the Configuration Response -> use our value 408 little_endian_store_16( config_options, pos, channel->local_retransmission_timeout_ms); 409 pos += 2; 410 // A value for the Monitor time-out shall be sent in a positive Configuration Response 411 // and indicates the value that will be used by the sender of the Configuration Response -> use our value 412 little_endian_store_16( config_options, pos, channel->local_monitor_timeout_ms); 413 pos += 2; 414 // less or equal to remote mps 415 little_endian_store_16( config_options, pos, btstack_min(channel->local_mps, channel->remote_mps)); 416 pos += 2; 417 // 418 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; // MTU 419 config_options[pos++] = 2; // length 420 little_endian_store_16(config_options, pos, channel->remote_mtu); 421 pos += 2; 422 #if 0 423 // 424 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE; 425 config_options[pos++] = 1; // length 426 config_options[pos++] = channel->fcs_option; 427 #endif 428 return pos; // 11+4=15 429 } 430 431 static int l2cap_ertm_send_supervisor_frame(l2cap_channel_t * channel, uint16_t control){ 432 hci_reserve_packet_buffer(); 433 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 434 log_info("S-Frame: control 0x%04x", control); 435 little_endian_store_16(acl_buffer, 8, control); 436 return l2cap_send_prepared(channel->local_cid, 2); 437 } 438 439 static uint8_t l2cap_ertm_validate_local_config(l2cap_ertm_config_t * ertm_config){ 440 441 uint8_t result = ERROR_CODE_SUCCESS; 442 if (ertm_config->max_transmit < 1){ 443 log_error("max_transmit must be >= 1"); 444 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 445 } 446 if (ertm_config->retransmission_timeout_ms < 2000){ 447 log_error("retransmission_timeout_ms must be >= 2000 ms"); 448 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 449 } 450 if (ertm_config->monitor_timeout_ms < 12000){ 451 log_error("monitor_timeout_ms must be >= 12000 ms"); 452 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 453 } 454 if (ertm_config->local_mtu < 48){ 455 log_error("local_mtu must be >= 48"); 456 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 457 } 458 if (ertm_config->num_rx_buffers < 1){ 459 log_error("num_rx_buffers must be >= 1"); 460 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 461 } 462 if (ertm_config->num_tx_buffers < 1){ 463 log_error("num_rx_buffers must be >= 1"); 464 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 465 } 466 return result; 467 } 468 469 static void l2cap_ertm_configure_channel(l2cap_channel_t * channel, l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size){ 470 471 channel->mode = L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION; 472 channel->ertm_mandatory = ertm_config->ertm_mandatory; 473 channel->local_max_transmit = ertm_config->max_transmit; 474 channel->local_retransmission_timeout_ms = ertm_config->retransmission_timeout_ms; 475 channel->local_monitor_timeout_ms = ertm_config->monitor_timeout_ms; 476 channel->local_mtu = ertm_config->local_mtu; 477 channel->num_rx_buffers = ertm_config->num_rx_buffers; 478 channel->num_tx_buffers = ertm_config->num_tx_buffers; 479 480 // align buffer to 16-byte boundary, just in case 481 int bytes_till_alignment = 16 - (((uintptr_t) buffer) & 0x0f); 482 buffer += bytes_till_alignment; 483 size -= bytes_till_alignment; 484 485 // setup state buffers 486 uint32_t pos = 0; 487 channel->rx_packets_state = (l2cap_ertm_rx_packet_state_t *) &buffer[pos]; 488 pos += ertm_config->num_rx_buffers * sizeof(l2cap_ertm_rx_packet_state_t); 489 channel->tx_packets_state = (l2cap_ertm_tx_packet_state_t *) &buffer[pos]; 490 pos += ertm_config->num_tx_buffers * sizeof(l2cap_ertm_tx_packet_state_t); 491 492 // setup reassembly buffer 493 channel->reassembly_buffer = &buffer[pos]; 494 pos += ertm_config->local_mtu; 495 496 // divide rest of data equally 497 channel->local_mps = (size - pos) / (ertm_config->num_rx_buffers + ertm_config->num_tx_buffers); 498 log_info("Local MPS: %u", channel->local_mps); 499 channel->rx_packets_data = &buffer[pos]; 500 pos += ertm_config->num_rx_buffers * channel->local_mps; 501 channel->tx_packets_data = &buffer[pos]; 502 503 // Issue: iOS (e.g. 10.2) uses "No FCS" as default while Core 5.0 specifies "FCS" as default 504 // Workaround: try to actively negotiate "No FCS" and fall back to "FCS" if "No FCS" is rejected 505 // This works as iOS accepts the "No FCS" request, hence the default value is only used on non-iOS devices 506 channel->fcs_option = 0; 507 } 508 509 uint8_t l2cap_create_ertm_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm, 510 l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size, uint16_t * out_local_cid){ 511 512 log_info("L2CAP_CREATE_ERTM_CHANNEL addr %s, psm 0x%x, local mtu %u", bd_addr_to_str(address), psm, ertm_config->local_mtu); 513 514 // validate local config 515 uint8_t result = l2cap_ertm_validate_local_config(ertm_config); 516 if (result) return result; 517 518 l2cap_channel_t * channel = l2cap_create_channel_entry(packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, address, BD_ADDR_TYPE_CLASSIC, psm, ertm_config->local_mtu, LEVEL_0); 519 if (!channel) { 520 return BTSTACK_MEMORY_ALLOC_FAILED; 521 } 522 523 // configure ERTM 524 l2cap_ertm_configure_channel(channel, ertm_config, buffer, size); 525 526 // add to connections list 527 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel); 528 529 // store local_cid 530 if (out_local_cid){ 531 *out_local_cid = channel->local_cid; 532 } 533 534 // check if hci connection is already usable 535 hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_CLASSIC); 536 if (conn){ 537 log_info("l2cap_create_channel, hci connection already exists"); 538 l2cap_handle_connection_complete(conn->con_handle, channel); 539 // check if remote supported fearures are already received 540 if (conn->bonding_flags & BONDING_RECEIVED_REMOTE_FEATURES) { 541 l2cap_handle_remote_supported_features_received(channel); 542 } 543 } 544 545 l2cap_run(); 546 547 return 0; 548 } 549 550 static void l2cap_ertm_notify_channel_can_send(l2cap_channel_t * channel){ 551 if (l2cap_ertm_can_store_packet_now(channel)){ 552 channel->waiting_for_can_send_now = 0; 553 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 554 } 555 } 556 557 uint8_t l2cap_accept_ertm_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size){ 558 559 log_info("L2CAP_ACCEPT_ERTM_CONNECTION local_cid 0x%x", local_cid); 560 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 561 if (!channel) { 562 log_error("l2cap_accept_connection called but local_cid 0x%x not found", local_cid); 563 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 564 } 565 566 // validate local config 567 uint8_t result = l2cap_ertm_validate_local_config(ertm_config); 568 if (result) return result; 569 570 // configure L2CAP ERTM 571 l2cap_ertm_configure_channel(channel, ertm_config, buffer, size); 572 573 // continue 574 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 575 576 // process 577 l2cap_run(); 578 579 return ERROR_CODE_SUCCESS; 580 } 581 582 uint8_t l2cap_ertm_set_busy(uint16_t local_cid){ 583 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 584 if (!channel) { 585 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 586 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 587 } 588 if (!channel->local_busy){ 589 channel->local_busy = 1; 590 channel->send_supervisor_frame_receiver_not_ready = 1; 591 l2cap_run(); 592 } 593 return ERROR_CODE_SUCCESS; 594 } 595 596 uint8_t l2cap_ertm_set_ready(uint16_t local_cid){ 597 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 598 if (!channel) { 599 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 600 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 601 } 602 if (channel->local_busy){ 603 channel->local_busy = 0; 604 channel->send_supervisor_frame_receiver_ready_poll = 1; 605 l2cap_run(); 606 } 607 return ERROR_CODE_SUCCESS; 608 } 609 610 // Process-ReqSeq 611 static void l2cap_ertm_process_req_seq(l2cap_channel_t * l2cap_channel, uint8_t req_seq){ 612 int num_buffers_acked = 0; 613 l2cap_ertm_tx_packet_state_t * tx_state; 614 log_info("l2cap_ertm_process_req_seq: tx_read_index %u, tx_write_index %u, req_seq %u", l2cap_channel->tx_read_index, l2cap_channel->tx_write_index, req_seq); 615 while (1){ 616 617 // no unack packets left 618 if (l2cap_channel->unacked_frames == 0) { 619 // stop retransmission timer 620 l2cap_ertm_stop_retransmission_timer(l2cap_channel); 621 break; 622 } 623 624 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 625 // calc delta 626 int delta = (req_seq - tx_state->tx_seq) & 0x03f; 627 if (delta == 0) break; // all packets acknowledged 628 if (delta > l2cap_channel->remote_tx_window_size) break; 629 630 num_buffers_acked++; 631 l2cap_channel->unacked_frames--; 632 log_info("RR seq %u => packet with tx_seq %u done", req_seq, tx_state->tx_seq); 633 634 l2cap_channel->tx_read_index++; 635 if (l2cap_channel->tx_read_index >= l2cap_channel->num_rx_buffers){ 636 l2cap_channel->tx_read_index = 0; 637 } 638 } 639 640 if (num_buffers_acked){ 641 l2cap_ertm_notify_channel_can_send(l2cap_channel); 642 } 643 } 644 645 static l2cap_ertm_tx_packet_state_t * l2cap_ertm_get_tx_state(l2cap_channel_t * l2cap_channel, uint8_t tx_seq){ 646 int i; 647 for (i=0;i<l2cap_channel->num_tx_buffers;i++){ 648 l2cap_ertm_tx_packet_state_t * tx_state = &l2cap_channel->tx_packets_state[i]; 649 if (tx_state->tx_seq == tx_seq) return tx_state; 650 } 651 return NULL; 652 } 653 654 // @param delta number of frames in the future, >= 1 655 // @assumption size <= l2cap_channel->local_mps (checked in l2cap_acl_classic_handler) 656 static void l2cap_ertm_handle_out_of_sequence_sdu(l2cap_channel_t * l2cap_channel, l2cap_segmentation_and_reassembly_t sar, int delta, const uint8_t * payload, uint16_t size){ 657 log_info("Store SDU with delta %u", delta); 658 // get rx state for packet to store 659 int index = l2cap_channel->rx_store_index + delta - 1; 660 if (index > l2cap_channel->num_rx_buffers){ 661 index -= l2cap_channel->num_rx_buffers; 662 } 663 log_info("Index of packet to store %u", index); 664 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 665 // check if buffer is free 666 if (rx_state->valid){ 667 log_error("Packet buffer already used"); 668 return; 669 } 670 rx_state->valid = 1; 671 rx_state->sar = sar; 672 rx_state->len = size; 673 uint8_t * rx_buffer = &l2cap_channel->rx_packets_data[index]; 674 memcpy(rx_buffer, payload, size); 675 } 676 677 // @assumption size <= l2cap_channel->local_mps (checked in l2cap_acl_classic_handler) 678 static void l2cap_ertm_handle_in_sequence_sdu(l2cap_channel_t * l2cap_channel, l2cap_segmentation_and_reassembly_t sar, const uint8_t * payload, uint16_t size){ 679 uint16_t reassembly_sdu_length; 680 switch (sar){ 681 case L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU: 682 // assert total packet size <= our mtu 683 if (size > l2cap_channel->local_mtu) break; 684 // packet complete -> disapatch 685 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, (uint8_t*) payload, size); 686 break; 687 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 688 // read SDU len 689 reassembly_sdu_length = little_endian_read_16(payload, 0); 690 payload += 2; 691 size -= 2; 692 // assert reassembled size <= our mtu 693 if (reassembly_sdu_length > l2cap_channel->local_mtu) break; 694 // store start segment 695 l2cap_channel->reassembly_sdu_length = reassembly_sdu_length; 696 memcpy(&l2cap_channel->reassembly_buffer[0], payload, size); 697 l2cap_channel->reassembly_pos = size; 698 break; 699 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 700 // assert size of reassembled data <= our mtu 701 if (l2cap_channel->reassembly_pos + size > l2cap_channel->local_mtu) break; 702 // store continuation segment 703 memcpy(&l2cap_channel->reassembly_buffer[l2cap_channel->reassembly_pos], payload, size); 704 l2cap_channel->reassembly_pos += size; 705 break; 706 case L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU: 707 // assert size of reassembled data <= our mtu 708 if (l2cap_channel->reassembly_pos + size > l2cap_channel->local_mtu) break; 709 // store continuation segment 710 memcpy(&l2cap_channel->reassembly_buffer[l2cap_channel->reassembly_pos], payload, size); 711 l2cap_channel->reassembly_pos += size; 712 // assert size of reassembled data matches announced sdu length 713 if (l2cap_channel->reassembly_pos != l2cap_channel->reassembly_sdu_length) break; 714 // packet complete -> disapatch 715 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, l2cap_channel->reassembly_buffer, l2cap_channel->reassembly_pos); 716 l2cap_channel->reassembly_pos = 0; 717 break; 718 } 719 } 720 721 #endif 722 723 void l2cap_init(void){ 724 signaling_responses_pending = 0; 725 726 l2cap_channels = NULL; 727 728 #ifdef ENABLE_CLASSIC 729 l2cap_services = NULL; 730 require_security_level2_for_outgoing_sdp = 0; 731 732 // Setup Connectionless Channel 733 l2cap_fixed_channel_connectionless.local_cid = L2CAP_CID_CONNECTIONLESS_CHANNEL; 734 l2cap_fixed_channel_connectionless.channel_type = L2CAP_CHANNEL_TYPE_CONNECTIONLESS; 735 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_connectionless); 736 #endif 737 738 #ifdef ENABLE_LE_DATA_CHANNELS 739 l2cap_le_services = NULL; 740 #endif 741 742 #ifdef ENABLE_BLE 743 l2cap_event_packet_handler = NULL; 744 l2cap_le_custom_max_mtu = 0; 745 746 // Setup fixed ATT Channel 747 l2cap_fixed_channel_att.local_cid = L2CAP_CID_ATTRIBUTE_PROTOCOL; 748 l2cap_fixed_channel_att.channel_type = L2CAP_CHANNEL_TYPE_LE_FIXED; 749 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_att); 750 751 // Setup fixed SM Channel 752 l2cap_fixed_channel_sm.local_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 753 l2cap_fixed_channel_sm.channel_type = L2CAP_CHANNEL_TYPE_LE_FIXED; 754 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_sm); 755 #endif 756 757 // 758 // register callback with HCI 759 // 760 hci_event_callback_registration.callback = &l2cap_hci_event_handler; 761 hci_add_event_handler(&hci_event_callback_registration); 762 763 hci_register_acl_packet_handler(&l2cap_acl_handler); 764 765 #ifdef ENABLE_CLASSIC 766 gap_connectable_control(0); // no services yet 767 #endif 768 } 769 770 void l2cap_register_packet_handler(void (*handler)(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 771 #ifdef ENABLE_BLE 772 l2cap_event_packet_handler = handler; 773 #else 774 UNUSED(handler); // ok: no code 775 #endif 776 } 777 778 void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t channel_id){ 779 UNUSED(con_handle); // ok: there is no con handle 780 781 l2cap_fixed_channel_t * channel = l2cap_fixed_channel_for_channel_id(channel_id); 782 if (!channel) return; 783 channel->waiting_for_can_send_now = 1; 784 l2cap_notify_channel_can_send(); 785 } 786 787 int l2cap_can_send_fixed_channel_packet_now(hci_con_handle_t con_handle, uint16_t channel_id){ 788 UNUSED(channel_id); // ok: only depends on Controller LE buffers 789 790 return hci_can_send_acl_packet_now(con_handle); 791 } 792 793 uint8_t *l2cap_get_outgoing_buffer(void){ 794 return hci_get_outgoing_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes 795 } 796 797 int l2cap_reserve_packet_buffer(void){ 798 return hci_reserve_packet_buffer(); 799 } 800 801 void l2cap_release_packet_buffer(void){ 802 hci_release_packet_buffer(); 803 } 804 805 static void l2cap_setup_header(uint8_t * acl_buffer, hci_con_handle_t con_handle, uint8_t packet_boundary, uint16_t remote_cid, uint16_t len){ 806 // 0 - Connection handle : PB=pb : BC=00 807 little_endian_store_16(acl_buffer, 0, con_handle | (packet_boundary << 12) | (0 << 14)); 808 // 2 - ACL length 809 little_endian_store_16(acl_buffer, 2, len + 4); 810 // 4 - L2CAP packet length 811 little_endian_store_16(acl_buffer, 4, len + 0); 812 // 6 - L2CAP channel DEST 813 little_endian_store_16(acl_buffer, 6, remote_cid); 814 } 815 816 // assumption - only on LE connections 817 int l2cap_send_prepared_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint16_t len){ 818 819 if (!hci_is_packet_buffer_reserved()){ 820 log_error("l2cap_send_prepared_connectionless called without reserving packet first"); 821 return BTSTACK_ACL_BUFFERS_FULL; 822 } 823 824 if (!hci_can_send_prepared_acl_packet_now(con_handle)){ 825 log_info("l2cap_send_prepared_connectionless handle 0x%02x, cid 0x%02x, cannot send", con_handle, cid); 826 return BTSTACK_ACL_BUFFERS_FULL; 827 } 828 829 log_debug("l2cap_send_prepared_connectionless handle %u, cid 0x%02x", con_handle, cid); 830 831 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 832 l2cap_setup_header(acl_buffer, con_handle, 0, cid, len); 833 // send 834 return hci_send_acl_packet_buffer(len+8); 835 } 836 837 // assumption - only on LE connections 838 int l2cap_send_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint8_t *data, uint16_t len){ 839 840 if (!hci_can_send_acl_packet_now(con_handle)){ 841 log_info("l2cap_send cid 0x%02x, cannot send", cid); 842 return BTSTACK_ACL_BUFFERS_FULL; 843 } 844 845 hci_reserve_packet_buffer(); 846 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 847 848 memcpy(&acl_buffer[8], data, len); 849 850 return l2cap_send_prepared_connectionless(con_handle, cid, len); 851 } 852 853 static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel) { 854 log_debug("L2CAP_EVENT_CHANNEL_CAN_SEND_NOW local_cid 0x%x", channel); 855 uint8_t event[4]; 856 event[0] = L2CAP_EVENT_CAN_SEND_NOW; 857 event[1] = sizeof(event) - 2; 858 little_endian_store_16(event, 2, channel); 859 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 860 packet_handler(HCI_EVENT_PACKET, channel, event, sizeof(event)); 861 } 862 863 #ifdef L2CAP_USES_CHANNELS 864 static void l2cap_dispatch_to_channel(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 865 (* (channel->packet_handler))(type, channel->local_cid, data, size); 866 } 867 868 static void l2cap_emit_simple_event_with_cid(l2cap_channel_t * channel, uint8_t event_code){ 869 uint8_t event[4]; 870 event[0] = event_code; 871 event[1] = sizeof(event) - 2; 872 little_endian_store_16(event, 2, channel->local_cid); 873 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 874 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 875 } 876 #endif 877 878 #ifdef ENABLE_CLASSIC 879 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 880 log_info("L2CAP_EVENT_CHANNEL_OPENED status 0x%x addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x local_mtu %u, remote_mtu %u, flush_timeout %u", 881 status, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, 882 channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu, channel->flush_timeout); 883 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 884 log_info("ERTM mode %u, fcs enabled %u", channel->mode, channel->fcs_option); 885 #endif 886 uint8_t event[24]; 887 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 888 event[1] = sizeof(event) - 2; 889 event[2] = status; 890 reverse_bd_addr(channel->address, &event[3]); 891 little_endian_store_16(event, 9, channel->con_handle); 892 little_endian_store_16(event, 11, channel->psm); 893 little_endian_store_16(event, 13, channel->local_cid); 894 little_endian_store_16(event, 15, channel->remote_cid); 895 little_endian_store_16(event, 17, channel->local_mtu); 896 little_endian_store_16(event, 19, channel->remote_mtu); 897 little_endian_store_16(event, 21, channel->flush_timeout); 898 event[23] = channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING ? 1 : 0; 899 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 900 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 901 } 902 903 static void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 904 log_info("L2CAP_EVENT_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid); 905 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_CHANNEL_CLOSED); 906 } 907 908 static void l2cap_emit_incoming_connection(l2cap_channel_t *channel) { 909 log_info("L2CAP_EVENT_INCOMING_CONNECTION addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x", 910 bd_addr_to_str(channel->address), channel->con_handle, channel->psm, channel->local_cid, channel->remote_cid); 911 uint8_t event[16]; 912 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 913 event[1] = sizeof(event) - 2; 914 reverse_bd_addr(channel->address, &event[2]); 915 little_endian_store_16(event, 8, channel->con_handle); 916 little_endian_store_16(event, 10, channel->psm); 917 little_endian_store_16(event, 12, channel->local_cid); 918 little_endian_store_16(event, 14, channel->remote_cid); 919 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 920 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 921 } 922 #endif 923 924 static l2cap_fixed_channel_t * l2cap_channel_item_by_cid(uint16_t cid){ 925 btstack_linked_list_iterator_t it; 926 btstack_linked_list_iterator_init(&it, &l2cap_channels); 927 while (btstack_linked_list_iterator_has_next(&it)){ 928 l2cap_fixed_channel_t * channel = (l2cap_fixed_channel_t*) btstack_linked_list_iterator_next(&it); 929 if (channel->local_cid == cid) { 930 return channel; 931 } 932 } 933 return NULL; 934 } 935 936 // used for fixed channels in LE (ATT/SM) and Classic (Connectionless Channel). CID < 0x04 937 static l2cap_fixed_channel_t * l2cap_fixed_channel_for_channel_id(uint16_t local_cid){ 938 if (local_cid >= 0x40) return NULL; 939 return (l2cap_fixed_channel_t*) l2cap_channel_item_by_cid(local_cid); 940 } 941 942 // used for Classic Channels + LE Data Channels. local_cid >= 0x40 943 #ifdef L2CAP_USES_CHANNELS 944 static l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 945 if (local_cid < 0x40) return NULL; 946 return (l2cap_channel_t*) l2cap_channel_item_by_cid(local_cid); 947 } 948 949 void l2cap_request_can_send_now_event(uint16_t local_cid){ 950 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 951 if (!channel) return; 952 channel->waiting_for_can_send_now = 1; 953 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 954 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 955 l2cap_ertm_notify_channel_can_send(channel); 956 return; 957 } 958 #endif 959 l2cap_notify_channel_can_send(); 960 } 961 962 int l2cap_can_send_packet_now(uint16_t local_cid){ 963 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 964 if (!channel) return 0; 965 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 966 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 967 return l2cap_ertm_can_store_packet_now(channel); 968 } 969 #endif 970 return hci_can_send_acl_packet_now(channel->con_handle); 971 } 972 973 int l2cap_can_send_prepared_packet_now(uint16_t local_cid){ 974 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 975 if (!channel) return 0; 976 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 977 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 978 return 0; 979 } 980 #endif 981 return hci_can_send_prepared_acl_packet_now(channel->con_handle); 982 } 983 984 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 985 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 986 if (channel) { 987 return channel->remote_mtu; 988 } 989 return 0; 990 } 991 #endif 992 993 #ifdef L2CAP_USES_CHANNELS 994 static int l2cap_is_dynamic_channel_type(l2cap_channel_type_t channel_type){ 995 switch (channel_type){ 996 case L2CAP_CHANNEL_TYPE_CLASSIC: 997 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 998 return 1; 999 default: 1000 return 0; 1001 } 1002 } 1003 #endif 1004 1005 static int l2cap_is_le_channel_type(l2cap_channel_type_t channel_type){ 1006 switch (channel_type){ 1007 case L2CAP_CHANNEL_TYPE_LE_FIXED: 1008 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 1009 return 1; 1010 default: 1011 return 0; 1012 } 1013 } 1014 1015 #ifdef ENABLE_CLASSIC 1016 // RTX Timer only exist for dynamic channels 1017 static l2cap_channel_t * l2cap_channel_for_rtx_timer(btstack_timer_source_t * ts){ 1018 btstack_linked_list_iterator_t it; 1019 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1020 while (btstack_linked_list_iterator_has_next(&it)){ 1021 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1022 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 1023 if (&channel->rtx == ts) { 1024 return channel; 1025 } 1026 } 1027 return NULL; 1028 } 1029 1030 static void l2cap_rtx_timeout(btstack_timer_source_t * ts){ 1031 l2cap_channel_t * channel = l2cap_channel_for_rtx_timer(ts); 1032 if (!channel) return; 1033 1034 log_info("l2cap_rtx_timeout for local cid 0x%02x", channel->local_cid); 1035 1036 // "When terminating the channel, it is not necessary to send a L2CAP_DisconnectReq 1037 // and enter WAIT_DISCONNECT state. Channels can be transitioned directly to the CLOSED state." 1038 // notify client 1039 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_RTX_TIMEOUT); 1040 1041 // discard channel 1042 // no need to stop timer here, it is removed from list during timer callback 1043 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1044 btstack_memory_l2cap_channel_free(channel); 1045 } 1046 1047 #endif 1048 1049 #ifdef L2CAP_USES_CHANNELS 1050 static void l2cap_stop_rtx(l2cap_channel_t * channel){ 1051 log_info("l2cap_stop_rtx for local cid 0x%02x", channel->local_cid); 1052 btstack_run_loop_remove_timer(&channel->rtx); 1053 } 1054 #endif 1055 1056 #ifdef ENABLE_CLASSIC 1057 1058 static void l2cap_start_rtx(l2cap_channel_t * channel){ 1059 l2cap_stop_rtx(channel); 1060 log_info("l2cap_start_rtx for local cid 0x%02x", channel->local_cid); 1061 btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout); 1062 btstack_run_loop_set_timer(&channel->rtx, L2CAP_RTX_TIMEOUT_MS); 1063 btstack_run_loop_add_timer(&channel->rtx); 1064 } 1065 1066 static void l2cap_start_ertx(l2cap_channel_t * channel){ 1067 log_info("l2cap_start_ertx for local cid 0x%02x", channel->local_cid); 1068 l2cap_stop_rtx(channel); 1069 btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout); 1070 btstack_run_loop_set_timer(&channel->rtx, L2CAP_ERTX_TIMEOUT_MS); 1071 btstack_run_loop_add_timer(&channel->rtx); 1072 } 1073 1074 void l2cap_require_security_level_2_for_outgoing_sdp(void){ 1075 require_security_level2_for_outgoing_sdp = 1; 1076 } 1077 1078 static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm){ 1079 return (psm == BLUETOOTH_PROTOCOL_SDP) && (!require_security_level2_for_outgoing_sdp); 1080 } 1081 1082 static int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, int identifier, ...){ 1083 if (!hci_can_send_acl_packet_now(handle)){ 1084 log_info("l2cap_send_signaling_packet, cannot send"); 1085 return BTSTACK_ACL_BUFFERS_FULL; 1086 } 1087 1088 // log_info("l2cap_send_signaling_packet type %u", cmd); 1089 hci_reserve_packet_buffer(); 1090 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1091 va_list argptr; 1092 va_start(argptr, identifier); 1093 uint16_t len = l2cap_create_signaling_classic(acl_buffer, handle, cmd, identifier, argptr); 1094 va_end(argptr); 1095 // log_info("l2cap_send_signaling_packet con %u!", handle); 1096 return hci_send_acl_packet_buffer(len); 1097 } 1098 1099 // assumption - only on Classic connections 1100 int l2cap_send_prepared(uint16_t local_cid, uint16_t len){ 1101 1102 if (!hci_is_packet_buffer_reserved()){ 1103 log_error("l2cap_send_prepared called without reserving packet first"); 1104 return BTSTACK_ACL_BUFFERS_FULL; 1105 } 1106 1107 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1108 if (!channel) { 1109 log_error("l2cap_send_prepared no channel for cid 0x%02x", local_cid); 1110 return -1; // TODO: define error 1111 } 1112 1113 if (!hci_can_send_prepared_acl_packet_now(channel->con_handle)){ 1114 log_info("l2cap_send_prepared cid 0x%02x, cannot send", local_cid); 1115 return BTSTACK_ACL_BUFFERS_FULL; 1116 } 1117 1118 log_debug("l2cap_send_prepared cid 0x%02x, handle %u, 1 credit used", local_cid, channel->con_handle); 1119 1120 int fcs_size = 0; 1121 1122 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1123 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION && channel->fcs_option){ 1124 fcs_size = 2; 1125 } 1126 #endif 1127 1128 // set non-flushable packet boundary flag if supported on Controller 1129 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1130 uint8_t packet_boundary_flag = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02; 1131 l2cap_setup_header(acl_buffer, channel->con_handle, packet_boundary_flag, channel->remote_cid, len + fcs_size); 1132 1133 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1134 if (fcs_size){ 1135 // calculate FCS over l2cap data 1136 uint16_t fcs = crc16_calc(acl_buffer + 4, 4 + len); 1137 log_info("I-Frame: fcs 0x%04x", fcs); 1138 little_endian_store_16(acl_buffer, 8 + len, fcs); 1139 } 1140 #endif 1141 1142 // send 1143 return hci_send_acl_packet_buffer(len+8+fcs_size); 1144 } 1145 1146 // assumption - only on Classic connections 1147 int l2cap_send(uint16_t local_cid, uint8_t *data, uint16_t len){ 1148 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1149 if (!channel) { 1150 log_error("l2cap_send no channel for cid 0x%02x", local_cid); 1151 return -1; // TODO: define error 1152 } 1153 1154 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1155 // send in ERTM 1156 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1157 return l2cap_ertm_send(channel, data, len); 1158 } 1159 #endif 1160 1161 if (len > channel->remote_mtu){ 1162 log_error("l2cap_send cid 0x%02x, data length exceeds remote MTU.", local_cid); 1163 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 1164 } 1165 1166 if (!hci_can_send_acl_packet_now(channel->con_handle)){ 1167 log_info("l2cap_send cid 0x%02x, cannot send", local_cid); 1168 return BTSTACK_ACL_BUFFERS_FULL; 1169 } 1170 1171 hci_reserve_packet_buffer(); 1172 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1173 memcpy(&acl_buffer[8], data, len); 1174 return l2cap_send_prepared(local_cid, len); 1175 } 1176 1177 int l2cap_send_echo_request(hci_con_handle_t con_handle, uint8_t *data, uint16_t len){ 1178 return l2cap_send_signaling_packet(con_handle, ECHO_REQUEST, 0x77, len, data); 1179 } 1180 1181 static inline void channelStateVarSetFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){ 1182 channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var | flag); 1183 } 1184 1185 static inline void channelStateVarClearFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){ 1186 channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var & ~flag); 1187 } 1188 #endif 1189 1190 1191 #ifdef ENABLE_BLE 1192 static int l2cap_send_le_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, int identifier, ...){ 1193 1194 if (!hci_can_send_acl_packet_now(handle)){ 1195 log_info("l2cap_send_le_signaling_packet, cannot send"); 1196 return BTSTACK_ACL_BUFFERS_FULL; 1197 } 1198 1199 // log_info("l2cap_send_le_signaling_packet type %u", cmd); 1200 hci_reserve_packet_buffer(); 1201 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1202 va_list argptr; 1203 va_start(argptr, identifier); 1204 uint16_t len = l2cap_create_signaling_le(acl_buffer, handle, cmd, identifier, argptr); 1205 va_end(argptr); 1206 // log_info("l2cap_send_le_signaling_packet con %u!", handle); 1207 return hci_send_acl_packet_buffer(len); 1208 } 1209 #endif 1210 1211 uint16_t l2cap_max_mtu(void){ 1212 return HCI_ACL_PAYLOAD_SIZE - L2CAP_HEADER_SIZE; 1213 } 1214 1215 uint16_t l2cap_max_le_mtu(void){ 1216 if (l2cap_le_custom_max_mtu != 0) return l2cap_le_custom_max_mtu; 1217 return l2cap_max_mtu(); 1218 } 1219 1220 void l2cap_set_max_le_mtu(uint16_t max_mtu){ 1221 if (max_mtu < l2cap_max_mtu()){ 1222 l2cap_le_custom_max_mtu = max_mtu; 1223 } 1224 } 1225 1226 #ifdef ENABLE_CLASSIC 1227 1228 static uint16_t l2cap_setup_options_mtu(uint8_t * config_options, uint16_t mtu){ 1229 config_options[0] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; // MTU 1230 config_options[1] = 2; // len param 1231 little_endian_store_16(config_options, 2, mtu); 1232 return 4; 1233 } 1234 1235 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1236 static int l2cap_ertm_mode(l2cap_channel_t * channel){ 1237 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 1238 return ((connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE) 1239 && (connection->l2cap_state.extended_feature_mask & 0x08)); 1240 } 1241 #endif 1242 1243 static uint16_t l2cap_setup_options_request(l2cap_channel_t * channel, uint8_t * config_options){ 1244 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1245 // use ERTM options if supported 1246 if (l2cap_ertm_mode(channel)){ 1247 return l2cap_setup_options_ertm_request(channel, config_options); 1248 } 1249 #endif 1250 uint16_t mtu = channel->local_mtu; 1251 return l2cap_setup_options_mtu(config_options, mtu); 1252 } 1253 1254 static uint16_t l2cap_setup_options_response(l2cap_channel_t * channel, uint8_t * config_options){ 1255 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1256 // use ERTM options if supported 1257 if (l2cap_ertm_mode(channel)){ 1258 return l2cap_setup_options_ertm_response(channel, config_options); 1259 } 1260 #endif 1261 uint16_t mtu = btstack_min(channel->local_mtu, channel->remote_mtu); 1262 return l2cap_setup_options_mtu(config_options, mtu); 1263 } 1264 1265 static uint32_t l2cap_extended_features_mask(void){ 1266 // extended features request supported, features: fixed channels, unicast connectionless data reception 1267 uint32_t features = 0x280; 1268 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1269 features |= 0x0028; 1270 #endif 1271 return features; 1272 } 1273 #endif 1274 1275 // MARK: L2CAP_RUN 1276 // process outstanding signaling tasks 1277 static void l2cap_run(void){ 1278 1279 // log_info("l2cap_run: entered"); 1280 1281 // check pending signaling responses 1282 while (signaling_responses_pending){ 1283 1284 hci_con_handle_t handle = signaling_responses[0].handle; 1285 1286 if (!hci_can_send_acl_packet_now(handle)) break; 1287 1288 uint8_t sig_id = signaling_responses[0].sig_id; 1289 uint8_t response_code = signaling_responses[0].code; 1290 uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST, COMMAND_REJECT 1291 #ifdef ENABLE_CLASSIC 1292 uint16_t info_type = signaling_responses[0].data; // INFORMATION_REQUEST 1293 uint16_t source_cid = signaling_responses[0].cid; // CONNECTION_REQUEST 1294 #endif 1295 1296 // remove first item before sending (to avoid sending response mutliple times) 1297 signaling_responses_pending--; 1298 int i; 1299 for (i=0; i < signaling_responses_pending; i++){ 1300 memcpy(&signaling_responses[i], &signaling_responses[i+1], sizeof(l2cap_signaling_response_t)); 1301 } 1302 1303 switch (response_code){ 1304 #ifdef ENABLE_CLASSIC 1305 case CONNECTION_REQUEST: 1306 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, source_cid, 0, result, 0); 1307 // also disconnect if result is 0x0003 - security blocked 1308 if (result == 0x0003){ 1309 hci_disconnect_security_block(handle); 1310 } 1311 break; 1312 case ECHO_REQUEST: 1313 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 1314 break; 1315 case INFORMATION_REQUEST: 1316 switch (info_type){ 1317 case L2CAP_INFO_TYPE_CONNECTIONLESS_MTU: { 1318 uint16_t connectionless_mtu = hci_max_acl_data_packet_length(); 1319 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, sizeof(connectionless_mtu), &connectionless_mtu); 1320 } 1321 break; 1322 case L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED: { 1323 uint32_t features = l2cap_extended_features_mask(); 1324 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, sizeof(features), &features); 1325 } 1326 break; 1327 case L2CAP_INFO_TYPE_FIXED_CHANNELS_SUPPORTED: { 1328 uint8_t map[8]; 1329 memset(map, 0, 8); 1330 map[0] = 0x06; // L2CAP Signaling Channel (0x02) + Connectionless reception (0x04) 1331 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, sizeof(map), &map); 1332 } 1333 break; 1334 default: 1335 // all other types are not supported 1336 l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 1, 0, NULL); 1337 break; 1338 } 1339 break; 1340 case COMMAND_REJECT: 1341 l2cap_send_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL); 1342 break; 1343 #endif 1344 #ifdef ENABLE_BLE 1345 case LE_CREDIT_BASED_CONNECTION_REQUEST: 1346 l2cap_send_le_signaling_packet(handle, LE_CREDIT_BASED_CONNECTION_RESPONSE, sig_id, 0, 0, 0, 0, result); 1347 break; 1348 case COMMAND_REJECT_LE: 1349 l2cap_send_le_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL); 1350 break; 1351 #endif 1352 default: 1353 // should not happen 1354 break; 1355 } 1356 } 1357 1358 #if defined(ENABLE_CLASSIC) || defined(ENABLE_BLE) 1359 btstack_linked_list_iterator_t it; 1360 #endif 1361 1362 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1363 // send l2cap information request if neccessary 1364 hci_connections_get_iterator(&it); 1365 while(btstack_linked_list_iterator_has_next(&it)){ 1366 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1367 if (connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST){ 1368 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W4_EXTENDED_FEATURE_RESPONSE; 1369 // send information request for extended features 1370 uint8_t sig_id = l2cap_next_sig_id(); 1371 uint8_t info_type = L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED; 1372 l2cap_send_signaling_packet(connection->con_handle, INFORMATION_REQUEST, sig_id, info_type); 1373 return; 1374 } 1375 } 1376 #endif 1377 1378 #ifdef ENABLE_CLASSIC 1379 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1380 uint8_t config_options[18]; 1381 #else 1382 uint8_t config_options[10]; 1383 #endif 1384 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1385 while (btstack_linked_list_iterator_has_next(&it)){ 1386 1387 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1388 1389 if (channel->channel_type != L2CAP_CHANNEL_TYPE_CLASSIC) continue; 1390 1391 // log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var); 1392 switch (channel->state){ 1393 1394 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 1395 case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT: 1396 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1397 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND) { 1398 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND); 1399 l2cap_send_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 1, 0); 1400 } 1401 break; 1402 1403 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 1404 if (!hci_can_send_command_packet_now()) break; 1405 // send connection request - set state first 1406 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 1407 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 1408 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1); 1409 break; 1410 1411 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 1412 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1413 channel->state = L2CAP_STATE_INVALID; 1414 l2cap_send_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, channel->reason, 0); 1415 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 1416 l2cap_stop_rtx(channel); 1417 btstack_linked_list_iterator_remove(&it); 1418 btstack_memory_l2cap_channel_free(channel); 1419 break; 1420 1421 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 1422 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1423 channel->state = L2CAP_STATE_CONFIG; 1424 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 1425 l2cap_send_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0); 1426 break; 1427 1428 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 1429 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1430 // success, start l2cap handshake 1431 channel->local_sig_id = l2cap_next_sig_id(); 1432 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 1433 l2cap_send_signaling_packet( channel->con_handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid); 1434 l2cap_start_rtx(channel); 1435 break; 1436 1437 case L2CAP_STATE_CONFIG: 1438 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1439 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 1440 uint16_t flags = 0; 1441 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 1442 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT) { 1443 flags = 1; 1444 } else { 1445 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1446 } 1447 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID){ 1448 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1449 l2cap_send_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_UNKNOWN_OPTIONS, 0, NULL); 1450 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1451 } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED){ 1452 channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED); 1453 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1454 uint16_t options_size = l2cap_setup_options_response(channel, config_options); 1455 l2cap_send_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS, options_size, &config_options); 1456 #endif 1457 } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU){ 1458 channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 1459 uint16_t options_size = l2cap_setup_options_response(channel, config_options); 1460 l2cap_send_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_SUCCESS, options_size, &config_options); 1461 } else { 1462 l2cap_send_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_SUCCESS, 0, NULL); 1463 } 1464 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT); 1465 } 1466 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 1467 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 1468 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ); 1469 channel->local_sig_id = l2cap_next_sig_id(); 1470 uint16_t options_size = l2cap_setup_options_request(channel, config_options); 1471 l2cap_send_signaling_packet(channel->con_handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, options_size, &config_options); 1472 l2cap_start_rtx(channel); 1473 } 1474 if (l2cap_channel_ready_for_open(channel)){ 1475 channel->state = L2CAP_STATE_OPEN; 1476 l2cap_emit_channel_opened(channel, 0); // success 1477 } 1478 break; 1479 1480 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 1481 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1482 channel->state = L2CAP_STATE_INVALID; 1483 l2cap_send_signaling_packet( channel->con_handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 1484 // we don't start an RTX timer for a disconnect - there's no point in closing the channel if the other side doesn't respond :) 1485 l2cap_finialize_channel_close(channel); // -- remove from list 1486 break; 1487 1488 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 1489 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1490 channel->local_sig_id = l2cap_next_sig_id(); 1491 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 1492 l2cap_send_signaling_packet( channel->con_handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 1493 break; 1494 default: 1495 break; 1496 } 1497 1498 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1499 // send s-frame to acknowledge received packets 1500 if (!hci_can_send_acl_packet_now(channel->con_handle)) continue; 1501 1502 if (channel->tx_send_index != channel->tx_write_index){ 1503 // check remote tx window 1504 log_info("unacknowledged_packets %u, remote tx window size %u", channel->unacked_frames, channel->remote_tx_window_size); 1505 if (channel->unacked_frames < channel->remote_tx_window_size){ 1506 channel->unacked_frames++; 1507 int index = channel->tx_send_index; 1508 channel->tx_send_index++; 1509 if (channel->tx_send_index >= channel->num_tx_buffers){ 1510 channel->tx_send_index = 0; 1511 } 1512 l2cap_ertm_send_information_frame(channel, index, 0); // final = 0 1513 continue; 1514 } 1515 } 1516 1517 if (channel->send_supervisor_frame_receiver_ready){ 1518 channel->send_supervisor_frame_receiver_ready = 0; 1519 log_info("Send S-Frame: RR %u, final %u", channel->req_seq, channel->set_final_bit_after_packet_with_poll_bit_set); 1520 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY, 0, channel->set_final_bit_after_packet_with_poll_bit_set, channel->req_seq); 1521 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1522 l2cap_ertm_send_supervisor_frame(channel, control); 1523 continue; 1524 } 1525 if (channel->send_supervisor_frame_receiver_ready_poll){ 1526 channel->send_supervisor_frame_receiver_ready_poll = 0; 1527 log_info("Send S-Frame: RR %u with poll=1 ", channel->req_seq); 1528 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY, 1, 0, channel->req_seq); 1529 l2cap_ertm_send_supervisor_frame(channel, control); 1530 continue; 1531 } 1532 if (channel->send_supervisor_frame_receiver_not_ready){ 1533 channel->send_supervisor_frame_receiver_not_ready = 0; 1534 log_info("Send S-Frame: RNR %u", channel->req_seq); 1535 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY, 0, 0, channel->req_seq); 1536 l2cap_ertm_send_supervisor_frame(channel, control); 1537 continue; 1538 } 1539 if (channel->send_supervisor_frame_reject){ 1540 channel->send_supervisor_frame_reject = 0; 1541 log_info("Send S-Frame: REJ %u", channel->req_seq); 1542 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT, 0, 0, channel->req_seq); 1543 l2cap_ertm_send_supervisor_frame(channel, control); 1544 continue; 1545 } 1546 if (channel->send_supervisor_frame_selective_reject){ 1547 channel->send_supervisor_frame_selective_reject = 0; 1548 log_info("Send S-Frame: SREJ %u", channel->expected_tx_seq); 1549 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT, 0, channel->set_final_bit_after_packet_with_poll_bit_set, channel->expected_tx_seq); 1550 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1551 l2cap_ertm_send_supervisor_frame(channel, control); 1552 continue; 1553 } 1554 1555 if (channel->srej_active){ 1556 int i; 1557 for (i=0;i<channel->num_tx_buffers;i++){ 1558 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[i]; 1559 if (tx_state->retransmission_requested) { 1560 tx_state->retransmission_requested = 0; 1561 uint8_t final = channel->set_final_bit_after_packet_with_poll_bit_set; 1562 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1563 l2cap_ertm_send_information_frame(channel, i, final); 1564 break; 1565 } 1566 } 1567 if (i == channel->num_tx_buffers){ 1568 // no retransmission request found 1569 channel->srej_active = 0; 1570 } else { 1571 // packet was sent 1572 continue; 1573 } 1574 } 1575 #endif 1576 1577 } 1578 #endif 1579 1580 #ifdef ENABLE_LE_DATA_CHANNELS 1581 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1582 while (btstack_linked_list_iterator_has_next(&it)){ 1583 uint8_t * acl_buffer; 1584 uint8_t * l2cap_payload; 1585 uint16_t pos; 1586 uint16_t payload_size; 1587 uint16_t mps; 1588 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1589 1590 if (channel->channel_type != L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL) continue; 1591 1592 // log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var); 1593 switch (channel->state){ 1594 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST: 1595 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1596 channel->state = L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE; 1597 // le psm, source cid, mtu, mps, initial credits 1598 channel->local_sig_id = l2cap_next_sig_id(); 1599 channel->credits_incoming = channel->new_credits_incoming; 1600 channel->new_credits_incoming = 0; 1601 mps = btstack_min(l2cap_max_le_mtu(), channel->local_mtu); 1602 l2cap_send_le_signaling_packet( channel->con_handle, LE_CREDIT_BASED_CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid, channel->local_mtu, mps, channel->credits_incoming); 1603 break; 1604 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT: 1605 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1606 // TODO: support larger MPS 1607 channel->state = L2CAP_STATE_OPEN; 1608 channel->credits_incoming = channel->new_credits_incoming; 1609 channel->new_credits_incoming = 0; 1610 mps = btstack_min(l2cap_max_le_mtu(), channel->local_mtu); 1611 l2cap_send_le_signaling_packet(channel->con_handle, LE_CREDIT_BASED_CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->local_mtu, mps, channel->credits_incoming, 0); 1612 // notify client 1613 l2cap_emit_le_channel_opened(channel, 0); 1614 break; 1615 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE: 1616 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1617 channel->state = L2CAP_STATE_INVALID; 1618 l2cap_send_le_signaling_packet(channel->con_handle, LE_CREDIT_BASED_CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, 0, 0, channel->reason); 1619 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 1620 l2cap_stop_rtx(channel); 1621 btstack_linked_list_iterator_remove(&it); 1622 btstack_memory_l2cap_channel_free(channel); 1623 break; 1624 case L2CAP_STATE_OPEN: 1625 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1626 1627 // send credits 1628 if (channel->new_credits_incoming){ 1629 log_info("l2cap: sending %u credits", channel->new_credits_incoming); 1630 channel->local_sig_id = l2cap_next_sig_id(); 1631 uint16_t new_credits = channel->new_credits_incoming; 1632 channel->new_credits_incoming = 0; 1633 channel->credits_incoming += new_credits; 1634 l2cap_send_le_signaling_packet(channel->con_handle, LE_FLOW_CONTROL_CREDIT, channel->local_sig_id, channel->remote_cid, new_credits); 1635 break; 1636 } 1637 1638 // send data 1639 if (!channel->send_sdu_buffer) break; 1640 if (!channel->credits_outgoing) break; 1641 1642 // send part of SDU 1643 hci_reserve_packet_buffer(); 1644 acl_buffer = hci_get_outgoing_packet_buffer(); 1645 l2cap_payload = acl_buffer + 8; 1646 pos = 0; 1647 if (!channel->send_sdu_pos){ 1648 // store SDU len 1649 channel->send_sdu_pos += 2; 1650 little_endian_store_16(l2cap_payload, pos, channel->send_sdu_len); 1651 pos += 2; 1652 } 1653 payload_size = btstack_min(channel->send_sdu_len + 2 - channel->send_sdu_pos, channel->remote_mps - pos); 1654 log_info("len %u, pos %u => payload %u, credits %u", channel->send_sdu_len, channel->send_sdu_pos, payload_size, channel->credits_outgoing); 1655 memcpy(&l2cap_payload[pos], &channel->send_sdu_buffer[channel->send_sdu_pos-2], payload_size); // -2 for virtual SDU len 1656 pos += payload_size; 1657 channel->send_sdu_pos += payload_size; 1658 l2cap_setup_header(acl_buffer, channel->con_handle, 0, channel->remote_cid, pos); 1659 // done 1660 1661 channel->credits_outgoing--; 1662 1663 if (channel->send_sdu_pos >= channel->send_sdu_len + 2){ 1664 channel->send_sdu_buffer = NULL; 1665 // send done event 1666 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_PACKET_SENT); 1667 // inform about can send now 1668 l2cap_le_notify_channel_can_send(channel); 1669 } 1670 hci_send_acl_packet_buffer(8 + pos); 1671 break; 1672 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 1673 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1674 channel->local_sig_id = l2cap_next_sig_id(); 1675 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 1676 l2cap_send_le_signaling_packet( channel->con_handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 1677 break; 1678 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 1679 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1680 channel->state = L2CAP_STATE_INVALID; 1681 l2cap_send_le_signaling_packet( channel->con_handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 1682 l2cap_le_finialize_channel_close(channel); // -- remove from list 1683 break; 1684 default: 1685 break; 1686 } 1687 } 1688 #endif 1689 1690 #ifdef ENABLE_BLE 1691 // send l2cap con paramter update if necessary 1692 hci_connections_get_iterator(&it); 1693 while(btstack_linked_list_iterator_has_next(&it)){ 1694 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1695 if (connection->address_type != BD_ADDR_TYPE_LE_PUBLIC && connection->address_type != BD_ADDR_TYPE_LE_RANDOM) continue; 1696 if (!hci_can_send_acl_packet_now(connection->con_handle)) continue; 1697 switch (connection->le_con_parameter_update_state){ 1698 case CON_PARAMETER_UPDATE_SEND_REQUEST: 1699 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE; 1700 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_REQUEST, connection->le_con_param_update_identifier, 1701 connection->le_conn_interval_min, connection->le_conn_interval_max, connection->le_conn_latency, connection->le_supervision_timeout); 1702 break; 1703 case CON_PARAMETER_UPDATE_SEND_RESPONSE: 1704 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_CHANGE_HCI_CON_PARAMETERS; 1705 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 0); 1706 break; 1707 case CON_PARAMETER_UPDATE_DENY: 1708 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE; 1709 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 1); 1710 break; 1711 default: 1712 break; 1713 } 1714 } 1715 #endif 1716 1717 // log_info("l2cap_run: exit"); 1718 } 1719 1720 #ifdef ENABLE_CLASSIC 1721 static void l2cap_handle_connection_complete(hci_con_handle_t con_handle, l2cap_channel_t * channel){ 1722 if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) { 1723 log_info("l2cap_handle_connection_complete expected state"); 1724 // success, start l2cap handshake 1725 channel->con_handle = con_handle; 1726 // check remote SSP feature first 1727 channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES; 1728 } 1729 } 1730 1731 static void l2cap_ready_to_connect(l2cap_channel_t * channel){ 1732 1733 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1734 // assumption: outgoing connection 1735 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 1736 if (connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_IDLE){ 1737 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 1738 channel->state = L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES; 1739 return; 1740 } 1741 #endif 1742 1743 // fine, go ahead 1744 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 1745 } 1746 1747 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){ 1748 if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return; 1749 1750 // we have been waiting for remote supported features, if both support SSP, 1751 log_info("l2cap received remote supported features, sec_level_0_allowed for psm %u = %u", channel->psm, l2cap_security_level_0_allowed_for_PSM(channel->psm)); 1752 if (gap_ssp_supported_on_both_sides(channel->con_handle) && !l2cap_security_level_0_allowed_for_PSM(channel->psm)){ 1753 // request security level 2 1754 channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE; 1755 channel->required_security_level = LEVEL_2; 1756 gap_request_security_level(channel->con_handle, LEVEL_2); 1757 return; 1758 } 1759 1760 l2cap_ready_to_connect(channel); 1761 } 1762 #endif 1763 1764 #ifdef L2CAP_USES_CHANNELS 1765 static l2cap_channel_t * l2cap_create_channel_entry(btstack_packet_handler_t packet_handler, l2cap_channel_type_t channel_type, bd_addr_t address, bd_addr_type_t address_type, 1766 uint16_t psm, uint16_t local_mtu, gap_security_level_t security_level){ 1767 1768 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 1769 if (!channel) { 1770 return NULL; 1771 } 1772 1773 // Init memory (make valgrind happy) 1774 memset(channel, 0, sizeof(l2cap_channel_t)); 1775 1776 // fill in 1777 channel->packet_handler = packet_handler; 1778 channel->channel_type = channel_type; 1779 bd_addr_copy(channel->address, address); 1780 channel->address_type = address_type; 1781 channel->psm = psm; 1782 channel->local_mtu = local_mtu; 1783 channel->remote_mtu = L2CAP_DEFAULT_MTU; 1784 channel->required_security_level = security_level; 1785 1786 // 1787 channel->local_cid = l2cap_next_local_cid(); 1788 channel->con_handle = 0; 1789 1790 // set initial state 1791 channel->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 1792 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 1793 channel->remote_sig_id = L2CAP_SIG_ID_INVALID; 1794 channel->local_sig_id = L2CAP_SIG_ID_INVALID; 1795 1796 return channel; 1797 } 1798 #endif 1799 1800 #ifdef ENABLE_CLASSIC 1801 1802 /** 1803 * @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary. 1804 * @param packet_handler 1805 * @param address 1806 * @param psm 1807 * @param mtu 1808 * @param local_cid 1809 */ 1810 1811 uint8_t l2cap_create_channel(btstack_packet_handler_t channel_packet_handler, bd_addr_t address, uint16_t psm, uint16_t mtu, uint16_t * out_local_cid){ 1812 // limit MTU to the size of our outtgoing HCI buffer 1813 uint16_t local_mtu = btstack_min(mtu, l2cap_max_mtu()); 1814 1815 log_info("L2CAP_CREATE_CHANNEL addr %s psm 0x%x mtu %u -> local mtu %u", bd_addr_to_str(address), psm, mtu, local_mtu); 1816 1817 l2cap_channel_t * channel = l2cap_create_channel_entry(channel_packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, address, BD_ADDR_TYPE_CLASSIC, psm, local_mtu, LEVEL_0); 1818 if (!channel) { 1819 return BTSTACK_MEMORY_ALLOC_FAILED; 1820 } 1821 1822 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1823 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 1824 #endif 1825 1826 // add to connections list 1827 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel); 1828 1829 // store local_cid 1830 if (out_local_cid){ 1831 *out_local_cid = channel->local_cid; 1832 } 1833 1834 // check if hci connection is already usable 1835 hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_CLASSIC); 1836 if (conn){ 1837 log_info("l2cap_create_channel, hci connection already exists"); 1838 l2cap_handle_connection_complete(conn->con_handle, channel); 1839 // check if remote supported fearures are already received 1840 if (conn->bonding_flags & BONDING_RECEIVED_REMOTE_FEATURES) { 1841 l2cap_handle_remote_supported_features_received(channel); 1842 } 1843 } 1844 1845 l2cap_run(); 1846 1847 return 0; 1848 } 1849 1850 void 1851 l2cap_disconnect(uint16_t local_cid, uint8_t reason){ 1852 log_info("L2CAP_DISCONNECT local_cid 0x%x reason 0x%x", local_cid, reason); 1853 // find channel for local_cid 1854 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1855 if (channel) { 1856 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 1857 } 1858 // process 1859 l2cap_run(); 1860 } 1861 1862 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 1863 // mark all channels before emitting open events as these could trigger new connetion requests to the same device 1864 btstack_linked_list_iterator_t it; 1865 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1866 while (btstack_linked_list_iterator_has_next(&it)){ 1867 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1868 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 1869 if (bd_addr_cmp( channel->address, address) != 0) continue; 1870 // channel for this address found 1871 switch (channel->state){ 1872 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 1873 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 1874 channel->state = L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD; 1875 break; 1876 default: 1877 break; 1878 } 1879 } 1880 // emit and free marked entries. restart loop to deal with list changes 1881 int done = 0; 1882 while (!done) { 1883 done = 1; 1884 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1885 while (btstack_linked_list_iterator_has_next(&it)){ 1886 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1887 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 1888 if (channel->state == L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD){ 1889 done = 0; 1890 // failure, forward error code 1891 l2cap_emit_channel_opened(channel, status); 1892 // discard channel 1893 l2cap_stop_rtx(channel); 1894 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1895 btstack_memory_l2cap_channel_free(channel); 1896 break; 1897 } 1898 } 1899 } 1900 1901 } 1902 1903 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 1904 btstack_linked_list_iterator_t it; 1905 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1906 while (btstack_linked_list_iterator_has_next(&it)){ 1907 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1908 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 1909 if ( ! bd_addr_cmp( channel->address, address) ){ 1910 l2cap_handle_connection_complete(handle, channel); 1911 } 1912 } 1913 // process 1914 l2cap_run(); 1915 } 1916 #endif 1917 1918 static void l2cap_notify_channel_can_send(void){ 1919 int done = 0; 1920 while (!done){ 1921 done = 1; 1922 btstack_linked_list_iterator_t it; 1923 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1924 while (btstack_linked_list_iterator_has_next(&it)){ 1925 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1926 if (!channel->waiting_for_can_send_now) continue; 1927 int can_send = 0; 1928 if (l2cap_is_le_channel_type(channel->channel_type)){ 1929 #ifdef ENABLE_BLE 1930 can_send = hci_can_send_acl_le_packet_now(); 1931 #endif 1932 } else { 1933 #ifdef ENABLE_CLASSIC 1934 can_send = hci_can_send_acl_classic_packet_now(); 1935 #endif 1936 } 1937 if (!can_send) continue; 1938 // requeue for fairness 1939 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1940 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 1941 // emit can send 1942 channel->waiting_for_can_send_now = 0; 1943 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 1944 // exit inner loop as we just broke the iterator, but try again 1945 done = 0; 1946 break; 1947 } 1948 } 1949 } 1950 1951 #ifdef L2CAP_USES_CHANNELS 1952 1953 static int l2cap_send_open_failed_on_hci_disconnect(l2cap_channel_t * channel){ 1954 // open cannot fail for for incoming connections 1955 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) return 0; 1956 1957 // check state 1958 switch (channel->state){ 1959 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 1960 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 1961 case L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES: 1962 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 1963 case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT: 1964 case L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES: 1965 case L2CAP_STATE_WAIT_CONNECT_RSP: 1966 case L2CAP_STATE_CONFIG: 1967 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 1968 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST: 1969 case L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE: 1970 case L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD: 1971 return 1; 1972 1973 case L2CAP_STATE_OPEN: 1974 case L2CAP_STATE_CLOSED: 1975 case L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES: 1976 case L2CAP_STATE_WAIT_DISCONNECT: 1977 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_INSUFFICIENT_SECURITY: 1978 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 1979 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 1980 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 1981 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 1982 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE: 1983 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT: 1984 case L2CAP_STATE_INVALID: 1985 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 1986 return 0; 1987 // no default here, to get a warning about new states 1988 } 1989 // still, the compiler insists on a return value 1990 return 0; 1991 } 1992 #endif 1993 1994 #ifdef ENABLE_CLASSIC 1995 static void l2cap_handle_hci_disconnect_event(l2cap_channel_t * channel){ 1996 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 1997 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 1998 } else { 1999 l2cap_emit_channel_closed(channel); 2000 } 2001 btstack_memory_l2cap_channel_free(channel); 2002 } 2003 #endif 2004 2005 #ifdef ENABLE_LE_DATA_CHANNELS 2006 static void l2cap_handle_hci_le_disconnect_event(l2cap_channel_t * channel){ 2007 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 2008 l2cap_emit_le_channel_opened(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 2009 } else { 2010 l2cap_emit_le_channel_closed(channel); 2011 } 2012 btstack_memory_l2cap_channel_free(channel); 2013 } 2014 #endif 2015 2016 static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t cid, uint8_t *packet, uint16_t size){ 2017 2018 UNUSED(packet_type); // ok: registered with hci_event_callback_registration 2019 UNUSED(cid); // ok: there is no channel 2020 UNUSED(size); // ok: fixed format events read from HCI buffer 2021 2022 #ifdef ENABLE_CLASSIC 2023 bd_addr_t address; 2024 int hci_con_used; 2025 #endif 2026 #ifdef L2CAP_USES_CHANNELS 2027 hci_con_handle_t handle; 2028 btstack_linked_list_iterator_t it; 2029 #endif 2030 2031 switch(hci_event_packet_get_type(packet)){ 2032 2033 // Notify channel packet handler if they can send now 2034 case HCI_EVENT_TRANSPORT_PACKET_SENT: 2035 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 2036 l2cap_run(); // try sending signaling packets first 2037 l2cap_notify_channel_can_send(); 2038 break; 2039 2040 case HCI_EVENT_COMMAND_STATUS: 2041 l2cap_run(); // try sending signaling packets first 2042 break; 2043 2044 #ifdef ENABLE_CLASSIC 2045 // handle connection complete events 2046 case HCI_EVENT_CONNECTION_COMPLETE: 2047 reverse_bd_addr(&packet[5], address); 2048 if (packet[2] == 0){ 2049 handle = little_endian_read_16(packet, 3); 2050 l2cap_handle_connection_success_for_addr(address, handle); 2051 } else { 2052 l2cap_handle_connection_failed_for_addr(address, packet[2]); 2053 } 2054 break; 2055 2056 // handle successful create connection cancel command 2057 case HCI_EVENT_COMMAND_COMPLETE: 2058 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_create_connection_cancel)) { 2059 if (packet[5] == 0){ 2060 reverse_bd_addr(&packet[6], address); 2061 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 2062 l2cap_handle_connection_failed_for_addr(address, 0x16); 2063 } 2064 } 2065 l2cap_run(); // try sending signaling packets first 2066 break; 2067 #endif 2068 2069 #ifdef L2CAP_USES_CHANNELS 2070 // handle disconnection complete events 2071 case HCI_EVENT_DISCONNECTION_COMPLETE: 2072 handle = little_endian_read_16(packet, 3); 2073 // send l2cap open failed or closed events for all channels on this handle and free them 2074 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2075 while (btstack_linked_list_iterator_has_next(&it)){ 2076 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2077 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2078 if (channel->con_handle != handle) continue; 2079 btstack_linked_list_iterator_remove(&it); 2080 switch(channel->channel_type){ 2081 #ifdef ENABLE_CLASSIC 2082 case L2CAP_CHANNEL_TYPE_CLASSIC: 2083 l2cap_stop_rtx(channel); 2084 l2cap_handle_hci_disconnect_event(channel); 2085 break; 2086 #endif 2087 #ifdef ENABLE_LE_DATA_CHANNELS 2088 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2089 l2cap_handle_hci_le_disconnect_event(channel); 2090 break; 2091 #endif 2092 default: 2093 break; 2094 } 2095 } 2096 #endif 2097 2098 // HCI Connection Timeouts 2099 #ifdef ENABLE_CLASSIC 2100 case L2CAP_EVENT_TIMEOUT_CHECK: 2101 handle = little_endian_read_16(packet, 2); 2102 if (gap_get_connection_type(handle) != GAP_CONNECTION_ACL) break; 2103 if (hci_authentication_active_for_handle(handle)) break; 2104 hci_con_used = 0; 2105 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2106 while (btstack_linked_list_iterator_has_next(&it)){ 2107 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2108 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2109 if (channel->con_handle != handle) continue; 2110 hci_con_used = 1; 2111 break; 2112 } 2113 if (hci_con_used) break; 2114 if (!hci_can_send_command_packet_now()) break; 2115 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 2116 break; 2117 2118 case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE: 2119 handle = little_endian_read_16(packet, 3); 2120 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2121 while (btstack_linked_list_iterator_has_next(&it)){ 2122 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2123 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2124 if (channel->con_handle != handle) continue; 2125 l2cap_handle_remote_supported_features_received(channel); 2126 break; 2127 } 2128 break; 2129 2130 case GAP_EVENT_SECURITY_LEVEL: 2131 handle = little_endian_read_16(packet, 2); 2132 log_info("l2cap - security level update"); 2133 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2134 while (btstack_linked_list_iterator_has_next(&it)){ 2135 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2136 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2137 if (channel->con_handle != handle) continue; 2138 2139 gap_security_level_t actual_level = (gap_security_level_t) packet[4]; 2140 gap_security_level_t required_level = channel->required_security_level; 2141 2142 log_info("channel state %u: actual %u >= required %u?", channel->state, actual_level, required_level); 2143 2144 switch (channel->state){ 2145 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 2146 if (actual_level >= required_level){ 2147 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2148 // we need to know if ERTM is supported before sending a config response 2149 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 2150 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 2151 channel->state = L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES; 2152 #else 2153 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 2154 l2cap_emit_incoming_connection(channel); 2155 #endif 2156 } else { 2157 channel->reason = 0x0003; // security block 2158 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2159 } 2160 break; 2161 2162 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 2163 if (actual_level >= required_level){ 2164 l2cap_ready_to_connect(channel); 2165 } else { 2166 // disconnnect, authentication not good enough 2167 hci_disconnect_security_block(handle); 2168 } 2169 break; 2170 2171 default: 2172 break; 2173 } 2174 } 2175 break; 2176 #endif 2177 2178 default: 2179 break; 2180 } 2181 2182 l2cap_run(); 2183 } 2184 2185 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t cid, uint16_t data){ 2186 // Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused." 2187 if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 2188 signaling_responses[signaling_responses_pending].handle = handle; 2189 signaling_responses[signaling_responses_pending].code = code; 2190 signaling_responses[signaling_responses_pending].sig_id = sig_id; 2191 signaling_responses[signaling_responses_pending].cid = cid; 2192 signaling_responses[signaling_responses_pending].data = data; 2193 signaling_responses_pending++; 2194 l2cap_run(); 2195 } 2196 } 2197 2198 #ifdef ENABLE_CLASSIC 2199 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 2200 channel->remote_sig_id = identifier; 2201 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 2202 l2cap_run(); 2203 } 2204 2205 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 2206 2207 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid); 2208 l2cap_service_t *service = l2cap_get_service(psm); 2209 if (!service) { 2210 // 0x0002 PSM not supported 2211 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 2212 return; 2213 } 2214 2215 hci_connection_t * hci_connection = hci_connection_for_handle( handle ); 2216 if (!hci_connection) { 2217 // 2218 log_error("no hci_connection for handle %u", handle); 2219 return; 2220 } 2221 2222 // alloc structure 2223 // log_info("l2cap_handle_connection_request register channel"); 2224 l2cap_channel_t * channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, hci_connection->address, BD_ADDR_TYPE_CLASSIC, 2225 psm, service->mtu, service->required_security_level); 2226 if (!channel){ 2227 // 0x0004 No resources available 2228 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 2229 return; 2230 } 2231 2232 channel->con_handle = handle; 2233 channel->remote_cid = source_cid; 2234 channel->remote_sig_id = sig_id; 2235 2236 // limit local mtu to max acl packet length - l2cap header 2237 if (channel->local_mtu > l2cap_max_mtu()) { 2238 channel->local_mtu = l2cap_max_mtu(); 2239 } 2240 2241 // set initial state 2242 channel->state = L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE; 2243 channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND | L2CAP_CHANNEL_STATE_VAR_INCOMING); 2244 2245 // add to connections list 2246 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel); 2247 2248 // assert security requirements 2249 gap_request_security_level(handle, channel->required_security_level); 2250 } 2251 2252 void l2cap_accept_connection(uint16_t local_cid){ 2253 log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid); 2254 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 2255 if (!channel) { 2256 log_error("l2cap_accept_connection called but local_cid 0x%x not found", local_cid); 2257 return; 2258 } 2259 2260 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2261 // configure L2CAP Basic mode 2262 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2263 #endif 2264 2265 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 2266 2267 // process 2268 l2cap_run(); 2269 } 2270 2271 void l2cap_decline_connection(uint16_t local_cid){ 2272 log_info("L2CAP_DECLINE_CONNECTION local_cid 0x%x", local_cid); 2273 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 2274 if (!channel) { 2275 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 2276 return; 2277 } 2278 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2279 channel->reason = 0x04; // no resources available 2280 l2cap_run(); 2281 } 2282 2283 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2284 static void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 2285 2286 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2287 uint8_t use_fcs = 1; 2288 #endif 2289 2290 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2291 2292 uint16_t flags = little_endian_read_16(command, 6); 2293 if (flags & 1) { 2294 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT); 2295 } 2296 2297 // accept the other's configuration options 2298 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2299 uint16_t pos = 8; 2300 while (pos < end_pos){ 2301 uint8_t option_hint = command[pos] >> 7; 2302 uint8_t option_type = command[pos] & 0x7f; 2303 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2304 pos++; 2305 uint8_t length = command[pos++]; 2306 // MTU { type(8): 1, len(8):2, MTU(16) } 2307 if (option_type == L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT && length == 2){ 2308 channel->remote_mtu = little_endian_read_16(command, pos); 2309 log_info("Remote MTU %u", channel->remote_mtu); 2310 if (channel->remote_mtu > l2cap_max_mtu()){ 2311 log_info("Remote MTU %u larger than outgoing buffer, only using MTU = %u", channel->remote_mtu, l2cap_max_mtu()); 2312 channel->remote_mtu = l2cap_max_mtu(); 2313 } 2314 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 2315 } 2316 // Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)} 2317 if (option_type == L2CAP_CONFIG_OPTION_TYPE_FLUSH_TIMEOUT && length == 2){ 2318 channel->flush_timeout = little_endian_read_16(command, pos); 2319 log_info("Flush timeout: %u ms", channel->flush_timeout); 2320 } 2321 2322 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2323 // Retransmission and Flow Control Option 2324 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2325 l2cap_channel_mode_t mode = (l2cap_channel_mode_t) command[pos]; 2326 switch(channel->mode){ 2327 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2328 // Store remote config 2329 channel->remote_tx_window_size = command[pos+1]; 2330 channel->remote_max_transmit = command[pos+2]; 2331 channel->remote_retransmission_timeout_ms = little_endian_read_16(command, pos + 3); 2332 channel->remote_monitor_timeout_ms = little_endian_read_16(command, pos + 5); 2333 channel->remote_mps = little_endian_read_16(command, pos + 7); 2334 log_info("FC&C config: tx window: %u, max transmit %u, retrans timeout %u, monitor timeout %u, mps %u", 2335 channel->remote_tx_window_size, 2336 channel->remote_max_transmit, 2337 channel->remote_retransmission_timeout_ms, 2338 channel->remote_monitor_timeout_ms, 2339 channel->remote_mps); 2340 // If ERTM mandatory, but remote doens't offer ERTM -> disconnect 2341 if (channel->ertm_mandatory && mode != L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 2342 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2343 } else { 2344 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 2345 } 2346 break; 2347 case L2CAP_CHANNEL_MODE_BASIC: 2348 switch (mode){ 2349 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2350 // remote asks for ERTM, but we want basic mode. disconnect if this happens a second time 2351 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED){ 2352 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2353 } 2354 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED); 2355 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED); 2356 break; 2357 default: // case L2CAP_CHANNEL_MODE_BASIC: 2358 // TODO store and evaluate configuration 2359 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 2360 break; 2361 } 2362 break; 2363 default: 2364 break; 2365 } 2366 } 2367 if (option_type == L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE && length == 1){ 2368 use_fcs = command[pos]; 2369 } 2370 #endif 2371 // check for unknown options 2372 if (option_hint == 0 && (option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT || option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE)){ 2373 log_info("l2cap cid %u, unknown options", channel->local_cid); 2374 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2375 } 2376 pos += length; 2377 } 2378 2379 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2380 // "FCS" has precedence over "No FCS" 2381 uint8_t update = channel->fcs_option || use_fcs; 2382 log_info("local fcs: %u, remote fcs: %u -> %u", channel->fcs_option, use_fcs, update); 2383 channel->fcs_option = update; 2384 #endif 2385 } 2386 2387 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2388 static void l2cap_signaling_handle_configure_response(l2cap_channel_t *channel, uint8_t result, uint8_t *command){ 2389 log_info("l2cap_signaling_handle_configure_response"); 2390 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2391 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2392 uint16_t pos = 10; 2393 while (pos < end_pos){ 2394 uint8_t option_hint = command[pos] >> 7; 2395 uint8_t option_type = command[pos] & 0x7f; 2396 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2397 pos++; 2398 uint8_t length = command[pos++]; 2399 2400 // Retransmission and Flow Control Option 2401 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2402 switch (channel->mode){ 2403 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2404 if (channel->ertm_mandatory){ 2405 // ?? 2406 } else { 2407 // On 'Reject - Unacceptable Parameters' to our optional ERTM request, fall back to BASIC mode 2408 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2409 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2410 } 2411 } 2412 break; 2413 case L2CAP_CHANNEL_MODE_BASIC: 2414 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2415 // On 'Reject - Unacceptable Parameters' to our Basic mode request, disconnect 2416 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2417 } 2418 break; 2419 default: 2420 break; 2421 } 2422 } 2423 2424 // check for unknown options 2425 if (option_hint == 0 && (option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT || option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE)){ 2426 log_info("l2cap cid %u, unknown options", channel->local_cid); 2427 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2428 } 2429 2430 pos += length; 2431 } 2432 #else 2433 UNUSED(channel); // ok: no code 2434 UNUSED(result); // ok: no code 2435 UNUSED(command); // ok: no code 2436 #endif 2437 } 2438 2439 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 2440 // log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var); 2441 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 2442 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 2443 // addition check that fixes re-entrance issue causing l2cap event channel opened twice 2444 if (channel->state == L2CAP_STATE_OPEN) return 0; 2445 return 1; 2446 } 2447 2448 2449 // @pre command len is valid, see check in l2cap_signaling_handler_dispatch 2450 static void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 2451 2452 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 2453 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2454 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2455 uint16_t result = 0; 2456 2457 log_info("L2CAP signaling handler code %u, state %u", code, channel->state); 2458 2459 // handle DISCONNECT REQUESTS seperately 2460 if (code == DISCONNECTION_REQUEST){ 2461 switch (channel->state){ 2462 case L2CAP_STATE_CONFIG: 2463 case L2CAP_STATE_OPEN: 2464 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 2465 case L2CAP_STATE_WAIT_DISCONNECT: 2466 l2cap_handle_disconnect_request(channel, identifier); 2467 break; 2468 2469 default: 2470 // ignore in other states 2471 break; 2472 } 2473 return; 2474 } 2475 2476 // @STATEMACHINE(l2cap) 2477 switch (channel->state) { 2478 2479 case L2CAP_STATE_WAIT_CONNECT_RSP: 2480 switch (code){ 2481 case CONNECTION_RESPONSE: 2482 if (cmd_len < 8){ 2483 // command imcomplete 2484 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2485 break; 2486 } 2487 l2cap_stop_rtx(channel); 2488 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2489 switch (result) { 2490 case 0: 2491 // successful connection 2492 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2493 channel->state = L2CAP_STATE_CONFIG; 2494 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 2495 break; 2496 case 1: 2497 // connection pending. get some coffee, but start the ERTX 2498 l2cap_start_ertx(channel); 2499 break; 2500 default: 2501 // channel closed 2502 channel->state = L2CAP_STATE_CLOSED; 2503 // map l2cap connection response result to BTstack status enumeration 2504 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 2505 2506 // drop link key if security block 2507 if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 2508 gap_drop_link_key_for_bd_addr(channel->address); 2509 } 2510 2511 // discard channel 2512 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2513 btstack_memory_l2cap_channel_free(channel); 2514 break; 2515 } 2516 break; 2517 2518 default: 2519 //@TODO: implement other signaling packets 2520 break; 2521 } 2522 break; 2523 2524 case L2CAP_STATE_CONFIG: 2525 switch (code) { 2526 case CONFIGURE_REQUEST: 2527 if (cmd_len < 4){ 2528 // command incomplete 2529 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2530 break; 2531 } 2532 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 2533 l2cap_signaling_handle_configure_request(channel, command); 2534 if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){ 2535 // only done if continuation not set 2536 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ); 2537 } 2538 break; 2539 case CONFIGURE_RESPONSE: 2540 if (cmd_len < 6){ 2541 // command incomplete 2542 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2543 break; 2544 } 2545 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2546 l2cap_stop_rtx(channel); 2547 l2cap_signaling_handle_configure_response(channel, result, command); 2548 switch (result){ 2549 case 0: // success 2550 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP); 2551 break; 2552 case 4: // pending 2553 l2cap_start_ertx(channel); 2554 break; 2555 default: 2556 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2557 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION && channel->ertm_mandatory){ 2558 // remote does not offer ertm but it's required 2559 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2560 break; 2561 } 2562 #endif 2563 // retry on negative result 2564 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 2565 break; 2566 } 2567 break; 2568 default: 2569 break; 2570 } 2571 if (l2cap_channel_ready_for_open(channel)){ 2572 // for open: 2573 channel->state = L2CAP_STATE_OPEN; 2574 l2cap_emit_channel_opened(channel, 0); 2575 } 2576 break; 2577 2578 case L2CAP_STATE_WAIT_DISCONNECT: 2579 switch (code) { 2580 case DISCONNECTION_RESPONSE: 2581 l2cap_finialize_channel_close(channel); 2582 break; 2583 default: 2584 //@TODO: implement other signaling packets 2585 break; 2586 } 2587 break; 2588 2589 case L2CAP_STATE_CLOSED: 2590 // @TODO handle incoming requests 2591 break; 2592 2593 case L2CAP_STATE_OPEN: 2594 //@TODO: implement other signaling packets, e.g. re-configure 2595 break; 2596 default: 2597 break; 2598 } 2599 // log_info("new state %u", channel->state); 2600 } 2601 2602 2603 // @pre command len is valid, see check in l2cap_acl_classic_handler 2604 static void l2cap_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command){ 2605 2606 btstack_linked_list_iterator_t it; 2607 2608 // get code, signalind identifier and command len 2609 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 2610 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2611 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2612 2613 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_RESPONSE 2614 if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_RESPONSE){ 2615 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 2616 return; 2617 } 2618 2619 // general commands without an assigned channel 2620 switch(code) { 2621 2622 case CONNECTION_REQUEST: 2623 if (cmd_len == 4){ 2624 uint16_t psm = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2625 uint16_t source_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 2626 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 2627 } else { 2628 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 2629 } 2630 return; 2631 2632 case ECHO_REQUEST: 2633 l2cap_register_signaling_response(handle, code, sig_id, 0, 0); 2634 return; 2635 2636 case INFORMATION_REQUEST: 2637 if (cmd_len == 2) { 2638 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2639 l2cap_register_signaling_response(handle, code, sig_id, 0, info_type); 2640 } else { 2641 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 2642 } 2643 return; 2644 2645 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2646 case INFORMATION_RESPONSE: { 2647 hci_connection_t * connection = hci_connection_for_handle(handle); 2648 if (!connection) return; 2649 if (cmd_len >= 4) { 2650 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2651 uint16_t result = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 2652 if (result != 0) return; 2653 if (info_type != L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED) return; 2654 if (cmd_len >= 6) { 2655 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_DONE; 2656 connection->l2cap_state.extended_feature_mask = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2657 log_info("extended features mask 0x%02x", connection->l2cap_state.extended_feature_mask); 2658 // trigger connection request 2659 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2660 while (btstack_linked_list_iterator_has_next(&it)){ 2661 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2662 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2663 if (channel->con_handle != handle) continue; 2664 // bail if ERTM was requested but is not supported 2665 if ((channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) && ((connection->l2cap_state.extended_feature_mask & 0x08) == 0)){ 2666 if (channel->ertm_mandatory){ 2667 // channel closed 2668 channel->state = L2CAP_STATE_CLOSED; 2669 // map l2cap connection response result to BTstack status enumeration 2670 l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_ERTM_NOT_SUPPORTED); 2671 // discard channel 2672 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2673 btstack_memory_l2cap_channel_free(channel); 2674 continue; 2675 } else { 2676 // fallback to Basic mode 2677 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2678 } 2679 } 2680 // start connecting 2681 if (channel->state == L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES){ 2682 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 2683 } 2684 // respond to connection request 2685 if (channel->state == L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES){ 2686 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 2687 l2cap_emit_incoming_connection(channel); 2688 } 2689 } 2690 return; // cmd len valid 2691 } 2692 } 2693 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 2694 return; 2695 } 2696 #endif 2697 2698 default: 2699 break; 2700 } 2701 2702 // Get potential destination CID 2703 uint16_t dest_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2704 2705 // Find channel for this sig_id and connection handle 2706 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2707 while (btstack_linked_list_iterator_has_next(&it)){ 2708 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2709 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2710 if (channel->con_handle != handle) continue; 2711 if (code & 1) { 2712 // match odd commands (responses) by previous signaling identifier 2713 if (channel->local_sig_id == sig_id) { 2714 l2cap_signaling_handler_channel(channel, command); 2715 break; 2716 } 2717 } else { 2718 // match even commands (requests) by local channel id 2719 if (channel->local_cid == dest_cid) { 2720 l2cap_signaling_handler_channel(channel, command); 2721 break; 2722 } 2723 } 2724 } 2725 } 2726 #endif 2727 2728 #ifdef ENABLE_BLE 2729 2730 static void l2cap_emit_connection_parameter_update_response(hci_con_handle_t con_handle, uint16_t result){ 2731 uint8_t event[6]; 2732 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE; 2733 event[1] = 4; 2734 little_endian_store_16(event, 2, con_handle); 2735 little_endian_store_16(event, 4, result); 2736 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 2737 if (!l2cap_event_packet_handler) return; 2738 (*l2cap_event_packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event)); 2739 } 2740 2741 // @returns valid 2742 static int l2cap_le_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command, uint8_t sig_id){ 2743 hci_connection_t * connection; 2744 uint16_t result; 2745 uint8_t event[10]; 2746 2747 #ifdef ENABLE_LE_DATA_CHANNELS 2748 btstack_linked_list_iterator_t it; 2749 l2cap_channel_t * channel; 2750 uint16_t local_cid; 2751 uint16_t le_psm; 2752 uint16_t new_credits; 2753 uint16_t credits_before; 2754 l2cap_service_t * service; 2755 uint16_t source_cid; 2756 #endif 2757 2758 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 2759 uint16_t len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2760 log_info("l2cap_le_signaling_handler_dispatch: command 0x%02x, sig id %u, len %u", code, sig_id, len); 2761 2762 switch (code){ 2763 2764 case CONNECTION_PARAMETER_UPDATE_REQUEST: 2765 // check size 2766 if (len < 8) return 0; 2767 connection = hci_connection_for_handle(handle); 2768 if (connection){ 2769 if (connection->role != HCI_ROLE_MASTER){ 2770 // reject command without notifying upper layer when not in master role 2771 return 0; 2772 } 2773 le_connection_parameter_range_t existing_range; 2774 gap_get_connection_parameter_range(&existing_range); 2775 uint16_t le_conn_interval_min = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2776 uint16_t le_conn_interval_max = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 2777 uint16_t le_conn_latency = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2778 uint16_t le_supervision_timeout = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+6); 2779 2780 int update_parameter = gap_connection_parameter_range_included(&existing_range, le_conn_interval_min, le_conn_interval_max, le_conn_latency, le_supervision_timeout); 2781 if (update_parameter){ 2782 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE; 2783 connection->le_conn_interval_min = le_conn_interval_min; 2784 connection->le_conn_interval_max = le_conn_interval_max; 2785 connection->le_conn_latency = le_conn_latency; 2786 connection->le_supervision_timeout = le_supervision_timeout; 2787 } else { 2788 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY; 2789 } 2790 connection->le_con_param_update_identifier = sig_id; 2791 } 2792 2793 if (!l2cap_event_packet_handler) break; 2794 2795 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST; 2796 event[1] = 8; 2797 memcpy(&event[2], &command[4], 8); 2798 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 2799 (*l2cap_event_packet_handler)( HCI_EVENT_PACKET, 0, event, sizeof(event)); 2800 break; 2801 2802 case CONNECTION_PARAMETER_UPDATE_RESPONSE: 2803 // check size 2804 if (len < 2) return 0; 2805 result = little_endian_read_16(command, 4); 2806 l2cap_emit_connection_parameter_update_response(handle, result); 2807 break; 2808 2809 #ifdef ENABLE_LE_DATA_CHANNELS 2810 2811 case COMMAND_REJECT: 2812 // Find channel for this sig_id and connection handle 2813 channel = NULL; 2814 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2815 while (btstack_linked_list_iterator_has_next(&it)){ 2816 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2817 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 2818 if (a_channel->con_handle != handle) continue; 2819 if (a_channel->local_sig_id != sig_id) continue; 2820 channel = a_channel; 2821 break; 2822 } 2823 if (!channel) break; 2824 2825 // if received while waiting for le connection response, assume legacy device 2826 if (channel->state == L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE){ 2827 channel->state = L2CAP_STATE_CLOSED; 2828 // no official value for this, use: Connection refused – LE_PSM not supported - 0x0002 2829 l2cap_emit_le_channel_opened(channel, 0x0002); 2830 2831 // discard channel 2832 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2833 btstack_memory_l2cap_channel_free(channel); 2834 break; 2835 } 2836 break; 2837 2838 case LE_CREDIT_BASED_CONNECTION_REQUEST: 2839 // check size 2840 if (len < 10) return 0; 2841 2842 // get hci connection, bail if not found (must not happen) 2843 connection = hci_connection_for_handle(handle); 2844 if (!connection) return 0; 2845 2846 // check if service registered 2847 le_psm = little_endian_read_16(command, 4); 2848 service = l2cap_le_get_service(le_psm); 2849 source_cid = little_endian_read_16(command, 6); 2850 2851 if (service){ 2852 if (source_cid < 0x40){ 2853 // 0x0009 Connection refused - Invalid Source CID 2854 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0009); 2855 return 1; 2856 } 2857 2858 // go through list of channels for this ACL connection and check if we get a match 2859 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2860 while (btstack_linked_list_iterator_has_next(&it)){ 2861 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2862 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 2863 if (a_channel->con_handle != handle) continue; 2864 if (a_channel->remote_cid != source_cid) continue; 2865 // 0x000a Connection refused - Source CID already allocated 2866 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x000a); 2867 return 1; 2868 } 2869 2870 // security: check encryption 2871 if (service->required_security_level >= LEVEL_2){ 2872 if (gap_encryption_key_size(handle) == 0){ 2873 // 0x0008 Connection refused - insufficient encryption 2874 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0008); 2875 return 1; 2876 } 2877 // anything less than 16 byte key size is insufficient 2878 if (gap_encryption_key_size(handle) < 16){ 2879 // 0x0007 Connection refused – insufficient encryption key size 2880 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0007); 2881 return 1; 2882 } 2883 } 2884 2885 // security: check authencation 2886 if (service->required_security_level >= LEVEL_3){ 2887 if (!gap_authenticated(handle)){ 2888 // 0x0005 Connection refused – insufficient authentication 2889 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0005); 2890 return 1; 2891 } 2892 } 2893 2894 // security: check authorization 2895 if (service->required_security_level >= LEVEL_4){ 2896 if (gap_authorization_state(handle) != AUTHORIZATION_GRANTED){ 2897 // 0x0006 Connection refused – insufficient authorization 2898 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0006); 2899 return 1; 2900 } 2901 } 2902 2903 // allocate channel 2904 channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL, connection->address, 2905 BD_ADDR_TYPE_LE_RANDOM, le_psm, service->mtu, service->required_security_level); 2906 if (!channel){ 2907 // 0x0004 Connection refused – no resources available 2908 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 2909 return 1; 2910 } 2911 2912 channel->con_handle = handle; 2913 channel->remote_cid = source_cid; 2914 channel->remote_sig_id = sig_id; 2915 channel->remote_mtu = little_endian_read_16(command, 8); 2916 channel->remote_mps = little_endian_read_16(command, 10); 2917 channel->credits_outgoing = little_endian_read_16(command, 12); 2918 2919 // set initial state 2920 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 2921 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_INCOMING; 2922 2923 // add to connections list 2924 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel); 2925 2926 // post connection request event 2927 l2cap_emit_le_incoming_connection(channel); 2928 2929 } else { 2930 // Connection refused – LE_PSM not supported 2931 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 2932 } 2933 break; 2934 2935 case LE_CREDIT_BASED_CONNECTION_RESPONSE: 2936 // check size 2937 if (len < 10) return 0; 2938 2939 // Find channel for this sig_id and connection handle 2940 channel = NULL; 2941 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2942 while (btstack_linked_list_iterator_has_next(&it)){ 2943 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2944 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 2945 if (a_channel->con_handle != handle) continue; 2946 if (a_channel->local_sig_id != sig_id) continue; 2947 channel = a_channel; 2948 break; 2949 } 2950 if (!channel) break; 2951 2952 // cid + 0 2953 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+8); 2954 if (result){ 2955 channel->state = L2CAP_STATE_CLOSED; 2956 // map l2cap connection response result to BTstack status enumeration 2957 l2cap_emit_le_channel_opened(channel, result); 2958 2959 // discard channel 2960 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2961 btstack_memory_l2cap_channel_free(channel); 2962 break; 2963 } 2964 2965 // success 2966 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 2967 channel->remote_mtu = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 2968 channel->remote_mps = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 4); 2969 channel->credits_outgoing = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 6); 2970 channel->state = L2CAP_STATE_OPEN; 2971 l2cap_emit_le_channel_opened(channel, result); 2972 break; 2973 2974 case LE_FLOW_CONTROL_CREDIT: 2975 // check size 2976 if (len < 4) return 0; 2977 2978 // find channel 2979 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 2980 channel = l2cap_get_channel_for_local_cid(local_cid); 2981 if (!channel) { 2982 log_error("l2cap: no channel for cid 0x%02x", local_cid); 2983 break; 2984 } 2985 new_credits = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 2986 credits_before = channel->credits_outgoing; 2987 channel->credits_outgoing += new_credits; 2988 // check for credit overrun 2989 if (credits_before > channel->credits_outgoing){ 2990 log_error("l2cap: new credits caused overrrun for cid 0x%02x, disconnecting", local_cid); 2991 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2992 break; 2993 } 2994 log_info("l2cap: %u credits for 0x%02x, now %u", new_credits, local_cid, channel->credits_outgoing); 2995 break; 2996 2997 case DISCONNECTION_REQUEST: 2998 2999 // check size 3000 if (len < 4) return 0; 3001 3002 // find channel 3003 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3004 channel = l2cap_get_channel_for_local_cid(local_cid); 3005 if (!channel) { 3006 log_error("l2cap: no channel for cid 0x%02x", local_cid); 3007 break; 3008 } 3009 channel->remote_sig_id = sig_id; 3010 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 3011 break; 3012 3013 #endif 3014 3015 case DISCONNECTION_RESPONSE: 3016 break; 3017 3018 default: 3019 // command unknown -> reject command 3020 return 0; 3021 } 3022 return 1; 3023 } 3024 #endif 3025 3026 static void l2cap_acl_classic_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3027 #ifdef ENABLE_CLASSIC 3028 l2cap_channel_t * l2cap_channel; 3029 l2cap_fixed_channel_t * l2cap_fixed_channel; 3030 3031 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3032 switch (channel_id) { 3033 3034 case L2CAP_CID_SIGNALING: { 3035 uint16_t command_offset = 8; 3036 while (command_offset < size) { 3037 // assert signaling command is fully inside packet 3038 uint16_t data_len = little_endian_read_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3039 uint32_t next_command_offset = ((uint32_t) command_offset) + L2CAP_SIGNALING_COMMAND_DATA_OFFSET + data_len; 3040 if (next_command_offset > size){ 3041 log_error("l2cap signaling command len invalid -> drop"); 3042 break; 3043 } 3044 // handle signaling command 3045 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 3046 // go to next command 3047 command_offset = (uint16_t) next_command_offset; 3048 } 3049 break; 3050 } 3051 case L2CAP_CID_CONNECTIONLESS_CHANNEL: 3052 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_CONNECTIONLESS_CHANNEL); 3053 if (!l2cap_fixed_channel) break; 3054 if (!l2cap_fixed_channel->packet_handler) break; 3055 (*l2cap_fixed_channel->packet_handler)(UCD_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3056 break; 3057 3058 default: 3059 // Find channel for this channel_id and connection handle 3060 l2cap_channel = l2cap_get_channel_for_local_cid(channel_id); 3061 if (l2cap_channel) { 3062 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3063 if (l2cap_channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 3064 3065 int fcs_size = l2cap_channel->fcs_option ? 2 : 0; 3066 3067 // assert control + FCS fields are inside 3068 if (size < COMPLETE_L2CAP_HEADER+2+fcs_size) break; 3069 3070 if (l2cap_channel->fcs_option){ 3071 // verify FCS (required if one side requested it) 3072 uint16_t fcs_calculated = crc16_calc(&packet[4], size - (4+2)); 3073 uint16_t fcs_packet = little_endian_read_16(packet, size-2); 3074 if (fcs_calculated == fcs_packet){ 3075 log_info("Packet FCS 0x%04x verified", fcs_packet); 3076 } else { 3077 log_error("FCS mismatch! Packet 0x%04x, calculated 0x%04x", fcs_packet, fcs_calculated); 3078 // TODO: trigger retransmission or something like that 3079 break; 3080 } 3081 } 3082 3083 // switch on packet type 3084 uint16_t control = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3085 uint8_t req_seq = (control >> 8) & 0x3f; 3086 int final = (control >> 7) & 0x01; 3087 if (control & 1){ 3088 // S-Frame 3089 int poll = (control >> 4) & 0x01; 3090 l2cap_supervisory_function_t s = (l2cap_supervisory_function_t) ((control >> 2) & 0x03); 3091 log_info("Control: 0x%04x => Supervisory function %u, ReqSeq %02u", control, (int) s, req_seq); 3092 l2cap_ertm_tx_packet_state_t * tx_state; 3093 switch (s){ 3094 case L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY: 3095 log_info("L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY"); 3096 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3097 if (poll && final){ 3098 // S-frames shall not be transmitted with both the F-bit and the P-bit set to 1 at the same time. 3099 log_error("P=F=1 in S-Frame"); 3100 break; 3101 } 3102 if (poll){ 3103 // check if we did request selective retransmission before <==> we have stored SDU segments 3104 int i; 3105 int num_stored_out_of_order_packets = 0; 3106 for (i=0;i<l2cap_channel->num_rx_buffers;i++){ 3107 int index = l2cap_channel->rx_store_index + i; 3108 if (index >= l2cap_channel->num_rx_buffers){ 3109 index -= l2cap_channel->num_rx_buffers; 3110 } 3111 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3112 if (!rx_state->valid) continue; 3113 num_stored_out_of_order_packets++; 3114 } 3115 if (num_stored_out_of_order_packets){ 3116 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3117 } else { 3118 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3119 } 3120 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = 1; 3121 } 3122 if (final){ 3123 // Stop-MonitorTimer 3124 l2cap_ertm_stop_monitor_timer(l2cap_channel); 3125 // If UnackedFrames > 0 then Start-RetransTimer 3126 if (l2cap_channel->unacked_frames){ 3127 l2cap_ertm_start_retransmission_timer(l2cap_channel); 3128 } 3129 3130 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3131 l2cap_channel->tx_send_index = l2cap_channel->tx_read_index; 3132 } 3133 break; 3134 case L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT: 3135 log_info("L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT"); 3136 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3137 // rsetart transmittion from last unacknowledted packet (earlier packets already freed in l2cap_ertm_process_req_seq) 3138 l2cap_channel->tx_send_index = l2cap_channel->tx_read_index; 3139 break; 3140 case L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY: 3141 log_error("L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY"); 3142 break; 3143 case L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT: 3144 log_info("L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT"); 3145 if (poll){ 3146 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3147 } 3148 // find requested i-frame 3149 tx_state = l2cap_ertm_get_tx_state(l2cap_channel, req_seq); 3150 if (tx_state){ 3151 log_info("Retransmission for tx_seq %u requested", req_seq); 3152 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = poll; 3153 tx_state->retransmission_requested = 1; 3154 l2cap_channel->srej_active = 1; 3155 } 3156 break; 3157 default: 3158 break; 3159 } 3160 break; 3161 } else { 3162 // I-Frame 3163 // get control 3164 l2cap_segmentation_and_reassembly_t sar = (l2cap_segmentation_and_reassembly_t) (control >> 14); 3165 uint8_t tx_seq = (control >> 1) & 0x3f; 3166 log_info("Control: 0x%04x => SAR %u, ReqSeq %02u, R?, TxSeq %02u", control, (int) sar, req_seq, tx_seq); 3167 log_info("SAR: pos %u", l2cap_channel->reassembly_pos); 3168 log_info("State: expected_tx_seq %02u, req_seq %02u", l2cap_channel->expected_tx_seq, l2cap_channel->req_seq); 3169 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3170 if (final){ 3171 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3172 l2cap_channel->tx_send_index = l2cap_channel->tx_read_index; 3173 } 3174 3175 // get SDU 3176 const uint8_t * sdu_data = &packet[COMPLETE_L2CAP_HEADER+2]; 3177 uint16_t sdu_len = size-(COMPLETE_L2CAP_HEADER+2+fcs_size); 3178 3179 // assert SDU size is smaller or equal to our buffers 3180 if (sdu_len > l2cap_channel->local_mps) break; 3181 3182 // check ordering 3183 if (l2cap_channel->expected_tx_seq == tx_seq){ 3184 log_info("Received expected frame with TxSeq == ExpectedTxSeq == %02u", tx_seq); 3185 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3186 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3187 3188 // process SDU 3189 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, sar, sdu_data, sdu_len); 3190 3191 // process stored segments 3192 while (1){ 3193 int index = l2cap_channel->rx_store_index; 3194 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3195 if (!rx_state->valid) break; 3196 3197 log_info("Processing stored frame with TxSeq == ExpectedTxSeq == %02u", l2cap_channel->expected_tx_seq); 3198 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3199 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3200 3201 rx_state->valid = 0; 3202 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, rx_state->sar, &l2cap_channel->rx_packets_data[index], rx_state->len); 3203 3204 // update rx store index 3205 index++; 3206 if (index >= l2cap_channel->num_rx_buffers){ 3207 index = 0; 3208 } 3209 l2cap_channel->rx_store_index = index; 3210 } 3211 3212 // 3213 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3214 3215 } else { 3216 int delta = (tx_seq - l2cap_channel->expected_tx_seq) & 0x3f; 3217 if (delta < 2){ 3218 // store segment 3219 l2cap_ertm_handle_out_of_sequence_sdu(l2cap_channel, sar, delta, sdu_data, sdu_len); 3220 3221 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-SREJ", tx_seq, l2cap_channel->expected_tx_seq); 3222 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3223 } else { 3224 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-REJ", tx_seq, l2cap_channel->expected_tx_seq); 3225 l2cap_channel->send_supervisor_frame_reject = 1; 3226 } 3227 } 3228 } 3229 break; 3230 } 3231 #endif 3232 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3233 } 3234 break; 3235 } 3236 #else 3237 UNUSED(handle); // ok: no code 3238 UNUSED(packet); // ok: no code 3239 UNUSED(size); // ok: no code 3240 #endif 3241 } 3242 3243 static void l2cap_acl_le_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3244 #ifdef ENABLE_BLE 3245 3246 l2cap_fixed_channel_t * l2cap_fixed_channel; 3247 3248 #ifdef ENABLE_LE_DATA_CHANNELS 3249 l2cap_channel_t * l2cap_channel; 3250 #endif 3251 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3252 switch (channel_id) { 3253 3254 case L2CAP_CID_SIGNALING_LE: { 3255 uint16_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1]; 3256 uint16_t len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER + 2); 3257 if (COMPLETE_L2CAP_HEADER + 4 + len > size) break; 3258 int valid = l2cap_le_signaling_handler_dispatch(handle, &packet[COMPLETE_L2CAP_HEADER], sig_id); 3259 if (!valid){ 3260 l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3261 } 3262 break; 3263 } 3264 3265 case L2CAP_CID_ATTRIBUTE_PROTOCOL: 3266 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_ATTRIBUTE_PROTOCOL); 3267 if (!l2cap_fixed_channel) break; 3268 if (!l2cap_fixed_channel->packet_handler) break; 3269 (*l2cap_fixed_channel->packet_handler)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3270 break; 3271 3272 case L2CAP_CID_SECURITY_MANAGER_PROTOCOL: 3273 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3274 if (!l2cap_fixed_channel) break; 3275 if (!l2cap_fixed_channel->packet_handler) break; 3276 (*l2cap_fixed_channel->packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3277 break; 3278 3279 default: 3280 3281 #ifdef ENABLE_LE_DATA_CHANNELS 3282 l2cap_channel = l2cap_get_channel_for_local_cid(channel_id); 3283 if (l2cap_channel) { 3284 // credit counting 3285 if (l2cap_channel->credits_incoming == 0){ 3286 log_error("LE Data Channel packet received but no incoming credits"); 3287 l2cap_channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3288 break; 3289 } 3290 l2cap_channel->credits_incoming--; 3291 3292 // automatic credits 3293 if (l2cap_channel->credits_incoming < L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_WATERMARK && l2cap_channel->automatic_credits){ 3294 l2cap_channel->new_credits_incoming = L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_INCREMENT; 3295 } 3296 3297 // first fragment 3298 uint16_t pos = 0; 3299 if (!l2cap_channel->receive_sdu_len){ 3300 uint16_t sdu_len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3301 if(sdu_len > l2cap_channel->local_mtu) break; // SDU would be larger than our buffer 3302 l2cap_channel->receive_sdu_len = sdu_len; 3303 l2cap_channel->receive_sdu_pos = 0; 3304 pos += 2; 3305 size -= 2; 3306 } 3307 uint16_t fragment_size = size-COMPLETE_L2CAP_HEADER; 3308 uint16_t remaining_space = l2cap_channel->local_mtu - l2cap_channel->receive_sdu_pos; 3309 if (fragment_size > remaining_space) break; // SDU would cause buffer overrun 3310 memcpy(&l2cap_channel->receive_sdu_buffer[l2cap_channel->receive_sdu_pos], &packet[COMPLETE_L2CAP_HEADER+pos], fragment_size); 3311 l2cap_channel->receive_sdu_pos += size - COMPLETE_L2CAP_HEADER; 3312 // done? 3313 log_debug("le packet pos %u, len %u", l2cap_channel->receive_sdu_pos, l2cap_channel->receive_sdu_len); 3314 if (l2cap_channel->receive_sdu_pos >= l2cap_channel->receive_sdu_len){ 3315 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, l2cap_channel->receive_sdu_buffer, l2cap_channel->receive_sdu_len); 3316 l2cap_channel->receive_sdu_len = 0; 3317 } 3318 } else { 3319 log_error("LE Data Channel packet received but no channel found for cid 0x%02x", channel_id); 3320 } 3321 #endif 3322 break; 3323 } 3324 #else 3325 UNUSED(handle); // ok: no code 3326 UNUSED(packet); // ok: no code 3327 UNUSED(size); // ok: no code 3328 #endif 3329 } 3330 3331 static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3332 UNUSED(packet_type); // ok: registered with hci_register_acl_packet_handler 3333 UNUSED(channel); // ok: there is no channel 3334 3335 // Assert full L2CAP header present 3336 if (size < COMPLETE_L2CAP_HEADER) return; 3337 3338 // Dispatch to Classic or LE handler 3339 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 3340 hci_connection_t *conn = hci_connection_for_handle(handle); 3341 if (!conn) return; 3342 if (conn->address_type == BD_ADDR_TYPE_CLASSIC){ 3343 l2cap_acl_classic_handler(handle, packet, size); 3344 } else { 3345 l2cap_acl_le_handler(handle, packet, size); 3346 } 3347 3348 l2cap_run(); 3349 } 3350 3351 // Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol 3352 void l2cap_register_fixed_channel(btstack_packet_handler_t the_packet_handler, uint16_t channel_id) { 3353 l2cap_fixed_channel_t * channel = l2cap_fixed_channel_for_channel_id(channel_id); 3354 if (!channel) return; 3355 channel->packet_handler = the_packet_handler; 3356 } 3357 3358 #ifdef ENABLE_CLASSIC 3359 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 3360 void l2cap_finialize_channel_close(l2cap_channel_t * channel){ 3361 channel->state = L2CAP_STATE_CLOSED; 3362 l2cap_emit_channel_closed(channel); 3363 // discard channel 3364 l2cap_stop_rtx(channel); 3365 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3366 btstack_memory_l2cap_channel_free(channel); 3367 } 3368 #endif 3369 3370 #ifdef L2CAP_USES_CHANNELS 3371 static l2cap_service_t * l2cap_get_service_internal(btstack_linked_list_t * services, uint16_t psm){ 3372 btstack_linked_list_iterator_t it; 3373 btstack_linked_list_iterator_init(&it, services); 3374 while (btstack_linked_list_iterator_has_next(&it)){ 3375 l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it); 3376 if ( service->psm == psm){ 3377 return service; 3378 }; 3379 } 3380 return NULL; 3381 } 3382 #endif 3383 3384 #ifdef ENABLE_CLASSIC 3385 static inline l2cap_service_t * l2cap_get_service(uint16_t psm){ 3386 return l2cap_get_service_internal(&l2cap_services, psm); 3387 } 3388 3389 uint8_t l2cap_register_service(btstack_packet_handler_t service_packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level){ 3390 3391 log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u", psm, mtu); 3392 3393 // check for alread registered psm 3394 l2cap_service_t *service = l2cap_get_service(psm); 3395 if (service) { 3396 log_error("l2cap_register_service: PSM %u already registered", psm); 3397 return L2CAP_SERVICE_ALREADY_REGISTERED; 3398 } 3399 3400 // alloc structure 3401 service = btstack_memory_l2cap_service_get(); 3402 if (!service) { 3403 log_error("l2cap_register_service: no memory for l2cap_service_t"); 3404 return BTSTACK_MEMORY_ALLOC_FAILED; 3405 } 3406 3407 // fill in 3408 service->psm = psm; 3409 service->mtu = mtu; 3410 service->packet_handler = service_packet_handler; 3411 service->required_security_level = security_level; 3412 3413 // add to services list 3414 btstack_linked_list_add(&l2cap_services, (btstack_linked_item_t *) service); 3415 3416 // enable page scan 3417 gap_connectable_control(1); 3418 3419 return 0; 3420 } 3421 3422 uint8_t l2cap_unregister_service(uint16_t psm){ 3423 3424 log_info("L2CAP_UNREGISTER_SERVICE psm 0x%x", psm); 3425 3426 l2cap_service_t *service = l2cap_get_service(psm); 3427 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 3428 btstack_linked_list_remove(&l2cap_services, (btstack_linked_item_t *) service); 3429 btstack_memory_l2cap_service_free(service); 3430 3431 // disable page scan when no services registered 3432 if (btstack_linked_list_empty(&l2cap_services)) { 3433 gap_connectable_control(0); 3434 } 3435 return 0; 3436 } 3437 #endif 3438 3439 3440 #ifdef ENABLE_LE_DATA_CHANNELS 3441 3442 static void l2cap_le_notify_channel_can_send(l2cap_channel_t *channel){ 3443 if (!channel->waiting_for_can_send_now) return; 3444 if (channel->send_sdu_buffer) return; 3445 channel->waiting_for_can_send_now = 0; 3446 log_debug("L2CAP_EVENT_CHANNEL_LE_CAN_SEND_NOW local_cid 0x%x", channel->local_cid); 3447 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_CAN_SEND_NOW); 3448 } 3449 3450 // 1BH2222 3451 static void l2cap_emit_le_incoming_connection(l2cap_channel_t *channel) { 3452 log_info("L2CAP_EVENT_LE_INCOMING_CONNECTION addr_type %u, addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x, remote_mtu %u", 3453 channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, channel->local_cid, channel->remote_cid, channel->remote_mtu); 3454 uint8_t event[19]; 3455 event[0] = L2CAP_EVENT_LE_INCOMING_CONNECTION; 3456 event[1] = sizeof(event) - 2; 3457 event[2] = channel->address_type; 3458 reverse_bd_addr(channel->address, &event[3]); 3459 little_endian_store_16(event, 9, channel->con_handle); 3460 little_endian_store_16(event, 11, channel->psm); 3461 little_endian_store_16(event, 13, channel->local_cid); 3462 little_endian_store_16(event, 15, channel->remote_cid); 3463 little_endian_store_16(event, 17, channel->remote_mtu); 3464 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3465 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 3466 } 3467 // 11BH22222 3468 static void l2cap_emit_le_channel_opened(l2cap_channel_t *channel, uint8_t status) { 3469 log_info("L2CAP_EVENT_LE_CHANNEL_OPENED status 0x%x addr_type %u addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x local_mtu %u, remote_mtu %u", 3470 status, channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, 3471 channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu); 3472 uint8_t event[23]; 3473 event[0] = L2CAP_EVENT_LE_CHANNEL_OPENED; 3474 event[1] = sizeof(event) - 2; 3475 event[2] = status; 3476 event[3] = channel->address_type; 3477 reverse_bd_addr(channel->address, &event[4]); 3478 little_endian_store_16(event, 10, channel->con_handle); 3479 event[12] = channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING ? 1 : 0; 3480 little_endian_store_16(event, 13, channel->psm); 3481 little_endian_store_16(event, 15, channel->local_cid); 3482 little_endian_store_16(event, 17, channel->remote_cid); 3483 little_endian_store_16(event, 19, channel->local_mtu); 3484 little_endian_store_16(event, 21, channel->remote_mtu); 3485 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3486 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 3487 } 3488 // 2 3489 static void l2cap_emit_le_channel_closed(l2cap_channel_t * channel){ 3490 log_info("L2CAP_EVENT_LE_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid); 3491 uint8_t event[4]; 3492 event[0] = L2CAP_EVENT_LE_CHANNEL_CLOSED; 3493 event[1] = sizeof(event) - 2; 3494 little_endian_store_16(event, 2, channel->local_cid); 3495 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3496 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 3497 } 3498 3499 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 3500 void l2cap_le_finialize_channel_close(l2cap_channel_t * channel){ 3501 channel->state = L2CAP_STATE_CLOSED; 3502 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_CHANNEL_CLOSED); 3503 // discard channel 3504 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3505 btstack_memory_l2cap_channel_free(channel); 3506 } 3507 3508 static inline l2cap_service_t * l2cap_le_get_service(uint16_t le_psm){ 3509 return l2cap_get_service_internal(&l2cap_le_services, le_psm); 3510 } 3511 3512 uint8_t l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level){ 3513 3514 log_info("L2CAP_LE_REGISTER_SERVICE psm 0x%x", psm); 3515 3516 // check for alread registered psm 3517 l2cap_service_t *service = l2cap_le_get_service(psm); 3518 if (service) { 3519 return L2CAP_SERVICE_ALREADY_REGISTERED; 3520 } 3521 3522 // alloc structure 3523 service = btstack_memory_l2cap_service_get(); 3524 if (!service) { 3525 log_error("l2cap_register_service_internal: no memory for l2cap_service_t"); 3526 return BTSTACK_MEMORY_ALLOC_FAILED; 3527 } 3528 3529 // fill in 3530 service->psm = psm; 3531 service->mtu = 0; 3532 service->packet_handler = packet_handler; 3533 service->required_security_level = security_level; 3534 3535 // add to services list 3536 btstack_linked_list_add(&l2cap_le_services, (btstack_linked_item_t *) service); 3537 3538 // done 3539 return 0; 3540 } 3541 3542 uint8_t l2cap_le_unregister_service(uint16_t psm) { 3543 log_info("L2CAP_LE_UNREGISTER_SERVICE psm 0x%x", psm); 3544 l2cap_service_t *service = l2cap_le_get_service(psm); 3545 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 3546 3547 btstack_linked_list_remove(&l2cap_le_services, (btstack_linked_item_t *) service); 3548 btstack_memory_l2cap_service_free(service); 3549 return 0; 3550 } 3551 3552 uint8_t l2cap_le_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits){ 3553 // get channel 3554 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3555 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 3556 3557 // validate state 3558 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 3559 return ERROR_CODE_COMMAND_DISALLOWED; 3560 } 3561 3562 // set state accept connection 3563 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT; 3564 channel->receive_sdu_buffer = receive_sdu_buffer; 3565 channel->local_mtu = mtu; 3566 channel->new_credits_incoming = initial_credits; 3567 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 3568 3569 // test 3570 // channel->new_credits_incoming = 1; 3571 3572 // go 3573 l2cap_run(); 3574 return 0; 3575 } 3576 3577 /** 3578 * @brief Deny incoming LE Data Channel connection due to resource constraints 3579 * @param local_cid L2CAP LE Data Channel Identifier 3580 */ 3581 3582 uint8_t l2cap_le_decline_connection(uint16_t local_cid){ 3583 // get channel 3584 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3585 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 3586 3587 // validate state 3588 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 3589 return ERROR_CODE_COMMAND_DISALLOWED; 3590 } 3591 3592 // set state decline connection 3593 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE; 3594 channel->reason = 0x04; // no resources available 3595 l2cap_run(); 3596 return 0; 3597 } 3598 3599 uint8_t l2cap_le_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, 3600 uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level, 3601 uint16_t * out_local_cid) { 3602 3603 log_info("L2CAP_LE_CREATE_CHANNEL handle 0x%04x psm 0x%x mtu %u", con_handle, psm, mtu); 3604 3605 3606 hci_connection_t * connection = hci_connection_for_handle(con_handle); 3607 if (!connection) { 3608 log_error("no hci_connection for handle 0x%04x", con_handle); 3609 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 3610 } 3611 3612 l2cap_channel_t * channel = l2cap_create_channel_entry(packet_handler, L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL, connection->address, connection->address_type, psm, mtu, security_level); 3613 if (!channel) { 3614 return BTSTACK_MEMORY_ALLOC_FAILED; 3615 } 3616 log_info("l2cap_le_create_channel %p", channel); 3617 3618 // store local_cid 3619 if (out_local_cid){ 3620 *out_local_cid = channel->local_cid; 3621 } 3622 3623 // provide buffer 3624 channel->con_handle = con_handle; 3625 channel->receive_sdu_buffer = receive_sdu_buffer; 3626 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST; 3627 channel->new_credits_incoming = initial_credits; 3628 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 3629 3630 // add to connections list 3631 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel); 3632 3633 // go 3634 l2cap_run(); 3635 return 0; 3636 } 3637 3638 /** 3639 * @brief Provide credtis for LE Data Channel 3640 * @param local_cid L2CAP LE Data Channel Identifier 3641 * @param credits Number additional credits for peer 3642 */ 3643 uint8_t l2cap_le_provide_credits(uint16_t local_cid, uint16_t credits){ 3644 3645 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3646 if (!channel) { 3647 log_error("l2cap_le_provide_credits no channel for cid 0x%02x", local_cid); 3648 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 3649 } 3650 3651 // check state 3652 if (channel->state != L2CAP_STATE_OPEN){ 3653 log_error("l2cap_le_provide_credits but channel 0x%02x not open yet", local_cid); 3654 } 3655 3656 // assert incoming credits + credits <= 0xffff 3657 uint32_t total_credits = channel->credits_incoming; 3658 total_credits += channel->new_credits_incoming; 3659 total_credits += credits; 3660 if (total_credits > 0xffff){ 3661 log_error("l2cap_le_provide_credits overrun: current %u, scheduled %u, additional %u", channel->credits_incoming, 3662 channel->new_credits_incoming, credits); 3663 } 3664 3665 // set credits_granted 3666 channel->new_credits_incoming += credits; 3667 3668 // go 3669 l2cap_run(); 3670 return 0; 3671 } 3672 3673 /** 3674 * @brief Check if outgoing buffer is available and that there's space on the Bluetooth module 3675 * @param local_cid L2CAP LE Data Channel Identifier 3676 */ 3677 int l2cap_le_can_send_now(uint16_t local_cid){ 3678 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3679 if (!channel) { 3680 log_error("l2cap_le_provide_credits no channel for cid 0x%02x", local_cid); 3681 return 0; 3682 } 3683 3684 // check state 3685 if (channel->state != L2CAP_STATE_OPEN) return 0; 3686 3687 // check queue 3688 if (channel->send_sdu_buffer) return 0; 3689 3690 // fine, go ahead 3691 return 1; 3692 } 3693 3694 /** 3695 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible 3696 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 3697 * so packet handler should be ready to handle it 3698 * @param local_cid L2CAP LE Data Channel Identifier 3699 */ 3700 uint8_t l2cap_le_request_can_send_now_event(uint16_t local_cid){ 3701 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3702 if (!channel) { 3703 log_error("l2cap_le_request_can_send_now_event no channel for cid 0x%02x", local_cid); 3704 return 0; 3705 } 3706 channel->waiting_for_can_send_now = 1; 3707 l2cap_le_notify_channel_can_send(channel); 3708 return 0; 3709 } 3710 3711 /** 3712 * @brief Send data via LE Data Channel 3713 * @note Since data larger then the maximum PDU needs to be segmented into multiple PDUs, data needs to stay valid until ... event 3714 * @param local_cid L2CAP LE Data Channel Identifier 3715 * @param data data to send 3716 * @param size data size 3717 */ 3718 uint8_t l2cap_le_send_data(uint16_t local_cid, uint8_t * data, uint16_t len){ 3719 3720 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3721 if (!channel) { 3722 log_error("l2cap_send no channel for cid 0x%02x", local_cid); 3723 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 3724 } 3725 3726 if (len > channel->remote_mtu){ 3727 log_error("l2cap_send cid 0x%02x, data length exceeds remote MTU.", local_cid); 3728 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 3729 } 3730 3731 if (channel->send_sdu_buffer){ 3732 log_info("l2cap_send cid 0x%02x, cannot send", local_cid); 3733 return BTSTACK_ACL_BUFFERS_FULL; 3734 } 3735 3736 channel->send_sdu_buffer = data; 3737 channel->send_sdu_len = len; 3738 channel->send_sdu_pos = 0; 3739 3740 l2cap_run(); 3741 return 0; 3742 } 3743 3744 /** 3745 * @brief Disconnect from LE Data Channel 3746 * @param local_cid L2CAP LE Data Channel Identifier 3747 */ 3748 uint8_t l2cap_le_disconnect(uint16_t local_cid) 3749 { 3750 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 3751 if (!channel) { 3752 log_error("l2cap_send no channel for cid 0x%02x", local_cid); 3753 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 3754 } 3755 3756 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3757 l2cap_run(); 3758 return 0; 3759 } 3760 3761 #endif 3762