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 * Logical Link Control and Adaption Protocol (L2CAP) 43 */ 44 45 #include "l2cap.h" 46 #include "hci.h" 47 #include "hci_dump.h" 48 #include "bluetooth_sdp.h" 49 #include "bluetooth_psm.h" 50 #include "btstack_bool.h" 51 #include "btstack_debug.h" 52 #include "btstack_event.h" 53 #include "btstack_memory.h" 54 55 #ifdef ENABLE_LE_DATA_CHANNELS 56 // TODO avoid dependency on higher layer: used to trigger pairing for outgoing connections 57 #include "ble/sm.h" 58 #endif 59 60 #include <stdarg.h> 61 #include <string.h> 62 63 /* 64 * @brief L2CAP Supervisory function in S-Frames 65 */ 66 typedef enum { 67 L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY = 0, 68 L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT, 69 L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY, 70 L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT 71 } l2cap_supervisory_function_t; 72 73 /** 74 * @brief L2CAP Information Types used in Information Request & Response 75 */ 76 typedef enum { 77 L2CAP_INFO_TYPE_CONNECTIONLESS_MTU = 1, 78 L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED, 79 L2CAP_INFO_TYPE_FIXED_CHANNELS_SUPPORTED, 80 } l2cap_info_type_t; 81 82 /** 83 * @brief L2CAP Configuration Option Types used in Configurateion Request & Response 84 */ 85 typedef enum { 86 L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT = 1, 87 L2CAP_CONFIG_OPTION_TYPE_FLUSH_TIMEOUT, 88 L2CAP_CONFIG_OPTION_TYPE_QUALITY_OF_SERVICE, 89 L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL, 90 L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE, 91 L2CAP_CONFIG_OPTION_TYPE_EXTENDED_FLOW_SPECIFICATION, 92 L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE, 93 } l2cap_config_option_type_t; 94 95 96 #define L2CAP_SIG_ID_INVALID 0 97 98 // size of HCI ACL + L2CAP Header for regular data packets (8) 99 #define COMPLETE_L2CAP_HEADER (HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE) 100 101 // L2CAP Configuration Result Codes 102 #define L2CAP_CONF_RESULT_SUCCESS 0x0000 103 #define L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS 0x0001 104 #define L2CAP_CONF_RESULT_REJECT 0x0002 105 #define L2CAP_CONF_RESULT_UNKNOWN_OPTIONS 0x0003 106 #define L2CAP_CONF_RESULT_PENDING 0x0004 107 #define L2CAP_CONF_RESULT_FLOW_SPEC_REJECTED 0x0005 108 109 // L2CAP Reject Result Codes 110 #define L2CAP_REJ_CMD_UNKNOWN 0x0000 111 112 // Response Timeout eXpired 113 #define L2CAP_RTX_TIMEOUT_MS 10000 114 115 // Extended Response Timeout eXpired 116 #define L2CAP_ERTX_TIMEOUT_MS 120000 117 118 // nr of buffered acl packets in outgoing queue to get max performance 119 #define NR_BUFFERED_ACL_PACKETS 3 120 121 // used to cache l2cap rejects, echo, and informational requests 122 #define NR_PENDING_SIGNALING_RESPONSES 3 123 124 // nr of credits provided to remote if credits fall below watermark 125 #define L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_WATERMARK 5 126 #define L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_INCREMENT 5 127 128 // offsets for L2CAP SIGNALING COMMANDS 129 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0 130 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1 131 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2 132 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4 133 134 #if defined(ENABLE_LE_DATA_CHANNELS) || defined(ENABLE_CLASSIC) 135 #define L2CAP_USES_CHANNELS 136 #endif 137 138 // prototypes 139 static void l2cap_run(void); 140 static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size); 141 static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size ); 142 static void l2cap_notify_channel_can_send(void); 143 static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel); 144 static uint8_t l2cap_next_sig_id(void); 145 static l2cap_fixed_channel_t * l2cap_fixed_channel_for_channel_id(uint16_t local_cid); 146 #ifdef ENABLE_CLASSIC 147 static void l2cap_handle_security_level_incoming_sufficient(l2cap_channel_t * channel); 148 static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm); 149 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel); 150 static void l2cap_handle_connection_complete(hci_con_handle_t con_handle, l2cap_channel_t * channel); 151 static void l2cap_finialize_channel_close(l2cap_channel_t *channel); 152 static inline l2cap_service_t * l2cap_get_service(uint16_t psm); 153 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status); 154 static void l2cap_emit_channel_closed(l2cap_channel_t *channel); 155 static void l2cap_emit_incoming_connection(l2cap_channel_t *channel); 156 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel); 157 #endif 158 #ifdef ENABLE_LE_DATA_CHANNELS 159 static void l2cap_emit_le_channel_opened(l2cap_channel_t *channel, uint8_t status); 160 static void l2cap_emit_le_channel_closed(l2cap_channel_t * channel); 161 static void l2cap_emit_le_incoming_connection(l2cap_channel_t *channel); 162 static void l2cap_le_notify_channel_can_send(l2cap_channel_t *channel); 163 static void l2cap_le_finialize_channel_close(l2cap_channel_t *channel); 164 static void l2cap_le_send_pdu(l2cap_channel_t *channel); 165 static inline l2cap_service_t * l2cap_le_get_service(uint16_t psm); 166 #endif 167 #ifdef L2CAP_USES_CHANNELS 168 static uint16_t l2cap_next_local_cid(void); 169 static l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid); 170 static void l2cap_emit_simple_event_with_cid(l2cap_channel_t * channel, uint8_t event_code); 171 static void l2cap_dispatch_to_channel(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size); 172 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, 173 uint16_t psm, uint16_t local_mtu, gap_security_level_t security_level); 174 static void l2cap_free_channel_entry(l2cap_channel_t * channel); 175 #endif 176 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 177 static void l2cap_ertm_notify_channel_can_send(l2cap_channel_t * channel); 178 static void l2cap_ertm_monitor_timeout_callback(btstack_timer_source_t * ts); 179 static void l2cap_ertm_retransmission_timeout_callback(btstack_timer_source_t * ts); 180 #endif 181 182 // l2cap_fixed_channel_t entries 183 #ifdef ENABLE_BLE 184 static l2cap_fixed_channel_t l2cap_fixed_channel_att; 185 static l2cap_fixed_channel_t l2cap_fixed_channel_sm; 186 #endif 187 #ifdef ENABLE_CLASSIC 188 static l2cap_fixed_channel_t l2cap_fixed_channel_connectionless; 189 #endif 190 191 #ifdef ENABLE_CLASSIC 192 static btstack_linked_list_t l2cap_services; 193 static uint8_t l2cap_require_security_level2_for_outgoing_sdp; 194 static bd_addr_t l2cap_outgoing_classic_addr; 195 #endif 196 197 #ifdef ENABLE_LE_DATA_CHANNELS 198 static btstack_linked_list_t l2cap_le_services; 199 #endif 200 201 // single list of channels for Classic Channels, LE Data Channels, Classic Connectionless, ATT, and SM 202 static btstack_linked_list_t l2cap_channels; 203 #ifdef L2CAP_USES_CHANNELS 204 // next channel id for new connections 205 static uint16_t l2cap_local_source_cid; 206 #endif 207 // next signaling sequence number 208 static uint8_t l2cap_sig_seq_nr; 209 210 // used to cache l2cap rejects, echo, and informational requests 211 static l2cap_signaling_response_t l2cap_signaling_responses[NR_PENDING_SIGNALING_RESPONSES]; 212 static int l2cap_signaling_responses_pending; 213 static btstack_packet_callback_registration_t l2cap_hci_event_callback_registration; 214 215 #ifdef ENABLE_BLE 216 // only used for connection parameter update events 217 static btstack_packet_handler_t l2cap_event_packet_handler; 218 static uint16_t l2cap_le_custom_max_mtu; 219 #endif 220 221 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 222 223 // enable for testing 224 // #define L2CAP_ERTM_SIMULATE_FCS_ERROR_INTERVAL 16 225 226 /* 227 * CRC lookup table for generator polynom D^16 + D^15 + D^2 + 1 228 */ 229 static const uint16_t crc16_table[256] = { 230 0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241, 0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440, 231 0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40, 0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841, 232 0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40, 0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41, 233 0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641, 0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040, 234 0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240, 0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441, 235 0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41, 0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840, 236 0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41, 0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40, 237 0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640, 0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041, 238 0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240, 0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441, 239 0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41, 0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840, 240 0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41, 0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40, 241 0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640, 0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041, 242 0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241, 0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440, 243 0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40, 0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841, 244 0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40, 0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41, 245 0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641, 0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040, 246 }; 247 248 static uint16_t crc16_calc(uint8_t * data, uint16_t len){ 249 uint16_t crc = 0; // initial value = 0 250 while (len--){ 251 crc = (crc >> 8) ^ crc16_table[ (crc ^ ((uint16_t) *data++)) & 0x00FF ]; 252 } 253 return crc; 254 } 255 256 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){ 257 return (((uint16_t) sar) << 14) | (req_seq << 8) | (final << 7) | (tx_seq << 1) | 0; 258 } 259 260 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){ 261 return (req_seq << 8) | (final << 7) | (poll << 4) | (((int) supervisory_function) << 2) | 1; 262 } 263 264 static int l2cap_next_ertm_seq_nr(int seq_nr){ 265 return (seq_nr + 1) & 0x3f; 266 } 267 268 static bool l2cap_ertm_can_store_packet_now(l2cap_channel_t * channel){ 269 // get num free tx buffers 270 int num_free_tx_buffers = channel->num_tx_buffers - channel->num_stored_tx_frames; 271 // calculate num tx buffers for remote MTU 272 int num_tx_buffers_for_max_remote_mtu; 273 uint16_t effective_mps = btstack_min(channel->remote_mps, channel->local_mps); 274 if (channel->remote_mtu <= effective_mps){ 275 // MTU fits into single packet 276 num_tx_buffers_for_max_remote_mtu = 1; 277 } else { 278 // include SDU Length 279 num_tx_buffers_for_max_remote_mtu = (channel->remote_mtu + 2 + (effective_mps - 1)) / effective_mps; 280 } 281 log_debug("num_free_tx_buffers %u, num_tx_buffers_for_max_remote_mtu %u", num_free_tx_buffers, num_tx_buffers_for_max_remote_mtu); 282 return num_tx_buffers_for_max_remote_mtu <= num_free_tx_buffers; 283 } 284 285 static void l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel_t * l2cap_channel){ 286 log_info("Retransmit unacknowleged frames"); 287 l2cap_channel->unacked_frames = 0;; 288 l2cap_channel->tx_send_index = l2cap_channel->tx_read_index; 289 } 290 291 static void l2cap_ertm_next_tx_write_index(l2cap_channel_t * channel){ 292 channel->tx_write_index++; 293 if (channel->tx_write_index < channel->num_tx_buffers) return; 294 channel->tx_write_index = 0; 295 } 296 297 static void l2cap_ertm_start_monitor_timer(l2cap_channel_t * channel){ 298 log_info("Start Monitor timer"); 299 btstack_run_loop_remove_timer(&channel->monitor_timer); 300 btstack_run_loop_set_timer_handler(&channel->monitor_timer, &l2cap_ertm_monitor_timeout_callback); 301 btstack_run_loop_set_timer_context(&channel->monitor_timer, channel); 302 btstack_run_loop_set_timer(&channel->monitor_timer, channel->local_monitor_timeout_ms); 303 btstack_run_loop_add_timer(&channel->monitor_timer); 304 } 305 306 static void l2cap_ertm_stop_monitor_timer(l2cap_channel_t * channel){ 307 log_info("Stop Monitor timer"); 308 btstack_run_loop_remove_timer(&channel->monitor_timer); 309 } 310 311 static void l2cap_ertm_start_retransmission_timer(l2cap_channel_t * channel){ 312 log_info("Start Retransmission timer"); 313 btstack_run_loop_remove_timer(&channel->retransmission_timer); 314 btstack_run_loop_set_timer_handler(&channel->retransmission_timer, &l2cap_ertm_retransmission_timeout_callback); 315 btstack_run_loop_set_timer_context(&channel->retransmission_timer, channel); 316 btstack_run_loop_set_timer(&channel->retransmission_timer, channel->local_retransmission_timeout_ms); 317 btstack_run_loop_add_timer(&channel->retransmission_timer); 318 } 319 320 static void l2cap_ertm_stop_retransmission_timer(l2cap_channel_t * l2cap_channel){ 321 log_info("Stop Retransmission timer"); 322 btstack_run_loop_remove_timer(&l2cap_channel->retransmission_timer); 323 } 324 325 static void l2cap_ertm_monitor_timeout_callback(btstack_timer_source_t * ts){ 326 log_info("Monitor timeout"); 327 l2cap_channel_t * l2cap_channel = (l2cap_channel_t *) btstack_run_loop_get_timer_context(ts); 328 329 // TODO: we assume that it's the oldest packet 330 l2cap_ertm_tx_packet_state_t * tx_state; 331 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 332 333 // check retry count 334 if (tx_state->retry_count < l2cap_channel->remote_max_transmit){ 335 // increment retry count 336 tx_state->retry_count++; 337 338 // start retransmit 339 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 340 341 // start monitor timer 342 l2cap_ertm_start_monitor_timer(l2cap_channel); 343 344 // send RR/P=1 345 l2cap_channel->send_supervisor_frame_receiver_ready_poll = 1; 346 } else { 347 log_info("Monitor timer expired & retry count >= max transmit -> disconnect"); 348 l2cap_channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 349 } 350 l2cap_run(); 351 } 352 353 static void l2cap_ertm_retransmission_timeout_callback(btstack_timer_source_t * ts){ 354 log_info("Retransmission timeout"); 355 l2cap_channel_t * l2cap_channel = (l2cap_channel_t *) btstack_run_loop_get_timer_context(ts); 356 357 // TODO: we assume that it's the oldest packet 358 l2cap_ertm_tx_packet_state_t * tx_state; 359 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 360 361 // set retry count = 1 362 tx_state->retry_count = 1; 363 364 // start retransmit 365 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 366 367 // start monitor timer 368 l2cap_ertm_start_monitor_timer(l2cap_channel); 369 370 // send RR/P=1 371 l2cap_channel->send_supervisor_frame_receiver_ready_poll = 1; 372 l2cap_run(); 373 } 374 375 static int l2cap_ertm_send_information_frame(l2cap_channel_t * channel, int index, int final){ 376 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[index]; 377 hci_reserve_packet_buffer(); 378 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 379 uint16_t control = l2cap_encanced_control_field_for_information_frame(tx_state->tx_seq, final, channel->req_seq, tx_state->sar); 380 log_info("I-Frame: control 0x%04x", control); 381 little_endian_store_16(acl_buffer, 8, control); 382 (void)memcpy(&acl_buffer[8 + 2], 383 &channel->tx_packets_data[index * channel->local_mps], 384 tx_state->len); 385 // (re-)start retransmission timer on 386 l2cap_ertm_start_retransmission_timer(channel); 387 // send 388 return l2cap_send_prepared(channel->local_cid, 2 + tx_state->len); 389 } 390 391 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){ 392 // get next index for storing packets 393 int index = channel->tx_write_index; 394 395 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[index]; 396 tx_state->tx_seq = channel->next_tx_seq; 397 tx_state->sar = sar; 398 tx_state->retry_count = 0; 399 400 uint8_t * tx_packet = &channel->tx_packets_data[index * channel->local_mps]; 401 log_debug("index %u, local mps %u, remote mps %u, packet tx %p, len %u", index, channel->local_mps, channel->remote_mps, tx_packet, len); 402 int pos = 0; 403 if (sar == L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU){ 404 little_endian_store_16(tx_packet, 0, sdu_length); 405 pos += 2; 406 } 407 (void)memcpy(&tx_packet[pos], data, len); 408 tx_state->len = pos + len; 409 410 // update 411 channel->num_stored_tx_frames++; 412 channel->next_tx_seq = l2cap_next_ertm_seq_nr(channel->next_tx_seq); 413 l2cap_ertm_next_tx_write_index(channel); 414 415 log_info("l2cap_ertm_store_fragment: tx_read_index %u, tx_write_index %u, num stored %u", channel->tx_read_index, channel->tx_write_index, channel->num_stored_tx_frames); 416 417 } 418 419 static uint8_t l2cap_ertm_send(l2cap_channel_t * channel, uint8_t * data, uint16_t len){ 420 if (len > channel->remote_mtu){ 421 log_error("l2cap_ertm_send cid 0x%02x, data length exceeds remote MTU.", channel->local_cid); 422 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 423 } 424 425 if (!l2cap_ertm_can_store_packet_now(channel)){ 426 log_error("l2cap_ertm_send cid 0x%02x, fragment store full", channel->local_cid); 427 return BTSTACK_ACL_BUFFERS_FULL; 428 } 429 430 // check if it needs to get fragmented 431 uint16_t effective_mps = btstack_min(channel->remote_mps, channel->local_mps); 432 if (len > effective_mps){ 433 // fragmentation needed. 434 l2cap_segmentation_and_reassembly_t sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU; 435 int chunk_len; 436 while (len){ 437 switch (sar){ 438 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 439 chunk_len = effective_mps - 2; // sdu_length 440 l2cap_ertm_store_fragment(channel, sar, len, data, chunk_len); 441 len -= chunk_len; 442 sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU; 443 break; 444 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 445 chunk_len = effective_mps; 446 if (chunk_len >= len){ 447 sar = L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU; 448 chunk_len = len; 449 } 450 l2cap_ertm_store_fragment(channel, sar, len, data, chunk_len); 451 len -= chunk_len; 452 break; 453 default: 454 break; 455 } 456 } 457 458 } else { 459 l2cap_ertm_store_fragment(channel, L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU, 0, data, len); 460 } 461 462 // try to send 463 l2cap_notify_channel_can_send(); 464 return ERROR_CODE_SUCCESS; 465 } 466 467 static uint16_t l2cap_setup_options_ertm_request(l2cap_channel_t * channel, uint8_t * config_options){ 468 int pos = 0; 469 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL; 470 config_options[pos++] = 9; // length 471 config_options[pos++] = (uint8_t) channel->mode; 472 config_options[pos++] = channel->num_rx_buffers; // == TxWindows size 473 config_options[pos++] = channel->local_max_transmit; 474 little_endian_store_16( config_options, pos, channel->local_retransmission_timeout_ms); 475 pos += 2; 476 little_endian_store_16( config_options, pos, channel->local_monitor_timeout_ms); 477 pos += 2; 478 little_endian_store_16( config_options, pos, channel->local_mps); 479 pos += 2; 480 // 481 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; 482 config_options[pos++] = 2; // length 483 little_endian_store_16(config_options, pos, channel->local_mtu); 484 pos += 2; 485 486 // Issue: iOS (e.g. 10.2) uses "No FCS" as default while Core 5.0 specifies "FCS" as default 487 // Workaround: try to actively negotiate FCS option 488 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE; 489 config_options[pos++] = 1; // length 490 config_options[pos++] = channel->fcs_option; 491 return pos; // 11+4+3=18 492 } 493 494 static uint16_t l2cap_setup_options_ertm_response(l2cap_channel_t * channel, uint8_t * config_options){ 495 int pos = 0; 496 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL; 497 config_options[pos++] = 9; // length 498 config_options[pos++] = (uint8_t) channel->mode; 499 // less or equal to remote tx window size 500 config_options[pos++] = btstack_min(channel->num_tx_buffers, channel->remote_tx_window_size); 501 // max transmit in response shall be ignored -> use sender values 502 config_options[pos++] = channel->remote_max_transmit; 503 // A value for the Retransmission time-out shall be sent in a positive Configuration Response 504 // and indicates the value that will be used by the sender of the Configuration Response -> use our value 505 little_endian_store_16( config_options, pos, channel->local_retransmission_timeout_ms); 506 pos += 2; 507 // A value for the Monitor time-out shall be sent in a positive Configuration Response 508 // and indicates the value that will be used by the sender of the Configuration Response -> use our value 509 little_endian_store_16( config_options, pos, channel->local_monitor_timeout_ms); 510 pos += 2; 511 // less or equal to remote mps 512 uint16_t effective_mps = btstack_min(channel->remote_mps, channel->local_mps); 513 little_endian_store_16( config_options, pos, effective_mps); 514 pos += 2; 515 // 516 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; // MTU 517 config_options[pos++] = 2; // length 518 little_endian_store_16(config_options, pos, channel->remote_mtu); 519 pos += 2; 520 #if 0 521 // 522 config_options[pos++] = L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE; 523 config_options[pos++] = 1; // length 524 config_options[pos++] = channel->fcs_option; 525 #endif 526 return pos; // 11+4=15 527 } 528 529 static int l2cap_ertm_send_supervisor_frame(l2cap_channel_t * channel, uint16_t control){ 530 hci_reserve_packet_buffer(); 531 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 532 log_info("S-Frame: control 0x%04x", control); 533 little_endian_store_16(acl_buffer, 8, control); 534 return l2cap_send_prepared(channel->local_cid, 2); 535 } 536 537 static uint8_t l2cap_ertm_validate_local_config(l2cap_ertm_config_t * ertm_config){ 538 539 uint8_t result = ERROR_CODE_SUCCESS; 540 if (ertm_config->max_transmit < 1){ 541 log_error("max_transmit must be >= 1"); 542 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 543 } 544 if (ertm_config->retransmission_timeout_ms < 2000){ 545 log_error("retransmission_timeout_ms must be >= 2000 ms"); 546 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 547 } 548 if (ertm_config->monitor_timeout_ms < 12000){ 549 log_error("monitor_timeout_ms must be >= 12000 ms"); 550 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 551 } 552 if (ertm_config->local_mtu < 48){ 553 log_error("local_mtu must be >= 48"); 554 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 555 } 556 if (ertm_config->num_rx_buffers < 1){ 557 log_error("num_rx_buffers must be >= 1"); 558 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 559 } 560 if (ertm_config->num_tx_buffers < 1){ 561 log_error("num_rx_buffers must be >= 1"); 562 result = ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS; 563 } 564 return result; 565 } 566 567 static void l2cap_ertm_configure_channel(l2cap_channel_t * channel, l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size){ 568 569 channel->mode = L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION; 570 channel->ertm_mandatory = ertm_config->ertm_mandatory; 571 channel->local_max_transmit = ertm_config->max_transmit; 572 channel->local_retransmission_timeout_ms = ertm_config->retransmission_timeout_ms; 573 channel->local_monitor_timeout_ms = ertm_config->monitor_timeout_ms; 574 channel->local_mtu = ertm_config->local_mtu; 575 channel->num_rx_buffers = ertm_config->num_rx_buffers; 576 channel->num_tx_buffers = ertm_config->num_tx_buffers; 577 578 // align buffer to 16-byte boundary to assert l2cap_ertm_rx_packet_state_t is aligned 579 int bytes_till_alignment = 16 - (((uintptr_t) buffer) & 0x0f); 580 buffer += bytes_till_alignment; 581 size -= bytes_till_alignment; 582 583 // setup state buffers - use void cast to avoid -Wcast-align warning 584 uint32_t pos = 0; 585 channel->rx_packets_state = (l2cap_ertm_rx_packet_state_t *) (void *) &buffer[pos]; 586 pos += ertm_config->num_rx_buffers * sizeof(l2cap_ertm_rx_packet_state_t); 587 channel->tx_packets_state = (l2cap_ertm_tx_packet_state_t *) (void *) &buffer[pos]; 588 pos += ertm_config->num_tx_buffers * sizeof(l2cap_ertm_tx_packet_state_t); 589 590 // setup reassembly buffer 591 channel->reassembly_buffer = &buffer[pos]; 592 pos += ertm_config->local_mtu; 593 594 // divide rest of data equally 595 channel->local_mps = (size - pos) / (ertm_config->num_rx_buffers + ertm_config->num_tx_buffers); 596 log_info("Local MPS: %u", channel->local_mps); 597 channel->rx_packets_data = &buffer[pos]; 598 pos += ertm_config->num_rx_buffers * channel->local_mps; 599 channel->tx_packets_data = &buffer[pos]; 600 601 channel->fcs_option = ertm_config->fcs_option; 602 } 603 604 uint8_t l2cap_create_ertm_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm, 605 l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size, uint16_t * out_local_cid){ 606 607 log_info("L2CAP_CREATE_ERTM_CHANNEL addr %s, psm 0x%x, local mtu %u", bd_addr_to_str(address), psm, ertm_config->local_mtu); 608 609 // validate local config 610 uint8_t result = l2cap_ertm_validate_local_config(ertm_config); 611 if (result) return result; 612 613 // determine security level based on psm 614 const gap_security_level_t security_level = l2cap_security_level_0_allowed_for_PSM(psm) ? LEVEL_0 : gap_get_security_level(); 615 616 l2cap_channel_t * channel = l2cap_create_channel_entry(packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, address, BD_ADDR_TYPE_ACL, psm, ertm_config->local_mtu, security_level); 617 if (!channel) { 618 return BTSTACK_MEMORY_ALLOC_FAILED; 619 } 620 621 // configure ERTM 622 l2cap_ertm_configure_channel(channel, ertm_config, buffer, size); 623 624 // add to connections list 625 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 626 627 // store local_cid 628 if (out_local_cid){ 629 *out_local_cid = channel->local_cid; 630 } 631 632 // check if hci connection is already usable 633 hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_ACL); 634 if (conn){ 635 log_info("l2cap_create_channel, hci connection already exists"); 636 l2cap_handle_connection_complete(conn->con_handle, channel); 637 // check if remote supported fearures are already received 638 if (hci_remote_features_available(conn->con_handle)) { 639 l2cap_handle_remote_supported_features_received(channel); 640 } else { 641 hci_remote_features_query(conn->con_handle); 642 }; 643 } 644 645 l2cap_run(); 646 647 return 0; 648 } 649 650 static void l2cap_ertm_notify_channel_can_send(l2cap_channel_t * channel){ 651 if (l2cap_ertm_can_store_packet_now(channel)){ 652 channel->waiting_for_can_send_now = 0; 653 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 654 } 655 } 656 657 uint8_t l2cap_accept_ertm_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_config, uint8_t * buffer, uint32_t size){ 658 659 log_info("L2CAP_ACCEPT_ERTM_CONNECTION local_cid 0x%x", local_cid); 660 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 661 if (!channel) { 662 log_error("l2cap_accept_connection called but local_cid 0x%x not found", local_cid); 663 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 664 } 665 666 // validate local config 667 uint8_t result = l2cap_ertm_validate_local_config(ertm_config); 668 if (result) return result; 669 670 // configure L2CAP ERTM 671 l2cap_ertm_configure_channel(channel, ertm_config, buffer, size); 672 673 // default: continue 674 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 675 676 // verify remote ERTM support 677 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 678 if (connection == NULL) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 679 680 if ((channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) && ((connection->l2cap_state.extended_feature_mask & 0x08) == 0)){ 681 // ERTM not possible, select basic mode and release buffer 682 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 683 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 684 685 // bail if ERTM is mandatory 686 if (channel->ertm_mandatory){ 687 // We chose 'no resources available' for "ERTM mandatory but you don't even know ERTM exists" 688 log_info("ERTM mandatory -> reject connection"); 689 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 690 channel->reason = 0x04; // no resources available 691 } else { 692 log_info("ERTM not supported by remote -> use Basic mode"); 693 } 694 } 695 696 // process 697 l2cap_run(); 698 699 return ERROR_CODE_SUCCESS; 700 } 701 702 uint8_t l2cap_ertm_set_busy(uint16_t local_cid){ 703 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 704 if (!channel) { 705 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 706 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 707 } 708 if (!channel->local_busy){ 709 channel->local_busy = 1; 710 channel->send_supervisor_frame_receiver_not_ready = 1; 711 l2cap_run(); 712 } 713 return ERROR_CODE_SUCCESS; 714 } 715 716 uint8_t l2cap_ertm_set_ready(uint16_t local_cid){ 717 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 718 if (!channel) { 719 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 720 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 721 } 722 if (channel->local_busy){ 723 channel->local_busy = 0; 724 channel->send_supervisor_frame_receiver_ready_poll = 1; 725 l2cap_run(); 726 } 727 return ERROR_CODE_SUCCESS; 728 } 729 730 // Process-ReqSeq 731 static void l2cap_ertm_process_req_seq(l2cap_channel_t * l2cap_channel, uint8_t req_seq){ 732 int num_buffers_acked = 0; 733 l2cap_ertm_tx_packet_state_t * tx_state; 734 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); 735 while (true){ 736 737 // no unack packets left 738 if (l2cap_channel->unacked_frames == 0) { 739 // stop retransmission timer 740 l2cap_ertm_stop_retransmission_timer(l2cap_channel); 741 break; 742 } 743 744 tx_state = &l2cap_channel->tx_packets_state[l2cap_channel->tx_read_index]; 745 // calc delta 746 int delta = (req_seq - tx_state->tx_seq) & 0x03f; 747 if (delta == 0) break; // all packets acknowledged 748 if (delta > l2cap_channel->remote_tx_window_size) break; 749 750 num_buffers_acked++; 751 l2cap_channel->num_stored_tx_frames--; 752 l2cap_channel->unacked_frames--; 753 log_info("RR seq %u => packet with tx_seq %u done", req_seq, tx_state->tx_seq); 754 755 l2cap_channel->tx_read_index++; 756 if (l2cap_channel->tx_read_index >= l2cap_channel->num_rx_buffers){ 757 l2cap_channel->tx_read_index = 0; 758 } 759 } 760 if (num_buffers_acked){ 761 log_info("num_buffers_acked %u", num_buffers_acked); 762 l2cap_ertm_notify_channel_can_send(l2cap_channel); 763 } 764 } 765 766 static l2cap_ertm_tx_packet_state_t * l2cap_ertm_get_tx_state(l2cap_channel_t * l2cap_channel, uint8_t tx_seq){ 767 int i; 768 for (i=0;i<l2cap_channel->num_tx_buffers;i++){ 769 l2cap_ertm_tx_packet_state_t * tx_state = &l2cap_channel->tx_packets_state[i]; 770 if (tx_state->tx_seq == tx_seq) return tx_state; 771 } 772 return NULL; 773 } 774 775 // @param delta number of frames in the future, >= 1 776 // @assumption size <= l2cap_channel->local_mps (checked in l2cap_acl_classic_handler) 777 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){ 778 log_info("Store SDU with delta %u", delta); 779 // get rx state for packet to store 780 int index = l2cap_channel->rx_store_index + delta - 1; 781 if (index > l2cap_channel->num_rx_buffers){ 782 index -= l2cap_channel->num_rx_buffers; 783 } 784 log_info("Index of packet to store %u", index); 785 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 786 // check if buffer is free 787 if (rx_state->valid){ 788 log_error("Packet buffer already used"); 789 return; 790 } 791 rx_state->valid = 1; 792 rx_state->sar = sar; 793 rx_state->len = size; 794 uint8_t * rx_buffer = &l2cap_channel->rx_packets_data[index]; 795 (void)memcpy(rx_buffer, payload, size); 796 } 797 798 // @assumption size <= l2cap_channel->local_mps (checked in l2cap_acl_classic_handler) 799 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){ 800 uint16_t reassembly_sdu_length; 801 switch (sar){ 802 case L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU: 803 // assert total packet size <= our mtu 804 if (size > l2cap_channel->local_mtu) break; 805 // packet complete -> disapatch 806 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, (uint8_t*) payload, size); 807 break; 808 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 809 // read SDU len 810 reassembly_sdu_length = little_endian_read_16(payload, 0); 811 payload += 2; 812 size -= 2; 813 // assert reassembled size <= our mtu 814 if (reassembly_sdu_length > l2cap_channel->local_mtu) break; 815 // store start segment 816 l2cap_channel->reassembly_sdu_length = reassembly_sdu_length; 817 (void)memcpy(&l2cap_channel->reassembly_buffer[0], payload, size); 818 l2cap_channel->reassembly_pos = size; 819 break; 820 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 821 // assert size of reassembled data <= our mtu 822 if (l2cap_channel->reassembly_pos + size > l2cap_channel->local_mtu) break; 823 // store continuation segment 824 (void)memcpy(&l2cap_channel->reassembly_buffer[l2cap_channel->reassembly_pos], 825 payload, size); 826 l2cap_channel->reassembly_pos += size; 827 break; 828 case L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU: 829 // assert size of reassembled data <= our mtu 830 if (l2cap_channel->reassembly_pos + size > l2cap_channel->local_mtu) break; 831 // store continuation segment 832 (void)memcpy(&l2cap_channel->reassembly_buffer[l2cap_channel->reassembly_pos], 833 payload, size); 834 l2cap_channel->reassembly_pos += size; 835 // assert size of reassembled data matches announced sdu length 836 if (l2cap_channel->reassembly_pos != l2cap_channel->reassembly_sdu_length) break; 837 // packet complete -> disapatch 838 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, l2cap_channel->reassembly_buffer, l2cap_channel->reassembly_pos); 839 l2cap_channel->reassembly_pos = 0; 840 break; 841 default: 842 btstack_assert(false); 843 break; 844 } 845 } 846 847 static void l2cap_ertm_channel_send_information_frame(l2cap_channel_t * channel){ 848 channel->unacked_frames++; 849 int index = channel->tx_send_index; 850 channel->tx_send_index++; 851 if (channel->tx_send_index >= channel->num_tx_buffers){ 852 channel->tx_send_index = 0; 853 } 854 l2cap_ertm_send_information_frame(channel, index, 0); // final = 0 855 } 856 857 #endif 858 859 #ifdef L2CAP_USES_CHANNELS 860 static uint16_t l2cap_next_local_cid(void){ 861 do { 862 if (l2cap_local_source_cid == 0xffffu) { 863 l2cap_local_source_cid = 0x40; 864 } else { 865 l2cap_local_source_cid++; 866 } 867 } while (l2cap_get_channel_for_local_cid(l2cap_local_source_cid) != NULL); 868 return l2cap_local_source_cid; 869 } 870 #endif 871 872 static uint8_t l2cap_next_sig_id(void){ 873 if (l2cap_sig_seq_nr == 0xffu) { 874 l2cap_sig_seq_nr = 1; 875 } else { 876 l2cap_sig_seq_nr++; 877 } 878 return l2cap_sig_seq_nr; 879 } 880 881 void l2cap_init(void){ 882 #ifdef L2CAP_USES_CHANNELS 883 l2cap_local_source_cid = 0x40; 884 #endif 885 l2cap_sig_seq_nr = 0xff; 886 887 #ifdef ENABLE_CLASSIC 888 // Setup Connectionless Channel 889 l2cap_fixed_channel_connectionless.local_cid = L2CAP_CID_CONNECTIONLESS_CHANNEL; 890 l2cap_fixed_channel_connectionless.channel_type = L2CAP_CHANNEL_TYPE_CONNECTIONLESS; 891 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_connectionless); 892 #endif 893 894 #ifdef ENABLE_BLE 895 // Setup fixed ATT Channel 896 l2cap_fixed_channel_att.local_cid = L2CAP_CID_ATTRIBUTE_PROTOCOL; 897 l2cap_fixed_channel_att.channel_type = L2CAP_CHANNEL_TYPE_FIXED; 898 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_att); 899 900 // Setup fixed SM Channel 901 l2cap_fixed_channel_sm.local_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; 902 l2cap_fixed_channel_sm.channel_type = L2CAP_CHANNEL_TYPE_FIXED; 903 btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) &l2cap_fixed_channel_sm); 904 #endif 905 906 // 907 // register callback with HCI 908 // 909 l2cap_hci_event_callback_registration.callback = &l2cap_hci_event_handler; 910 hci_add_event_handler(&l2cap_hci_event_callback_registration); 911 912 hci_register_acl_packet_handler(&l2cap_acl_handler); 913 914 #ifndef ENABLE_EXPLICIT_CONNECTABLE_MODE_CONTROL 915 #ifdef ENABLE_CLASSIC 916 gap_connectable_control(0); // no services yet 917 #endif 918 #endif 919 } 920 921 /** 922 * @brief De-Init L2CAP 923 */ 924 void l2cap_deinit(void){ 925 l2cap_channels = NULL; 926 l2cap_signaling_responses_pending = 0; 927 #ifdef ENABLE_CLASSIC 928 l2cap_require_security_level2_for_outgoing_sdp = 0; 929 (void)memset(&l2cap_fixed_channel_connectionless, 0, sizeof(l2cap_fixed_channel_connectionless)); 930 l2cap_services = NULL; 931 (void)memset(l2cap_outgoing_classic_addr, 0, 6); 932 #endif 933 #ifdef ENABLE_BLE 934 l2cap_event_packet_handler = NULL; 935 l2cap_le_custom_max_mtu = 0; 936 (void)memset(&l2cap_fixed_channel_att, 0, sizeof(l2cap_fixed_channel_att)); 937 (void)memset(&l2cap_fixed_channel_sm, 0, sizeof(l2cap_fixed_channel_sm)); 938 #endif 939 #ifdef ENABLE_LE_DATA_CHANNELS 940 l2cap_le_services = NULL; 941 #endif 942 l2cap_signaling_responses_pending = 0; 943 } 944 945 void l2cap_register_packet_handler(void (*handler)(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){ 946 #ifdef ENABLE_BLE 947 l2cap_event_packet_handler = handler; 948 #else 949 UNUSED(handler); // ok: no code 950 #endif 951 } 952 953 void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t channel_id){ 954 UNUSED(con_handle); // ok: there is no con handle 955 956 l2cap_fixed_channel_t * channel = l2cap_fixed_channel_for_channel_id(channel_id); 957 if (!channel) return; 958 channel->waiting_for_can_send_now = 1; 959 l2cap_notify_channel_can_send(); 960 } 961 962 bool l2cap_can_send_fixed_channel_packet_now(hci_con_handle_t con_handle, uint16_t channel_id){ 963 UNUSED(channel_id); // ok: only depends on Controller LE buffers 964 965 return hci_can_send_acl_packet_now(con_handle); 966 } 967 968 uint8_t *l2cap_get_outgoing_buffer(void){ 969 return hci_get_outgoing_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes 970 } 971 972 // only for L2CAP Basic Channels 973 bool l2cap_reserve_packet_buffer(void){ 974 return hci_reserve_packet_buffer(); 975 } 976 977 // only for L2CAP Basic Channels 978 void l2cap_release_packet_buffer(void){ 979 hci_release_packet_buffer(); 980 } 981 982 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){ 983 // 0 - Connection handle : PB=pb : BC=00 984 little_endian_store_16(acl_buffer, 0u, con_handle | (packet_boundary << 12u) | (0u << 14u)); 985 // 2 - ACL length 986 little_endian_store_16(acl_buffer, 2u, len + 4u); 987 // 4 - L2CAP packet length 988 little_endian_store_16(acl_buffer, 4u, len + 0u); 989 // 6 - L2CAP channel DEST 990 little_endian_store_16(acl_buffer, 6, remote_cid); 991 } 992 993 // assumption - only on LE connections 994 uint8_t l2cap_send_prepared_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint16_t len){ 995 996 if (!hci_is_packet_buffer_reserved()){ 997 log_error("l2cap_send_prepared_connectionless called without reserving packet first"); 998 return BTSTACK_ACL_BUFFERS_FULL; 999 } 1000 1001 if (!hci_can_send_prepared_acl_packet_now(con_handle)){ 1002 log_info("l2cap_send_prepared_connectionless handle 0x%02x, cid 0x%02x, cannot send", con_handle, cid); 1003 return BTSTACK_ACL_BUFFERS_FULL; 1004 } 1005 1006 log_debug("l2cap_send_prepared_connectionless handle %u, cid 0x%02x", con_handle, cid); 1007 1008 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1009 l2cap_setup_header(acl_buffer, con_handle, 0, cid, len); 1010 // send 1011 return hci_send_acl_packet_buffer(len+8u); 1012 } 1013 1014 // assumption - only on LE connections 1015 uint8_t l2cap_send_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint8_t *data, uint16_t len){ 1016 1017 if (!hci_can_send_acl_packet_now(con_handle)){ 1018 log_info("l2cap_send cid 0x%02x, cannot send", cid); 1019 return BTSTACK_ACL_BUFFERS_FULL; 1020 } 1021 1022 hci_reserve_packet_buffer(); 1023 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1024 1025 (void)memcpy(&acl_buffer[8], data, len); 1026 1027 return l2cap_send_prepared_connectionless(con_handle, cid, len); 1028 } 1029 1030 static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel) { 1031 log_debug("L2CAP_EVENT_CHANNEL_CAN_SEND_NOW local_cid 0x%x", channel); 1032 uint8_t event[4]; 1033 event[0] = L2CAP_EVENT_CAN_SEND_NOW; 1034 event[1] = sizeof(event) - 2u; 1035 little_endian_store_16(event, 2, channel); 1036 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 1037 packet_handler(HCI_EVENT_PACKET, channel, event, sizeof(event)); 1038 } 1039 1040 #ifdef L2CAP_USES_CHANNELS 1041 static void l2cap_dispatch_to_channel(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){ 1042 (* (channel->packet_handler))(type, channel->local_cid, data, size); 1043 } 1044 1045 static void l2cap_emit_simple_event_with_cid(l2cap_channel_t * channel, uint8_t event_code){ 1046 uint8_t event[4]; 1047 event[0] = event_code; 1048 event[1] = sizeof(event) - 2u; 1049 little_endian_store_16(event, 2, channel->local_cid); 1050 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 1051 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 1052 } 1053 #endif 1054 1055 #ifdef ENABLE_CLASSIC 1056 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) { 1057 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", 1058 status, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, 1059 channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu, channel->flush_timeout); 1060 uint8_t event[26]; 1061 event[0] = L2CAP_EVENT_CHANNEL_OPENED; 1062 event[1] = sizeof(event) - 2; 1063 event[2] = status; 1064 reverse_bd_addr(channel->address, &event[3]); 1065 little_endian_store_16(event, 9, channel->con_handle); 1066 little_endian_store_16(event, 11, channel->psm); 1067 little_endian_store_16(event, 13, channel->local_cid); 1068 little_endian_store_16(event, 15, channel->remote_cid); 1069 little_endian_store_16(event, 17, channel->local_mtu); 1070 little_endian_store_16(event, 19, channel->remote_mtu); 1071 little_endian_store_16(event, 21, channel->flush_timeout); 1072 event[23] = (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) ? 1 : 0; 1073 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1074 log_info("ERTM mode %u, fcs enabled %u", channel->mode, channel->fcs_option); 1075 event[24] = channel->mode; 1076 event[25] = channel->fcs_option; 1077 1078 #else 1079 event[24] = L2CAP_CHANNEL_MODE_BASIC; 1080 event[25] = 0; 1081 #endif 1082 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 1083 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 1084 } 1085 1086 static void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 1087 log_info("L2CAP_EVENT_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid); 1088 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_CHANNEL_CLOSED); 1089 } 1090 1091 static void l2cap_emit_incoming_connection(l2cap_channel_t *channel) { 1092 log_info("L2CAP_EVENT_INCOMING_CONNECTION addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x", 1093 bd_addr_to_str(channel->address), channel->con_handle, channel->psm, channel->local_cid, channel->remote_cid); 1094 uint8_t event[16]; 1095 event[0] = L2CAP_EVENT_INCOMING_CONNECTION; 1096 event[1] = sizeof(event) - 2; 1097 reverse_bd_addr(channel->address, &event[2]); 1098 little_endian_store_16(event, 8, channel->con_handle); 1099 little_endian_store_16(event, 10, channel->psm); 1100 little_endian_store_16(event, 12, channel->local_cid); 1101 little_endian_store_16(event, 14, channel->remote_cid); 1102 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 1103 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 1104 } 1105 1106 static void l2cap_handle_channel_open_failed(l2cap_channel_t * channel, uint8_t status){ 1107 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1108 // emit ertm buffer released, as it's not needed. if in basic mode, it was either not allocated or already released 1109 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1110 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 1111 } 1112 #endif 1113 l2cap_emit_channel_opened(channel, status); 1114 } 1115 1116 static void l2cap_handle_channel_closed(l2cap_channel_t * channel){ 1117 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1118 // emit ertm buffer released, as it's not needed anymore. if in basic mode, it was either not allocated or already released 1119 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1120 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 1121 } 1122 #endif 1123 l2cap_emit_channel_closed(channel); 1124 } 1125 #endif 1126 1127 static l2cap_fixed_channel_t * l2cap_channel_item_by_cid(uint16_t cid){ 1128 btstack_linked_list_iterator_t it; 1129 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1130 while (btstack_linked_list_iterator_has_next(&it)){ 1131 l2cap_fixed_channel_t * channel = (l2cap_fixed_channel_t*) btstack_linked_list_iterator_next(&it); 1132 if (channel->local_cid == cid) { 1133 return channel; 1134 } 1135 } 1136 return NULL; 1137 } 1138 1139 // used for fixed channels in LE (ATT/SM) and Classic (Connectionless Channel). CID < 0x04 1140 static l2cap_fixed_channel_t * l2cap_fixed_channel_for_channel_id(uint16_t local_cid){ 1141 if (local_cid >= 0x40u) return NULL; 1142 return (l2cap_fixed_channel_t*) l2cap_channel_item_by_cid(local_cid); 1143 } 1144 1145 // used for Classic Channels + LE Data Channels. local_cid >= 0x40 1146 #ifdef L2CAP_USES_CHANNELS 1147 static l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){ 1148 if (local_cid < 0x40u) return NULL; 1149 return (l2cap_channel_t*) l2cap_channel_item_by_cid(local_cid); 1150 } 1151 1152 static l2cap_channel_t * l2cap_get_channel_for_local_cid_and_handle(uint16_t local_cid, hci_con_handle_t con_handle){ 1153 if (local_cid < 0x40u) return NULL; 1154 l2cap_channel_t * l2cap_channel = (l2cap_channel_t*) l2cap_channel_item_by_cid(local_cid); 1155 if (l2cap_channel == NULL) return NULL; 1156 if (l2cap_channel->con_handle != con_handle) return NULL; 1157 return l2cap_channel; 1158 } 1159 #endif 1160 1161 #ifdef ENABLE_CLASSIC 1162 void l2cap_request_can_send_now_event(uint16_t local_cid){ 1163 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 1164 if (!channel) return; 1165 channel->waiting_for_can_send_now = 1; 1166 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1167 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1168 l2cap_ertm_notify_channel_can_send(channel); 1169 return; 1170 } 1171 #endif 1172 l2cap_notify_channel_can_send(); 1173 } 1174 1175 bool l2cap_can_send_packet_now(uint16_t local_cid){ 1176 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 1177 if (!channel) return false; 1178 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1179 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1180 return l2cap_ertm_can_store_packet_now(channel); 1181 } 1182 #endif 1183 return hci_can_send_acl_packet_now(channel->con_handle); 1184 } 1185 1186 bool l2cap_can_send_prepared_packet_now(uint16_t local_cid){ 1187 l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid); 1188 if (!channel) return false; 1189 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1190 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1191 return false; 1192 } 1193 #endif 1194 return hci_can_send_prepared_acl_packet_now(channel->con_handle); 1195 } 1196 1197 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){ 1198 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1199 if (channel) { 1200 return channel->remote_mtu; 1201 } 1202 return 0; 1203 } 1204 #endif 1205 1206 #ifdef L2CAP_USES_CHANNELS 1207 static int l2cap_is_dynamic_channel_type(l2cap_channel_type_t channel_type){ 1208 switch (channel_type){ 1209 case L2CAP_CHANNEL_TYPE_CLASSIC: 1210 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 1211 return 1; 1212 default: 1213 return 0; 1214 } 1215 } 1216 #endif 1217 1218 #ifdef ENABLE_CLASSIC 1219 // RTX Timer only exist for dynamic channels 1220 static l2cap_channel_t * l2cap_channel_for_rtx_timer(btstack_timer_source_t * ts){ 1221 btstack_linked_list_iterator_t it; 1222 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1223 while (btstack_linked_list_iterator_has_next(&it)){ 1224 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1225 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 1226 if (&channel->rtx == ts) { 1227 return channel; 1228 } 1229 } 1230 return NULL; 1231 } 1232 1233 static void l2cap_rtx_timeout(btstack_timer_source_t * ts){ 1234 l2cap_channel_t * channel = l2cap_channel_for_rtx_timer(ts); 1235 if (!channel) return; 1236 1237 log_info("l2cap_rtx_timeout for local cid 0x%02x", channel->local_cid); 1238 1239 // "When terminating the channel, it is not necessary to send a L2CAP_DisconnectReq 1240 // and enter WAIT_DISCONNECT state. Channels can be transitioned directly to the CLOSED state." 1241 // notify client 1242 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_RTX_TIMEOUT); 1243 1244 // discard channel 1245 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1246 l2cap_free_channel_entry(channel); 1247 } 1248 1249 #endif 1250 1251 #ifdef L2CAP_USES_CHANNELS 1252 static void l2cap_stop_rtx(l2cap_channel_t * channel){ 1253 log_info("l2cap_stop_rtx for local cid 0x%02x", channel->local_cid); 1254 btstack_run_loop_remove_timer(&channel->rtx); 1255 } 1256 #endif 1257 1258 static uint8_t l2cap_send_signaling_packet(hci_con_handle_t handle, uint8_t pb_flags, uint16_t cid, L2CAP_SIGNALING_COMMANDS cmd, int identifier, va_list argptr){ 1259 if (!hci_can_send_acl_packet_now(handle)){ 1260 log_info("l2cap_send_classic_signaling_packet, cannot send"); 1261 return BTSTACK_ACL_BUFFERS_FULL; 1262 } 1263 hci_reserve_packet_buffer(); 1264 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1265 uint16_t len = l2cap_create_signaling_packet(acl_buffer, handle, pb_flags, cid, cmd, identifier, argptr); 1266 va_end(argptr); 1267 return hci_send_acl_packet_buffer(len); 1268 } 1269 1270 #ifdef ENABLE_CLASSIC 1271 1272 static void l2cap_start_rtx(l2cap_channel_t * channel){ 1273 l2cap_stop_rtx(channel); 1274 log_info("l2cap_start_rtx for local cid 0x%02x", channel->local_cid); 1275 btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout); 1276 btstack_run_loop_set_timer(&channel->rtx, L2CAP_RTX_TIMEOUT_MS); 1277 btstack_run_loop_add_timer(&channel->rtx); 1278 } 1279 1280 static void l2cap_start_ertx(l2cap_channel_t * channel){ 1281 log_info("l2cap_start_ertx for local cid 0x%02x", channel->local_cid); 1282 l2cap_stop_rtx(channel); 1283 btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout); 1284 btstack_run_loop_set_timer(&channel->rtx, L2CAP_ERTX_TIMEOUT_MS); 1285 btstack_run_loop_add_timer(&channel->rtx); 1286 } 1287 1288 void l2cap_require_security_level_2_for_outgoing_sdp(void){ 1289 l2cap_require_security_level2_for_outgoing_sdp = 1; 1290 } 1291 1292 static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm){ 1293 return (psm == BLUETOOTH_PSM_SDP) && (!l2cap_require_security_level2_for_outgoing_sdp); 1294 } 1295 1296 static int l2cap_send_classic_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, int identifier, ...){ 1297 va_list argptr; 1298 va_start(argptr, identifier); 1299 uint8_t pb_flags = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02; 1300 uint8_t result = l2cap_send_signaling_packet(handle, pb_flags, L2CAP_CID_SIGNALING, cmd, identifier, argptr); 1301 va_end(argptr); 1302 return result; 1303 } 1304 1305 // assumption - only on Classic connections 1306 // cannot be used for L2CAP ERTM 1307 uint8_t l2cap_send_prepared(uint16_t local_cid, uint16_t len){ 1308 1309 if (!hci_is_packet_buffer_reserved()){ 1310 log_error("l2cap_send_prepared called without reserving packet first"); 1311 return BTSTACK_ACL_BUFFERS_FULL; 1312 } 1313 1314 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1315 if (!channel) { 1316 log_error("l2cap_send_prepared no channel for cid 0x%02x", local_cid); 1317 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 1318 } 1319 1320 if (!hci_can_send_prepared_acl_packet_now(channel->con_handle)){ 1321 log_info("l2cap_send_prepared cid 0x%02x, cannot send", local_cid); 1322 return BTSTACK_ACL_BUFFERS_FULL; 1323 } 1324 1325 log_debug("l2cap_send_prepared cid 0x%02x, handle %u, 1 credit used", local_cid, channel->con_handle); 1326 1327 int fcs_size = 0; 1328 1329 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1330 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION && channel->fcs_option){ 1331 fcs_size = 2; 1332 } 1333 #endif 1334 1335 // set non-flushable packet boundary flag if supported on Controller 1336 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1337 uint8_t packet_boundary_flag = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02; 1338 l2cap_setup_header(acl_buffer, channel->con_handle, packet_boundary_flag, channel->remote_cid, len + fcs_size); 1339 1340 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1341 if (fcs_size){ 1342 // calculate FCS over l2cap data 1343 uint16_t fcs = crc16_calc(acl_buffer + 4, 4 + len); 1344 log_info("I-Frame: fcs 0x%04x", fcs); 1345 little_endian_store_16(acl_buffer, 8 + len, fcs); 1346 } 1347 #endif 1348 1349 // send 1350 return hci_send_acl_packet_buffer(len+8+fcs_size); 1351 } 1352 1353 // assumption - only on Classic connections 1354 uint8_t l2cap_send(uint16_t local_cid, uint8_t *data, uint16_t len){ 1355 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 1356 if (!channel) { 1357 log_error("l2cap_send no channel for cid 0x%02x", local_cid); 1358 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 1359 } 1360 1361 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1362 // send in ERTM 1363 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1364 return l2cap_ertm_send(channel, data, len); 1365 } 1366 #endif 1367 1368 if (len > channel->remote_mtu){ 1369 log_error("l2cap_send cid 0x%02x, data length exceeds remote MTU.", local_cid); 1370 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 1371 } 1372 1373 if (!hci_can_send_acl_packet_now(channel->con_handle)){ 1374 log_info("l2cap_send cid 0x%02x, cannot send", local_cid); 1375 return BTSTACK_ACL_BUFFERS_FULL; 1376 } 1377 1378 hci_reserve_packet_buffer(); 1379 uint8_t *acl_buffer = hci_get_outgoing_packet_buffer(); 1380 (void)memcpy(&acl_buffer[8], data, len); 1381 return l2cap_send_prepared(local_cid, len); 1382 } 1383 1384 int l2cap_send_echo_request(hci_con_handle_t con_handle, uint8_t *data, uint16_t len){ 1385 return l2cap_send_classic_signaling_packet(con_handle, ECHO_REQUEST, l2cap_next_sig_id(), len, data); 1386 } 1387 1388 static inline void channelStateVarSetFlag(l2cap_channel_t *channel, uint16_t flag){ 1389 channel->state_var = channel->state_var | flag; 1390 } 1391 1392 static inline void channelStateVarClearFlag(l2cap_channel_t *channel, uint16_t flag){ 1393 channel->state_var = channel->state_var & ~flag; 1394 } 1395 #endif 1396 1397 1398 #ifdef ENABLE_BLE 1399 static int l2cap_send_le_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, int identifier, ...){ 1400 va_list argptr; 1401 va_start(argptr, identifier); 1402 uint8_t pb_flags = 0x00; // First non-automatically-flushable packet of a higher layer message 1403 uint8_t result = l2cap_send_signaling_packet(handle, pb_flags, L2CAP_CID_SIGNALING, cmd, identifier, argptr); 1404 va_end(argptr); 1405 return result; 1406 } 1407 #endif 1408 1409 uint16_t l2cap_max_mtu(void){ 1410 return HCI_ACL_PAYLOAD_SIZE - L2CAP_HEADER_SIZE; 1411 } 1412 1413 #ifdef ENABLE_BLE 1414 uint16_t l2cap_max_le_mtu(void){ 1415 if (l2cap_le_custom_max_mtu != 0u) return l2cap_le_custom_max_mtu; 1416 return l2cap_max_mtu(); 1417 } 1418 1419 void l2cap_set_max_le_mtu(uint16_t max_mtu){ 1420 if (max_mtu < l2cap_max_mtu()){ 1421 l2cap_le_custom_max_mtu = max_mtu; 1422 } 1423 } 1424 #endif 1425 1426 #ifdef ENABLE_CLASSIC 1427 1428 static uint16_t l2cap_setup_options_mtu(uint8_t * config_options, uint16_t mtu){ 1429 config_options[0] = L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT; // MTU 1430 config_options[1] = 2; // len param 1431 little_endian_store_16(config_options, 2, mtu); 1432 return 4; 1433 } 1434 1435 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1436 static int l2cap_ertm_mode(l2cap_channel_t * channel){ 1437 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 1438 return ((connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE) 1439 && (connection->l2cap_state.extended_feature_mask & 0x08)); 1440 } 1441 #endif 1442 1443 static uint16_t l2cap_setup_options_request(l2cap_channel_t * channel, uint8_t * config_options){ 1444 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1445 // use ERTM options if supported by remote and channel ready to use it 1446 if (l2cap_ertm_mode(channel) && channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1447 return l2cap_setup_options_ertm_request(channel, config_options); 1448 } 1449 #endif 1450 uint16_t mtu = channel->local_mtu; 1451 return l2cap_setup_options_mtu(config_options, mtu); 1452 } 1453 1454 static uint16_t l2cap_setup_options_mtu_response(l2cap_channel_t * channel, uint8_t * config_options){ 1455 uint16_t mtu = btstack_min(channel->local_mtu, channel->remote_mtu); 1456 return l2cap_setup_options_mtu(config_options, mtu); 1457 } 1458 1459 static uint32_t l2cap_extended_features_mask(void){ 1460 // extended features request supported, features: fixed channels, unicast connectionless data reception 1461 uint32_t features = 0x280; 1462 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1463 features |= 0x0028; 1464 #endif 1465 return features; 1466 } 1467 #endif 1468 1469 // 1470 #ifdef ENABLE_CLASSIC 1471 1472 // returns true if channel was finalized 1473 static bool l2cap_run_for_classic_channel(l2cap_channel_t * channel){ 1474 1475 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1476 uint8_t config_options[18]; 1477 #else 1478 uint8_t config_options[10]; 1479 #endif 1480 1481 switch (channel->state){ 1482 1483 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 1484 case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT: 1485 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1486 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND) { 1487 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND); 1488 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONN_RESP_PEND); 1489 l2cap_send_classic_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, 1490 channel->local_cid, channel->remote_cid, 1, 0); 1491 } 1492 break; 1493 1494 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 1495 if (!hci_can_send_command_packet_now()) break; 1496 // send connection request - set state first 1497 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE; 1498 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 1499 (void)memcpy(l2cap_outgoing_classic_addr, channel->address, 6); 1500 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, hci_get_allow_role_switch()); 1501 break; 1502 1503 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 1504 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1505 channel->state = L2CAP_STATE_INVALID; 1506 l2cap_send_classic_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, 1507 channel->local_cid, channel->remote_cid, channel->reason, 0); 1508 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 1509 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1510 l2cap_free_channel_entry(channel); 1511 channel = NULL; 1512 break; 1513 1514 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 1515 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1516 channel->state = L2CAP_STATE_CONFIG; 1517 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 1518 l2cap_send_classic_signaling_packet(channel->con_handle, CONNECTION_RESPONSE, channel->remote_sig_id, 1519 channel->local_cid, channel->remote_cid, 0, 0); 1520 break; 1521 1522 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 1523 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1524 // success, start l2cap handshake 1525 channel->local_sig_id = l2cap_next_sig_id(); 1526 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP; 1527 l2cap_send_classic_signaling_packet(channel->con_handle, CONNECTION_REQUEST, channel->local_sig_id, 1528 channel->psm, channel->local_cid); 1529 l2cap_start_rtx(channel); 1530 break; 1531 1532 case L2CAP_STATE_CONFIG: 1533 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1534 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1535 // fallback to basic mode if ERTM requested but not not supported by remote 1536 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 1537 if (!l2cap_ertm_mode(channel)){ 1538 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 1539 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 1540 } 1541 } 1542 #endif 1543 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){ 1544 uint16_t flags = 0; 1545 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 1546 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT) { 1547 flags = 1; 1548 } else { 1549 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1550 } 1551 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID){ 1552 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1553 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, 1554 channel->remote_cid, flags, L2CAP_CONF_RESULT_UNKNOWN_OPTIONS, 1555 1, &channel->unknown_option); 1556 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1557 } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED){ 1558 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED); 1559 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP); 1560 uint16_t options_size = l2cap_setup_options_ertm_response(channel, config_options); 1561 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, 1562 channel->remote_cid, flags, 1563 L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS, options_size, 1564 &config_options); 1565 } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM){ 1566 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM); 1567 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 1568 uint16_t options_size = l2cap_setup_options_ertm_response(channel, config_options); 1569 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, 1570 channel->remote_cid, flags, L2CAP_CONF_RESULT_SUCCESS, 1571 options_size, &config_options); 1572 #endif 1573 } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU){ 1574 channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 1575 uint16_t options_size = l2cap_setup_options_mtu_response(channel, config_options); 1576 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, 1577 channel->remote_cid, flags, L2CAP_CONF_RESULT_SUCCESS, 1578 options_size, &config_options); 1579 } else { 1580 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_RESPONSE, channel->remote_sig_id, 1581 channel->remote_cid, flags, L2CAP_CONF_RESULT_SUCCESS, 0, NULL); 1582 } 1583 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT); 1584 } 1585 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){ 1586 channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 1587 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ); 1588 channel->local_sig_id = l2cap_next_sig_id(); 1589 uint16_t options_size = l2cap_setup_options_request(channel, config_options); 1590 l2cap_send_classic_signaling_packet(channel->con_handle, CONFIGURE_REQUEST, channel->local_sig_id, 1591 channel->remote_cid, 0, options_size, &config_options); 1592 l2cap_start_rtx(channel); 1593 } 1594 if (l2cap_channel_ready_for_open(channel)){ 1595 channel->state = L2CAP_STATE_OPEN; 1596 l2cap_emit_channel_opened(channel, 0); // success 1597 } 1598 break; 1599 1600 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 1601 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1602 channel->state = L2CAP_STATE_INVALID; 1603 l2cap_send_classic_signaling_packet(channel->con_handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, 1604 channel->local_cid, channel->remote_cid); 1605 // 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 :) 1606 l2cap_finialize_channel_close(channel); // -- remove from list 1607 channel = NULL; 1608 break; 1609 1610 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 1611 if (!hci_can_send_acl_packet_now(channel->con_handle)) return false; 1612 channel->local_sig_id = l2cap_next_sig_id(); 1613 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 1614 l2cap_send_classic_signaling_packet(channel->con_handle, DISCONNECTION_REQUEST, channel->local_sig_id, 1615 channel->remote_cid, channel->local_cid); 1616 break; 1617 default: 1618 break; 1619 } 1620 1621 // handle channel finalize on L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE and L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE 1622 return channel == NULL; 1623 } 1624 1625 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1626 static void l2cap_run_for_classic_channel_ertm(l2cap_channel_t * channel){ 1627 1628 // ERTM mode 1629 if (channel->mode != L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) return; 1630 1631 // check if we can still send 1632 if (channel->con_handle == HCI_CON_HANDLE_INVALID) return; 1633 if (!hci_can_send_acl_packet_now(channel->con_handle)) return; 1634 1635 if (channel->send_supervisor_frame_receiver_ready){ 1636 channel->send_supervisor_frame_receiver_ready = 0; 1637 log_info("Send S-Frame: RR %u, final %u", channel->req_seq, channel->set_final_bit_after_packet_with_poll_bit_set); 1638 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); 1639 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1640 l2cap_ertm_send_supervisor_frame(channel, control); 1641 return; 1642 } 1643 if (channel->send_supervisor_frame_receiver_ready_poll){ 1644 channel->send_supervisor_frame_receiver_ready_poll = 0; 1645 log_info("Send S-Frame: RR %u with poll=1 ", channel->req_seq); 1646 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY, 1, 0, channel->req_seq); 1647 l2cap_ertm_send_supervisor_frame(channel, control); 1648 return; 1649 } 1650 if (channel->send_supervisor_frame_receiver_not_ready){ 1651 channel->send_supervisor_frame_receiver_not_ready = 0; 1652 log_info("Send S-Frame: RNR %u", channel->req_seq); 1653 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY, 0, 0, channel->req_seq); 1654 l2cap_ertm_send_supervisor_frame(channel, control); 1655 return; 1656 } 1657 if (channel->send_supervisor_frame_reject){ 1658 channel->send_supervisor_frame_reject = 0; 1659 log_info("Send S-Frame: REJ %u", channel->req_seq); 1660 uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT, 0, 0, channel->req_seq); 1661 l2cap_ertm_send_supervisor_frame(channel, control); 1662 return; 1663 } 1664 if (channel->send_supervisor_frame_selective_reject){ 1665 channel->send_supervisor_frame_selective_reject = 0; 1666 log_info("Send S-Frame: SREJ %u", channel->expected_tx_seq); 1667 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); 1668 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1669 l2cap_ertm_send_supervisor_frame(channel, control); 1670 return; 1671 } 1672 1673 if (channel->srej_active){ 1674 int i; 1675 for (i=0;i<channel->num_tx_buffers;i++){ 1676 l2cap_ertm_tx_packet_state_t * tx_state = &channel->tx_packets_state[i]; 1677 if (tx_state->retransmission_requested) { 1678 tx_state->retransmission_requested = 0; 1679 uint8_t final = channel->set_final_bit_after_packet_with_poll_bit_set; 1680 channel->set_final_bit_after_packet_with_poll_bit_set = 0; 1681 l2cap_ertm_send_information_frame(channel, i, final); 1682 break; 1683 } 1684 } 1685 if (i == channel->num_tx_buffers){ 1686 // no retransmission request found 1687 channel->srej_active = 0; 1688 } else { 1689 // packet was sent 1690 return; 1691 } 1692 } 1693 } 1694 #endif /* ERTM */ 1695 #endif /* Classic */ 1696 1697 static void l2cap_run_signaling_response(void) { 1698 1699 // check pending signaling responses 1700 while (l2cap_signaling_responses_pending){ 1701 1702 hci_con_handle_t handle = l2cap_signaling_responses[0].handle; 1703 1704 if (!hci_can_send_acl_packet_now(handle)) break; 1705 1706 uint8_t sig_id = l2cap_signaling_responses[0].sig_id; 1707 uint8_t response_code = l2cap_signaling_responses[0].code; 1708 uint16_t result = l2cap_signaling_responses[0].data; // CONNECTION_REQUEST, COMMAND_REJECT, REJECT_SM_PAIRING 1709 uint8_t buffer[2]; // REJECT_SM_PAIRING 1710 #ifdef ENABLE_CLASSIC 1711 uint16_t info_type = l2cap_signaling_responses[0].data; // INFORMATION_REQUEST 1712 #endif 1713 uint16_t source_cid = l2cap_signaling_responses[0].cid; // CONNECTION_REQUEST, REJECT_SM_PAIRING 1714 1715 // remove first item before sending (to avoid sending response mutliple times) 1716 l2cap_signaling_responses_pending--; 1717 int i; 1718 for (i=0; i < l2cap_signaling_responses_pending; i++){ 1719 (void)memcpy(&l2cap_signaling_responses[i], 1720 &l2cap_signaling_responses[i + 1], 1721 sizeof(l2cap_signaling_response_t)); 1722 } 1723 1724 switch (response_code){ 1725 #ifdef ENABLE_CLASSIC 1726 case CONNECTION_REQUEST: 1727 l2cap_send_classic_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, source_cid, 0, result, 0); 1728 break; 1729 case ECHO_REQUEST: 1730 l2cap_send_classic_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL); 1731 break; 1732 case INFORMATION_REQUEST: 1733 switch (info_type){ 1734 case L2CAP_INFO_TYPE_CONNECTIONLESS_MTU: { 1735 uint16_t connectionless_mtu = hci_max_acl_data_packet_length(); 1736 l2cap_send_classic_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, 1737 sizeof(connectionless_mtu), &connectionless_mtu); 1738 } 1739 break; 1740 case L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED: { 1741 uint32_t features = l2cap_extended_features_mask(); 1742 l2cap_send_classic_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, 1743 sizeof(features), &features); 1744 } 1745 break; 1746 case L2CAP_INFO_TYPE_FIXED_CHANNELS_SUPPORTED: { 1747 uint8_t map[8]; 1748 memset(map, 0, 8); 1749 // L2CAP Signaling Channel (bit 1) + Connectionless reception (bit 2) 1750 map[0] = (1 << 1) | (1 << 2); 1751 #ifdef ENABLE_BLE 1752 // BR/EDR Security Manager (bit 7) 1753 map[0] |= (1 << 7); 1754 #endif 1755 l2cap_send_classic_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 0, 1756 sizeof(map), &map); 1757 } 1758 break; 1759 default: 1760 // all other types are not supported 1761 l2cap_send_classic_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, info_type, 1, 0, NULL); 1762 break; 1763 } 1764 break; 1765 case COMMAND_REJECT: 1766 l2cap_send_classic_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL); 1767 break; 1768 #endif 1769 #ifdef ENABLE_BLE 1770 case LE_CREDIT_BASED_CONNECTION_REQUEST: 1771 l2cap_send_le_signaling_packet(handle, LE_CREDIT_BASED_CONNECTION_RESPONSE, sig_id, 0, 0, 0, 0, result); 1772 break; 1773 case COMMAND_REJECT_LE: 1774 l2cap_send_le_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL); 1775 break; 1776 #endif 1777 case SM_PAIRING_FAILED: 1778 buffer[0] = SM_CODE_PAIRING_FAILED; 1779 buffer[1] = result; 1780 l2cap_send_connectionless(handle, source_cid, buffer, 2); 1781 break; 1782 default: 1783 // should not happen 1784 break; 1785 } 1786 } 1787 } 1788 1789 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1790 static bool l2ap_run_ertm(void){ 1791 // send l2cap information request if neccessary 1792 btstack_linked_list_iterator_t it; 1793 hci_connections_get_iterator(&it); 1794 while(btstack_linked_list_iterator_has_next(&it)){ 1795 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1796 if (connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST){ 1797 if (!hci_can_send_acl_packet_now(connection->con_handle)) break; 1798 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W4_EXTENDED_FEATURE_RESPONSE; 1799 uint8_t sig_id = l2cap_next_sig_id(); 1800 uint8_t info_type = L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED; 1801 l2cap_send_classic_signaling_packet(connection->con_handle, INFORMATION_REQUEST, sig_id, info_type); 1802 return true; 1803 } 1804 } 1805 return false; 1806 } 1807 #endif 1808 1809 #ifdef ENABLE_LE_DATA_CHANNELS 1810 static void l2cap_run_le_data_channels(void){ 1811 btstack_linked_list_iterator_t it; 1812 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1813 while (btstack_linked_list_iterator_has_next(&it)){ 1814 uint16_t mps; 1815 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1816 1817 if (channel->channel_type != L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL) continue; 1818 1819 // log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var); 1820 switch (channel->state){ 1821 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST: 1822 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1823 channel->state = L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE; 1824 // le psm, source cid, mtu, mps, initial credits 1825 channel->local_sig_id = l2cap_next_sig_id(); 1826 channel->credits_incoming = channel->new_credits_incoming; 1827 channel->new_credits_incoming = 0; 1828 mps = btstack_min(l2cap_max_le_mtu(), channel->local_mtu); 1829 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); 1830 break; 1831 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT: 1832 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1833 // TODO: support larger MPS 1834 channel->state = L2CAP_STATE_OPEN; 1835 channel->credits_incoming = channel->new_credits_incoming; 1836 channel->new_credits_incoming = 0; 1837 mps = btstack_min(l2cap_max_le_mtu(), channel->local_mtu); 1838 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); 1839 // notify client 1840 l2cap_emit_le_channel_opened(channel, 0); 1841 break; 1842 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE: 1843 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1844 channel->state = L2CAP_STATE_INVALID; 1845 l2cap_send_le_signaling_packet(channel->con_handle, LE_CREDIT_BASED_CONNECTION_RESPONSE, channel->remote_sig_id, 0, 0, 0, 0, channel->reason); 1846 // discard channel - l2cap_finialize_channel_close without sending l2cap close event 1847 btstack_linked_list_iterator_remove(&it); 1848 l2cap_free_channel_entry(channel); 1849 break; 1850 case L2CAP_STATE_OPEN: 1851 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1852 1853 // send credits 1854 if (channel->new_credits_incoming){ 1855 log_info("l2cap: sending %u credits", channel->new_credits_incoming); 1856 channel->local_sig_id = l2cap_next_sig_id(); 1857 uint16_t new_credits = channel->new_credits_incoming; 1858 channel->new_credits_incoming = 0; 1859 channel->credits_incoming += new_credits; 1860 l2cap_send_le_signaling_packet(channel->con_handle, LE_FLOW_CONTROL_CREDIT, channel->local_sig_id, channel->remote_cid, new_credits); 1861 } 1862 break; 1863 1864 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 1865 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1866 channel->local_sig_id = l2cap_next_sig_id(); 1867 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 1868 l2cap_send_le_signaling_packet( channel->con_handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid); 1869 break; 1870 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 1871 if (!hci_can_send_acl_packet_now(channel->con_handle)) break; 1872 channel->state = L2CAP_STATE_INVALID; 1873 l2cap_send_le_signaling_packet( channel->con_handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid); 1874 l2cap_le_finialize_channel_close(channel); // -- remove from list 1875 break; 1876 default: 1877 break; 1878 } 1879 } 1880 } 1881 #endif 1882 1883 // MARK: L2CAP_RUN 1884 // process outstanding signaling tasks 1885 static void l2cap_run(void){ 1886 1887 // log_info("l2cap_run: entered"); 1888 l2cap_run_signaling_response(); 1889 1890 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1891 bool done = l2ap_run_ertm(); 1892 if (done) return; 1893 #endif 1894 1895 #if defined(ENABLE_CLASSIC) || defined(ENABLE_BLE) 1896 btstack_linked_list_iterator_t it; 1897 #endif 1898 1899 #ifdef ENABLE_CLASSIC 1900 btstack_linked_list_iterator_init(&it, &l2cap_channels); 1901 while (btstack_linked_list_iterator_has_next(&it)){ 1902 1903 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 1904 1905 if (channel->channel_type != L2CAP_CHANNEL_TYPE_CLASSIC) continue; 1906 1907 // log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var); 1908 bool finalized = l2cap_run_for_classic_channel(channel); 1909 1910 if (!finalized) { 1911 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1912 l2cap_run_for_classic_channel_ertm(channel); 1913 #endif 1914 } 1915 } 1916 #endif 1917 1918 #ifdef ENABLE_LE_DATA_CHANNELS 1919 l2cap_run_le_data_channels(); 1920 #endif 1921 1922 #ifdef ENABLE_BLE 1923 // send l2cap con paramter update if necessary 1924 hci_connections_get_iterator(&it); 1925 while(btstack_linked_list_iterator_has_next(&it)){ 1926 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1927 if ((connection->address_type != BD_ADDR_TYPE_LE_PUBLIC) && (connection->address_type != BD_ADDR_TYPE_LE_RANDOM)) continue; 1928 if (!hci_can_send_acl_packet_now(connection->con_handle)) continue; 1929 switch (connection->le_con_parameter_update_state){ 1930 case CON_PARAMETER_UPDATE_SEND_REQUEST: 1931 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE; 1932 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_REQUEST, l2cap_next_sig_id(), 1933 connection->le_conn_interval_min, connection->le_conn_interval_max, connection->le_conn_latency, connection->le_supervision_timeout); 1934 break; 1935 case CON_PARAMETER_UPDATE_SEND_RESPONSE: 1936 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_CHANGE_HCI_CON_PARAMETERS; 1937 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 0); 1938 break; 1939 case CON_PARAMETER_UPDATE_DENY: 1940 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE; 1941 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 1); 1942 break; 1943 default: 1944 break; 1945 } 1946 } 1947 #endif 1948 1949 // log_info("l2cap_run: exit"); 1950 } 1951 1952 #ifdef ENABLE_CLASSIC 1953 static void l2cap_ready_to_connect(l2cap_channel_t * channel){ 1954 1955 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1956 // assumption: outgoing connection 1957 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 1958 if (connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_IDLE){ 1959 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 1960 channel->state = L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES; 1961 return; 1962 } 1963 #endif 1964 1965 // fine, go ahead 1966 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 1967 } 1968 1969 static void l2cap_handle_connection_complete(hci_con_handle_t con_handle, l2cap_channel_t * channel){ 1970 if ((channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE) || (channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION)) { 1971 log_info("connection complete con_handle %04x - for channel %p cid 0x%04x", (int) con_handle, channel, channel->local_cid); 1972 channel->con_handle = con_handle; 1973 // query remote features if pairing is required 1974 if (channel->required_security_level > LEVEL_0){ 1975 channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES; 1976 hci_remote_features_query(con_handle); 1977 } else { 1978 l2cap_ready_to_connect(channel); 1979 } 1980 } 1981 } 1982 1983 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){ 1984 if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return; 1985 // double check if all feature pages are complete 1986 1987 bool security_required = channel->required_security_level > LEVEL_0; 1988 1989 // abort if Secure Connections Only Mode with legacy connection 1990 if (security_required && gap_get_secure_connections_only_mode() && gap_secure_connection(channel->con_handle) == 0){ 1991 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY); 1992 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1993 l2cap_free_channel_entry(channel); 1994 return; 1995 } 1996 1997 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) != 0){ 1998 1999 // Core V5.2, Vol 3, Part C, 5.2.2.2 - Security Mode 4 2000 // When a remote device attempts to access a service offered by a Bluetooth device that is in security mode 4 2001 // and a sufficient link key exists and authentication has not been performed the local device shall authenticate 2002 // the remote device and enable encryption after the channel establishment request is received but before a channel 2003 // establishment confirmation (L2CAP_ConnectRsp with result code of 0x0000 or a higher-level channel establishment 2004 // confirmation such as that of RFCOMM) is sent. 2005 2006 // If the remote device has indicated support for Secure Simple Pairing, a channel establishment request is 2007 // received for a service other than SDP, and encryption has not yet been enabled, then the local device shall 2008 // disconnect the ACL link with error code 0x05 - Authentication Failure. 2009 2010 // => Disconnect if l2cap request received in mode 4 and ssp supported, non-sdp psm, not encrypted, no link key available 2011 if ((gap_get_security_mode() == GAP_SECURITY_MODE_4) 2012 && gap_ssp_supported_on_both_sides(channel->con_handle) 2013 && (channel->psm != PSM_SDP) 2014 && (gap_encryption_key_size(channel->con_handle) == 0) 2015 && (gap_bonded(channel->con_handle) == false)){ 2016 hci_disconnect_security_block(channel->con_handle); 2017 return; 2018 } 2019 2020 // incoming: assert security requirements 2021 channel->state = L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE; 2022 if (channel->required_security_level <= gap_security_level(channel->con_handle)){ 2023 l2cap_handle_security_level_incoming_sufficient(channel); 2024 } else { 2025 // send connection pending if not already done 2026 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONN_RESP_PEND) == 0){ 2027 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND; 2028 } 2029 gap_request_security_level(channel->con_handle, channel->required_security_level); 2030 } 2031 } else { 2032 // outgoing: we have been waiting for remote supported features 2033 if (security_required){ 2034 // request security level 2035 channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE; 2036 gap_request_security_level(channel->con_handle, channel->required_security_level); 2037 } else { 2038 l2cap_ready_to_connect(channel); 2039 } 2040 } 2041 } 2042 #endif 2043 2044 #ifdef L2CAP_USES_CHANNELS 2045 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, 2046 uint16_t psm, uint16_t local_mtu, gap_security_level_t security_level){ 2047 2048 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 2049 if (!channel) { 2050 return NULL; 2051 } 2052 2053 // fill in 2054 channel->packet_handler = packet_handler; 2055 channel->channel_type = channel_type; 2056 bd_addr_copy(channel->address, address); 2057 channel->address_type = address_type; 2058 channel->psm = psm; 2059 channel->local_mtu = local_mtu; 2060 channel->remote_mtu = L2CAP_DEFAULT_MTU; 2061 channel->required_security_level = security_level; 2062 2063 // 2064 channel->local_cid = l2cap_next_local_cid(); 2065 channel->con_handle = HCI_CON_HANDLE_INVALID; 2066 2067 // set initial state 2068 channel->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 2069 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 2070 channel->remote_sig_id = L2CAP_SIG_ID_INVALID; 2071 channel->local_sig_id = L2CAP_SIG_ID_INVALID; 2072 2073 log_info("create channel %p, local_cid 0x%04x", channel, channel->local_cid); 2074 2075 return channel; 2076 } 2077 2078 static void l2cap_free_channel_entry(l2cap_channel_t * channel){ 2079 log_info("free channel %p, local_cid 0x%04x", channel, channel->local_cid); 2080 // assert all timers are stopped 2081 l2cap_stop_rtx(channel); 2082 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2083 l2cap_ertm_stop_retransmission_timer(channel); 2084 l2cap_ertm_stop_monitor_timer(channel); 2085 #endif 2086 // free memory 2087 btstack_memory_l2cap_channel_free(channel); 2088 } 2089 #endif 2090 2091 #ifdef ENABLE_CLASSIC 2092 2093 /** 2094 * @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary. 2095 * @param packet_handler 2096 * @param address 2097 * @param psm 2098 * @param mtu 2099 * @param local_cid 2100 */ 2101 2102 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){ 2103 // limit MTU to the size of our outgoing HCI buffer 2104 uint16_t local_mtu = btstack_min(mtu, l2cap_max_mtu()); 2105 2106 // determine security level based on psm 2107 const gap_security_level_t security_level = l2cap_security_level_0_allowed_for_PSM(psm) ? LEVEL_0 : gap_get_security_level(); 2108 log_info("create channel addr %s psm 0x%x mtu %u -> local mtu %u, sec level %u", bd_addr_to_str(address), psm, mtu, local_mtu, (int) security_level); 2109 2110 l2cap_channel_t * channel = l2cap_create_channel_entry(channel_packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, address, BD_ADDR_TYPE_ACL, psm, local_mtu, security_level); 2111 if (!channel) { 2112 return BTSTACK_MEMORY_ALLOC_FAILED; 2113 } 2114 2115 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2116 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2117 #endif 2118 2119 // add to connections list 2120 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2121 2122 // store local_cid 2123 if (out_local_cid){ 2124 *out_local_cid = channel->local_cid; 2125 } 2126 2127 // state: L2CAP_STATE_WILL_SEND_CREATE_CONNECTION 2128 2129 // check if hci connection is already usable, 2130 hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_ACL); 2131 if (conn && conn->state == OPEN){ 2132 // simulate connection complete 2133 l2cap_handle_connection_complete(conn->con_handle, channel); 2134 2135 // state: L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES or L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST 2136 2137 // simulate if remote supported features if requested and already received 2138 if ((channel->state == L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) && hci_remote_features_available(conn->con_handle)) { 2139 // simulate remote features received 2140 l2cap_handle_remote_supported_features_received(channel); 2141 } 2142 } 2143 2144 l2cap_run(); 2145 2146 return ERROR_CODE_SUCCESS; 2147 } 2148 2149 void l2cap_disconnect(uint16_t local_cid, uint8_t reason){ 2150 log_info("disconnect local_cid 0x%x reason 0x%x", local_cid, reason); 2151 UNUSED(reason); 2152 // find channel for local_cid 2153 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 2154 if (channel) { 2155 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2156 } 2157 // process 2158 l2cap_run(); 2159 } 2160 2161 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 2162 // mark all channels before emitting open events as these could trigger new connetion requests to the same device 2163 btstack_linked_list_iterator_t it; 2164 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2165 while (btstack_linked_list_iterator_has_next(&it)){ 2166 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2167 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2168 if (bd_addr_cmp( channel->address, address) != 0) continue; 2169 // channel for this address found 2170 switch (channel->state){ 2171 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 2172 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 2173 channel->state = L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD; 2174 break; 2175 default: 2176 break; 2177 } 2178 } 2179 // emit and free marked entries. restart loop to deal with list changes 2180 int done = 0; 2181 while (!done) { 2182 done = 1; 2183 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2184 while (btstack_linked_list_iterator_has_next(&it)){ 2185 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2186 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2187 if (channel->state == L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD){ 2188 done = 0; 2189 // failure, forward error code 2190 l2cap_handle_channel_open_failed(channel, status); 2191 // discard channel 2192 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2193 l2cap_free_channel_entry(channel); 2194 break; 2195 } 2196 } 2197 } 2198 2199 } 2200 2201 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 2202 btstack_linked_list_iterator_t it; 2203 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2204 while (btstack_linked_list_iterator_has_next(&it)){ 2205 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2206 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2207 if ( ! bd_addr_cmp( channel->address, address) ){ 2208 l2cap_handle_connection_complete(handle, channel); 2209 } 2210 } 2211 // process 2212 l2cap_run(); 2213 } 2214 #endif 2215 2216 static bool l2cap_channel_ready_to_send(l2cap_channel_t * channel){ 2217 switch (channel->channel_type){ 2218 #ifdef ENABLE_CLASSIC 2219 case L2CAP_CHANNEL_TYPE_CLASSIC: 2220 if (channel->state != L2CAP_STATE_OPEN) return false; 2221 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2222 // send if we have more data and remote windows isn't full yet 2223 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) { 2224 if (channel->unacked_frames >= btstack_min(channel->num_stored_tx_frames, channel->remote_tx_window_size)) return false; 2225 return hci_can_send_acl_classic_packet_now() != 0; 2226 } 2227 #endif 2228 if (!channel->waiting_for_can_send_now) return false; 2229 return (hci_can_send_acl_classic_packet_now() != 0); 2230 case L2CAP_CHANNEL_TYPE_CONNECTIONLESS: 2231 if (!channel->waiting_for_can_send_now) return false; 2232 return hci_can_send_acl_classic_packet_now() != 0; 2233 #endif 2234 #ifdef ENABLE_BLE 2235 case L2CAP_CHANNEL_TYPE_FIXED: 2236 if (!channel->waiting_for_can_send_now) return false; 2237 return hci_can_send_acl_le_packet_now() != 0; 2238 #ifdef ENABLE_LE_DATA_CHANNELS 2239 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2240 if (channel->state != L2CAP_STATE_OPEN) return false; 2241 if (channel->send_sdu_buffer == NULL) return false; 2242 if (channel->credits_outgoing == 0u) return false; 2243 return hci_can_send_acl_le_packet_now() != 0; 2244 #endif 2245 #endif 2246 default: 2247 return false; 2248 } 2249 } 2250 2251 static void l2cap_channel_trigger_send(l2cap_channel_t * channel){ 2252 switch (channel->channel_type){ 2253 #ifdef ENABLE_CLASSIC 2254 case L2CAP_CHANNEL_TYPE_CLASSIC: 2255 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2256 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) { 2257 l2cap_ertm_channel_send_information_frame(channel); 2258 return; 2259 } 2260 #endif 2261 channel->waiting_for_can_send_now = 0; 2262 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2263 break; 2264 case L2CAP_CHANNEL_TYPE_CONNECTIONLESS: 2265 channel->waiting_for_can_send_now = 0; 2266 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2267 break; 2268 #endif 2269 #ifdef ENABLE_BLE 2270 case L2CAP_CHANNEL_TYPE_FIXED: 2271 channel->waiting_for_can_send_now = 0; 2272 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2273 break; 2274 #ifdef ENABLE_LE_DATA_CHANNELS 2275 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2276 l2cap_le_send_pdu(channel); 2277 break; 2278 #endif 2279 #endif 2280 default: 2281 break; 2282 } 2283 } 2284 2285 static void l2cap_notify_channel_can_send(void){ 2286 bool done = false; 2287 while (!done){ 2288 done = true; 2289 btstack_linked_list_iterator_t it; 2290 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2291 while (btstack_linked_list_iterator_has_next(&it)){ 2292 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2293 bool ready = l2cap_channel_ready_to_send(channel); 2294 if (!ready) continue; 2295 2296 // requeue channel for fairness 2297 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2298 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2299 2300 // trigger sending 2301 l2cap_channel_trigger_send(channel); 2302 2303 // exit inner loop as we just broke the iterator, but try again 2304 done = false; 2305 break; 2306 } 2307 } 2308 } 2309 2310 #ifdef L2CAP_USES_CHANNELS 2311 2312 static int l2cap_send_open_failed_on_hci_disconnect(l2cap_channel_t * channel){ 2313 // open cannot fail for for incoming connections 2314 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) return 0; 2315 2316 // check state 2317 switch (channel->state){ 2318 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 2319 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 2320 case L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES: 2321 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 2322 case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT: 2323 case L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES: 2324 case L2CAP_STATE_WAIT_CONNECT_RSP: 2325 case L2CAP_STATE_CONFIG: 2326 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 2327 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST: 2328 case L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE: 2329 case L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD: 2330 return 1; 2331 2332 case L2CAP_STATE_OPEN: 2333 case L2CAP_STATE_CLOSED: 2334 case L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES: 2335 case L2CAP_STATE_WAIT_DISCONNECT: 2336 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_INSUFFICIENT_SECURITY: 2337 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 2338 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 2339 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 2340 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 2341 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE: 2342 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT: 2343 case L2CAP_STATE_INVALID: 2344 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 2345 return 0; 2346 2347 default: 2348 // get a "warning" about new states 2349 btstack_assert(false); 2350 return 0; 2351 } 2352 } 2353 #endif 2354 2355 #ifdef ENABLE_CLASSIC 2356 static void l2cap_handle_hci_disconnect_event(l2cap_channel_t * channel){ 2357 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 2358 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 2359 } else { 2360 l2cap_handle_channel_closed(channel); 2361 } 2362 l2cap_free_channel_entry(channel); 2363 } 2364 #endif 2365 2366 #ifdef ENABLE_LE_DATA_CHANNELS 2367 static void l2cap_handle_hci_le_disconnect_event(l2cap_channel_t * channel){ 2368 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 2369 l2cap_emit_le_channel_opened(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 2370 } else { 2371 l2cap_emit_le_channel_closed(channel); 2372 } 2373 l2cap_free_channel_entry(channel); 2374 } 2375 #endif 2376 2377 #ifdef ENABLE_CLASSIC 2378 static void l2cap_check_classic_timeout(hci_con_handle_t handle){ 2379 if (gap_get_connection_type(handle) != GAP_CONNECTION_ACL) { 2380 return; 2381 } 2382 if (hci_authentication_active_for_handle(handle)) { 2383 return; 2384 } 2385 bool hci_con_used = false; 2386 btstack_linked_list_iterator_t it; 2387 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2388 while (btstack_linked_list_iterator_has_next(&it)){ 2389 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2390 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2391 if (channel->con_handle != handle) continue; 2392 hci_con_used = true; 2393 break; 2394 } 2395 if (hci_con_used) { 2396 return; 2397 } 2398 if (!hci_can_send_command_packet_now()) { 2399 return; 2400 } 2401 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 2402 } 2403 2404 static void l2cap_handle_features_complete(hci_con_handle_t handle){ 2405 if (hci_remote_features_available(handle) == false){ 2406 return; 2407 } 2408 btstack_linked_list_iterator_t it; 2409 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2410 while (btstack_linked_list_iterator_has_next(&it)){ 2411 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2412 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2413 if (channel->con_handle != handle) continue; 2414 log_info("remote supported features, channel %p, cid %04x - state %u", channel, channel->local_cid, channel->state); 2415 l2cap_handle_remote_supported_features_received(channel); 2416 } 2417 } 2418 2419 static void l2cap_handle_security_level_incoming_sufficient(l2cap_channel_t * channel){ 2420 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2421 // we need to know if ERTM is supported before sending a config response 2422 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 2423 if (connection->l2cap_state.information_state != L2CAP_INFORMATION_STATE_DONE){ 2424 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 2425 channel->state = L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES; 2426 return; 2427 } 2428 #endif 2429 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 2430 l2cap_emit_incoming_connection(channel); 2431 } 2432 2433 static void l2cap_handle_security_level(hci_con_handle_t handle, gap_security_level_t actual_level){ 2434 log_info("security level update for handle 0x%04x", handle); 2435 btstack_linked_list_iterator_t it; 2436 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2437 while (btstack_linked_list_iterator_has_next(&it)){ 2438 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2439 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2440 if (channel->con_handle != handle) continue; 2441 2442 gap_security_level_t required_level = channel->required_security_level; 2443 2444 log_info("channel %p, cid %04x - state %u: actual %u >= required %u?", channel, channel->local_cid, channel->state, actual_level, required_level); 2445 2446 switch (channel->state){ 2447 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 2448 if (actual_level >= required_level){ 2449 l2cap_handle_security_level_incoming_sufficient(channel); 2450 } else { 2451 channel->reason = 0x0003; // security block 2452 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2453 } 2454 break; 2455 2456 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 2457 if (actual_level >= required_level){ 2458 l2cap_ready_to_connect(channel); 2459 } else { 2460 // security level insufficient, report error and free channel 2461 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY); 2462 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2463 l2cap_free_channel_entry(channel); 2464 } 2465 break; 2466 2467 default: 2468 break; 2469 } 2470 } 2471 } 2472 #endif 2473 2474 #ifdef L2CAP_USES_CHANNELS 2475 static void l2cap_handle_disconnection_complete(hci_con_handle_t handle){ 2476 // collect channels to close 2477 btstack_linked_list_t channels_to_close = NULL; 2478 btstack_linked_list_iterator_t it; 2479 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2480 while (btstack_linked_list_iterator_has_next(&it)) { 2481 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2482 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2483 if (channel->con_handle != handle) continue; 2484 btstack_linked_list_iterator_remove(&it); 2485 btstack_linked_list_add(&channels_to_close, (btstack_linked_item_t *) channel); 2486 } 2487 // send l2cap open failed or closed events for all channels on this handle and free them 2488 btstack_linked_list_iterator_init(&it, &channels_to_close); 2489 while (btstack_linked_list_iterator_has_next(&it)) { 2490 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2491 btstack_linked_list_iterator_remove(&it); 2492 switch(channel->channel_type){ 2493 #ifdef ENABLE_CLASSIC 2494 case L2CAP_CHANNEL_TYPE_CLASSIC: 2495 l2cap_handle_hci_disconnect_event(channel); 2496 break; 2497 #endif 2498 #ifdef ENABLE_LE_DATA_CHANNELS 2499 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2500 l2cap_handle_hci_le_disconnect_event(channel); 2501 break; 2502 #endif 2503 default: 2504 break; 2505 } 2506 } 2507 } 2508 #endif 2509 2510 static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t cid, uint8_t *packet, uint16_t size){ 2511 2512 UNUSED(packet_type); // ok: registered with hci_event_callback_registration 2513 UNUSED(cid); // ok: there is no channel 2514 UNUSED(size); // ok: fixed format events read from HCI buffer 2515 2516 #ifdef ENABLE_CLASSIC 2517 bd_addr_t address; 2518 gap_security_level_t security_level; 2519 #endif 2520 #ifdef L2CAP_USES_CHANNELS 2521 hci_con_handle_t handle; 2522 #endif 2523 2524 switch(hci_event_packet_get_type(packet)){ 2525 2526 // Notify channel packet handler if they can send now 2527 case HCI_EVENT_TRANSPORT_PACKET_SENT: 2528 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 2529 case BTSTACK_EVENT_NR_CONNECTIONS_CHANGED: 2530 l2cap_run(); // try sending signaling packets first 2531 l2cap_notify_channel_can_send(); 2532 break; 2533 2534 case HCI_EVENT_COMMAND_STATUS: 2535 #ifdef ENABLE_CLASSIC 2536 // check command status for create connection for errors 2537 if (HCI_EVENT_IS_COMMAND_STATUS(packet, hci_create_connection)){ 2538 // cache outgoing address and reset 2539 (void)memcpy(address, l2cap_outgoing_classic_addr, 6); 2540 memset(l2cap_outgoing_classic_addr, 0, 6); 2541 // error => outgoing connection failed 2542 uint8_t status = hci_event_command_status_get_status(packet); 2543 if (status){ 2544 l2cap_handle_connection_failed_for_addr(address, status); 2545 } 2546 } 2547 #endif 2548 l2cap_run(); // try sending signaling packets first 2549 break; 2550 2551 #ifdef ENABLE_CLASSIC 2552 // handle connection complete events 2553 case HCI_EVENT_CONNECTION_COMPLETE: 2554 reverse_bd_addr(&packet[5], address); 2555 if (packet[2] == 0){ 2556 handle = little_endian_read_16(packet, 3); 2557 l2cap_handle_connection_success_for_addr(address, handle); 2558 } else { 2559 l2cap_handle_connection_failed_for_addr(address, packet[2]); 2560 } 2561 break; 2562 2563 // handle successful create connection cancel command 2564 case HCI_EVENT_COMMAND_COMPLETE: 2565 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_create_connection_cancel)) { 2566 if (packet[5] == 0){ 2567 reverse_bd_addr(&packet[6], address); 2568 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 2569 l2cap_handle_connection_failed_for_addr(address, 0x16); 2570 } 2571 } 2572 l2cap_run(); // try sending signaling packets first 2573 break; 2574 #endif 2575 2576 #ifdef L2CAP_USES_CHANNELS 2577 // handle disconnection complete events 2578 case HCI_EVENT_DISCONNECTION_COMPLETE: 2579 handle = little_endian_read_16(packet, 3); 2580 l2cap_handle_disconnection_complete(handle); 2581 break; 2582 #endif 2583 2584 // HCI Connection Timeouts 2585 #ifdef ENABLE_CLASSIC 2586 case L2CAP_EVENT_TIMEOUT_CHECK: 2587 handle = little_endian_read_16(packet, 2); 2588 l2cap_check_classic_timeout(handle); 2589 break; 2590 2591 case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE: 2592 case HCI_EVENT_READ_REMOTE_EXTENDED_FEATURES_COMPLETE: 2593 handle = little_endian_read_16(packet, 3); 2594 l2cap_handle_features_complete(handle); 2595 break; 2596 2597 case GAP_EVENT_SECURITY_LEVEL: 2598 handle = little_endian_read_16(packet, 2); 2599 security_level = (gap_security_level_t) packet[4]; 2600 l2cap_handle_security_level(handle, security_level); 2601 break; 2602 #endif 2603 default: 2604 break; 2605 } 2606 2607 l2cap_run(); 2608 } 2609 2610 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t cid, uint16_t data){ 2611 // Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused." 2612 if (l2cap_signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 2613 l2cap_signaling_responses[l2cap_signaling_responses_pending].handle = handle; 2614 l2cap_signaling_responses[l2cap_signaling_responses_pending].code = code; 2615 l2cap_signaling_responses[l2cap_signaling_responses_pending].sig_id = sig_id; 2616 l2cap_signaling_responses[l2cap_signaling_responses_pending].cid = cid; 2617 l2cap_signaling_responses[l2cap_signaling_responses_pending].data = data; 2618 l2cap_signaling_responses_pending++; 2619 l2cap_run(); 2620 } 2621 } 2622 2623 #ifdef ENABLE_CLASSIC 2624 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 2625 switch (channel->state){ 2626 case L2CAP_STATE_CONFIG: 2627 case L2CAP_STATE_OPEN: 2628 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 2629 case L2CAP_STATE_WAIT_DISCONNECT: 2630 break; 2631 default: 2632 // ignore in other states 2633 return; 2634 } 2635 2636 channel->remote_sig_id = identifier; 2637 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 2638 l2cap_run(); 2639 } 2640 2641 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 2642 2643 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid); 2644 l2cap_service_t *service = l2cap_get_service(psm); 2645 if (!service) { 2646 // 0x0002 PSM not supported 2647 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 2648 return; 2649 } 2650 2651 hci_connection_t * hci_connection = hci_connection_for_handle( handle ); 2652 if (!hci_connection) { 2653 // 2654 log_error("no hci_connection for handle %u", handle); 2655 return; 2656 } 2657 2658 // alloc structure 2659 gap_security_level_t required_level = service->required_security_level; 2660 if (gap_get_secure_connections_only_mode() && (required_level != LEVEL_0)){ 2661 required_level = LEVEL_4; 2662 } 2663 l2cap_channel_t * channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, hci_connection->address, BD_ADDR_TYPE_ACL, 2664 psm, service->mtu, required_level); 2665 if (!channel){ 2666 // 0x0004 No resources available 2667 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 2668 return; 2669 } 2670 2671 channel->con_handle = handle; 2672 channel->remote_cid = source_cid; 2673 channel->remote_sig_id = sig_id; 2674 2675 // limit local mtu to max acl packet length - l2cap header 2676 if (channel->local_mtu > l2cap_max_mtu()) { 2677 channel->local_mtu = l2cap_max_mtu(); 2678 } 2679 2680 // set initial state 2681 channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES; 2682 channel->state_var = L2CAP_CHANNEL_STATE_VAR_INCOMING; 2683 2684 // add to connections list 2685 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2686 2687 // send conn resp pending if remote supported features have not been received yet 2688 if (hci_remote_features_available(handle)) { 2689 l2cap_handle_remote_supported_features_received(channel); 2690 } else { 2691 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND; 2692 hci_remote_features_query(handle); 2693 } 2694 } 2695 2696 void l2cap_accept_connection(uint16_t local_cid){ 2697 log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid); 2698 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 2699 if (!channel) { 2700 log_error("accept called but local_cid 0x%x not found", local_cid); 2701 return; 2702 } 2703 2704 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2705 // configure L2CAP Basic mode 2706 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2707 #endif 2708 2709 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 2710 2711 // process 2712 l2cap_run(); 2713 } 2714 2715 void l2cap_decline_connection(uint16_t local_cid){ 2716 log_info("decline local_cid 0x%x", local_cid); 2717 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 2718 if (!channel) { 2719 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 2720 return; 2721 } 2722 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2723 channel->reason = 0x04; // no resources available 2724 l2cap_run(); 2725 } 2726 2727 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2728 static void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 2729 2730 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2731 uint8_t use_fcs = 1; 2732 #endif 2733 2734 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2735 2736 uint16_t flags = little_endian_read_16(command, 6); 2737 if (flags & 1) { 2738 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT); 2739 } 2740 2741 // accept the other's configuration options 2742 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2743 uint16_t pos = 8; 2744 while (pos < end_pos){ 2745 uint8_t option_hint = command[pos] >> 7; 2746 uint8_t option_type = command[pos] & 0x7f; 2747 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2748 pos++; 2749 uint8_t length = command[pos++]; 2750 // MTU { type(8): 1, len(8):2, MTU(16) } 2751 if ((option_type == L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT) && (length == 2)){ 2752 channel->remote_mtu = little_endian_read_16(command, pos); 2753 log_info("Remote MTU %u", channel->remote_mtu); 2754 if (channel->remote_mtu > l2cap_max_mtu()){ 2755 log_info("Remote MTU %u larger than outgoing buffer, only using MTU = %u", channel->remote_mtu, l2cap_max_mtu()); 2756 channel->remote_mtu = l2cap_max_mtu(); 2757 } 2758 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 2759 } 2760 // Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)} 2761 if ((option_type == L2CAP_CONFIG_OPTION_TYPE_FLUSH_TIMEOUT) && (length == 2)){ 2762 channel->flush_timeout = little_endian_read_16(command, pos); 2763 log_info("Flush timeout: %u ms", channel->flush_timeout); 2764 } 2765 2766 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2767 // Retransmission and Flow Control Option 2768 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2769 l2cap_channel_mode_t mode = (l2cap_channel_mode_t) command[pos]; 2770 switch(channel->mode){ 2771 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2772 // Store remote config 2773 channel->remote_tx_window_size = command[pos+1]; 2774 channel->remote_max_transmit = command[pos+2]; 2775 channel->remote_retransmission_timeout_ms = little_endian_read_16(command, pos + 3); 2776 channel->remote_monitor_timeout_ms = little_endian_read_16(command, pos + 5); 2777 channel->remote_mps = little_endian_read_16(command, pos + 7); 2778 log_info("FC&C config: tx window: %u, max transmit %u, retrans timeout %u, monitor timeout %u, mps %u", 2779 channel->remote_tx_window_size, 2780 channel->remote_max_transmit, 2781 channel->remote_retransmission_timeout_ms, 2782 channel->remote_monitor_timeout_ms, 2783 channel->remote_mps); 2784 // If ERTM mandatory, but remote doens't offer ERTM -> disconnect 2785 if (channel->ertm_mandatory && mode != L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 2786 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2787 } else { 2788 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM); 2789 } 2790 break; 2791 case L2CAP_CHANNEL_MODE_BASIC: 2792 switch (mode){ 2793 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2794 // remote asks for ERTM, but we want basic mode. disconnect if this happens a second time 2795 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED){ 2796 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2797 } 2798 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED); 2799 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED); 2800 break; 2801 default: // case L2CAP_CHANNEL_MODE_BASIC: 2802 // TODO store and evaluate configuration 2803 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM); 2804 break; 2805 } 2806 break; 2807 default: 2808 break; 2809 } 2810 } 2811 if (option_type == L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE && length == 1){ 2812 use_fcs = command[pos]; 2813 } 2814 #endif 2815 // check for unknown options 2816 if ((option_hint == 0) && ((option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT) || (option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE))){ 2817 log_info("l2cap cid %u, unknown option 0x%02x", channel->local_cid, option_type); 2818 channel->unknown_option = option_type; 2819 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2820 } 2821 pos += length; 2822 } 2823 2824 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2825 // "FCS" has precedence over "No FCS" 2826 uint8_t update = channel->fcs_option || use_fcs; 2827 log_info("local fcs: %u, remote fcs: %u -> %u", channel->fcs_option, use_fcs, update); 2828 channel->fcs_option = update; 2829 // If ERTM mandatory, but remote didn't send Retransmission and Flowcontrol options -> disconnect 2830 if (((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM) == 0) & (channel->ertm_mandatory)){ 2831 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2832 } 2833 #endif 2834 } 2835 2836 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2837 static void l2cap_signaling_handle_configure_response(l2cap_channel_t *channel, uint8_t result, uint8_t *command){ 2838 log_info("l2cap_signaling_handle_configure_response"); 2839 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2840 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2841 uint16_t pos = 10; 2842 while (pos < end_pos){ 2843 uint8_t option_hint = command[pos] >> 7; 2844 uint8_t option_type = command[pos] & 0x7f; 2845 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2846 pos++; 2847 uint8_t length = command[pos++]; 2848 2849 // Retransmission and Flow Control Option 2850 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2851 switch (channel->mode){ 2852 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2853 if (channel->ertm_mandatory){ 2854 // ?? 2855 } else { 2856 // On 'Reject - Unacceptable Parameters' to our optional ERTM request, fall back to BASIC mode 2857 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2858 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 2859 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2860 } 2861 } 2862 break; 2863 case L2CAP_CHANNEL_MODE_BASIC: 2864 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2865 // On 'Reject - Unacceptable Parameters' to our Basic mode request, disconnect 2866 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2867 } 2868 break; 2869 default: 2870 break; 2871 } 2872 } 2873 2874 // check for unknown options 2875 if (option_hint == 0 && (option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT || option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE)){ 2876 log_info("l2cap cid %u, unknown option 0x%02x", channel->local_cid, option_type); 2877 channel->unknown_option = option_type; 2878 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2879 } 2880 2881 pos += length; 2882 } 2883 #else 2884 UNUSED(channel); // ok: no code 2885 UNUSED(result); // ok: no code 2886 UNUSED(command); // ok: no code 2887 #endif 2888 } 2889 2890 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 2891 // log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var); 2892 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 2893 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 2894 // addition check that fixes re-entrance issue causing l2cap event channel opened twice 2895 if (channel->state == L2CAP_STATE_OPEN) return 0; 2896 return 1; 2897 } 2898 2899 2900 // @pre command len is valid, see check in l2cap_signaling_handler_dispatch 2901 static void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 2902 2903 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 2904 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2905 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2906 uint16_t result = 0; 2907 2908 log_info("L2CAP signaling handler code %u, state %u", code, channel->state); 2909 2910 // handle DISCONNECT REQUESTS seperately 2911 if (code == DISCONNECTION_REQUEST){ 2912 l2cap_handle_disconnect_request(channel, identifier); 2913 return; 2914 } 2915 2916 // @STATEMACHINE(l2cap) 2917 switch (channel->state) { 2918 2919 case L2CAP_STATE_WAIT_CONNECT_RSP: 2920 switch (code){ 2921 case CONNECTION_RESPONSE: 2922 if (cmd_len < 8){ 2923 // command imcomplete 2924 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2925 break; 2926 } 2927 l2cap_stop_rtx(channel); 2928 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2929 switch (result) { 2930 case 0: 2931 // successful connection 2932 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2933 channel->state = L2CAP_STATE_CONFIG; 2934 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 2935 break; 2936 case 1: 2937 // connection pending. get some coffee, but start the ERTX 2938 l2cap_start_ertx(channel); 2939 break; 2940 default: 2941 // channel closed 2942 channel->state = L2CAP_STATE_CLOSED; 2943 // map l2cap connection response result to BTstack status enumeration 2944 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 2945 2946 // drop link key if security block 2947 if ((L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result) == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 2948 gap_drop_link_key_for_bd_addr(channel->address); 2949 } 2950 2951 // discard channel 2952 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2953 l2cap_free_channel_entry(channel); 2954 break; 2955 } 2956 break; 2957 2958 default: 2959 //@TODO: implement other signaling packets 2960 break; 2961 } 2962 break; 2963 2964 case L2CAP_STATE_CONFIG: 2965 switch (code) { 2966 case CONFIGURE_REQUEST: 2967 if (cmd_len < 4){ 2968 // command incomplete 2969 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2970 break; 2971 } 2972 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 2973 l2cap_signaling_handle_configure_request(channel, command); 2974 if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){ 2975 // only done if continuation not set 2976 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ); 2977 } 2978 break; 2979 case CONFIGURE_RESPONSE: 2980 if (cmd_len < 6){ 2981 // command incomplete 2982 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2983 break; 2984 } 2985 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2986 l2cap_stop_rtx(channel); 2987 l2cap_signaling_handle_configure_response(channel, result, command); 2988 switch (result){ 2989 case 0: // success 2990 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP); 2991 break; 2992 case 4: // pending 2993 l2cap_start_ertx(channel); 2994 break; 2995 default: 2996 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2997 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION && channel->ertm_mandatory){ 2998 // remote does not offer ertm but it's required 2999 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3000 break; 3001 } 3002 #endif 3003 // retry on negative result 3004 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 3005 break; 3006 } 3007 break; 3008 default: 3009 break; 3010 } 3011 if (l2cap_channel_ready_for_open(channel)){ 3012 3013 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3014 // assert that packet can be stored in fragment buffers in ertm 3015 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 3016 uint16_t effective_mps = btstack_min(channel->remote_mps, channel->local_mps); 3017 uint16_t usable_mtu = channel->num_tx_buffers == 1 ? effective_mps : channel->num_tx_buffers * effective_mps - 2; 3018 if (usable_mtu < channel->remote_mtu){ 3019 log_info("Remote MTU %u > max storable ERTM packet, only using MTU = %u", channel->remote_mtu, usable_mtu); 3020 channel->remote_mtu = usable_mtu; 3021 } 3022 } 3023 #endif 3024 // for open: 3025 channel->state = L2CAP_STATE_OPEN; 3026 l2cap_emit_channel_opened(channel, 0); 3027 } 3028 break; 3029 3030 case L2CAP_STATE_WAIT_DISCONNECT: 3031 switch (code) { 3032 case DISCONNECTION_RESPONSE: 3033 l2cap_finialize_channel_close(channel); 3034 break; 3035 default: 3036 //@TODO: implement other signaling packets 3037 break; 3038 } 3039 break; 3040 3041 case L2CAP_STATE_CLOSED: 3042 // @TODO handle incoming requests 3043 break; 3044 3045 case L2CAP_STATE_OPEN: 3046 //@TODO: implement other signaling packets, e.g. re-configure 3047 break; 3048 default: 3049 break; 3050 } 3051 // log_info("new state %u", channel->state); 3052 } 3053 3054 3055 // @pre command len is valid, see check in l2cap_acl_classic_handler 3056 static void l2cap_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command){ 3057 3058 btstack_linked_list_iterator_t it; 3059 3060 // get code, signalind identifier and command len 3061 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 3062 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 3063 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3064 3065 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_RESPONSE 3066 if ((code < 1) || (code == ECHO_RESPONSE) || (code > INFORMATION_RESPONSE)){ 3067 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3068 return; 3069 } 3070 3071 // general commands without an assigned channel 3072 switch(code) { 3073 3074 case CONNECTION_REQUEST: 3075 if (cmd_len == 4){ 3076 uint16_t psm = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3077 uint16_t source_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3078 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 3079 } else { 3080 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3081 } 3082 return; 3083 3084 case ECHO_REQUEST: 3085 l2cap_register_signaling_response(handle, code, sig_id, 0, 0); 3086 return; 3087 3088 case INFORMATION_REQUEST: 3089 if (cmd_len == 2) { 3090 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3091 l2cap_register_signaling_response(handle, code, sig_id, 0, info_type); 3092 } else { 3093 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3094 } 3095 return; 3096 3097 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3098 case INFORMATION_RESPONSE: { 3099 hci_connection_t * connection = hci_connection_for_handle(handle); 3100 if (!connection) return; 3101 if (connection->l2cap_state.information_state != L2CAP_INFORMATION_STATE_W4_EXTENDED_FEATURE_RESPONSE) return; 3102 3103 // get extended features from response if valid 3104 connection->l2cap_state.extended_feature_mask = 0; 3105 if (cmd_len >= 6) { 3106 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3107 uint16_t result = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3108 if (result == 0 && info_type == L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED) { 3109 connection->l2cap_state.extended_feature_mask = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 3110 } 3111 } 3112 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_DONE; 3113 log_info("extended features mask 0x%02x", connection->l2cap_state.extended_feature_mask); 3114 3115 // trigger connection request 3116 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3117 while (btstack_linked_list_iterator_has_next(&it)){ 3118 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3119 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 3120 if (channel->con_handle != handle) continue; 3121 3122 // incoming connection: ask user for channel configuration, esp. if ertm will be mandatory 3123 if (channel->state == L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES){ 3124 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 3125 l2cap_emit_incoming_connection(channel); 3126 continue; 3127 } 3128 3129 // outgoing connection 3130 if (channel->state == L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES){ 3131 3132 // if ERTM was requested, but is not listed in extended feature mask: 3133 if ((channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) && ((connection->l2cap_state.extended_feature_mask & 0x08) == 0)){ 3134 3135 if (channel->ertm_mandatory){ 3136 // bail if ERTM is mandatory 3137 channel->state = L2CAP_STATE_CLOSED; 3138 // map l2cap connection response result to BTstack status enumeration 3139 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_ERTM_NOT_SUPPORTED); 3140 // discard channel 3141 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3142 l2cap_free_channel_entry(channel); 3143 continue; 3144 3145 } else { 3146 // fallback to Basic mode 3147 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 3148 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 3149 } 3150 } 3151 3152 // respond to connection request 3153 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 3154 continue; 3155 } 3156 } 3157 return; 3158 } 3159 #endif 3160 3161 default: 3162 break; 3163 } 3164 3165 // Get potential destination CID 3166 uint16_t dest_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3167 3168 // Find channel for this sig_id and connection handle 3169 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3170 while (btstack_linked_list_iterator_has_next(&it)){ 3171 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3172 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 3173 if (channel->con_handle != handle) continue; 3174 if (code & 1) { 3175 // match odd commands (responses) by previous signaling identifier 3176 if (channel->local_sig_id == sig_id) { 3177 l2cap_signaling_handler_channel(channel, command); 3178 break; 3179 } 3180 } else { 3181 // match even commands (requests) by local channel id 3182 if (channel->local_cid == dest_cid) { 3183 l2cap_signaling_handler_channel(channel, command); 3184 break; 3185 } 3186 } 3187 } 3188 } 3189 #endif 3190 3191 #ifdef ENABLE_BLE 3192 3193 static void l2cap_emit_connection_parameter_update_response(hci_con_handle_t con_handle, uint16_t result){ 3194 uint8_t event[6]; 3195 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE; 3196 event[1] = 4; 3197 little_endian_store_16(event, 2, con_handle); 3198 little_endian_store_16(event, 4, result); 3199 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3200 if (!l2cap_event_packet_handler) return; 3201 (*l2cap_event_packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event)); 3202 } 3203 3204 // @returns valid 3205 static int l2cap_le_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command, uint8_t sig_id){ 3206 hci_connection_t * connection; 3207 uint16_t result; 3208 uint8_t event[12]; 3209 3210 #ifdef ENABLE_LE_DATA_CHANNELS 3211 btstack_linked_list_iterator_t it; 3212 l2cap_channel_t * channel; 3213 uint16_t local_cid; 3214 uint16_t le_psm; 3215 uint16_t new_credits; 3216 uint16_t credits_before; 3217 l2cap_service_t * service; 3218 uint16_t source_cid; 3219 #endif 3220 3221 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 3222 uint16_t len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3223 log_info("le dispatch: command 0x%02x, sig id %u, len %u", code, sig_id, len); 3224 3225 switch (code){ 3226 3227 case CONNECTION_PARAMETER_UPDATE_REQUEST: 3228 // check size 3229 if (len < 8u) return 0u; 3230 connection = hci_connection_for_handle(handle); 3231 if (connection != NULL){ 3232 if (connection->role != HCI_ROLE_MASTER){ 3233 // reject command without notifying upper layer when not in master role 3234 return 0; 3235 } 3236 le_connection_parameter_range_t existing_range; 3237 gap_get_connection_parameter_range(&existing_range); 3238 uint16_t le_conn_interval_min = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3239 uint16_t le_conn_interval_max = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3240 uint16_t le_conn_latency = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 3241 uint16_t le_supervision_timeout = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+6); 3242 3243 int update_parameter = gap_connection_parameter_range_included(&existing_range, le_conn_interval_min, le_conn_interval_max, le_conn_latency, le_supervision_timeout); 3244 if (update_parameter){ 3245 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE; 3246 connection->le_conn_interval_min = le_conn_interval_min; 3247 connection->le_conn_interval_max = le_conn_interval_max; 3248 connection->le_conn_latency = le_conn_latency; 3249 connection->le_supervision_timeout = le_supervision_timeout; 3250 } else { 3251 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY; 3252 } 3253 connection->le_con_param_update_identifier = sig_id; 3254 } 3255 3256 if (!l2cap_event_packet_handler) break; 3257 3258 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST; 3259 event[1] = 8; 3260 little_endian_store_16(event, 2, handle); 3261 (void)memcpy(&event[4], &command[4], 8); 3262 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3263 (*l2cap_event_packet_handler)( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3264 break; 3265 3266 case CONNECTION_PARAMETER_UPDATE_RESPONSE: 3267 // check size 3268 if (len < 2u) return 0u; 3269 result = little_endian_read_16(command, 4); 3270 l2cap_emit_connection_parameter_update_response(handle, result); 3271 break; 3272 3273 #ifdef ENABLE_LE_DATA_CHANNELS 3274 3275 case COMMAND_REJECT: 3276 // Find channel for this sig_id and connection handle 3277 channel = NULL; 3278 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3279 while (btstack_linked_list_iterator_has_next(&it)){ 3280 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3281 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3282 if (a_channel->con_handle != handle) continue; 3283 if (a_channel->local_sig_id != sig_id) continue; 3284 channel = a_channel; 3285 break; 3286 } 3287 if (!channel) break; 3288 3289 // if received while waiting for le connection response, assume legacy device 3290 if (channel->state == L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE){ 3291 channel->state = L2CAP_STATE_CLOSED; 3292 // no official value for this, use: Connection refused – LE_PSM not supported - 0x0002 3293 l2cap_emit_le_channel_opened(channel, 0x0002); 3294 3295 // discard channel 3296 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3297 l2cap_free_channel_entry(channel); 3298 break; 3299 } 3300 break; 3301 3302 case LE_CREDIT_BASED_CONNECTION_REQUEST: 3303 // check size 3304 if (len < 10u) return 0u; 3305 3306 // get hci connection, bail if not found (must not happen) 3307 connection = hci_connection_for_handle(handle); 3308 if (!connection) return 0; 3309 3310 // check if service registered 3311 le_psm = little_endian_read_16(command, 4); 3312 service = l2cap_le_get_service(le_psm); 3313 source_cid = little_endian_read_16(command, 6); 3314 3315 if (service){ 3316 if (source_cid < 0x40u){ 3317 // 0x0009 Connection refused - Invalid Source CID 3318 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0009); 3319 return 1; 3320 } 3321 3322 // go through list of channels for this ACL connection and check if we get a match 3323 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3324 while (btstack_linked_list_iterator_has_next(&it)){ 3325 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3326 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3327 if (a_channel->con_handle != handle) continue; 3328 if (a_channel->remote_cid != source_cid) continue; 3329 // 0x000a Connection refused - Source CID already allocated 3330 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x000a); 3331 return 1; 3332 } 3333 3334 // security: check encryption 3335 if (service->required_security_level >= LEVEL_2){ 3336 if (gap_encryption_key_size(handle) == 0){ 3337 // 0x0008 Connection refused - insufficient encryption 3338 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0008); 3339 return 1; 3340 } 3341 // anything less than 16 byte key size is insufficient 3342 if (gap_encryption_key_size(handle) < 16){ 3343 // 0x0007 Connection refused – insufficient encryption key size 3344 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0007); 3345 return 1; 3346 } 3347 } 3348 3349 // security: check authencation 3350 if (service->required_security_level >= LEVEL_3){ 3351 if (!gap_authenticated(handle)){ 3352 // 0x0005 Connection refused – insufficient authentication 3353 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0005); 3354 return 1; 3355 } 3356 } 3357 3358 // security: check authorization 3359 if (service->required_security_level >= LEVEL_4){ 3360 if (gap_authorization_state(handle) != AUTHORIZATION_GRANTED){ 3361 // 0x0006 Connection refused – insufficient authorization 3362 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0006); 3363 return 1; 3364 } 3365 } 3366 3367 // allocate channel 3368 channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL, connection->address, 3369 BD_ADDR_TYPE_LE_RANDOM, le_psm, service->mtu, service->required_security_level); 3370 if (!channel){ 3371 // 0x0004 Connection refused – no resources available 3372 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 3373 return 1; 3374 } 3375 3376 channel->con_handle = handle; 3377 channel->remote_cid = source_cid; 3378 channel->remote_sig_id = sig_id; 3379 channel->remote_mtu = little_endian_read_16(command, 8); 3380 channel->remote_mps = little_endian_read_16(command, 10); 3381 channel->credits_outgoing = little_endian_read_16(command, 12); 3382 3383 // set initial state 3384 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 3385 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_INCOMING; 3386 3387 // add to connections list 3388 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 3389 3390 // post connection request event 3391 l2cap_emit_le_incoming_connection(channel); 3392 3393 } else { 3394 // Connection refused – LE_PSM not supported 3395 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 3396 } 3397 break; 3398 3399 case LE_CREDIT_BASED_CONNECTION_RESPONSE: 3400 // check size 3401 if (len < 10u) return 0u; 3402 3403 // Find channel for this sig_id and connection handle 3404 channel = NULL; 3405 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3406 while (btstack_linked_list_iterator_has_next(&it)){ 3407 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3408 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3409 if (a_channel->con_handle != handle) continue; 3410 if (a_channel->local_sig_id != sig_id) continue; 3411 channel = a_channel; 3412 break; 3413 } 3414 if (!channel) break; 3415 3416 // cid + 0 3417 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+8); 3418 if (result){ 3419 channel->state = L2CAP_STATE_CLOSED; 3420 // map l2cap connection response result to BTstack status enumeration 3421 l2cap_emit_le_channel_opened(channel, result); 3422 3423 // discard channel 3424 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3425 l2cap_free_channel_entry(channel); 3426 break; 3427 } 3428 3429 // success 3430 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3431 channel->remote_mtu = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 3432 channel->remote_mps = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 4); 3433 channel->credits_outgoing = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 6); 3434 channel->state = L2CAP_STATE_OPEN; 3435 l2cap_emit_le_channel_opened(channel, result); 3436 break; 3437 3438 case LE_FLOW_CONTROL_CREDIT: 3439 // check size 3440 if (len < 4u) return 0u; 3441 3442 // find channel 3443 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3444 channel = l2cap_get_channel_for_local_cid_and_handle(local_cid, handle); 3445 if (!channel) { 3446 log_error("credit: no channel for cid 0x%02x", local_cid); 3447 break; 3448 } 3449 new_credits = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 3450 credits_before = channel->credits_outgoing; 3451 channel->credits_outgoing += new_credits; 3452 // check for credit overrun 3453 if (credits_before > channel->credits_outgoing){ 3454 log_error("credit: new credits caused overrrun for cid 0x%02x, disconnecting", local_cid); 3455 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3456 break; 3457 } 3458 log_info("credit: %u credits for 0x%02x, now %u", new_credits, local_cid, channel->credits_outgoing); 3459 break; 3460 3461 case DISCONNECTION_REQUEST: 3462 3463 // check size 3464 if (len < 4u) return 0u; 3465 3466 // find channel 3467 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3468 channel = l2cap_get_channel_for_local_cid_and_handle(local_cid, handle); 3469 if (!channel) { 3470 log_error("credit: no channel for cid 0x%02x", local_cid); 3471 break; 3472 } 3473 channel->remote_sig_id = sig_id; 3474 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 3475 break; 3476 3477 #endif 3478 3479 case DISCONNECTION_RESPONSE: 3480 break; 3481 3482 default: 3483 // command unknown -> reject command 3484 return 0; 3485 } 3486 return 1; 3487 } 3488 #endif 3489 3490 #ifdef ENABLE_CLASSIC 3491 static void l2cap_acl_classic_handler_for_channel(l2cap_channel_t * l2cap_channel, uint8_t * packet, uint16_t size){ 3492 3493 // forward data only in OPEN state 3494 if (l2cap_channel->state != L2CAP_STATE_OPEN) return; 3495 3496 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3497 if (l2cap_channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 3498 3499 int fcs_size = l2cap_channel->fcs_option ? 2 : 0; 3500 3501 // assert control + FCS fields are inside 3502 if (size < COMPLETE_L2CAP_HEADER+2+fcs_size) return; 3503 3504 if (l2cap_channel->fcs_option){ 3505 // verify FCS (required if one side requested it) 3506 uint16_t fcs_calculated = crc16_calc(&packet[4], size - (4+2)); 3507 uint16_t fcs_packet = little_endian_read_16(packet, size-2); 3508 3509 #ifdef L2CAP_ERTM_SIMULATE_FCS_ERROR_INTERVAL 3510 // simulate fcs error 3511 static int counter = 0; 3512 if (++counter == L2CAP_ERTM_SIMULATE_FCS_ERROR_INTERVAL) { 3513 log_info("Simulate fcs error"); 3514 fcs_calculated++; 3515 counter = 0; 3516 } 3517 #endif 3518 3519 if (fcs_calculated == fcs_packet){ 3520 log_info("Packet FCS 0x%04x verified", fcs_packet); 3521 } else { 3522 log_error("FCS mismatch! Packet 0x%04x, calculated 0x%04x", fcs_packet, fcs_calculated); 3523 // ERTM State Machine in Bluetooth Spec does not handle 'I-Frame with invalid FCS' 3524 return; 3525 } 3526 } 3527 3528 // switch on packet type 3529 uint16_t control = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3530 uint8_t req_seq = (control >> 8) & 0x3f; 3531 int final = (control >> 7) & 0x01; 3532 if (control & 1){ 3533 // S-Frame 3534 int poll = (control >> 4) & 0x01; 3535 l2cap_supervisory_function_t s = (l2cap_supervisory_function_t) ((control >> 2) & 0x03); 3536 log_info("Control: 0x%04x => Supervisory function %u, ReqSeq %02u", control, (int) s, req_seq); 3537 l2cap_ertm_tx_packet_state_t * tx_state; 3538 switch (s){ 3539 case L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY: 3540 log_info("L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY"); 3541 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3542 if (poll && final){ 3543 // S-frames shall not be transmitted with both the F-bit and the P-bit set to 1 at the same time. 3544 log_error("P=F=1 in S-Frame"); 3545 break; 3546 } 3547 if (poll){ 3548 // check if we did request selective retransmission before <==> we have stored SDU segments 3549 int i; 3550 int num_stored_out_of_order_packets = 0; 3551 for (i=0;i<l2cap_channel->num_rx_buffers;i++){ 3552 int index = l2cap_channel->rx_store_index + i; 3553 if (index >= l2cap_channel->num_rx_buffers){ 3554 index -= l2cap_channel->num_rx_buffers; 3555 } 3556 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3557 if (!rx_state->valid) continue; 3558 num_stored_out_of_order_packets++; 3559 } 3560 if (num_stored_out_of_order_packets){ 3561 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3562 } else { 3563 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3564 } 3565 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = 1; 3566 } 3567 if (final){ 3568 // Stop-MonitorTimer 3569 l2cap_ertm_stop_monitor_timer(l2cap_channel); 3570 // If UnackedFrames > 0 then Start-RetransTimer 3571 if (l2cap_channel->unacked_frames){ 3572 l2cap_ertm_start_retransmission_timer(l2cap_channel); 3573 } 3574 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3575 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3576 } 3577 break; 3578 case L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT: 3579 log_info("L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT"); 3580 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3581 // restart transmittion from last unacknowledted packet (earlier packets already freed in l2cap_ertm_process_req_seq) 3582 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3583 break; 3584 case L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY: 3585 log_error("L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY"); 3586 break; 3587 case L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT: 3588 log_info("L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT"); 3589 if (poll){ 3590 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3591 } 3592 // find requested i-frame 3593 tx_state = l2cap_ertm_get_tx_state(l2cap_channel, req_seq); 3594 if (tx_state){ 3595 log_info("Retransmission for tx_seq %u requested", req_seq); 3596 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = poll; 3597 tx_state->retransmission_requested = 1; 3598 l2cap_channel->srej_active = 1; 3599 } 3600 break; 3601 default: 3602 break; 3603 } 3604 } else { 3605 // I-Frame 3606 // get control 3607 l2cap_segmentation_and_reassembly_t sar = (l2cap_segmentation_and_reassembly_t) (control >> 14); 3608 uint8_t tx_seq = (control >> 1) & 0x3f; 3609 log_info("Control: 0x%04x => SAR %u, ReqSeq %02u, R?, TxSeq %02u", control, (int) sar, req_seq, tx_seq); 3610 log_info("SAR: pos %u", l2cap_channel->reassembly_pos); 3611 log_info("State: expected_tx_seq %02u, req_seq %02u", l2cap_channel->expected_tx_seq, l2cap_channel->req_seq); 3612 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3613 if (final){ 3614 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3615 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3616 } 3617 3618 // get SDU 3619 const uint8_t * payload_data = &packet[COMPLETE_L2CAP_HEADER+2]; 3620 uint16_t payload_len = size-(COMPLETE_L2CAP_HEADER+2+fcs_size); 3621 3622 // assert SDU size is smaller or equal to our buffers 3623 uint16_t max_payload_size = 0; 3624 switch (sar){ 3625 case L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU: 3626 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 3627 // SDU Length + MPS 3628 max_payload_size = l2cap_channel->local_mps + 2; 3629 break; 3630 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 3631 case L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU: 3632 max_payload_size = l2cap_channel->local_mps; 3633 break; 3634 default: 3635 btstack_assert(false); 3636 break; 3637 } 3638 if (payload_len > max_payload_size){ 3639 log_info("payload len %u > max payload %u -> drop packet", payload_len, max_payload_size); 3640 return; 3641 } 3642 3643 // check ordering 3644 if (l2cap_channel->expected_tx_seq == tx_seq){ 3645 log_info("Received expected frame with TxSeq == ExpectedTxSeq == %02u", tx_seq); 3646 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3647 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3648 3649 // process SDU 3650 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, sar, payload_data, payload_len); 3651 3652 // process stored segments 3653 while (true){ 3654 int index = l2cap_channel->rx_store_index; 3655 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3656 if (!rx_state->valid) break; 3657 3658 log_info("Processing stored frame with TxSeq == ExpectedTxSeq == %02u", l2cap_channel->expected_tx_seq); 3659 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3660 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3661 3662 rx_state->valid = 0; 3663 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, rx_state->sar, &l2cap_channel->rx_packets_data[index], rx_state->len); 3664 3665 // update rx store index 3666 index++; 3667 if (index >= l2cap_channel->num_rx_buffers){ 3668 index = 0; 3669 } 3670 l2cap_channel->rx_store_index = index; 3671 } 3672 3673 // 3674 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3675 3676 } else { 3677 int delta = (tx_seq - l2cap_channel->expected_tx_seq) & 0x3f; 3678 if (delta < 2){ 3679 // store segment 3680 l2cap_ertm_handle_out_of_sequence_sdu(l2cap_channel, sar, delta, payload_data, payload_len); 3681 3682 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-SREJ", tx_seq, l2cap_channel->expected_tx_seq); 3683 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3684 } else { 3685 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-REJ", tx_seq, l2cap_channel->expected_tx_seq); 3686 l2cap_channel->send_supervisor_frame_reject = 1; 3687 } 3688 } 3689 } 3690 return; 3691 } 3692 #endif 3693 3694 // check size 3695 uint16_t payload_size = size - COMPLETE_L2CAP_HEADER; 3696 if (l2cap_channel->local_mtu < payload_size) return; 3697 3698 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], payload_size); 3699 } 3700 #endif 3701 3702 static void l2cap_acl_classic_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3703 #ifdef ENABLE_CLASSIC 3704 l2cap_channel_t * l2cap_channel; 3705 l2cap_fixed_channel_t * l2cap_fixed_channel; 3706 3707 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3708 uint8_t broadcast_flag = READ_ACL_FLAGS(packet) >> 2; 3709 switch (channel_id) { 3710 3711 case L2CAP_CID_SIGNALING: { 3712 if (broadcast_flag != 0) break; 3713 uint32_t command_offset = 8; 3714 while ((command_offset + L2CAP_SIGNALING_COMMAND_DATA_OFFSET) < size) { 3715 // assert signaling command is fully inside packet 3716 uint16_t data_len = little_endian_read_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3717 uint32_t next_command_offset = command_offset + L2CAP_SIGNALING_COMMAND_DATA_OFFSET + data_len; 3718 if (next_command_offset > size){ 3719 log_error("l2cap signaling command len invalid -> drop"); 3720 break; 3721 } 3722 // handle signaling command 3723 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 3724 // go to next command 3725 command_offset = next_command_offset; 3726 } 3727 break; 3728 } 3729 3730 case L2CAP_CID_CONNECTIONLESS_CHANNEL: 3731 if (broadcast_flag == 0) break; 3732 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_CONNECTIONLESS_CHANNEL); 3733 if (!l2cap_fixed_channel) break; 3734 if (!l2cap_fixed_channel->packet_handler) break; 3735 (*l2cap_fixed_channel->packet_handler)(UCD_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3736 break; 3737 3738 #ifdef ENABLE_BLE 3739 case L2CAP_CID_BR_EDR_SECURITY_MANAGER: 3740 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3741 if ((l2cap_fixed_channel == NULL) || (l2cap_fixed_channel->packet_handler == NULL)){ 3742 // Pairing Failed 3743 l2cap_register_signaling_response(handle, (uint8_t) SM_PAIRING_FAILED, 0, L2CAP_CID_BR_EDR_SECURITY_MANAGER, SM_REASON_PAIRING_NOT_SUPPORTED); 3744 } else { 3745 (*l2cap_fixed_channel->packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3746 } 3747 break; 3748 #endif 3749 3750 default: 3751 if (broadcast_flag != 0) break; 3752 // Find channel for this channel_id and connection handle 3753 l2cap_channel = l2cap_get_channel_for_local_cid_and_handle(channel_id, handle); 3754 if (l2cap_channel != NULL){ 3755 l2cap_acl_classic_handler_for_channel(l2cap_channel, packet, size); 3756 } 3757 break; 3758 } 3759 #else 3760 UNUSED(handle); // ok: no code 3761 UNUSED(packet); // ok: no code 3762 UNUSED(size); // ok: no code 3763 #endif 3764 } 3765 3766 static void l2cap_acl_le_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3767 #ifdef ENABLE_BLE 3768 3769 l2cap_fixed_channel_t * l2cap_fixed_channel; 3770 3771 #ifdef ENABLE_LE_DATA_CHANNELS 3772 l2cap_channel_t * l2cap_channel; 3773 #endif 3774 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3775 switch (channel_id) { 3776 3777 case L2CAP_CID_SIGNALING_LE: { 3778 uint16_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1]; 3779 uint16_t len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER + 2); 3780 if ((COMPLETE_L2CAP_HEADER + 4u + len) > size) break; 3781 int valid = l2cap_le_signaling_handler_dispatch(handle, &packet[COMPLETE_L2CAP_HEADER], sig_id); 3782 if (!valid){ 3783 l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3784 } 3785 break; 3786 } 3787 3788 case L2CAP_CID_ATTRIBUTE_PROTOCOL: 3789 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_ATTRIBUTE_PROTOCOL); 3790 if (!l2cap_fixed_channel) break; 3791 if (!l2cap_fixed_channel->packet_handler) break; 3792 (*l2cap_fixed_channel->packet_handler)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3793 break; 3794 3795 case L2CAP_CID_SECURITY_MANAGER_PROTOCOL: 3796 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3797 if ((l2cap_fixed_channel == NULL) || (l2cap_fixed_channel->packet_handler == NULL)){ 3798 // Pairing Failed 3799 l2cap_register_signaling_response(handle, (uint8_t) SM_PAIRING_FAILED, 0, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, SM_REASON_PAIRING_NOT_SUPPORTED); 3800 } else { 3801 (*l2cap_fixed_channel->packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3802 } 3803 break; 3804 3805 default: 3806 3807 #ifdef ENABLE_LE_DATA_CHANNELS 3808 l2cap_channel = l2cap_get_channel_for_local_cid_and_handle(channel_id, handle); 3809 if (l2cap_channel != NULL) { 3810 // credit counting 3811 if (l2cap_channel->credits_incoming == 0u){ 3812 log_info("LE Data Channel packet received but no incoming credits"); 3813 l2cap_channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3814 break; 3815 } 3816 l2cap_channel->credits_incoming--; 3817 3818 // automatic credits 3819 if ((l2cap_channel->credits_incoming < L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_WATERMARK) && l2cap_channel->automatic_credits){ 3820 l2cap_channel->new_credits_incoming = L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_INCREMENT; 3821 } 3822 3823 // first fragment 3824 uint16_t pos = 0; 3825 if (!l2cap_channel->receive_sdu_len){ 3826 uint16_t sdu_len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3827 if(sdu_len > l2cap_channel->local_mtu) break; // SDU would be larger than our buffer 3828 l2cap_channel->receive_sdu_len = sdu_len; 3829 l2cap_channel->receive_sdu_pos = 0; 3830 pos += 2u; 3831 size -= 2u; 3832 } 3833 uint16_t fragment_size = size-COMPLETE_L2CAP_HEADER; 3834 uint16_t remaining_space = l2cap_channel->local_mtu - l2cap_channel->receive_sdu_pos; 3835 if (fragment_size > remaining_space) break; // SDU would cause buffer overrun 3836 (void)memcpy(&l2cap_channel->receive_sdu_buffer[l2cap_channel->receive_sdu_pos], 3837 &packet[COMPLETE_L2CAP_HEADER + pos], 3838 fragment_size); 3839 l2cap_channel->receive_sdu_pos += size - COMPLETE_L2CAP_HEADER; 3840 // done? 3841 log_debug("le packet pos %u, len %u", l2cap_channel->receive_sdu_pos, l2cap_channel->receive_sdu_len); 3842 if (l2cap_channel->receive_sdu_pos >= l2cap_channel->receive_sdu_len){ 3843 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, l2cap_channel->receive_sdu_buffer, l2cap_channel->receive_sdu_len); 3844 l2cap_channel->receive_sdu_len = 0; 3845 } 3846 } 3847 #endif 3848 break; 3849 } 3850 #else 3851 UNUSED(handle); // ok: no code 3852 UNUSED(packet); // ok: no code 3853 UNUSED(size); // ok: no code 3854 #endif 3855 } 3856 3857 static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3858 UNUSED(packet_type); // ok: registered with hci_register_acl_packet_handler 3859 UNUSED(channel); // ok: there is no channel 3860 3861 // Assert full L2CAP header present 3862 if (size < COMPLETE_L2CAP_HEADER) return; 3863 3864 // Dispatch to Classic or LE handler (SCO packets are not dispatched to L2CAP) 3865 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 3866 hci_connection_t *conn = hci_connection_for_handle(handle); 3867 if (!conn) return; 3868 if (conn->address_type == BD_ADDR_TYPE_ACL){ 3869 l2cap_acl_classic_handler(handle, packet, size); 3870 } else { 3871 l2cap_acl_le_handler(handle, packet, size); 3872 } 3873 3874 l2cap_run(); 3875 } 3876 3877 // Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol 3878 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id) { 3879 l2cap_fixed_channel_t * channel = l2cap_fixed_channel_for_channel_id(channel_id); 3880 if (!channel) return; 3881 channel->packet_handler = packet_handler; 3882 } 3883 3884 #ifdef ENABLE_CLASSIC 3885 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 3886 void l2cap_finialize_channel_close(l2cap_channel_t * channel){ 3887 channel->state = L2CAP_STATE_CLOSED; 3888 l2cap_handle_channel_closed(channel); 3889 // discard channel 3890 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3891 l2cap_free_channel_entry(channel); 3892 } 3893 #endif 3894 3895 #ifdef L2CAP_USES_CHANNELS 3896 static l2cap_service_t * l2cap_get_service_internal(btstack_linked_list_t * services, uint16_t psm){ 3897 btstack_linked_list_iterator_t it; 3898 btstack_linked_list_iterator_init(&it, services); 3899 while (btstack_linked_list_iterator_has_next(&it)){ 3900 l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it); 3901 if ( service->psm == psm){ 3902 return service; 3903 }; 3904 } 3905 return NULL; 3906 } 3907 #endif 3908 3909 #ifdef ENABLE_CLASSIC 3910 static inline l2cap_service_t * l2cap_get_service(uint16_t psm){ 3911 return l2cap_get_service_internal(&l2cap_services, psm); 3912 } 3913 3914 static void l2cap_update_minimal_security_level(void){ 3915 // update minimal service security level 3916 gap_security_level_t minimal_level = LEVEL_1; 3917 btstack_linked_list_iterator_t it; 3918 btstack_linked_list_iterator_init(&it, &l2cap_services); 3919 while (btstack_linked_list_iterator_has_next(&it)){ 3920 l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it); 3921 if (service->required_security_level > minimal_level){ 3922 minimal_level = service->required_security_level; 3923 }; 3924 } 3925 gap_set_minimal_service_security_level(minimal_level); 3926 } 3927 3928 uint8_t l2cap_register_service(btstack_packet_handler_t service_packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level){ 3929 3930 log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u", psm, mtu); 3931 3932 // check for alread registered psm 3933 l2cap_service_t *service = l2cap_get_service(psm); 3934 if (service) { 3935 log_error("register: PSM %u already registered", psm); 3936 return L2CAP_SERVICE_ALREADY_REGISTERED; 3937 } 3938 3939 // alloc structure 3940 service = btstack_memory_l2cap_service_get(); 3941 if (!service) { 3942 log_error("register: no memory for l2cap_service_t"); 3943 return BTSTACK_MEMORY_ALLOC_FAILED; 3944 } 3945 3946 // fill in 3947 service->psm = psm; 3948 service->mtu = mtu; 3949 service->packet_handler = service_packet_handler; 3950 service->required_security_level = security_level; 3951 3952 // add to services list 3953 btstack_linked_list_add(&l2cap_services, (btstack_linked_item_t *) service); 3954 3955 l2cap_update_minimal_security_level(); 3956 3957 #ifndef ENABLE_EXPLICIT_CONNECTABLE_MODE_CONTROL 3958 // enable page scan 3959 gap_connectable_control(1); 3960 #endif 3961 3962 3963 return ERROR_CODE_SUCCESS; 3964 } 3965 3966 uint8_t l2cap_unregister_service(uint16_t psm){ 3967 3968 log_info("unregister psm 0x%x", psm); 3969 3970 l2cap_service_t *service = l2cap_get_service(psm); 3971 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 3972 btstack_linked_list_remove(&l2cap_services, (btstack_linked_item_t *) service); 3973 btstack_memory_l2cap_service_free(service); 3974 3975 l2cap_update_minimal_security_level(); 3976 3977 #ifndef ENABLE_EXPLICIT_CONNECTABLE_MODE_CONTROL 3978 // disable page scan when no services registered 3979 if (btstack_linked_list_empty(&l2cap_services)) { 3980 gap_connectable_control(0); 3981 } 3982 #endif 3983 3984 return ERROR_CODE_SUCCESS; 3985 } 3986 #endif 3987 3988 3989 #ifdef ENABLE_LE_DATA_CHANNELS 3990 3991 static void l2cap_le_notify_channel_can_send(l2cap_channel_t *channel){ 3992 if (!channel->waiting_for_can_send_now) return; 3993 if (channel->send_sdu_buffer) return; 3994 channel->waiting_for_can_send_now = 0; 3995 log_debug("le can send now, local_cid 0x%x", channel->local_cid); 3996 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_CAN_SEND_NOW); 3997 } 3998 3999 // 1BH2222 4000 static void l2cap_emit_le_incoming_connection(l2cap_channel_t *channel) { 4001 log_info("le incoming addr_type %u, addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x, remote_mtu %u", 4002 channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, channel->local_cid, channel->remote_cid, channel->remote_mtu); 4003 uint8_t event[19]; 4004 event[0] = L2CAP_EVENT_LE_INCOMING_CONNECTION; 4005 event[1] = sizeof(event) - 2u; 4006 event[2] = channel->address_type; 4007 reverse_bd_addr(channel->address, &event[3]); 4008 little_endian_store_16(event, 9, channel->con_handle); 4009 little_endian_store_16(event, 11, channel->psm); 4010 little_endian_store_16(event, 13, channel->local_cid); 4011 little_endian_store_16(event, 15, channel->remote_cid); 4012 little_endian_store_16(event, 17, channel->remote_mtu); 4013 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4014 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4015 } 4016 // 11BH22222 4017 static void l2cap_emit_le_channel_opened(l2cap_channel_t *channel, uint8_t status) { 4018 log_info("opened le channel 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", 4019 status, channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, 4020 channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu); 4021 uint8_t event[23]; 4022 event[0] = L2CAP_EVENT_LE_CHANNEL_OPENED; 4023 event[1] = sizeof(event) - 2u; 4024 event[2] = status; 4025 event[3] = channel->address_type; 4026 reverse_bd_addr(channel->address, &event[4]); 4027 little_endian_store_16(event, 10, channel->con_handle); 4028 event[12] = (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) ? 1 : 0; 4029 little_endian_store_16(event, 13, channel->psm); 4030 little_endian_store_16(event, 15, channel->local_cid); 4031 little_endian_store_16(event, 17, channel->remote_cid); 4032 little_endian_store_16(event, 19, channel->local_mtu); 4033 little_endian_store_16(event, 21, channel->remote_mtu); 4034 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4035 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4036 } 4037 // 2 4038 static void l2cap_emit_le_channel_closed(l2cap_channel_t * channel){ 4039 log_info("closed local_cid 0x%x", channel->local_cid); 4040 uint8_t event[4]; 4041 event[0] = L2CAP_EVENT_LE_CHANNEL_CLOSED; 4042 event[1] = sizeof(event) - 2u; 4043 little_endian_store_16(event, 2, channel->local_cid); 4044 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4045 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4046 } 4047 4048 static void l2cap_le_send_pdu(l2cap_channel_t *channel){ 4049 btstack_assert(channel != NULL); 4050 btstack_assert(channel->send_sdu_buffer != NULL); 4051 btstack_assert(channel->credits_outgoing > 0); 4052 4053 // send part of SDU 4054 hci_reserve_packet_buffer(); 4055 uint8_t * acl_buffer = hci_get_outgoing_packet_buffer(); 4056 uint8_t * l2cap_payload = acl_buffer + 8; 4057 uint16_t pos = 0; 4058 if (!channel->send_sdu_pos){ 4059 // store SDU len 4060 channel->send_sdu_pos += 2u; 4061 little_endian_store_16(l2cap_payload, pos, channel->send_sdu_len); 4062 pos += 2u; 4063 } 4064 uint16_t payload_size = btstack_min(channel->send_sdu_len + 2u - channel->send_sdu_pos, channel->remote_mps - pos); 4065 log_info("len %u, pos %u => payload %u, credits %u", channel->send_sdu_len, channel->send_sdu_pos, payload_size, channel->credits_outgoing); 4066 (void)memcpy(&l2cap_payload[pos], 4067 &channel->send_sdu_buffer[channel->send_sdu_pos - 2u], 4068 payload_size); // -2 for virtual SDU len 4069 pos += payload_size; 4070 channel->send_sdu_pos += payload_size; 4071 l2cap_setup_header(acl_buffer, channel->con_handle, 0, channel->remote_cid, pos); 4072 4073 channel->credits_outgoing--; 4074 4075 hci_send_acl_packet_buffer(8u + pos); 4076 4077 if (channel->send_sdu_pos >= (channel->send_sdu_len + 2u)){ 4078 channel->send_sdu_buffer = NULL; 4079 // send done event 4080 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_PACKET_SENT); 4081 // inform about can send now 4082 l2cap_le_notify_channel_can_send(channel); 4083 } 4084 } 4085 4086 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 4087 void l2cap_le_finialize_channel_close(l2cap_channel_t * channel){ 4088 channel->state = L2CAP_STATE_CLOSED; 4089 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_CHANNEL_CLOSED); 4090 // discard channel 4091 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 4092 l2cap_free_channel_entry(channel); 4093 } 4094 4095 static inline l2cap_service_t * l2cap_le_get_service(uint16_t le_psm){ 4096 return l2cap_get_service_internal(&l2cap_le_services, le_psm); 4097 } 4098 4099 uint8_t l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level){ 4100 4101 log_info("L2CAP_LE_REGISTER_SERVICE psm 0x%x", psm); 4102 4103 // check for alread registered psm 4104 l2cap_service_t *service = l2cap_le_get_service(psm); 4105 if (service) { 4106 return L2CAP_SERVICE_ALREADY_REGISTERED; 4107 } 4108 4109 // alloc structure 4110 service = btstack_memory_l2cap_service_get(); 4111 if (!service) { 4112 log_error("register: no memory for l2cap_service_t"); 4113 return BTSTACK_MEMORY_ALLOC_FAILED; 4114 } 4115 4116 // fill in 4117 service->psm = psm; 4118 service->mtu = 0; 4119 service->packet_handler = packet_handler; 4120 service->required_security_level = security_level; 4121 4122 // add to services list 4123 btstack_linked_list_add(&l2cap_le_services, (btstack_linked_item_t *) service); 4124 4125 // done 4126 return ERROR_CODE_SUCCESS; 4127 } 4128 4129 uint8_t l2cap_le_unregister_service(uint16_t psm) { 4130 log_info("L2CAP_LE_UNREGISTER_SERVICE psm 0x%x", psm); 4131 l2cap_service_t *service = l2cap_le_get_service(psm); 4132 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 4133 4134 btstack_linked_list_remove(&l2cap_le_services, (btstack_linked_item_t *) service); 4135 btstack_memory_l2cap_service_free(service); 4136 return ERROR_CODE_SUCCESS; 4137 } 4138 4139 uint8_t l2cap_le_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits){ 4140 // get channel 4141 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4142 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4143 4144 // validate state 4145 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 4146 return ERROR_CODE_COMMAND_DISALLOWED; 4147 } 4148 4149 // set state accept connection 4150 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT; 4151 channel->receive_sdu_buffer = receive_sdu_buffer; 4152 channel->local_mtu = mtu; 4153 channel->new_credits_incoming = initial_credits; 4154 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 4155 4156 // test 4157 // channel->new_credits_incoming = 1; 4158 4159 // go 4160 l2cap_run(); 4161 return ERROR_CODE_SUCCESS; 4162 } 4163 4164 /** 4165 * @brief Deny incoming LE Data Channel connection due to resource constraints 4166 * @param local_cid L2CAP LE Data Channel Identifier 4167 */ 4168 4169 uint8_t l2cap_le_decline_connection(uint16_t local_cid){ 4170 // get channel 4171 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4172 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4173 4174 // validate state 4175 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 4176 return ERROR_CODE_COMMAND_DISALLOWED; 4177 } 4178 4179 // set state decline connection 4180 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE; 4181 channel->reason = 0x04; // no resources available 4182 l2cap_run(); 4183 return ERROR_CODE_SUCCESS; 4184 } 4185 4186 static gap_security_level_t l2cap_le_security_level_for_connection(hci_con_handle_t con_handle){ 4187 uint8_t encryption_key_size = gap_encryption_key_size(con_handle); 4188 if (encryption_key_size == 0) return LEVEL_0; 4189 4190 uint8_t authenticated = gap_authenticated(con_handle); 4191 if (!authenticated) return LEVEL_2; 4192 4193 return encryption_key_size == 16 ? LEVEL_4 : LEVEL_3; 4194 } 4195 4196 // used to handle pairing complete after triggering to increase 4197 static void l2cap_sm_packet_handler(uint8_t packet_type, uint16_t channel_nr, uint8_t *packet, uint16_t size) { 4198 UNUSED(channel_nr); 4199 UNUSED(size); 4200 UNUSED(packet_type); 4201 btstack_assert(packet_type == HCI_EVENT_PACKET); 4202 if (hci_event_packet_get_type(packet) != SM_EVENT_PAIRING_COMPLETE) return; 4203 hci_con_handle_t con_handle = sm_event_pairing_complete_get_handle(packet); 4204 btstack_linked_list_iterator_t it; 4205 btstack_linked_list_iterator_init(&it, &l2cap_channels); 4206 while (btstack_linked_list_iterator_has_next(&it)) { 4207 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 4208 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 4209 if (channel->con_handle != con_handle) continue; 4210 if (channel->state != L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE) continue; 4211 4212 // found channel, check security level 4213 if (l2cap_le_security_level_for_connection(con_handle) < channel->required_security_level){ 4214 // pairing failed or wasn't good enough, inform user 4215 l2cap_emit_le_channel_opened(channel, ERROR_CODE_INSUFFICIENT_SECURITY); 4216 // discard channel 4217 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 4218 l2cap_free_channel_entry(channel); 4219 } else { 4220 // send conn request now 4221 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST; 4222 l2cap_run(); 4223 } 4224 } 4225 } 4226 4227 uint8_t l2cap_le_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, 4228 uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level, 4229 uint16_t * out_local_cid) { 4230 4231 static btstack_packet_callback_registration_t sm_event_callback_registration; 4232 static bool sm_callback_registered = false; 4233 4234 log_info("create, handle 0x%04x psm 0x%x mtu %u", con_handle, psm, mtu); 4235 4236 hci_connection_t * connection = hci_connection_for_handle(con_handle); 4237 if (!connection) { 4238 log_error("no hci_connection for handle 0x%04x", con_handle); 4239 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 4240 } 4241 4242 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); 4243 if (!channel) { 4244 return BTSTACK_MEMORY_ALLOC_FAILED; 4245 } 4246 log_info("created %p", channel); 4247 4248 // store local_cid 4249 if (out_local_cid){ 4250 *out_local_cid = channel->local_cid; 4251 } 4252 4253 // setup channel entry 4254 channel->con_handle = con_handle; 4255 channel->receive_sdu_buffer = receive_sdu_buffer; 4256 channel->new_credits_incoming = initial_credits; 4257 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 4258 4259 // add to connections list 4260 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 4261 4262 // check security level 4263 if (l2cap_le_security_level_for_connection(con_handle) < channel->required_security_level){ 4264 if (!sm_callback_registered){ 4265 sm_callback_registered = true; 4266 // lazy registration for SM events 4267 sm_event_callback_registration.callback = &l2cap_sm_packet_handler; 4268 sm_add_event_handler(&sm_event_callback_registration); 4269 } 4270 4271 // start pairing 4272 channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE; 4273 sm_request_pairing(con_handle); 4274 } else { 4275 // send conn request right away 4276 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST; 4277 l2cap_run(); 4278 } 4279 4280 return ERROR_CODE_SUCCESS; 4281 } 4282 4283 /** 4284 * @brief Provide credtis for LE Data Channel 4285 * @param local_cid L2CAP LE Data Channel Identifier 4286 * @param credits Number additional credits for peer 4287 */ 4288 uint8_t l2cap_le_provide_credits(uint16_t local_cid, uint16_t credits){ 4289 4290 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4291 if (!channel) { 4292 log_error("le credits no channel for cid 0x%02x", local_cid); 4293 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4294 } 4295 4296 // check state 4297 if (channel->state != L2CAP_STATE_OPEN){ 4298 log_error("le credits but channel 0x%02x not open yet", local_cid); 4299 } 4300 4301 // assert incoming credits + credits <= 0xffff 4302 uint32_t total_credits = channel->credits_incoming; 4303 total_credits += channel->new_credits_incoming; 4304 total_credits += credits; 4305 if (total_credits > 0xffffu){ 4306 log_error("le credits overrun: current %u, scheduled %u, additional %u", channel->credits_incoming, 4307 channel->new_credits_incoming, credits); 4308 } 4309 4310 // set credits_granted 4311 channel->new_credits_incoming += credits; 4312 4313 // go 4314 l2cap_run(); 4315 return ERROR_CODE_SUCCESS; 4316 } 4317 4318 /** 4319 * @brief Check if outgoing buffer is available and that there's space on the Bluetooth module 4320 * @param local_cid L2CAP LE Data Channel Identifier 4321 */ 4322 bool l2cap_le_can_send_now(uint16_t local_cid){ 4323 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4324 if (!channel) { 4325 log_error("le can send now, no channel for cid 0x%02x", local_cid); 4326 return false; 4327 } 4328 4329 // check state 4330 if (channel->state != L2CAP_STATE_OPEN) return false; 4331 4332 // check queue 4333 if (channel->send_sdu_buffer) return false; 4334 4335 // fine, go ahead 4336 return true; 4337 } 4338 4339 /** 4340 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible 4341 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 4342 * so packet handler should be ready to handle it 4343 * @param local_cid L2CAP LE Data Channel Identifier 4344 */ 4345 uint8_t l2cap_le_request_can_send_now_event(uint16_t local_cid){ 4346 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4347 if (!channel) { 4348 log_error("can send now, no channel for cid 0x%02x", local_cid); 4349 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4350 } 4351 channel->waiting_for_can_send_now = 1; 4352 l2cap_le_notify_channel_can_send(channel); 4353 return ERROR_CODE_SUCCESS; 4354 } 4355 4356 /** 4357 * @brief Send data via LE Data Channel 4358 * @note Since data larger then the maximum PDU needs to be segmented into multiple PDUs, data needs to stay valid until ... event 4359 * @param local_cid L2CAP LE Data Channel Identifier 4360 * @param data data to send 4361 * @param size data size 4362 */ 4363 uint8_t l2cap_le_send_data(uint16_t local_cid, uint8_t * data, uint16_t size){ 4364 4365 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4366 if (!channel) { 4367 log_error("l2cap send, no channel for cid 0x%02x", local_cid); 4368 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4369 } 4370 4371 if (size > channel->remote_mtu){ 4372 log_error("l2cap send, cid 0x%02x, data length exceeds remote MTU.", local_cid); 4373 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 4374 } 4375 4376 if (channel->send_sdu_buffer){ 4377 log_info("l2cap send, cid 0x%02x, cannot send", local_cid); 4378 return BTSTACK_ACL_BUFFERS_FULL; 4379 } 4380 4381 channel->send_sdu_buffer = data; 4382 channel->send_sdu_len = size; 4383 channel->send_sdu_pos = 0; 4384 4385 l2cap_notify_channel_can_send(); 4386 return ERROR_CODE_SUCCESS; 4387 } 4388 4389 /** 4390 * @brief Disconnect from LE Data Channel 4391 * @param local_cid L2CAP LE Data Channel Identifier 4392 */ 4393 uint8_t l2cap_le_disconnect(uint16_t local_cid) 4394 { 4395 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4396 if (!channel) { 4397 log_error("l2cap send, no channel for cid 0x%02x", local_cid); 4398 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4399 } 4400 4401 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 4402 l2cap_run(); 4403 return ERROR_CODE_SUCCESS; 4404 } 4405 4406 #endif 4407