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_handle_connection_complete(hci_con_handle_t con_handle, l2cap_channel_t * channel){ 1954 if ((channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE) || (channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION)) { 1955 log_info("connection complete con_handle %04x - for channel %p cid 0x%04x", (int) con_handle, channel, channel->local_cid); 1956 // success, start l2cap handshake 1957 channel->con_handle = con_handle; 1958 // we require remote features to check SSP 1959 channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES; 1960 hci_remote_features_query(con_handle); 1961 } 1962 } 1963 1964 static void l2cap_ready_to_connect(l2cap_channel_t * channel){ 1965 1966 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 1967 // assumption: outgoing connection 1968 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 1969 if (connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_IDLE){ 1970 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 1971 channel->state = L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES; 1972 return; 1973 } 1974 #endif 1975 1976 // fine, go ahead 1977 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 1978 } 1979 1980 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){ 1981 if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return; 1982 // double check if all feature pages are complete 1983 1984 bool security_required = channel->required_security_level > LEVEL_0; 1985 1986 // abort if Secure Connections Only Mode with legacy connection 1987 if (security_required && gap_get_secure_connections_only_mode() && gap_secure_connection(channel->con_handle) == 0){ 1988 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY); 1989 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 1990 l2cap_free_channel_entry(channel); 1991 return; 1992 } 1993 1994 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) != 0){ 1995 1996 // Core V5.2, Vol 3, Part C, 5.2.2.2 - Security Mode 4 1997 // When a remote device attempts to access a service offered by a Bluetooth device that is in security mode 4 1998 // and a sufficient link key exists and authentication has not been performed the local device shall authenticate 1999 // the remote device and enable encryption after the channel establishment request is received but before a channel 2000 // establishment confirmation (L2CAP_ConnectRsp with result code of 0x0000 or a higher-level channel establishment 2001 // confirmation such as that of RFCOMM) is sent. 2002 2003 // If the remote device has indicated support for Secure Simple Pairing, a channel establishment request is 2004 // received for a service other than SDP, and encryption has not yet been enabled, then the local device shall 2005 // disconnect the ACL link with error code 0x05 - Authentication Failure. 2006 2007 // => Disconnect if l2cap request received in mode 4 and ssp supported, non-sdp psm, not encrypted, no link key available 2008 if ((gap_get_security_mode() == GAP_SECURITY_MODE_4) 2009 && gap_ssp_supported_on_both_sides(channel->con_handle) 2010 && (channel->psm != PSM_SDP) 2011 && (gap_encryption_key_size(channel->con_handle) == 0) 2012 && (gap_bonded(channel->con_handle) == false)){ 2013 hci_disconnect_security_block(channel->con_handle); 2014 return; 2015 } 2016 2017 // incoming: assert security requirements 2018 channel->state = L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE; 2019 if (channel->required_security_level <= gap_security_level(channel->con_handle)){ 2020 l2cap_handle_security_level_incoming_sufficient(channel); 2021 } else { 2022 // send connection pending if not already done 2023 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONN_RESP_PEND) == 0){ 2024 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND; 2025 } 2026 gap_request_security_level(channel->con_handle, channel->required_security_level); 2027 } 2028 } else { 2029 // outgoing: we have been waiting for remote supported features 2030 if (security_required){ 2031 // request security level 2032 channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE; 2033 gap_request_security_level(channel->con_handle, channel->required_security_level); 2034 } else { 2035 l2cap_ready_to_connect(channel); 2036 } 2037 } 2038 } 2039 #endif 2040 2041 #ifdef L2CAP_USES_CHANNELS 2042 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, 2043 uint16_t psm, uint16_t local_mtu, gap_security_level_t security_level){ 2044 2045 l2cap_channel_t * channel = btstack_memory_l2cap_channel_get(); 2046 if (!channel) { 2047 return NULL; 2048 } 2049 2050 // fill in 2051 channel->packet_handler = packet_handler; 2052 channel->channel_type = channel_type; 2053 bd_addr_copy(channel->address, address); 2054 channel->address_type = address_type; 2055 channel->psm = psm; 2056 channel->local_mtu = local_mtu; 2057 channel->remote_mtu = L2CAP_DEFAULT_MTU; 2058 channel->required_security_level = security_level; 2059 2060 // 2061 channel->local_cid = l2cap_next_local_cid(); 2062 channel->con_handle = HCI_CON_HANDLE_INVALID; 2063 2064 // set initial state 2065 channel->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION; 2066 channel->state_var = L2CAP_CHANNEL_STATE_VAR_NONE; 2067 channel->remote_sig_id = L2CAP_SIG_ID_INVALID; 2068 channel->local_sig_id = L2CAP_SIG_ID_INVALID; 2069 2070 log_info("create channel %p, local_cid 0x%04x", channel, channel->local_cid); 2071 2072 return channel; 2073 } 2074 2075 static void l2cap_free_channel_entry(l2cap_channel_t * channel){ 2076 log_info("free channel %p, local_cid 0x%04x", channel, channel->local_cid); 2077 // assert all timers are stopped 2078 l2cap_stop_rtx(channel); 2079 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2080 l2cap_ertm_stop_retransmission_timer(channel); 2081 l2cap_ertm_stop_monitor_timer(channel); 2082 #endif 2083 // free memory 2084 btstack_memory_l2cap_channel_free(channel); 2085 } 2086 #endif 2087 2088 #ifdef ENABLE_CLASSIC 2089 2090 /** 2091 * @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary. 2092 * @param packet_handler 2093 * @param address 2094 * @param psm 2095 * @param mtu 2096 * @param local_cid 2097 */ 2098 2099 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){ 2100 // limit MTU to the size of our outgoing HCI buffer 2101 uint16_t local_mtu = btstack_min(mtu, l2cap_max_mtu()); 2102 2103 // determine security level based on psm 2104 const gap_security_level_t security_level = l2cap_security_level_0_allowed_for_PSM(psm) ? LEVEL_0 : gap_get_security_level(); 2105 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); 2106 2107 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); 2108 if (!channel) { 2109 return BTSTACK_MEMORY_ALLOC_FAILED; 2110 } 2111 2112 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2113 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2114 #endif 2115 2116 // add to connections list 2117 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2118 2119 // store local_cid 2120 if (out_local_cid){ 2121 *out_local_cid = channel->local_cid; 2122 } 2123 2124 // state: L2CAP_STATE_WILL_SEND_CREATE_CONNECTION 2125 2126 // check if hci connection is already usable, 2127 hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_ACL); 2128 if (conn && conn->state == OPEN){ 2129 // simulate connection complete 2130 l2cap_handle_connection_complete(conn->con_handle, channel); 2131 2132 // state: L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES 2133 2134 // check if remote supported features are already received 2135 if (hci_remote_features_available(conn->con_handle)) { 2136 // simulate remote features received 2137 l2cap_handle_remote_supported_features_received(channel); 2138 } else { 2139 hci_remote_features_query(conn->con_handle); 2140 } 2141 } 2142 2143 l2cap_run(); 2144 2145 return ERROR_CODE_SUCCESS; 2146 } 2147 2148 void l2cap_disconnect(uint16_t local_cid, uint8_t reason){ 2149 log_info("disconnect local_cid 0x%x reason 0x%x", local_cid, reason); 2150 UNUSED(reason); 2151 // find channel for local_cid 2152 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 2153 if (channel) { 2154 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2155 } 2156 // process 2157 l2cap_run(); 2158 } 2159 2160 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){ 2161 // mark all channels before emitting open events as these could trigger new connetion requests to the same device 2162 btstack_linked_list_iterator_t it; 2163 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2164 while (btstack_linked_list_iterator_has_next(&it)){ 2165 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2166 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2167 if (bd_addr_cmp( channel->address, address) != 0) continue; 2168 // channel for this address found 2169 switch (channel->state){ 2170 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 2171 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 2172 channel->state = L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD; 2173 break; 2174 default: 2175 break; 2176 } 2177 } 2178 // emit and free marked entries. restart loop to deal with list changes 2179 int done = 0; 2180 while (!done) { 2181 done = 1; 2182 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2183 while (btstack_linked_list_iterator_has_next(&it)){ 2184 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2185 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2186 if (channel->state == L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD){ 2187 done = 0; 2188 // failure, forward error code 2189 l2cap_handle_channel_open_failed(channel, status); 2190 // discard channel 2191 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2192 l2cap_free_channel_entry(channel); 2193 break; 2194 } 2195 } 2196 } 2197 2198 } 2199 2200 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){ 2201 btstack_linked_list_iterator_t it; 2202 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2203 while (btstack_linked_list_iterator_has_next(&it)){ 2204 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2205 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2206 if ( ! bd_addr_cmp( channel->address, address) ){ 2207 l2cap_handle_connection_complete(handle, channel); 2208 } 2209 } 2210 // process 2211 l2cap_run(); 2212 } 2213 #endif 2214 2215 static bool l2cap_channel_ready_to_send(l2cap_channel_t * channel){ 2216 switch (channel->channel_type){ 2217 #ifdef ENABLE_CLASSIC 2218 case L2CAP_CHANNEL_TYPE_CLASSIC: 2219 if (channel->state != L2CAP_STATE_OPEN) return false; 2220 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2221 // send if we have more data and remote windows isn't full yet 2222 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) { 2223 if (channel->unacked_frames >= btstack_min(channel->num_stored_tx_frames, channel->remote_tx_window_size)) return false; 2224 return hci_can_send_acl_classic_packet_now() != 0; 2225 } 2226 #endif 2227 if (!channel->waiting_for_can_send_now) return false; 2228 return (hci_can_send_acl_classic_packet_now() != 0); 2229 case L2CAP_CHANNEL_TYPE_CONNECTIONLESS: 2230 if (!channel->waiting_for_can_send_now) return false; 2231 return hci_can_send_acl_classic_packet_now() != 0; 2232 #endif 2233 #ifdef ENABLE_BLE 2234 case L2CAP_CHANNEL_TYPE_FIXED: 2235 if (!channel->waiting_for_can_send_now) return false; 2236 return hci_can_send_acl_le_packet_now() != 0; 2237 #ifdef ENABLE_LE_DATA_CHANNELS 2238 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2239 if (channel->state != L2CAP_STATE_OPEN) return false; 2240 if (channel->send_sdu_buffer == NULL) return false; 2241 if (channel->credits_outgoing == 0u) return false; 2242 return hci_can_send_acl_le_packet_now() != 0; 2243 #endif 2244 #endif 2245 default: 2246 return false; 2247 } 2248 } 2249 2250 static void l2cap_channel_trigger_send(l2cap_channel_t * channel){ 2251 switch (channel->channel_type){ 2252 #ifdef ENABLE_CLASSIC 2253 case L2CAP_CHANNEL_TYPE_CLASSIC: 2254 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2255 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) { 2256 l2cap_ertm_channel_send_information_frame(channel); 2257 return; 2258 } 2259 #endif 2260 channel->waiting_for_can_send_now = 0; 2261 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2262 break; 2263 case L2CAP_CHANNEL_TYPE_CONNECTIONLESS: 2264 channel->waiting_for_can_send_now = 0; 2265 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2266 break; 2267 #endif 2268 #ifdef ENABLE_BLE 2269 case L2CAP_CHANNEL_TYPE_FIXED: 2270 channel->waiting_for_can_send_now = 0; 2271 l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid); 2272 break; 2273 #ifdef ENABLE_LE_DATA_CHANNELS 2274 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2275 l2cap_le_send_pdu(channel); 2276 break; 2277 #endif 2278 #endif 2279 default: 2280 break; 2281 } 2282 } 2283 2284 static void l2cap_notify_channel_can_send(void){ 2285 bool done = false; 2286 while (!done){ 2287 done = true; 2288 btstack_linked_list_iterator_t it; 2289 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2290 while (btstack_linked_list_iterator_has_next(&it)){ 2291 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2292 bool ready = l2cap_channel_ready_to_send(channel); 2293 if (!ready) continue; 2294 2295 // requeue channel for fairness 2296 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2297 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2298 2299 // trigger sending 2300 l2cap_channel_trigger_send(channel); 2301 2302 // exit inner loop as we just broke the iterator, but try again 2303 done = false; 2304 break; 2305 } 2306 } 2307 } 2308 2309 #ifdef L2CAP_USES_CHANNELS 2310 2311 static int l2cap_send_open_failed_on_hci_disconnect(l2cap_channel_t * channel){ 2312 // open cannot fail for for incoming connections 2313 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) return 0; 2314 2315 // check state 2316 switch (channel->state){ 2317 case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION: 2318 case L2CAP_STATE_WAIT_CONNECTION_COMPLETE: 2319 case L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES: 2320 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 2321 case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT: 2322 case L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES: 2323 case L2CAP_STATE_WAIT_CONNECT_RSP: 2324 case L2CAP_STATE_CONFIG: 2325 case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST: 2326 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST: 2327 case L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE: 2328 case L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD: 2329 return 1; 2330 2331 case L2CAP_STATE_OPEN: 2332 case L2CAP_STATE_CLOSED: 2333 case L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES: 2334 case L2CAP_STATE_WAIT_DISCONNECT: 2335 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_INSUFFICIENT_SECURITY: 2336 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE: 2337 case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT: 2338 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 2339 case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE: 2340 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE: 2341 case L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT: 2342 case L2CAP_STATE_INVALID: 2343 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 2344 return 0; 2345 2346 default: 2347 // get a "warning" about new states 2348 btstack_assert(false); 2349 return 0; 2350 } 2351 } 2352 #endif 2353 2354 #ifdef ENABLE_CLASSIC 2355 static void l2cap_handle_hci_disconnect_event(l2cap_channel_t * channel){ 2356 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 2357 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 2358 } else { 2359 l2cap_handle_channel_closed(channel); 2360 } 2361 l2cap_free_channel_entry(channel); 2362 } 2363 #endif 2364 2365 #ifdef ENABLE_LE_DATA_CHANNELS 2366 static void l2cap_handle_hci_le_disconnect_event(l2cap_channel_t * channel){ 2367 if (l2cap_send_open_failed_on_hci_disconnect(channel)){ 2368 l2cap_emit_le_channel_opened(channel, L2CAP_CONNECTION_BASEBAND_DISCONNECT); 2369 } else { 2370 l2cap_emit_le_channel_closed(channel); 2371 } 2372 l2cap_free_channel_entry(channel); 2373 } 2374 #endif 2375 2376 #ifdef ENABLE_CLASSIC 2377 static void l2cap_check_classic_timeout(hci_con_handle_t handle){ 2378 if (gap_get_connection_type(handle) != GAP_CONNECTION_ACL) { 2379 return; 2380 } 2381 if (hci_authentication_active_for_handle(handle)) { 2382 return; 2383 } 2384 bool hci_con_used = false; 2385 btstack_linked_list_iterator_t it; 2386 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2387 while (btstack_linked_list_iterator_has_next(&it)){ 2388 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2389 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2390 if (channel->con_handle != handle) continue; 2391 hci_con_used = true; 2392 break; 2393 } 2394 if (hci_con_used) { 2395 return; 2396 } 2397 if (!hci_can_send_command_packet_now()) { 2398 return; 2399 } 2400 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 2401 } 2402 2403 static void l2cap_handle_features_complete(hci_con_handle_t handle){ 2404 if (hci_remote_features_available(handle) == false){ 2405 return; 2406 } 2407 btstack_linked_list_iterator_t it; 2408 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2409 while (btstack_linked_list_iterator_has_next(&it)){ 2410 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2411 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2412 if (channel->con_handle != handle) continue; 2413 log_info("remote supported features, channel %p, cid %04x - state %u", channel, channel->local_cid, channel->state); 2414 l2cap_handle_remote_supported_features_received(channel); 2415 } 2416 } 2417 2418 static void l2cap_handle_security_level_incoming_sufficient(l2cap_channel_t * channel){ 2419 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2420 // we need to know if ERTM is supported before sending a config response 2421 hci_connection_t * connection = hci_connection_for_handle(channel->con_handle); 2422 if (connection->l2cap_state.information_state != L2CAP_INFORMATION_STATE_DONE){ 2423 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_W2_SEND_EXTENDED_FEATURE_REQUEST; 2424 channel->state = L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES; 2425 return; 2426 } 2427 #endif 2428 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 2429 l2cap_emit_incoming_connection(channel); 2430 } 2431 2432 static void l2cap_handle_security_level(hci_con_handle_t handle, gap_security_level_t actual_level){ 2433 log_info("security level update for handle 0x%04x", handle); 2434 btstack_linked_list_iterator_t it; 2435 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2436 while (btstack_linked_list_iterator_has_next(&it)){ 2437 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2438 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2439 if (channel->con_handle != handle) continue; 2440 2441 gap_security_level_t required_level = channel->required_security_level; 2442 2443 log_info("channel %p, cid %04x - state %u: actual %u >= required %u?", channel, channel->local_cid, channel->state, actual_level, required_level); 2444 2445 switch (channel->state){ 2446 case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE: 2447 if (actual_level >= required_level){ 2448 l2cap_handle_security_level_incoming_sufficient(channel); 2449 } else { 2450 channel->reason = 0x0003; // security block 2451 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2452 } 2453 break; 2454 2455 case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE: 2456 if (actual_level >= required_level){ 2457 l2cap_ready_to_connect(channel); 2458 } else { 2459 // security level insufficient, report error and free channel 2460 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY); 2461 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2462 l2cap_free_channel_entry(channel); 2463 } 2464 break; 2465 2466 default: 2467 break; 2468 } 2469 } 2470 } 2471 #endif 2472 2473 #ifdef L2CAP_USES_CHANNELS 2474 static void l2cap_handle_disconnection_complete(hci_con_handle_t handle){ 2475 // collect channels to close 2476 btstack_linked_list_t channels_to_close = NULL; 2477 btstack_linked_list_iterator_t it; 2478 btstack_linked_list_iterator_init(&it, &l2cap_channels); 2479 while (btstack_linked_list_iterator_has_next(&it)) { 2480 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2481 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 2482 if (channel->con_handle != handle) continue; 2483 btstack_linked_list_iterator_remove(&it); 2484 btstack_linked_list_add(&channels_to_close, (btstack_linked_item_t *) channel); 2485 } 2486 // send l2cap open failed or closed events for all channels on this handle and free them 2487 btstack_linked_list_iterator_init(&it, &channels_to_close); 2488 while (btstack_linked_list_iterator_has_next(&it)) { 2489 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 2490 btstack_linked_list_iterator_remove(&it); 2491 switch(channel->channel_type){ 2492 #ifdef ENABLE_CLASSIC 2493 case L2CAP_CHANNEL_TYPE_CLASSIC: 2494 l2cap_handle_hci_disconnect_event(channel); 2495 break; 2496 #endif 2497 #ifdef ENABLE_LE_DATA_CHANNELS 2498 case L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL: 2499 l2cap_handle_hci_le_disconnect_event(channel); 2500 break; 2501 #endif 2502 default: 2503 break; 2504 } 2505 } 2506 } 2507 #endif 2508 2509 static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t cid, uint8_t *packet, uint16_t size){ 2510 2511 UNUSED(packet_type); // ok: registered with hci_event_callback_registration 2512 UNUSED(cid); // ok: there is no channel 2513 UNUSED(size); // ok: fixed format events read from HCI buffer 2514 2515 #ifdef ENABLE_CLASSIC 2516 bd_addr_t address; 2517 gap_security_level_t security_level; 2518 #endif 2519 #ifdef L2CAP_USES_CHANNELS 2520 hci_con_handle_t handle; 2521 #endif 2522 2523 switch(hci_event_packet_get_type(packet)){ 2524 2525 // Notify channel packet handler if they can send now 2526 case HCI_EVENT_TRANSPORT_PACKET_SENT: 2527 case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS: 2528 case BTSTACK_EVENT_NR_CONNECTIONS_CHANGED: 2529 l2cap_run(); // try sending signaling packets first 2530 l2cap_notify_channel_can_send(); 2531 break; 2532 2533 case HCI_EVENT_COMMAND_STATUS: 2534 #ifdef ENABLE_CLASSIC 2535 // check command status for create connection for errors 2536 if (HCI_EVENT_IS_COMMAND_STATUS(packet, hci_create_connection)){ 2537 // cache outgoing address and reset 2538 (void)memcpy(address, l2cap_outgoing_classic_addr, 6); 2539 memset(l2cap_outgoing_classic_addr, 0, 6); 2540 // error => outgoing connection failed 2541 uint8_t status = hci_event_command_status_get_status(packet); 2542 if (status){ 2543 l2cap_handle_connection_failed_for_addr(address, status); 2544 } 2545 } 2546 #endif 2547 l2cap_run(); // try sending signaling packets first 2548 break; 2549 2550 #ifdef ENABLE_CLASSIC 2551 // handle connection complete events 2552 case HCI_EVENT_CONNECTION_COMPLETE: 2553 reverse_bd_addr(&packet[5], address); 2554 if (packet[2] == 0){ 2555 handle = little_endian_read_16(packet, 3); 2556 l2cap_handle_connection_success_for_addr(address, handle); 2557 } else { 2558 l2cap_handle_connection_failed_for_addr(address, packet[2]); 2559 } 2560 break; 2561 2562 // handle successful create connection cancel command 2563 case HCI_EVENT_COMMAND_COMPLETE: 2564 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_create_connection_cancel)) { 2565 if (packet[5] == 0){ 2566 reverse_bd_addr(&packet[6], address); 2567 // CONNECTION TERMINATED BY LOCAL HOST (0X16) 2568 l2cap_handle_connection_failed_for_addr(address, 0x16); 2569 } 2570 } 2571 l2cap_run(); // try sending signaling packets first 2572 break; 2573 #endif 2574 2575 #ifdef L2CAP_USES_CHANNELS 2576 // handle disconnection complete events 2577 case HCI_EVENT_DISCONNECTION_COMPLETE: 2578 handle = little_endian_read_16(packet, 3); 2579 l2cap_handle_disconnection_complete(handle); 2580 break; 2581 #endif 2582 2583 // HCI Connection Timeouts 2584 #ifdef ENABLE_CLASSIC 2585 case L2CAP_EVENT_TIMEOUT_CHECK: 2586 handle = little_endian_read_16(packet, 2); 2587 l2cap_check_classic_timeout(handle); 2588 break; 2589 2590 case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE: 2591 case HCI_EVENT_READ_REMOTE_EXTENDED_FEATURES_COMPLETE: 2592 handle = little_endian_read_16(packet, 3); 2593 l2cap_handle_features_complete(handle); 2594 break; 2595 2596 case GAP_EVENT_SECURITY_LEVEL: 2597 handle = little_endian_read_16(packet, 2); 2598 security_level = (gap_security_level_t) packet[4]; 2599 l2cap_handle_security_level(handle, security_level); 2600 break; 2601 #endif 2602 default: 2603 break; 2604 } 2605 2606 l2cap_run(); 2607 } 2608 2609 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t cid, uint16_t data){ 2610 // Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused." 2611 if (l2cap_signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) { 2612 l2cap_signaling_responses[l2cap_signaling_responses_pending].handle = handle; 2613 l2cap_signaling_responses[l2cap_signaling_responses_pending].code = code; 2614 l2cap_signaling_responses[l2cap_signaling_responses_pending].sig_id = sig_id; 2615 l2cap_signaling_responses[l2cap_signaling_responses_pending].cid = cid; 2616 l2cap_signaling_responses[l2cap_signaling_responses_pending].data = data; 2617 l2cap_signaling_responses_pending++; 2618 l2cap_run(); 2619 } 2620 } 2621 2622 #ifdef ENABLE_CLASSIC 2623 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){ 2624 switch (channel->state){ 2625 case L2CAP_STATE_CONFIG: 2626 case L2CAP_STATE_OPEN: 2627 case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST: 2628 case L2CAP_STATE_WAIT_DISCONNECT: 2629 break; 2630 default: 2631 // ignore in other states 2632 return; 2633 } 2634 2635 channel->remote_sig_id = identifier; 2636 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 2637 l2cap_run(); 2638 } 2639 2640 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){ 2641 2642 // log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid); 2643 l2cap_service_t *service = l2cap_get_service(psm); 2644 if (!service) { 2645 // 0x0002 PSM not supported 2646 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 2647 return; 2648 } 2649 2650 hci_connection_t * hci_connection = hci_connection_for_handle( handle ); 2651 if (!hci_connection) { 2652 // 2653 log_error("no hci_connection for handle %u", handle); 2654 return; 2655 } 2656 2657 // alloc structure 2658 gap_security_level_t required_level = service->required_security_level; 2659 if (gap_get_secure_connections_only_mode() && (required_level != LEVEL_0)){ 2660 required_level = LEVEL_4; 2661 } 2662 l2cap_channel_t * channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_CLASSIC, hci_connection->address, BD_ADDR_TYPE_ACL, 2663 psm, service->mtu, required_level); 2664 if (!channel){ 2665 // 0x0004 No resources available 2666 l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 2667 return; 2668 } 2669 2670 channel->con_handle = handle; 2671 channel->remote_cid = source_cid; 2672 channel->remote_sig_id = sig_id; 2673 2674 // limit local mtu to max acl packet length - l2cap header 2675 if (channel->local_mtu > l2cap_max_mtu()) { 2676 channel->local_mtu = l2cap_max_mtu(); 2677 } 2678 2679 // set initial state 2680 channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES; 2681 channel->state_var = L2CAP_CHANNEL_STATE_VAR_INCOMING; 2682 2683 // add to connections list 2684 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 2685 2686 // send conn resp pending if remote supported features have not been received yet 2687 if (hci_remote_features_available(handle)) { 2688 l2cap_handle_remote_supported_features_received(channel); 2689 } else { 2690 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND; 2691 hci_remote_features_query(handle); 2692 } 2693 } 2694 2695 void l2cap_accept_connection(uint16_t local_cid){ 2696 log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid); 2697 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 2698 if (!channel) { 2699 log_error("accept called but local_cid 0x%x not found", local_cid); 2700 return; 2701 } 2702 2703 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2704 // configure L2CAP Basic mode 2705 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2706 #endif 2707 2708 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT; 2709 2710 // process 2711 l2cap_run(); 2712 } 2713 2714 void l2cap_decline_connection(uint16_t local_cid){ 2715 log_info("decline local_cid 0x%x", local_cid); 2716 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid); 2717 if (!channel) { 2718 log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid); 2719 return; 2720 } 2721 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE; 2722 channel->reason = 0x04; // no resources available 2723 l2cap_run(); 2724 } 2725 2726 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2727 static void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){ 2728 2729 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2730 uint8_t use_fcs = 1; 2731 #endif 2732 2733 channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2734 2735 uint16_t flags = little_endian_read_16(command, 6); 2736 if (flags & 1) { 2737 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT); 2738 } 2739 2740 // accept the other's configuration options 2741 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2742 uint16_t pos = 8; 2743 while (pos < end_pos){ 2744 uint8_t option_hint = command[pos] >> 7; 2745 uint8_t option_type = command[pos] & 0x7f; 2746 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2747 pos++; 2748 uint8_t length = command[pos++]; 2749 // MTU { type(8): 1, len(8):2, MTU(16) } 2750 if ((option_type == L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT) && (length == 2)){ 2751 channel->remote_mtu = little_endian_read_16(command, pos); 2752 log_info("Remote MTU %u", channel->remote_mtu); 2753 if (channel->remote_mtu > l2cap_max_mtu()){ 2754 log_info("Remote MTU %u larger than outgoing buffer, only using MTU = %u", channel->remote_mtu, l2cap_max_mtu()); 2755 channel->remote_mtu = l2cap_max_mtu(); 2756 } 2757 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU); 2758 } 2759 // Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)} 2760 if ((option_type == L2CAP_CONFIG_OPTION_TYPE_FLUSH_TIMEOUT) && (length == 2)){ 2761 channel->flush_timeout = little_endian_read_16(command, pos); 2762 log_info("Flush timeout: %u ms", channel->flush_timeout); 2763 } 2764 2765 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2766 // Retransmission and Flow Control Option 2767 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2768 l2cap_channel_mode_t mode = (l2cap_channel_mode_t) command[pos]; 2769 switch(channel->mode){ 2770 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2771 // Store remote config 2772 channel->remote_tx_window_size = command[pos+1]; 2773 channel->remote_max_transmit = command[pos+2]; 2774 channel->remote_retransmission_timeout_ms = little_endian_read_16(command, pos + 3); 2775 channel->remote_monitor_timeout_ms = little_endian_read_16(command, pos + 5); 2776 channel->remote_mps = little_endian_read_16(command, pos + 7); 2777 log_info("FC&C config: tx window: %u, max transmit %u, retrans timeout %u, monitor timeout %u, mps %u", 2778 channel->remote_tx_window_size, 2779 channel->remote_max_transmit, 2780 channel->remote_retransmission_timeout_ms, 2781 channel->remote_monitor_timeout_ms, 2782 channel->remote_mps); 2783 // If ERTM mandatory, but remote doens't offer ERTM -> disconnect 2784 if (channel->ertm_mandatory && mode != L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 2785 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2786 } else { 2787 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM); 2788 } 2789 break; 2790 case L2CAP_CHANNEL_MODE_BASIC: 2791 switch (mode){ 2792 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2793 // remote asks for ERTM, but we want basic mode. disconnect if this happens a second time 2794 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED){ 2795 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2796 } 2797 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED); 2798 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED); 2799 break; 2800 default: // case L2CAP_CHANNEL_MODE_BASIC: 2801 // TODO store and evaluate configuration 2802 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM); 2803 break; 2804 } 2805 break; 2806 default: 2807 break; 2808 } 2809 } 2810 if (option_type == L2CAP_CONFIG_OPTION_TYPE_FRAME_CHECK_SEQUENCE && length == 1){ 2811 use_fcs = command[pos]; 2812 } 2813 #endif 2814 // check for unknown options 2815 if ((option_hint == 0) && ((option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT) || (option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE))){ 2816 log_info("l2cap cid %u, unknown option 0x%02x", channel->local_cid, option_type); 2817 channel->unknown_option = option_type; 2818 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2819 } 2820 pos += length; 2821 } 2822 2823 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2824 // "FCS" has precedence over "No FCS" 2825 uint8_t update = channel->fcs_option || use_fcs; 2826 log_info("local fcs: %u, remote fcs: %u -> %u", channel->fcs_option, use_fcs, update); 2827 channel->fcs_option = update; 2828 // If ERTM mandatory, but remote didn't send Retransmission and Flowcontrol options -> disconnect 2829 if (((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM) == 0) & (channel->ertm_mandatory)){ 2830 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2831 } 2832 #endif 2833 } 2834 2835 // @pre command len is valid, see check in l2cap_signaling_handler_channel 2836 static void l2cap_signaling_handle_configure_response(l2cap_channel_t *channel, uint8_t result, uint8_t *command){ 2837 log_info("l2cap_signaling_handle_configure_response"); 2838 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2839 uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2840 uint16_t pos = 10; 2841 while (pos < end_pos){ 2842 uint8_t option_hint = command[pos] >> 7; 2843 uint8_t option_type = command[pos] & 0x7f; 2844 // log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type); 2845 pos++; 2846 uint8_t length = command[pos++]; 2847 2848 // Retransmission and Flow Control Option 2849 if (option_type == L2CAP_CONFIG_OPTION_TYPE_RETRANSMISSION_AND_FLOW_CONTROL && length == 9){ 2850 switch (channel->mode){ 2851 case L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION: 2852 if (channel->ertm_mandatory){ 2853 // ?? 2854 } else { 2855 // On 'Reject - Unacceptable Parameters' to our optional ERTM request, fall back to BASIC mode 2856 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2857 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 2858 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 2859 } 2860 } 2861 break; 2862 case L2CAP_CHANNEL_MODE_BASIC: 2863 if (result == L2CAP_CONF_RESULT_UNACCEPTABLE_PARAMETERS){ 2864 // On 'Reject - Unacceptable Parameters' to our Basic mode request, disconnect 2865 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2866 } 2867 break; 2868 default: 2869 break; 2870 } 2871 } 2872 2873 // check for unknown options 2874 if (option_hint == 0 && (option_type < L2CAP_CONFIG_OPTION_TYPE_MAX_TRANSMISSION_UNIT || option_type > L2CAP_CONFIG_OPTION_TYPE_EXTENDED_WINDOW_SIZE)){ 2875 log_info("l2cap cid %u, unknown option 0x%02x", channel->local_cid, option_type); 2876 channel->unknown_option = option_type; 2877 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID); 2878 } 2879 2880 pos += length; 2881 } 2882 #else 2883 UNUSED(channel); // ok: no code 2884 UNUSED(result); // ok: no code 2885 UNUSED(command); // ok: no code 2886 #endif 2887 } 2888 2889 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){ 2890 // log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var); 2891 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0; 2892 if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0; 2893 // addition check that fixes re-entrance issue causing l2cap event channel opened twice 2894 if (channel->state == L2CAP_STATE_OPEN) return 0; 2895 return 1; 2896 } 2897 2898 2899 // @pre command len is valid, see check in l2cap_signaling_handler_dispatch 2900 static void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){ 2901 2902 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 2903 uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 2904 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 2905 uint16_t result = 0; 2906 2907 log_info("L2CAP signaling handler code %u, state %u", code, channel->state); 2908 2909 // handle DISCONNECT REQUESTS seperately 2910 if (code == DISCONNECTION_REQUEST){ 2911 l2cap_handle_disconnect_request(channel, identifier); 2912 return; 2913 } 2914 2915 // @STATEMACHINE(l2cap) 2916 switch (channel->state) { 2917 2918 case L2CAP_STATE_WAIT_CONNECT_RSP: 2919 switch (code){ 2920 case CONNECTION_RESPONSE: 2921 if (cmd_len < 8){ 2922 // command imcomplete 2923 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2924 break; 2925 } 2926 l2cap_stop_rtx(channel); 2927 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2928 switch (result) { 2929 case 0: 2930 // successful connection 2931 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 2932 channel->state = L2CAP_STATE_CONFIG; 2933 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 2934 break; 2935 case 1: 2936 // connection pending. get some coffee, but start the ERTX 2937 l2cap_start_ertx(channel); 2938 break; 2939 default: 2940 // channel closed 2941 channel->state = L2CAP_STATE_CLOSED; 2942 // map l2cap connection response result to BTstack status enumeration 2943 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result); 2944 2945 // drop link key if security block 2946 if ((L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result) == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){ 2947 gap_drop_link_key_for_bd_addr(channel->address); 2948 } 2949 2950 // discard channel 2951 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 2952 l2cap_free_channel_entry(channel); 2953 break; 2954 } 2955 break; 2956 2957 default: 2958 //@TODO: implement other signaling packets 2959 break; 2960 } 2961 break; 2962 2963 case L2CAP_STATE_CONFIG: 2964 switch (code) { 2965 case CONFIGURE_REQUEST: 2966 if (cmd_len < 4){ 2967 // command incomplete 2968 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2969 break; 2970 } 2971 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP); 2972 l2cap_signaling_handle_configure_request(channel, command); 2973 if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){ 2974 // only done if continuation not set 2975 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ); 2976 } 2977 break; 2978 case CONFIGURE_RESPONSE: 2979 if (cmd_len < 6){ 2980 // command incomplete 2981 l2cap_register_signaling_response(channel->con_handle, COMMAND_REJECT, identifier, 0, L2CAP_REJ_CMD_UNKNOWN); 2982 break; 2983 } 2984 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 2985 l2cap_stop_rtx(channel); 2986 l2cap_signaling_handle_configure_response(channel, result, command); 2987 switch (result){ 2988 case 0: // success 2989 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP); 2990 break; 2991 case 4: // pending 2992 l2cap_start_ertx(channel); 2993 break; 2994 default: 2995 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 2996 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION && channel->ertm_mandatory){ 2997 // remote does not offer ertm but it's required 2998 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 2999 break; 3000 } 3001 #endif 3002 // retry on negative result 3003 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ); 3004 break; 3005 } 3006 break; 3007 default: 3008 break; 3009 } 3010 if (l2cap_channel_ready_for_open(channel)){ 3011 3012 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3013 // assert that packet can be stored in fragment buffers in ertm 3014 if (channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 3015 uint16_t effective_mps = btstack_min(channel->remote_mps, channel->local_mps); 3016 uint16_t usable_mtu = channel->num_tx_buffers == 1 ? effective_mps : channel->num_tx_buffers * effective_mps - 2; 3017 if (usable_mtu < channel->remote_mtu){ 3018 log_info("Remote MTU %u > max storable ERTM packet, only using MTU = %u", channel->remote_mtu, usable_mtu); 3019 channel->remote_mtu = usable_mtu; 3020 } 3021 } 3022 #endif 3023 // for open: 3024 channel->state = L2CAP_STATE_OPEN; 3025 l2cap_emit_channel_opened(channel, 0); 3026 } 3027 break; 3028 3029 case L2CAP_STATE_WAIT_DISCONNECT: 3030 switch (code) { 3031 case DISCONNECTION_RESPONSE: 3032 l2cap_finialize_channel_close(channel); 3033 break; 3034 default: 3035 //@TODO: implement other signaling packets 3036 break; 3037 } 3038 break; 3039 3040 case L2CAP_STATE_CLOSED: 3041 // @TODO handle incoming requests 3042 break; 3043 3044 case L2CAP_STATE_OPEN: 3045 //@TODO: implement other signaling packets, e.g. re-configure 3046 break; 3047 default: 3048 break; 3049 } 3050 // log_info("new state %u", channel->state); 3051 } 3052 3053 3054 // @pre command len is valid, see check in l2cap_acl_classic_handler 3055 static void l2cap_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command){ 3056 3057 btstack_linked_list_iterator_t it; 3058 3059 // get code, signalind identifier and command len 3060 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 3061 uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET]; 3062 uint16_t cmd_len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3063 3064 // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_RESPONSE 3065 if ((code < 1) || (code == ECHO_RESPONSE) || (code > INFORMATION_RESPONSE)){ 3066 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3067 return; 3068 } 3069 3070 // general commands without an assigned channel 3071 switch(code) { 3072 3073 case CONNECTION_REQUEST: 3074 if (cmd_len == 4){ 3075 uint16_t psm = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3076 uint16_t source_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3077 l2cap_handle_connection_request(handle, sig_id, psm, source_cid); 3078 } else { 3079 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3080 } 3081 return; 3082 3083 case ECHO_REQUEST: 3084 l2cap_register_signaling_response(handle, code, sig_id, 0, 0); 3085 return; 3086 3087 case INFORMATION_REQUEST: 3088 if (cmd_len == 2) { 3089 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3090 l2cap_register_signaling_response(handle, code, sig_id, 0, info_type); 3091 } else { 3092 l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3093 } 3094 return; 3095 3096 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3097 case INFORMATION_RESPONSE: { 3098 hci_connection_t * connection = hci_connection_for_handle(handle); 3099 if (!connection) return; 3100 if (connection->l2cap_state.information_state != L2CAP_INFORMATION_STATE_W4_EXTENDED_FEATURE_RESPONSE) return; 3101 3102 // get extended features from response if valid 3103 connection->l2cap_state.extended_feature_mask = 0; 3104 if (cmd_len >= 6) { 3105 uint16_t info_type = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3106 uint16_t result = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3107 if (result == 0 && info_type == L2CAP_INFO_TYPE_EXTENDED_FEATURES_SUPPORTED) { 3108 connection->l2cap_state.extended_feature_mask = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 3109 } 3110 } 3111 connection->l2cap_state.information_state = L2CAP_INFORMATION_STATE_DONE; 3112 log_info("extended features mask 0x%02x", connection->l2cap_state.extended_feature_mask); 3113 3114 // trigger connection request 3115 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3116 while (btstack_linked_list_iterator_has_next(&it)){ 3117 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3118 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 3119 if (channel->con_handle != handle) continue; 3120 3121 // incoming connection: ask user for channel configuration, esp. if ertm will be mandatory 3122 if (channel->state == L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES){ 3123 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 3124 l2cap_emit_incoming_connection(channel); 3125 continue; 3126 } 3127 3128 // outgoing connection 3129 if (channel->state == L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES){ 3130 3131 // if ERTM was requested, but is not listed in extended feature mask: 3132 if ((channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION) && ((connection->l2cap_state.extended_feature_mask & 0x08) == 0)){ 3133 3134 if (channel->ertm_mandatory){ 3135 // bail if ERTM is mandatory 3136 channel->state = L2CAP_STATE_CLOSED; 3137 // map l2cap connection response result to BTstack status enumeration 3138 l2cap_handle_channel_open_failed(channel, L2CAP_CONNECTION_RESPONSE_RESULT_ERTM_NOT_SUPPORTED); 3139 // discard channel 3140 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3141 l2cap_free_channel_entry(channel); 3142 continue; 3143 3144 } else { 3145 // fallback to Basic mode 3146 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_ERTM_BUFFER_RELEASED); 3147 channel->mode = L2CAP_CHANNEL_MODE_BASIC; 3148 } 3149 } 3150 3151 // respond to connection request 3152 channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST; 3153 continue; 3154 } 3155 } 3156 return; 3157 } 3158 #endif 3159 3160 default: 3161 break; 3162 } 3163 3164 // Get potential destination CID 3165 uint16_t dest_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3166 3167 // Find channel for this sig_id and connection handle 3168 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3169 while (btstack_linked_list_iterator_has_next(&it)){ 3170 l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3171 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 3172 if (channel->con_handle != handle) continue; 3173 if (code & 1) { 3174 // match odd commands (responses) by previous signaling identifier 3175 if (channel->local_sig_id == sig_id) { 3176 l2cap_signaling_handler_channel(channel, command); 3177 break; 3178 } 3179 } else { 3180 // match even commands (requests) by local channel id 3181 if (channel->local_cid == dest_cid) { 3182 l2cap_signaling_handler_channel(channel, command); 3183 break; 3184 } 3185 } 3186 } 3187 } 3188 #endif 3189 3190 #ifdef ENABLE_BLE 3191 3192 static void l2cap_emit_connection_parameter_update_response(hci_con_handle_t con_handle, uint16_t result){ 3193 uint8_t event[6]; 3194 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE; 3195 event[1] = 4; 3196 little_endian_store_16(event, 2, con_handle); 3197 little_endian_store_16(event, 4, result); 3198 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3199 if (!l2cap_event_packet_handler) return; 3200 (*l2cap_event_packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event)); 3201 } 3202 3203 // @returns valid 3204 static int l2cap_le_signaling_handler_dispatch(hci_con_handle_t handle, uint8_t * command, uint8_t sig_id){ 3205 hci_connection_t * connection; 3206 uint16_t result; 3207 uint8_t event[12]; 3208 3209 #ifdef ENABLE_LE_DATA_CHANNELS 3210 btstack_linked_list_iterator_t it; 3211 l2cap_channel_t * channel; 3212 uint16_t local_cid; 3213 uint16_t le_psm; 3214 uint16_t new_credits; 3215 uint16_t credits_before; 3216 l2cap_service_t * service; 3217 uint16_t source_cid; 3218 #endif 3219 3220 uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET]; 3221 uint16_t len = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3222 log_info("le dispatch: command 0x%02x, sig id %u, len %u", code, sig_id, len); 3223 3224 switch (code){ 3225 3226 case CONNECTION_PARAMETER_UPDATE_REQUEST: 3227 // check size 3228 if (len < 8u) return 0u; 3229 connection = hci_connection_for_handle(handle); 3230 if (connection != NULL){ 3231 if (connection->role != HCI_ROLE_MASTER){ 3232 // reject command without notifying upper layer when not in master role 3233 return 0; 3234 } 3235 le_connection_parameter_range_t existing_range; 3236 gap_get_connection_parameter_range(&existing_range); 3237 uint16_t le_conn_interval_min = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET); 3238 uint16_t le_conn_interval_max = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2); 3239 uint16_t le_conn_latency = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4); 3240 uint16_t le_supervision_timeout = little_endian_read_16(command,L2CAP_SIGNALING_COMMAND_DATA_OFFSET+6); 3241 3242 int update_parameter = gap_connection_parameter_range_included(&existing_range, le_conn_interval_min, le_conn_interval_max, le_conn_latency, le_supervision_timeout); 3243 if (update_parameter){ 3244 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE; 3245 connection->le_conn_interval_min = le_conn_interval_min; 3246 connection->le_conn_interval_max = le_conn_interval_max; 3247 connection->le_conn_latency = le_conn_latency; 3248 connection->le_supervision_timeout = le_supervision_timeout; 3249 } else { 3250 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY; 3251 } 3252 connection->le_con_param_update_identifier = sig_id; 3253 } 3254 3255 if (!l2cap_event_packet_handler) break; 3256 3257 event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST; 3258 event[1] = 8; 3259 little_endian_store_16(event, 2, handle); 3260 (void)memcpy(&event[4], &command[4], 8); 3261 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3262 (*l2cap_event_packet_handler)( HCI_EVENT_PACKET, 0, event, sizeof(event)); 3263 break; 3264 3265 case CONNECTION_PARAMETER_UPDATE_RESPONSE: 3266 // check size 3267 if (len < 2u) return 0u; 3268 result = little_endian_read_16(command, 4); 3269 l2cap_emit_connection_parameter_update_response(handle, result); 3270 break; 3271 3272 #ifdef ENABLE_LE_DATA_CHANNELS 3273 3274 case COMMAND_REJECT: 3275 // Find channel for this sig_id and connection handle 3276 channel = NULL; 3277 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3278 while (btstack_linked_list_iterator_has_next(&it)){ 3279 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3280 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3281 if (a_channel->con_handle != handle) continue; 3282 if (a_channel->local_sig_id != sig_id) continue; 3283 channel = a_channel; 3284 break; 3285 } 3286 if (!channel) break; 3287 3288 // if received while waiting for le connection response, assume legacy device 3289 if (channel->state == L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE){ 3290 channel->state = L2CAP_STATE_CLOSED; 3291 // no official value for this, use: Connection refused – LE_PSM not supported - 0x0002 3292 l2cap_emit_le_channel_opened(channel, 0x0002); 3293 3294 // discard channel 3295 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3296 l2cap_free_channel_entry(channel); 3297 break; 3298 } 3299 break; 3300 3301 case LE_CREDIT_BASED_CONNECTION_REQUEST: 3302 // check size 3303 if (len < 10u) return 0u; 3304 3305 // get hci connection, bail if not found (must not happen) 3306 connection = hci_connection_for_handle(handle); 3307 if (!connection) return 0; 3308 3309 // check if service registered 3310 le_psm = little_endian_read_16(command, 4); 3311 service = l2cap_le_get_service(le_psm); 3312 source_cid = little_endian_read_16(command, 6); 3313 3314 if (service){ 3315 if (source_cid < 0x40u){ 3316 // 0x0009 Connection refused - Invalid Source CID 3317 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0009); 3318 return 1; 3319 } 3320 3321 // go through list of channels for this ACL connection and check if we get a match 3322 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3323 while (btstack_linked_list_iterator_has_next(&it)){ 3324 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3325 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3326 if (a_channel->con_handle != handle) continue; 3327 if (a_channel->remote_cid != source_cid) continue; 3328 // 0x000a Connection refused - Source CID already allocated 3329 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x000a); 3330 return 1; 3331 } 3332 3333 // security: check encryption 3334 if (service->required_security_level >= LEVEL_2){ 3335 if (gap_encryption_key_size(handle) == 0){ 3336 // 0x0008 Connection refused - insufficient encryption 3337 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0008); 3338 return 1; 3339 } 3340 // anything less than 16 byte key size is insufficient 3341 if (gap_encryption_key_size(handle) < 16){ 3342 // 0x0007 Connection refused – insufficient encryption key size 3343 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0007); 3344 return 1; 3345 } 3346 } 3347 3348 // security: check authencation 3349 if (service->required_security_level >= LEVEL_3){ 3350 if (!gap_authenticated(handle)){ 3351 // 0x0005 Connection refused – insufficient authentication 3352 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0005); 3353 return 1; 3354 } 3355 } 3356 3357 // security: check authorization 3358 if (service->required_security_level >= LEVEL_4){ 3359 if (gap_authorization_state(handle) != AUTHORIZATION_GRANTED){ 3360 // 0x0006 Connection refused – insufficient authorization 3361 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0006); 3362 return 1; 3363 } 3364 } 3365 3366 // allocate channel 3367 channel = l2cap_create_channel_entry(service->packet_handler, L2CAP_CHANNEL_TYPE_LE_DATA_CHANNEL, connection->address, 3368 BD_ADDR_TYPE_LE_RANDOM, le_psm, service->mtu, service->required_security_level); 3369 if (!channel){ 3370 // 0x0004 Connection refused – no resources available 3371 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0004); 3372 return 1; 3373 } 3374 3375 channel->con_handle = handle; 3376 channel->remote_cid = source_cid; 3377 channel->remote_sig_id = sig_id; 3378 channel->remote_mtu = little_endian_read_16(command, 8); 3379 channel->remote_mps = little_endian_read_16(command, 10); 3380 channel->credits_outgoing = little_endian_read_16(command, 12); 3381 3382 // set initial state 3383 channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT; 3384 channel->state_var |= L2CAP_CHANNEL_STATE_VAR_INCOMING; 3385 3386 // add to connections list 3387 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 3388 3389 // post connection request event 3390 l2cap_emit_le_incoming_connection(channel); 3391 3392 } else { 3393 // Connection refused – LE_PSM not supported 3394 l2cap_register_signaling_response(handle, LE_CREDIT_BASED_CONNECTION_REQUEST, sig_id, source_cid, 0x0002); 3395 } 3396 break; 3397 3398 case LE_CREDIT_BASED_CONNECTION_RESPONSE: 3399 // check size 3400 if (len < 10u) return 0u; 3401 3402 // Find channel for this sig_id and connection handle 3403 channel = NULL; 3404 btstack_linked_list_iterator_init(&it, &l2cap_channels); 3405 while (btstack_linked_list_iterator_has_next(&it)){ 3406 l2cap_channel_t * a_channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 3407 if (!l2cap_is_dynamic_channel_type(a_channel->channel_type)) continue; 3408 if (a_channel->con_handle != handle) continue; 3409 if (a_channel->local_sig_id != sig_id) continue; 3410 channel = a_channel; 3411 break; 3412 } 3413 if (!channel) break; 3414 3415 // cid + 0 3416 result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+8); 3417 if (result){ 3418 channel->state = L2CAP_STATE_CLOSED; 3419 // map l2cap connection response result to BTstack status enumeration 3420 l2cap_emit_le_channel_opened(channel, result); 3421 3422 // discard channel 3423 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3424 l2cap_free_channel_entry(channel); 3425 break; 3426 } 3427 3428 // success 3429 channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3430 channel->remote_mtu = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 3431 channel->remote_mps = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 4); 3432 channel->credits_outgoing = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 6); 3433 channel->state = L2CAP_STATE_OPEN; 3434 l2cap_emit_le_channel_opened(channel, result); 3435 break; 3436 3437 case LE_FLOW_CONTROL_CREDIT: 3438 // check size 3439 if (len < 4u) return 0u; 3440 3441 // find channel 3442 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3443 channel = l2cap_get_channel_for_local_cid_and_handle(local_cid, handle); 3444 if (!channel) { 3445 log_error("credit: no channel for cid 0x%02x", local_cid); 3446 break; 3447 } 3448 new_credits = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 2); 3449 credits_before = channel->credits_outgoing; 3450 channel->credits_outgoing += new_credits; 3451 // check for credit overrun 3452 if (credits_before > channel->credits_outgoing){ 3453 log_error("credit: new credits caused overrrun for cid 0x%02x, disconnecting", local_cid); 3454 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3455 break; 3456 } 3457 log_info("credit: %u credits for 0x%02x, now %u", new_credits, local_cid, channel->credits_outgoing); 3458 break; 3459 3460 case DISCONNECTION_REQUEST: 3461 3462 // check size 3463 if (len < 4u) return 0u; 3464 3465 // find channel 3466 local_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET + 0); 3467 channel = l2cap_get_channel_for_local_cid_and_handle(local_cid, handle); 3468 if (!channel) { 3469 log_error("credit: no channel for cid 0x%02x", local_cid); 3470 break; 3471 } 3472 channel->remote_sig_id = sig_id; 3473 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE; 3474 break; 3475 3476 #endif 3477 3478 case DISCONNECTION_RESPONSE: 3479 break; 3480 3481 default: 3482 // command unknown -> reject command 3483 return 0; 3484 } 3485 return 1; 3486 } 3487 #endif 3488 3489 #ifdef ENABLE_CLASSIC 3490 static void l2cap_acl_classic_handler_for_channel(l2cap_channel_t * l2cap_channel, uint8_t * packet, uint16_t size){ 3491 3492 // forward data only in OPEN state 3493 if (l2cap_channel->state != L2CAP_STATE_OPEN) return; 3494 3495 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE 3496 if (l2cap_channel->mode == L2CAP_CHANNEL_MODE_ENHANCED_RETRANSMISSION){ 3497 3498 int fcs_size = l2cap_channel->fcs_option ? 2 : 0; 3499 3500 // assert control + FCS fields are inside 3501 if (size < COMPLETE_L2CAP_HEADER+2+fcs_size) return; 3502 3503 if (l2cap_channel->fcs_option){ 3504 // verify FCS (required if one side requested it) 3505 uint16_t fcs_calculated = crc16_calc(&packet[4], size - (4+2)); 3506 uint16_t fcs_packet = little_endian_read_16(packet, size-2); 3507 3508 #ifdef L2CAP_ERTM_SIMULATE_FCS_ERROR_INTERVAL 3509 // simulate fcs error 3510 static int counter = 0; 3511 if (++counter == L2CAP_ERTM_SIMULATE_FCS_ERROR_INTERVAL) { 3512 log_info("Simulate fcs error"); 3513 fcs_calculated++; 3514 counter = 0; 3515 } 3516 #endif 3517 3518 if (fcs_calculated == fcs_packet){ 3519 log_info("Packet FCS 0x%04x verified", fcs_packet); 3520 } else { 3521 log_error("FCS mismatch! Packet 0x%04x, calculated 0x%04x", fcs_packet, fcs_calculated); 3522 // ERTM State Machine in Bluetooth Spec does not handle 'I-Frame with invalid FCS' 3523 return; 3524 } 3525 } 3526 3527 // switch on packet type 3528 uint16_t control = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3529 uint8_t req_seq = (control >> 8) & 0x3f; 3530 int final = (control >> 7) & 0x01; 3531 if (control & 1){ 3532 // S-Frame 3533 int poll = (control >> 4) & 0x01; 3534 l2cap_supervisory_function_t s = (l2cap_supervisory_function_t) ((control >> 2) & 0x03); 3535 log_info("Control: 0x%04x => Supervisory function %u, ReqSeq %02u", control, (int) s, req_seq); 3536 l2cap_ertm_tx_packet_state_t * tx_state; 3537 switch (s){ 3538 case L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY: 3539 log_info("L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY"); 3540 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3541 if (poll && final){ 3542 // S-frames shall not be transmitted with both the F-bit and the P-bit set to 1 at the same time. 3543 log_error("P=F=1 in S-Frame"); 3544 break; 3545 } 3546 if (poll){ 3547 // check if we did request selective retransmission before <==> we have stored SDU segments 3548 int i; 3549 int num_stored_out_of_order_packets = 0; 3550 for (i=0;i<l2cap_channel->num_rx_buffers;i++){ 3551 int index = l2cap_channel->rx_store_index + i; 3552 if (index >= l2cap_channel->num_rx_buffers){ 3553 index -= l2cap_channel->num_rx_buffers; 3554 } 3555 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3556 if (!rx_state->valid) continue; 3557 num_stored_out_of_order_packets++; 3558 } 3559 if (num_stored_out_of_order_packets){ 3560 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3561 } else { 3562 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3563 } 3564 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = 1; 3565 } 3566 if (final){ 3567 // Stop-MonitorTimer 3568 l2cap_ertm_stop_monitor_timer(l2cap_channel); 3569 // If UnackedFrames > 0 then Start-RetransTimer 3570 if (l2cap_channel->unacked_frames){ 3571 l2cap_ertm_start_retransmission_timer(l2cap_channel); 3572 } 3573 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3574 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3575 } 3576 break; 3577 case L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT: 3578 log_info("L2CAP_SUPERVISORY_FUNCTION_REJ_REJECT"); 3579 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3580 // restart transmittion from last unacknowledted packet (earlier packets already freed in l2cap_ertm_process_req_seq) 3581 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3582 break; 3583 case L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY: 3584 log_error("L2CAP_SUPERVISORY_FUNCTION_RNR_RECEIVER_NOT_READY"); 3585 break; 3586 case L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT: 3587 log_info("L2CAP_SUPERVISORY_FUNCTION_SREJ_SELECTIVE_REJECT"); 3588 if (poll){ 3589 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3590 } 3591 // find requested i-frame 3592 tx_state = l2cap_ertm_get_tx_state(l2cap_channel, req_seq); 3593 if (tx_state){ 3594 log_info("Retransmission for tx_seq %u requested", req_seq); 3595 l2cap_channel->set_final_bit_after_packet_with_poll_bit_set = poll; 3596 tx_state->retransmission_requested = 1; 3597 l2cap_channel->srej_active = 1; 3598 } 3599 break; 3600 default: 3601 break; 3602 } 3603 } else { 3604 // I-Frame 3605 // get control 3606 l2cap_segmentation_and_reassembly_t sar = (l2cap_segmentation_and_reassembly_t) (control >> 14); 3607 uint8_t tx_seq = (control >> 1) & 0x3f; 3608 log_info("Control: 0x%04x => SAR %u, ReqSeq %02u, R?, TxSeq %02u", control, (int) sar, req_seq, tx_seq); 3609 log_info("SAR: pos %u", l2cap_channel->reassembly_pos); 3610 log_info("State: expected_tx_seq %02u, req_seq %02u", l2cap_channel->expected_tx_seq, l2cap_channel->req_seq); 3611 l2cap_ertm_process_req_seq(l2cap_channel, req_seq); 3612 if (final){ 3613 // final bit set <- response to RR with poll bit set. All not acknowledged packets need to be retransmitted 3614 l2cap_ertm_retransmit_unacknowleded_frames(l2cap_channel); 3615 } 3616 3617 // get SDU 3618 const uint8_t * payload_data = &packet[COMPLETE_L2CAP_HEADER+2]; 3619 uint16_t payload_len = size-(COMPLETE_L2CAP_HEADER+2+fcs_size); 3620 3621 // assert SDU size is smaller or equal to our buffers 3622 uint16_t max_payload_size = 0; 3623 switch (sar){ 3624 case L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU: 3625 case L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU: 3626 // SDU Length + MPS 3627 max_payload_size = l2cap_channel->local_mps + 2; 3628 break; 3629 case L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU: 3630 case L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU: 3631 max_payload_size = l2cap_channel->local_mps; 3632 break; 3633 default: 3634 btstack_assert(false); 3635 break; 3636 } 3637 if (payload_len > max_payload_size){ 3638 log_info("payload len %u > max payload %u -> drop packet", payload_len, max_payload_size); 3639 return; 3640 } 3641 3642 // check ordering 3643 if (l2cap_channel->expected_tx_seq == tx_seq){ 3644 log_info("Received expected frame with TxSeq == ExpectedTxSeq == %02u", tx_seq); 3645 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3646 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3647 3648 // process SDU 3649 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, sar, payload_data, payload_len); 3650 3651 // process stored segments 3652 while (true){ 3653 int index = l2cap_channel->rx_store_index; 3654 l2cap_ertm_rx_packet_state_t * rx_state = &l2cap_channel->rx_packets_state[index]; 3655 if (!rx_state->valid) break; 3656 3657 log_info("Processing stored frame with TxSeq == ExpectedTxSeq == %02u", l2cap_channel->expected_tx_seq); 3658 l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq); 3659 l2cap_channel->req_seq = l2cap_channel->expected_tx_seq; 3660 3661 rx_state->valid = 0; 3662 l2cap_ertm_handle_in_sequence_sdu(l2cap_channel, rx_state->sar, &l2cap_channel->rx_packets_data[index], rx_state->len); 3663 3664 // update rx store index 3665 index++; 3666 if (index >= l2cap_channel->num_rx_buffers){ 3667 index = 0; 3668 } 3669 l2cap_channel->rx_store_index = index; 3670 } 3671 3672 // 3673 l2cap_channel->send_supervisor_frame_receiver_ready = 1; 3674 3675 } else { 3676 int delta = (tx_seq - l2cap_channel->expected_tx_seq) & 0x3f; 3677 if (delta < 2){ 3678 // store segment 3679 l2cap_ertm_handle_out_of_sequence_sdu(l2cap_channel, sar, delta, payload_data, payload_len); 3680 3681 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-SREJ", tx_seq, l2cap_channel->expected_tx_seq); 3682 l2cap_channel->send_supervisor_frame_selective_reject = 1; 3683 } else { 3684 log_info("Received unexpected frame TxSeq %u but expected %u -> send S-REJ", tx_seq, l2cap_channel->expected_tx_seq); 3685 l2cap_channel->send_supervisor_frame_reject = 1; 3686 } 3687 } 3688 } 3689 return; 3690 } 3691 #endif 3692 3693 // check size 3694 uint16_t payload_size = size - COMPLETE_L2CAP_HEADER; 3695 if (l2cap_channel->local_mtu < payload_size) return; 3696 3697 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], payload_size); 3698 } 3699 #endif 3700 3701 static void l2cap_acl_classic_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3702 #ifdef ENABLE_CLASSIC 3703 l2cap_channel_t * l2cap_channel; 3704 l2cap_fixed_channel_t * l2cap_fixed_channel; 3705 3706 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3707 uint8_t broadcast_flag = READ_ACL_FLAGS(packet) >> 2; 3708 switch (channel_id) { 3709 3710 case L2CAP_CID_SIGNALING: { 3711 if (broadcast_flag != 0) break; 3712 uint32_t command_offset = 8; 3713 while ((command_offset + L2CAP_SIGNALING_COMMAND_DATA_OFFSET) < size) { 3714 // assert signaling command is fully inside packet 3715 uint16_t data_len = little_endian_read_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET); 3716 uint32_t next_command_offset = command_offset + L2CAP_SIGNALING_COMMAND_DATA_OFFSET + data_len; 3717 if (next_command_offset > size){ 3718 log_error("l2cap signaling command len invalid -> drop"); 3719 break; 3720 } 3721 // handle signaling command 3722 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]); 3723 // go to next command 3724 command_offset = next_command_offset; 3725 } 3726 break; 3727 } 3728 3729 case L2CAP_CID_CONNECTIONLESS_CHANNEL: 3730 if (broadcast_flag == 0) break; 3731 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_CONNECTIONLESS_CHANNEL); 3732 if (!l2cap_fixed_channel) break; 3733 if (!l2cap_fixed_channel->packet_handler) break; 3734 (*l2cap_fixed_channel->packet_handler)(UCD_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3735 break; 3736 3737 #ifdef ENABLE_BLE 3738 case L2CAP_CID_BR_EDR_SECURITY_MANAGER: 3739 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3740 if ((l2cap_fixed_channel == NULL) || (l2cap_fixed_channel->packet_handler == NULL)){ 3741 // Pairing Failed 3742 l2cap_register_signaling_response(handle, (uint8_t) SM_PAIRING_FAILED, 0, L2CAP_CID_BR_EDR_SECURITY_MANAGER, SM_REASON_PAIRING_NOT_SUPPORTED); 3743 } else { 3744 (*l2cap_fixed_channel->packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3745 } 3746 break; 3747 #endif 3748 3749 default: 3750 if (broadcast_flag != 0) break; 3751 // Find channel for this channel_id and connection handle 3752 l2cap_channel = l2cap_get_channel_for_local_cid_and_handle(channel_id, handle); 3753 if (l2cap_channel != NULL){ 3754 l2cap_acl_classic_handler_for_channel(l2cap_channel, packet, size); 3755 } 3756 break; 3757 } 3758 #else 3759 UNUSED(handle); // ok: no code 3760 UNUSED(packet); // ok: no code 3761 UNUSED(size); // ok: no code 3762 #endif 3763 } 3764 3765 static void l2cap_acl_le_handler(hci_con_handle_t handle, uint8_t *packet, uint16_t size){ 3766 #ifdef ENABLE_BLE 3767 3768 l2cap_fixed_channel_t * l2cap_fixed_channel; 3769 3770 #ifdef ENABLE_LE_DATA_CHANNELS 3771 l2cap_channel_t * l2cap_channel; 3772 #endif 3773 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 3774 switch (channel_id) { 3775 3776 case L2CAP_CID_SIGNALING_LE: { 3777 uint16_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1]; 3778 uint16_t len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER + 2); 3779 if ((COMPLETE_L2CAP_HEADER + 4u + len) > size) break; 3780 int valid = l2cap_le_signaling_handler_dispatch(handle, &packet[COMPLETE_L2CAP_HEADER], sig_id); 3781 if (!valid){ 3782 l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, 0, L2CAP_REJ_CMD_UNKNOWN); 3783 } 3784 break; 3785 } 3786 3787 case L2CAP_CID_ATTRIBUTE_PROTOCOL: 3788 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_ATTRIBUTE_PROTOCOL); 3789 if (!l2cap_fixed_channel) break; 3790 if (!l2cap_fixed_channel->packet_handler) break; 3791 (*l2cap_fixed_channel->packet_handler)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3792 break; 3793 3794 case L2CAP_CID_SECURITY_MANAGER_PROTOCOL: 3795 l2cap_fixed_channel = l2cap_fixed_channel_for_channel_id(L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3796 if ((l2cap_fixed_channel == NULL) || (l2cap_fixed_channel->packet_handler == NULL)){ 3797 // Pairing Failed 3798 l2cap_register_signaling_response(handle, (uint8_t) SM_PAIRING_FAILED, 0, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, SM_REASON_PAIRING_NOT_SUPPORTED); 3799 } else { 3800 (*l2cap_fixed_channel->packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER); 3801 } 3802 break; 3803 3804 default: 3805 3806 #ifdef ENABLE_LE_DATA_CHANNELS 3807 l2cap_channel = l2cap_get_channel_for_local_cid_and_handle(channel_id, handle); 3808 if (l2cap_channel != NULL) { 3809 // credit counting 3810 if (l2cap_channel->credits_incoming == 0u){ 3811 log_info("LE Data Channel packet received but no incoming credits"); 3812 l2cap_channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 3813 break; 3814 } 3815 l2cap_channel->credits_incoming--; 3816 3817 // automatic credits 3818 if ((l2cap_channel->credits_incoming < L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_WATERMARK) && l2cap_channel->automatic_credits){ 3819 l2cap_channel->new_credits_incoming = L2CAP_LE_DATA_CHANNELS_AUTOMATIC_CREDITS_INCREMENT; 3820 } 3821 3822 // first fragment 3823 uint16_t pos = 0; 3824 if (!l2cap_channel->receive_sdu_len){ 3825 uint16_t sdu_len = little_endian_read_16(packet, COMPLETE_L2CAP_HEADER); 3826 if(sdu_len > l2cap_channel->local_mtu) break; // SDU would be larger than our buffer 3827 l2cap_channel->receive_sdu_len = sdu_len; 3828 l2cap_channel->receive_sdu_pos = 0; 3829 pos += 2u; 3830 size -= 2u; 3831 } 3832 uint16_t fragment_size = size-COMPLETE_L2CAP_HEADER; 3833 uint16_t remaining_space = l2cap_channel->local_mtu - l2cap_channel->receive_sdu_pos; 3834 if (fragment_size > remaining_space) break; // SDU would cause buffer overrun 3835 (void)memcpy(&l2cap_channel->receive_sdu_buffer[l2cap_channel->receive_sdu_pos], 3836 &packet[COMPLETE_L2CAP_HEADER + pos], 3837 fragment_size); 3838 l2cap_channel->receive_sdu_pos += size - COMPLETE_L2CAP_HEADER; 3839 // done? 3840 log_debug("le packet pos %u, len %u", l2cap_channel->receive_sdu_pos, l2cap_channel->receive_sdu_len); 3841 if (l2cap_channel->receive_sdu_pos >= l2cap_channel->receive_sdu_len){ 3842 l2cap_dispatch_to_channel(l2cap_channel, L2CAP_DATA_PACKET, l2cap_channel->receive_sdu_buffer, l2cap_channel->receive_sdu_len); 3843 l2cap_channel->receive_sdu_len = 0; 3844 } 3845 } 3846 #endif 3847 break; 3848 } 3849 #else 3850 UNUSED(handle); // ok: no code 3851 UNUSED(packet); // ok: no code 3852 UNUSED(size); // ok: no code 3853 #endif 3854 } 3855 3856 static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3857 UNUSED(packet_type); // ok: registered with hci_register_acl_packet_handler 3858 UNUSED(channel); // ok: there is no channel 3859 3860 // Assert full L2CAP header present 3861 if (size < COMPLETE_L2CAP_HEADER) return; 3862 3863 // Dispatch to Classic or LE handler (SCO packets are not dispatched to L2CAP) 3864 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 3865 hci_connection_t *conn = hci_connection_for_handle(handle); 3866 if (!conn) return; 3867 if (conn->address_type == BD_ADDR_TYPE_ACL){ 3868 l2cap_acl_classic_handler(handle, packet, size); 3869 } else { 3870 l2cap_acl_le_handler(handle, packet, size); 3871 } 3872 3873 l2cap_run(); 3874 } 3875 3876 // Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol 3877 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id) { 3878 l2cap_fixed_channel_t * channel = l2cap_fixed_channel_for_channel_id(channel_id); 3879 if (!channel) return; 3880 channel->packet_handler = packet_handler; 3881 } 3882 3883 #ifdef ENABLE_CLASSIC 3884 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 3885 void l2cap_finialize_channel_close(l2cap_channel_t * channel){ 3886 channel->state = L2CAP_STATE_CLOSED; 3887 l2cap_handle_channel_closed(channel); 3888 // discard channel 3889 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 3890 l2cap_free_channel_entry(channel); 3891 } 3892 #endif 3893 3894 #ifdef L2CAP_USES_CHANNELS 3895 static l2cap_service_t * l2cap_get_service_internal(btstack_linked_list_t * services, uint16_t psm){ 3896 btstack_linked_list_iterator_t it; 3897 btstack_linked_list_iterator_init(&it, services); 3898 while (btstack_linked_list_iterator_has_next(&it)){ 3899 l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it); 3900 if ( service->psm == psm){ 3901 return service; 3902 }; 3903 } 3904 return NULL; 3905 } 3906 #endif 3907 3908 #ifdef ENABLE_CLASSIC 3909 static inline l2cap_service_t * l2cap_get_service(uint16_t psm){ 3910 return l2cap_get_service_internal(&l2cap_services, psm); 3911 } 3912 3913 static void l2cap_update_minimal_security_level(void){ 3914 // update minimal service security level 3915 gap_security_level_t minimal_level = LEVEL_1; 3916 btstack_linked_list_iterator_t it; 3917 btstack_linked_list_iterator_init(&it, &l2cap_services); 3918 while (btstack_linked_list_iterator_has_next(&it)){ 3919 l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it); 3920 if (service->required_security_level > minimal_level){ 3921 minimal_level = service->required_security_level; 3922 }; 3923 } 3924 gap_set_minimal_service_security_level(minimal_level); 3925 } 3926 3927 uint8_t l2cap_register_service(btstack_packet_handler_t service_packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level){ 3928 3929 log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u", psm, mtu); 3930 3931 // check for alread registered psm 3932 l2cap_service_t *service = l2cap_get_service(psm); 3933 if (service) { 3934 log_error("register: PSM %u already registered", psm); 3935 return L2CAP_SERVICE_ALREADY_REGISTERED; 3936 } 3937 3938 // alloc structure 3939 service = btstack_memory_l2cap_service_get(); 3940 if (!service) { 3941 log_error("register: no memory for l2cap_service_t"); 3942 return BTSTACK_MEMORY_ALLOC_FAILED; 3943 } 3944 3945 // fill in 3946 service->psm = psm; 3947 service->mtu = mtu; 3948 service->packet_handler = service_packet_handler; 3949 service->required_security_level = security_level; 3950 3951 // add to services list 3952 btstack_linked_list_add(&l2cap_services, (btstack_linked_item_t *) service); 3953 3954 l2cap_update_minimal_security_level(); 3955 3956 #ifndef ENABLE_EXPLICIT_CONNECTABLE_MODE_CONTROL 3957 // enable page scan 3958 gap_connectable_control(1); 3959 #endif 3960 3961 3962 return ERROR_CODE_SUCCESS; 3963 } 3964 3965 uint8_t l2cap_unregister_service(uint16_t psm){ 3966 3967 log_info("unregister psm 0x%x", psm); 3968 3969 l2cap_service_t *service = l2cap_get_service(psm); 3970 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 3971 btstack_linked_list_remove(&l2cap_services, (btstack_linked_item_t *) service); 3972 btstack_memory_l2cap_service_free(service); 3973 3974 l2cap_update_minimal_security_level(); 3975 3976 #ifndef ENABLE_EXPLICIT_CONNECTABLE_MODE_CONTROL 3977 // disable page scan when no services registered 3978 if (btstack_linked_list_empty(&l2cap_services)) { 3979 gap_connectable_control(0); 3980 } 3981 #endif 3982 3983 return ERROR_CODE_SUCCESS; 3984 } 3985 #endif 3986 3987 3988 #ifdef ENABLE_LE_DATA_CHANNELS 3989 3990 static void l2cap_le_notify_channel_can_send(l2cap_channel_t *channel){ 3991 if (!channel->waiting_for_can_send_now) return; 3992 if (channel->send_sdu_buffer) return; 3993 channel->waiting_for_can_send_now = 0; 3994 log_debug("le can send now, local_cid 0x%x", channel->local_cid); 3995 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_CAN_SEND_NOW); 3996 } 3997 3998 // 1BH2222 3999 static void l2cap_emit_le_incoming_connection(l2cap_channel_t *channel) { 4000 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", 4001 channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, channel->local_cid, channel->remote_cid, channel->remote_mtu); 4002 uint8_t event[19]; 4003 event[0] = L2CAP_EVENT_LE_INCOMING_CONNECTION; 4004 event[1] = sizeof(event) - 2u; 4005 event[2] = channel->address_type; 4006 reverse_bd_addr(channel->address, &event[3]); 4007 little_endian_store_16(event, 9, channel->con_handle); 4008 little_endian_store_16(event, 11, channel->psm); 4009 little_endian_store_16(event, 13, channel->local_cid); 4010 little_endian_store_16(event, 15, channel->remote_cid); 4011 little_endian_store_16(event, 17, channel->remote_mtu); 4012 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4013 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4014 } 4015 // 11BH22222 4016 static void l2cap_emit_le_channel_opened(l2cap_channel_t *channel, uint8_t status) { 4017 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", 4018 status, channel->address_type, bd_addr_to_str(channel->address), channel->con_handle, channel->psm, 4019 channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu); 4020 uint8_t event[23]; 4021 event[0] = L2CAP_EVENT_LE_CHANNEL_OPENED; 4022 event[1] = sizeof(event) - 2u; 4023 event[2] = status; 4024 event[3] = channel->address_type; 4025 reverse_bd_addr(channel->address, &event[4]); 4026 little_endian_store_16(event, 10, channel->con_handle); 4027 event[12] = (channel->state_var & L2CAP_CHANNEL_STATE_VAR_INCOMING) ? 1 : 0; 4028 little_endian_store_16(event, 13, channel->psm); 4029 little_endian_store_16(event, 15, channel->local_cid); 4030 little_endian_store_16(event, 17, channel->remote_cid); 4031 little_endian_store_16(event, 19, channel->local_mtu); 4032 little_endian_store_16(event, 21, channel->remote_mtu); 4033 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4034 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4035 } 4036 // 2 4037 static void l2cap_emit_le_channel_closed(l2cap_channel_t * channel){ 4038 log_info("closed local_cid 0x%x", channel->local_cid); 4039 uint8_t event[4]; 4040 event[0] = L2CAP_EVENT_LE_CHANNEL_CLOSED; 4041 event[1] = sizeof(event) - 2u; 4042 little_endian_store_16(event, 2, channel->local_cid); 4043 hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event)); 4044 l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event)); 4045 } 4046 4047 static void l2cap_le_send_pdu(l2cap_channel_t *channel){ 4048 btstack_assert(channel != NULL); 4049 btstack_assert(channel->send_sdu_buffer != NULL); 4050 btstack_assert(channel->credits_outgoing > 0); 4051 4052 // send part of SDU 4053 hci_reserve_packet_buffer(); 4054 uint8_t * acl_buffer = hci_get_outgoing_packet_buffer(); 4055 uint8_t * l2cap_payload = acl_buffer + 8; 4056 uint16_t pos = 0; 4057 if (!channel->send_sdu_pos){ 4058 // store SDU len 4059 channel->send_sdu_pos += 2u; 4060 little_endian_store_16(l2cap_payload, pos, channel->send_sdu_len); 4061 pos += 2u; 4062 } 4063 uint16_t payload_size = btstack_min(channel->send_sdu_len + 2u - channel->send_sdu_pos, channel->remote_mps - pos); 4064 log_info("len %u, pos %u => payload %u, credits %u", channel->send_sdu_len, channel->send_sdu_pos, payload_size, channel->credits_outgoing); 4065 (void)memcpy(&l2cap_payload[pos], 4066 &channel->send_sdu_buffer[channel->send_sdu_pos - 2u], 4067 payload_size); // -2 for virtual SDU len 4068 pos += payload_size; 4069 channel->send_sdu_pos += payload_size; 4070 l2cap_setup_header(acl_buffer, channel->con_handle, 0, channel->remote_cid, pos); 4071 4072 channel->credits_outgoing--; 4073 4074 hci_send_acl_packet_buffer(8u + pos); 4075 4076 if (channel->send_sdu_pos >= (channel->send_sdu_len + 2u)){ 4077 channel->send_sdu_buffer = NULL; 4078 // send done event 4079 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_LE_PACKET_SENT); 4080 // inform about can send now 4081 l2cap_le_notify_channel_can_send(channel); 4082 } 4083 } 4084 4085 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE 4086 void l2cap_le_finialize_channel_close(l2cap_channel_t * channel){ 4087 channel->state = L2CAP_STATE_CLOSED; 4088 l2cap_emit_simple_event_with_cid(channel, L2CAP_EVENT_CHANNEL_CLOSED); 4089 // discard channel 4090 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 4091 l2cap_free_channel_entry(channel); 4092 } 4093 4094 static inline l2cap_service_t * l2cap_le_get_service(uint16_t le_psm){ 4095 return l2cap_get_service_internal(&l2cap_le_services, le_psm); 4096 } 4097 4098 uint8_t l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level){ 4099 4100 log_info("L2CAP_LE_REGISTER_SERVICE psm 0x%x", psm); 4101 4102 // check for alread registered psm 4103 l2cap_service_t *service = l2cap_le_get_service(psm); 4104 if (service) { 4105 return L2CAP_SERVICE_ALREADY_REGISTERED; 4106 } 4107 4108 // alloc structure 4109 service = btstack_memory_l2cap_service_get(); 4110 if (!service) { 4111 log_error("register: no memory for l2cap_service_t"); 4112 return BTSTACK_MEMORY_ALLOC_FAILED; 4113 } 4114 4115 // fill in 4116 service->psm = psm; 4117 service->mtu = 0; 4118 service->packet_handler = packet_handler; 4119 service->required_security_level = security_level; 4120 4121 // add to services list 4122 btstack_linked_list_add(&l2cap_le_services, (btstack_linked_item_t *) service); 4123 4124 // done 4125 return ERROR_CODE_SUCCESS; 4126 } 4127 4128 uint8_t l2cap_le_unregister_service(uint16_t psm) { 4129 log_info("L2CAP_LE_UNREGISTER_SERVICE psm 0x%x", psm); 4130 l2cap_service_t *service = l2cap_le_get_service(psm); 4131 if (!service) return L2CAP_SERVICE_DOES_NOT_EXIST; 4132 4133 btstack_linked_list_remove(&l2cap_le_services, (btstack_linked_item_t *) service); 4134 btstack_memory_l2cap_service_free(service); 4135 return ERROR_CODE_SUCCESS; 4136 } 4137 4138 uint8_t l2cap_le_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits){ 4139 // get channel 4140 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4141 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4142 4143 // validate state 4144 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 4145 return ERROR_CODE_COMMAND_DISALLOWED; 4146 } 4147 4148 // set state accept connection 4149 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT; 4150 channel->receive_sdu_buffer = receive_sdu_buffer; 4151 channel->local_mtu = mtu; 4152 channel->new_credits_incoming = initial_credits; 4153 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 4154 4155 // test 4156 // channel->new_credits_incoming = 1; 4157 4158 // go 4159 l2cap_run(); 4160 return ERROR_CODE_SUCCESS; 4161 } 4162 4163 /** 4164 * @brief Deny incoming LE Data Channel connection due to resource constraints 4165 * @param local_cid L2CAP LE Data Channel Identifier 4166 */ 4167 4168 uint8_t l2cap_le_decline_connection(uint16_t local_cid){ 4169 // get channel 4170 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4171 if (!channel) return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4172 4173 // validate state 4174 if (channel->state != L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT){ 4175 return ERROR_CODE_COMMAND_DISALLOWED; 4176 } 4177 4178 // set state decline connection 4179 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE; 4180 channel->reason = 0x04; // no resources available 4181 l2cap_run(); 4182 return ERROR_CODE_SUCCESS; 4183 } 4184 4185 static gap_security_level_t l2cap_le_security_level_for_connection(hci_con_handle_t con_handle){ 4186 uint8_t encryption_key_size = gap_encryption_key_size(con_handle); 4187 if (encryption_key_size == 0) return LEVEL_0; 4188 4189 uint8_t authenticated = gap_authenticated(con_handle); 4190 if (!authenticated) return LEVEL_2; 4191 4192 return encryption_key_size == 16 ? LEVEL_4 : LEVEL_3; 4193 } 4194 4195 // used to handle pairing complete after triggering to increase 4196 static void l2cap_sm_packet_handler(uint8_t packet_type, uint16_t channel_nr, uint8_t *packet, uint16_t size) { 4197 UNUSED(channel_nr); 4198 UNUSED(size); 4199 UNUSED(packet_type); 4200 btstack_assert(packet_type == HCI_EVENT_PACKET); 4201 if (hci_event_packet_get_type(packet) != SM_EVENT_PAIRING_COMPLETE) return; 4202 hci_con_handle_t con_handle = sm_event_pairing_complete_get_handle(packet); 4203 btstack_linked_list_iterator_t it; 4204 btstack_linked_list_iterator_init(&it, &l2cap_channels); 4205 while (btstack_linked_list_iterator_has_next(&it)) { 4206 l2cap_channel_t *channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it); 4207 if (!l2cap_is_dynamic_channel_type(channel->channel_type)) continue; 4208 if (channel->con_handle != con_handle) continue; 4209 if (channel->state != L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE) continue; 4210 4211 // found channel, check security level 4212 if (l2cap_le_security_level_for_connection(con_handle) < channel->required_security_level){ 4213 // pairing failed or wasn't good enough, inform user 4214 l2cap_emit_le_channel_opened(channel, ERROR_CODE_INSUFFICIENT_SECURITY); 4215 // discard channel 4216 btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel); 4217 l2cap_free_channel_entry(channel); 4218 } else { 4219 // send conn request now 4220 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST; 4221 l2cap_run(); 4222 } 4223 } 4224 } 4225 4226 uint8_t l2cap_le_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, 4227 uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level, 4228 uint16_t * out_local_cid) { 4229 4230 static btstack_packet_callback_registration_t sm_event_callback_registration; 4231 static bool sm_callback_registered = false; 4232 4233 log_info("create, handle 0x%04x psm 0x%x mtu %u", con_handle, psm, mtu); 4234 4235 hci_connection_t * connection = hci_connection_for_handle(con_handle); 4236 if (!connection) { 4237 log_error("no hci_connection for handle 0x%04x", con_handle); 4238 return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 4239 } 4240 4241 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); 4242 if (!channel) { 4243 return BTSTACK_MEMORY_ALLOC_FAILED; 4244 } 4245 log_info("created %p", channel); 4246 4247 // store local_cid 4248 if (out_local_cid){ 4249 *out_local_cid = channel->local_cid; 4250 } 4251 4252 // setup channel entry 4253 channel->con_handle = con_handle; 4254 channel->receive_sdu_buffer = receive_sdu_buffer; 4255 channel->new_credits_incoming = initial_credits; 4256 channel->automatic_credits = initial_credits == L2CAP_LE_AUTOMATIC_CREDITS; 4257 4258 // add to connections list 4259 btstack_linked_list_add_tail(&l2cap_channels, (btstack_linked_item_t *) channel); 4260 4261 // check security level 4262 if (l2cap_le_security_level_for_connection(con_handle) < channel->required_security_level){ 4263 if (!sm_callback_registered){ 4264 sm_callback_registered = true; 4265 // lazy registration for SM events 4266 sm_event_callback_registration.callback = &l2cap_sm_packet_handler; 4267 sm_add_event_handler(&sm_event_callback_registration); 4268 } 4269 4270 // start pairing 4271 channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE; 4272 sm_request_pairing(con_handle); 4273 } else { 4274 // send conn request right away 4275 channel->state = L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST; 4276 l2cap_run(); 4277 } 4278 4279 return ERROR_CODE_SUCCESS; 4280 } 4281 4282 /** 4283 * @brief Provide credtis for LE Data Channel 4284 * @param local_cid L2CAP LE Data Channel Identifier 4285 * @param credits Number additional credits for peer 4286 */ 4287 uint8_t l2cap_le_provide_credits(uint16_t local_cid, uint16_t credits){ 4288 4289 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4290 if (!channel) { 4291 log_error("le credits no channel for cid 0x%02x", local_cid); 4292 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4293 } 4294 4295 // check state 4296 if (channel->state != L2CAP_STATE_OPEN){ 4297 log_error("le credits but channel 0x%02x not open yet", local_cid); 4298 } 4299 4300 // assert incoming credits + credits <= 0xffff 4301 uint32_t total_credits = channel->credits_incoming; 4302 total_credits += channel->new_credits_incoming; 4303 total_credits += credits; 4304 if (total_credits > 0xffffu){ 4305 log_error("le credits overrun: current %u, scheduled %u, additional %u", channel->credits_incoming, 4306 channel->new_credits_incoming, credits); 4307 } 4308 4309 // set credits_granted 4310 channel->new_credits_incoming += credits; 4311 4312 // go 4313 l2cap_run(); 4314 return ERROR_CODE_SUCCESS; 4315 } 4316 4317 /** 4318 * @brief Check if outgoing buffer is available and that there's space on the Bluetooth module 4319 * @param local_cid L2CAP LE Data Channel Identifier 4320 */ 4321 bool l2cap_le_can_send_now(uint16_t local_cid){ 4322 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4323 if (!channel) { 4324 log_error("le can send now, no channel for cid 0x%02x", local_cid); 4325 return false; 4326 } 4327 4328 // check state 4329 if (channel->state != L2CAP_STATE_OPEN) return false; 4330 4331 // check queue 4332 if (channel->send_sdu_buffer) return false; 4333 4334 // fine, go ahead 4335 return true; 4336 } 4337 4338 /** 4339 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible 4340 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 4341 * so packet handler should be ready to handle it 4342 * @param local_cid L2CAP LE Data Channel Identifier 4343 */ 4344 uint8_t l2cap_le_request_can_send_now_event(uint16_t local_cid){ 4345 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4346 if (!channel) { 4347 log_error("can send now, no channel for cid 0x%02x", local_cid); 4348 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4349 } 4350 channel->waiting_for_can_send_now = 1; 4351 l2cap_le_notify_channel_can_send(channel); 4352 return ERROR_CODE_SUCCESS; 4353 } 4354 4355 /** 4356 * @brief Send data via LE Data Channel 4357 * @note Since data larger then the maximum PDU needs to be segmented into multiple PDUs, data needs to stay valid until ... event 4358 * @param local_cid L2CAP LE Data Channel Identifier 4359 * @param data data to send 4360 * @param size data size 4361 */ 4362 uint8_t l2cap_le_send_data(uint16_t local_cid, uint8_t * data, uint16_t size){ 4363 4364 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4365 if (!channel) { 4366 log_error("l2cap send, no channel for cid 0x%02x", local_cid); 4367 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4368 } 4369 4370 if (size > channel->remote_mtu){ 4371 log_error("l2cap send, cid 0x%02x, data length exceeds remote MTU.", local_cid); 4372 return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU; 4373 } 4374 4375 if (channel->send_sdu_buffer){ 4376 log_info("l2cap send, cid 0x%02x, cannot send", local_cid); 4377 return BTSTACK_ACL_BUFFERS_FULL; 4378 } 4379 4380 channel->send_sdu_buffer = data; 4381 channel->send_sdu_len = size; 4382 channel->send_sdu_pos = 0; 4383 4384 l2cap_notify_channel_can_send(); 4385 return ERROR_CODE_SUCCESS; 4386 } 4387 4388 /** 4389 * @brief Disconnect from LE Data Channel 4390 * @param local_cid L2CAP LE Data Channel Identifier 4391 */ 4392 uint8_t l2cap_le_disconnect(uint16_t local_cid) 4393 { 4394 l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid); 4395 if (!channel) { 4396 log_error("l2cap send, no channel for cid 0x%02x", local_cid); 4397 return L2CAP_LOCAL_CID_DOES_NOT_EXIST; 4398 } 4399 4400 channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST; 4401 l2cap_run(); 4402 return ERROR_CODE_SUCCESS; 4403 } 4404 4405 #endif 4406