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