xref: /btstack/src/l2cap.h (revision e8b7768f4320b89e088aeff6b8ffd5c9b51f3338)
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  *
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9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
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15  *    from this software without specific prior written permission.
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19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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36  */
37 
38 /**
39  * @title L2CAP
40  *
41  * Logical Link Control and Adaption Protocol
42  *
43  */
44 
45 #ifndef L2CAP_H
46 #define L2CAP_H
47 
48 #include "hci.h"
49 #include "l2cap_signaling.h"
50 #include "btstack_util.h"
51 #include "bluetooth.h"
52 
53 #if defined __cplusplus
54 extern "C" {
55 #endif
56 
57 // check L2CAP MTU
58 #ifdef ENABLE_CLASSIC
59 #if (L2CAP_HEADER_SIZE + L2CAP_MINIMAL_MTU) > HCI_ACL_PAYLOAD_SIZE
60 #error "HCI_ACL_PAYLOAD_SIZE too small for minimal L2CAP MTU of 48 bytes"
61 #endif
62 #endif
63 #ifdef ENABLE_BLE
64 #if (L2CAP_HEADER_SIZE + L2CAP_LE_DEFAULT_MTU) > HCI_ACL_PAYLOAD_SIZE
65 #error "HCI_ACL_PAYLOAD_SIZE too small for minimal L2CAP LE MTU of 23 bytes"
66 #endif
67 #endif
68 
69 #define L2CAP_LE_AUTOMATIC_CREDITS 0xffff
70 
71 // private structs
72 typedef enum {
73     L2CAP_STATE_CLOSED = 1,           // no baseband
74     L2CAP_STATE_WILL_SEND_CREATE_CONNECTION,
75     L2CAP_STATE_WAIT_CONNECTION_COMPLETE,
76     L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES,
77     L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE,
78     L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE,
79     L2CAP_STATE_WAIT_INCOMING_EXTENDED_FEATURES,    // only for Enhanced Retransmission Mode
80     L2CAP_STATE_WAIT_OUTGOING_EXTENDED_FEATURES,    // only for Enhanced Retransmission Mode
81     L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT,
82     L2CAP_STATE_WAIT_CONNECT_RSP, // from peer
83     L2CAP_STATE_CONFIG,
84     L2CAP_STATE_OPEN,
85     L2CAP_STATE_WAIT_DISCONNECT,  // from application
86     L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST,
87     L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_INSUFFICIENT_SECURITY,
88     L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE,
89     L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT,
90     L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST,
91     L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE,
92     L2CAP_STATE_WILL_SEND_LE_CONNECTION_REQUEST,
93     L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_DECLINE,
94     L2CAP_STATE_WILL_SEND_LE_CONNECTION_RESPONSE_ACCEPT,
95     L2CAP_STATE_WAIT_LE_CONNECTION_RESPONSE,
96     L2CAP_STATE_EMIT_OPEN_FAILED_AND_DISCARD,
97     L2CAP_STATE_WILL_SEND_ENHANCED_CONNECTION_REQUEST,
98     L2CAP_STATE_WAIT_ENHANCED_CONNECTION_RESPONSE,
99     L2CAP_STATE_WILL_SEND_ENHANCED_CONNECTION_RESPONSE,
100     L2CAP_STATE_WILL_SEND_EHNANCED_RENEGOTIATION_REQUEST,
101     L2CAP_STATE_WAIT_ENHANCED_RENEGOTIATION_RESPONSE,
102     L2CAP_STATE_INVALID,
103 } L2CAP_STATE;
104 
105 #define L2CAP_CHANNEL_STATE_VAR_NONE                   0
106 #define L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ          1 << 0
107 #define L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP          1 << 1
108 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ          1 << 2
109 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP          1 << 3
110 #define L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ          1 << 4
111 #define L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP          1 << 5
112 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU      1 << 6   // in CONF RSP, add MTU option
113 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_ERTM     1 << 7   // in CONF RSP, add Retransmission and Flowcontrol option
114 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT     1 << 8   // in CONF RSP, set CONTINUE flag
115 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID  1 << 9   // in CONF RSP, send UNKNOWN OPTIONS
116 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_REJECTED 1 << 10  // in CONF RSP, send Unacceptable Parameters (ERTM)
117 #define L2CAP_CHANNEL_STATE_VAR_BASIC_FALLBACK_TRIED   1 << 11  // set when ERTM was requested but we want only Basic mode (ERM)
118 #define L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND    1 << 12  // send Connection Respond with pending
119 #define L2CAP_CHANNEL_STATE_VAR_SENT_CONN_RESP_PEND    1 << 13  // send CMD_REJ with reason unknown
120 #define L2CAP_CHANNEL_STATE_VAR_INCOMING               1 << 15  // channel is incoming
121 
122 
123 typedef enum {
124     L2CAP_CHANNEL_TYPE_CLASSIC,         // Classic Basic or ERTM
125     L2CAP_CHANNEL_TYPE_CONNECTIONLESS,  // Classic Connectionless
126     L2CAP_CHANNEL_TYPE_CHANNEL_CBM,     // LE
127     L2CAP_CHANNEL_TYPE_FIXED_LE,        // LE ATT + SM
128     L2CAP_CHANNEL_TYPE_FIXED_CLASSIC,   // Classic SM
129     L2CAP_CHANNEL_TYPE_CHANNEL_ECBM     // Classic + LE
130 } l2cap_channel_type_t;
131 
132 
133 /*
134  * @brief L2CAP Segmentation And Reassembly packet type in I-Frames
135  */
136 typedef enum {
137     L2CAP_SEGMENTATION_AND_REASSEMBLY_UNSEGMENTED_L2CAP_SDU = 0,
138     L2CAP_SEGMENTATION_AND_REASSEMBLY_START_OF_L2CAP_SDU,
139     L2CAP_SEGMENTATION_AND_REASSEMBLY_END_OF_L2CAP_SDU,
140     L2CAP_SEGMENTATION_AND_REASSEMBLY_CONTINUATION_OF_L2CAP_SDU
141 } l2cap_segmentation_and_reassembly_t;
142 
143 typedef struct {
144     l2cap_segmentation_and_reassembly_t sar;
145     uint16_t len;
146     uint8_t  valid;
147 } l2cap_ertm_rx_packet_state_t;
148 
149 typedef struct {
150     l2cap_segmentation_and_reassembly_t sar;
151     uint16_t len;
152     uint8_t tx_seq;
153     uint8_t retry_count;
154     uint8_t retransmission_requested;
155 } l2cap_ertm_tx_packet_state_t;
156 
157 typedef struct {
158     // If not mandatory, the use of ERTM can be decided by the remote
159     uint8_t  ertm_mandatory;
160 
161     // Number of retransmissions that L2CAP is allowed to try before accepting that a packet and the channel is lost.
162     uint8_t  max_transmit;
163 
164     // time before retransmission of i-frame / Recommended : 2000 ms (ACL Flush timeout not used)
165     uint16_t retransmission_timeout_ms;
166 
167     // time after withc s-frames are sent / Recommended: 12000 ms (ACL Flush timeout not used)
168     uint16_t monitor_timeout_ms;
169 
170     // MTU for incoming SDUs
171     uint16_t local_mtu;
172 
173     // Number of buffers for outgoing data
174     uint8_t num_tx_buffers;
175 
176     // Number of packets that can be received out of order (-> our tx_window size)
177     uint8_t num_rx_buffers;
178 
179     // Frame Check Sequence (FCS) Option
180     uint8_t fcs_option;
181 
182 } l2cap_ertm_config_t;
183 
184 // info regarding an actual channel
185 // note: l2cap_fixed_channel and l2cap_channel_t share commmon fields
186 
187 typedef struct l2cap_fixed_channel {
188     // linked list - assert: first field
189     btstack_linked_item_t    item;
190 
191     // channel type
192     l2cap_channel_type_t channel_type;
193 
194     // local cid, primary key for channel lookup
195     uint16_t  local_cid;
196 
197     // packet handler
198     btstack_packet_handler_t packet_handler;
199 
200     // send request
201     uint8_t waiting_for_can_send_now;
202 
203     // -- end of shared prefix
204 
205 } l2cap_fixed_channel_t;
206 
207 typedef struct {
208     // linked list - assert: first field
209     btstack_linked_item_t    item;
210 
211     // channel type
212     l2cap_channel_type_t channel_type;
213 
214     // local cid, primary key for channel lookup
215     uint16_t  local_cid;
216 
217     // packet handler
218     btstack_packet_handler_t packet_handler;
219 
220     // send request
221     uint8_t   waiting_for_can_send_now;
222 
223     // -- end of shared prefix
224 
225     // timer
226     btstack_timer_source_t rtx; // also used for ertx
227 
228     L2CAP_STATE state;
229     uint16_t    state_var;
230 
231     // info
232     hci_con_handle_t con_handle;
233 
234     bd_addr_t address;
235     bd_addr_type_t address_type;
236 
237     uint8_t   remote_sig_id;    // used by other side, needed for delayed response
238     uint8_t   local_sig_id;     // own signaling identifier
239 
240     uint16_t  remote_cid;
241 
242     uint16_t  local_mtu;
243     uint16_t  remote_mtu;
244 
245     uint16_t  flush_timeout;    // default 0xffff
246 
247     uint16_t  psm;
248 
249     gap_security_level_t required_security_level;
250 
251     uint16_t   reason; // used in decline internal
252 
253     uint8_t   unknown_option; // used for ConfigResponse
254 
255     // Credit-Based Flow-Control mode
256 
257     // incoming SDU
258     uint8_t * receive_sdu_buffer;
259     uint16_t  receive_sdu_len;
260     uint16_t  receive_sdu_pos;
261 
262 #ifdef ENABLE_L2CAP_ENHANCED_CREDIT_BASED_FLOW_CONTROL_MODE
263     uint8_t * renegotiate_sdu_buffer;
264     uint16_t  renegotiate_mtu;
265 #endif
266 
267     // outgoing SDU
268     const uint8_t * send_sdu_buffer;
269     uint16_t   send_sdu_len;
270     uint16_t   send_sdu_pos;
271 
272     // max PDU size
273     uint16_t  local_mps;
274     uint16_t  remote_mps;
275 
276     // credits for outgoing traffic
277     uint16_t credits_outgoing;
278 
279     // number of packets remote will be granted
280     uint16_t new_credits_incoming;
281 
282     // credits for incoming traffic
283     uint16_t credits_incoming;
284 
285     // automatic credits incoming
286     bool automatic_credits;
287 
288 #ifdef ENABLE_L2CAP_ENHANCED_CREDIT_BASED_FLOW_CONTROL_MODE
289     uint8_t cid_index;
290     uint8_t num_cids;
291 #endif
292 
293 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE
294 
295     // l2cap channel mode: basic or enhanced retransmission mode
296     l2cap_channel_mode_t mode;
297 
298     // retransmission timer
299     btstack_timer_source_t retransmission_timer;
300 
301     // monitor timer
302     btstack_timer_source_t monitor_timer;
303 
304     // local/remote config options
305     uint16_t local_retransmission_timeout_ms;
306     uint16_t local_monitor_timeout_ms;
307 
308     uint16_t remote_retransmission_timeout_ms;
309     uint16_t remote_monitor_timeout_ms;
310 
311     uint8_t remote_tx_window_size;
312 
313     uint8_t local_max_transmit;
314     uint8_t remote_max_transmit;
315 
316     // if ertm is not mandatory, allow fallback to L2CAP Basic Mode - flag
317     uint8_t ertm_mandatory;
318 
319     // Frame Chech Sequence (crc16) is present in both directions
320     uint8_t fcs_option;
321 
322     // sender: max num of stored outgoing frames
323     uint8_t num_tx_buffers;
324 
325     // sender: num stored outgoing frames
326     uint8_t num_stored_tx_frames;
327 
328     // sender: number of unacknowledeged I-Frames - frames have been sent, but not acknowledged yet
329     uint8_t unacked_frames;
330 
331     // sender: buffer index of oldest packet
332     uint8_t tx_read_index;
333 
334     // sender: buffer index to store next tx packet
335     uint8_t tx_write_index;
336 
337     // sender: buffer index of packet to send next
338     uint8_t tx_send_index;
339 
340     // sender: next seq nr used for sending
341     uint8_t next_tx_seq;
342 
343     // sender: selective retransmission requested
344     uint8_t srej_active;
345 
346 
347     // receiver: max num out-of-order packets // tx_window
348     uint8_t num_rx_buffers;
349 
350     // receiver: buffer index of to store packet with delta = 1
351     uint8_t rx_store_index;
352 
353     // receiver: value of tx_seq in next expected i-frame
354     uint8_t expected_tx_seq;
355 
356     // receiver: request transmission with tx_seq = req_seq and ack up to and including req_seq
357     uint8_t req_seq;
358 
359     // receiver: local busy condition
360     uint8_t local_busy;
361 
362     // receiver: send RR frame with optional final flag set - flag
363     uint8_t send_supervisor_frame_receiver_ready;
364 
365     // receiver: send RR frame with poll bit set
366     uint8_t send_supervisor_frame_receiver_ready_poll;
367 
368     // receiver: send RNR frame - flag
369     uint8_t send_supervisor_frame_receiver_not_ready;
370 
371     // receiver: send REJ frame - flag
372     uint8_t send_supervisor_frame_reject;
373 
374     // receiver: send SREJ frame - flag
375     uint8_t send_supervisor_frame_selective_reject;
376 
377     // set final bit after poll packet with poll bit was received
378     uint8_t set_final_bit_after_packet_with_poll_bit_set;
379 
380     // receiver: meta data for out-of-order frames
381     l2cap_ertm_rx_packet_state_t * rx_packets_state;
382 
383     // sender: retransmission state
384     l2cap_ertm_tx_packet_state_t * tx_packets_state;
385 
386     // receiver: reassemly pos
387     uint16_t reassembly_pos;
388 
389     // receiver: reassemly sdu length
390     uint16_t reassembly_sdu_length;
391 
392     // receiver: eassembly buffer
393     uint8_t * reassembly_buffer;
394 
395     // receiver: num_rx_buffers of size local_mps
396     uint8_t * rx_packets_data;
397 
398     // sender: num_tx_buffers of size local_mps
399     uint8_t * tx_packets_data;
400 
401 #endif
402 } l2cap_channel_t;
403 
404 // info regarding potential connections
405 typedef struct {
406     // linked list - assert: first field
407     btstack_linked_item_t    item;
408 
409     // service id
410     uint16_t  psm;
411 
412     // max local mtu for basic mode, min remote mtu for enhanced credit-based flow-control mode
413     uint16_t mtu;
414 
415     // internal connection
416     btstack_packet_handler_t packet_handler;
417 
418     // required security level
419     gap_security_level_t required_security_level;
420 
421     // requires authorization
422     bool requires_authorization;
423 
424 } l2cap_service_t;
425 
426 
427 typedef struct l2cap_signaling_response {
428     hci_con_handle_t handle;
429     uint8_t  sig_id;
430     uint8_t  code;
431     uint16_t cid;  // source cid for CONNECTION REQUEST
432     uint16_t data; // infoType for INFORMATION REQUEST, result for CONNECTION REQUEST and COMMAND UNKNOWN
433 } l2cap_signaling_response_t;
434 
435 
436 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id);
437 bool l2cap_can_send_fixed_channel_packet_now(hci_con_handle_t con_handle, uint16_t channel_id);
438 void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t channel_id);
439 uint8_t l2cap_send_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint8_t *data, uint16_t len);
440 uint8_t l2cap_send_prepared_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint16_t len);
441 
442 // PTS Testing
443 int l2cap_send_echo_request(hci_con_handle_t con_handle, uint8_t *data, uint16_t len);
444 void l2cap_require_security_level_2_for_outgoing_sdp(void);
445 
446 // Used by RFCOMM - similar to l2cap_can-send_packet_now but does not check if outgoing buffer is reserved
447 bool l2cap_can_send_prepared_packet_now(uint16_t local_cid);
448 
449 /* API_START */
450 
451 //
452 // PSM numbers from https://www.bluetooth.com/specifications/assigned-numbers/logical-link-control
453 //
454 #define PSM_SDP           BLUETOOTH_PROTOCOL_SDP
455 #define PSM_RFCOMM        BLUETOOTH_PROTOCOL_RFCOMM
456 #define PSM_BNEP          BLUETOOTH_PROTOCOL_BNEP
457 // @TODO: scrape PSMs Bluetooth SIG site and put in bluetooth_psm.h or bluetooth_l2cap.h
458 #define PSM_HID_CONTROL   0x11
459 #define PSM_HID_INTERRUPT 0x13
460 #define PSM_ATT           0x1f
461 #define PSM_IPSP          0x23
462 
463 /**
464  * @brief Set up L2CAP and register L2CAP with HCI layer.
465  */
466 void l2cap_init(void);
467 
468 /**
469  * @brief Add event packet handler for LE Connection Parameter Update events
470  */
471 void l2cap_add_event_handler(btstack_packet_callback_registration_t * callback_handler);
472 
473 /**
474  * @brief Remove event packet handler.
475  */
476 void l2cap_remove_event_handler(btstack_packet_callback_registration_t * callback_handler);
477 
478 /**
479  * @brief Get max MTU for Classic connections based on btstack configuration
480  */
481 uint16_t l2cap_max_mtu(void);
482 
483 /**
484  * @brief Get max MTU for LE connections based on btstack configuration
485  */
486 uint16_t l2cap_max_le_mtu(void);
487 
488 /**
489 * @brief Set the max MTU for LE connections, if not set l2cap_max_mtu() will be used.
490 */
491 void l2cap_set_max_le_mtu(uint16_t max_mtu);
492 
493 /**
494  * @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary.
495  * @param packet_handler
496  * @param address
497  * @param psm
498  * @param mtu
499  * @param local_cid
500  * @return status
501  */
502 uint8_t l2cap_create_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm, uint16_t mtu, uint16_t * out_local_cid);
503 
504 /**
505  * @brief Disconnects L2CAP channel with given identifier.
506  * @param local_cid
507  * @return status ERROR_CODE_SUCCESS if successful or L2CAP_LOCAL_CID_DOES_NOT_EXIST
508  */
509 uint8_t l2cap_disconnect(uint16_t local_cid);
510 
511 /**
512  * @brief Queries the maximal transfer unit (MTU) for L2CAP channel with given identifier.
513  */
514 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid);
515 
516 /**
517  * @brief Sends L2CAP data packet to the channel with given identifier.
518  * @note For channel in credit-based flow control mode, data needs to stay valid until .. event
519  * @param local_cid
520  * @param data to send
521  * @param len of data
522  * @return status
523  */
524 uint8_t l2cap_send(uint16_t local_cid, const uint8_t *data, uint16_t len);
525 
526 /**
527  * @brief Registers L2CAP service with given PSM and MTU, and assigns a packet handler.
528  * @param packet_handler
529  * @param psm
530  * @param mtu
531  * @param security_level
532  * @return status ERROR_CODE_SUCCESS if successful, otherwise L2CAP_SERVICE_ALREADY_REGISTERED or BTSTACK_MEMORY_ALLOC_FAILED
533  */
534 uint8_t l2cap_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level);
535 
536 /**
537  * @brief Unregisters L2CAP service with given PSM.
538  */
539 uint8_t l2cap_unregister_service(uint16_t psm);
540 
541 /**
542  * @brief Accepts incoming L2CAP connection.
543  */
544 void l2cap_accept_connection(uint16_t local_cid);
545 
546 /**
547  * @brief Deny incoming L2CAP connection.
548  */
549 void l2cap_decline_connection(uint16_t local_cid);
550 
551 /**
552  * @brief Check if outgoing buffer is available and that there's space on the Bluetooth module
553  * @return true if packet can be sent
554  */
555 bool l2cap_can_send_packet_now(uint16_t local_cid);
556 
557 /**
558  * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible
559  * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function
560  *       so packet handler should be ready to handle it
561  * @param local_cid
562  * @return status
563  */
564 uint8_t l2cap_request_can_send_now_event(uint16_t local_cid);
565 
566 /**
567  * @brief Reserve outgoing buffer
568  * @note Only for L2CAP Basic Mode Channels
569  * @return true on success
570  */
571 bool l2cap_reserve_packet_buffer(void);
572 
573 /**
574  * @brief Get outgoing buffer and prepare data.
575  * @note Only for L2CAP Basic Mode Channels
576  */
577 uint8_t *l2cap_get_outgoing_buffer(void);
578 
579 /**
580  * @brief Send L2CAP packet prepared in outgoing buffer to channel
581  * @note Only for L2CAP Basic Mode Channels
582  */
583 uint8_t l2cap_send_prepared(uint16_t local_cid, uint16_t len);
584 
585 /**
586  * @brief Release outgoing buffer (only needed if l2cap_send_prepared is not called)
587  * @note Only for L2CAP Basic Mode Channels
588  */
589 void l2cap_release_packet_buffer(void);
590 
591 //
592 // Connection-Oriented Channels in Enhanced Retransmission Mode - ERTM
593 //
594 
595 /**
596  * @brief Creates L2CAP channel to the PSM of a remote device with baseband address using Enhanced Retransmission Mode.
597  *        A new baseband connection will be initiated if necessary.
598  * @param packet_handler
599  * @param address
600  * @param psm
601  * @param ertm_config
602  * @param buffer to store reassembled rx packet, out-of-order packets and unacknowledged outgoing packets with their tretransmission timers
603  * @param size of buffer
604  * @param local_cid
605  * @return status
606  */
607 uint8_t l2cap_ertm_create_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm,
608                                   l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size, uint16_t * out_local_cid);
609 
610 /**
611  * @brief Accepts incoming L2CAP connection for Enhanced Retransmission Mode
612  * @param local_cid
613  * @param ertm_config
614  * @param buffer to store reassembled rx packet, out-of-order packets and unacknowledged outgoing packets with their tretransmission timers
615  * @param size of buffer
616  * @return status
617  */
618 uint8_t l2cap_ertm_accept_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size);
619 
620 /**
621  * @brief Deny incoming incoming L2CAP connection for Enhanced Retransmission Mode
622  * @param local_cid
623  * @return status
624  */
625 uint8_t l2cap_ertm_decline_connection(uint16_t local_cid);
626 
627 /**
628  * @brief ERTM Set channel as busy.
629  * @note Can be cleared by l2cap_ertm_set_ready
630  * @param local_cid
631  * @return status
632  */
633 uint8_t l2cap_ertm_set_busy(uint16_t local_cid);
634 
635 /**
636  * @brief ERTM Set channel as ready
637  * @note Used after l2cap_ertm_set_busy
638  * @param local_cid
639  * @return status
640  */
641 uint8_t l2cap_ertm_set_ready(uint16_t local_cid);
642 
643 
644 //
645 // L2CAP Connection-Oriented Channels in LE Credit-Based Flow-Control Mode - CBM
646 //
647 
648 /**
649  * @brief Register L2CAP service in LE Credit-Based Flow-Control Mode
650  * @note MTU and initial credits are specified in l2cap_cbm_accept_connection(..) call
651  * @param packet_handler
652  * @param psm
653  * @param security_level
654  */
655 uint8_t l2cap_cbm_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level);
656 
657 /**
658  * @brief Unregister L2CAP service in LE Credit-Based Flow-Control Mode
659  * @param psm
660  */
661 
662 uint8_t l2cap_cbm_unregister_service(uint16_t psm);
663 
664 /*
665  * @brief Accept incoming connection LE Credit-Based Flow-Control Mode
666  * @param local_cid             L2CAP Channel Identifier
667  * @param receive_buffer        buffer used for reassembly of L2CAP LE Information Frames into service data unit (SDU) with given MTU
668  * @param receive_buffer_size   buffer size equals MTU
669  * @param initial_credits       Number of initial credits provided to peer or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
670  */
671 
672 uint8_t l2cap_cbm_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits);
673 
674 /**
675  * @brief Deecline connection in LE Credit-Based Flow-Control Mode
676  * @param local_cid             L2CAP Channel Identifier
677  * @param result                result, see L2CAP_CBM_CONNECTION_RESULT_SUCCESS in bluetooth.h
678  */
679 
680 uint8_t l2cap_cbm_decline_connection(uint16_t local_cid, uint16_t result);
681 
682 /**
683  * @brief Create outgoing channel in LE Credit-Based Flow-Control Mode
684  * @param packet_handler        Packet handler for this connection
685  * @param con_handle            HCI Connection Handle, LE transport
686  * @param psm                   Service PSM to connect to
687  * @param receive_buffer        buffer used for reassembly of L2CAP LE Information Frames into service data unit (SDU) with given MTU
688  * @param receive_buffer_size   buffer size equals MTU
689  * @param initial_credits       Number of initial credits provided to peer or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
690  * @param security_level        Minimum required security level
691  * @param out_local_cid         L2CAP LE Channel Identifier is stored here
692  */
693 uint8_t l2cap_cbm_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
694     uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level,
695     uint16_t * out_local_cid);
696 
697 /**
698  * @brief Provide credits for channel in LE Credit-Based Flow-Control Mode
699  * @param local_cid             L2CAP Channel Identifier
700  * @param credits               Number additional credits for peer
701  */
702 uint8_t l2cap_cbm_provide_credits(uint16_t local_cid, uint16_t credits);
703 
704 //
705 // L2CAP Connection-Oriented Channels in Enhanced Credit-Based Flow-Control Mode - ECBM
706 //
707 
708 /**
709  * @brief Register L2CAP service in Enhanced Credit-Based Flow-Control Mode
710  * @note MTU and initial credits are specified in l2cap_enhanced_accept_connection(..) call
711  * @param packet_handler
712  * @param psm
713  * @param min_remote_mtu
714  * @param security_level
715  * @oaram authorization_required
716  * @return status
717  */
718 uint8_t l2cap_ecbm_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t min_remote_mtu,
719                                     gap_security_level_t security_level, bool authorization_required);
720 
721 /**
722  * @brief Unregister L2CAP service in Enhanced Credit-Based Flow-Control Mode
723  * @param psm
724  * @return status
725  */
726 
727 uint8_t l2cap_ecbm_unregister_service(uint16_t psm);
728 
729 /**
730  * @brief Set Minimal MPS for channel in Enhanced Credit-Based Flow-Control Mode
731  * @param mps_min
732  */
733 void l2cap_ecbm_mps_set_min(uint16_t mps_min);
734 
735 /**
736  * @brief Set Minimal MPS for channel in Enhanced Credit-Based Flow-Control Mode
737  * @param mps_max
738  */
739 void l2cap_ecbm_mps_set_max(uint16_t mps_max);
740 
741 /**
742  * @brief Create outgoing channel in Enhanced Credit-Based Flow-Control Mode
743  * @note receive_buffer points to an array of receive buffers with num_channels elements
744  * @note out_local_cid points to an array where CID is stored with num_channel elements
745  * @param packet_handler        Packet handler for this connection
746  * @param con_handle            HCI Connection Handle
747  * @param security_level        Minimum required security level
748  * @param psm                   Service PSM to connect to
749  * @param num_channels          number of channels to create
750  * @param initial_credits       Number of initial credits provided to peer per channel or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
751  * @param receive_buffer_size   buffer size equals MTU
752  * @param receive_buffers       Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
753  * @param out_local_cids        Array of L2CAP Channel Identifiers is stored here on success
754  * @return status
755  */
756 uint8_t l2cap_ecbm_create_channels(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
757                                        gap_security_level_t security_level,
758                                        uint16_t psm, uint8_t num_channels, uint16_t initial_credits, uint16_t receive_buffer_size,
759                                        uint8_t ** receive_buffers, uint16_t * out_local_cids);
760 
761 /**
762  * @brief  Accept incoming connection Enhanced Credit-Based Flow-Control Mode
763  * @param local_cid            from L2CAP_EVENT_INCOMING_DATA_CONNECTION
764  * @param num_channels
765  * @param initial_credits      Number of initial credits provided to peer per channel or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
766  * @param receive_buffer_size
767  * @param receive_buffers      Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
768  * @param out_local_cids       Array of L2CAP Channel Identifiers is stored here on success
769  * @return status
770  */
771 uint8_t l2cap_ecbm_accept_channels(uint16_t local_cid, uint8_t num_channels, uint16_t initial_credits,
772                                             uint16_t receive_buffer_size, uint8_t ** receive_buffers, uint16_t * out_local_cids);
773 /**
774  * @brief Decline connection in Enhanced Credit-Based Flow-Control Mode
775  * @param local_cid           from L2CAP_EVENT_INCOMING_DATA_CONNECTION
776  * @param result              See L2CAP_ECBM_CONNECTION_RESULT_ALL_SUCCESS in bluetooth.h
777  * @return status
778  */
779 uint8_t l2cap_ecbm_decline_channels(uint16_t local_cid, uint16_t result);
780 
781 /**
782  * @brief Provide credits for channel in Enhanced Credit-Based Flow-Control Mode
783  * @param local_cid             L2CAP Channel Identifier
784  * @param credits               Number additional credits for peer
785  * @return status
786  */
787 uint8_t l2cap_ecbm_provide_credits(uint16_t local_cid, uint16_t credits);
788 
789 /**
790  * @brief Request emission of L2CAP_EVENT_ECBM_CAN_SEND_NOW as soon as possible
791  * @note L2CAP_EVENT_ECBM_CAN_SEND_NOW might be emitted during call to this function
792  *       so packet handler should be ready to handle it
793  * @param local_cid             L2CAP Channel Identifier
794  * @return status
795  */
796 uint8_t l2cap_ecbm_request_can_send_now_event(uint16_t local_cid);
797 
798 /**
799  * @brief Reconfigure MPS/MTU of local channels
800  * @param num_cids
801  * @param local_cids            array of local_cids to reconfigure
802  * @param receive_buffer_size   buffer size equals MTU
803  * @param receive_buffers       Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
804  * @return status
805  */
806 uint8_t l2cap_ecbm_reconfigure_channels(uint8_t num_cids, uint16_t * local_cids, int16_t receive_buffer_size, uint8_t ** receive_buffers);
807 
808 /**
809  * @brief Trigger pending connection responses after pairing completed
810  * @note Must be called after receiving an SM_PAIRING_COMPLETE event, will be removed eventually
811  * @param con_handle
812  */
813 void l2cap_ecbm_trigger_pending_connection_responses(hci_con_handle_t con_handle);
814 
815 /**
816  * @brief De-Init L2CAP
817  */
818 void l2cap_deinit(void);
819 
820 /* API_END */
821 
822 
823 // @deprecated - please use l2cap_ertm_create_channel
824 uint8_t l2cap_create_ertm_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm,  l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size, uint16_t * out_local_cid);
825 
826 // @deprecated - please use l2cap_ertm_accept_connection
827 uint8_t l2cap_accept_ertm_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size);
828 
829 // @deprecated - please use l2cap_cbm_register_service
830 uint8_t l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level);
831 
832 // @deprecated - please use l2cap_cbm_unregister_service
833 uint8_t l2cap_le_unregister_service(uint16_t psm);
834 
835 // @deprecated - please use l2cap_cbm_accept_connection
836 uint8_t l2cap_le_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits);
837 
838 // @deprecated - please use l2cap_cbm_decline_connection
839 uint8_t l2cap_le_decline_connection(uint16_t local_cid);
840 
841 // @deprecated - please use l2cap_cbm_create_channel
842 uint8_t l2cap_le_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
843                                 uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level,
844                                 uint16_t * out_local_cid);
845 
846 // @deprecated - please use l2cap_cbm_provide_credits
847 uint8_t l2cap_le_provide_credits(uint16_t local_cid, uint16_t credits);
848 
849 // @deprecated - please use l2cap_can_send_now
850 bool l2cap_le_can_send_now(uint16_t local_cid);
851 
852 // @deprecated - please use l2cap_request_can_send_now_event
853 uint8_t l2cap_le_request_can_send_now_event(uint16_t local_cid);
854 
855 // @deprecated - please use l2cap_send
856 uint8_t l2cap_le_send_data(uint16_t local_cid, const uint8_t * data, uint16_t size);
857 
858 // @deprecated - please use l2cap_disconnect
859 uint8_t l2cap_le_disconnect(uint16_t local_cid);
860 
861 
862 #if defined __cplusplus
863 }
864 #endif
865 
866 #endif // L2CAP_H
867