xref: /btstack/src/l2cap.h (revision c824d78c0a34df89b57d535abafcc7dacf30bb06)
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
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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  remote_mps;
274 
275     // credits for outgoing traffic
276     uint16_t credits_outgoing;
277 
278     // number of packets remote will be granted
279     uint16_t new_credits_incoming;
280 
281     // credits for incoming traffic
282     uint16_t credits_incoming;
283 
284     // automatic credits incoming
285     bool automatic_credits;
286 
287 #ifdef ENABLE_L2CAP_ENHANCED_CREDIT_BASED_FLOW_CONTROL_MODE
288     uint8_t cid_index;
289     uint8_t num_cids;
290 #endif
291 
292 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE
293 
294     // l2cap channel mode: basic or enhanced retransmission mode
295     l2cap_channel_mode_t mode;
296 
297     // local mps = size of rx/tx buffers
298     uint16_t local_mps;
299 
300     // retransmission timer
301     btstack_timer_source_t retransmission_timer;
302 
303     // monitor timer
304     btstack_timer_source_t monitor_timer;
305 
306     // local/remote config options
307     uint16_t local_retransmission_timeout_ms;
308     uint16_t local_monitor_timeout_ms;
309 
310     uint16_t remote_retransmission_timeout_ms;
311     uint16_t remote_monitor_timeout_ms;
312 
313     uint8_t remote_tx_window_size;
314 
315     uint8_t local_max_transmit;
316     uint8_t remote_max_transmit;
317 
318     // if ertm is not mandatory, allow fallback to L2CAP Basic Mode - flag
319     uint8_t ertm_mandatory;
320 
321     // Frame Chech Sequence (crc16) is present in both directions
322     uint8_t fcs_option;
323 
324     // sender: max num of stored outgoing frames
325     uint8_t num_tx_buffers;
326 
327     // sender: num stored outgoing frames
328     uint8_t num_stored_tx_frames;
329 
330     // sender: number of unacknowledeged I-Frames - frames have been sent, but not acknowledged yet
331     uint8_t unacked_frames;
332 
333     // sender: buffer index of oldest packet
334     uint8_t tx_read_index;
335 
336     // sender: buffer index to store next tx packet
337     uint8_t tx_write_index;
338 
339     // sender: buffer index of packet to send next
340     uint8_t tx_send_index;
341 
342     // sender: next seq nr used for sending
343     uint8_t next_tx_seq;
344 
345     // sender: selective retransmission requested
346     uint8_t srej_active;
347 
348 
349     // receiver: max num out-of-order packets // tx_window
350     uint8_t num_rx_buffers;
351 
352     // receiver: buffer index of to store packet with delta = 1
353     uint8_t rx_store_index;
354 
355     // receiver: value of tx_seq in next expected i-frame
356     uint8_t expected_tx_seq;
357 
358     // receiver: request transmission with tx_seq = req_seq and ack up to and including req_seq
359     uint8_t req_seq;
360 
361     // receiver: local busy condition
362     uint8_t local_busy;
363 
364     // receiver: send RR frame with optional final flag set - flag
365     uint8_t send_supervisor_frame_receiver_ready;
366 
367     // receiver: send RR frame with poll bit set
368     uint8_t send_supervisor_frame_receiver_ready_poll;
369 
370     // receiver: send RNR frame - flag
371     uint8_t send_supervisor_frame_receiver_not_ready;
372 
373     // receiver: send REJ frame - flag
374     uint8_t send_supervisor_frame_reject;
375 
376     // receiver: send SREJ frame - flag
377     uint8_t send_supervisor_frame_selective_reject;
378 
379     // set final bit after poll packet with poll bit was received
380     uint8_t set_final_bit_after_packet_with_poll_bit_set;
381 
382     // receiver: meta data for out-of-order frames
383     l2cap_ertm_rx_packet_state_t * rx_packets_state;
384 
385     // sender: retransmission state
386     l2cap_ertm_tx_packet_state_t * tx_packets_state;
387 
388     // receiver: reassemly pos
389     uint16_t reassembly_pos;
390 
391     // receiver: reassemly sdu length
392     uint16_t reassembly_sdu_length;
393 
394     // receiver: eassembly buffer
395     uint8_t * reassembly_buffer;
396 
397     // receiver: num_rx_buffers of size local_mps
398     uint8_t * rx_packets_data;
399 
400     // sender: num_tx_buffers of size local_mps
401     uint8_t * tx_packets_data;
402 
403 #endif
404 } l2cap_channel_t;
405 
406 // info regarding potential connections
407 typedef struct {
408     // linked list - assert: first field
409     btstack_linked_item_t    item;
410 
411     // service id
412     uint16_t  psm;
413 
414     // max local mtu for basic mode, min remote mtu for enhanced credit-based flow-control mode
415     uint16_t mtu;
416 
417     // internal connection
418     btstack_packet_handler_t packet_handler;
419 
420     // required security level
421     gap_security_level_t required_security_level;
422 
423 } l2cap_service_t;
424 
425 
426 typedef struct l2cap_signaling_response {
427     hci_con_handle_t handle;
428     uint8_t  sig_id;
429     uint8_t  code;
430     uint16_t cid;  // source cid for CONNECTION REQUEST
431     uint16_t data; // infoType for INFORMATION REQUEST, result for CONNECTION REQUEST and COMMAND UNKNOWN
432 } l2cap_signaling_response_t;
433 
434 
435 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id);
436 bool l2cap_can_send_fixed_channel_packet_now(hci_con_handle_t con_handle, uint16_t channel_id);
437 void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t channel_id);
438 uint8_t l2cap_send_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint8_t *data, uint16_t len);
439 uint8_t l2cap_send_prepared_connectionless(hci_con_handle_t con_handle, uint16_t cid, uint16_t len);
440 
441 // PTS Testing
442 int l2cap_send_echo_request(hci_con_handle_t con_handle, uint8_t *data, uint16_t len);
443 void l2cap_require_security_level_2_for_outgoing_sdp(void);
444 
445 // Used by RFCOMM - similar to l2cap_can-send_packet_now but does not check if outgoing buffer is reserved
446 bool l2cap_can_send_prepared_packet_now(uint16_t local_cid);
447 
448 /* API_START */
449 
450 //
451 // PSM numbers from https://www.bluetooth.com/specifications/assigned-numbers/logical-link-control
452 //
453 #define PSM_SDP           BLUETOOTH_PROTOCOL_SDP
454 #define PSM_RFCOMM        BLUETOOTH_PROTOCOL_RFCOMM
455 #define PSM_BNEP          BLUETOOTH_PROTOCOL_BNEP
456 // @TODO: scrape PSMs Bluetooth SIG site and put in bluetooth_psm.h or bluetooth_l2cap.h
457 #define PSM_HID_CONTROL   0x11
458 #define PSM_HID_INTERRUPT 0x13
459 #define PSM_ATT           0x1f
460 #define PSM_IPSP          0x23
461 
462 /**
463  * @brief Set up L2CAP and register L2CAP with HCI layer.
464  */
465 void l2cap_init(void);
466 
467 /**
468  * @brief Add event packet handler for LE Connection Parameter Update events
469  */
470 void l2cap_add_event_handler(btstack_packet_callback_registration_t * callback_handler);
471 
472 /**
473  * @brief Remove event packet handler.
474  */
475 void l2cap_remove_event_handler(btstack_packet_callback_registration_t * callback_handler);
476 
477 /**
478  * @brief Get max MTU for Classic connections based on btstack configuration
479  */
480 uint16_t l2cap_max_mtu(void);
481 
482 /**
483  * @brief Get max MTU for LE connections based on btstack configuration
484  */
485 uint16_t l2cap_max_le_mtu(void);
486 
487 /**
488 * @brief Set the max MTU for LE connections, if not set l2cap_max_mtu() will be used.
489 */
490 void l2cap_set_max_le_mtu(uint16_t max_mtu);
491 
492 /**
493  * @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary.
494  * @param packet_handler
495  * @param address
496  * @param psm
497  * @param mtu
498  * @param local_cid
499  * @return status
500  */
501 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);
502 
503 /**
504  * @brief Disconnects L2CAP channel with given identifier.
505  * @param local_cid
506  * @return status ERROR_CODE_SUCCESS if successful or L2CAP_LOCAL_CID_DOES_NOT_EXIST
507  */
508 uint8_t l2cap_disconnect(uint16_t local_cid);
509 
510 /**
511  * @brief Queries the maximal transfer unit (MTU) for L2CAP channel with given identifier.
512  */
513 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid);
514 
515 /**
516  * @brief Sends L2CAP data packet to the channel with given identifier.
517  * @note For channel in credit-based flow control mode, data needs to stay valid until .. event
518  * @param local_cid
519  * @param data to send
520  * @param len of data
521  * @return status
522  */
523 uint8_t l2cap_send(uint16_t local_cid, const uint8_t *data, uint16_t len);
524 
525 /**
526  * @brief Registers L2CAP service with given PSM and MTU, and assigns a packet handler.
527  * @param packet_handler
528  * @param psm
529  * @param mtu
530  * @param security_level
531  * @return status ERROR_CODE_SUCCESS if successful, otherwise L2CAP_SERVICE_ALREADY_REGISTERED or BTSTACK_MEMORY_ALLOC_FAILED
532  */
533 uint8_t l2cap_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level);
534 
535 /**
536  * @brief Unregisters L2CAP service with given PSM.
537  */
538 uint8_t l2cap_unregister_service(uint16_t psm);
539 
540 /**
541  * @brief Accepts incoming L2CAP connection.
542  */
543 void l2cap_accept_connection(uint16_t local_cid);
544 
545 /**
546  * @brief Deny incoming L2CAP connection.
547  */
548 void l2cap_decline_connection(uint16_t local_cid);
549 
550 /**
551  * @brief Check if outgoing buffer is available and that there's space on the Bluetooth module
552  * @return true if packet can be sent
553  */
554 bool l2cap_can_send_packet_now(uint16_t local_cid);
555 
556 /**
557  * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible
558  * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function
559  *       so packet handler should be ready to handle it
560  * @param local_cid
561  * @return status
562  */
563 uint8_t l2cap_request_can_send_now_event(uint16_t local_cid);
564 
565 /**
566  * @brief Reserve outgoing buffer
567  * @note Only for L2CAP Basic Mode Channels
568  * @return true on success
569  */
570 bool l2cap_reserve_packet_buffer(void);
571 
572 /**
573  * @brief Get outgoing buffer and prepare data.
574  * @note Only for L2CAP Basic Mode Channels
575  */
576 uint8_t *l2cap_get_outgoing_buffer(void);
577 
578 /**
579  * @brief Send L2CAP packet prepared in outgoing buffer to channel
580  * @note Only for L2CAP Basic Mode Channels
581  */
582 uint8_t l2cap_send_prepared(uint16_t local_cid, uint16_t len);
583 
584 /**
585  * @brief Release outgoing buffer (only needed if l2cap_send_prepared is not called)
586  * @note Only for L2CAP Basic Mode Channels
587  */
588 void l2cap_release_packet_buffer(void);
589 
590 //
591 // Connection-Oriented Channels in Enhanced Retransmission Mode - ERTM
592 //
593 
594 /**
595  * @brief Creates L2CAP channel to the PSM of a remote device with baseband address using Enhanced Retransmission Mode.
596  *        A new baseband connection will be initiated if necessary.
597  * @param packet_handler
598  * @param address
599  * @param psm
600  * @param ertm_config
601  * @param buffer to store reassembled rx packet, out-of-order packets and unacknowledged outgoing packets with their tretransmission timers
602  * @param size of buffer
603  * @param local_cid
604  * @return status
605  */
606 uint8_t l2cap_ertm_create_channel(btstack_packet_handler_t packet_handler, bd_addr_t address, uint16_t psm,
607                                   l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size, uint16_t * out_local_cid);
608 
609 /**
610  * @brief Accepts incoming L2CAP connection for Enhanced Retransmission Mode
611  * @param local_cid
612  * @param ertm_config
613  * @param buffer to store reassembled rx packet, out-of-order packets and unacknowledged outgoing packets with their tretransmission timers
614  * @param size of buffer
615  * @return status
616  */
617 uint8_t l2cap_ertm_accept_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size);
618 
619 /**
620  * @brief Deny incoming incoming L2CAP connection for Enhanced Retransmission Mode
621  * @param local_cid
622  * @return status
623  */
624 uint8_t l2cap_ertm_decline_connection(uint16_t local_cid);
625 
626 /**
627  * @brief ERTM Set channel as busy.
628  * @note Can be cleared by l2cap_ertm_set_ready
629  * @param local_cid
630  * @return status
631  */
632 uint8_t l2cap_ertm_set_busy(uint16_t local_cid);
633 
634 /**
635  * @brief ERTM Set channel as ready
636  * @note Used after l2cap_ertm_set_busy
637  * @param local_cid
638  * @return status
639  */
640 uint8_t l2cap_ertm_set_ready(uint16_t local_cid);
641 
642 
643 //
644 // L2CAP Connection-Oriented Channels in LE Credit-Based Flow-Control Mode - CBM
645 //
646 
647 /**
648  * @brief Register L2CAP service in LE Credit-Based Flow-Control Mode
649  * @note MTU and initial credits are specified in l2cap_cbm_accept_connection(..) call
650  * @param packet_handler
651  * @param psm
652  * @param security_level
653  */
654 uint8_t l2cap_cbm_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level);
655 
656 /**
657  * @brief Unregister L2CAP service in LE Credit-Based Flow-Control Mode
658  * @param psm
659  */
660 
661 uint8_t l2cap_cbm_unregister_service(uint16_t psm);
662 
663 /*
664  * @brief Accept incoming connection LE Credit-Based Flow-Control Mode
665  * @param local_cid             L2CAP Channel Identifier
666  * @param receive_buffer        buffer used for reassembly of L2CAP LE Information Frames into service data unit (SDU) with given MTU
667  * @param receive_buffer_size   buffer size equals MTU
668  * @param initial_credits       Number of initial credits provided to peer or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
669  */
670 
671 uint8_t l2cap_cbm_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits);
672 
673 /**
674  * @brief Deecline connection in LE Credit-Based Flow-Control Mode
675  * @param local_cid             L2CAP Channel Identifier
676  * @param result                result, see L2CAP_CBM_CONNECTION_RESULT_SUCCESS in bluetooth.h
677  */
678 
679 uint8_t l2cap_cbm_decline_connection(uint16_t local_cid, uint16_t result);
680 
681 /**
682  * @brief Create outgoing channel in LE Credit-Based Flow-Control Mode
683  * @param packet_handler        Packet handler for this connection
684  * @param con_handle            HCI Connection Handle, LE transport
685  * @param psm                   Service PSM to connect to
686  * @param receive_buffer        buffer used for reassembly of L2CAP LE Information Frames into service data unit (SDU) with given MTU
687  * @param receive_buffer_size   buffer size equals MTU
688  * @param initial_credits       Number of initial credits provided to peer or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
689  * @param security_level        Minimum required security level
690  * @param out_local_cid         L2CAP LE Channel Identifier is stored here
691  */
692 uint8_t l2cap_cbm_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
693     uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level,
694     uint16_t * out_local_cid);
695 
696 /**
697  * @brief Provide credits for channel in LE Credit-Based Flow-Control Mode
698  * @param local_cid             L2CAP Channel Identifier
699  * @param credits               Number additional credits for peer
700  */
701 uint8_t l2cap_cbm_provide_credits(uint16_t local_cid, uint16_t credits);
702 
703 //
704 // L2CAP Connection-Oriented Channels in Enhanced Credit-Based Flow-Control Mode - ECBM
705 //
706 
707 /**
708  * @brief Register L2CAP service in Enhanced Credit-Based Flow-Control Mode
709  * @note MTU and initial credits are specified in l2cap_enhanced_accept_connection(..) call
710  * @param packet_handler
711  * @param psm
712  * @param min_remote_mtu
713  * @param security_level
714  * @return status
715  */
716 uint8_t l2cap_ecbm_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t min_remote_mtu, gap_security_level_t security_level);
717 
718 /**
719  * @brief Unregister L2CAP service in Enhanced Credit-Based Flow-Control Mode
720  * @param psm
721  * @return status
722  */
723 
724 uint8_t l2cap_ecbm_unregister_service(uint16_t psm);
725 
726 /**
727  * @brief Set Minimal MPS for channel in Enhanced Credit-Based Flow-Control Mode
728  * @param mps_min
729  */
730 void l2cap_ecbm_mps_set_min(uint16_t mps_min);
731 
732 /**
733  * @brief Set Minimal MPS for channel in Enhanced Credit-Based Flow-Control Mode
734  * @param mps_max
735  */
736 void l2cap_ecbm_mps_set_max(uint16_t mps_max);
737 
738 /**
739  * @brief Create outgoing channel in Enhanced Credit-Based Flow-Control Mode
740  * @note receive_buffer points to an array of receive buffers with num_channels elements
741  * @note out_local_cid points to an array where CID is stored with num_channel elements
742  * @param packet_handler        Packet handler for this connection
743  * @param con_handle            HCI Connection Handle
744  * @param security_level        Minimum required security level
745  * @param psm                   Service PSM to connect to
746  * @param num_channels          number of channels to create
747  * @param initial_credits       Number of initial credits provided to peer per channel or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
748  * @param receive_buffer_size   buffer size equals MTU
749  * @param receive_buffers       Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
750  * @param out_local_cids        Array of L2CAP Channel Identifiers is stored here on success
751  * @return status
752  */
753 uint8_t l2cap_ecbm_create_channels(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
754                                        gap_security_level_t security_level,
755                                        uint16_t psm, uint8_t num_channels, uint16_t initial_credits, uint16_t receive_buffer_size,
756                                        uint8_t ** receive_buffers, uint16_t * out_local_cids);
757 
758 /**
759  * @brief  Accept incoming connection Enhanced Credit-Based Flow-Control Mode
760  * @param local_cid            from L2CAP_EVENT_INCOMING_DATA_CONNECTION
761  * @param num_channels
762  * @param initial_credits      Number of initial credits provided to peer per channel or L2CAP_LE_AUTOMATIC_CREDITS to enable automatic credits
763  * @param receive_buffer_size
764  * @param receive_buffers      Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
765  * @param out_local_cids       Array of L2CAP Channel Identifiers is stored here on success
766  * @return status
767  */
768 uint8_t l2cap_ecbm_accept_channels(uint16_t local_cid, uint8_t num_channels, uint16_t initial_credits,
769                                             uint16_t receive_buffer_size, uint8_t ** receive_buffers, uint16_t * out_local_cids);
770 /**
771  * @brief Decline connection in Enhanced Credit-Based Flow-Control Mode
772  * @param local_cid           from L2CAP_EVENT_INCOMING_DATA_CONNECTION
773  * @param result              See L2CAP_ECBM_CONNECTION_RESULT_ALL_SUCCESS in bluetooth.h
774  * @return status
775  */
776 uint8_t l2cap_ecbm_decline_channels(uint16_t local_cid, uint16_t result);
777 
778 /**
779  * @brief Provide credits for channel in Enhanced Credit-Based Flow-Control Mode
780  * @param local_cid             L2CAP Channel Identifier
781  * @param credits               Number additional credits for peer
782  * @return status
783  */
784 uint8_t l2cap_ecbm_provide_credits(uint16_t local_cid, uint16_t credits);
785 
786 /**
787  * @brief Request emission of L2CAP_EVENT_ECBM_CAN_SEND_NOW as soon as possible
788  * @note L2CAP_EVENT_ECBM_CAN_SEND_NOW might be emitted during call to this function
789  *       so packet handler should be ready to handle it
790  * @param local_cid             L2CAP Channel Identifier
791  * @return status
792  */
793 uint8_t l2cap_ecbm_request_can_send_now_event(uint16_t local_cid);
794 
795 /**
796  * @brief Reconfigure MPS/MTU of local channels
797  * @param num_cids
798  * @param local_cids            array of local_cids to reconfigure
799  * @param receive_buffer_size   buffer size equals MTU
800  * @param receive_buffers       Array of buffers used for reassembly of L2CAP Information Frames into service data unit (SDU) with given MTU
801  * @return status
802  */
803 uint8_t l2cap_ecbm_reconfigure_channels(uint8_t num_cids, uint16_t * local_cids, int16_t receive_buffer_size, uint8_t ** receive_buffers);
804 
805 /**
806  * @brief De-Init L2CAP
807  */
808 void l2cap_deinit(void);
809 
810 /* API_END */
811 
812 
813 // @deprecated - please use l2cap_ertm_create_channel
814 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);
815 
816 // @deprecated - please use l2cap_ertm_accept_connection
817 uint8_t l2cap_accept_ertm_connection(uint16_t local_cid, l2cap_ertm_config_t * ertm_contig, uint8_t * buffer, uint32_t size);
818 
819 // @deprecated - please use l2cap_cbm_register_service
820 uint8_t l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm, gap_security_level_t security_level);
821 
822 // @deprecated - please use l2cap_cbm_unregister_service
823 uint8_t l2cap_le_unregister_service(uint16_t psm);
824 
825 // @deprecated - please use l2cap_cbm_accept_connection
826 uint8_t l2cap_le_accept_connection(uint16_t local_cid, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits);
827 
828 // @deprecated - please use l2cap_cbm_decline_connection
829 uint8_t l2cap_le_decline_connection(uint16_t local_cid);
830 
831 // @deprecated - please use l2cap_cbm_create_channel
832 uint8_t l2cap_le_create_channel(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle,
833                                 uint16_t psm, uint8_t * receive_sdu_buffer, uint16_t mtu, uint16_t initial_credits, gap_security_level_t security_level,
834                                 uint16_t * out_local_cid);
835 
836 // @deprecated - please use l2cap_cbm_decline_connection
837 uint8_t l2cap_le_provide_credits(uint16_t local_cid, uint16_t credits);
838 
839 // @deprecated - please use l2cap_cbm_can_send_now
840 bool l2cap_le_can_send_now(uint16_t local_cid);
841 
842 // @deprecated - please use l2cap_cbm_request_can_send_now_event
843 uint8_t l2cap_le_request_can_send_now_event(uint16_t local_cid);
844 
845 // @deprecated - please use l2cap_send_data
846 uint8_t l2cap_le_send_data(uint16_t local_cid, const uint8_t * data, uint16_t size);
847 
848 // @deprecated - please use l2cap_disconnect
849 uint8_t l2cap_le_disconnect(uint16_t local_cid);
850 
851 // @deprecated - please use l2cap_can_send_now
852 bool l2cap_cbm_can_send_now(uint16_t local_cid);
853 
854 // @deprecated - please use l2cap_request_can_send_now_event
855 uint8_t l2cap_cbm_request_can_send_now_event(uint16_t local_cid);
856 
857 
858 #if defined __cplusplus
859 }
860 #endif
861 
862 #endif // L2CAP_H
863