xref: /btstack/src/l2cap.c (revision a0c35809ae94716d17ab9719a45751d19000a139)
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
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15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
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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
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33  * Please inquire about commercial licensing options at
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36  */
37 
38 /*
39  *  l2cap.c
40  *
41  *  Logical Link Control and Adaption Protocl (L2CAP)
42  *
43  *  Created by Matthias Ringwald on 5/16/09.
44  */
45 
46 #include "l2cap.h"
47 #include "hci.h"
48 #include "hci_dump.h"
49 #include "debug.h"
50 #include "btstack_memory.h"
51 
52 #include <stdarg.h>
53 #include <string.h>
54 
55 #include <stdio.h>
56 
57 // nr of buffered acl packets in outgoing queue to get max performance
58 #define NR_BUFFERED_ACL_PACKETS 3
59 
60 // used to cache l2cap rejects, echo, and informational requests
61 #define NR_PENDING_SIGNALING_RESPONSES 3
62 
63 // offsets for L2CAP SIGNALING COMMANDS
64 #define L2CAP_SIGNALING_COMMAND_CODE_OFFSET   0
65 #define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET  1
66 #define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2
67 #define L2CAP_SIGNALING_COMMAND_DATA_OFFSET   4
68 
69 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
70 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size);
71 
72 // used to cache l2cap rejects, echo, and informational requests
73 static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES];
74 static int signaling_responses_pending;
75 
76 static linked_list_t l2cap_channels;
77 static linked_list_t l2cap_services;
78 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler;
79 static int new_credits_blocked = 0;
80 
81 static btstack_packet_handler_t attribute_protocol_packet_handler;
82 static btstack_packet_handler_t security_protocol_packet_handler;
83 static uint8_t require_security_level2_for_outgoing_sdp;
84 
85 // prototypes
86 static void l2cap_finialize_channel_close(l2cap_channel_t *channel);
87 static l2cap_service_t * l2cap_get_service(uint16_t psm);
88 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status);
89 static void l2cap_emit_channel_closed(l2cap_channel_t *channel);
90 static void l2cap_emit_connection_request(l2cap_channel_t *channel);
91 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel);
92 
93 
94 void l2cap_init(){
95     new_credits_blocked = 0;
96     signaling_responses_pending = 0;
97 
98     l2cap_channels = NULL;
99     l2cap_services = NULL;
100 
101     packet_handler = null_packet_handler;
102     attribute_protocol_packet_handler = NULL;
103     security_protocol_packet_handler = NULL;
104 
105     require_security_level2_for_outgoing_sdp = 0;
106 
107     //
108     // register callback with HCI
109     //
110     hci_register_packet_handler(&l2cap_packet_handler);
111     hci_connectable_control(0); // no services yet
112 }
113 
114 
115 /** Register L2CAP packet handlers */
116 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
117 }
118 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){
119     packet_handler = handler;
120 }
121 
122 //  notify client/protocol handler
123 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){
124     if (channel->packet_handler) {
125         (* (channel->packet_handler))(type, channel->local_cid, data, size);
126     } else {
127         (*packet_handler)(channel->connection, type, channel->local_cid, data, size);
128     }
129 }
130 
131 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) {
132     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",
133              status, bd_addr_to_str(channel->address), channel->handle, channel->psm,
134              channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu, channel->flush_timeout);
135     uint8_t event[23];
136     event[0] = L2CAP_EVENT_CHANNEL_OPENED;
137     event[1] = sizeof(event) - 2;
138     event[2] = status;
139     bt_flip_addr(&event[3], channel->address);
140     bt_store_16(event,  9, channel->handle);
141     bt_store_16(event, 11, channel->psm);
142     bt_store_16(event, 13, channel->local_cid);
143     bt_store_16(event, 15, channel->remote_cid);
144     bt_store_16(event, 17, channel->local_mtu);
145     bt_store_16(event, 19, channel->remote_mtu);
146     bt_store_16(event, 21, channel->flush_timeout);
147     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
148     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
149 }
150 
151 void l2cap_emit_channel_closed(l2cap_channel_t *channel) {
152     log_info("L2CAP_EVENT_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid);
153     uint8_t event[4];
154     event[0] = L2CAP_EVENT_CHANNEL_CLOSED;
155     event[1] = sizeof(event) - 2;
156     bt_store_16(event, 2, channel->local_cid);
157     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
158     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
159 }
160 
161 void l2cap_emit_connection_request(l2cap_channel_t *channel) {
162     log_info("L2CAP_EVENT_INCOMING_CONNECTION addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x",
163              bd_addr_to_str(channel->address), channel->handle,  channel->psm, channel->local_cid, channel->remote_cid);
164     uint8_t event[16];
165     event[0] = L2CAP_EVENT_INCOMING_CONNECTION;
166     event[1] = sizeof(event) - 2;
167     bt_flip_addr(&event[2], channel->address);
168     bt_store_16(event,  8, channel->handle);
169     bt_store_16(event, 10, channel->psm);
170     bt_store_16(event, 12, channel->local_cid);
171     bt_store_16(event, 14, channel->remote_cid);
172     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
173     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
174 }
175 
176 void l2cap_emit_connection_parameter_update_response(uint16_t handle, uint16_t result){
177     uint8_t event[6];
178     event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE;
179     event[1] = 4;
180     bt_store_16(event, 2, handle);
181     bt_store_16(event, 4, result);
182     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
183     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, event, sizeof(event));
184 }
185 
186 static void l2cap_emit_service_registered(void *connection, uint8_t status, uint16_t psm){
187     log_info("L2CAP_EVENT_SERVICE_REGISTERED status 0x%x psm 0x%x", status, psm);
188     uint8_t event[5];
189     event[0] = L2CAP_EVENT_SERVICE_REGISTERED;
190     event[1] = sizeof(event) - 2;
191     event[2] = status;
192     bt_store_16(event, 3, psm);
193     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
194     (*packet_handler)(connection, HCI_EVENT_PACKET, 0, event, sizeof(event));
195 }
196 
197 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) {
198 
199     log_info("L2CAP_EVENT_CREDITS local_cid 0x%x credits %u", channel->local_cid, credits);
200     // track credits
201     channel->packets_granted += credits;
202 
203     uint8_t event[5];
204     event[0] = L2CAP_EVENT_CREDITS;
205     event[1] = sizeof(event) - 2;
206     bt_store_16(event, 2, channel->local_cid);
207     event[4] = credits;
208     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
209     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
210 }
211 
212 void l2cap_block_new_credits(uint8_t blocked){
213     new_credits_blocked = blocked;
214 }
215 
216 void l2cap_hand_out_credits(void){
217 
218     if (new_credits_blocked) return;    // we're told not to. used by daemon
219 
220     linked_list_iterator_t it;
221     linked_list_iterator_init(&it, &l2cap_channels);
222     while (linked_list_iterator_has_next(&it)){
223         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
224         if (!hci_number_free_acl_slots_for_handle(channel->handle)) return;
225         if (channel->state != L2CAP_STATE_OPEN) continue;
226         if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) {
227             l2cap_emit_credits(channel, 1);
228         }
229     }
230 }
231 
232 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){
233     linked_list_iterator_t it;
234     linked_list_iterator_init(&it, &l2cap_channels);
235     while (linked_list_iterator_has_next(&it)){
236         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
237         if ( channel->local_cid == local_cid) {
238             return channel;
239         }
240     }
241     return NULL;
242 }
243 
244 int  l2cap_can_send_packet_now(uint16_t local_cid){
245     l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid);
246     if (!channel) return 0;
247     if (!channel->packets_granted) return 0;
248     return hci_can_send_acl_packet_now(channel->handle);
249 }
250 
251 // @deprecated
252 int l2cap_can_send_connectionless_packet_now(void){
253     // TODO provide real handle
254     return l2cap_can_send_fixed_channel_packet_now(0x1234);
255 }
256 
257 int  l2cap_can_send_fixed_channel_packet_now(uint16_t handle){
258     return hci_can_send_acl_packet_now(handle);
259 }
260 
261 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){
262     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
263     if (channel) {
264         return channel->remote_mtu;
265     }
266     return 0;
267 }
268 
269 static l2cap_channel_t * l2cap_channel_for_rtx_timer(timer_source_t * ts){
270     linked_list_iterator_t it;
271     linked_list_iterator_init(&it, &l2cap_channels);
272     while (linked_list_iterator_has_next(&it)){
273         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
274         if ( &channel->rtx == ts) {
275             return channel;
276         }
277     }
278     return NULL;
279 }
280 
281 static void l2cap_rtx_timeout(timer_source_t * ts){
282     l2cap_channel_t * channel = l2cap_channel_for_rtx_timer(ts);
283     if (!ts) return;
284 
285     log_info("l2cap_rtx_timeout for local cid 0x%02x", channel->local_cid);
286 
287     // "When terminating the channel, it is not necessary to send a L2CAP_DisconnectReq
288     //  and enter WAIT_DISCONNECT state. Channels can be transitioned directly to the CLOSED state."
289     // notify client
290     l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_RTX_TIMEOUT);
291 
292     // discard channel
293     // no need to stop timer here, it is removed from list during timer callback
294     linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
295     btstack_memory_l2cap_channel_free(channel);
296 }
297 
298 static void l2cap_stop_rtx(l2cap_channel_t * channel){
299     log_info("l2cap_stop_rtx for local cid 0x%02x", channel->local_cid);
300     run_loop_remove_timer(&channel->rtx);
301 }
302 
303 static void l2cap_start_rtx(l2cap_channel_t * channel){
304     l2cap_stop_rtx(channel);
305     log_info("l2cap_start_rtx for local cid 0x%02x", channel->local_cid);
306     run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
307     run_loop_set_timer(&channel->rtx, L2CAP_RTX_TIMEOUT_MS);
308     run_loop_add_timer(&channel->rtx);
309 }
310 
311 static void l2cap_start_ertx(l2cap_channel_t * channel){
312     log_info("l2cap_start_ertx for local cid 0x%02x", channel->local_cid);
313     l2cap_stop_rtx(channel);
314     run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
315     run_loop_set_timer(&channel->rtx, L2CAP_ERTX_TIMEOUT_MS);
316     run_loop_add_timer(&channel->rtx);
317 }
318 
319 void l2cap_require_security_level_2_for_outgoing_sdp(){
320     require_security_level2_for_outgoing_sdp = 1;
321 }
322 
323 static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm){
324     return (psm == PSM_SDP) && (!require_security_level2_for_outgoing_sdp);
325 }
326 
327 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
328 
329     if (!hci_can_send_acl_packet_now(handle)){
330         log_info("l2cap_send_signaling_packet, cannot send");
331         return BTSTACK_ACL_BUFFERS_FULL;
332     }
333 
334     // log_info("l2cap_send_signaling_packet type %u", cmd);
335     hci_reserve_packet_buffer();
336     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
337     va_list argptr;
338     va_start(argptr, identifier);
339     uint16_t len = l2cap_create_signaling_classic(acl_buffer, handle, cmd, identifier, argptr);
340     va_end(argptr);
341     // log_info("l2cap_send_signaling_packet con %u!", handle);
342     return hci_send_acl_packet_buffer(len);
343 }
344 
345 #ifdef HAVE_BLE
346 int l2cap_send_le_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
347 
348     if (!hci_can_send_acl_packet_now(handle)){
349         log_info("l2cap_send_signaling_packet, cannot send");
350         return BTSTACK_ACL_BUFFERS_FULL;
351     }
352 
353     // log_info("l2cap_send_signaling_packet type %u", cmd);
354     hci_reserve_packet_buffer();
355     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
356     va_list argptr;
357     va_start(argptr, identifier);
358     uint16_t len = l2cap_create_signaling_le(acl_buffer, handle, cmd, identifier, argptr);
359     va_end(argptr);
360     // log_info("l2cap_send_signaling_packet con %u!", handle);
361     return hci_send_acl_packet_buffer(len);
362 }
363 #endif
364 
365 uint8_t *l2cap_get_outgoing_buffer(void){
366     return hci_get_outgoing_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes
367 }
368 
369 int l2cap_reserve_packet_buffer(void){
370     return hci_reserve_packet_buffer();
371 }
372 
373 void l2cap_release_packet_buffer(void){
374     hci_release_packet_buffer();
375 }
376 
377 
378 int l2cap_send_prepared(uint16_t local_cid, uint16_t len){
379 
380     if (!hci_is_packet_buffer_reserved()){
381         log_error("l2cap_send_prepared called without reserving packet first");
382         return BTSTACK_ACL_BUFFERS_FULL;
383     }
384 
385     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
386     if (!channel) {
387         log_error("l2cap_send_prepared no channel for cid 0x%02x", local_cid);
388         return -1;   // TODO: define error
389     }
390 
391     if (channel->packets_granted == 0){
392         log_error("l2cap_send_prepared cid 0x%02x, no credits!", local_cid);
393         return -1;  // TODO: define error
394     }
395 
396     if (!hci_can_send_prepared_acl_packet_now(channel->handle)){
397         log_info("l2cap_send_prepared cid 0x%02x, cannot send", local_cid);
398         return BTSTACK_ACL_BUFFERS_FULL;
399     }
400 
401     --channel->packets_granted;
402 
403     log_debug("l2cap_send_prepared cid 0x%02x, handle %u, 1 credit used, credits left %u;",
404                   local_cid, channel->handle, channel->packets_granted);
405 
406     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
407 
408     int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
409 
410     // 0 - Connection handle : PB=pb : BC=00
411     bt_store_16(acl_buffer, 0, channel->handle | (pb << 12) | (0 << 14));
412     // 2 - ACL length
413     bt_store_16(acl_buffer, 2,  len + 4);
414     // 4 - L2CAP packet length
415     bt_store_16(acl_buffer, 4,  len + 0);
416     // 6 - L2CAP channel DEST
417     bt_store_16(acl_buffer, 6, channel->remote_cid);
418     // send
419     int err = hci_send_acl_packet_buffer(len+8);
420 
421     l2cap_hand_out_credits();
422 
423     return err;
424 }
425 
426 int l2cap_send_prepared_connectionless(uint16_t handle, uint16_t cid, uint16_t len){
427 
428     if (!hci_is_packet_buffer_reserved()){
429         log_error("l2cap_send_prepared_connectionless called without reserving packet first");
430         return BTSTACK_ACL_BUFFERS_FULL;
431     }
432 
433     if (!hci_can_send_prepared_acl_packet_now(handle)){
434         log_info("l2cap_send_prepared_connectionless handle 0x%02x, cid 0x%02x, cannot send", handle, cid);
435         return BTSTACK_ACL_BUFFERS_FULL;
436     }
437 
438     log_debug("l2cap_send_prepared_connectionless handle %u, cid 0x%02x", handle, cid);
439 
440     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
441 
442     int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
443 
444     // 0 - Connection handle : PB=pb : BC=00
445     bt_store_16(acl_buffer, 0, handle | (pb << 12) | (0 << 14));
446     // 2 - ACL length
447     bt_store_16(acl_buffer, 2,  len + 4);
448     // 4 - L2CAP packet length
449     bt_store_16(acl_buffer, 4,  len + 0);
450     // 6 - L2CAP channel DEST
451     bt_store_16(acl_buffer, 6, cid);
452     // send
453     int err = hci_send_acl_packet_buffer(len+8);
454 
455     l2cap_hand_out_credits();
456 
457     return err;
458 }
459 
460 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){
461 
462     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
463     if (!channel) {
464         log_error("l2cap_send_internal no channel for cid 0x%02x", local_cid);
465         return -1;   // TODO: define error
466     }
467 
468     if (len > channel->remote_mtu){
469         log_error("l2cap_send_internal cid 0x%02x, data length exceeds remote MTU.", local_cid);
470         return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU;
471     }
472 
473     if (!hci_can_send_acl_packet_now(channel->handle)){
474         log_info("l2cap_send_internal cid 0x%02x, cannot send", local_cid);
475         return BTSTACK_ACL_BUFFERS_FULL;
476     }
477 
478     hci_reserve_packet_buffer();
479     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
480 
481     memcpy(&acl_buffer[8], data, len);
482 
483     return l2cap_send_prepared(local_cid, len);
484 }
485 
486 int l2cap_send_connectionless(uint16_t handle, uint16_t cid, uint8_t *data, uint16_t len){
487 
488     if (!hci_can_send_acl_packet_now(handle)){
489         log_info("l2cap_send_internal cid 0x%02x, cannot send", cid);
490         return BTSTACK_ACL_BUFFERS_FULL;
491     }
492 
493     hci_reserve_packet_buffer();
494     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
495 
496     memcpy(&acl_buffer[8], data, len);
497 
498     return l2cap_send_prepared_connectionless(handle, cid, len);
499 }
500 
501 int l2cap_send_echo_request(uint16_t handle, uint8_t *data, uint16_t len){
502     return l2cap_send_signaling_packet(handle, ECHO_REQUEST, 0x77, len, data);
503 }
504 
505 static inline void channelStateVarSetFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
506     channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var | flag);
507 }
508 
509 static inline void channelStateVarClearFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
510     channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var & ~flag);
511 }
512 
513 
514 
515 // MARK: L2CAP_RUN
516 // process outstanding signaling tasks
517 void l2cap_run(void){
518 
519     // check pending signaling responses
520     while (signaling_responses_pending){
521 
522         hci_con_handle_t handle = signaling_responses[0].handle;
523 
524         if (!hci_can_send_acl_packet_now(handle)) break;
525 
526         uint8_t  sig_id = signaling_responses[0].sig_id;
527         uint16_t infoType = signaling_responses[0].data;    // INFORMATION_REQUEST
528         uint16_t result   = signaling_responses[0].data;    // CONNECTION_REQUEST, COMMAND_REJECT
529         uint8_t  response_code = signaling_responses[0].code;
530 
531         // remove first item before sending (to avoid sending response mutliple times)
532         signaling_responses_pending--;
533         int i;
534         for (i=0; i < signaling_responses_pending; i++){
535             memcpy(&signaling_responses[i], &signaling_responses[i+1], sizeof(l2cap_signaling_response_t));
536         }
537 
538         switch (response_code){
539             case CONNECTION_REQUEST:
540                 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0);
541                 // also disconnect if result is 0x0003 - security blocked
542                 if (result == 0x0003){
543                     hci_disconnect_security_block(handle);
544                 }
545                 break;
546             case ECHO_REQUEST:
547                 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL);
548                 break;
549             case INFORMATION_REQUEST:
550                 switch (infoType){
551                     case 1: { // Connectionless MTU
552                         uint16_t connectionless_mtu = hci_max_acl_data_packet_length();
553                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(connectionless_mtu), &connectionless_mtu);
554                         break;
555                     }
556                     case 2: { // Extended Features Supported
557                         // extended features request supported, only supporing fixed channel map
558                         uint32_t features = 0x80;
559                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(features), &features);
560                         break;
561                     }
562                     case 3: { // Fixed Channels Supported
563                         uint8_t map[8];
564                         memset(map, 0, 8);
565                         map[0] = 0x01;  // L2CAP Signaling Channel
566                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(map), &map);
567                         break;
568                     }
569                     default:
570                         // all other types are not supported
571                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL);
572                         break;
573                 }
574                 break;
575             case COMMAND_REJECT:
576                 l2cap_send_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
577 #ifdef HAVE_BLE
578             case COMMAND_REJECT_LE:
579                 l2cap_send_le_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
580                 break;
581 #endif
582             default:
583                 // should not happen
584                 break;
585         }
586     }
587 
588     uint8_t  config_options[4];
589     linked_list_iterator_t it;
590     linked_list_iterator_init(&it, &l2cap_channels);
591     while (linked_list_iterator_has_next(&it)){
592 
593         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
594         // log_info("l2cap_run: state %u, var 0x%02x", channel->state, channel->state_var);
595         switch (channel->state){
596 
597             case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
598             case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT:
599                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
600                 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND) {
601                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND);
602                     l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 1, 0);
603                 }
604                 break;
605 
606             case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
607                 if (!hci_can_send_command_packet_now()) break;
608                 // send connection request - set state first
609                 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE;
610                 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch
611                 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1);
612                 break;
613 
614             case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE:
615                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
616                 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, channel->reason, 0);
617                 // discard channel - l2cap_finialize_channel_close without sending l2cap close event
618                 l2cap_stop_rtx(channel);
619                 linked_list_iterator_remove(&it);
620                 btstack_memory_l2cap_channel_free(channel);
621                 break;
622 
623             case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT:
624                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
625                 channel->state = L2CAP_STATE_CONFIG;
626                 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
627                 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0);
628                 break;
629 
630             case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST:
631                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
632                 // success, start l2cap handshake
633                 channel->local_sig_id = l2cap_next_sig_id();
634                 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP;
635                 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid);
636                 l2cap_start_rtx(channel);
637                 break;
638 
639             case L2CAP_STATE_CONFIG:
640                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
641                 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){
642                     uint16_t flags = 0;
643                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
644                     if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT) {
645                         flags = 1;
646                     } else {
647                         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP);
648                     }
649                     if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID){
650                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_UNKNOWN_OPTIONS, 0, NULL);
651                     } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU){
652                         config_options[0] = 1; // MTU
653                         config_options[1] = 2; // len param
654                         bt_store_16( (uint8_t*)&config_options, 2, channel->remote_mtu);
655                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 4, &config_options);
656                         channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
657                     } else {
658                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 0, NULL);
659                     }
660                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
661                 }
662                 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){
663                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
664                     channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ);
665                     channel->local_sig_id = l2cap_next_sig_id();
666                     config_options[0] = 1; // MTU
667                     config_options[1] = 2; // len param
668                     bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu);
669                     l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options);
670                     l2cap_start_rtx(channel);
671                 }
672                 if (l2cap_channel_ready_for_open(channel)){
673                     channel->state = L2CAP_STATE_OPEN;
674                     l2cap_emit_channel_opened(channel, 0);  // success
675                     l2cap_emit_credits(channel, 1);
676                 }
677                 break;
678 
679             case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE:
680                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
681                 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid);
682                 // 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 :)
683                 l2cap_finialize_channel_close(channel);  // -- remove from list
684                 break;
685 
686             case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
687                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
688                 channel->local_sig_id = l2cap_next_sig_id();
689                 channel->state = L2CAP_STATE_WAIT_DISCONNECT;
690                 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid);
691                 break;
692             default:
693                 break;
694         }
695     }
696 
697 #ifdef HAVE_BLE
698     // send l2cap con paramter update if necessary
699     hci_connections_get_iterator(&it);
700     while(linked_list_iterator_has_next(&it)){
701         hci_connection_t * connection = (hci_connection_t *) linked_list_iterator_next(&it);
702         int result;
703 
704         switch (connection->le_con_parameter_update_state){
705             case CON_PARAMETER_UPDATE_SEND_RESPONSE:
706                 result = 0;
707                 break;
708             case CON_PARAMETER_UPDATE_DENY:
709                 result = 1;
710                 break;
711             default:
712                 result = -1;
713                 break;
714         }
715         if (result < 0) break;
716 
717         if (!hci_can_send_acl_packet_now(connection->con_handle)) break;
718         hci_reserve_packet_buffer();
719         uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
720         connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_CHANGE_HCI_CON_PARAMETERS;
721         uint16_t len = l2cap_le_create_connection_parameter_update_response(acl_buffer, connection->con_handle, 0);
722         hci_send_acl_packet_buffer(len);
723     }
724 #endif
725 
726 }
727 
728 uint16_t l2cap_max_mtu(void){
729     return HCI_ACL_PAYLOAD_SIZE - L2CAP_HEADER_SIZE;
730 }
731 
732 uint16_t l2cap_max_le_mtu(){
733     return l2cap_max_mtu();
734 }
735 
736 static void l2cap_handle_connection_complete(uint16_t handle, l2cap_channel_t * channel){
737     if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) {
738         log_info("l2cap_handle_connection_complete expected state");
739         // success, start l2cap handshake
740         channel->handle = handle;
741         channel->local_cid = l2cap_next_local_cid();
742         // check remote SSP feature first
743         channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES;
744     }
745 }
746 
747 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){
748     if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return;
749 
750     // we have been waiting for remote supported features, if both support SSP,
751     log_info("l2cap received remote supported features, sec_level_0_allowed for psm %u = %u", channel->psm, l2cap_security_level_0_allowed_for_PSM(channel->psm));
752     if (hci_ssp_supported_on_both_sides(channel->handle) && !l2cap_security_level_0_allowed_for_PSM(channel->psm)){
753         // request security level 2
754         channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE;
755         gap_request_security_level(channel->handle, LEVEL_2);
756         return;
757     }
758     // fine, go ahead
759     channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
760 }
761 
762 // open outgoing L2CAP channel
763 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler,
764                                    bd_addr_t address, uint16_t psm, uint16_t mtu){
765 
766     log_info("L2CAP_CREATE_CHANNEL_MTU addr %s psm 0x%x mtu %u", bd_addr_to_str(address), psm, mtu);
767 
768     // alloc structure
769     l2cap_channel_t * chan = btstack_memory_l2cap_channel_get();
770     if (!chan) {
771         // emit error event
772         l2cap_channel_t dummy_channel;
773         BD_ADDR_COPY(dummy_channel.address, address);
774         dummy_channel.psm = psm;
775         l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED);
776         return;
777     }
778     // Init memory (make valgrind happy)
779     memset(chan, 0, sizeof(l2cap_channel_t));
780     // limit local mtu to max acl packet length - l2cap header
781     if (mtu > l2cap_max_mtu()) {
782         mtu = l2cap_max_mtu();
783     }
784 
785     // fill in
786     BD_ADDR_COPY(chan->address, address);
787     chan->psm = psm;
788     chan->handle = 0;
789     chan->connection = connection;
790     chan->packet_handler = packet_handler;
791     chan->remote_mtu = L2CAP_MINIMAL_MTU;
792     chan->local_mtu = mtu;
793     chan->packets_granted = 0;
794 
795     // set initial state
796     chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION;
797     chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE;
798     chan->remote_sig_id = L2CAP_SIG_ID_INVALID;
799     chan->local_sig_id = L2CAP_SIG_ID_INVALID;
800     chan->required_security_level = LEVEL_0;
801 
802     // add to connections list
803     linked_list_add(&l2cap_channels, (linked_item_t *) chan);
804 
805     // check if hci connection is already usable
806     hci_connection_t * conn = hci_connection_for_bd_addr_and_type((bd_addr_t*)address, BD_ADDR_TYPE_CLASSIC);
807     if (conn){
808         log_info("l2cap_create_channel_internal, hci connection already exists");
809         l2cap_handle_connection_complete(conn->con_handle, chan);
810         // check ir remote supported fearures are already received
811         if (conn->bonding_flags & BONDING_RECEIVED_REMOTE_FEATURES) {
812             l2cap_handle_remote_supported_features_received(chan);
813         }
814     }
815 
816     l2cap_run();
817 }
818 
819 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){
820     log_info("L2CAP_DISCONNECT local_cid 0x%x reason 0x%x", local_cid, reason);
821     // find channel for local_cid
822     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
823     if (channel) {
824         channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST;
825     }
826     // process
827     l2cap_run();
828 }
829 
830 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){
831     linked_list_iterator_t it;
832     linked_list_iterator_init(&it, &l2cap_channels);
833     while (linked_list_iterator_has_next(&it)){
834         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
835         if ( BD_ADDR_CMP( channel->address, address) != 0) continue;
836         // channel for this address found
837         switch (channel->state){
838             case L2CAP_STATE_WAIT_CONNECTION_COMPLETE:
839             case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
840                 // failure, forward error code
841                 l2cap_emit_channel_opened(channel, status);
842                 // discard channel
843                 l2cap_stop_rtx(channel);
844                 linked_list_iterator_remove(&it);
845                 btstack_memory_l2cap_channel_free(channel);
846                 break;
847             default:
848                 break;
849         }
850     }
851 }
852 
853 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){
854     linked_list_iterator_t it;
855     linked_list_iterator_init(&it, &l2cap_channels);
856     while (linked_list_iterator_has_next(&it)){
857         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
858         if ( ! BD_ADDR_CMP( channel->address, address) ){
859             l2cap_handle_connection_complete(handle, channel);
860         }
861     }
862     // process
863     l2cap_run();
864 }
865 
866 void l2cap_event_handler(uint8_t *packet, uint16_t size){
867 
868     bd_addr_t address;
869     hci_con_handle_t handle;
870     linked_list_iterator_t it;
871     int hci_con_used;
872 
873     switch(packet[0]){
874 
875         // handle connection complete events
876         case HCI_EVENT_CONNECTION_COMPLETE:
877             bt_flip_addr(address, &packet[5]);
878             if (packet[2] == 0){
879                 handle = READ_BT_16(packet, 3);
880                 l2cap_handle_connection_success_for_addr(address, handle);
881             } else {
882                 l2cap_handle_connection_failed_for_addr(address, packet[2]);
883             }
884             break;
885 
886         // handle successful create connection cancel command
887         case HCI_EVENT_COMMAND_COMPLETE:
888             if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) {
889                 if (packet[5] == 0){
890                     bt_flip_addr(address, &packet[6]);
891                     // CONNECTION TERMINATED BY LOCAL HOST (0X16)
892                     l2cap_handle_connection_failed_for_addr(address, 0x16);
893                 }
894             }
895             l2cap_run();    // try sending signaling packets first
896             break;
897 
898         case HCI_EVENT_COMMAND_STATUS:
899             l2cap_run();    // try sending signaling packets first
900             break;
901 
902         // handle disconnection complete events
903         case HCI_EVENT_DISCONNECTION_COMPLETE:
904             // send l2cap disconnect events for all channels on this handle and free them
905             handle = READ_BT_16(packet, 3);
906             linked_list_iterator_init(&it, &l2cap_channels);
907             while (linked_list_iterator_has_next(&it)){
908                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
909                 if (channel->handle != handle) continue;
910                 l2cap_emit_channel_closed(channel);
911                 l2cap_stop_rtx(channel);
912                 linked_list_iterator_remove(&it);
913                 btstack_memory_l2cap_channel_free(channel);
914             }
915             break;
916 
917         case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS:
918             l2cap_run();    // try sending signaling packets first
919             l2cap_hand_out_credits();
920             break;
921 
922         // HCI Connection Timeouts
923         case L2CAP_EVENT_TIMEOUT_CHECK:
924             handle = READ_BT_16(packet, 2);
925             if (hci_authentication_active_for_handle(handle)) break;
926             hci_con_used = 0;
927             linked_list_iterator_init(&it, &l2cap_channels);
928             while (linked_list_iterator_has_next(&it)){
929                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
930                 if (channel->handle != handle) continue;
931                 hci_con_used = 1;
932                 break;
933             }
934             if (hci_con_used) break;
935             if (!hci_can_send_command_packet_now()) break;
936             hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection
937             break;
938 
939         case DAEMON_EVENT_HCI_PACKET_SENT:
940             linked_list_iterator_init(&it, &l2cap_channels);
941             while (linked_list_iterator_has_next(&it)){
942                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
943                 if (!channel->packet_handler) continue;
944                 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size);
945             }
946             if (attribute_protocol_packet_handler) {
947                 (*attribute_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
948             }
949             if (security_protocol_packet_handler) {
950                 (*security_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
951             }
952             break;
953 
954         case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE:
955             handle = READ_BT_16(packet, 3);
956             linked_list_iterator_init(&it, &l2cap_channels);
957             while (linked_list_iterator_has_next(&it)){
958                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
959                 if (channel->handle != handle) continue;
960                 l2cap_handle_remote_supported_features_received(channel);
961                 break;
962             }
963             break;
964 
965         case GAP_SECURITY_LEVEL:
966             handle = READ_BT_16(packet, 2);
967             log_info("l2cap - security level update");
968             linked_list_iterator_init(&it, &l2cap_channels);
969             while (linked_list_iterator_has_next(&it)){
970                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
971                 if (channel->handle != handle) continue;
972 
973                 log_info("l2cap - state %u", channel->state);
974 
975                 gap_security_level_t actual_level = packet[4];
976                 gap_security_level_t required_level = channel->required_security_level;
977 
978                 switch (channel->state){
979                     case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
980                         if (actual_level >= required_level){
981                             channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT;
982                             l2cap_emit_connection_request(channel);
983                         } else {
984                             channel->reason = 0x03; // security block
985                             channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
986                         }
987                         break;
988 
989                     case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE:
990                         if (actual_level >= required_level){
991                             channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
992                         } else {
993                             // disconnnect, authentication not good enough
994                             hci_disconnect_security_block(handle);
995                         }
996                         break;
997 
998                     default:
999                         break;
1000                 }
1001             }
1002             break;
1003 
1004         default:
1005             break;
1006     }
1007 
1008     // pass on: main packet handler, att and sm packet handlers
1009     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size);
1010     if (attribute_protocol_packet_handler){
1011         (*attribute_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
1012     }
1013     if (security_protocol_packet_handler) {
1014         (*security_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
1015     }
1016 
1017     l2cap_run();
1018 }
1019 
1020 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){
1021     channel->remote_sig_id = identifier;
1022     channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE;
1023     l2cap_run();
1024 }
1025 
1026 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){
1027     // Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused."
1028     if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) {
1029         signaling_responses[signaling_responses_pending].handle = handle;
1030         signaling_responses[signaling_responses_pending].code = code;
1031         signaling_responses[signaling_responses_pending].sig_id = sig_id;
1032         signaling_responses[signaling_responses_pending].data = data;
1033         signaling_responses_pending++;
1034         l2cap_run();
1035     }
1036 }
1037 
1038 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){
1039 
1040     // log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid);
1041     l2cap_service_t *service = l2cap_get_service(psm);
1042     if (!service) {
1043         // 0x0002 PSM not supported
1044         l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002);
1045         return;
1046     }
1047 
1048     hci_connection_t * hci_connection = hci_connection_for_handle( handle );
1049     if (!hci_connection) {
1050         //
1051         log_error("no hci_connection for handle %u", handle);
1052         return;
1053     }
1054 
1055     // reject connection (0x03 security block) and disconnect if both have SSP, connection is not encrypted and PSM != SDP
1056     if (  hci_ssp_supported_on_both_sides(handle)
1057     &&    gap_security_level(handle) == LEVEL_0
1058     &&   !l2cap_security_level_0_allowed_for_PSM(psm)){
1059 
1060         // 0x0003 Security Block
1061         l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0003);
1062         return;
1063     }
1064 
1065 
1066     // alloc structure
1067     // log_info("l2cap_handle_connection_request register channel");
1068     l2cap_channel_t * channel = btstack_memory_l2cap_channel_get();
1069     if (!channel){
1070         // 0x0004 No resources available
1071         l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004);
1072         return;
1073     }
1074     // Init memory (make valgrind happy)
1075     memset(channel, 0, sizeof(l2cap_channel_t));
1076     // fill in
1077     BD_ADDR_COPY(channel->address, hci_connection->address);
1078     channel->psm = psm;
1079     channel->handle = handle;
1080     channel->connection = service->connection;
1081     channel->packet_handler = service->packet_handler;
1082     channel->local_cid  = l2cap_next_local_cid();
1083     channel->remote_cid = source_cid;
1084     channel->local_mtu  = service->mtu;
1085     channel->remote_mtu = L2CAP_DEFAULT_MTU;
1086     channel->packets_granted = 0;
1087     channel->remote_sig_id = sig_id;
1088     channel->required_security_level = service->required_security_level;
1089 
1090     // limit local mtu to max acl packet length - l2cap header
1091     if (channel->local_mtu > l2cap_max_mtu()) {
1092         channel->local_mtu = l2cap_max_mtu();
1093     }
1094 
1095     // set initial state
1096     channel->state =     L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE;
1097     channel->state_var = L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND;
1098 
1099     // add to connections list
1100     linked_list_add(&l2cap_channels, (linked_item_t *) channel);
1101 
1102     // assert security requirements
1103     gap_request_security_level(handle, channel->required_security_level);
1104 }
1105 
1106 void l2cap_accept_connection_internal(uint16_t local_cid){
1107     log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid);
1108     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
1109     if (!channel) {
1110         log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid);
1111         return;
1112     }
1113 
1114     channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT;
1115 
1116     // process
1117     l2cap_run();
1118 }
1119 
1120 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){
1121     log_info("L2CAP_DECLINE_CONNECTION local_cid 0x%x, reason %x", local_cid, reason);
1122     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid);
1123     if (!channel) {
1124         log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid);
1125         return;
1126     }
1127     channel->state  = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
1128     channel->reason = reason;
1129     l2cap_run();
1130 }
1131 
1132 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){
1133 
1134     channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1135 
1136     uint16_t flags = READ_BT_16(command, 6);
1137     if (flags & 1) {
1138         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
1139     }
1140 
1141     // accept the other's configuration options
1142     uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
1143     uint16_t pos     = 8;
1144     while (pos < end_pos){
1145         uint8_t option_hint = command[pos] >> 7;
1146         uint8_t option_type = command[pos] & 0x7f;
1147         log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type);
1148         pos++;
1149         uint8_t length = command[pos++];
1150         // MTU { type(8): 1, len(8):2, MTU(16) }
1151         if (option_type == 1 && length == 2){
1152             channel->remote_mtu = READ_BT_16(command, pos);
1153             // log_info("l2cap cid 0x%02x, remote mtu %u", channel->local_cid, channel->remote_mtu);
1154             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
1155         }
1156         // Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)}
1157         if (option_type == 2 && length == 2){
1158             channel->flush_timeout = READ_BT_16(command, pos);
1159         }
1160         // check for unknown options
1161         if (option_hint == 0 && (option_type == 0 || option_type >= 0x07)){
1162             log_info("l2cap cid %u, unknown options", channel->local_cid);
1163             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID);
1164         }
1165         pos += length;
1166     }
1167 }
1168 
1169 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){
1170     // log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var);
1171     if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0;
1172     if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0;
1173     return 1;
1174 }
1175 
1176 
1177 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){
1178 
1179     uint8_t  code       = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
1180     uint8_t  identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1181     uint16_t result = 0;
1182 
1183     log_info("L2CAP signaling handler code %u, state %u", code, channel->state);
1184 
1185     // handle DISCONNECT REQUESTS seperately
1186     if (code == DISCONNECTION_REQUEST){
1187         switch (channel->state){
1188             case L2CAP_STATE_CONFIG:
1189             case L2CAP_STATE_OPEN:
1190             case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
1191             case L2CAP_STATE_WAIT_DISCONNECT:
1192                 l2cap_handle_disconnect_request(channel, identifier);
1193                 break;
1194 
1195             default:
1196                 // ignore in other states
1197                 break;
1198         }
1199         return;
1200     }
1201 
1202     // @STATEMACHINE(l2cap)
1203     switch (channel->state) {
1204 
1205         case L2CAP_STATE_WAIT_CONNECT_RSP:
1206             switch (code){
1207                 case CONNECTION_RESPONSE:
1208                     l2cap_stop_rtx(channel);
1209                     result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
1210                     switch (result) {
1211                         case 0:
1212                             // successful connection
1213                             channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1214                             channel->state = L2CAP_STATE_CONFIG;
1215                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
1216                             break;
1217                         case 1:
1218                             // connection pending. get some coffee, but start the ERTX
1219                             l2cap_start_ertx(channel);
1220                             break;
1221                         default:
1222                             // channel closed
1223                             channel->state = L2CAP_STATE_CLOSED;
1224                             // map l2cap connection response result to BTstack status enumeration
1225                             l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result);
1226 
1227                             // drop link key if security block
1228                             if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){
1229                                 hci_drop_link_key_for_bd_addr(&channel->address);
1230                             }
1231 
1232                             // discard channel
1233                             linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
1234                             btstack_memory_l2cap_channel_free(channel);
1235                             break;
1236                     }
1237                     break;
1238 
1239                 default:
1240                     //@TODO: implement other signaling packets
1241                     break;
1242             }
1243             break;
1244 
1245         case L2CAP_STATE_CONFIG:
1246             result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
1247             switch (code) {
1248                 case CONFIGURE_REQUEST:
1249                     channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
1250                     l2cap_signaling_handle_configure_request(channel, command);
1251                     if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){
1252                         // only done if continuation not set
1253                         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ);
1254                     }
1255                     break;
1256                 case CONFIGURE_RESPONSE:
1257                     l2cap_stop_rtx(channel);
1258                     switch (result){
1259                         case 0: // success
1260                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP);
1261                             break;
1262                         case 4: // pending
1263                             l2cap_start_ertx(channel);
1264                             break;
1265                         default:
1266                             // retry on negative result
1267                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
1268                             break;
1269                     }
1270                     break;
1271                 default:
1272                     break;
1273             }
1274             if (l2cap_channel_ready_for_open(channel)){
1275                 // for open:
1276                 channel->state = L2CAP_STATE_OPEN;
1277                 l2cap_emit_channel_opened(channel, 0);
1278                 l2cap_emit_credits(channel, 1);
1279             }
1280             break;
1281 
1282         case L2CAP_STATE_WAIT_DISCONNECT:
1283             switch (code) {
1284                 case DISCONNECTION_RESPONSE:
1285                     l2cap_finialize_channel_close(channel);
1286                     break;
1287                 default:
1288                     //@TODO: implement other signaling packets
1289                     break;
1290             }
1291             break;
1292 
1293         case L2CAP_STATE_CLOSED:
1294             // @TODO handle incoming requests
1295             break;
1296 
1297         case L2CAP_STATE_OPEN:
1298             //@TODO: implement other signaling packets, e.g. re-configure
1299             break;
1300         default:
1301             break;
1302     }
1303     // log_info("new state %u", channel->state);
1304 }
1305 
1306 
1307 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){
1308 
1309     // get code, signalind identifier and command len
1310     uint8_t code   = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
1311     uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1312 
1313     // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST
1314     if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){
1315         l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, L2CAP_REJ_CMD_UNKNOWN);
1316         return;
1317     }
1318 
1319     // general commands without an assigned channel
1320     switch(code) {
1321 
1322         case CONNECTION_REQUEST: {
1323             uint16_t psm =        READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1324             uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2);
1325             l2cap_handle_connection_request(handle, sig_id, psm, source_cid);
1326             return;
1327         }
1328 
1329         case ECHO_REQUEST:
1330             l2cap_register_signaling_response(handle, code, sig_id, 0);
1331             return;
1332 
1333         case INFORMATION_REQUEST: {
1334             uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1335             l2cap_register_signaling_response(handle, code, sig_id, infoType);
1336             return;
1337         }
1338 
1339         default:
1340             break;
1341     }
1342 
1343 
1344     // Get potential destination CID
1345     uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1346 
1347     // Find channel for this sig_id and connection handle
1348     linked_list_iterator_t it;
1349     linked_list_iterator_init(&it, &l2cap_channels);
1350     while (linked_list_iterator_has_next(&it)){
1351         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
1352         if (channel->handle != handle) continue;
1353         if (code & 1) {
1354             // match odd commands (responses) by previous signaling identifier
1355             if (channel->local_sig_id == sig_id) {
1356                 l2cap_signaling_handler_channel(channel, command);
1357                 break;
1358             }
1359         } else {
1360             // match even commands (requests) by local channel id
1361             if (channel->local_cid == dest_cid) {
1362                 l2cap_signaling_handler_channel(channel, command);
1363                 break;
1364             }
1365         }
1366     }
1367 }
1368 
1369 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){
1370 
1371     // Get Channel ID
1372     uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet);
1373     hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet);
1374 
1375     switch (channel_id) {
1376 
1377         case L2CAP_CID_SIGNALING: {
1378 
1379             uint16_t command_offset = 8;
1380             while (command_offset < size) {
1381 
1382                 // handle signaling commands
1383                 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]);
1384 
1385                 // increment command_offset
1386                 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
1387             }
1388             break;
1389         }
1390 
1391         case L2CAP_CID_ATTRIBUTE_PROTOCOL:
1392             if (attribute_protocol_packet_handler) {
1393                 (*attribute_protocol_packet_handler)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1394             }
1395             break;
1396 
1397         case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
1398             if (security_protocol_packet_handler) {
1399                 (*security_protocol_packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1400             }
1401             break;
1402 
1403         case L2CAP_CID_SIGNALING_LE: {
1404             switch (packet[8]){
1405                 case CONNECTION_PARAMETER_UPDATE_RESPONSE: {
1406                     uint16_t result = READ_BT_16(packet, 12);
1407                     l2cap_emit_connection_parameter_update_response(handle, result);
1408                     break;
1409                 }
1410                 case CONNECTION_PARAMETER_UPDATE_REQUEST: {
1411                     uint8_t event[10];
1412                     event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST;
1413                     event[1] = 8;
1414                     memcpy(&event[2], &packet[12], 8);
1415 
1416                     hci_connection_t * connection = hci_connection_for_handle(handle);
1417                     if (connection){
1418                         int update_parameter = 1;
1419                         le_connection_parameter_range_t existing_range = gap_le_get_connection_parameter_range();
1420                         uint16_t le_conn_interval_min = READ_BT_16(packet,12);
1421                         uint16_t le_conn_interval_max = READ_BT_16(packet,14);
1422                         uint16_t le_conn_latency = READ_BT_16(packet,16);
1423                         uint16_t le_supervision_timeout = READ_BT_16(packet,18);
1424 
1425                         if (le_conn_interval_min < existing_range.le_conn_interval_min) update_parameter = 0;
1426                         if (le_conn_interval_max > existing_range.le_conn_interval_max) update_parameter = 0;
1427 
1428                         if (le_conn_latency < existing_range.le_conn_latency_min) update_parameter = 0;
1429                         if (le_conn_latency > existing_range.le_conn_latency_max) update_parameter = 0;
1430 
1431                         if (le_supervision_timeout < existing_range.le_supervision_timeout_min) update_parameter = 0;
1432                         if (le_supervision_timeout > existing_range.le_supervision_timeout_max) update_parameter = 0;
1433 
1434                         if (update_parameter){
1435                             connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE;
1436                             connection->le_conn_interval_min = le_conn_interval_min;
1437                             connection->le_conn_interval_max = le_conn_interval_max;
1438                             connection->le_conn_latency = le_conn_latency;
1439                             connection->le_supervision_timeout = le_supervision_timeout;
1440                         } else {
1441                             connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY;
1442                         }
1443                     }
1444 
1445                     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1446                     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, event, sizeof(event));
1447 
1448                     break;
1449                 }
1450                 default: {
1451                     uint8_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1];
1452                     l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, L2CAP_REJ_CMD_UNKNOWN);
1453                     break;
1454                 }
1455             }
1456             break;
1457         }
1458 
1459         default: {
1460             // Find channel for this channel_id and connection handle
1461             l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id);
1462             if (channel) {
1463                 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1464             }
1465             break;
1466         }
1467     }
1468 }
1469 
1470 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
1471     switch (packet_type) {
1472         case HCI_EVENT_PACKET:
1473             l2cap_event_handler(packet, size);
1474             break;
1475         case HCI_ACL_DATA_PACKET:
1476             l2cap_acl_handler(packet, size);
1477             break;
1478         default:
1479             break;
1480     }
1481     l2cap_run();
1482 }
1483 
1484 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE
1485 void l2cap_finialize_channel_close(l2cap_channel_t *channel){
1486     channel->state = L2CAP_STATE_CLOSED;
1487     l2cap_emit_channel_closed(channel);
1488     // discard channel
1489     l2cap_stop_rtx(channel);
1490     linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
1491     btstack_memory_l2cap_channel_free(channel);
1492 }
1493 
1494 l2cap_service_t * l2cap_get_service(uint16_t psm){
1495     linked_list_iterator_t it;
1496     linked_list_iterator_init(&it, &l2cap_services);
1497     while (linked_list_iterator_has_next(&it)){
1498         l2cap_service_t * service = (l2cap_service_t *) linked_list_iterator_next(&it);
1499         if ( service->psm == psm){
1500             return service;
1501         };
1502     }
1503     return NULL;
1504 }
1505 
1506 void l2cap_register_service_internal(void *connection, btstack_packet_handler_t packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level){
1507 
1508     log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u connection %p", psm, mtu, connection);
1509 
1510     // check for alread registered psm
1511     // TODO: emit error event
1512     l2cap_service_t *service = l2cap_get_service(psm);
1513     if (service) {
1514         log_error("l2cap_register_service_internal: PSM %u already registered", psm);
1515         l2cap_emit_service_registered(connection, L2CAP_SERVICE_ALREADY_REGISTERED, psm);
1516         return;
1517     }
1518 
1519     // alloc structure
1520     // TODO: emit error event
1521     service = btstack_memory_l2cap_service_get();
1522     if (!service) {
1523         log_error("l2cap_register_service_internal: no memory for l2cap_service_t");
1524         l2cap_emit_service_registered(connection, BTSTACK_MEMORY_ALLOC_FAILED, psm);
1525         return;
1526     }
1527 
1528     // fill in
1529     service->psm = psm;
1530     service->mtu = mtu;
1531     service->connection = connection;
1532     service->packet_handler = packet_handler;
1533     service->required_security_level = security_level;
1534 
1535     // add to services list
1536     linked_list_add(&l2cap_services, (linked_item_t *) service);
1537 
1538     // enable page scan
1539     hci_connectable_control(1);
1540 
1541     // done
1542     l2cap_emit_service_registered(connection, 0, psm);
1543 }
1544 
1545 void l2cap_unregister_service_internal(void *connection, uint16_t psm){
1546 
1547     log_info("L2CAP_UNREGISTER_SERVICE psm 0x%x", psm);
1548 
1549     l2cap_service_t *service = l2cap_get_service(psm);
1550     if (!service) return;
1551     linked_list_remove(&l2cap_services, (linked_item_t *) service);
1552     btstack_memory_l2cap_service_free(service);
1553 
1554     // disable page scan when no services registered
1555     if (!linked_list_empty(&l2cap_services)) return;
1556     hci_connectable_control(0);
1557 }
1558 
1559 
1560 // Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol
1561 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id) {
1562     switch(channel_id){
1563         case L2CAP_CID_ATTRIBUTE_PROTOCOL:
1564             attribute_protocol_packet_handler = packet_handler;
1565             break;
1566         case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
1567             security_protocol_packet_handler = packet_handler;
1568             break;
1569     }
1570 }
1571 
1572 #ifdef HAVE_BLE
1573 
1574 // Request LE connection parameter update
1575 int l2cap_le_request_connection_parameter_update(uint16_t handle, uint16_t interval_min, uint16_t interval_max, uint16_t slave_latency, uint16_t timeout_multiplier){
1576     if (!hci_can_send_acl_packet_now(handle)){
1577         log_info("l2cap_send_signaling_packet, cannot send");
1578         return BTSTACK_ACL_BUFFERS_FULL;
1579     }
1580     // log_info("l2cap_send_signaling_packet type %u", cmd);
1581     hci_reserve_packet_buffer();
1582     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
1583     uint16_t len = l2cap_le_create_connection_parameter_update_request(acl_buffer, handle, interval_min, interval_max, slave_latency, timeout_multiplier);
1584     return hci_send_acl_packet_buffer(len);
1585 }
1586 #endif
1587 
1588