xref: /btstack/src/l2cap.c (revision d5814ca7a939167d6299da0134b368962bece148)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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31  * SUCH DAMAGE.
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33  * Please inquire about commercial licensing options at
34  * [email protected]
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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 linked_list_t l2cap_le_channels;
79 static linked_list_t l2cap_le_services;
80 static void (*packet_handler) (void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) = null_packet_handler;
81 static int new_credits_blocked = 0;
82 
83 static btstack_packet_handler_t attribute_protocol_packet_handler;
84 static btstack_packet_handler_t security_protocol_packet_handler;
85 static btstack_packet_handler_t connectionless_channel_packet_handler;
86 static uint8_t require_security_level2_for_outgoing_sdp;
87 
88 // prototypes
89 static void l2cap_finialize_channel_close(l2cap_channel_t *channel);
90 static inline l2cap_service_t * l2cap_get_service(uint16_t psm);
91 static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status);
92 static void l2cap_emit_channel_closed(l2cap_channel_t *channel);
93 static void l2cap_emit_connection_request(l2cap_channel_t *channel);
94 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel);
95 
96 
97 void l2cap_init(void){
98     new_credits_blocked = 0;
99     signaling_responses_pending = 0;
100 
101     l2cap_channels = NULL;
102     l2cap_services = NULL;
103     l2cap_le_services = NULL;
104     l2cap_le_channels = NULL;
105 
106     packet_handler = null_packet_handler;
107     attribute_protocol_packet_handler = NULL;
108     security_protocol_packet_handler = NULL;
109     connectionless_channel_packet_handler = NULL;
110 
111     require_security_level2_for_outgoing_sdp = 0;
112 
113     //
114     // register callback with HCI
115     //
116     hci_register_packet_handler(&l2cap_packet_handler);
117     hci_connectable_control(0); // no services yet
118 }
119 
120 
121 /** Register L2CAP packet handlers */
122 static void null_packet_handler(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
123 }
124 void l2cap_register_packet_handler(void (*handler)(void * connection, uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){
125     packet_handler = handler;
126 }
127 
128 //  notify client/protocol handler
129 void l2cap_dispatch(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){
130     if (channel->packet_handler) {
131         (* (channel->packet_handler))(type, channel->local_cid, data, size);
132     } else {
133         (*packet_handler)(channel->connection, type, channel->local_cid, data, size);
134     }
135 }
136 
137 void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) {
138     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",
139              status, bd_addr_to_str(channel->address), channel->handle, channel->psm,
140              channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu, channel->flush_timeout);
141     uint8_t event[23];
142     event[0] = L2CAP_EVENT_CHANNEL_OPENED;
143     event[1] = sizeof(event) - 2;
144     event[2] = status;
145     bt_flip_addr(&event[3], channel->address);
146     bt_store_16(event,  9, channel->handle);
147     bt_store_16(event, 11, channel->psm);
148     bt_store_16(event, 13, channel->local_cid);
149     bt_store_16(event, 15, channel->remote_cid);
150     bt_store_16(event, 17, channel->local_mtu);
151     bt_store_16(event, 19, channel->remote_mtu);
152     bt_store_16(event, 21, channel->flush_timeout);
153     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
154     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
155 }
156 
157 void l2cap_emit_channel_closed(l2cap_channel_t *channel) {
158     log_info("L2CAP_EVENT_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid);
159     uint8_t event[4];
160     event[0] = L2CAP_EVENT_CHANNEL_CLOSED;
161     event[1] = sizeof(event) - 2;
162     bt_store_16(event, 2, channel->local_cid);
163     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
164     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
165 }
166 
167 void l2cap_emit_connection_request(l2cap_channel_t *channel) {
168     log_info("L2CAP_EVENT_INCOMING_CONNECTION addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x",
169              bd_addr_to_str(channel->address), channel->handle,  channel->psm, channel->local_cid, channel->remote_cid);
170     uint8_t event[16];
171     event[0] = L2CAP_EVENT_INCOMING_CONNECTION;
172     event[1] = sizeof(event) - 2;
173     bt_flip_addr(&event[2], channel->address);
174     bt_store_16(event,  8, channel->handle);
175     bt_store_16(event, 10, channel->psm);
176     bt_store_16(event, 12, channel->local_cid);
177     bt_store_16(event, 14, channel->remote_cid);
178     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
179     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
180 }
181 
182 void l2cap_emit_connection_parameter_update_response(uint16_t handle, uint16_t result){
183     uint8_t event[6];
184     event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE;
185     event[1] = 4;
186     bt_store_16(event, 2, handle);
187     bt_store_16(event, 4, result);
188     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
189     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, event, sizeof(event));
190 }
191 
192 static void l2cap_emit_service_registered(void *connection, uint8_t status, uint16_t psm){
193     log_info("L2CAP_EVENT_SERVICE_REGISTERED status 0x%x psm 0x%x", status, psm);
194     uint8_t event[5];
195     event[0] = L2CAP_EVENT_SERVICE_REGISTERED;
196     event[1] = sizeof(event) - 2;
197     event[2] = status;
198     bt_store_16(event, 3, psm);
199     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
200     (*packet_handler)(connection, HCI_EVENT_PACKET, 0, event, sizeof(event));
201 }
202 
203 void l2cap_emit_credits(l2cap_channel_t *channel, uint8_t credits) {
204 
205     log_info("L2CAP_EVENT_CREDITS local_cid 0x%x credits %u", channel->local_cid, credits);
206     // track credits
207     channel->packets_granted += credits;
208 
209     uint8_t event[5];
210     event[0] = L2CAP_EVENT_CREDITS;
211     event[1] = sizeof(event) - 2;
212     bt_store_16(event, 2, channel->local_cid);
213     event[4] = credits;
214     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
215     l2cap_dispatch(channel, HCI_EVENT_PACKET, event, sizeof(event));
216 }
217 
218 void l2cap_block_new_credits(uint8_t blocked){
219     new_credits_blocked = blocked;
220 }
221 
222 void l2cap_hand_out_credits(void){
223 
224     if (new_credits_blocked) return;    // we're told not to. used by daemon
225 
226     linked_list_iterator_t it;
227     linked_list_iterator_init(&it, &l2cap_channels);
228     while (linked_list_iterator_has_next(&it)){
229         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
230         if (channel->state != L2CAP_STATE_OPEN) continue;
231         if (!hci_number_free_acl_slots_for_handle(channel->handle)) return;
232         if (hci_number_outgoing_packets(channel->handle) < NR_BUFFERED_ACL_PACKETS && channel->packets_granted == 0) {
233             l2cap_emit_credits(channel, 1);
234         }
235     }
236 }
237 
238 l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){
239     linked_list_iterator_t it;
240     linked_list_iterator_init(&it, &l2cap_channels);
241     while (linked_list_iterator_has_next(&it)){
242         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
243         if ( channel->local_cid == local_cid) {
244             return channel;
245         }
246     }
247     return NULL;
248 }
249 
250 int  l2cap_can_send_packet_now(uint16_t local_cid){
251     l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid);
252     if (!channel) return 0;
253     if (!channel->packets_granted) return 0;
254     return hci_can_send_acl_packet_now(channel->handle);
255 }
256 
257 // @deprecated
258 int l2cap_can_send_connectionless_packet_now(void){
259     // TODO provide real handle
260     return l2cap_can_send_fixed_channel_packet_now(0x1234);
261 }
262 
263 int  l2cap_can_send_fixed_channel_packet_now(uint16_t handle){
264     return hci_can_send_acl_packet_now(handle);
265 }
266 
267 uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){
268     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
269     if (channel) {
270         return channel->remote_mtu;
271     }
272     return 0;
273 }
274 
275 static l2cap_channel_t * l2cap_channel_for_rtx_timer(timer_source_t * ts){
276     linked_list_iterator_t it;
277     linked_list_iterator_init(&it, &l2cap_channels);
278     while (linked_list_iterator_has_next(&it)){
279         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
280         if ( &channel->rtx == ts) {
281             return channel;
282         }
283     }
284     return NULL;
285 }
286 
287 static void l2cap_rtx_timeout(timer_source_t * ts){
288     l2cap_channel_t * channel = l2cap_channel_for_rtx_timer(ts);
289     if (!ts) return;
290 
291     log_info("l2cap_rtx_timeout for local cid 0x%02x", channel->local_cid);
292 
293     // "When terminating the channel, it is not necessary to send a L2CAP_DisconnectReq
294     //  and enter WAIT_DISCONNECT state. Channels can be transitioned directly to the CLOSED state."
295     // notify client
296     l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_RTX_TIMEOUT);
297 
298     // discard channel
299     // no need to stop timer here, it is removed from list during timer callback
300     linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
301     btstack_memory_l2cap_channel_free(channel);
302 }
303 
304 static void l2cap_stop_rtx(l2cap_channel_t * channel){
305     log_info("l2cap_stop_rtx for local cid 0x%02x", channel->local_cid);
306     run_loop_remove_timer(&channel->rtx);
307 }
308 
309 static void l2cap_start_rtx(l2cap_channel_t * channel){
310     l2cap_stop_rtx(channel);
311     log_info("l2cap_start_rtx for local cid 0x%02x", channel->local_cid);
312     run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
313     run_loop_set_timer(&channel->rtx, L2CAP_RTX_TIMEOUT_MS);
314     run_loop_add_timer(&channel->rtx);
315 }
316 
317 static void l2cap_start_ertx(l2cap_channel_t * channel){
318     log_info("l2cap_start_ertx for local cid 0x%02x", channel->local_cid);
319     l2cap_stop_rtx(channel);
320     run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
321     run_loop_set_timer(&channel->rtx, L2CAP_ERTX_TIMEOUT_MS);
322     run_loop_add_timer(&channel->rtx);
323 }
324 
325 void l2cap_require_security_level_2_for_outgoing_sdp(void){
326     require_security_level2_for_outgoing_sdp = 1;
327 }
328 
329 static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm){
330     return (psm == PSM_SDP) && (!require_security_level2_for_outgoing_sdp);
331 }
332 
333 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
334 
335     if (!hci_can_send_acl_packet_now(handle)){
336         log_info("l2cap_send_signaling_packet, cannot send");
337         return BTSTACK_ACL_BUFFERS_FULL;
338     }
339 
340     // log_info("l2cap_send_signaling_packet type %u", cmd);
341     hci_reserve_packet_buffer();
342     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
343     va_list argptr;
344     va_start(argptr, identifier);
345     uint16_t len = l2cap_create_signaling_classic(acl_buffer, handle, cmd, identifier, argptr);
346     va_end(argptr);
347     // log_info("l2cap_send_signaling_packet con %u!", handle);
348     return hci_send_acl_packet_buffer(len);
349 }
350 
351 #ifdef HAVE_BLE
352 int l2cap_send_le_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
353 
354     if (!hci_can_send_acl_packet_now(handle)){
355         log_info("l2cap_send_signaling_packet, cannot send");
356         return BTSTACK_ACL_BUFFERS_FULL;
357     }
358 
359     // log_info("l2cap_send_signaling_packet type %u", cmd);
360     hci_reserve_packet_buffer();
361     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
362     va_list argptr;
363     va_start(argptr, identifier);
364     uint16_t len = l2cap_create_signaling_le(acl_buffer, handle, cmd, identifier, argptr);
365     va_end(argptr);
366     // log_info("l2cap_send_signaling_packet con %u!", handle);
367     return hci_send_acl_packet_buffer(len);
368 }
369 #endif
370 
371 uint8_t *l2cap_get_outgoing_buffer(void){
372     return hci_get_outgoing_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes
373 }
374 
375 int l2cap_reserve_packet_buffer(void){
376     return hci_reserve_packet_buffer();
377 }
378 
379 void l2cap_release_packet_buffer(void){
380     hci_release_packet_buffer();
381 }
382 
383 
384 int l2cap_send_prepared(uint16_t local_cid, uint16_t len){
385 
386     if (!hci_is_packet_buffer_reserved()){
387         log_error("l2cap_send_prepared called without reserving packet first");
388         return BTSTACK_ACL_BUFFERS_FULL;
389     }
390 
391     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
392     if (!channel) {
393         log_error("l2cap_send_prepared no channel for cid 0x%02x", local_cid);
394         return -1;   // TODO: define error
395     }
396 
397     if (channel->packets_granted == 0){
398         log_error("l2cap_send_prepared cid 0x%02x, no credits!", local_cid);
399         return -1;  // TODO: define error
400     }
401 
402     if (!hci_can_send_prepared_acl_packet_now(channel->handle)){
403         log_info("l2cap_send_prepared cid 0x%02x, cannot send", local_cid);
404         return BTSTACK_ACL_BUFFERS_FULL;
405     }
406 
407     --channel->packets_granted;
408 
409     log_debug("l2cap_send_prepared cid 0x%02x, handle %u, 1 credit used, credits left %u;",
410                   local_cid, channel->handle, channel->packets_granted);
411 
412     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
413 
414     int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
415 
416     // 0 - Connection handle : PB=pb : BC=00
417     bt_store_16(acl_buffer, 0, channel->handle | (pb << 12) | (0 << 14));
418     // 2 - ACL length
419     bt_store_16(acl_buffer, 2,  len + 4);
420     // 4 - L2CAP packet length
421     bt_store_16(acl_buffer, 4,  len + 0);
422     // 6 - L2CAP channel DEST
423     bt_store_16(acl_buffer, 6, channel->remote_cid);
424     // send
425     int err = hci_send_acl_packet_buffer(len+8);
426 
427     l2cap_hand_out_credits();
428 
429     return err;
430 }
431 
432 int l2cap_send_prepared_connectionless(uint16_t handle, uint16_t cid, uint16_t len){
433 
434     if (!hci_is_packet_buffer_reserved()){
435         log_error("l2cap_send_prepared_connectionless called without reserving packet first");
436         return BTSTACK_ACL_BUFFERS_FULL;
437     }
438 
439     if (!hci_can_send_prepared_acl_packet_now(handle)){
440         log_info("l2cap_send_prepared_connectionless handle 0x%02x, cid 0x%02x, cannot send", handle, cid);
441         return BTSTACK_ACL_BUFFERS_FULL;
442     }
443 
444     log_debug("l2cap_send_prepared_connectionless handle %u, cid 0x%02x", handle, cid);
445 
446     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
447 
448     int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
449 
450     // 0 - Connection handle : PB=pb : BC=00
451     bt_store_16(acl_buffer, 0, handle | (pb << 12) | (0 << 14));
452     // 2 - ACL length
453     bt_store_16(acl_buffer, 2,  len + 4);
454     // 4 - L2CAP packet length
455     bt_store_16(acl_buffer, 4,  len + 0);
456     // 6 - L2CAP channel DEST
457     bt_store_16(acl_buffer, 6, cid);
458     // send
459     int err = hci_send_acl_packet_buffer(len+8);
460 
461     l2cap_hand_out_credits();
462 
463     return err;
464 }
465 
466 int l2cap_send_internal(uint16_t local_cid, uint8_t *data, uint16_t len){
467 
468     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
469     if (!channel) {
470         log_error("l2cap_send_internal no channel for cid 0x%02x", local_cid);
471         return -1;   // TODO: define error
472     }
473 
474     if (len > channel->remote_mtu){
475         log_error("l2cap_send_internal cid 0x%02x, data length exceeds remote MTU.", local_cid);
476         return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU;
477     }
478 
479     if (!hci_can_send_acl_packet_now(channel->handle)){
480         log_info("l2cap_send_internal cid 0x%02x, cannot send", local_cid);
481         return BTSTACK_ACL_BUFFERS_FULL;
482     }
483 
484     hci_reserve_packet_buffer();
485     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
486 
487     memcpy(&acl_buffer[8], data, len);
488 
489     return l2cap_send_prepared(local_cid, len);
490 }
491 
492 int l2cap_send_connectionless(uint16_t handle, uint16_t cid, uint8_t *data, uint16_t len){
493 
494     if (!hci_can_send_acl_packet_now(handle)){
495         log_info("l2cap_send_internal cid 0x%02x, cannot send", cid);
496         return BTSTACK_ACL_BUFFERS_FULL;
497     }
498 
499     hci_reserve_packet_buffer();
500     uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
501 
502     memcpy(&acl_buffer[8], data, len);
503 
504     return l2cap_send_prepared_connectionless(handle, cid, len);
505 }
506 
507 int l2cap_send_echo_request(uint16_t handle, uint8_t *data, uint16_t len){
508     return l2cap_send_signaling_packet(handle, ECHO_REQUEST, 0x77, len, data);
509 }
510 
511 static inline void channelStateVarSetFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
512     channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var | flag);
513 }
514 
515 static inline void channelStateVarClearFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
516     channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var & ~flag);
517 }
518 
519 
520 
521 // MARK: L2CAP_RUN
522 // process outstanding signaling tasks
523 void l2cap_run(void){
524 
525     // log_info("l2cap_run: entered");
526 
527     // check pending signaling responses
528     while (signaling_responses_pending){
529 
530         hci_con_handle_t handle = signaling_responses[0].handle;
531 
532         if (!hci_can_send_acl_packet_now(handle)) break;
533 
534         uint8_t  sig_id = signaling_responses[0].sig_id;
535         uint16_t infoType = signaling_responses[0].data;    // INFORMATION_REQUEST
536         uint16_t result   = signaling_responses[0].data;    // CONNECTION_REQUEST, COMMAND_REJECT
537         uint8_t  response_code = signaling_responses[0].code;
538 
539         // remove first item before sending (to avoid sending response mutliple times)
540         signaling_responses_pending--;
541         int i;
542         for (i=0; i < signaling_responses_pending; i++){
543             memcpy(&signaling_responses[i], &signaling_responses[i+1], sizeof(l2cap_signaling_response_t));
544         }
545 
546         switch (response_code){
547             case CONNECTION_REQUEST:
548                 l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0);
549                 // also disconnect if result is 0x0003 - security blocked
550                 if (result == 0x0003){
551                     hci_disconnect_security_block(handle);
552                 }
553                 break;
554             case ECHO_REQUEST:
555                 l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL);
556                 break;
557             case INFORMATION_REQUEST:
558                 switch (infoType){
559                     case 1: { // Connectionless MTU
560                         uint16_t connectionless_mtu = hci_max_acl_data_packet_length();
561                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(connectionless_mtu), &connectionless_mtu);
562                         break;
563                     }
564                     case 2: { // Extended Features Supported
565                         // extended features request supported, features: fixed channels, unicast connectionless data reception
566                         uint32_t features = 0x280;
567                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(features), &features);
568                         break;
569                     }
570                     case 3: { // Fixed Channels Supported
571                         uint8_t map[8];
572                         memset(map, 0, 8);
573                         map[0] = 0x01;  // L2CAP Signaling Channel (0x01) + Connectionless reception (0x02)
574                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(map), &map);
575                         break;
576                     }
577                     default:
578                         // all other types are not supported
579                         l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL);
580                         break;
581                 }
582                 break;
583             case COMMAND_REJECT:
584                 l2cap_send_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
585 #ifdef HAVE_BLE
586             case COMMAND_REJECT_LE:
587                 l2cap_send_le_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
588                 break;
589 #endif
590             default:
591                 // should not happen
592                 break;
593         }
594     }
595 
596     uint8_t  config_options[4];
597     linked_list_iterator_t it;
598     linked_list_iterator_init(&it, &l2cap_channels);
599     while (linked_list_iterator_has_next(&it)){
600 
601         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
602         // log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var);
603         switch (channel->state){
604 
605             case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
606             case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT:
607                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
608                 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND) {
609                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND);
610                     l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 1, 0);
611                 }
612                 break;
613 
614             case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
615                 if (!hci_can_send_command_packet_now()) break;
616                 // send connection request - set state first
617                 channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE;
618                 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch
619                 hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1);
620                 break;
621 
622             case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE:
623                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
624                 channel->state = L2CAP_STATE_INVALID;
625                 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, channel->reason, 0);
626                 // discard channel - l2cap_finialize_channel_close without sending l2cap close event
627                 l2cap_stop_rtx(channel);
628                 linked_list_iterator_remove(&it);
629                 btstack_memory_l2cap_channel_free(channel);
630                 break;
631 
632             case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT:
633                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
634                 channel->state = L2CAP_STATE_CONFIG;
635                 channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
636                 l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0);
637                 break;
638 
639             case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST:
640                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
641                 // success, start l2cap handshake
642                 channel->local_sig_id = l2cap_next_sig_id();
643                 channel->state = L2CAP_STATE_WAIT_CONNECT_RSP;
644                 l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid);
645                 l2cap_start_rtx(channel);
646                 break;
647 
648             case L2CAP_STATE_CONFIG:
649                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
650                 if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){
651                     uint16_t flags = 0;
652                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
653                     if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT) {
654                         flags = 1;
655                     } else {
656                         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP);
657                     }
658                     if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID){
659                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_UNKNOWN_OPTIONS, 0, NULL);
660                     } else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU){
661                         config_options[0] = 1; // MTU
662                         config_options[1] = 2; // len param
663                         bt_store_16( (uint8_t*)&config_options, 2, channel->remote_mtu);
664                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 4, &config_options);
665                         channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
666                     } else {
667                         l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 0, NULL);
668                     }
669                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
670                 }
671                 else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){
672                     channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
673                     channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ);
674                     channel->local_sig_id = l2cap_next_sig_id();
675                     config_options[0] = 1; // MTU
676                     config_options[1] = 2; // len param
677                     bt_store_16( (uint8_t*)&config_options, 2, channel->local_mtu);
678                     l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options);
679                     l2cap_start_rtx(channel);
680                 }
681                 if (l2cap_channel_ready_for_open(channel)){
682                     channel->state = L2CAP_STATE_OPEN;
683                     l2cap_emit_channel_opened(channel, 0);  // success
684                     l2cap_emit_credits(channel, 1);
685                 }
686                 break;
687 
688             case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE:
689                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
690                 channel->state = L2CAP_STATE_INVALID;
691                 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid);
692                 // 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 :)
693                 l2cap_finialize_channel_close(channel);  // -- remove from list
694                 break;
695 
696             case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
697                 if (!hci_can_send_acl_packet_now(channel->handle)) break;
698                 channel->local_sig_id = l2cap_next_sig_id();
699                 channel->state = L2CAP_STATE_WAIT_DISCONNECT;
700                 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid);
701                 break;
702             default:
703                 break;
704         }
705     }
706 
707 #ifdef HAVE_BLE
708     // send l2cap con paramter update if necessary
709     hci_connections_get_iterator(&it);
710     while(linked_list_iterator_has_next(&it)){
711         hci_connection_t * connection = (hci_connection_t *) linked_list_iterator_next(&it);
712         if (!hci_can_send_acl_packet_now(connection->con_handle)) continue;
713         switch (connection->le_con_parameter_update_state){
714             case CON_PARAMETER_UPDATE_SEND_REQUEST:
715                 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE;
716                 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_REQUEST, connection->le_con_param_update_identifier,
717                                                connection->le_conn_interval_min, connection->le_conn_interval_max, connection->le_conn_latency, connection->le_supervision_timeout);
718                 break;
719             case CON_PARAMETER_UPDATE_SEND_RESPONSE:
720                 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_CHANGE_HCI_CON_PARAMETERS;
721                 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 0);
722                 break;
723             case CON_PARAMETER_UPDATE_DENY:
724                 connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE;
725                 l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 1);
726                 break;
727             default:
728                 break;
729         }
730     }
731 #endif
732 
733     // log_info("l2cap_run: exit");
734 }
735 
736 uint16_t l2cap_max_mtu(void){
737     return HCI_ACL_PAYLOAD_SIZE - L2CAP_HEADER_SIZE;
738 }
739 
740 uint16_t l2cap_max_le_mtu(void){
741     return l2cap_max_mtu();
742 }
743 
744 static void l2cap_handle_connection_complete(uint16_t handle, l2cap_channel_t * channel){
745     if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) {
746         log_info("l2cap_handle_connection_complete expected state");
747         // success, start l2cap handshake
748         channel->handle = handle;
749         channel->local_cid = l2cap_next_local_cid();
750         // check remote SSP feature first
751         channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES;
752     }
753 }
754 
755 static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){
756     if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return;
757 
758     // we have been waiting for remote supported features, if both support SSP,
759     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));
760     if (hci_ssp_supported_on_both_sides(channel->handle) && !l2cap_security_level_0_allowed_for_PSM(channel->psm)){
761         // request security level 2
762         channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE;
763         gap_request_security_level(channel->handle, LEVEL_2);
764         return;
765     }
766     // fine, go ahead
767     channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
768 }
769 
770 // open outgoing L2CAP channel
771 void l2cap_create_channel_internal(void * connection, btstack_packet_handler_t packet_handler,
772                                    bd_addr_t address, uint16_t psm, uint16_t mtu){
773 
774     log_info("L2CAP_CREATE_CHANNEL_MTU addr %s psm 0x%x mtu %u", bd_addr_to_str(address), psm, mtu);
775 
776     // alloc structure
777     l2cap_channel_t * chan = btstack_memory_l2cap_channel_get();
778     if (!chan) {
779         // emit error event
780         l2cap_channel_t dummy_channel;
781         BD_ADDR_COPY(dummy_channel.address, address);
782         dummy_channel.psm = psm;
783         l2cap_emit_channel_opened(&dummy_channel, BTSTACK_MEMORY_ALLOC_FAILED);
784         return;
785     }
786     // Init memory (make valgrind happy)
787     memset(chan, 0, sizeof(l2cap_channel_t));
788     // limit local mtu to max acl packet length - l2cap header
789     if (mtu > l2cap_max_mtu()) {
790         mtu = l2cap_max_mtu();
791     }
792 
793     // fill in
794     BD_ADDR_COPY(chan->address, address);
795     chan->psm = psm;
796     chan->handle = 0;
797     chan->connection = connection;
798     chan->packet_handler = packet_handler;
799     chan->remote_mtu = L2CAP_MINIMAL_MTU;
800     chan->local_mtu = mtu;
801     chan->packets_granted = 0;
802 
803     // set initial state
804     chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION;
805     chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE;
806     chan->remote_sig_id = L2CAP_SIG_ID_INVALID;
807     chan->local_sig_id = L2CAP_SIG_ID_INVALID;
808     chan->required_security_level = LEVEL_0;
809 
810     // add to connections list
811     linked_list_add(&l2cap_channels, (linked_item_t *) chan);
812 
813     // check if hci connection is already usable
814     hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_CLASSIC);
815     if (conn){
816         log_info("l2cap_create_channel_internal, hci connection already exists");
817         l2cap_handle_connection_complete(conn->con_handle, chan);
818         // check if remote supported fearures are already received
819         if (conn->bonding_flags & BONDING_RECEIVED_REMOTE_FEATURES) {
820             l2cap_handle_remote_supported_features_received(chan);
821         }
822     }
823 
824     l2cap_run();
825 }
826 
827 void l2cap_disconnect_internal(uint16_t local_cid, uint8_t reason){
828     log_info("L2CAP_DISCONNECT local_cid 0x%x reason 0x%x", local_cid, reason);
829     // find channel for local_cid
830     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
831     if (channel) {
832         channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST;
833     }
834     // process
835     l2cap_run();
836 }
837 
838 static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){
839     linked_list_iterator_t it;
840     linked_list_iterator_init(&it, &l2cap_channels);
841     while (linked_list_iterator_has_next(&it)){
842         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
843         if ( BD_ADDR_CMP( channel->address, address) != 0) continue;
844         // channel for this address found
845         switch (channel->state){
846             case L2CAP_STATE_WAIT_CONNECTION_COMPLETE:
847             case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
848                 // failure, forward error code
849                 l2cap_emit_channel_opened(channel, status);
850                 // discard channel
851                 l2cap_stop_rtx(channel);
852                 linked_list_iterator_remove(&it);
853                 btstack_memory_l2cap_channel_free(channel);
854                 break;
855             default:
856                 break;
857         }
858     }
859 }
860 
861 static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){
862     linked_list_iterator_t it;
863     linked_list_iterator_init(&it, &l2cap_channels);
864     while (linked_list_iterator_has_next(&it)){
865         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
866         if ( ! BD_ADDR_CMP( channel->address, address) ){
867             l2cap_handle_connection_complete(handle, channel);
868         }
869     }
870     // process
871     l2cap_run();
872 }
873 
874 void l2cap_event_handler(uint8_t *packet, uint16_t size){
875 
876     bd_addr_t address;
877     hci_con_handle_t handle;
878     linked_list_iterator_t it;
879     int hci_con_used;
880 
881     switch(packet[0]){
882 
883         // handle connection complete events
884         case HCI_EVENT_CONNECTION_COMPLETE:
885             bt_flip_addr(address, &packet[5]);
886             if (packet[2] == 0){
887                 handle = READ_BT_16(packet, 3);
888                 l2cap_handle_connection_success_for_addr(address, handle);
889             } else {
890                 l2cap_handle_connection_failed_for_addr(address, packet[2]);
891             }
892             break;
893 
894         // handle successful create connection cancel command
895         case HCI_EVENT_COMMAND_COMPLETE:
896             if ( COMMAND_COMPLETE_EVENT(packet, hci_create_connection_cancel) ) {
897                 if (packet[5] == 0){
898                     bt_flip_addr(address, &packet[6]);
899                     // CONNECTION TERMINATED BY LOCAL HOST (0X16)
900                     l2cap_handle_connection_failed_for_addr(address, 0x16);
901                 }
902             }
903             l2cap_run();    // try sending signaling packets first
904             break;
905 
906         case HCI_EVENT_COMMAND_STATUS:
907             l2cap_run();    // try sending signaling packets first
908             break;
909 
910         // handle disconnection complete events
911         case HCI_EVENT_DISCONNECTION_COMPLETE:
912             // send l2cap disconnect events for all channels on this handle and free them
913             handle = READ_BT_16(packet, 3);
914             linked_list_iterator_init(&it, &l2cap_channels);
915             while (linked_list_iterator_has_next(&it)){
916                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
917                 if (channel->handle != handle) continue;
918                 l2cap_emit_channel_closed(channel);
919                 l2cap_stop_rtx(channel);
920                 linked_list_iterator_remove(&it);
921                 btstack_memory_l2cap_channel_free(channel);
922             }
923             break;
924 
925         case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS:
926             l2cap_run();    // try sending signaling packets first
927             l2cap_hand_out_credits();
928             break;
929 
930         // HCI Connection Timeouts
931         case L2CAP_EVENT_TIMEOUT_CHECK:
932             handle = READ_BT_16(packet, 2);
933             if (hci_authentication_active_for_handle(handle)) break;
934             hci_con_used = 0;
935             linked_list_iterator_init(&it, &l2cap_channels);
936             while (linked_list_iterator_has_next(&it)){
937                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
938                 if (channel->handle != handle) continue;
939                 hci_con_used = 1;
940                 break;
941             }
942             if (hci_con_used) break;
943             if (!hci_can_send_command_packet_now()) break;
944             hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection
945             break;
946 
947         case DAEMON_EVENT_HCI_PACKET_SENT:
948             linked_list_iterator_init(&it, &l2cap_channels);
949             while (linked_list_iterator_has_next(&it)){
950                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
951                 if (!channel->packet_handler) continue;
952                 (* (channel->packet_handler))(HCI_EVENT_PACKET, channel->local_cid, packet, size);
953             }
954             if (attribute_protocol_packet_handler) {
955                 (*attribute_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
956             }
957             if (security_protocol_packet_handler) {
958                 (*security_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
959             }
960             if (connectionless_channel_packet_handler) {
961                 (*connectionless_channel_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
962             }
963             break;
964 
965         case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE:
966             handle = READ_BT_16(packet, 3);
967             linked_list_iterator_init(&it, &l2cap_channels);
968             while (linked_list_iterator_has_next(&it)){
969                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
970                 if (channel->handle != handle) continue;
971                 l2cap_handle_remote_supported_features_received(channel);
972                 break;
973             }
974             break;
975 
976         case GAP_SECURITY_LEVEL:
977             handle = READ_BT_16(packet, 2);
978             log_info("l2cap - security level update");
979             linked_list_iterator_init(&it, &l2cap_channels);
980             while (linked_list_iterator_has_next(&it)){
981                 l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
982                 if (channel->handle != handle) continue;
983 
984                 log_info("l2cap - state %u", channel->state);
985 
986                 gap_security_level_t actual_level = (gap_security_level_t) packet[4];
987                 gap_security_level_t required_level = channel->required_security_level;
988 
989                 switch (channel->state){
990                     case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
991                         if (actual_level >= required_level){
992                             channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT;
993                             l2cap_emit_connection_request(channel);
994                         } else {
995                             channel->reason = 0x0003; // security block
996                             channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
997                         }
998                         break;
999 
1000                     case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE:
1001                         if (actual_level >= required_level){
1002                             channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
1003                         } else {
1004                             // disconnnect, authentication not good enough
1005                             hci_disconnect_security_block(handle);
1006                         }
1007                         break;
1008 
1009                     default:
1010                         break;
1011                 }
1012             }
1013             break;
1014 
1015         default:
1016             break;
1017     }
1018 
1019     // pass on: main packet handler, att and sm packet handlers
1020     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, packet, size);
1021     if (attribute_protocol_packet_handler){
1022         (*attribute_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
1023     }
1024     if (security_protocol_packet_handler) {
1025         (*security_protocol_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
1026     }
1027     if (connectionless_channel_packet_handler) {
1028         (*connectionless_channel_packet_handler)(HCI_EVENT_PACKET, 0, packet, size);
1029     }
1030 
1031     l2cap_run();
1032 }
1033 
1034 static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){
1035     channel->remote_sig_id = identifier;
1036     channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE;
1037     l2cap_run();
1038 }
1039 
1040 static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){
1041     // Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused."
1042     if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) {
1043         signaling_responses[signaling_responses_pending].handle = handle;
1044         signaling_responses[signaling_responses_pending].code = code;
1045         signaling_responses[signaling_responses_pending].sig_id = sig_id;
1046         signaling_responses[signaling_responses_pending].data = data;
1047         signaling_responses_pending++;
1048         l2cap_run();
1049     }
1050 }
1051 
1052 static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){
1053 
1054     // log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid);
1055     l2cap_service_t *service = l2cap_get_service(psm);
1056     if (!service) {
1057         // 0x0002 PSM not supported
1058         l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002);
1059         return;
1060     }
1061 
1062     hci_connection_t * hci_connection = hci_connection_for_handle( handle );
1063     if (!hci_connection) {
1064         //
1065         log_error("no hci_connection for handle %u", handle);
1066         return;
1067     }
1068 
1069     // alloc structure
1070     // log_info("l2cap_handle_connection_request register channel");
1071     l2cap_channel_t * channel = btstack_memory_l2cap_channel_get();
1072     if (!channel){
1073         // 0x0004 No resources available
1074         l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004);
1075         return;
1076     }
1077     // Init memory (make valgrind happy)
1078     memset(channel, 0, sizeof(l2cap_channel_t));
1079     // fill in
1080     BD_ADDR_COPY(channel->address, hci_connection->address);
1081     channel->psm = psm;
1082     channel->handle = handle;
1083     channel->connection = service->connection;
1084     channel->packet_handler = service->packet_handler;
1085     channel->local_cid  = l2cap_next_local_cid();
1086     channel->remote_cid = source_cid;
1087     channel->local_mtu  = service->mtu;
1088     channel->remote_mtu = L2CAP_DEFAULT_MTU;
1089     channel->packets_granted = 0;
1090     channel->remote_sig_id = sig_id;
1091     channel->required_security_level = service->required_security_level;
1092 
1093     // limit local mtu to max acl packet length - l2cap header
1094     if (channel->local_mtu > l2cap_max_mtu()) {
1095         channel->local_mtu = l2cap_max_mtu();
1096     }
1097 
1098     // set initial state
1099     channel->state =     L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE;
1100     channel->state_var = L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND;
1101 
1102     // add to connections list
1103     linked_list_add(&l2cap_channels, (linked_item_t *) channel);
1104 
1105     // assert security requirements
1106     gap_request_security_level(handle, channel->required_security_level);
1107 }
1108 
1109 void l2cap_accept_connection_internal(uint16_t local_cid){
1110     log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid);
1111     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
1112     if (!channel) {
1113         log_error("l2cap_accept_connection_internal called but local_cid 0x%x not found", local_cid);
1114         return;
1115     }
1116 
1117     channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT;
1118 
1119     // process
1120     l2cap_run();
1121 }
1122 
1123 void l2cap_decline_connection_internal(uint16_t local_cid, uint8_t reason){
1124     log_info("L2CAP_DECLINE_CONNECTION local_cid 0x%x, reason %x", local_cid, reason);
1125     l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid);
1126     if (!channel) {
1127         log_error( "l2cap_decline_connection_internal called but local_cid 0x%x not found", local_cid);
1128         return;
1129     }
1130     channel->state  = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
1131     channel->reason = reason;
1132     l2cap_run();
1133 }
1134 
1135 void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){
1136 
1137     channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1138 
1139     uint16_t flags = READ_BT_16(command, 6);
1140     if (flags & 1) {
1141         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
1142     }
1143 
1144     // accept the other's configuration options
1145     uint16_t end_pos = 4 + READ_BT_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
1146     uint16_t pos     = 8;
1147     while (pos < end_pos){
1148         uint8_t option_hint = command[pos] >> 7;
1149         uint8_t option_type = command[pos] & 0x7f;
1150         log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type);
1151         pos++;
1152         uint8_t length = command[pos++];
1153         // MTU { type(8): 1, len(8):2, MTU(16) }
1154         if (option_type == 1 && length == 2){
1155             channel->remote_mtu = READ_BT_16(command, pos);
1156             // log_info("l2cap cid 0x%02x, remote mtu %u", channel->local_cid, channel->remote_mtu);
1157             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
1158         }
1159         // Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)}
1160         if (option_type == 2 && length == 2){
1161             channel->flush_timeout = READ_BT_16(command, pos);
1162         }
1163         // check for unknown options
1164         if (option_hint == 0 && (option_type == 0 || option_type >= 0x07)){
1165             log_info("l2cap cid %u, unknown options", channel->local_cid);
1166             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID);
1167         }
1168         pos += length;
1169     }
1170 }
1171 
1172 static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){
1173     // log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var);
1174     if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0;
1175     if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0;
1176     // addition check that fixes re-entrance issue causing l2cap event channel opened twice
1177     if (channel->state == L2CAP_STATE_OPEN) return 0;
1178     return 1;
1179 }
1180 
1181 
1182 void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){
1183 
1184     uint8_t  code       = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
1185     uint8_t  identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1186     uint16_t result = 0;
1187 
1188     log_info("L2CAP signaling handler code %u, state %u", code, channel->state);
1189 
1190     // handle DISCONNECT REQUESTS seperately
1191     if (code == DISCONNECTION_REQUEST){
1192         switch (channel->state){
1193             case L2CAP_STATE_CONFIG:
1194             case L2CAP_STATE_OPEN:
1195             case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
1196             case L2CAP_STATE_WAIT_DISCONNECT:
1197                 l2cap_handle_disconnect_request(channel, identifier);
1198                 break;
1199 
1200             default:
1201                 // ignore in other states
1202                 break;
1203         }
1204         return;
1205     }
1206 
1207     // @STATEMACHINE(l2cap)
1208     switch (channel->state) {
1209 
1210         case L2CAP_STATE_WAIT_CONNECT_RSP:
1211             switch (code){
1212                 case CONNECTION_RESPONSE:
1213                     l2cap_stop_rtx(channel);
1214                     result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
1215                     switch (result) {
1216                         case 0:
1217                             // successful connection
1218                             channel->remote_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1219                             channel->state = L2CAP_STATE_CONFIG;
1220                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
1221                             break;
1222                         case 1:
1223                             // connection pending. get some coffee, but start the ERTX
1224                             l2cap_start_ertx(channel);
1225                             break;
1226                         default:
1227                             // channel closed
1228                             channel->state = L2CAP_STATE_CLOSED;
1229                             // map l2cap connection response result to BTstack status enumeration
1230                             l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result);
1231 
1232                             // drop link key if security block
1233                             if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){
1234                                 hci_drop_link_key_for_bd_addr(channel->address);
1235                             }
1236 
1237                             // discard channel
1238                             linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
1239                             btstack_memory_l2cap_channel_free(channel);
1240                             break;
1241                     }
1242                     break;
1243 
1244                 default:
1245                     //@TODO: implement other signaling packets
1246                     break;
1247             }
1248             break;
1249 
1250         case L2CAP_STATE_CONFIG:
1251             result = READ_BT_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
1252             switch (code) {
1253                 case CONFIGURE_REQUEST:
1254                     channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
1255                     l2cap_signaling_handle_configure_request(channel, command);
1256                     if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){
1257                         // only done if continuation not set
1258                         channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ);
1259                     }
1260                     break;
1261                 case CONFIGURE_RESPONSE:
1262                     l2cap_stop_rtx(channel);
1263                     switch (result){
1264                         case 0: // success
1265                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP);
1266                             break;
1267                         case 4: // pending
1268                             l2cap_start_ertx(channel);
1269                             break;
1270                         default:
1271                             // retry on negative result
1272                             channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
1273                             break;
1274                     }
1275                     break;
1276                 default:
1277                     break;
1278             }
1279             if (l2cap_channel_ready_for_open(channel)){
1280                 // for open:
1281                 channel->state = L2CAP_STATE_OPEN;
1282                 l2cap_emit_channel_opened(channel, 0);
1283                 l2cap_emit_credits(channel, 1);
1284             }
1285             break;
1286 
1287         case L2CAP_STATE_WAIT_DISCONNECT:
1288             switch (code) {
1289                 case DISCONNECTION_RESPONSE:
1290                     l2cap_finialize_channel_close(channel);
1291                     break;
1292                 default:
1293                     //@TODO: implement other signaling packets
1294                     break;
1295             }
1296             break;
1297 
1298         case L2CAP_STATE_CLOSED:
1299             // @TODO handle incoming requests
1300             break;
1301 
1302         case L2CAP_STATE_OPEN:
1303             //@TODO: implement other signaling packets, e.g. re-configure
1304             break;
1305         default:
1306             break;
1307     }
1308     // log_info("new state %u", channel->state);
1309 }
1310 
1311 
1312 void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){
1313 
1314     // get code, signalind identifier and command len
1315     uint8_t code   = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
1316     uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
1317 
1318     // not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST
1319     if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){
1320         l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, L2CAP_REJ_CMD_UNKNOWN);
1321         return;
1322     }
1323 
1324     // general commands without an assigned channel
1325     switch(code) {
1326 
1327         case CONNECTION_REQUEST: {
1328             uint16_t psm =        READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1329             uint16_t source_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2);
1330             l2cap_handle_connection_request(handle, sig_id, psm, source_cid);
1331             return;
1332         }
1333 
1334         case ECHO_REQUEST:
1335             l2cap_register_signaling_response(handle, code, sig_id, 0);
1336             return;
1337 
1338         case INFORMATION_REQUEST: {
1339             uint16_t infoType = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1340             l2cap_register_signaling_response(handle, code, sig_id, infoType);
1341             return;
1342         }
1343 
1344         default:
1345             break;
1346     }
1347 
1348 
1349     // Get potential destination CID
1350     uint16_t dest_cid = READ_BT_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
1351 
1352     // Find channel for this sig_id and connection handle
1353     linked_list_iterator_t it;
1354     linked_list_iterator_init(&it, &l2cap_channels);
1355     while (linked_list_iterator_has_next(&it)){
1356         l2cap_channel_t * channel = (l2cap_channel_t *) linked_list_iterator_next(&it);
1357         if (channel->handle != handle) continue;
1358         if (code & 1) {
1359             // match odd commands (responses) by previous signaling identifier
1360             if (channel->local_sig_id == sig_id) {
1361                 l2cap_signaling_handler_channel(channel, command);
1362                 break;
1363             }
1364         } else {
1365             // match even commands (requests) by local channel id
1366             if (channel->local_cid == dest_cid) {
1367                 l2cap_signaling_handler_channel(channel, command);
1368                 break;
1369             }
1370         }
1371     }
1372 }
1373 
1374 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){
1375 
1376     // Get Channel ID
1377     uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet);
1378     hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet);
1379 
1380     switch (channel_id) {
1381 
1382         case L2CAP_CID_SIGNALING: {
1383 
1384             uint16_t command_offset = 8;
1385             while (command_offset < size) {
1386 
1387                 // handle signaling commands
1388                 l2cap_signaling_handler_dispatch(handle, &packet[command_offset]);
1389 
1390                 // increment command_offset
1391                 command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + READ_BT_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
1392             }
1393             break;
1394         }
1395 
1396         case L2CAP_CID_ATTRIBUTE_PROTOCOL:
1397             if (attribute_protocol_packet_handler) {
1398                 (*attribute_protocol_packet_handler)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1399             }
1400             break;
1401 
1402         case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
1403             if (security_protocol_packet_handler) {
1404                 (*security_protocol_packet_handler)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1405             }
1406             break;
1407 
1408         case L2CAP_CID_CONNECTIONLESS_CHANNEL:
1409             if (connectionless_channel_packet_handler) {
1410                 (*connectionless_channel_packet_handler)(UCD_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1411             }
1412             break;
1413 
1414         case L2CAP_CID_SIGNALING_LE: {
1415             switch (packet[8]){
1416                 case CONNECTION_PARAMETER_UPDATE_RESPONSE: {
1417                     uint16_t result = READ_BT_16(packet, 12);
1418                     l2cap_emit_connection_parameter_update_response(handle, result);
1419                     break;
1420                 }
1421                 case CONNECTION_PARAMETER_UPDATE_REQUEST: {
1422                     uint8_t event[10];
1423                     event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST;
1424                     event[1] = 8;
1425                     memcpy(&event[2], &packet[12], 8);
1426 
1427                     hci_connection_t * connection = hci_connection_for_handle(handle);
1428                     if (connection){
1429                         if (connection->role != HCI_ROLE_MASTER){
1430                             // reject command without notifying upper layer when not in master role
1431                             uint8_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1];
1432                             l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, L2CAP_REJ_CMD_UNKNOWN);
1433                             break;
1434                         }
1435                         int update_parameter = 1;
1436                         le_connection_parameter_range_t existing_range = gap_le_get_connection_parameter_range();
1437                         uint16_t le_conn_interval_min = READ_BT_16(packet,12);
1438                         uint16_t le_conn_interval_max = READ_BT_16(packet,14);
1439                         uint16_t le_conn_latency = READ_BT_16(packet,16);
1440                         uint16_t le_supervision_timeout = READ_BT_16(packet,18);
1441 
1442                         if (le_conn_interval_min < existing_range.le_conn_interval_min) update_parameter = 0;
1443                         if (le_conn_interval_max > existing_range.le_conn_interval_max) update_parameter = 0;
1444 
1445                         if (le_conn_latency < existing_range.le_conn_latency_min) update_parameter = 0;
1446                         if (le_conn_latency > existing_range.le_conn_latency_max) update_parameter = 0;
1447 
1448                         if (le_supervision_timeout < existing_range.le_supervision_timeout_min) update_parameter = 0;
1449                         if (le_supervision_timeout > existing_range.le_supervision_timeout_max) update_parameter = 0;
1450 
1451                         if (update_parameter){
1452                             connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE;
1453                             connection->le_conn_interval_min = le_conn_interval_min;
1454                             connection->le_conn_interval_max = le_conn_interval_max;
1455                             connection->le_conn_latency = le_conn_latency;
1456                             connection->le_supervision_timeout = le_supervision_timeout;
1457                         } else {
1458                             connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY;
1459                         }
1460                         connection->le_con_param_update_identifier = packet[COMPLETE_L2CAP_HEADER + 1];
1461                     }
1462 
1463                     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1464                     (*packet_handler)(NULL, HCI_EVENT_PACKET, 0, event, sizeof(event));
1465 
1466                     break;
1467                 }
1468                 default: {
1469                     uint8_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1];
1470                     l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, L2CAP_REJ_CMD_UNKNOWN);
1471                     break;
1472                 }
1473             }
1474             break;
1475         }
1476 
1477         default: {
1478             // Find channel for this channel_id and connection handle
1479             l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id);
1480             if (channel) {
1481                 l2cap_dispatch(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
1482             }
1483             break;
1484         }
1485     }
1486 }
1487 
1488 static void l2cap_packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
1489     switch (packet_type) {
1490         case HCI_EVENT_PACKET:
1491             l2cap_event_handler(packet, size);
1492             break;
1493         case HCI_ACL_DATA_PACKET:
1494             l2cap_acl_handler(packet, size);
1495             break;
1496         default:
1497             break;
1498     }
1499     l2cap_run();
1500 }
1501 
1502 // finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE
1503 void l2cap_finialize_channel_close(l2cap_channel_t *channel){
1504     channel->state = L2CAP_STATE_CLOSED;
1505     l2cap_emit_channel_closed(channel);
1506     // discard channel
1507     l2cap_stop_rtx(channel);
1508     linked_list_remove(&l2cap_channels, (linked_item_t *) channel);
1509     btstack_memory_l2cap_channel_free(channel);
1510 }
1511 
1512 static l2cap_service_t * l2cap_get_service_internal(linked_list_t * services, uint16_t psm){
1513     linked_list_iterator_t it;
1514     linked_list_iterator_init(&it, services);
1515     while (linked_list_iterator_has_next(&it)){
1516         l2cap_service_t * service = (l2cap_service_t *) linked_list_iterator_next(&it);
1517         if ( service->psm == psm){
1518             return service;
1519         };
1520     }
1521     return NULL;
1522 }
1523 
1524 static inline l2cap_service_t * l2cap_get_service(uint16_t psm){
1525     return l2cap_get_service_internal(&l2cap_services, psm);
1526 }
1527 
1528 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){
1529 
1530     log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u connection %p", psm, mtu, connection);
1531 
1532     // check for alread registered psm
1533     // TODO: emit error event
1534     l2cap_service_t *service = l2cap_get_service(psm);
1535     if (service) {
1536         log_error("l2cap_register_service_internal: PSM %u already registered", psm);
1537         l2cap_emit_service_registered(connection, L2CAP_SERVICE_ALREADY_REGISTERED, psm);
1538         return;
1539     }
1540 
1541     // alloc structure
1542     // TODO: emit error event
1543     service = btstack_memory_l2cap_service_get();
1544     if (!service) {
1545         log_error("l2cap_register_service_internal: no memory for l2cap_service_t");
1546         l2cap_emit_service_registered(connection, BTSTACK_MEMORY_ALLOC_FAILED, psm);
1547         return;
1548     }
1549 
1550     // fill in
1551     service->psm = psm;
1552     service->mtu = mtu;
1553     service->connection = connection;
1554     service->packet_handler = packet_handler;
1555     service->required_security_level = security_level;
1556 
1557     // add to services list
1558     linked_list_add(&l2cap_services, (linked_item_t *) service);
1559 
1560     // enable page scan
1561     hci_connectable_control(1);
1562 
1563     // done
1564     l2cap_emit_service_registered(connection, 0, psm);
1565 }
1566 
1567 void l2cap_unregister_service_internal(void *connection, uint16_t psm){
1568 
1569     log_info("L2CAP_UNREGISTER_SERVICE psm 0x%x", psm);
1570 
1571     l2cap_service_t *service = l2cap_get_service(psm);
1572     if (!service) return;
1573     linked_list_remove(&l2cap_services, (linked_item_t *) service);
1574     btstack_memory_l2cap_service_free(service);
1575 
1576     // disable page scan when no services registered
1577     if (!linked_list_empty(&l2cap_services)) return;
1578     hci_connectable_control(0);
1579 }
1580 
1581 // Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol
1582 void l2cap_register_fixed_channel(btstack_packet_handler_t packet_handler, uint16_t channel_id) {
1583     switch(channel_id){
1584         case L2CAP_CID_ATTRIBUTE_PROTOCOL:
1585             attribute_protocol_packet_handler = packet_handler;
1586             break;
1587         case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
1588             security_protocol_packet_handler = packet_handler;
1589             break;
1590         case L2CAP_CID_CONNECTIONLESS_CHANNEL:
1591             connectionless_channel_packet_handler = packet_handler;
1592             break;
1593     }
1594 }
1595 
1596 #ifdef HAVE_BLE
1597 
1598 static inline l2cap_service_t * l2cap_le_get_service(uint16_t psm){
1599     return l2cap_get_service_internal(&l2cap_le_services, psm);
1600 }
1601 
1602 /**
1603  * @brief Regster L2CAP LE Credit Based Flow Control Mode service
1604  * @param
1605  */
1606 void l2cap_le_register_service_internal(void * connection, btstack_packet_handler_t packet_handler, uint16_t psm,
1607     uint16_t mtu, uint16_t mps, uint16_t initial_credits, gap_security_level_t security_level){
1608 
1609     log_info("L2CAP_LE_REGISTER_SERVICE psm 0x%x mtu %u connection %p", psm, mtu, connection);
1610 
1611     // check for alread registered psm
1612     // TODO: emit error event
1613     l2cap_service_t *service = l2cap_le_get_service(psm);
1614     if (service) {
1615         log_error("l2cap_le_register_service_internal: PSM %u already registered", psm);
1616         l2cap_emit_service_registered(connection, L2CAP_SERVICE_ALREADY_REGISTERED, psm);
1617         return;
1618     }
1619 
1620     // alloc structure
1621     // TODO: emit error event
1622     service = btstack_memory_l2cap_service_get();
1623     if (!service) {
1624         log_error("l2cap_register_service_internal: no memory for l2cap_service_t");
1625         l2cap_emit_service_registered(connection, BTSTACK_MEMORY_ALLOC_FAILED, psm);
1626         return;
1627     }
1628 
1629     // fill in
1630     service->psm = psm;
1631     service->mtu = mtu;
1632     service->mps = mps;
1633     service->connection = connection;
1634     service->packet_handler = packet_handler;
1635     service->required_security_level = security_level;
1636 
1637     // add to services list
1638     linked_list_add(&l2cap_le_services, (linked_item_t *) service);
1639 
1640     // done
1641     l2cap_emit_service_registered(connection, 0, psm);
1642 }
1643 
1644 void l2cap_le_unregister_service_internal(void * connection, uint16_t psm) {
1645 
1646     log_info("L2CAP_LE_UNREGISTER_SERVICE psm 0x%x", psm);
1647 
1648     l2cap_service_t *service = l2cap_le_get_service(psm);
1649     if (!service) return;
1650     linked_list_remove(&l2cap_le_services, (linked_item_t *) service);
1651     btstack_memory_l2cap_service_free(service);
1652 }
1653 #endif
1654