xref: /btstack/src/ble/sm.c (revision f03cd3a129c3be1a5bf19b016a47c61c8c778dad)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define __BTSTACK_FILE__ "sm.c"
39 
40 #include <stdio.h>
41 #include <string.h>
42 #include <inttypes.h>
43 
44 #include "ble/le_device_db.h"
45 #include "ble/core.h"
46 #include "ble/sm.h"
47 #include "bluetooth_company_id.h"
48 #include "btstack_debug.h"
49 #include "btstack_event.h"
50 #include "btstack_linked_list.h"
51 #include "btstack_memory.h"
52 #include "gap.h"
53 #include "hci.h"
54 #include "hci_dump.h"
55 #include "l2cap.h"
56 
57 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL)
58 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h."
59 #endif
60 
61 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL)
62 #define IS_RESPONDER(role) (role)
63 #else
64 #ifdef ENABLE_LE_CENTRAL
65 // only central - never responder (avoid 'unused variable' warnings)
66 #define IS_RESPONDER(role) (0 && role)
67 #else
68 // only peripheral - always responder (avoid 'unused variable' warnings)
69 #define IS_RESPONDER(role) (1 || role)
70 #endif
71 #endif
72 
73 #ifdef ENABLE_LE_SECURE_CONNECTIONS
74 // assert SM Public Key can be sent/received
75 #if HCI_ACL_PAYLOAD_SIZE < 69
76 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS"
77 #endif
78 
79 // Software ECDH implementation provided by micro-ecc
80 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
81 #include "uECC.h"
82 #endif
83 #endif
84 
85 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS)
86 #define ENABLE_CMAC_ENGINE
87 #endif
88 
89 //
90 // SM internal types and globals
91 //
92 
93 typedef enum {
94     DKG_W4_WORKING,
95     DKG_CALC_IRK,
96     DKG_W4_IRK,
97     DKG_CALC_DHK,
98     DKG_W4_DHK,
99     DKG_READY
100 } derived_key_generation_t;
101 
102 typedef enum {
103     RAU_W4_WORKING,
104     RAU_IDLE,
105     RAU_GET_RANDOM,
106     RAU_W4_RANDOM,
107     RAU_GET_ENC,
108     RAU_W4_ENC,
109     RAU_SET_ADDRESS,
110 } random_address_update_t;
111 
112 typedef enum {
113     CMAC_IDLE,
114     CMAC_CALC_SUBKEYS,
115     CMAC_W4_SUBKEYS,
116     CMAC_CALC_MI,
117     CMAC_W4_MI,
118     CMAC_CALC_MLAST,
119     CMAC_W4_MLAST
120 } cmac_state_t;
121 
122 typedef enum {
123     JUST_WORKS,
124     PK_RESP_INPUT,  // Initiator displays PK, responder inputs PK
125     PK_INIT_INPUT,  // Responder displays PK, initiator inputs PK
126     OK_BOTH_INPUT,  // Only input on both, both input PK
127     NK_BOTH_INPUT,  // Only numerical compparison (yes/no) on on both sides
128     OOB             // OOB available on both sides
129 } stk_generation_method_t;
130 
131 typedef enum {
132     SM_USER_RESPONSE_IDLE,
133     SM_USER_RESPONSE_PENDING,
134     SM_USER_RESPONSE_CONFIRM,
135     SM_USER_RESPONSE_PASSKEY,
136     SM_USER_RESPONSE_DECLINE
137 } sm_user_response_t;
138 
139 typedef enum {
140     SM_AES128_IDLE,
141     SM_AES128_ACTIVE
142 } sm_aes128_state_t;
143 
144 typedef enum {
145     ADDRESS_RESOLUTION_IDLE,
146     ADDRESS_RESOLUTION_GENERAL,
147     ADDRESS_RESOLUTION_FOR_CONNECTION,
148 } address_resolution_mode_t;
149 
150 typedef enum {
151     ADDRESS_RESOLUTION_SUCEEDED,
152     ADDRESS_RESOLUTION_FAILED,
153 } address_resolution_event_t;
154 
155 typedef enum {
156     EC_KEY_GENERATION_IDLE,
157     EC_KEY_GENERATION_ACTIVE,
158     EC_KEY_GENERATION_W4_KEY,
159     EC_KEY_GENERATION_DONE,
160 } ec_key_generation_state_t;
161 
162 typedef enum {
163     SM_STATE_VAR_DHKEY_NEEDED = 1 << 0,
164     SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1,
165     SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2,
166 } sm_state_var_t;
167 
168 //
169 // GLOBAL DATA
170 //
171 
172 static uint8_t test_use_fixed_local_csrk;
173 
174 // configuration
175 static uint8_t sm_accepted_stk_generation_methods;
176 static uint8_t sm_max_encryption_key_size;
177 static uint8_t sm_min_encryption_key_size;
178 static uint8_t sm_auth_req = 0;
179 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT;
180 static uint8_t sm_slave_request_security;
181 #ifdef ENABLE_LE_SECURE_CONNECTIONS
182 static uint8_t sm_have_ec_keypair;
183 #endif
184 
185 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values
186 static sm_key_t sm_persistent_er;
187 static sm_key_t sm_persistent_ir;
188 
189 // derived from sm_persistent_ir
190 static sm_key_t sm_persistent_dhk;
191 static sm_key_t sm_persistent_irk;
192 static uint8_t  sm_persistent_irk_ready = 0;    // used for testing
193 static derived_key_generation_t dkg_state;
194 
195 // derived from sm_persistent_er
196 // ..
197 
198 // random address update
199 static random_address_update_t rau_state;
200 static bd_addr_t sm_random_address;
201 
202 // CMAC Calculation: General
203 #ifdef ENABLE_CMAC_ENGINE
204 static cmac_state_t sm_cmac_state;
205 static uint16_t     sm_cmac_message_len;
206 static sm_key_t     sm_cmac_k;
207 static sm_key_t     sm_cmac_x;
208 static sm_key_t     sm_cmac_m_last;
209 static uint8_t      sm_cmac_block_current;
210 static uint8_t      sm_cmac_block_count;
211 static uint8_t      (*sm_cmac_get_byte)(uint16_t offset);
212 static void         (*sm_cmac_done_handler)(uint8_t * hash);
213 #endif
214 
215 // CMAC for ATT Signed Writes
216 #ifdef ENABLE_LE_SIGNED_WRITE
217 static uint8_t      sm_cmac_header[3];
218 static const uint8_t * sm_cmac_message;
219 static uint8_t      sm_cmac_sign_counter[4];
220 #endif
221 
222 // CMAC for Secure Connection functions
223 #ifdef ENABLE_LE_SECURE_CONNECTIONS
224 static sm_connection_t * sm_cmac_connection;
225 static uint8_t           sm_cmac_sc_buffer[80];
226 #endif
227 
228 // resolvable private address lookup / CSRK calculation
229 static int       sm_address_resolution_test;
230 static int       sm_address_resolution_ah_calculation_active;
231 static uint8_t   sm_address_resolution_addr_type;
232 static bd_addr_t sm_address_resolution_address;
233 static void *    sm_address_resolution_context;
234 static address_resolution_mode_t sm_address_resolution_mode;
235 static btstack_linked_list_t sm_address_resolution_general_queue;
236 
237 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context
238 static sm_aes128_state_t  sm_aes128_state;
239 static void *             sm_aes128_context;
240 
241 // use aes128 provided by MCU - not needed usually
242 #ifdef HAVE_AES128
243 static uint8_t                aes128_result_flipped[16];
244 static btstack_timer_source_t aes128_timer;
245 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result);
246 #endif
247 
248 // random engine. store context (ususally sm_connection_t)
249 static void * sm_random_context;
250 
251 // to receive hci events
252 static btstack_packet_callback_registration_t hci_event_callback_registration;
253 
254 /* to dispatch sm event */
255 static btstack_linked_list_t sm_event_handlers;
256 
257 // LE Secure Connections
258 #ifdef ENABLE_LE_SECURE_CONNECTIONS
259 static ec_key_generation_state_t ec_key_generation_state;
260 static uint8_t ec_d[32];
261 static uint8_t ec_q[64];
262 #endif
263 
264 //
265 // Volume 3, Part H, Chapter 24
266 // "Security shall be initiated by the Security Manager in the device in the master role.
267 // The device in the slave role shall be the responding device."
268 // -> master := initiator, slave := responder
269 //
270 
271 // data needed for security setup
272 typedef struct sm_setup_context {
273 
274     btstack_timer_source_t sm_timeout;
275 
276     // used in all phases
277     uint8_t   sm_pairing_failed_reason;
278 
279     // user response, (Phase 1 and/or 2)
280     uint8_t   sm_user_response;
281     uint8_t   sm_keypress_notification;
282 
283     // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3
284     int       sm_key_distribution_send_set;
285     int       sm_key_distribution_received_set;
286 
287     // Phase 2 (Pairing over SMP)
288     stk_generation_method_t sm_stk_generation_method;
289     sm_key_t  sm_tk;
290     uint8_t   sm_use_secure_connections;
291 
292     sm_key_t  sm_c1_t3_value;   // c1 calculation
293     sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1
294     sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1
295     sm_key_t  sm_local_random;
296     sm_key_t  sm_local_confirm;
297     sm_key_t  sm_peer_random;
298     sm_key_t  sm_peer_confirm;
299     uint8_t   sm_m_addr_type;   // address and type can be removed
300     uint8_t   sm_s_addr_type;   //  ''
301     bd_addr_t sm_m_address;     //  ''
302     bd_addr_t sm_s_address;     //  ''
303     sm_key_t  sm_ltk;
304 
305     uint8_t   sm_state_vars;
306 #ifdef ENABLE_LE_SECURE_CONNECTIONS
307     uint8_t   sm_peer_q[64];    // also stores random for EC key generation during init
308     sm_key_t  sm_peer_nonce;    // might be combined with sm_peer_random
309     sm_key_t  sm_local_nonce;   // might be combined with sm_local_random
310     sm_key_t  sm_dhkey;
311     sm_key_t  sm_peer_dhkey_check;
312     sm_key_t  sm_local_dhkey_check;
313     sm_key_t  sm_ra;
314     sm_key_t  sm_rb;
315     sm_key_t  sm_t;             // used for f5 and h6
316     sm_key_t  sm_mackey;
317     uint8_t   sm_passkey_bit;   // also stores number of generated random bytes for EC key generation
318 #endif
319 
320     // Phase 3
321 
322     // key distribution, we generate
323     uint16_t  sm_local_y;
324     uint16_t  sm_local_div;
325     uint16_t  sm_local_ediv;
326     uint8_t   sm_local_rand[8];
327     sm_key_t  sm_local_ltk;
328     sm_key_t  sm_local_csrk;
329     sm_key_t  sm_local_irk;
330     // sm_local_address/addr_type not needed
331 
332     // key distribution, received from peer
333     uint16_t  sm_peer_y;
334     uint16_t  sm_peer_div;
335     uint16_t  sm_peer_ediv;
336     uint8_t   sm_peer_rand[8];
337     sm_key_t  sm_peer_ltk;
338     sm_key_t  sm_peer_irk;
339     sm_key_t  sm_peer_csrk;
340     uint8_t   sm_peer_addr_type;
341     bd_addr_t sm_peer_address;
342 
343 } sm_setup_context_t;
344 
345 //
346 static sm_setup_context_t the_setup;
347 static sm_setup_context_t * setup = &the_setup;
348 
349 // active connection - the one for which the_setup is used for
350 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
351 
352 // @returns 1 if oob data is available
353 // stores oob data in provided 16 byte buffer if not null
354 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL;
355 
356 // horizontal: initiator capabilities
357 // vertial:    responder capabilities
358 static const stk_generation_method_t stk_generation_method [5] [5] = {
359     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
360     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
361     { PK_RESP_INPUT,   PK_RESP_INPUT,    OK_BOTH_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
362     { JUST_WORKS,      JUST_WORKS,       JUST_WORKS,      JUST_WORKS,    JUST_WORKS    },
363     { PK_RESP_INPUT,   PK_RESP_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
364 };
365 
366 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations
367 #ifdef ENABLE_LE_SECURE_CONNECTIONS
368 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = {
369     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
370     { JUST_WORKS,      NK_BOTH_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    NK_BOTH_INPUT },
371     { PK_RESP_INPUT,   PK_RESP_INPUT,    OK_BOTH_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
372     { JUST_WORKS,      JUST_WORKS,       JUST_WORKS,      JUST_WORKS,    JUST_WORKS    },
373     { PK_RESP_INPUT,   NK_BOTH_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    NK_BOTH_INPUT },
374 };
375 #endif
376 
377 static void sm_run(void);
378 static void sm_done_for_handle(hci_con_handle_t con_handle);
379 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle);
380 static inline int sm_calc_actual_encryption_key_size(int other);
381 static int sm_validate_stk_generation_method(void);
382 static void sm_handle_encryption_result(uint8_t * data);
383 
384 static void log_info_hex16(const char * name, uint16_t value){
385     log_info("%-6s 0x%04x", name, value);
386 }
387 
388 // @returns 1 if all bytes are 0
389 static int sm_is_null(uint8_t * data, int size){
390     int i;
391     for (i=0; i < size ; i++){
392         if (data[i]) return 0;
393     }
394     return 1;
395 }
396 
397 static int sm_is_null_random(uint8_t random[8]){
398     return sm_is_null(random, 8);
399 }
400 
401 static int sm_is_null_key(uint8_t * key){
402     return sm_is_null(key, 16);
403 }
404 
405 // Key utils
406 static void sm_reset_tk(void){
407     int i;
408     for (i=0;i<16;i++){
409         setup->sm_tk[i] = 0;
410     }
411 }
412 
413 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0
414 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0.""
415 static void sm_truncate_key(sm_key_t key, int max_encryption_size){
416     int i;
417     for (i = max_encryption_size ; i < 16 ; i++){
418         key[15-i] = 0;
419     }
420 }
421 
422 // SMP Timeout implementation
423 
424 // Upon transmission of the Pairing Request command or reception of the Pairing Request command,
425 // the Security Manager Timer shall be reset and started.
426 //
427 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission.
428 //
429 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed,
430 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP
431 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been
432 // established.
433 
434 static void sm_timeout_handler(btstack_timer_source_t * timer){
435     log_info("SM timeout");
436     sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer);
437     sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT;
438     sm_done_for_handle(sm_conn->sm_handle);
439 
440     // trigger handling of next ready connection
441     sm_run();
442 }
443 static void sm_timeout_start(sm_connection_t * sm_conn){
444     btstack_run_loop_remove_timer(&setup->sm_timeout);
445     btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn);
446     btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler);
447     btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout
448     btstack_run_loop_add_timer(&setup->sm_timeout);
449 }
450 static void sm_timeout_stop(void){
451     btstack_run_loop_remove_timer(&setup->sm_timeout);
452 }
453 static void sm_timeout_reset(sm_connection_t * sm_conn){
454     sm_timeout_stop();
455     sm_timeout_start(sm_conn);
456 }
457 
458 // end of sm timeout
459 
460 // GAP Random Address updates
461 static gap_random_address_type_t gap_random_adress_type;
462 static btstack_timer_source_t gap_random_address_update_timer;
463 static uint32_t gap_random_adress_update_period;
464 
465 static void gap_random_address_trigger(void){
466     if (rau_state != RAU_IDLE) return;
467     log_info("gap_random_address_trigger");
468     rau_state = RAU_GET_RANDOM;
469     sm_run();
470 }
471 
472 static void gap_random_address_update_handler(btstack_timer_source_t * timer){
473     UNUSED(timer);
474 
475     log_info("GAP Random Address Update due");
476     btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period);
477     btstack_run_loop_add_timer(&gap_random_address_update_timer);
478     gap_random_address_trigger();
479 }
480 
481 static void gap_random_address_update_start(void){
482     btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler);
483     btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period);
484     btstack_run_loop_add_timer(&gap_random_address_update_timer);
485 }
486 
487 static void gap_random_address_update_stop(void){
488     btstack_run_loop_remove_timer(&gap_random_address_update_timer);
489 }
490 
491 
492 static void sm_random_start(void * context){
493     sm_random_context = context;
494     hci_send_cmd(&hci_le_rand);
495 }
496 
497 #ifdef HAVE_AES128
498 static void aes128_completed(btstack_timer_source_t * ts){
499     UNUSED(ts);
500     sm_handle_encryption_result(&aes128_result_flipped[0]);
501     sm_run();
502 }
503 #endif
504 
505 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1
506 // context is made availabe to aes128 result handler by this
507 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){
508     sm_aes128_state = SM_AES128_ACTIVE;
509     sm_aes128_context = context;
510 
511 #ifdef HAVE_AES128
512     // calc result directly
513     sm_key_t result;
514     btstack_aes128_calc(key, plaintext, result);
515 
516     // log
517     log_info_key("key", key);
518     log_info_key("txt", plaintext);
519     log_info_key("res", result);
520 
521     // flip
522     reverse_128(&result[0], &aes128_result_flipped[0]);
523 
524     // deliver via timer
525     btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed);
526     btstack_run_loop_set_timer(&aes128_timer, 0);    // no delay
527     btstack_run_loop_add_timer(&aes128_timer);
528 #else
529     sm_key_t key_flipped, plaintext_flipped;
530     reverse_128(key, key_flipped);
531     reverse_128(plaintext, plaintext_flipped);
532     hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped);
533 #endif
534 }
535 
536 // ah(k,r) helper
537 // r = padding || r
538 // r - 24 bit value
539 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){
540     // r'= padding || r
541     memset(r_prime, 0, 16);
542     memcpy(&r_prime[13], r, 3);
543 }
544 
545 // d1 helper
546 // d' = padding || r || d
547 // d,r - 16 bit values
548 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){
549     // d'= padding || r || d
550     memset(d1_prime, 0, 16);
551     big_endian_store_16(d1_prime, 12, r);
552     big_endian_store_16(d1_prime, 14, d);
553 }
554 
555 // dm helper
556 // r’ = padding || r
557 // r - 64 bit value
558 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){
559     memset(r_prime, 0, 16);
560     memcpy(&r_prime[8], r, 8);
561 }
562 
563 // calculate arguments for first AES128 operation in C1 function
564 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){
565 
566     // p1 = pres || preq || rat’ || iat’
567     // "The octet of iat’ becomes the least significant octet of p1 and the most signifi-
568     // cant octet of pres becomes the most significant octet of p1.
569     // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq
570     // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then
571     // p1 is 0x05000800000302070710000001010001."
572 
573     sm_key_t p1;
574     reverse_56(pres, &p1[0]);
575     reverse_56(preq, &p1[7]);
576     p1[14] = rat;
577     p1[15] = iat;
578     log_info_key("p1", p1);
579     log_info_key("r", r);
580 
581     // t1 = r xor p1
582     int i;
583     for (i=0;i<16;i++){
584         t1[i] = r[i] ^ p1[i];
585     }
586     log_info_key("t1", t1);
587 }
588 
589 // calculate arguments for second AES128 operation in C1 function
590 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){
591      // p2 = padding || ia || ra
592     // "The least significant octet of ra becomes the least significant octet of p2 and
593     // the most significant octet of padding becomes the most significant octet of p2.
594     // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is
595     // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6.
596 
597     sm_key_t p2;
598     memset(p2, 0, 16);
599     memcpy(&p2[4],  ia, 6);
600     memcpy(&p2[10], ra, 6);
601     log_info_key("p2", p2);
602 
603     // c1 = e(k, t2_xor_p2)
604     int i;
605     for (i=0;i<16;i++){
606         t3[i] = t2[i] ^ p2[i];
607     }
608     log_info_key("t3", t3);
609 }
610 
611 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){
612     log_info_key("r1", r1);
613     log_info_key("r2", r2);
614     memcpy(&r_prime[8], &r2[8], 8);
615     memcpy(&r_prime[0], &r1[8], 8);
616 }
617 
618 #ifdef ENABLE_LE_SECURE_CONNECTIONS
619 // Software implementations of crypto toolbox for LE Secure Connection
620 // TODO: replace with code to use AES Engine of HCI Controller
621 typedef uint8_t sm_key24_t[3];
622 typedef uint8_t sm_key56_t[7];
623 typedef uint8_t sm_key256_t[32];
624 
625 #if 0
626 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){
627     uint32_t rk[RKLENGTH(KEYBITS)];
628     int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS);
629     rijndaelEncrypt(rk, nrounds, plaintext, cyphertext);
630 }
631 
632 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){
633     memcpy(k1, k0, 16);
634     sm_shift_left_by_one_bit_inplace(16, k1);
635     if (k0[0] & 0x80){
636         k1[15] ^= 0x87;
637     }
638     memcpy(k2, k1, 16);
639     sm_shift_left_by_one_bit_inplace(16, k2);
640     if (k1[0] & 0x80){
641         k2[15] ^= 0x87;
642     }
643 }
644 
645 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){
646     sm_key_t k0, k1, k2, zero;
647     memset(zero, 0, 16);
648 
649     aes128_calc_cyphertext(key, zero, k0);
650     calc_subkeys(k0, k1, k2);
651 
652     int cmac_block_count = (cmac_message_len + 15) / 16;
653 
654     // step 3: ..
655     if (cmac_block_count==0){
656         cmac_block_count = 1;
657     }
658 
659     // step 4: set m_last
660     sm_key_t cmac_m_last;
661     int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0;
662     int i;
663     if (sm_cmac_last_block_complete){
664         for (i=0;i<16;i++){
665             cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i];
666         }
667     } else {
668         int valid_octets_in_last_block = cmac_message_len & 0x0f;
669         for (i=0;i<16;i++){
670             if (i < valid_octets_in_last_block){
671                 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i];
672                 continue;
673             }
674             if (i == valid_octets_in_last_block){
675                 cmac_m_last[i] = 0x80 ^ k2[i];
676                 continue;
677             }
678             cmac_m_last[i] = k2[i];
679         }
680     }
681 
682     // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count);
683     // LOG_KEY(cmac_m_last);
684 
685     // Step 5
686     sm_key_t cmac_x;
687     memset(cmac_x, 0, 16);
688 
689     // Step 6
690     sm_key_t sm_cmac_y;
691     for (int block = 0 ; block < cmac_block_count-1 ; block++){
692         for (i=0;i<16;i++){
693             sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i];
694         }
695         aes128_calc_cyphertext(key, sm_cmac_y, cmac_x);
696     }
697     for (i=0;i<16;i++){
698         sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i];
699     }
700 
701     // Step 7
702     aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac);
703 }
704 #endif
705 #endif
706 
707 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){
708     event[0] = type;
709     event[1] = event_size - 2;
710     little_endian_store_16(event, 2, con_handle);
711     event[4] = addr_type;
712     reverse_bd_addr(address, &event[5]);
713 }
714 
715 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){
716     UNUSED(channel);
717 
718     // log event
719     hci_dump_packet(packet_type, 1, packet, size);
720     // dispatch to all event handlers
721     btstack_linked_list_iterator_t it;
722     btstack_linked_list_iterator_init(&it, &sm_event_handlers);
723     while (btstack_linked_list_iterator_has_next(&it)){
724         btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it);
725         entry->callback(packet_type, 0, packet, size);
726     }
727 }
728 
729 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){
730     uint8_t event[11];
731     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
732     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
733 }
734 
735 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){
736     uint8_t event[15];
737     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
738     little_endian_store_32(event, 11, passkey);
739     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
740 }
741 
742 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){
743     // fetch addr and addr type from db
744     bd_addr_t identity_address;
745     int identity_address_type;
746     le_device_db_info(index, &identity_address_type, identity_address, NULL);
747 
748     uint8_t event[19];
749     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
750     event[11] = identity_address_type;
751     reverse_bd_addr(identity_address, &event[12]);
752     event[18] = index;
753     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
754 }
755 
756 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){
757 
758     uint8_t event[18];
759     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
760     event[11] = result;
761     sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event));
762 }
763 
764 // decide on stk generation based on
765 // - pairing request
766 // - io capabilities
767 // - OOB data availability
768 static void sm_setup_tk(void){
769 
770     // default: just works
771     setup->sm_stk_generation_method = JUST_WORKS;
772 
773 #ifdef ENABLE_LE_SECURE_CONNECTIONS
774     setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq)
775                                        & sm_pairing_packet_get_auth_req(setup->sm_s_pres)
776                                        & SM_AUTHREQ_SECURE_CONNECTION ) != 0;
777     memset(setup->sm_ra, 0, 16);
778     memset(setup->sm_rb, 0, 16);
779 #else
780     setup->sm_use_secure_connections = 0;
781 #endif
782 
783     // If both devices have not set the MITM option in the Authentication Requirements
784     // Flags, then the IO capabilities shall be ignored and the Just Works association
785     // model shall be used.
786     if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0)
787     &&  ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){
788         log_info("SM: MITM not required by both -> JUST WORKS");
789         return;
790     }
791 
792     // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient
793 
794     // If both devices have out of band authentication data, then the Authentication
795     // Requirements Flags shall be ignored when selecting the pairing method and the
796     // Out of Band pairing method shall be used.
797     if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq)
798     &&  sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){
799         log_info("SM: have OOB data");
800         log_info_key("OOB", setup->sm_tk);
801         setup->sm_stk_generation_method = OOB;
802         return;
803     }
804 
805     // Reset TK as it has been setup in sm_init_setup
806     sm_reset_tk();
807 
808     // Also use just works if unknown io capabilites
809     if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){
810         return;
811     }
812 
813     // Otherwise the IO capabilities of the devices shall be used to determine the
814     // pairing method as defined in Table 2.4.
815     // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array
816     const stk_generation_method_t (*generation_method)[5] = stk_generation_method;
817 
818 #ifdef ENABLE_LE_SECURE_CONNECTIONS
819     // table not define by default
820     if (setup->sm_use_secure_connections){
821         generation_method = stk_generation_method_with_secure_connection;
822     }
823 #endif
824     setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)];
825 
826     log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u",
827         sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method);
828 }
829 
830 static int sm_key_distribution_flags_for_set(uint8_t key_set){
831     int flags = 0;
832     if (key_set & SM_KEYDIST_ENC_KEY){
833         flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
834         flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
835     }
836     if (key_set & SM_KEYDIST_ID_KEY){
837         flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
838         flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
839     }
840     if (key_set & SM_KEYDIST_SIGN){
841         flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
842     }
843     return flags;
844 }
845 
846 static void sm_setup_key_distribution(uint8_t key_set){
847     setup->sm_key_distribution_received_set = 0;
848     setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set);
849 }
850 
851 // CSRK Key Lookup
852 
853 
854 static int sm_address_resolution_idle(void){
855     return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE;
856 }
857 
858 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){
859     memcpy(sm_address_resolution_address, addr, 6);
860     sm_address_resolution_addr_type = addr_type;
861     sm_address_resolution_test = 0;
862     sm_address_resolution_mode = mode;
863     sm_address_resolution_context = context;
864     sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr);
865 }
866 
867 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){
868     // check if already in list
869     btstack_linked_list_iterator_t it;
870     sm_lookup_entry_t * entry;
871     btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue);
872     while(btstack_linked_list_iterator_has_next(&it)){
873         entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it);
874         if (entry->address_type != address_type) continue;
875         if (memcmp(entry->address, address, 6))  continue;
876         // already in list
877         return BTSTACK_BUSY;
878     }
879     entry = btstack_memory_sm_lookup_entry_get();
880     if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED;
881     entry->address_type = (bd_addr_type_t) address_type;
882     memcpy(entry->address, address, 6);
883     btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry);
884     sm_run();
885     return 0;
886 }
887 
888 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now
889 static inline void sm_next_responding_state(sm_connection_t * sm_conn){
890     sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1);
891 }
892 static inline void dkg_next_state(void){
893     dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1);
894 }
895 static inline void rau_next_state(void){
896     rau_state = (random_address_update_t) (((int)rau_state) + 1);
897 }
898 
899 // CMAC calculation using AES Engine
900 #ifdef ENABLE_CMAC_ENGINE
901 
902 static inline void sm_cmac_next_state(void){
903     sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1);
904 }
905 
906 static int sm_cmac_last_block_complete(void){
907     if (sm_cmac_message_len == 0) return 0;
908     return (sm_cmac_message_len & 0x0f) == 0;
909 }
910 
911 int sm_cmac_ready(void){
912     return sm_cmac_state == CMAC_IDLE;
913 }
914 
915 // generic cmac calculation
916 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){
917     // Generalized CMAC
918     memcpy(sm_cmac_k, key, 16);
919     memset(sm_cmac_x, 0, 16);
920     sm_cmac_block_current = 0;
921     sm_cmac_message_len  = message_len;
922     sm_cmac_done_handler = done_callback;
923     sm_cmac_get_byte     = get_byte_callback;
924 
925     // step 2: n := ceil(len/const_Bsize);
926     sm_cmac_block_count = (sm_cmac_message_len + 15) / 16;
927 
928     // step 3: ..
929     if (sm_cmac_block_count==0){
930         sm_cmac_block_count = 1;
931     }
932     log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count);
933 
934     // first, we need to compute l for k1, k2, and m_last
935     sm_cmac_state = CMAC_CALC_SUBKEYS;
936 
937     // let's go
938     sm_run();
939 }
940 #endif
941 
942 // cmac for ATT Message signing
943 #ifdef ENABLE_LE_SIGNED_WRITE
944 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){
945     if (offset >= sm_cmac_message_len) {
946         log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len);
947         return 0;
948     }
949 
950     offset = sm_cmac_message_len - 1 - offset;
951 
952     // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4]
953     if (offset < 3){
954         return sm_cmac_header[offset];
955     }
956     int actual_message_len_incl_header = sm_cmac_message_len - 4;
957     if (offset <  actual_message_len_incl_header){
958         return sm_cmac_message[offset - 3];
959     }
960     return sm_cmac_sign_counter[offset - actual_message_len_incl_header];
961 }
962 
963 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){
964     // ATT Message Signing
965     sm_cmac_header[0] = opcode;
966     little_endian_store_16(sm_cmac_header, 1, con_handle);
967     little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter);
968     uint16_t total_message_len = 3 + message_len + 4;  // incl. virtually prepended att opcode, handle and appended sign_counter in LE
969     sm_cmac_message = message;
970     sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler);
971 }
972 #endif
973 
974 #ifdef ENABLE_CMAC_ENGINE
975 static void sm_cmac_handle_aes_engine_ready(void){
976     switch (sm_cmac_state){
977         case CMAC_CALC_SUBKEYS: {
978             sm_key_t const_zero;
979             memset(const_zero, 0, 16);
980             sm_cmac_next_state();
981             sm_aes128_start(sm_cmac_k, const_zero, NULL);
982             break;
983         }
984         case CMAC_CALC_MI: {
985             int j;
986             sm_key_t y;
987             for (j=0;j<16;j++){
988                 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j);
989             }
990             sm_cmac_block_current++;
991             sm_cmac_next_state();
992             sm_aes128_start(sm_cmac_k, y, NULL);
993             break;
994         }
995         case CMAC_CALC_MLAST: {
996             int i;
997             sm_key_t y;
998             for (i=0;i<16;i++){
999                 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i];
1000             }
1001             log_info_key("Y", y);
1002             sm_cmac_block_current++;
1003             sm_cmac_next_state();
1004             sm_aes128_start(sm_cmac_k, y, NULL);
1005             break;
1006         }
1007         default:
1008             log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state);
1009             break;
1010     }
1011 }
1012 
1013 // CMAC Implementation using AES128 engine
1014 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){
1015     int i;
1016     int carry = 0;
1017     for (i=len-1; i >= 0 ; i--){
1018         int new_carry = data[i] >> 7;
1019         data[i] = data[i] << 1 | carry;
1020         carry = new_carry;
1021     }
1022 }
1023 
1024 static void sm_cmac_handle_encryption_result(sm_key_t data){
1025     switch (sm_cmac_state){
1026         case CMAC_W4_SUBKEYS: {
1027             sm_key_t k1;
1028             memcpy(k1, data, 16);
1029             sm_shift_left_by_one_bit_inplace(16, k1);
1030             if (data[0] & 0x80){
1031                 k1[15] ^= 0x87;
1032             }
1033             sm_key_t k2;
1034             memcpy(k2, k1, 16);
1035             sm_shift_left_by_one_bit_inplace(16, k2);
1036             if (k1[0] & 0x80){
1037                 k2[15] ^= 0x87;
1038             }
1039 
1040             log_info_key("k", sm_cmac_k);
1041             log_info_key("k1", k1);
1042             log_info_key("k2", k2);
1043 
1044             // step 4: set m_last
1045             int i;
1046             if (sm_cmac_last_block_complete()){
1047                 for (i=0;i<16;i++){
1048                     sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i];
1049                 }
1050             } else {
1051                 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f;
1052                 for (i=0;i<16;i++){
1053                     if (i < valid_octets_in_last_block){
1054                         sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i];
1055                         continue;
1056                     }
1057                     if (i == valid_octets_in_last_block){
1058                         sm_cmac_m_last[i] = 0x80 ^ k2[i];
1059                         continue;
1060                     }
1061                     sm_cmac_m_last[i] = k2[i];
1062                 }
1063             }
1064 
1065             // next
1066             sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST;
1067             break;
1068         }
1069         case CMAC_W4_MI:
1070             memcpy(sm_cmac_x, data, 16);
1071             sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST;
1072             break;
1073         case CMAC_W4_MLAST:
1074             // done
1075             log_info("Setting CMAC Engine to IDLE");
1076             sm_cmac_state = CMAC_IDLE;
1077             log_info_key("CMAC", data);
1078             sm_cmac_done_handler(data);
1079             break;
1080         default:
1081             log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state);
1082             break;
1083     }
1084 }
1085 #endif
1086 
1087 static void sm_trigger_user_response(sm_connection_t * sm_conn){
1088     // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input
1089     setup->sm_user_response = SM_USER_RESPONSE_IDLE;
1090     switch (setup->sm_stk_generation_method){
1091         case PK_RESP_INPUT:
1092             if (IS_RESPONDER(sm_conn->sm_role)){
1093                 setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1094                 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1095             } else {
1096                 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12));
1097             }
1098             break;
1099         case PK_INIT_INPUT:
1100             if (IS_RESPONDER(sm_conn->sm_role)){
1101                 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12));
1102             } else {
1103                 setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1104                 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1105             }
1106             break;
1107         case OK_BOTH_INPUT:
1108             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1109             sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1110             break;
1111         case NK_BOTH_INPUT:
1112             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1113             sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12));
1114             break;
1115         case JUST_WORKS:
1116             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1117             sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1118             break;
1119         case OOB:
1120             // client already provided OOB data, let's skip notification.
1121             break;
1122     }
1123 }
1124 
1125 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){
1126     int recv_flags;
1127     if (IS_RESPONDER(sm_conn->sm_role)){
1128         // slave / responder
1129         recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres));
1130     } else {
1131         // master / initiator
1132         recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres));
1133     }
1134     log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags);
1135     return recv_flags == setup->sm_key_distribution_received_set;
1136 }
1137 
1138 static void sm_done_for_handle(hci_con_handle_t con_handle){
1139     if (sm_active_connection_handle == con_handle){
1140         sm_timeout_stop();
1141         sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
1142         log_info("sm: connection 0x%x released setup context", con_handle);
1143     }
1144 }
1145 
1146 static int sm_key_distribution_flags_for_auth_req(void){
1147     int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN;
1148     if (sm_auth_req & SM_AUTHREQ_BONDING){
1149         // encryption information only if bonding requested
1150         flags |= SM_KEYDIST_ENC_KEY;
1151     }
1152     return flags;
1153 }
1154 
1155 static void sm_reset_setup(void){
1156     // fill in sm setup
1157     setup->sm_state_vars = 0;
1158     setup->sm_keypress_notification = 0xff;
1159     sm_reset_tk();
1160 }
1161 
1162 static void sm_init_setup(sm_connection_t * sm_conn){
1163 
1164     // fill in sm setup
1165     setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type;
1166     memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6);
1167 
1168     // query client for OOB data
1169     int have_oob_data = 0;
1170     if (sm_get_oob_data) {
1171         have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk);
1172     }
1173 
1174     sm_pairing_packet_t * local_packet;
1175     if (IS_RESPONDER(sm_conn->sm_role)){
1176         // slave
1177         local_packet = &setup->sm_s_pres;
1178         gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address);
1179         setup->sm_m_addr_type = sm_conn->sm_peer_addr_type;
1180         memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6);
1181     } else {
1182         // master
1183         local_packet = &setup->sm_m_preq;
1184         gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address);
1185         setup->sm_s_addr_type = sm_conn->sm_peer_addr_type;
1186         memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6);
1187 
1188         int key_distribution_flags = sm_key_distribution_flags_for_auth_req();
1189         sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags);
1190         sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags);
1191     }
1192 
1193     uint8_t auth_req = sm_auth_req;
1194     sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities);
1195     sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data);
1196     sm_pairing_packet_set_auth_req(*local_packet, auth_req);
1197     sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size);
1198 }
1199 
1200 static int sm_stk_generation_init(sm_connection_t * sm_conn){
1201 
1202     sm_pairing_packet_t * remote_packet;
1203     int                   remote_key_request;
1204     if (IS_RESPONDER(sm_conn->sm_role)){
1205         // slave / responder
1206         remote_packet      = &setup->sm_m_preq;
1207         remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq);
1208     } else {
1209         // master / initiator
1210         remote_packet      = &setup->sm_s_pres;
1211         remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres);
1212     }
1213 
1214     // check key size
1215     sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet));
1216     if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE;
1217 
1218     // decide on STK generation method
1219     sm_setup_tk();
1220     log_info("SMP: generation method %u", setup->sm_stk_generation_method);
1221 
1222     // check if STK generation method is acceptable by client
1223     if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS;
1224 
1225     // identical to responder
1226     sm_setup_key_distribution(remote_key_request);
1227 
1228     // JUST WORKS doens't provide authentication
1229     sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1;
1230 
1231     return 0;
1232 }
1233 
1234 static void sm_address_resolution_handle_event(address_resolution_event_t event){
1235 
1236     // cache and reset context
1237     int matched_device_id = sm_address_resolution_test;
1238     address_resolution_mode_t mode = sm_address_resolution_mode;
1239     void * context = sm_address_resolution_context;
1240 
1241     // reset context
1242     sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE;
1243     sm_address_resolution_context = NULL;
1244     sm_address_resolution_test = -1;
1245     hci_con_handle_t con_handle = 0;
1246 
1247     sm_connection_t * sm_connection;
1248 #ifdef ENABLE_LE_CENTRAL
1249     sm_key_t ltk;
1250 #endif
1251     switch (mode){
1252         case ADDRESS_RESOLUTION_GENERAL:
1253             break;
1254         case ADDRESS_RESOLUTION_FOR_CONNECTION:
1255             sm_connection = (sm_connection_t *) context;
1256             con_handle = sm_connection->sm_handle;
1257             switch (event){
1258                 case ADDRESS_RESOLUTION_SUCEEDED:
1259                     sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED;
1260                     sm_connection->sm_le_db_index = matched_device_id;
1261                     log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index);
1262 #ifdef ENABLE_LE_CENTRAL
1263                     if (sm_connection->sm_role) break;
1264                     if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break;
1265                     sm_connection->sm_security_request_received = 0;
1266                     sm_connection->sm_bonding_requested = 0;
1267                     le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL);
1268                     if (!sm_is_null_key(ltk)){
1269                         sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
1270                     } else {
1271                         sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
1272                     }
1273 #endif
1274                     break;
1275                 case ADDRESS_RESOLUTION_FAILED:
1276                     sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED;
1277 #ifdef ENABLE_LE_CENTRAL
1278                     if (sm_connection->sm_role) break;
1279                     if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break;
1280                     sm_connection->sm_security_request_received = 0;
1281                     sm_connection->sm_bonding_requested = 0;
1282                     sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
1283 #endif
1284                     break;
1285             }
1286             break;
1287         default:
1288             break;
1289     }
1290 
1291     switch (event){
1292         case ADDRESS_RESOLUTION_SUCEEDED:
1293             sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id);
1294             break;
1295         case ADDRESS_RESOLUTION_FAILED:
1296             sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address);
1297             break;
1298     }
1299 }
1300 
1301 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){
1302 
1303     int le_db_index = -1;
1304 
1305     // lookup device based on IRK
1306     if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){
1307         int i;
1308         for (i=0; i < le_device_db_count(); i++){
1309             sm_key_t irk;
1310             bd_addr_t address;
1311             int address_type;
1312             le_device_db_info(i, &address_type, address, irk);
1313             if (memcmp(irk, setup->sm_peer_irk, 16) == 0){
1314                 log_info("sm: device found for IRK, updating");
1315                 le_db_index = i;
1316                 break;
1317             }
1318         }
1319     }
1320 
1321     // if not found, lookup via public address if possible
1322     log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address));
1323     if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){
1324         int i;
1325         for (i=0; i < le_device_db_count(); i++){
1326             bd_addr_t address;
1327             int address_type;
1328             le_device_db_info(i, &address_type, address, NULL);
1329             log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address));
1330             if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){
1331                 log_info("sm: device found for public address, updating");
1332                 le_db_index = i;
1333                 break;
1334             }
1335         }
1336     }
1337 
1338     // if not found, add to db
1339     if (le_db_index < 0) {
1340         le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk);
1341     }
1342 
1343     sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index);
1344 
1345     if (le_db_index >= 0){
1346 
1347 #ifdef ENABLE_LE_SIGNED_WRITE
1348         // store local CSRK
1349         if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
1350             log_info("sm: store local CSRK");
1351             le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk);
1352             le_device_db_local_counter_set(le_db_index, 0);
1353         }
1354 
1355         // store remote CSRK
1356         if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
1357             log_info("sm: store remote CSRK");
1358             le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk);
1359             le_device_db_remote_counter_set(le_db_index, 0);
1360         }
1361 #endif
1362         // store encryption information for secure connections: LTK generated by ECDH
1363         if (setup->sm_use_secure_connections){
1364             log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated);
1365             uint8_t zero_rand[8];
1366             memset(zero_rand, 0, 8);
1367             le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size,
1368                 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED);
1369         }
1370 
1371         // store encryption information for legacy pairing: peer LTK, EDIV, RAND
1372         else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION)
1373                && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){
1374             log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated);
1375             le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk,
1376                 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED);
1377 
1378         }
1379     }
1380 
1381     // keep le_db_index
1382     sm_conn->sm_le_db_index = le_db_index;
1383 }
1384 
1385 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){
1386     setup->sm_pairing_failed_reason = reason;
1387     sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
1388 }
1389 
1390 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){
1391     sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON);
1392 }
1393 
1394 #ifdef ENABLE_LE_SECURE_CONNECTIONS
1395 
1396 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn);
1397 static int sm_passkey_used(stk_generation_method_t method);
1398 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method);
1399 
1400 static void sm_log_ec_keypair(void){
1401     log_info("Elliptic curve: X");
1402     log_info_hexdump(&ec_q[0],32);
1403     log_info("Elliptic curve: Y");
1404     log_info_hexdump(&ec_q[32],32);
1405 }
1406 
1407 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){
1408     if (sm_passkey_used(setup->sm_stk_generation_method)){
1409         sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A;
1410     } else {
1411         sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION;
1412     }
1413 }
1414 
1415 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){
1416     if (IS_RESPONDER(sm_conn->sm_role)){
1417         // Responder
1418         sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM;
1419     } else {
1420         // Initiator role
1421         switch (setup->sm_stk_generation_method){
1422             case JUST_WORKS:
1423                 sm_sc_prepare_dhkey_check(sm_conn);
1424                 break;
1425 
1426             case NK_BOTH_INPUT:
1427                 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2;
1428                 break;
1429             case PK_INIT_INPUT:
1430             case PK_RESP_INPUT:
1431             case OK_BOTH_INPUT:
1432                 if (setup->sm_passkey_bit < 20) {
1433                     sm_sc_start_calculating_local_confirm(sm_conn);
1434                 } else {
1435                     sm_sc_prepare_dhkey_check(sm_conn);
1436                 }
1437                 break;
1438             case OOB:
1439                 // TODO: implement SC OOB
1440                 break;
1441         }
1442     }
1443 }
1444 
1445 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){
1446     return sm_cmac_sc_buffer[offset];
1447 }
1448 
1449 static void sm_sc_cmac_done(uint8_t * hash){
1450     log_info("sm_sc_cmac_done: ");
1451     log_info_hexdump(hash, 16);
1452 
1453     sm_connection_t * sm_conn = sm_cmac_connection;
1454     sm_cmac_connection = NULL;
1455 #ifdef ENABLE_CLASSIC
1456     link_key_type_t link_key_type;
1457 #endif
1458 
1459     switch (sm_conn->sm_engine_state){
1460         case SM_SC_W4_CMAC_FOR_CONFIRMATION:
1461             memcpy(setup->sm_local_confirm, hash, 16);
1462             sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION;
1463             break;
1464         case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION:
1465             // check
1466             if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){
1467                 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED);
1468                 break;
1469             }
1470             sm_sc_state_after_receiving_random(sm_conn);
1471             break;
1472         case SM_SC_W4_CALCULATE_G2: {
1473             uint32_t vab = big_endian_read_32(hash, 12) % 1000000;
1474             big_endian_store_32(setup->sm_tk, 12, vab);
1475             sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
1476             sm_trigger_user_response(sm_conn);
1477             break;
1478         }
1479         case SM_SC_W4_CALCULATE_F5_SALT:
1480             memcpy(setup->sm_t, hash, 16);
1481             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY;
1482             break;
1483         case SM_SC_W4_CALCULATE_F5_MACKEY:
1484             memcpy(setup->sm_mackey, hash, 16);
1485             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK;
1486             break;
1487         case SM_SC_W4_CALCULATE_F5_LTK:
1488             // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk
1489             // Errata Service Release to the Bluetooth Specification: ESR09
1490             //   E6405 – Cross transport key derivation from a key of size less than 128 bits
1491             //   Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked."
1492             memcpy(setup->sm_ltk, hash, 16);
1493             memcpy(setup->sm_local_ltk, hash, 16);
1494             sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size);
1495             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK;
1496             break;
1497         case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK:
1498             memcpy(setup->sm_local_dhkey_check, hash, 16);
1499             if (IS_RESPONDER(sm_conn->sm_role)){
1500                 // responder
1501                 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){
1502                     sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
1503                 } else {
1504                     sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND;
1505                 }
1506             } else {
1507                 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND;
1508             }
1509             break;
1510         case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK:
1511             if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){
1512                 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED);
1513                 break;
1514             }
1515             if (IS_RESPONDER(sm_conn->sm_role)){
1516                 // responder
1517                 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND;
1518             } else {
1519                 // initiator
1520                 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION;
1521             }
1522             break;
1523         case SM_SC_W4_CALCULATE_H6_ILK:
1524             memcpy(setup->sm_t, hash, 16);
1525             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY;
1526             break;
1527         case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY:
1528 #ifdef ENABLE_CLASSIC
1529             reverse_128(hash, setup->sm_t);
1530             link_key_type = sm_conn->sm_connection_authenticated ?
1531                 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256;
1532             log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type);
1533             if (IS_RESPONDER(sm_conn->sm_role)){
1534                 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type);
1535             } else {
1536                 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type);
1537             }
1538 #endif
1539             if (IS_RESPONDER(sm_conn->sm_role)){
1540                 sm_conn->sm_engine_state = SM_RESPONDER_IDLE;
1541             } else {
1542                 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED;
1543             }
1544             sm_done_for_handle(sm_conn->sm_handle);
1545             break;
1546         default:
1547             log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state);
1548             break;
1549     }
1550     sm_run();
1551 }
1552 
1553 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){
1554     const uint16_t message_len = 65;
1555     sm_cmac_connection = sm_conn;
1556     memcpy(sm_cmac_sc_buffer, u, 32);
1557     memcpy(sm_cmac_sc_buffer+32, v, 32);
1558     sm_cmac_sc_buffer[64] = z;
1559     log_info("f4 key");
1560     log_info_hexdump(x, 16);
1561     log_info("f4 message");
1562     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1563     sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1564 }
1565 
1566 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE};
1567 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 };
1568 static const uint8_t f5_length[] = { 0x01, 0x00};
1569 
1570 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1571 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){
1572     memset(dhkey, 0, 32);
1573 #if uECC_SUPPORTS_secp256r1
1574     // standard version
1575     uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1());
1576 #else
1577     // static version
1578     uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey);
1579 #endif
1580     log_info("dhkey");
1581     log_info_hexdump(dhkey, 32);
1582 }
1583 #endif
1584 
1585 static void f5_calculate_salt(sm_connection_t * sm_conn){
1586     // calculate salt for f5
1587     const uint16_t message_len = 32;
1588     sm_cmac_connection = sm_conn;
1589     memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len);
1590     sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1591 }
1592 
1593 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){
1594     const uint16_t message_len = 53;
1595     sm_cmac_connection = sm_conn;
1596 
1597     // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey
1598     sm_cmac_sc_buffer[0] = 0;
1599     memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4);
1600     memcpy(sm_cmac_sc_buffer+05, n1, 16);
1601     memcpy(sm_cmac_sc_buffer+21, n2, 16);
1602     memcpy(sm_cmac_sc_buffer+37, a1, 7);
1603     memcpy(sm_cmac_sc_buffer+44, a2, 7);
1604     memcpy(sm_cmac_sc_buffer+51, f5_length, 2);
1605     log_info("f5 key");
1606     log_info_hexdump(t, 16);
1607     log_info("f5 message for MacKey");
1608     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1609     sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1610 }
1611 
1612 static void f5_calculate_mackey(sm_connection_t * sm_conn){
1613     sm_key56_t bd_addr_master, bd_addr_slave;
1614     bd_addr_master[0] =  setup->sm_m_addr_type;
1615     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1616     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1617     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1618     if (IS_RESPONDER(sm_conn->sm_role)){
1619         // responder
1620         f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave);
1621     } else {
1622         // initiator
1623         f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave);
1624     }
1625 }
1626 
1627 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused
1628 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){
1629     const uint16_t message_len = 53;
1630     sm_cmac_connection = sm_conn;
1631     sm_cmac_sc_buffer[0] = 1;
1632     // 1..52 setup before
1633     log_info("f5 key");
1634     log_info_hexdump(t, 16);
1635     log_info("f5 message for LTK");
1636     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1637     sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1638 }
1639 
1640 static void f5_calculate_ltk(sm_connection_t * sm_conn){
1641     f5_ltk(sm_conn, setup->sm_t);
1642 }
1643 
1644 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){
1645     const uint16_t message_len = 65;
1646     sm_cmac_connection = sm_conn;
1647     memcpy(sm_cmac_sc_buffer, n1, 16);
1648     memcpy(sm_cmac_sc_buffer+16, n2, 16);
1649     memcpy(sm_cmac_sc_buffer+32, r, 16);
1650     memcpy(sm_cmac_sc_buffer+48, io_cap, 3);
1651     memcpy(sm_cmac_sc_buffer+51, a1, 7);
1652     memcpy(sm_cmac_sc_buffer+58, a2, 7);
1653     log_info("f6 key");
1654     log_info_hexdump(w, 16);
1655     log_info("f6 message");
1656     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1657     sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1658 }
1659 
1660 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32
1661 // - U is 256 bits
1662 // - V is 256 bits
1663 // - X is 128 bits
1664 // - Y is 128 bits
1665 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){
1666     const uint16_t message_len = 80;
1667     sm_cmac_connection = sm_conn;
1668     memcpy(sm_cmac_sc_buffer, u, 32);
1669     memcpy(sm_cmac_sc_buffer+32, v, 32);
1670     memcpy(sm_cmac_sc_buffer+64, y, 16);
1671     log_info("g2 key");
1672     log_info_hexdump(x, 16);
1673     log_info("g2 message");
1674     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1675     sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1676 }
1677 
1678 static void g2_calculate(sm_connection_t * sm_conn) {
1679     // calc Va if numeric comparison
1680     if (IS_RESPONDER(sm_conn->sm_role)){
1681         // responder
1682         g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);;
1683     } else {
1684         // initiator
1685         g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce);
1686     }
1687 }
1688 
1689 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){
1690     uint8_t z = 0;
1691     if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){
1692         // some form of passkey
1693         uint32_t pk = big_endian_read_32(setup->sm_tk, 12);
1694         z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1);
1695         setup->sm_passkey_bit++;
1696     }
1697     f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z);
1698 }
1699 
1700 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){
1701     uint8_t z = 0;
1702     if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){
1703         // some form of passkey
1704         uint32_t pk = big_endian_read_32(setup->sm_tk, 12);
1705         // sm_passkey_bit was increased before sending confirm value
1706         z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1);
1707     }
1708     f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z);
1709 }
1710 
1711 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){
1712 
1713 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1714     // calculate DHKEY
1715     sm_sc_calculate_dhkey(setup->sm_dhkey);
1716     setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED;
1717 #endif
1718 
1719     if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){
1720         sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT;
1721         return;
1722     } else {
1723         sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY;
1724     }
1725 
1726 }
1727 
1728 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){
1729     // calculate DHKCheck
1730     sm_key56_t bd_addr_master, bd_addr_slave;
1731     bd_addr_master[0] =  setup->sm_m_addr_type;
1732     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1733     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1734     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1735     uint8_t iocap_a[3];
1736     iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq);
1737     iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq);
1738     iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq);
1739     uint8_t iocap_b[3];
1740     iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres);
1741     iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres);
1742     iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres);
1743     if (IS_RESPONDER(sm_conn->sm_role)){
1744         // responder
1745         f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master);
1746     } else {
1747         // initiator
1748         f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave);
1749     }
1750 }
1751 
1752 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){
1753     // validate E = f6()
1754     sm_key56_t bd_addr_master, bd_addr_slave;
1755     bd_addr_master[0] =  setup->sm_m_addr_type;
1756     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1757     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1758     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1759 
1760     uint8_t iocap_a[3];
1761     iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq);
1762     iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq);
1763     iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq);
1764     uint8_t iocap_b[3];
1765     iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres);
1766     iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres);
1767     iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres);
1768     if (IS_RESPONDER(sm_conn->sm_role)){
1769         // responder
1770         f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave);
1771     } else {
1772         // initiator
1773         f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master);
1774     }
1775 }
1776 
1777 
1778 //
1779 // Link Key Conversion Function h6
1780 //
1781 // h6(W, keyID) = AES-CMACW(keyID)
1782 // - W is 128 bits
1783 // - keyID is 32 bits
1784 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){
1785     const uint16_t message_len = 4;
1786     sm_cmac_connection = sm_conn;
1787     big_endian_store_32(sm_cmac_sc_buffer, 0, key_id);
1788     log_info("h6 key");
1789     log_info_hexdump(w, 16);
1790     log_info("h6 message");
1791     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1792     sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1793 }
1794 
1795 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated)
1796 // Errata Service Release to the Bluetooth Specification: ESR09
1797 //   E6405 – Cross transport key derivation from a key of size less than 128 bits
1798 //   "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked."
1799 static void h6_calculate_ilk(sm_connection_t * sm_conn){
1800     h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031);    // "tmp1"
1801 }
1802 
1803 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){
1804     h6_engine(sm_conn, setup->sm_t, 0x6c656272);    // "lebr"
1805 }
1806 
1807 #endif
1808 
1809 // key management legacy connections:
1810 // - potentially two different LTKs based on direction. each device stores LTK provided by peer
1811 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect)
1812 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder
1813 // - responder  reconnects: responder uses LTK receveived from master
1814 
1815 // key management secure connections:
1816 // - both devices store same LTK from ECDH key exchange.
1817 
1818 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL)
1819 static void sm_load_security_info(sm_connection_t * sm_connection){
1820     int encryption_key_size;
1821     int authenticated;
1822     int authorized;
1823 
1824     // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled
1825     le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk,
1826                                 &encryption_key_size, &authenticated, &authorized);
1827     log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized);
1828     sm_connection->sm_actual_encryption_key_size = encryption_key_size;
1829     sm_connection->sm_connection_authenticated = authenticated;
1830     sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN;
1831 }
1832 #endif
1833 
1834 #ifdef ENABLE_LE_PERIPHERAL
1835 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){
1836     memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8);
1837     setup->sm_local_ediv = sm_connection->sm_local_ediv;
1838     // re-establish used key encryption size
1839     // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand
1840     sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1;
1841     // no db for authenticated flag hack: flag is stored in bit 4 of LSB
1842     sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4;
1843     log_info("sm: received ltk request with key size %u, authenticated %u",
1844             sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated);
1845     sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC;
1846 }
1847 #endif
1848 
1849 static void sm_run(void){
1850 
1851     btstack_linked_list_iterator_t it;
1852 
1853     // assert that stack has already bootet
1854     if (hci_get_state() != HCI_STATE_WORKING) return;
1855 
1856     // assert that we can send at least commands
1857     if (!hci_can_send_command_packet_now()) return;
1858 
1859     //
1860     // non-connection related behaviour
1861     //
1862 
1863     // distributed key generation
1864     switch (dkg_state){
1865         case DKG_CALC_IRK:
1866             // already busy?
1867             if (sm_aes128_state == SM_AES128_IDLE) {
1868                 // IRK = d1(IR, 1, 0)
1869                 sm_key_t d1_prime;
1870                 sm_d1_d_prime(1, 0, d1_prime);  // plaintext
1871                 dkg_next_state();
1872                 sm_aes128_start(sm_persistent_ir, d1_prime, NULL);
1873                 return;
1874             }
1875             break;
1876         case DKG_CALC_DHK:
1877             // already busy?
1878             if (sm_aes128_state == SM_AES128_IDLE) {
1879                 // DHK = d1(IR, 3, 0)
1880                 sm_key_t d1_prime;
1881                 sm_d1_d_prime(3, 0, d1_prime);  // plaintext
1882                 dkg_next_state();
1883                 sm_aes128_start(sm_persistent_ir, d1_prime, NULL);
1884                 return;
1885             }
1886             break;
1887         default:
1888             break;
1889     }
1890 
1891 #ifdef ENABLE_LE_SECURE_CONNECTIONS
1892     if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){
1893 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1894         sm_random_start(NULL);
1895 #else
1896         ec_key_generation_state = EC_KEY_GENERATION_W4_KEY;
1897         hci_send_cmd(&hci_le_read_local_p256_public_key);
1898 #endif
1899         return;
1900     }
1901 #endif
1902 
1903     // random address updates
1904     switch (rau_state){
1905         case RAU_GET_RANDOM:
1906             rau_next_state();
1907             sm_random_start(NULL);
1908             return;
1909         case RAU_GET_ENC:
1910             // already busy?
1911             if (sm_aes128_state == SM_AES128_IDLE) {
1912                 sm_key_t r_prime;
1913                 sm_ah_r_prime(sm_random_address, r_prime);
1914                 rau_next_state();
1915                 sm_aes128_start(sm_persistent_irk, r_prime, NULL);
1916                 return;
1917             }
1918             break;
1919         case RAU_SET_ADDRESS:
1920             log_info("New random address: %s", bd_addr_to_str(sm_random_address));
1921             rau_state = RAU_IDLE;
1922             hci_send_cmd(&hci_le_set_random_address, sm_random_address);
1923             return;
1924         default:
1925             break;
1926     }
1927 
1928 #ifdef ENABLE_CMAC_ENGINE
1929     // CMAC
1930     switch (sm_cmac_state){
1931         case CMAC_CALC_SUBKEYS:
1932         case CMAC_CALC_MI:
1933         case CMAC_CALC_MLAST:
1934             // already busy?
1935             if (sm_aes128_state == SM_AES128_ACTIVE) break;
1936             sm_cmac_handle_aes_engine_ready();
1937             return;
1938         default:
1939             break;
1940     }
1941 #endif
1942 
1943     // CSRK Lookup
1944     // -- if csrk lookup ready, find connection that require csrk lookup
1945     if (sm_address_resolution_idle()){
1946         hci_connections_get_iterator(&it);
1947         while(btstack_linked_list_iterator_has_next(&it)){
1948             hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
1949             sm_connection_t  * sm_connection  = &hci_connection->sm_connection;
1950             if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){
1951                 // and start lookup
1952                 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection);
1953                 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED;
1954                 break;
1955             }
1956         }
1957     }
1958 
1959     // -- if csrk lookup ready, resolved addresses for received addresses
1960     if (sm_address_resolution_idle()) {
1961         if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){
1962             sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue;
1963             btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry);
1964             sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL);
1965             btstack_memory_sm_lookup_entry_free(entry);
1966         }
1967     }
1968 
1969     // -- Continue with CSRK device lookup by public or resolvable private address
1970     if (!sm_address_resolution_idle()){
1971         log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count());
1972         while (sm_address_resolution_test < le_device_db_count()){
1973             int addr_type;
1974             bd_addr_t addr;
1975             sm_key_t irk;
1976             le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk);
1977             log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr));
1978 
1979             if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){
1980                 log_info("LE Device Lookup: found CSRK by { addr_type, address} ");
1981                 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED);
1982                 break;
1983             }
1984 
1985             if (sm_address_resolution_addr_type == 0){
1986                 sm_address_resolution_test++;
1987                 continue;
1988             }
1989 
1990             if (sm_aes128_state == SM_AES128_ACTIVE) break;
1991 
1992             log_info("LE Device Lookup: calculate AH");
1993             log_info_key("IRK", irk);
1994 
1995             sm_key_t r_prime;
1996             sm_ah_r_prime(sm_address_resolution_address, r_prime);
1997             sm_address_resolution_ah_calculation_active = 1;
1998             sm_aes128_start(irk, r_prime, sm_address_resolution_context);   // keep context
1999             return;
2000         }
2001 
2002         if (sm_address_resolution_test >= le_device_db_count()){
2003             log_info("LE Device Lookup: not found");
2004             sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED);
2005         }
2006     }
2007 
2008     // handle basic actions that don't requires the full context
2009     hci_connections_get_iterator(&it);
2010     while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){
2011         hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
2012         sm_connection_t  * sm_connection = &hci_connection->sm_connection;
2013         switch(sm_connection->sm_engine_state){
2014             // responder side
2015             case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY:
2016                 sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2017                 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2018                 return;
2019 
2020 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2021             case SM_SC_RECEIVED_LTK_REQUEST:
2022                 switch (sm_connection->sm_irk_lookup_state){
2023                     case IRK_LOOKUP_FAILED:
2024                         log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)");
2025                         sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2026                         hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2027                         return;
2028                     default:
2029                         break;
2030                 }
2031                 break;
2032 #endif
2033             default:
2034                 break;
2035         }
2036     }
2037 
2038     //
2039     // active connection handling
2040     // -- use loop to handle next connection if lock on setup context is released
2041 
2042     while (1) {
2043 
2044         // Find connections that requires setup context and make active if no other is locked
2045         hci_connections_get_iterator(&it);
2046         while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){
2047             hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
2048             sm_connection_t  * sm_connection = &hci_connection->sm_connection;
2049             // - if no connection locked and we're ready/waiting for setup context, fetch it and start
2050             int done = 1;
2051             int err;
2052             UNUSED(err);
2053             switch (sm_connection->sm_engine_state) {
2054 #ifdef ENABLE_LE_PERIPHERAL
2055                 case SM_RESPONDER_SEND_SECURITY_REQUEST:
2056                     // send packet if possible,
2057                     if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){
2058                         const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING};
2059                         sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST;
2060                         l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2061                     } else {
2062                         l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
2063                     }
2064                     // don't lock sxetup context yet
2065                     done = 0;
2066                     break;
2067                 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED:
2068                     sm_reset_setup();
2069                     sm_init_setup(sm_connection);
2070                     // recover pairing request
2071                     memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t));
2072                     err = sm_stk_generation_init(sm_connection);
2073                     if (err){
2074                         setup->sm_pairing_failed_reason = err;
2075                         sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
2076                         break;
2077                     }
2078                     sm_timeout_start(sm_connection);
2079                     // generate random number first, if we need to show passkey
2080                     if (setup->sm_stk_generation_method == PK_INIT_INPUT){
2081                         sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK;
2082                         break;
2083                     }
2084                     sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE;
2085                     break;
2086                 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST:
2087                     sm_reset_setup();
2088                     sm_start_calculating_ltk_from_ediv_and_rand(sm_connection);
2089                     break;
2090 #endif
2091 #ifdef ENABLE_LE_CENTRAL
2092                 case SM_INITIATOR_PH0_HAS_LTK:
2093                     sm_reset_setup();
2094                     sm_load_security_info(sm_connection);
2095                     sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION;
2096                     break;
2097                 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST:
2098                     sm_reset_setup();
2099                     sm_init_setup(sm_connection);
2100                     sm_timeout_start(sm_connection);
2101                     sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST;
2102                     break;
2103 #endif
2104 
2105 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2106                 case SM_SC_RECEIVED_LTK_REQUEST:
2107                     switch (sm_connection->sm_irk_lookup_state){
2108                         case IRK_LOOKUP_SUCCEEDED:
2109                             // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null
2110                             // start using context by loading security info
2111                             sm_reset_setup();
2112                             sm_load_security_info(sm_connection);
2113                             if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){
2114                                 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16);
2115                                 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY;
2116                                 break;
2117                             }
2118                             log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)");
2119                             sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2120                             hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2121                             // don't lock setup context yet
2122                             return;
2123                         default:
2124                             // just wait until IRK lookup is completed
2125                             // don't lock setup context yet
2126                             done = 0;
2127                             break;
2128                     }
2129                     break;
2130 #endif
2131                 default:
2132                     done = 0;
2133                     break;
2134             }
2135             if (done){
2136                 sm_active_connection_handle = sm_connection->sm_handle;
2137                 log_info("sm: connection 0x%04x locked setup context as %s, state %u", sm_active_connection_handle, sm_connection->sm_role ? "responder" : "initiator", sm_connection->sm_engine_state);
2138             }
2139         }
2140 
2141         //
2142         // active connection handling
2143         //
2144 
2145         if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return;
2146 
2147         sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle);
2148         if (!connection) {
2149             log_info("no connection for handle 0x%04x", sm_active_connection_handle);
2150             return;
2151         }
2152 
2153 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
2154         if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){
2155             setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED;
2156             hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]);
2157             return;
2158         }
2159 #endif
2160 
2161         // assert that we could send a SM PDU - not needed for all of the following
2162         if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) {
2163             log_info("cannot send now, requesting can send now event");
2164             l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
2165             return;
2166         }
2167 
2168         // send keypress notifications
2169         if (setup->sm_keypress_notification != 0xff){
2170             uint8_t buffer[2];
2171             buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION;
2172             buffer[1] = setup->sm_keypress_notification;
2173             setup->sm_keypress_notification = 0xff;
2174             l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2175             return;
2176         }
2177 
2178         sm_key_t plaintext;
2179         int key_distribution_flags;
2180         UNUSED(key_distribution_flags);
2181 
2182         log_info("sm_run: state %u", connection->sm_engine_state);
2183 
2184         switch (connection->sm_engine_state){
2185 
2186             // general
2187             case SM_GENERAL_SEND_PAIRING_FAILED: {
2188                 uint8_t buffer[2];
2189                 buffer[0] = SM_CODE_PAIRING_FAILED;
2190                 buffer[1] = setup->sm_pairing_failed_reason;
2191                 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED;
2192                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2193                 sm_done_for_handle(connection->sm_handle);
2194                 break;
2195             }
2196 
2197             // responding state
2198 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2199             case SM_SC_W2_GET_RANDOM_A:
2200                 sm_random_start(connection);
2201                 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A;
2202                 break;
2203             case SM_SC_W2_GET_RANDOM_B:
2204                 sm_random_start(connection);
2205                 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B;
2206                 break;
2207             case SM_SC_W2_CMAC_FOR_CONFIRMATION:
2208                 if (!sm_cmac_ready()) break;
2209                 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION;
2210                 sm_sc_calculate_local_confirm(connection);
2211                 break;
2212             case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION:
2213                 if (!sm_cmac_ready()) break;
2214                 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION;
2215                 sm_sc_calculate_remote_confirm(connection);
2216                 break;
2217             case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK:
2218                 if (!sm_cmac_ready()) break;
2219                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK;
2220                 sm_sc_calculate_f6_for_dhkey_check(connection);
2221                 break;
2222             case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK:
2223                 if (!sm_cmac_ready()) break;
2224                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
2225                 sm_sc_calculate_f6_to_verify_dhkey_check(connection);
2226                 break;
2227             case SM_SC_W2_CALCULATE_F5_SALT:
2228                 if (!sm_cmac_ready()) break;
2229                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT;
2230                 f5_calculate_salt(connection);
2231                 break;
2232             case SM_SC_W2_CALCULATE_F5_MACKEY:
2233                 if (!sm_cmac_ready()) break;
2234                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY;
2235                 f5_calculate_mackey(connection);
2236                 break;
2237             case SM_SC_W2_CALCULATE_F5_LTK:
2238                 if (!sm_cmac_ready()) break;
2239                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK;
2240                 f5_calculate_ltk(connection);
2241                 break;
2242             case SM_SC_W2_CALCULATE_G2:
2243                 if (!sm_cmac_ready()) break;
2244                 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2;
2245                 g2_calculate(connection);
2246                 break;
2247             case SM_SC_W2_CALCULATE_H6_ILK:
2248                 if (!sm_cmac_ready()) break;
2249                 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK;
2250                 h6_calculate_ilk(connection);
2251                 break;
2252             case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY:
2253                 if (!sm_cmac_ready()) break;
2254                 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY;
2255                 h6_calculate_br_edr_link_key(connection);
2256                 break;
2257 #endif
2258 
2259 #ifdef ENABLE_LE_CENTRAL
2260             // initiator side
2261             case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: {
2262                 sm_key_t peer_ltk_flipped;
2263                 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped);
2264                 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED;
2265                 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv);
2266                 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0);
2267                 uint32_t rand_low  = big_endian_read_32(setup->sm_peer_rand, 4);
2268                 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped);
2269                 return;
2270             }
2271 
2272             case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST:
2273                 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST);
2274                 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE;
2275                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t));
2276                 sm_timeout_reset(connection);
2277                 break;
2278 #endif
2279 
2280 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2281 
2282             case SM_SC_SEND_PUBLIC_KEY_COMMAND: {
2283                 uint8_t buffer[65];
2284                 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY;
2285                 //
2286                 reverse_256(&ec_q[0],  &buffer[1]);
2287                 reverse_256(&ec_q[32], &buffer[33]);
2288 
2289                 // stk generation method
2290                 // passkey entry: notify app to show passkey or to request passkey
2291                 switch (setup->sm_stk_generation_method){
2292                     case JUST_WORKS:
2293                     case NK_BOTH_INPUT:
2294                         if (IS_RESPONDER(connection->sm_role)){
2295                             // responder
2296                             sm_sc_start_calculating_local_confirm(connection);
2297                         } else {
2298                             // initiator
2299                             connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2300                         }
2301                         break;
2302                     case PK_INIT_INPUT:
2303                     case PK_RESP_INPUT:
2304                     case OK_BOTH_INPUT:
2305                         // use random TK for display
2306                         memcpy(setup->sm_ra, setup->sm_tk, 16);
2307                         memcpy(setup->sm_rb, setup->sm_tk, 16);
2308                         setup->sm_passkey_bit = 0;
2309 
2310                         if (IS_RESPONDER(connection->sm_role)){
2311                             // responder
2312                             connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2313                         } else {
2314                             // initiator
2315                             connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2316                         }
2317                         sm_trigger_user_response(connection);
2318                         break;
2319                     case OOB:
2320                         // TODO: implement SC OOB
2321                         break;
2322                 }
2323 
2324                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2325                 sm_timeout_reset(connection);
2326                 break;
2327             }
2328             case SM_SC_SEND_CONFIRMATION: {
2329                 uint8_t buffer[17];
2330                 buffer[0] = SM_CODE_PAIRING_CONFIRM;
2331                 reverse_128(setup->sm_local_confirm, &buffer[1]);
2332                 if (IS_RESPONDER(connection->sm_role)){
2333                     connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2334                 } else {
2335                     connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2336                 }
2337                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2338                 sm_timeout_reset(connection);
2339                 break;
2340             }
2341             case SM_SC_SEND_PAIRING_RANDOM: {
2342                 uint8_t buffer[17];
2343                 buffer[0] = SM_CODE_PAIRING_RANDOM;
2344                 reverse_128(setup->sm_local_nonce, &buffer[1]);
2345                 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){
2346                     if (IS_RESPONDER(connection->sm_role)){
2347                         // responder
2348                         connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2349                     } else {
2350                         // initiator
2351                         connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2352                     }
2353                 } else {
2354                     if (IS_RESPONDER(connection->sm_role)){
2355                         // responder
2356                         if (setup->sm_stk_generation_method == NK_BOTH_INPUT){
2357                             connection->sm_engine_state = SM_SC_W2_CALCULATE_G2;
2358                         } else {
2359                             sm_sc_prepare_dhkey_check(connection);
2360                         }
2361                     } else {
2362                         // initiator
2363                         connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2364                     }
2365                 }
2366                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2367                 sm_timeout_reset(connection);
2368                 break;
2369             }
2370             case SM_SC_SEND_DHKEY_CHECK_COMMAND: {
2371                 uint8_t buffer[17];
2372                 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK;
2373                 reverse_128(setup->sm_local_dhkey_check, &buffer[1]);
2374 
2375                 if (IS_RESPONDER(connection->sm_role)){
2376                     connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC;
2377                 } else {
2378                     connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND;
2379                 }
2380 
2381                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2382                 sm_timeout_reset(connection);
2383                 break;
2384             }
2385 
2386 #endif
2387 
2388 #ifdef ENABLE_LE_PERIPHERAL
2389             case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE:
2390                 // echo initiator for now
2391                 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE);
2392                 key_distribution_flags = sm_key_distribution_flags_for_auth_req();
2393 
2394                 if (setup->sm_use_secure_connections){
2395                     connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2396                     // skip LTK/EDIV for SC
2397                     log_info("sm: dropping encryption information flag");
2398                     key_distribution_flags &= ~SM_KEYDIST_ENC_KEY;
2399                 } else {
2400                     connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM;
2401                 }
2402 
2403                 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags);
2404                 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags);
2405                 // update key distribution after ENC was dropped
2406                 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres));
2407 
2408                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t));
2409                 sm_timeout_reset(connection);
2410                 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged
2411                 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){
2412                     sm_trigger_user_response(connection);
2413                 }
2414                 return;
2415 #endif
2416 
2417             case SM_PH2_SEND_PAIRING_RANDOM: {
2418                 uint8_t buffer[17];
2419                 buffer[0] = SM_CODE_PAIRING_RANDOM;
2420                 reverse_128(setup->sm_local_random, &buffer[1]);
2421                 if (IS_RESPONDER(connection->sm_role)){
2422                     connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST;
2423                 } else {
2424                     connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM;
2425                 }
2426                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2427                 sm_timeout_reset(connection);
2428                 break;
2429             }
2430 
2431             case SM_PH2_GET_RANDOM_TK:
2432             case SM_PH2_C1_GET_RANDOM_A:
2433             case SM_PH2_C1_GET_RANDOM_B:
2434             case SM_PH3_GET_RANDOM:
2435             case SM_PH3_GET_DIV:
2436                 sm_next_responding_state(connection);
2437                 sm_random_start(connection);
2438                 return;
2439 
2440             case SM_PH2_C1_GET_ENC_B:
2441             case SM_PH2_C1_GET_ENC_D:
2442                 // already busy?
2443                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2444                 sm_next_responding_state(connection);
2445                 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection);
2446                 return;
2447 
2448             case SM_PH3_LTK_GET_ENC:
2449             case SM_RESPONDER_PH4_LTK_GET_ENC:
2450                 // already busy?
2451                 if (sm_aes128_state == SM_AES128_IDLE) {
2452                     sm_key_t d_prime;
2453                     sm_d1_d_prime(setup->sm_local_div, 0, d_prime);
2454                     sm_next_responding_state(connection);
2455                     sm_aes128_start(sm_persistent_er, d_prime, connection);
2456                     return;
2457                 }
2458                 break;
2459 
2460             case SM_PH3_CSRK_GET_ENC:
2461                 // already busy?
2462                 if (sm_aes128_state == SM_AES128_IDLE) {
2463                     sm_key_t d_prime;
2464                     sm_d1_d_prime(setup->sm_local_div, 1, d_prime);
2465                     sm_next_responding_state(connection);
2466                     sm_aes128_start(sm_persistent_er, d_prime, connection);
2467                     return;
2468                 }
2469                 break;
2470 
2471             case SM_PH2_C1_GET_ENC_C:
2472                 // already busy?
2473                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2474                 // calculate m_confirm using aes128 engine - step 1
2475                 sm_c1_t1(setup->sm_peer_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext);
2476                 sm_next_responding_state(connection);
2477                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2478                 break;
2479             case SM_PH2_C1_GET_ENC_A:
2480                 // already busy?
2481                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2482                 // calculate confirm using aes128 engine - step 1
2483                 sm_c1_t1(setup->sm_local_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext);
2484                 sm_next_responding_state(connection);
2485                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2486                 break;
2487             case SM_PH2_CALC_STK:
2488                 // already busy?
2489                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2490                 // calculate STK
2491                 if (IS_RESPONDER(connection->sm_role)){
2492                     sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext);
2493                 } else {
2494                     sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext);
2495                 }
2496                 sm_next_responding_state(connection);
2497                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2498                 break;
2499             case SM_PH3_Y_GET_ENC:
2500                 // already busy?
2501                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2502                 // PH3B2 - calculate Y from      - enc
2503                 // Y = dm(DHK, Rand)
2504                 sm_dm_r_prime(setup->sm_local_rand, plaintext);
2505                 sm_next_responding_state(connection);
2506                 sm_aes128_start(sm_persistent_dhk, plaintext, connection);
2507                 return;
2508             case SM_PH2_C1_SEND_PAIRING_CONFIRM: {
2509                 uint8_t buffer[17];
2510                 buffer[0] = SM_CODE_PAIRING_CONFIRM;
2511                 reverse_128(setup->sm_local_confirm, &buffer[1]);
2512                 if (IS_RESPONDER(connection->sm_role)){
2513                     connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM;
2514                 } else {
2515                     connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM;
2516                 }
2517                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2518                 sm_timeout_reset(connection);
2519                 return;
2520             }
2521 #ifdef ENABLE_LE_PERIPHERAL
2522             case SM_RESPONDER_PH2_SEND_LTK_REPLY: {
2523                 sm_key_t stk_flipped;
2524                 reverse_128(setup->sm_ltk, stk_flipped);
2525                 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED;
2526                 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped);
2527                 return;
2528             }
2529             case SM_RESPONDER_PH4_SEND_LTK_REPLY: {
2530                 sm_key_t ltk_flipped;
2531                 reverse_128(setup->sm_ltk, ltk_flipped);
2532                 connection->sm_engine_state = SM_RESPONDER_IDLE;
2533                 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped);
2534                 return;
2535             }
2536             case SM_RESPONDER_PH4_Y_GET_ENC:
2537                 // already busy?
2538                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2539                 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv);
2540                 // Y = dm(DHK, Rand)
2541                 sm_dm_r_prime(setup->sm_local_rand, plaintext);
2542                 sm_next_responding_state(connection);
2543                 sm_aes128_start(sm_persistent_dhk, plaintext, connection);
2544                 return;
2545 #endif
2546 #ifdef ENABLE_LE_CENTRAL
2547             case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: {
2548                 sm_key_t stk_flipped;
2549                 reverse_128(setup->sm_ltk, stk_flipped);
2550                 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED;
2551                 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped);
2552                 return;
2553             }
2554 #endif
2555 
2556             case SM_PH3_DISTRIBUTE_KEYS:
2557                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){
2558                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
2559                     uint8_t buffer[17];
2560                     buffer[0] = SM_CODE_ENCRYPTION_INFORMATION;
2561                     reverse_128(setup->sm_ltk, &buffer[1]);
2562                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2563                     sm_timeout_reset(connection);
2564                     return;
2565                 }
2566                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){
2567                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
2568                     uint8_t buffer[11];
2569                     buffer[0] = SM_CODE_MASTER_IDENTIFICATION;
2570                     little_endian_store_16(buffer, 1, setup->sm_local_ediv);
2571                     reverse_64(setup->sm_local_rand, &buffer[3]);
2572                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2573                     sm_timeout_reset(connection);
2574                     return;
2575                 }
2576                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_IDENTITY_INFORMATION){
2577                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
2578                     uint8_t buffer[17];
2579                     buffer[0] = SM_CODE_IDENTITY_INFORMATION;
2580                     reverse_128(sm_persistent_irk, &buffer[1]);
2581                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2582                     sm_timeout_reset(connection);
2583                     return;
2584                 }
2585                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){
2586                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
2587                     bd_addr_t local_address;
2588                     uint8_t buffer[8];
2589                     buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION;
2590                     switch (gap_random_address_get_mode()){
2591                         case GAP_RANDOM_ADDRESS_TYPE_OFF:
2592                         case GAP_RANDOM_ADDRESS_TYPE_STATIC:
2593                             // public or static random
2594                             gap_le_get_own_address(&buffer[1], local_address);
2595                             break;
2596                         case GAP_RANDOM_ADDRESS_NON_RESOLVABLE:
2597                         case GAP_RANDOM_ADDRESS_RESOLVABLE:
2598                             // fallback to public
2599                             gap_local_bd_addr(local_address);
2600                             buffer[1] = 0;
2601                             break;
2602                     }
2603                     reverse_bd_addr(local_address, &buffer[2]);
2604                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2605                     sm_timeout_reset(connection);
2606                     return;
2607                 }
2608                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
2609                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
2610 
2611                     // hack to reproduce test runs
2612                     if (test_use_fixed_local_csrk){
2613                         memset(setup->sm_local_csrk, 0xcc, 16);
2614                     }
2615 
2616                     uint8_t buffer[17];
2617                     buffer[0] = SM_CODE_SIGNING_INFORMATION;
2618                     reverse_128(setup->sm_local_csrk, &buffer[1]);
2619                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2620                     sm_timeout_reset(connection);
2621                     return;
2622                 }
2623 
2624                 // keys are sent
2625                 if (IS_RESPONDER(connection->sm_role)){
2626                     // slave -> receive master keys if any
2627                     if (sm_key_distribution_all_received(connection)){
2628                         sm_key_distribution_handle_all_received(connection);
2629                         connection->sm_engine_state = SM_RESPONDER_IDLE;
2630                         sm_done_for_handle(connection->sm_handle);
2631                     } else {
2632                         connection->sm_engine_state = SM_PH3_RECEIVE_KEYS;
2633                     }
2634                 } else {
2635                     // master -> all done
2636                     connection->sm_engine_state = SM_INITIATOR_CONNECTED;
2637                     sm_done_for_handle(connection->sm_handle);
2638                 }
2639                 break;
2640 
2641             default:
2642                 break;
2643         }
2644 
2645         // check again if active connection was released
2646         if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break;
2647     }
2648 }
2649 
2650 // note: aes engine is ready as we just got the aes result
2651 static void sm_handle_encryption_result(uint8_t * data){
2652 
2653     sm_aes128_state = SM_AES128_IDLE;
2654 
2655     if (sm_address_resolution_ah_calculation_active){
2656         sm_address_resolution_ah_calculation_active = 0;
2657         // compare calulated address against connecting device
2658         uint8_t hash[3];
2659         reverse_24(data, hash);
2660         if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){
2661             log_info("LE Device Lookup: matched resolvable private address");
2662             sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED);
2663             return;
2664         }
2665         // no match, try next
2666         sm_address_resolution_test++;
2667         return;
2668     }
2669 
2670     switch (dkg_state){
2671         case DKG_W4_IRK:
2672             reverse_128(data, sm_persistent_irk);
2673             log_info_key("irk", sm_persistent_irk);
2674             dkg_next_state();
2675             return;
2676         case DKG_W4_DHK:
2677             reverse_128(data, sm_persistent_dhk);
2678             log_info_key("dhk", sm_persistent_dhk);
2679             dkg_next_state();
2680             // SM Init Finished
2681             return;
2682         default:
2683             break;
2684     }
2685 
2686     switch (rau_state){
2687         case RAU_W4_ENC:
2688             reverse_24(data, &sm_random_address[3]);
2689             rau_next_state();
2690             return;
2691         default:
2692             break;
2693     }
2694 
2695 #ifdef ENABLE_CMAC_ENGINE
2696     switch (sm_cmac_state){
2697         case CMAC_W4_SUBKEYS:
2698         case CMAC_W4_MI:
2699         case CMAC_W4_MLAST:
2700             {
2701             sm_key_t t;
2702             reverse_128(data, t);
2703             sm_cmac_handle_encryption_result(t);
2704             }
2705             return;
2706         default:
2707             break;
2708     }
2709 #endif
2710 
2711     // retrieve sm_connection provided to sm_aes128_start_encryption
2712     sm_connection_t * connection = (sm_connection_t*) sm_aes128_context;
2713     if (!connection) return;
2714     switch (connection->sm_engine_state){
2715         case SM_PH2_C1_W4_ENC_A:
2716         case SM_PH2_C1_W4_ENC_C:
2717             {
2718             sm_key_t t2;
2719             reverse_128(data, t2);
2720             sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value);
2721             }
2722             sm_next_responding_state(connection);
2723             return;
2724         case SM_PH2_C1_W4_ENC_B:
2725             reverse_128(data, setup->sm_local_confirm);
2726             log_info_key("c1!", setup->sm_local_confirm);
2727             connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM;
2728             return;
2729         case SM_PH2_C1_W4_ENC_D:
2730             {
2731             sm_key_t peer_confirm_test;
2732             reverse_128(data, peer_confirm_test);
2733             log_info_key("c1!", peer_confirm_test);
2734             if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){
2735                 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED;
2736                 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
2737                 return;
2738             }
2739             if (IS_RESPONDER(connection->sm_role)){
2740                 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM;
2741             } else {
2742                 connection->sm_engine_state = SM_PH2_CALC_STK;
2743             }
2744             }
2745             return;
2746         case SM_PH2_W4_STK:
2747             reverse_128(data, setup->sm_ltk);
2748             sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size);
2749             log_info_key("stk", setup->sm_ltk);
2750             if (IS_RESPONDER(connection->sm_role)){
2751                 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY;
2752             } else {
2753                 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION;
2754             }
2755             return;
2756         case SM_PH3_Y_W4_ENC:{
2757             sm_key_t y128;
2758             reverse_128(data, y128);
2759             setup->sm_local_y = big_endian_read_16(y128, 14);
2760             log_info_hex16("y", setup->sm_local_y);
2761             // PH3B3 - calculate EDIV
2762             setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div;
2763             log_info_hex16("ediv", setup->sm_local_ediv);
2764             // PH3B4 - calculate LTK         - enc
2765             // LTK = d1(ER, DIV, 0))
2766             connection->sm_engine_state = SM_PH3_LTK_GET_ENC;
2767             return;
2768         }
2769         case SM_RESPONDER_PH4_Y_W4_ENC:{
2770             sm_key_t y128;
2771             reverse_128(data, y128);
2772             setup->sm_local_y = big_endian_read_16(y128, 14);
2773             log_info_hex16("y", setup->sm_local_y);
2774 
2775             // PH3B3 - calculate DIV
2776             setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv;
2777             log_info_hex16("ediv", setup->sm_local_ediv);
2778             // PH3B4 - calculate LTK         - enc
2779             // LTK = d1(ER, DIV, 0))
2780             connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC;
2781             return;
2782         }
2783         case SM_PH3_LTK_W4_ENC:
2784             reverse_128(data, setup->sm_ltk);
2785             log_info_key("ltk", setup->sm_ltk);
2786             // calc CSRK next
2787             connection->sm_engine_state = SM_PH3_CSRK_GET_ENC;
2788             return;
2789         case SM_PH3_CSRK_W4_ENC:
2790             reverse_128(data, setup->sm_local_csrk);
2791             log_info_key("csrk", setup->sm_local_csrk);
2792             if (setup->sm_key_distribution_send_set){
2793                 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS;
2794             } else {
2795                 // no keys to send, just continue
2796                 if (IS_RESPONDER(connection->sm_role)){
2797                     // slave -> receive master keys
2798                     connection->sm_engine_state = SM_PH3_RECEIVE_KEYS;
2799                 } else {
2800                     if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){
2801                         connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK;
2802                     } else {
2803                         // master -> all done
2804                         connection->sm_engine_state = SM_INITIATOR_CONNECTED;
2805                         sm_done_for_handle(connection->sm_handle);
2806                     }
2807                 }
2808             }
2809             return;
2810 #ifdef ENABLE_LE_PERIPHERAL
2811         case SM_RESPONDER_PH4_LTK_W4_ENC:
2812             reverse_128(data, setup->sm_ltk);
2813             sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size);
2814             log_info_key("ltk", setup->sm_ltk);
2815             connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY;
2816             return;
2817 #endif
2818         default:
2819             break;
2820     }
2821 }
2822 
2823 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2824 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
2825 #if !defined(WICED_VERSION)
2826 // @return OK
2827 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){
2828     if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0;
2829     int offset = setup->sm_passkey_bit;
2830     log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset);
2831     while (size) {
2832         *buffer++ = setup->sm_peer_q[offset++];
2833         size--;
2834     }
2835     setup->sm_passkey_bit = offset;
2836     return 1;
2837 }
2838 #endif
2839 #endif
2840 #endif
2841 
2842 // note: random generator is ready. this doesn NOT imply that aes engine is unused!
2843 static void sm_handle_random_result(uint8_t * data){
2844 
2845 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
2846 
2847     if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){
2848         int num_bytes = setup->sm_passkey_bit;
2849         memcpy(&setup->sm_peer_q[num_bytes], data, 8);
2850         num_bytes += 8;
2851         setup->sm_passkey_bit = num_bytes;
2852 
2853         if (num_bytes >= 64){
2854 
2855             // init pre-generated random data from sm_peer_q
2856             setup->sm_passkey_bit = 0;
2857 
2858             // generate EC key
2859 #ifndef WICED_VERSION
2860             log_info("set uECC RNG for initial key generation with 64 random bytes");
2861             // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it
2862             uECC_set_rng(&sm_generate_f_rng);
2863 #endif /* WICED_VERSION */
2864 
2865 #if uECC_SUPPORTS_secp256r1
2866             // standard version
2867             uECC_make_key(ec_q, ec_d, uECC_secp256r1());
2868 
2869             // disable RNG again, as returning no randmon data lets shared key generation fail
2870             log_info("disable uECC RNG in standard version after key generation");
2871             uECC_set_rng(NULL);
2872 #else
2873             // static version
2874             uECC_make_key(ec_q, ec_d);
2875 #endif /* ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS */
2876 
2877             ec_key_generation_state = EC_KEY_GENERATION_DONE;
2878             log_info("Elliptic curve: d");
2879             log_info_hexdump(ec_d,32);
2880             sm_log_ec_keypair();
2881         }
2882     }
2883 #endif
2884 
2885     switch (rau_state){
2886         case RAU_W4_RANDOM:
2887             // non-resolvable vs. resolvable
2888             switch (gap_random_adress_type){
2889                 case GAP_RANDOM_ADDRESS_RESOLVABLE:
2890                     // resolvable: use random as prand and calc address hash
2891                     // "The two most significant bits of prand shall be equal to ‘0’ and ‘1"
2892                     memcpy(sm_random_address, data, 3);
2893                     sm_random_address[0] &= 0x3f;
2894                     sm_random_address[0] |= 0x40;
2895                     rau_state = RAU_GET_ENC;
2896                     break;
2897                 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE:
2898                 default:
2899                     // "The two most significant bits of the address shall be equal to ‘0’""
2900                     memcpy(sm_random_address, data, 6);
2901                     sm_random_address[0] &= 0x3f;
2902                     rau_state = RAU_SET_ADDRESS;
2903                     break;
2904             }
2905             return;
2906         default:
2907             break;
2908     }
2909 
2910     // retrieve sm_connection provided to sm_random_start
2911     sm_connection_t * connection = (sm_connection_t *) sm_random_context;
2912     if (!connection) return;
2913     switch (connection->sm_engine_state){
2914 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2915         case SM_SC_W4_GET_RANDOM_A:
2916             memcpy(&setup->sm_local_nonce[0], data, 8);
2917             connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B;
2918             break;
2919         case SM_SC_W4_GET_RANDOM_B:
2920             memcpy(&setup->sm_local_nonce[8], data, 8);
2921             // initiator & jw/nc -> send pairing random
2922             if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){
2923                 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM;
2924                 break;
2925             } else {
2926                 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION;
2927             }
2928             break;
2929 #endif
2930 
2931         case SM_PH2_W4_RANDOM_TK:
2932         {
2933             // map random to 0-999999 without speding much cycles on a modulus operation
2934             uint32_t tk = little_endian_read_32(data,0);
2935             tk = tk & 0xfffff;  // 1048575
2936             if (tk >= 999999){
2937                 tk = tk - 999999;
2938             }
2939             sm_reset_tk();
2940             big_endian_store_32(setup->sm_tk, 12, tk);
2941             if (IS_RESPONDER(connection->sm_role)){
2942                 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE;
2943             } else {
2944                 if (setup->sm_use_secure_connections){
2945                     connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
2946                 } else {
2947                     connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
2948                     sm_trigger_user_response(connection);
2949                     // response_idle == nothing <--> sm_trigger_user_response() did not require response
2950                     if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){
2951                         connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
2952                     }
2953                 }
2954             }
2955             return;
2956         }
2957         case SM_PH2_C1_W4_RANDOM_A:
2958             memcpy(&setup->sm_local_random[0], data, 8); // random endinaness
2959             connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B;
2960             return;
2961         case SM_PH2_C1_W4_RANDOM_B:
2962             memcpy(&setup->sm_local_random[8], data, 8); // random endinaness
2963             connection->sm_engine_state = SM_PH2_C1_GET_ENC_A;
2964             return;
2965         case SM_PH3_W4_RANDOM:
2966             reverse_64(data, setup->sm_local_rand);
2967             // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand
2968             setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1);
2969             // no db for authenticated flag hack: store flag in bit 4 of LSB
2970             setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4);
2971             connection->sm_engine_state = SM_PH3_GET_DIV;
2972             return;
2973         case SM_PH3_W4_DIV:
2974             // use 16 bit from random value as div
2975             setup->sm_local_div = big_endian_read_16(data, 0);
2976             log_info_hex16("div", setup->sm_local_div);
2977             connection->sm_engine_state = SM_PH3_Y_GET_ENC;
2978             return;
2979         default:
2980             break;
2981     }
2982 }
2983 
2984 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
2985 
2986     UNUSED(channel);
2987     UNUSED(size);
2988 
2989     sm_connection_t  * sm_conn;
2990     hci_con_handle_t con_handle;
2991 
2992     switch (packet_type) {
2993 
2994 		case HCI_EVENT_PACKET:
2995 			switch (hci_event_packet_get_type(packet)) {
2996 
2997                 case BTSTACK_EVENT_STATE:
2998 					// bt stack activated, get started
2999 					if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){
3000                         log_info("HCI Working!");
3001 
3002 
3003                         dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK;
3004 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3005                         if (!sm_have_ec_keypair){
3006                             setup->sm_passkey_bit = 0;
3007                             ec_key_generation_state = EC_KEY_GENERATION_ACTIVE;
3008                         }
3009 #endif
3010                         // trigger Random Address generation if requested before
3011                         switch (gap_random_adress_type){
3012                             case GAP_RANDOM_ADDRESS_TYPE_OFF:
3013                                 rau_state = RAU_IDLE;
3014                                 break;
3015                             case GAP_RANDOM_ADDRESS_TYPE_STATIC:
3016                                 rau_state = RAU_SET_ADDRESS;
3017                                 break;
3018                             default:
3019                                 rau_state = RAU_GET_RANDOM;
3020                                 break;
3021                         }
3022                         sm_run();
3023 					}
3024 					break;
3025 
3026                 case HCI_EVENT_LE_META:
3027                     switch (packet[2]) {
3028                         case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
3029 
3030                             log_info("sm: connected");
3031 
3032                             if (packet[3]) return; // connection failed
3033 
3034                             con_handle = little_endian_read_16(packet, 4);
3035                             sm_conn = sm_get_connection_for_handle(con_handle);
3036                             if (!sm_conn) break;
3037 
3038                             sm_conn->sm_handle = con_handle;
3039                             sm_conn->sm_role = packet[6];
3040                             sm_conn->sm_peer_addr_type = packet[7];
3041                             reverse_bd_addr(&packet[8], sm_conn->sm_peer_address);
3042 
3043                             log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master");
3044 
3045                             // reset security properties
3046                             sm_conn->sm_connection_encrypted = 0;
3047                             sm_conn->sm_connection_authenticated = 0;
3048                             sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN;
3049                             sm_conn->sm_le_db_index = -1;
3050 
3051                             // prepare CSRK lookup (does not involve setup)
3052                             sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY;
3053 
3054                             // just connected -> everything else happens in sm_run()
3055                             if (IS_RESPONDER(sm_conn->sm_role)){
3056                                 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead
3057                                 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){
3058                                     if (sm_slave_request_security) {
3059                                         // request security if requested by app
3060                                         sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST;
3061                                     } else {
3062                                         // otherwise, wait for pairing request
3063                                         sm_conn->sm_engine_state = SM_RESPONDER_IDLE;
3064                                     }
3065                                 }
3066                                 break;
3067                             } else {
3068                                 // master
3069                                 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED;
3070                             }
3071                             break;
3072 
3073                         case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST:
3074                             con_handle = little_endian_read_16(packet, 3);
3075                             sm_conn = sm_get_connection_for_handle(con_handle);
3076                             if (!sm_conn) break;
3077 
3078                             log_info("LTK Request: state %u", sm_conn->sm_engine_state);
3079                             if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){
3080                                 sm_conn->sm_engine_state = SM_PH2_CALC_STK;
3081                                 break;
3082                             }
3083                             if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){
3084                                 // PH2 SEND LTK as we need to exchange keys in PH3
3085                                 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY;
3086                                 break;
3087                             }
3088 
3089                             // store rand and ediv
3090                             reverse_64(&packet[5], sm_conn->sm_local_rand);
3091                             sm_conn->sm_local_ediv = little_endian_read_16(packet, 13);
3092 
3093                             // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a
3094                             // potentially stored LTK is from the master
3095                             if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){
3096                                 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST;
3097                                 break;
3098                             }
3099 
3100 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3101                             sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST;
3102 #else
3103                             log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported");
3104                             sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY;
3105 #endif
3106                             break;
3107 
3108 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
3109                         case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE:
3110                             if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){
3111                                 log_error("Read Local P256 Public Key failed");
3112                                 break;
3113                             }
3114 
3115                             hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]);
3116                             hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]);
3117 
3118                             ec_key_generation_state = EC_KEY_GENERATION_DONE;
3119                             sm_log_ec_keypair();
3120                             break;
3121                         case HCI_SUBEVENT_LE_GENERATE_DHKEY_COMPLETE:
3122                             sm_conn = sm_get_connection_for_handle(sm_active_connection_handle);
3123                             if (hci_subevent_le_generate_dhkey_complete_get_status(packet)){
3124                                 log_error("Generate DHKEY failed -> abort");
3125                                 // abort pairing with 'unspecified reason'
3126                                 sm_pdu_received_in_wrong_state(sm_conn);
3127                                 break;
3128                             }
3129 
3130                             hci_subevent_le_generate_dhkey_complete_get_dhkey(packet, &setup->sm_dhkey[0]);
3131                             setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED;
3132                             log_info("dhkey");
3133                             log_info_hexdump(&setup->sm_dhkey[0], 32);
3134 
3135                             // trigger next step
3136                             if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){
3137                                 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT;
3138                             }
3139                             break;
3140 #endif
3141                         default:
3142                             break;
3143                     }
3144                     break;
3145 
3146                 case HCI_EVENT_ENCRYPTION_CHANGE:
3147                     con_handle = little_endian_read_16(packet, 3);
3148                     sm_conn = sm_get_connection_for_handle(con_handle);
3149                     if (!sm_conn) break;
3150 
3151                     sm_conn->sm_connection_encrypted = packet[5];
3152                     log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted,
3153                         sm_conn->sm_actual_encryption_key_size);
3154                     log_info("event handler, state %u", sm_conn->sm_engine_state);
3155                     if (!sm_conn->sm_connection_encrypted) break;
3156                     // continue if part of initial pairing
3157                     switch (sm_conn->sm_engine_state){
3158                         case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED:
3159                             sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED;
3160                             sm_done_for_handle(sm_conn->sm_handle);
3161                             break;
3162                         case SM_PH2_W4_CONNECTION_ENCRYPTED:
3163                             if (IS_RESPONDER(sm_conn->sm_role)){
3164                                 // slave
3165                                 if (setup->sm_use_secure_connections){
3166                                     sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS;
3167                                 } else {
3168                                     sm_conn->sm_engine_state = SM_PH3_GET_RANDOM;
3169                                 }
3170                             } else {
3171                                 // master
3172                                 if (sm_key_distribution_all_received(sm_conn)){
3173                                     // skip receiving keys as there are none
3174                                     sm_key_distribution_handle_all_received(sm_conn);
3175                                     sm_conn->sm_engine_state = SM_PH3_GET_RANDOM;
3176                                 } else {
3177                                     sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS;
3178                                 }
3179                             }
3180                             break;
3181                         default:
3182                             break;
3183                     }
3184                     break;
3185 
3186                 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE:
3187                     con_handle = little_endian_read_16(packet, 3);
3188                     sm_conn = sm_get_connection_for_handle(con_handle);
3189                     if (!sm_conn) break;
3190 
3191                     log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size);
3192                     log_info("event handler, state %u", sm_conn->sm_engine_state);
3193                     // continue if part of initial pairing
3194                     switch (sm_conn->sm_engine_state){
3195                         case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED:
3196                             sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED;
3197                             sm_done_for_handle(sm_conn->sm_handle);
3198                             break;
3199                         case SM_PH2_W4_CONNECTION_ENCRYPTED:
3200                             if (IS_RESPONDER(sm_conn->sm_role)){
3201                                 // slave
3202                                 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM;
3203                             } else {
3204                                 // master
3205                                 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS;
3206                             }
3207                             break;
3208                         default:
3209                             break;
3210                     }
3211                     break;
3212 
3213 
3214                 case HCI_EVENT_DISCONNECTION_COMPLETE:
3215                     con_handle = little_endian_read_16(packet, 3);
3216                     sm_done_for_handle(con_handle);
3217                     sm_conn = sm_get_connection_for_handle(con_handle);
3218                     if (!sm_conn) break;
3219 
3220                     // delete stored bonding on disconnect with authentication failure in ph0
3221                     if (sm_conn->sm_role == 0
3222                         && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED
3223                         && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){
3224                         le_device_db_remove(sm_conn->sm_le_db_index);
3225                     }
3226 
3227                     sm_conn->sm_engine_state = SM_GENERAL_IDLE;
3228                     sm_conn->sm_handle = 0;
3229                     break;
3230 
3231 				case HCI_EVENT_COMMAND_COMPLETE:
3232                     if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){
3233                         sm_handle_encryption_result(&packet[6]);
3234                         break;
3235                     }
3236                     if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){
3237                         sm_handle_random_result(&packet[6]);
3238                         break;
3239                     }
3240                     if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){
3241                         // Hack for Nordic nRF5 series that doesn't have public address:
3242                         // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address
3243                         // - we use this as default for advertisements/connections
3244                         bd_addr_t addr;
3245                         reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr);
3246                         if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){
3247                             log_info("nRF5: using (fake) public address as random static address");
3248                             gap_random_address_set(addr);
3249                         }
3250 
3251                         // set local addr for le device db
3252                         le_device_db_set_local_bd_addr(addr);
3253                     }
3254                     if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_local_supported_commands)){
3255 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
3256                         if ((packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE+1+34] & 0x06) != 0x06){
3257                             log_error("LE Secure Connections enabled, but HCI Controller doesn't support it. Please add ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS to btstack_config.h");
3258                         }
3259 #endif
3260                     }
3261                     break;
3262                 default:
3263                     break;
3264 			}
3265             break;
3266         default:
3267             break;
3268 	}
3269 
3270     sm_run();
3271 }
3272 
3273 static inline int sm_calc_actual_encryption_key_size(int other){
3274     if (other < sm_min_encryption_key_size) return 0;
3275     if (other < sm_max_encryption_key_size) return other;
3276     return sm_max_encryption_key_size;
3277 }
3278 
3279 
3280 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3281 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){
3282     switch (method){
3283         case JUST_WORKS:
3284         case NK_BOTH_INPUT:
3285             return 1;
3286         default:
3287             return 0;
3288     }
3289 }
3290 // responder
3291 
3292 static int sm_passkey_used(stk_generation_method_t method){
3293     switch (method){
3294         case PK_RESP_INPUT:
3295             return 1;
3296         default:
3297             return 0;
3298     }
3299 }
3300 #endif
3301 
3302 /**
3303  * @return ok
3304  */
3305 static int sm_validate_stk_generation_method(void){
3306     // check if STK generation method is acceptable by client
3307     switch (setup->sm_stk_generation_method){
3308         case JUST_WORKS:
3309             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0;
3310         case PK_RESP_INPUT:
3311         case PK_INIT_INPUT:
3312         case OK_BOTH_INPUT:
3313             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0;
3314         case OOB:
3315             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0;
3316         case NK_BOTH_INPUT:
3317             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0;
3318             return 1;
3319         default:
3320             return 0;
3321     }
3322 }
3323 
3324 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){
3325 
3326     UNUSED(size);
3327 
3328     if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){
3329         sm_run();
3330     }
3331 
3332     if (packet_type != SM_DATA_PACKET) return;
3333 
3334     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3335     if (!sm_conn) return;
3336 
3337     if (packet[0] == SM_CODE_PAIRING_FAILED){
3338         sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED;
3339         return;
3340     }
3341 
3342     log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]);
3343 
3344     int err;
3345     UNUSED(err);
3346 
3347     if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){
3348         uint8_t buffer[5];
3349         buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION;
3350         buffer[1] = 3;
3351         little_endian_store_16(buffer, 2, con_handle);
3352         buffer[4] = packet[1];
3353         sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer));
3354         return;
3355     }
3356 
3357     switch (sm_conn->sm_engine_state){
3358 
3359         // a sm timeout requries a new physical connection
3360         case SM_GENERAL_TIMEOUT:
3361             return;
3362 
3363 #ifdef ENABLE_LE_CENTRAL
3364 
3365         // Initiator
3366         case SM_INITIATOR_CONNECTED:
3367             if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){
3368                 sm_pdu_received_in_wrong_state(sm_conn);
3369                 break;
3370             }
3371             if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){
3372                 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3373                 break;
3374             }
3375             if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){
3376                 sm_key_t ltk;
3377                 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL);
3378                 if (!sm_is_null_key(ltk)){
3379                     log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index);
3380                     sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
3381                 } else {
3382                     sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3383                 }
3384                 break;
3385             }
3386             // otherwise, store security request
3387             sm_conn->sm_security_request_received = 1;
3388             break;
3389 
3390         case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE:
3391             if (packet[0] != SM_CODE_PAIRING_RESPONSE){
3392                 sm_pdu_received_in_wrong_state(sm_conn);
3393                 break;
3394             }
3395             // store pairing request
3396             memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t));
3397             err = sm_stk_generation_init(sm_conn);
3398             if (err){
3399                 setup->sm_pairing_failed_reason = err;
3400                 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
3401                 break;
3402             }
3403 
3404             // generate random number first, if we need to show passkey
3405             if (setup->sm_stk_generation_method == PK_RESP_INPUT){
3406                 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK;
3407                 break;
3408             }
3409 
3410 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3411             if (setup->sm_use_secure_connections){
3412                 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged
3413                 if (setup->sm_stk_generation_method == JUST_WORKS){
3414                     sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3415                     sm_trigger_user_response(sm_conn);
3416                     if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){
3417                         sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3418                     }
3419                 } else {
3420                     sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3421                 }
3422                 break;
3423             }
3424 #endif
3425             sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3426             sm_trigger_user_response(sm_conn);
3427             // response_idle == nothing <--> sm_trigger_user_response() did not require response
3428             if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){
3429                 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3430             }
3431             break;
3432 
3433         case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM:
3434             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3435                 sm_pdu_received_in_wrong_state(sm_conn);
3436                 break;
3437             }
3438 
3439             // store s_confirm
3440             reverse_128(&packet[1], setup->sm_peer_confirm);
3441             sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM;
3442             break;
3443 
3444         case SM_INITIATOR_PH2_W4_PAIRING_RANDOM:
3445             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3446                 sm_pdu_received_in_wrong_state(sm_conn);
3447                 break;;
3448             }
3449 
3450             // received random value
3451             reverse_128(&packet[1], setup->sm_peer_random);
3452             sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C;
3453             break;
3454 #endif
3455 
3456 #ifdef ENABLE_LE_PERIPHERAL
3457         // Responder
3458         case SM_RESPONDER_IDLE:
3459         case SM_RESPONDER_SEND_SECURITY_REQUEST:
3460         case SM_RESPONDER_PH1_W4_PAIRING_REQUEST:
3461             if (packet[0] != SM_CODE_PAIRING_REQUEST){
3462                 sm_pdu_received_in_wrong_state(sm_conn);
3463                 break;;
3464             }
3465 
3466             // store pairing request
3467             memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t));
3468             sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED;
3469             break;
3470 #endif
3471 
3472 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3473         case SM_SC_W4_PUBLIC_KEY_COMMAND:
3474             if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){
3475                 sm_pdu_received_in_wrong_state(sm_conn);
3476                 break;
3477             }
3478 
3479             // store public key for DH Key calculation
3480             reverse_256(&packet[01], &setup->sm_peer_q[0]);
3481             reverse_256(&packet[33], &setup->sm_peer_q[32]);
3482 
3483 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
3484             // validate public key
3485             err = 0;
3486 #if uECC_SUPPORTS_secp256r1
3487             // standard version
3488             err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0;
3489 #else
3490             // static version
3491             err = uECC_valid_public_key(setup->sm_peer_q) == 0;
3492 #endif
3493             if (err){
3494                 log_error("sm: peer public key invalid %x", err);
3495                 // uses "unspecified reason", there is no "public key invalid" error code
3496                 sm_pdu_received_in_wrong_state(sm_conn);
3497                 break;
3498             }
3499 #endif
3500 
3501 #ifndef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
3502             // start calculating dhkey
3503             setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED;
3504 #endif
3505 
3506             if (IS_RESPONDER(sm_conn->sm_role)){
3507                 // responder
3508                 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3509             } else {
3510                 // initiator
3511                 // stk generation method
3512                 // passkey entry: notify app to show passkey or to request passkey
3513                 switch (setup->sm_stk_generation_method){
3514                     case JUST_WORKS:
3515                     case NK_BOTH_INPUT:
3516                         sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION;
3517                         break;
3518                     case PK_RESP_INPUT:
3519                         sm_sc_start_calculating_local_confirm(sm_conn);
3520                         break;
3521                     case PK_INIT_INPUT:
3522                     case OK_BOTH_INPUT:
3523                         if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){
3524                             sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
3525                             break;
3526                         }
3527                         sm_sc_start_calculating_local_confirm(sm_conn);
3528                         break;
3529                     case OOB:
3530                         // TODO: implement SC OOB
3531                         break;
3532                 }
3533             }
3534             break;
3535 
3536         case SM_SC_W4_CONFIRMATION:
3537             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3538                 sm_pdu_received_in_wrong_state(sm_conn);
3539                 break;
3540             }
3541             // received confirm value
3542             reverse_128(&packet[1], setup->sm_peer_confirm);
3543 
3544             if (IS_RESPONDER(sm_conn->sm_role)){
3545                 // responder
3546                 if (sm_passkey_used(setup->sm_stk_generation_method)){
3547                     if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){
3548                         // still waiting for passkey
3549                         sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
3550                         break;
3551                     }
3552                 }
3553                 sm_sc_start_calculating_local_confirm(sm_conn);
3554             } else {
3555                 // initiator
3556                 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){
3557                     sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A;
3558                 } else {
3559                     sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM;
3560                 }
3561             }
3562             break;
3563 
3564         case SM_SC_W4_PAIRING_RANDOM:
3565             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3566                 sm_pdu_received_in_wrong_state(sm_conn);
3567                 break;
3568             }
3569 
3570             // received random value
3571             reverse_128(&packet[1], setup->sm_peer_nonce);
3572 
3573             // validate confirm value if Cb = f4(Pkb, Pka, Nb, z)
3574             // only check for JUST WORK/NC in initiator role AND passkey entry
3575             if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) {
3576                  sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION;
3577             }
3578 
3579             sm_sc_state_after_receiving_random(sm_conn);
3580             break;
3581 
3582         case SM_SC_W2_CALCULATE_G2:
3583         case SM_SC_W4_CALCULATE_G2:
3584         case SM_SC_W4_CALCULATE_DHKEY:
3585         case SM_SC_W2_CALCULATE_F5_SALT:
3586         case SM_SC_W4_CALCULATE_F5_SALT:
3587         case SM_SC_W2_CALCULATE_F5_MACKEY:
3588         case SM_SC_W4_CALCULATE_F5_MACKEY:
3589         case SM_SC_W2_CALCULATE_F5_LTK:
3590         case SM_SC_W4_CALCULATE_F5_LTK:
3591         case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK:
3592         case SM_SC_W4_DHKEY_CHECK_COMMAND:
3593         case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK:
3594             if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){
3595                 sm_pdu_received_in_wrong_state(sm_conn);
3596                 break;
3597             }
3598             // store DHKey Check
3599             setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED;
3600             reverse_128(&packet[01], setup->sm_peer_dhkey_check);
3601 
3602             // have we been only waiting for dhkey check command?
3603             if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){
3604                 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
3605             }
3606             break;
3607 #endif
3608 
3609 #ifdef ENABLE_LE_PERIPHERAL
3610         case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM:
3611             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3612                 sm_pdu_received_in_wrong_state(sm_conn);
3613                 break;
3614             }
3615 
3616             // received confirm value
3617             reverse_128(&packet[1], setup->sm_peer_confirm);
3618 
3619             // notify client to hide shown passkey
3620             if (setup->sm_stk_generation_method == PK_INIT_INPUT){
3621                 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
3622             }
3623 
3624             // handle user cancel pairing?
3625             if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){
3626                 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED;
3627                 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
3628                 break;
3629             }
3630 
3631             // wait for user action?
3632             if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){
3633                 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3634                 break;
3635             }
3636 
3637             // calculate and send local_confirm
3638             sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3639             break;
3640 
3641         case SM_RESPONDER_PH2_W4_PAIRING_RANDOM:
3642             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3643                 sm_pdu_received_in_wrong_state(sm_conn);
3644                 break;;
3645             }
3646 
3647             // received random value
3648             reverse_128(&packet[1], setup->sm_peer_random);
3649             sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C;
3650             break;
3651 #endif
3652 
3653         case SM_PH3_RECEIVE_KEYS:
3654             switch(packet[0]){
3655                 case SM_CODE_ENCRYPTION_INFORMATION:
3656                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
3657                     reverse_128(&packet[1], setup->sm_peer_ltk);
3658                     break;
3659 
3660                 case SM_CODE_MASTER_IDENTIFICATION:
3661                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
3662                     setup->sm_peer_ediv = little_endian_read_16(packet, 1);
3663                     reverse_64(&packet[3], setup->sm_peer_rand);
3664                     break;
3665 
3666                 case SM_CODE_IDENTITY_INFORMATION:
3667                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
3668                     reverse_128(&packet[1], setup->sm_peer_irk);
3669                     break;
3670 
3671                 case SM_CODE_IDENTITY_ADDRESS_INFORMATION:
3672                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
3673                     setup->sm_peer_addr_type = packet[1];
3674                     reverse_bd_addr(&packet[2], setup->sm_peer_address);
3675                     break;
3676 
3677                 case SM_CODE_SIGNING_INFORMATION:
3678                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
3679                     reverse_128(&packet[1], setup->sm_peer_csrk);
3680                     break;
3681                 default:
3682                     // Unexpected PDU
3683                     log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]);
3684                     break;
3685             }
3686             // done with key distribution?
3687             if (sm_key_distribution_all_received(sm_conn)){
3688 
3689                 sm_key_distribution_handle_all_received(sm_conn);
3690 
3691                 if (IS_RESPONDER(sm_conn->sm_role)){
3692                     if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){
3693                         sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK;
3694                     } else {
3695                         sm_conn->sm_engine_state = SM_RESPONDER_IDLE;
3696                         sm_done_for_handle(sm_conn->sm_handle);
3697                     }
3698                 } else {
3699                     if (setup->sm_use_secure_connections){
3700                         sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS;
3701                     } else {
3702                         sm_conn->sm_engine_state = SM_PH3_GET_RANDOM;
3703                     }
3704                 }
3705             }
3706             break;
3707         default:
3708             // Unexpected PDU
3709             log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state);
3710             break;
3711     }
3712 
3713     // try to send preparared packet
3714     sm_run();
3715 }
3716 
3717 // Security Manager Client API
3718 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){
3719     sm_get_oob_data = get_oob_data_callback;
3720 }
3721 
3722 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){
3723     btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler);
3724 }
3725 
3726 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){
3727     sm_accepted_stk_generation_methods = accepted_stk_generation_methods;
3728 }
3729 
3730 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){
3731 	sm_min_encryption_key_size = min_size;
3732 	sm_max_encryption_key_size = max_size;
3733 }
3734 
3735 void sm_set_authentication_requirements(uint8_t auth_req){
3736     sm_auth_req = auth_req;
3737 }
3738 
3739 void sm_set_io_capabilities(io_capability_t io_capability){
3740     sm_io_capabilities = io_capability;
3741 }
3742 
3743 #ifdef ENABLE_LE_PERIPHERAL
3744 void sm_set_request_security(int enable){
3745     sm_slave_request_security = enable;
3746 }
3747 #endif
3748 
3749 void sm_set_er(sm_key_t er){
3750     memcpy(sm_persistent_er, er, 16);
3751 }
3752 
3753 void sm_set_ir(sm_key_t ir){
3754     memcpy(sm_persistent_ir, ir, 16);
3755 }
3756 
3757 // Testing support only
3758 void sm_test_set_irk(sm_key_t irk){
3759     memcpy(sm_persistent_irk, irk, 16);
3760     sm_persistent_irk_ready = 1;
3761 }
3762 
3763 void sm_test_use_fixed_local_csrk(void){
3764     test_use_fixed_local_csrk = 1;
3765 }
3766 
3767 void sm_init(void){
3768     // set some (BTstack default) ER and IR
3769     int i;
3770     sm_key_t er;
3771     sm_key_t ir;
3772     for (i=0;i<16;i++){
3773         er[i] = 0x30 + i;
3774         ir[i] = 0x90 + i;
3775     }
3776     sm_set_er(er);
3777     sm_set_ir(ir);
3778     // defaults
3779     sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS
3780                                        | SM_STK_GENERATION_METHOD_OOB
3781                                        | SM_STK_GENERATION_METHOD_PASSKEY
3782                                        | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON;
3783 
3784     sm_max_encryption_key_size = 16;
3785     sm_min_encryption_key_size = 7;
3786 
3787 #ifdef ENABLE_CMAC_ENGINE
3788     sm_cmac_state  = CMAC_IDLE;
3789 #endif
3790     dkg_state = DKG_W4_WORKING;
3791     rau_state = RAU_W4_WORKING;
3792     sm_aes128_state = SM_AES128_IDLE;
3793     sm_address_resolution_test = -1;    // no private address to resolve yet
3794     sm_address_resolution_ah_calculation_active = 0;
3795     sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE;
3796     sm_address_resolution_general_queue = NULL;
3797 
3798     gap_random_adress_update_period = 15 * 60 * 1000L;
3799     sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
3800 
3801     test_use_fixed_local_csrk = 0;
3802 
3803     // register for HCI Events from HCI
3804     hci_event_callback_registration.callback = &sm_event_packet_handler;
3805     hci_add_event_handler(&hci_event_callback_registration);
3806 
3807     // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW
3808     l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
3809 
3810 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3811     ec_key_generation_state = EC_KEY_GENERATION_IDLE;
3812 #endif
3813 }
3814 
3815 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){
3816 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3817     memcpy(&ec_q[0],  qx, 32);
3818     memcpy(&ec_q[32], qy, 32);
3819     memcpy(ec_d, d, 32);
3820     sm_have_ec_keypair = 1;
3821     ec_key_generation_state = EC_KEY_GENERATION_DONE;
3822 #else
3823     UNUSED(qx);
3824     UNUSED(qy);
3825     UNUSED(d);
3826 #endif
3827 }
3828 
3829 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3830 static void parse_hex(uint8_t * buffer, const char * hex_string){
3831     while (*hex_string){
3832         int high_nibble = nibble_for_char(*hex_string++);
3833         int low_nibble  = nibble_for_char(*hex_string++);
3834         *buffer++       = (high_nibble << 4) | low_nibble;
3835     }
3836 }
3837 #endif
3838 
3839 void sm_test_use_fixed_ec_keypair(void){
3840 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3841     const char * ec_d_string =  "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd";
3842     const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6";
3843     const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b";
3844     parse_hex(ec_d, ec_d_string);
3845     parse_hex(&ec_q[0],  ec_qx_string);
3846     parse_hex(&ec_q[32], ec_qy_string);
3847     sm_have_ec_keypair = 1;
3848     ec_key_generation_state = EC_KEY_GENERATION_DONE;
3849 #endif
3850 }
3851 
3852 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){
3853     hci_connection_t * hci_con = hci_connection_for_handle(con_handle);
3854     if (!hci_con) return NULL;
3855     return &hci_con->sm_connection;
3856 }
3857 
3858 // @returns 0 if not encrypted, 7-16 otherwise
3859 int sm_encryption_key_size(hci_con_handle_t con_handle){
3860     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3861     if (!sm_conn) return 0;     // wrong connection
3862     if (!sm_conn->sm_connection_encrypted) return 0;
3863     return sm_conn->sm_actual_encryption_key_size;
3864 }
3865 
3866 int sm_authenticated(hci_con_handle_t con_handle){
3867     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3868     if (!sm_conn) return 0;     // wrong connection
3869     if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated
3870     return sm_conn->sm_connection_authenticated;
3871 }
3872 
3873 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){
3874     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3875     if (!sm_conn) return AUTHORIZATION_UNKNOWN;     // wrong connection
3876     if (!sm_conn->sm_connection_encrypted)               return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized
3877     if (!sm_conn->sm_connection_authenticated)           return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized
3878     return sm_conn->sm_connection_authorization_state;
3879 }
3880 
3881 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){
3882     switch (sm_conn->sm_engine_state){
3883         case SM_GENERAL_IDLE:
3884         case SM_RESPONDER_IDLE:
3885             sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST;
3886             sm_run();
3887             break;
3888         default:
3889             break;
3890     }
3891 }
3892 
3893 /**
3894  * @brief Trigger Security Request
3895  */
3896 void sm_send_security_request(hci_con_handle_t con_handle){
3897     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3898     if (!sm_conn) return;
3899     sm_send_security_request_for_connection(sm_conn);
3900 }
3901 
3902 // request pairing
3903 void sm_request_pairing(hci_con_handle_t con_handle){
3904     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3905     if (!sm_conn) return;     // wrong connection
3906 
3907     log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state);
3908     if (IS_RESPONDER(sm_conn->sm_role)){
3909         sm_send_security_request_for_connection(sm_conn);
3910     } else {
3911         // used as a trigger to start central/master/initiator security procedures
3912         uint16_t ediv;
3913         sm_key_t ltk;
3914         if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){
3915             switch (sm_conn->sm_irk_lookup_state){
3916                 case IRK_LOOKUP_FAILED:
3917                     sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3918                     break;
3919                 case IRK_LOOKUP_SUCCEEDED:
3920                         le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL);
3921                         if (!sm_is_null_key(ltk) || ediv){
3922                             log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index);
3923                             sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
3924                         } else {
3925                             sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3926                         }
3927                         break;
3928                 default:
3929                     sm_conn->sm_bonding_requested = 1;
3930                     break;
3931             }
3932         } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){
3933             sm_conn->sm_bonding_requested = 1;
3934         }
3935     }
3936     sm_run();
3937 }
3938 
3939 // called by client app on authorization request
3940 void sm_authorization_decline(hci_con_handle_t con_handle){
3941     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3942     if (!sm_conn) return;     // wrong connection
3943     sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED;
3944     sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0);
3945 }
3946 
3947 void sm_authorization_grant(hci_con_handle_t con_handle){
3948     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3949     if (!sm_conn) return;     // wrong connection
3950     sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED;
3951     sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1);
3952 }
3953 
3954 // GAP Bonding API
3955 
3956 void sm_bonding_decline(hci_con_handle_t con_handle){
3957     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3958     if (!sm_conn) return;     // wrong connection
3959     setup->sm_user_response = SM_USER_RESPONSE_DECLINE;
3960 
3961     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
3962         switch (setup->sm_stk_generation_method){
3963             case PK_RESP_INPUT:
3964             case PK_INIT_INPUT:
3965             case OK_BOTH_INPUT:
3966                 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED);
3967                 break;
3968             case NK_BOTH_INPUT:
3969                 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED);
3970                 break;
3971             case JUST_WORKS:
3972             case OOB:
3973                 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON);
3974                 break;
3975         }
3976     }
3977     sm_run();
3978 }
3979 
3980 void sm_just_works_confirm(hci_con_handle_t con_handle){
3981     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3982     if (!sm_conn) return;     // wrong connection
3983     setup->sm_user_response = SM_USER_RESPONSE_CONFIRM;
3984     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
3985         if (setup->sm_use_secure_connections){
3986             sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3987         } else {
3988             sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3989         }
3990     }
3991 
3992 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3993     if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){
3994         sm_sc_prepare_dhkey_check(sm_conn);
3995     }
3996 #endif
3997 
3998     sm_run();
3999 }
4000 
4001 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){
4002     // for now, it's the same
4003     sm_just_works_confirm(con_handle);
4004 }
4005 
4006 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){
4007     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4008     if (!sm_conn) return;     // wrong connection
4009     sm_reset_tk();
4010     big_endian_store_32(setup->sm_tk, 12, passkey);
4011     setup->sm_user_response = SM_USER_RESPONSE_PASSKEY;
4012     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
4013         sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
4014     }
4015 #ifdef ENABLE_LE_SECURE_CONNECTIONS
4016     memcpy(setup->sm_ra, setup->sm_tk, 16);
4017     memcpy(setup->sm_rb, setup->sm_tk, 16);
4018     if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){
4019         sm_sc_start_calculating_local_confirm(sm_conn);
4020     }
4021 #endif
4022     sm_run();
4023 }
4024 
4025 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){
4026     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4027     if (!sm_conn) return;     // wrong connection
4028     if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return;
4029     setup->sm_keypress_notification = action;
4030     sm_run();
4031 }
4032 
4033 /**
4034  * @brief Identify device in LE Device DB
4035  * @param handle
4036  * @returns index from le_device_db or -1 if not found/identified
4037  */
4038 int sm_le_device_index(hci_con_handle_t con_handle ){
4039     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4040     if (!sm_conn) return -1;
4041     return sm_conn->sm_le_db_index;
4042 }
4043 
4044 static int gap_random_address_type_requires_updates(void){
4045     if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0;
4046     if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0;
4047     return 1;
4048 }
4049 
4050 static uint8_t own_address_type(void){
4051     switch (gap_random_adress_type){
4052         case GAP_RANDOM_ADDRESS_TYPE_OFF:
4053             return BD_ADDR_TYPE_LE_PUBLIC;
4054         default:
4055             return BD_ADDR_TYPE_LE_RANDOM;
4056     }
4057 }
4058 
4059 // GAP LE API
4060 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){
4061     gap_random_address_update_stop();
4062     gap_random_adress_type = random_address_type;
4063     hci_le_set_own_address_type(own_address_type());
4064     if (!gap_random_address_type_requires_updates()) return;
4065     gap_random_address_update_start();
4066     gap_random_address_trigger();
4067 }
4068 
4069 gap_random_address_type_t gap_random_address_get_mode(void){
4070     return gap_random_adress_type;
4071 }
4072 
4073 void gap_random_address_set_update_period(int period_ms){
4074     gap_random_adress_update_period = period_ms;
4075     if (!gap_random_address_type_requires_updates()) return;
4076     gap_random_address_update_stop();
4077     gap_random_address_update_start();
4078 }
4079 
4080 void gap_random_address_set(bd_addr_t addr){
4081     gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC);
4082     memcpy(sm_random_address, addr, 6);
4083     if (rau_state == RAU_W4_WORKING) return;
4084     rau_state = RAU_SET_ADDRESS;
4085     sm_run();
4086 }
4087 
4088 #ifdef ENABLE_LE_PERIPHERAL
4089 /*
4090  * @brief Set Advertisement Paramters
4091  * @param adv_int_min
4092  * @param adv_int_max
4093  * @param adv_type
4094  * @param direct_address_type
4095  * @param direct_address
4096  * @param channel_map
4097  * @param filter_policy
4098  *
4099  * @note own_address_type is used from gap_random_address_set_mode
4100  */
4101 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type,
4102     uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){
4103     hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type,
4104         direct_address_typ, direct_address, channel_map, filter_policy);
4105 }
4106 #endif
4107 
4108