xref: /btstack/src/ble/sm.c (revision fcae305fb22a6740cf3bf82a590eac260422f5b3)
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 
84 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS)
85 #define ENABLE_CMAC_ENGINE
86 #endif
87 
88 //
89 // SM internal types and globals
90 //
91 
92 typedef enum {
93     DKG_W4_WORKING,
94     DKG_CALC_IRK,
95     DKG_W4_IRK,
96     DKG_CALC_DHK,
97     DKG_W4_DHK,
98     DKG_READY
99 } derived_key_generation_t;
100 
101 typedef enum {
102     RAU_W4_WORKING,
103     RAU_IDLE,
104     RAU_GET_RANDOM,
105     RAU_W4_RANDOM,
106     RAU_GET_ENC,
107     RAU_W4_ENC,
108     RAU_SET_ADDRESS,
109 } random_address_update_t;
110 
111 typedef enum {
112     CMAC_IDLE,
113     CMAC_CALC_SUBKEYS,
114     CMAC_W4_SUBKEYS,
115     CMAC_CALC_MI,
116     CMAC_W4_MI,
117     CMAC_CALC_MLAST,
118     CMAC_W4_MLAST
119 } cmac_state_t;
120 
121 typedef enum {
122     JUST_WORKS,
123     PK_RESP_INPUT,  // Initiator displays PK, responder inputs PK
124     PK_INIT_INPUT,  // Responder displays PK, initiator inputs PK
125     OK_BOTH_INPUT,  // Only input on both, both input PK
126     NK_BOTH_INPUT,  // Only numerical compparison (yes/no) on on both sides
127     OOB             // OOB available on both sides
128 } stk_generation_method_t;
129 
130 typedef enum {
131     SM_USER_RESPONSE_IDLE,
132     SM_USER_RESPONSE_PENDING,
133     SM_USER_RESPONSE_CONFIRM,
134     SM_USER_RESPONSE_PASSKEY,
135     SM_USER_RESPONSE_DECLINE
136 } sm_user_response_t;
137 
138 typedef enum {
139     SM_AES128_IDLE,
140     SM_AES128_ACTIVE
141 } sm_aes128_state_t;
142 
143 typedef enum {
144     ADDRESS_RESOLUTION_IDLE,
145     ADDRESS_RESOLUTION_GENERAL,
146     ADDRESS_RESOLUTION_FOR_CONNECTION,
147 } address_resolution_mode_t;
148 
149 typedef enum {
150     ADDRESS_RESOLUTION_SUCEEDED,
151     ADDRESS_RESOLUTION_FAILED,
152 } address_resolution_event_t;
153 
154 typedef enum {
155     EC_KEY_GENERATION_IDLE,
156     EC_KEY_GENERATION_ACTIVE,
157     EC_KEY_GENERATION_W4_KEY,
158     EC_KEY_GENERATION_DONE,
159 } ec_key_generation_state_t;
160 
161 typedef enum {
162     SM_STATE_VAR_DHKEY_NEEDED = 1 << 0,
163     SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1,
164     SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2,
165 } sm_state_var_t;
166 
167 //
168 // GLOBAL DATA
169 //
170 
171 static uint8_t test_use_fixed_local_csrk;
172 
173 // configuration
174 static uint8_t sm_accepted_stk_generation_methods;
175 static uint8_t sm_max_encryption_key_size;
176 static uint8_t sm_min_encryption_key_size;
177 static uint8_t sm_auth_req = 0;
178 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT;
179 static uint8_t sm_slave_request_security;
180 #ifdef ENABLE_LE_SECURE_CONNECTIONS
181 static uint8_t sm_have_ec_keypair;
182 #endif
183 
184 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values
185 static sm_key_t sm_persistent_er;
186 static sm_key_t sm_persistent_ir;
187 
188 // derived from sm_persistent_ir
189 static sm_key_t sm_persistent_dhk;
190 static sm_key_t sm_persistent_irk;
191 static uint8_t  sm_persistent_irk_ready = 0;    // used for testing
192 static derived_key_generation_t dkg_state;
193 
194 // derived from sm_persistent_er
195 // ..
196 
197 // random address update
198 static random_address_update_t rau_state;
199 static bd_addr_t sm_random_address;
200 
201 // CMAC Calculation: General
202 #ifdef ENABLE_CMAC_ENGINE
203 static cmac_state_t sm_cmac_state;
204 static uint16_t     sm_cmac_message_len;
205 static sm_key_t     sm_cmac_k;
206 static sm_key_t     sm_cmac_x;
207 static sm_key_t     sm_cmac_m_last;
208 static uint8_t      sm_cmac_block_current;
209 static uint8_t      sm_cmac_block_count;
210 static uint8_t      (*sm_cmac_get_byte)(uint16_t offset);
211 static void         (*sm_cmac_done_handler)(uint8_t * hash);
212 #endif
213 
214 // CMAC for ATT Signed Writes
215 #ifdef ENABLE_LE_SIGNED_WRITE
216 static uint8_t      sm_cmac_header[3];
217 static const uint8_t * sm_cmac_message;
218 static uint8_t      sm_cmac_sign_counter[4];
219 #endif
220 
221 // CMAC for Secure Connection functions
222 #ifdef ENABLE_LE_SECURE_CONNECTIONS
223 static sm_connection_t * sm_cmac_connection;
224 static uint8_t           sm_cmac_sc_buffer[80];
225 #endif
226 
227 // resolvable private address lookup / CSRK calculation
228 static int       sm_address_resolution_test;
229 static int       sm_address_resolution_ah_calculation_active;
230 static uint8_t   sm_address_resolution_addr_type;
231 static bd_addr_t sm_address_resolution_address;
232 static void *    sm_address_resolution_context;
233 static address_resolution_mode_t sm_address_resolution_mode;
234 static btstack_linked_list_t sm_address_resolution_general_queue;
235 
236 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context
237 static sm_aes128_state_t  sm_aes128_state;
238 static void *             sm_aes128_context;
239 
240 // use aes128 provided by MCU - not needed usually
241 #ifdef HAVE_AES128
242 static uint8_t                aes128_result_flipped[16];
243 static btstack_timer_source_t aes128_timer;
244 void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result);
245 #endif
246 
247 // random engine. store context (ususally sm_connection_t)
248 static void * sm_random_context;
249 
250 // to receive hci events
251 static btstack_packet_callback_registration_t hci_event_callback_registration;
252 
253 /* to dispatch sm event */
254 static btstack_linked_list_t sm_event_handlers;
255 
256 // LE Secure Connections
257 #ifdef ENABLE_LE_SECURE_CONNECTIONS
258 static ec_key_generation_state_t ec_key_generation_state;
259 static uint8_t ec_d[32];
260 static uint8_t ec_q[64];
261 #endif
262 
263 //
264 // Volume 3, Part H, Chapter 24
265 // "Security shall be initiated by the Security Manager in the device in the master role.
266 // The device in the slave role shall be the responding device."
267 // -> master := initiator, slave := responder
268 //
269 
270 // data needed for security setup
271 typedef struct sm_setup_context {
272 
273     btstack_timer_source_t sm_timeout;
274 
275     // used in all phases
276     uint8_t   sm_pairing_failed_reason;
277 
278     // user response, (Phase 1 and/or 2)
279     uint8_t   sm_user_response;
280     uint8_t   sm_keypress_notification;
281 
282     // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3
283     int       sm_key_distribution_send_set;
284     int       sm_key_distribution_received_set;
285 
286     // Phase 2 (Pairing over SMP)
287     stk_generation_method_t sm_stk_generation_method;
288     sm_key_t  sm_tk;
289     uint8_t   sm_use_secure_connections;
290 
291     sm_key_t  sm_c1_t3_value;   // c1 calculation
292     sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1
293     sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1
294     sm_key_t  sm_local_random;
295     sm_key_t  sm_local_confirm;
296     sm_key_t  sm_peer_random;
297     sm_key_t  sm_peer_confirm;
298     uint8_t   sm_m_addr_type;   // address and type can be removed
299     uint8_t   sm_s_addr_type;   //  ''
300     bd_addr_t sm_m_address;     //  ''
301     bd_addr_t sm_s_address;     //  ''
302     sm_key_t  sm_ltk;
303 
304     uint8_t   sm_state_vars;
305 #ifdef ENABLE_LE_SECURE_CONNECTIONS
306     uint8_t   sm_peer_q[64];    // also stores random for EC key generation during init
307     sm_key_t  sm_peer_nonce;    // might be combined with sm_peer_random
308     sm_key_t  sm_local_nonce;   // might be combined with sm_local_random
309     sm_key_t  sm_dhkey;
310     sm_key_t  sm_peer_dhkey_check;
311     sm_key_t  sm_local_dhkey_check;
312     sm_key_t  sm_ra;
313     sm_key_t  sm_rb;
314     sm_key_t  sm_t;             // used for f5 and h6
315     sm_key_t  sm_mackey;
316     uint8_t   sm_passkey_bit;   // also stores number of generated random bytes for EC key generation
317 #endif
318 
319     // Phase 3
320 
321     // key distribution, we generate
322     uint16_t  sm_local_y;
323     uint16_t  sm_local_div;
324     uint16_t  sm_local_ediv;
325     uint8_t   sm_local_rand[8];
326     sm_key_t  sm_local_ltk;
327     sm_key_t  sm_local_csrk;
328     sm_key_t  sm_local_irk;
329     // sm_local_address/addr_type not needed
330 
331     // key distribution, received from peer
332     uint16_t  sm_peer_y;
333     uint16_t  sm_peer_div;
334     uint16_t  sm_peer_ediv;
335     uint8_t   sm_peer_rand[8];
336     sm_key_t  sm_peer_ltk;
337     sm_key_t  sm_peer_irk;
338     sm_key_t  sm_peer_csrk;
339     uint8_t   sm_peer_addr_type;
340     bd_addr_t sm_peer_address;
341 
342 } sm_setup_context_t;
343 
344 //
345 static sm_setup_context_t the_setup;
346 static sm_setup_context_t * setup = &the_setup;
347 
348 // active connection - the one for which the_setup is used for
349 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
350 
351 // @returns 1 if oob data is available
352 // stores oob data in provided 16 byte buffer if not null
353 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL;
354 
355 // horizontal: initiator capabilities
356 // vertial:    responder capabilities
357 static const stk_generation_method_t stk_generation_method [5] [5] = {
358     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
359     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
360     { PK_RESP_INPUT,   PK_RESP_INPUT,    OK_BOTH_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
361     { JUST_WORKS,      JUST_WORKS,       JUST_WORKS,      JUST_WORKS,    JUST_WORKS    },
362     { PK_RESP_INPUT,   PK_RESP_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
363 };
364 
365 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations
366 #ifdef ENABLE_LE_SECURE_CONNECTIONS
367 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = {
368     { JUST_WORKS,      JUST_WORKS,       PK_INIT_INPUT,   JUST_WORKS,    PK_INIT_INPUT },
369     { JUST_WORKS,      NK_BOTH_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    NK_BOTH_INPUT },
370     { PK_RESP_INPUT,   PK_RESP_INPUT,    OK_BOTH_INPUT,   JUST_WORKS,    PK_RESP_INPUT },
371     { JUST_WORKS,      JUST_WORKS,       JUST_WORKS,      JUST_WORKS,    JUST_WORKS    },
372     { PK_RESP_INPUT,   NK_BOTH_INPUT,    PK_INIT_INPUT,   JUST_WORKS,    NK_BOTH_INPUT },
373 };
374 #endif
375 
376 static void sm_run(void);
377 static void sm_done_for_handle(hci_con_handle_t con_handle);
378 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle);
379 static inline int sm_calc_actual_encryption_key_size(int other);
380 static int sm_validate_stk_generation_method(void);
381 static void sm_handle_encryption_result(uint8_t * data);
382 
383 static void log_info_hex16(const char * name, uint16_t value){
384     log_info("%-6s 0x%04x", name, value);
385 }
386 
387 // @returns 1 if all bytes are 0
388 static int sm_is_null(uint8_t * data, int size){
389     int i;
390     for (i=0; i < size ; i++){
391         if (data[i]) return 0;
392     }
393     return 1;
394 }
395 
396 static int sm_is_null_random(uint8_t random[8]){
397     return sm_is_null(random, 8);
398 }
399 
400 static int sm_is_null_key(uint8_t * key){
401     return sm_is_null(key, 16);
402 }
403 
404 // Key utils
405 static void sm_reset_tk(void){
406     int i;
407     for (i=0;i<16;i++){
408         setup->sm_tk[i] = 0;
409     }
410 }
411 
412 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0
413 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0.""
414 static void sm_truncate_key(sm_key_t key, int max_encryption_size){
415     int i;
416     for (i = max_encryption_size ; i < 16 ; i++){
417         key[15-i] = 0;
418     }
419 }
420 
421 // SMP Timeout implementation
422 
423 // Upon transmission of the Pairing Request command or reception of the Pairing Request command,
424 // the Security Manager Timer shall be reset and started.
425 //
426 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission.
427 //
428 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed,
429 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP
430 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been
431 // established.
432 
433 static void sm_timeout_handler(btstack_timer_source_t * timer){
434     log_info("SM timeout");
435     sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer);
436     sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT;
437     sm_done_for_handle(sm_conn->sm_handle);
438 
439     // trigger handling of next ready connection
440     sm_run();
441 }
442 static void sm_timeout_start(sm_connection_t * sm_conn){
443     btstack_run_loop_remove_timer(&setup->sm_timeout);
444     btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn);
445     btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler);
446     btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout
447     btstack_run_loop_add_timer(&setup->sm_timeout);
448 }
449 static void sm_timeout_stop(void){
450     btstack_run_loop_remove_timer(&setup->sm_timeout);
451 }
452 static void sm_timeout_reset(sm_connection_t * sm_conn){
453     sm_timeout_stop();
454     sm_timeout_start(sm_conn);
455 }
456 
457 // end of sm timeout
458 
459 // GAP Random Address updates
460 static gap_random_address_type_t gap_random_adress_type;
461 static btstack_timer_source_t gap_random_address_update_timer;
462 static uint32_t gap_random_adress_update_period;
463 
464 static void gap_random_address_trigger(void){
465     if (rau_state != RAU_IDLE) return;
466     log_info("gap_random_address_trigger");
467     rau_state = RAU_GET_RANDOM;
468     sm_run();
469 }
470 
471 static void gap_random_address_update_handler(btstack_timer_source_t * timer){
472     UNUSED(timer);
473 
474     log_info("GAP Random Address Update due");
475     btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period);
476     btstack_run_loop_add_timer(&gap_random_address_update_timer);
477     gap_random_address_trigger();
478 }
479 
480 static void gap_random_address_update_start(void){
481     btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler);
482     btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period);
483     btstack_run_loop_add_timer(&gap_random_address_update_timer);
484 }
485 
486 static void gap_random_address_update_stop(void){
487     btstack_run_loop_remove_timer(&gap_random_address_update_timer);
488 }
489 
490 
491 static void sm_random_start(void * context){
492     sm_random_context = context;
493     hci_send_cmd(&hci_le_rand);
494 }
495 
496 #ifdef HAVE_AES128
497 static void aes128_completed(btstack_timer_source_t * ts){
498     UNUSED(ts);
499     sm_handle_encryption_result(&aes128_result_flipped[0]);
500     sm_run();
501 }
502 #endif
503 
504 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1
505 // context is made availabe to aes128 result handler by this
506 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){
507     sm_aes128_state = SM_AES128_ACTIVE;
508     sm_aes128_context = context;
509 
510 #ifdef HAVE_AES128
511     // calc result directly
512     sm_key_t result;
513     btstack_aes128_calc(key, plaintext, result);
514 
515     // log
516     log_info_key("key", key);
517     log_info_key("txt", plaintext);
518     log_info_key("res", result);
519 
520     // flip
521     reverse_128(&result[0], &aes128_result_flipped[0]);
522 
523     // deliver via timer
524     btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed);
525     btstack_run_loop_set_timer(&aes128_timer, 0);    // no delay
526     btstack_run_loop_add_timer(&aes128_timer);
527 #else
528     sm_key_t key_flipped, plaintext_flipped;
529     reverse_128(key, key_flipped);
530     reverse_128(plaintext, plaintext_flipped);
531     hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped);
532 #endif
533 }
534 
535 // ah(k,r) helper
536 // r = padding || r
537 // r - 24 bit value
538 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){
539     // r'= padding || r
540     memset(r_prime, 0, 16);
541     memcpy(&r_prime[13], r, 3);
542 }
543 
544 // d1 helper
545 // d' = padding || r || d
546 // d,r - 16 bit values
547 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){
548     // d'= padding || r || d
549     memset(d1_prime, 0, 16);
550     big_endian_store_16(d1_prime, 12, r);
551     big_endian_store_16(d1_prime, 14, d);
552 }
553 
554 // dm helper
555 // r’ = padding || r
556 // r - 64 bit value
557 static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){
558     memset(r_prime, 0, 16);
559     memcpy(&r_prime[8], r, 8);
560 }
561 
562 // calculate arguments for first AES128 operation in C1 function
563 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){
564 
565     // p1 = pres || preq || rat’ || iat’
566     // "The octet of iat’ becomes the least significant octet of p1 and the most signifi-
567     // cant octet of pres becomes the most significant octet of p1.
568     // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq
569     // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then
570     // p1 is 0x05000800000302070710000001010001."
571 
572     sm_key_t p1;
573     reverse_56(pres, &p1[0]);
574     reverse_56(preq, &p1[7]);
575     p1[14] = rat;
576     p1[15] = iat;
577     log_info_key("p1", p1);
578     log_info_key("r", r);
579 
580     // t1 = r xor p1
581     int i;
582     for (i=0;i<16;i++){
583         t1[i] = r[i] ^ p1[i];
584     }
585     log_info_key("t1", t1);
586 }
587 
588 // calculate arguments for second AES128 operation in C1 function
589 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){
590      // p2 = padding || ia || ra
591     // "The least significant octet of ra becomes the least significant octet of p2 and
592     // the most significant octet of padding becomes the most significant octet of p2.
593     // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is
594     // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6.
595 
596     sm_key_t p2;
597     memset(p2, 0, 16);
598     memcpy(&p2[4],  ia, 6);
599     memcpy(&p2[10], ra, 6);
600     log_info_key("p2", p2);
601 
602     // c1 = e(k, t2_xor_p2)
603     int i;
604     for (i=0;i<16;i++){
605         t3[i] = t2[i] ^ p2[i];
606     }
607     log_info_key("t3", t3);
608 }
609 
610 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){
611     log_info_key("r1", r1);
612     log_info_key("r2", r2);
613     memcpy(&r_prime[8], &r2[8], 8);
614     memcpy(&r_prime[0], &r1[8], 8);
615 }
616 
617 #ifdef ENABLE_LE_SECURE_CONNECTIONS
618 // Software implementations of crypto toolbox for LE Secure Connection
619 // TODO: replace with code to use AES Engine of HCI Controller
620 typedef uint8_t sm_key24_t[3];
621 typedef uint8_t sm_key56_t[7];
622 typedef uint8_t sm_key256_t[32];
623 
624 #if 0
625 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){
626     uint32_t rk[RKLENGTH(KEYBITS)];
627     int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS);
628     rijndaelEncrypt(rk, nrounds, plaintext, cyphertext);
629 }
630 
631 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){
632     memcpy(k1, k0, 16);
633     sm_shift_left_by_one_bit_inplace(16, k1);
634     if (k0[0] & 0x80){
635         k1[15] ^= 0x87;
636     }
637     memcpy(k2, k1, 16);
638     sm_shift_left_by_one_bit_inplace(16, k2);
639     if (k1[0] & 0x80){
640         k2[15] ^= 0x87;
641     }
642 }
643 
644 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){
645     sm_key_t k0, k1, k2, zero;
646     memset(zero, 0, 16);
647 
648     aes128_calc_cyphertext(key, zero, k0);
649     calc_subkeys(k0, k1, k2);
650 
651     int cmac_block_count = (cmac_message_len + 15) / 16;
652 
653     // step 3: ..
654     if (cmac_block_count==0){
655         cmac_block_count = 1;
656     }
657 
658     // step 4: set m_last
659     sm_key_t cmac_m_last;
660     int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0;
661     int i;
662     if (sm_cmac_last_block_complete){
663         for (i=0;i<16;i++){
664             cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i];
665         }
666     } else {
667         int valid_octets_in_last_block = cmac_message_len & 0x0f;
668         for (i=0;i<16;i++){
669             if (i < valid_octets_in_last_block){
670                 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i];
671                 continue;
672             }
673             if (i == valid_octets_in_last_block){
674                 cmac_m_last[i] = 0x80 ^ k2[i];
675                 continue;
676             }
677             cmac_m_last[i] = k2[i];
678         }
679     }
680 
681     // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count);
682     // LOG_KEY(cmac_m_last);
683 
684     // Step 5
685     sm_key_t cmac_x;
686     memset(cmac_x, 0, 16);
687 
688     // Step 6
689     sm_key_t sm_cmac_y;
690     for (int block = 0 ; block < cmac_block_count-1 ; block++){
691         for (i=0;i<16;i++){
692             sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i];
693         }
694         aes128_calc_cyphertext(key, sm_cmac_y, cmac_x);
695     }
696     for (i=0;i<16;i++){
697         sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i];
698     }
699 
700     // Step 7
701     aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac);
702 }
703 #endif
704 #endif
705 
706 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){
707     event[0] = type;
708     event[1] = event_size - 2;
709     little_endian_store_16(event, 2, con_handle);
710     event[4] = addr_type;
711     reverse_bd_addr(address, &event[5]);
712 }
713 
714 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){
715     UNUSED(channel);
716 
717     // log event
718     hci_dump_packet(packet_type, 1, packet, size);
719     // dispatch to all event handlers
720     btstack_linked_list_iterator_t it;
721     btstack_linked_list_iterator_init(&it, &sm_event_handlers);
722     while (btstack_linked_list_iterator_has_next(&it)){
723         btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it);
724         entry->callback(packet_type, 0, packet, size);
725     }
726 }
727 
728 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){
729     uint8_t event[11];
730     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
731     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
732 }
733 
734 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){
735     uint8_t event[15];
736     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
737     little_endian_store_32(event, 11, passkey);
738     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
739 }
740 
741 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){
742     // fetch addr and addr type from db
743     bd_addr_t identity_address;
744     int identity_address_type;
745     le_device_db_info(index, &identity_address_type, identity_address, NULL);
746 
747     uint8_t event[19];
748     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
749     event[11] = identity_address_type;
750     reverse_bd_addr(identity_address, &event[12]);
751     event[18] = index;
752     sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event));
753 }
754 
755 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){
756 
757     uint8_t event[18];
758     sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address);
759     event[11] = result;
760     sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event));
761 }
762 
763 // decide on stk generation based on
764 // - pairing request
765 // - io capabilities
766 // - OOB data availability
767 static void sm_setup_tk(void){
768 
769     // default: just works
770     setup->sm_stk_generation_method = JUST_WORKS;
771 
772 #ifdef ENABLE_LE_SECURE_CONNECTIONS
773     setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq)
774                                        & sm_pairing_packet_get_auth_req(setup->sm_s_pres)
775                                        & SM_AUTHREQ_SECURE_CONNECTION ) != 0;
776     memset(setup->sm_ra, 0, 16);
777     memset(setup->sm_rb, 0, 16);
778 #else
779     setup->sm_use_secure_connections = 0;
780 #endif
781 
782     // If both devices have not set the MITM option in the Authentication Requirements
783     // Flags, then the IO capabilities shall be ignored and the Just Works association
784     // model shall be used.
785     if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0)
786     &&  ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){
787         log_info("SM: MITM not required by both -> JUST WORKS");
788         return;
789     }
790 
791     // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient
792 
793     // If both devices have out of band authentication data, then the Authentication
794     // Requirements Flags shall be ignored when selecting the pairing method and the
795     // Out of Band pairing method shall be used.
796     if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq)
797     &&  sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){
798         log_info("SM: have OOB data");
799         log_info_key("OOB", setup->sm_tk);
800         setup->sm_stk_generation_method = OOB;
801         return;
802     }
803 
804     // Reset TK as it has been setup in sm_init_setup
805     sm_reset_tk();
806 
807     // Also use just works if unknown io capabilites
808     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)){
809         return;
810     }
811 
812     // Otherwise the IO capabilities of the devices shall be used to determine the
813     // pairing method as defined in Table 2.4.
814     // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array
815     const stk_generation_method_t (*generation_method)[5] = stk_generation_method;
816 
817 #ifdef ENABLE_LE_SECURE_CONNECTIONS
818     // table not define by default
819     if (setup->sm_use_secure_connections){
820         generation_method = stk_generation_method_with_secure_connection;
821     }
822 #endif
823     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)];
824 
825     log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u",
826         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);
827 }
828 
829 static int sm_key_distribution_flags_for_set(uint8_t key_set){
830     int flags = 0;
831     if (key_set & SM_KEYDIST_ENC_KEY){
832         flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
833         flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
834     }
835     if (key_set & SM_KEYDIST_ID_KEY){
836         flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
837         flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
838     }
839     if (key_set & SM_KEYDIST_SIGN){
840         flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
841     }
842     return flags;
843 }
844 
845 static void sm_setup_key_distribution(uint8_t key_set){
846     setup->sm_key_distribution_received_set = 0;
847     setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set);
848 }
849 
850 // CSRK Key Lookup
851 
852 
853 static int sm_address_resolution_idle(void){
854     return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE;
855 }
856 
857 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){
858     memcpy(sm_address_resolution_address, addr, 6);
859     sm_address_resolution_addr_type = addr_type;
860     sm_address_resolution_test = 0;
861     sm_address_resolution_mode = mode;
862     sm_address_resolution_context = context;
863     sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr);
864 }
865 
866 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){
867     // check if already in list
868     btstack_linked_list_iterator_t it;
869     sm_lookup_entry_t * entry;
870     btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue);
871     while(btstack_linked_list_iterator_has_next(&it)){
872         entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it);
873         if (entry->address_type != address_type) continue;
874         if (memcmp(entry->address, address, 6))  continue;
875         // already in list
876         return BTSTACK_BUSY;
877     }
878     entry = btstack_memory_sm_lookup_entry_get();
879     if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED;
880     entry->address_type = (bd_addr_type_t) address_type;
881     memcpy(entry->address, address, 6);
882     btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry);
883     sm_run();
884     return 0;
885 }
886 
887 // 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
888 static inline void sm_next_responding_state(sm_connection_t * sm_conn){
889     sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1);
890 }
891 static inline void dkg_next_state(void){
892     dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1);
893 }
894 static inline void rau_next_state(void){
895     rau_state = (random_address_update_t) (((int)rau_state) + 1);
896 }
897 
898 // CMAC calculation using AES Engine
899 #ifdef ENABLE_CMAC_ENGINE
900 
901 static inline void sm_cmac_next_state(void){
902     sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1);
903 }
904 
905 static int sm_cmac_last_block_complete(void){
906     if (sm_cmac_message_len == 0) return 0;
907     return (sm_cmac_message_len & 0x0f) == 0;
908 }
909 
910 int sm_cmac_ready(void){
911     return sm_cmac_state == CMAC_IDLE;
912 }
913 
914 // generic cmac calculation
915 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])){
916     // Generalized CMAC
917     memcpy(sm_cmac_k, key, 16);
918     memset(sm_cmac_x, 0, 16);
919     sm_cmac_block_current = 0;
920     sm_cmac_message_len  = message_len;
921     sm_cmac_done_handler = done_callback;
922     sm_cmac_get_byte     = get_byte_callback;
923 
924     // step 2: n := ceil(len/const_Bsize);
925     sm_cmac_block_count = (sm_cmac_message_len + 15) / 16;
926 
927     // step 3: ..
928     if (sm_cmac_block_count==0){
929         sm_cmac_block_count = 1;
930     }
931     log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count);
932 
933     // first, we need to compute l for k1, k2, and m_last
934     sm_cmac_state = CMAC_CALC_SUBKEYS;
935 
936     // let's go
937     sm_run();
938 }
939 #endif
940 
941 // cmac for ATT Message signing
942 #ifdef ENABLE_LE_SIGNED_WRITE
943 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){
944     if (offset >= sm_cmac_message_len) {
945         log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len);
946         return 0;
947     }
948 
949     offset = sm_cmac_message_len - 1 - offset;
950 
951     // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4]
952     if (offset < 3){
953         return sm_cmac_header[offset];
954     }
955     int actual_message_len_incl_header = sm_cmac_message_len - 4;
956     if (offset <  actual_message_len_incl_header){
957         return sm_cmac_message[offset - 3];
958     }
959     return sm_cmac_sign_counter[offset - actual_message_len_incl_header];
960 }
961 
962 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)){
963     // ATT Message Signing
964     sm_cmac_header[0] = opcode;
965     little_endian_store_16(sm_cmac_header, 1, con_handle);
966     little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter);
967     uint16_t total_message_len = 3 + message_len + 4;  // incl. virtually prepended att opcode, handle and appended sign_counter in LE
968     sm_cmac_message = message;
969     sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler);
970 }
971 #endif
972 
973 #ifdef ENABLE_CMAC_ENGINE
974 static void sm_cmac_handle_aes_engine_ready(void){
975     switch (sm_cmac_state){
976         case CMAC_CALC_SUBKEYS: {
977             sm_key_t const_zero;
978             memset(const_zero, 0, 16);
979             sm_cmac_next_state();
980             sm_aes128_start(sm_cmac_k, const_zero, NULL);
981             break;
982         }
983         case CMAC_CALC_MI: {
984             int j;
985             sm_key_t y;
986             for (j=0;j<16;j++){
987                 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j);
988             }
989             sm_cmac_block_current++;
990             sm_cmac_next_state();
991             sm_aes128_start(sm_cmac_k, y, NULL);
992             break;
993         }
994         case CMAC_CALC_MLAST: {
995             int i;
996             sm_key_t y;
997             for (i=0;i<16;i++){
998                 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i];
999             }
1000             log_info_key("Y", y);
1001             sm_cmac_block_current++;
1002             sm_cmac_next_state();
1003             sm_aes128_start(sm_cmac_k, y, NULL);
1004             break;
1005         }
1006         default:
1007             log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state);
1008             break;
1009     }
1010 }
1011 
1012 // CMAC Implementation using AES128 engine
1013 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){
1014     int i;
1015     int carry = 0;
1016     for (i=len-1; i >= 0 ; i--){
1017         int new_carry = data[i] >> 7;
1018         data[i] = data[i] << 1 | carry;
1019         carry = new_carry;
1020     }
1021 }
1022 
1023 static void sm_cmac_handle_encryption_result(sm_key_t data){
1024     switch (sm_cmac_state){
1025         case CMAC_W4_SUBKEYS: {
1026             sm_key_t k1;
1027             memcpy(k1, data, 16);
1028             sm_shift_left_by_one_bit_inplace(16, k1);
1029             if (data[0] & 0x80){
1030                 k1[15] ^= 0x87;
1031             }
1032             sm_key_t k2;
1033             memcpy(k2, k1, 16);
1034             sm_shift_left_by_one_bit_inplace(16, k2);
1035             if (k1[0] & 0x80){
1036                 k2[15] ^= 0x87;
1037             }
1038 
1039             log_info_key("k", sm_cmac_k);
1040             log_info_key("k1", k1);
1041             log_info_key("k2", k2);
1042 
1043             // step 4: set m_last
1044             int i;
1045             if (sm_cmac_last_block_complete()){
1046                 for (i=0;i<16;i++){
1047                     sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i];
1048                 }
1049             } else {
1050                 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f;
1051                 for (i=0;i<16;i++){
1052                     if (i < valid_octets_in_last_block){
1053                         sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i];
1054                         continue;
1055                     }
1056                     if (i == valid_octets_in_last_block){
1057                         sm_cmac_m_last[i] = 0x80 ^ k2[i];
1058                         continue;
1059                     }
1060                     sm_cmac_m_last[i] = k2[i];
1061                 }
1062             }
1063 
1064             // next
1065             sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST;
1066             break;
1067         }
1068         case CMAC_W4_MI:
1069             memcpy(sm_cmac_x, data, 16);
1070             sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST;
1071             break;
1072         case CMAC_W4_MLAST:
1073             // done
1074             log_info("Setting CMAC Engine to IDLE");
1075             sm_cmac_state = CMAC_IDLE;
1076             log_info_key("CMAC", data);
1077             sm_cmac_done_handler(data);
1078             break;
1079         default:
1080             log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state);
1081             break;
1082     }
1083 }
1084 #endif
1085 
1086 static void sm_trigger_user_response(sm_connection_t * sm_conn){
1087     // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input
1088     setup->sm_user_response = SM_USER_RESPONSE_IDLE;
1089     switch (setup->sm_stk_generation_method){
1090         case PK_RESP_INPUT:
1091             if (IS_RESPONDER(sm_conn->sm_role)){
1092                 setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1093                 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1094             } else {
1095                 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));
1096             }
1097             break;
1098         case PK_INIT_INPUT:
1099             if (IS_RESPONDER(sm_conn->sm_role)){
1100                 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));
1101             } else {
1102                 setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1103                 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1104             }
1105             break;
1106         case OK_BOTH_INPUT:
1107             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1108             sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1109             break;
1110         case NK_BOTH_INPUT:
1111             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1112             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));
1113             break;
1114         case JUST_WORKS:
1115             setup->sm_user_response = SM_USER_RESPONSE_PENDING;
1116             sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
1117             break;
1118         case OOB:
1119             // client already provided OOB data, let's skip notification.
1120             break;
1121     }
1122 }
1123 
1124 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){
1125     int recv_flags;
1126     if (IS_RESPONDER(sm_conn->sm_role)){
1127         // slave / responder
1128         recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres));
1129     } else {
1130         // master / initiator
1131         recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres));
1132     }
1133     log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags);
1134     return recv_flags == setup->sm_key_distribution_received_set;
1135 }
1136 
1137 static void sm_done_for_handle(hci_con_handle_t con_handle){
1138     if (sm_active_connection_handle == con_handle){
1139         sm_timeout_stop();
1140         sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
1141         log_info("sm: connection 0x%x released setup context", con_handle);
1142     }
1143 }
1144 
1145 static int sm_key_distribution_flags_for_auth_req(void){
1146     int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN;
1147     if (sm_auth_req & SM_AUTHREQ_BONDING){
1148         // encryption information only if bonding requested
1149         flags |= SM_KEYDIST_ENC_KEY;
1150     }
1151     return flags;
1152 }
1153 
1154 static void sm_reset_setup(void){
1155     // fill in sm setup
1156     setup->sm_state_vars = 0;
1157     setup->sm_keypress_notification = 0xff;
1158     sm_reset_tk();
1159 }
1160 
1161 static void sm_init_setup(sm_connection_t * sm_conn){
1162 
1163     // fill in sm setup
1164     setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type;
1165     memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6);
1166 
1167     // query client for OOB data
1168     int have_oob_data = 0;
1169     if (sm_get_oob_data) {
1170         have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk);
1171     }
1172 
1173     sm_pairing_packet_t * local_packet;
1174     if (IS_RESPONDER(sm_conn->sm_role)){
1175         // slave
1176         local_packet = &setup->sm_s_pres;
1177         gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address);
1178         setup->sm_m_addr_type = sm_conn->sm_peer_addr_type;
1179         memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6);
1180     } else {
1181         // master
1182         local_packet = &setup->sm_m_preq;
1183         gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address);
1184         setup->sm_s_addr_type = sm_conn->sm_peer_addr_type;
1185         memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6);
1186 
1187         int key_distribution_flags = sm_key_distribution_flags_for_auth_req();
1188         sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags);
1189         sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags);
1190     }
1191 
1192     uint8_t auth_req = sm_auth_req;
1193     sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities);
1194     sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data);
1195     sm_pairing_packet_set_auth_req(*local_packet, auth_req);
1196     sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size);
1197 }
1198 
1199 static int sm_stk_generation_init(sm_connection_t * sm_conn){
1200 
1201     sm_pairing_packet_t * remote_packet;
1202     int                   remote_key_request;
1203     if (IS_RESPONDER(sm_conn->sm_role)){
1204         // slave / responder
1205         remote_packet      = &setup->sm_m_preq;
1206         remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq);
1207     } else {
1208         // master / initiator
1209         remote_packet      = &setup->sm_s_pres;
1210         remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres);
1211     }
1212 
1213     // check key size
1214     sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet));
1215     if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE;
1216 
1217     // decide on STK generation method
1218     sm_setup_tk();
1219     log_info("SMP: generation method %u", setup->sm_stk_generation_method);
1220 
1221     // check if STK generation method is acceptable by client
1222     if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS;
1223 
1224     // identical to responder
1225     sm_setup_key_distribution(remote_key_request);
1226 
1227     // JUST WORKS doens't provide authentication
1228     sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1;
1229 
1230     return 0;
1231 }
1232 
1233 static void sm_address_resolution_handle_event(address_resolution_event_t event){
1234 
1235     // cache and reset context
1236     int matched_device_id = sm_address_resolution_test;
1237     address_resolution_mode_t mode = sm_address_resolution_mode;
1238     void * context = sm_address_resolution_context;
1239 
1240     // reset context
1241     sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE;
1242     sm_address_resolution_context = NULL;
1243     sm_address_resolution_test = -1;
1244     hci_con_handle_t con_handle = 0;
1245 
1246     sm_connection_t * sm_connection;
1247 #ifdef ENABLE_LE_CENTRAL
1248     sm_key_t ltk;
1249 #endif
1250     switch (mode){
1251         case ADDRESS_RESOLUTION_GENERAL:
1252             break;
1253         case ADDRESS_RESOLUTION_FOR_CONNECTION:
1254             sm_connection = (sm_connection_t *) context;
1255             con_handle = sm_connection->sm_handle;
1256             switch (event){
1257                 case ADDRESS_RESOLUTION_SUCEEDED:
1258                     sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED;
1259                     sm_connection->sm_le_db_index = matched_device_id;
1260                     log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index);
1261 #ifdef ENABLE_LE_CENTRAL
1262                     if (sm_connection->sm_role) break;
1263                     if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break;
1264                     sm_connection->sm_security_request_received = 0;
1265                     sm_connection->sm_bonding_requested = 0;
1266                     le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL);
1267                     if (!sm_is_null_key(ltk)){
1268                         sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
1269                     } else {
1270                         sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
1271                     }
1272 #endif
1273                     break;
1274                 case ADDRESS_RESOLUTION_FAILED:
1275                     sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED;
1276 #ifdef ENABLE_LE_CENTRAL
1277                     if (sm_connection->sm_role) break;
1278                     if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break;
1279                     sm_connection->sm_security_request_received = 0;
1280                     sm_connection->sm_bonding_requested = 0;
1281                     sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
1282 #endif
1283                     break;
1284             }
1285             break;
1286         default:
1287             break;
1288     }
1289 
1290     switch (event){
1291         case ADDRESS_RESOLUTION_SUCEEDED:
1292             sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id);
1293             break;
1294         case ADDRESS_RESOLUTION_FAILED:
1295             sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address);
1296             break;
1297     }
1298 }
1299 
1300 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){
1301 
1302     int le_db_index = -1;
1303 
1304     // lookup device based on IRK
1305     if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){
1306         int i;
1307         for (i=0; i < le_device_db_count(); i++){
1308             sm_key_t irk;
1309             bd_addr_t address;
1310             int address_type;
1311             le_device_db_info(i, &address_type, address, irk);
1312             if (memcmp(irk, setup->sm_peer_irk, 16) == 0){
1313                 log_info("sm: device found for IRK, updating");
1314                 le_db_index = i;
1315                 break;
1316             }
1317         }
1318     }
1319 
1320     // if not found, lookup via public address if possible
1321     log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address));
1322     if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){
1323         int i;
1324         for (i=0; i < le_device_db_count(); i++){
1325             bd_addr_t address;
1326             int address_type;
1327             le_device_db_info(i, &address_type, address, NULL);
1328             log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address));
1329             if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){
1330                 log_info("sm: device found for public address, updating");
1331                 le_db_index = i;
1332                 break;
1333             }
1334         }
1335     }
1336 
1337     // if not found, add to db
1338     if (le_db_index < 0) {
1339         le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk);
1340     }
1341 
1342     sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index);
1343 
1344     if (le_db_index >= 0){
1345 
1346 #ifdef ENABLE_LE_SIGNED_WRITE
1347         // store local CSRK
1348         if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
1349             log_info("sm: store local CSRK");
1350             le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk);
1351             le_device_db_local_counter_set(le_db_index, 0);
1352         }
1353 
1354         // store remote CSRK
1355         if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
1356             log_info("sm: store remote CSRK");
1357             le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk);
1358             le_device_db_remote_counter_set(le_db_index, 0);
1359         }
1360 #endif
1361         // store encryption information for secure connections: LTK generated by ECDH
1362         if (setup->sm_use_secure_connections){
1363             log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated);
1364             uint8_t zero_rand[8];
1365             memset(zero_rand, 0, 8);
1366             le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size,
1367                 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED);
1368         }
1369 
1370         // store encryption information for legacy pairing: peer LTK, EDIV, RAND
1371         else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION)
1372                && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){
1373             log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated);
1374             le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk,
1375                 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED);
1376 
1377         }
1378     }
1379 
1380     // keep le_db_index
1381     sm_conn->sm_le_db_index = le_db_index;
1382 }
1383 
1384 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){
1385     setup->sm_pairing_failed_reason = reason;
1386     sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
1387 }
1388 
1389 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){
1390     sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON);
1391 }
1392 
1393 #ifdef ENABLE_LE_SECURE_CONNECTIONS
1394 
1395 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn);
1396 static int sm_passkey_used(stk_generation_method_t method);
1397 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method);
1398 
1399 static void sm_log_ec_keypair(void){
1400     log_info("Elliptic curve: X");
1401     log_info_hexdump(&ec_q[0],32);
1402     log_info("Elliptic curve: Y");
1403     log_info_hexdump(&ec_q[32],32);
1404 }
1405 
1406 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){
1407     if (sm_passkey_used(setup->sm_stk_generation_method)){
1408         sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A;
1409     } else {
1410         sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION;
1411     }
1412 }
1413 
1414 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){
1415     if (IS_RESPONDER(sm_conn->sm_role)){
1416         // Responder
1417         sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM;
1418     } else {
1419         // Initiator role
1420         switch (setup->sm_stk_generation_method){
1421             case JUST_WORKS:
1422                 sm_sc_prepare_dhkey_check(sm_conn);
1423                 break;
1424 
1425             case NK_BOTH_INPUT:
1426                 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2;
1427                 break;
1428             case PK_INIT_INPUT:
1429             case PK_RESP_INPUT:
1430             case OK_BOTH_INPUT:
1431                 if (setup->sm_passkey_bit < 20) {
1432                     sm_sc_start_calculating_local_confirm(sm_conn);
1433                 } else {
1434                     sm_sc_prepare_dhkey_check(sm_conn);
1435                 }
1436                 break;
1437             case OOB:
1438                 // TODO: implement SC OOB
1439                 break;
1440         }
1441     }
1442 }
1443 
1444 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){
1445     return sm_cmac_sc_buffer[offset];
1446 }
1447 
1448 static void sm_sc_cmac_done(uint8_t * hash){
1449     log_info("sm_sc_cmac_done: ");
1450     log_info_hexdump(hash, 16);
1451 
1452     sm_connection_t * sm_conn = sm_cmac_connection;
1453     sm_cmac_connection = NULL;
1454 #ifdef ENABLE_CLASSIC
1455     link_key_type_t link_key_type;
1456 #endif
1457 
1458     switch (sm_conn->sm_engine_state){
1459         case SM_SC_W4_CMAC_FOR_CONFIRMATION:
1460             memcpy(setup->sm_local_confirm, hash, 16);
1461             sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION;
1462             break;
1463         case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION:
1464             // check
1465             if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){
1466                 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED);
1467                 break;
1468             }
1469             sm_sc_state_after_receiving_random(sm_conn);
1470             break;
1471         case SM_SC_W4_CALCULATE_G2: {
1472             uint32_t vab = big_endian_read_32(hash, 12) % 1000000;
1473             big_endian_store_32(setup->sm_tk, 12, vab);
1474             sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
1475             sm_trigger_user_response(sm_conn);
1476             break;
1477         }
1478         case SM_SC_W4_CALCULATE_F5_SALT:
1479             memcpy(setup->sm_t, hash, 16);
1480             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY;
1481             break;
1482         case SM_SC_W4_CALCULATE_F5_MACKEY:
1483             memcpy(setup->sm_mackey, hash, 16);
1484             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK;
1485             break;
1486         case SM_SC_W4_CALCULATE_F5_LTK:
1487             // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk
1488             // Errata Service Release to the Bluetooth Specification: ESR09
1489             //   E6405 – Cross transport key derivation from a key of size less than 128 bits
1490             //   Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked."
1491             memcpy(setup->sm_ltk, hash, 16);
1492             memcpy(setup->sm_local_ltk, hash, 16);
1493             sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size);
1494             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK;
1495             break;
1496         case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK:
1497             memcpy(setup->sm_local_dhkey_check, hash, 16);
1498             if (IS_RESPONDER(sm_conn->sm_role)){
1499                 // responder
1500                 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){
1501                     sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
1502                 } else {
1503                     sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND;
1504                 }
1505             } else {
1506                 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND;
1507             }
1508             break;
1509         case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK:
1510             if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){
1511                 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED);
1512                 break;
1513             }
1514             if (IS_RESPONDER(sm_conn->sm_role)){
1515                 // responder
1516                 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND;
1517             } else {
1518                 // initiator
1519                 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION;
1520             }
1521             break;
1522         case SM_SC_W4_CALCULATE_H6_ILK:
1523             memcpy(setup->sm_t, hash, 16);
1524             sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY;
1525             break;
1526         case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY:
1527 #ifdef ENABLE_CLASSIC
1528             reverse_128(hash, setup->sm_t);
1529             link_key_type = sm_conn->sm_connection_authenticated ?
1530                 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256;
1531             log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type);
1532             if (IS_RESPONDER(sm_conn->sm_role)){
1533                 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type);
1534             } else {
1535                 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type);
1536             }
1537 #endif
1538             if (IS_RESPONDER(sm_conn->sm_role)){
1539                 sm_conn->sm_engine_state = SM_RESPONDER_IDLE;
1540             } else {
1541                 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED;
1542             }
1543             sm_done_for_handle(sm_conn->sm_handle);
1544             break;
1545         default:
1546             log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state);
1547             break;
1548     }
1549     sm_run();
1550 }
1551 
1552 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){
1553     const uint16_t message_len = 65;
1554     sm_cmac_connection = sm_conn;
1555     memcpy(sm_cmac_sc_buffer, u, 32);
1556     memcpy(sm_cmac_sc_buffer+32, v, 32);
1557     sm_cmac_sc_buffer[64] = z;
1558     log_info("f4 key");
1559     log_info_hexdump(x, 16);
1560     log_info("f4 message");
1561     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1562     sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1563 }
1564 
1565 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE};
1566 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 };
1567 static const uint8_t f5_length[] = { 0x01, 0x00};
1568 
1569 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1570 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){
1571     memset(dhkey, 0, 32);
1572 #if uECC_SUPPORTS_secp256r1
1573     // standard version
1574     uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1());
1575 #else
1576     // static version
1577     uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey);
1578 #endif
1579     log_info("dhkey");
1580     log_info_hexdump(dhkey, 32);
1581 }
1582 #endif
1583 
1584 static void f5_calculate_salt(sm_connection_t * sm_conn){
1585     // calculate salt for f5
1586     const uint16_t message_len = 32;
1587     sm_cmac_connection = sm_conn;
1588     memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len);
1589     sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1590 }
1591 
1592 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){
1593     const uint16_t message_len = 53;
1594     sm_cmac_connection = sm_conn;
1595 
1596     // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey
1597     sm_cmac_sc_buffer[0] = 0;
1598     memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4);
1599     memcpy(sm_cmac_sc_buffer+05, n1, 16);
1600     memcpy(sm_cmac_sc_buffer+21, n2, 16);
1601     memcpy(sm_cmac_sc_buffer+37, a1, 7);
1602     memcpy(sm_cmac_sc_buffer+44, a2, 7);
1603     memcpy(sm_cmac_sc_buffer+51, f5_length, 2);
1604     log_info("f5 key");
1605     log_info_hexdump(t, 16);
1606     log_info("f5 message for MacKey");
1607     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1608     sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1609 }
1610 
1611 static void f5_calculate_mackey(sm_connection_t * sm_conn){
1612     sm_key56_t bd_addr_master, bd_addr_slave;
1613     bd_addr_master[0] =  setup->sm_m_addr_type;
1614     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1615     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1616     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1617     if (IS_RESPONDER(sm_conn->sm_role)){
1618         // responder
1619         f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave);
1620     } else {
1621         // initiator
1622         f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave);
1623     }
1624 }
1625 
1626 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused
1627 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){
1628     const uint16_t message_len = 53;
1629     sm_cmac_connection = sm_conn;
1630     sm_cmac_sc_buffer[0] = 1;
1631     // 1..52 setup before
1632     log_info("f5 key");
1633     log_info_hexdump(t, 16);
1634     log_info("f5 message for LTK");
1635     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1636     sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1637 }
1638 
1639 static void f5_calculate_ltk(sm_connection_t * sm_conn){
1640     f5_ltk(sm_conn, setup->sm_t);
1641 }
1642 
1643 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){
1644     const uint16_t message_len = 65;
1645     sm_cmac_connection = sm_conn;
1646     memcpy(sm_cmac_sc_buffer, n1, 16);
1647     memcpy(sm_cmac_sc_buffer+16, n2, 16);
1648     memcpy(sm_cmac_sc_buffer+32, r, 16);
1649     memcpy(sm_cmac_sc_buffer+48, io_cap, 3);
1650     memcpy(sm_cmac_sc_buffer+51, a1, 7);
1651     memcpy(sm_cmac_sc_buffer+58, a2, 7);
1652     log_info("f6 key");
1653     log_info_hexdump(w, 16);
1654     log_info("f6 message");
1655     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1656     sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1657 }
1658 
1659 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32
1660 // - U is 256 bits
1661 // - V is 256 bits
1662 // - X is 128 bits
1663 // - Y is 128 bits
1664 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){
1665     const uint16_t message_len = 80;
1666     sm_cmac_connection = sm_conn;
1667     memcpy(sm_cmac_sc_buffer, u, 32);
1668     memcpy(sm_cmac_sc_buffer+32, v, 32);
1669     memcpy(sm_cmac_sc_buffer+64, y, 16);
1670     log_info("g2 key");
1671     log_info_hexdump(x, 16);
1672     log_info("g2 message");
1673     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1674     sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1675 }
1676 
1677 static void g2_calculate(sm_connection_t * sm_conn) {
1678     // calc Va if numeric comparison
1679     if (IS_RESPONDER(sm_conn->sm_role)){
1680         // responder
1681         g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);;
1682     } else {
1683         // initiator
1684         g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce);
1685     }
1686 }
1687 
1688 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){
1689     uint8_t z = 0;
1690     if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){
1691         // some form of passkey
1692         uint32_t pk = big_endian_read_32(setup->sm_tk, 12);
1693         z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1);
1694         setup->sm_passkey_bit++;
1695     }
1696     f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z);
1697 }
1698 
1699 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){
1700     uint8_t z = 0;
1701     if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){
1702         // some form of passkey
1703         uint32_t pk = big_endian_read_32(setup->sm_tk, 12);
1704         // sm_passkey_bit was increased before sending confirm value
1705         z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1);
1706     }
1707     f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z);
1708 }
1709 
1710 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){
1711 
1712 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1713     // calculate DHKEY
1714     sm_sc_calculate_dhkey(setup->sm_dhkey);
1715     setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED;
1716 #endif
1717 
1718     if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){
1719         sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT;
1720         return;
1721     } else {
1722         sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY;
1723     }
1724 
1725 }
1726 
1727 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){
1728     // calculate DHKCheck
1729     sm_key56_t bd_addr_master, bd_addr_slave;
1730     bd_addr_master[0] =  setup->sm_m_addr_type;
1731     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1732     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1733     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1734     uint8_t iocap_a[3];
1735     iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq);
1736     iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq);
1737     iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq);
1738     uint8_t iocap_b[3];
1739     iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres);
1740     iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres);
1741     iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres);
1742     if (IS_RESPONDER(sm_conn->sm_role)){
1743         // responder
1744         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);
1745     } else {
1746         // initiator
1747         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);
1748     }
1749 }
1750 
1751 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){
1752     // validate E = f6()
1753     sm_key56_t bd_addr_master, bd_addr_slave;
1754     bd_addr_master[0] =  setup->sm_m_addr_type;
1755     bd_addr_slave[0]  =  setup->sm_s_addr_type;
1756     memcpy(&bd_addr_master[1], setup->sm_m_address, 6);
1757     memcpy(&bd_addr_slave[1],  setup->sm_s_address, 6);
1758 
1759     uint8_t iocap_a[3];
1760     iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq);
1761     iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq);
1762     iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq);
1763     uint8_t iocap_b[3];
1764     iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres);
1765     iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres);
1766     iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres);
1767     if (IS_RESPONDER(sm_conn->sm_role)){
1768         // responder
1769         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);
1770     } else {
1771         // initiator
1772         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);
1773     }
1774 }
1775 
1776 
1777 //
1778 // Link Key Conversion Function h6
1779 //
1780 // h6(W, keyID) = AES-CMACW(keyID)
1781 // - W is 128 bits
1782 // - keyID is 32 bits
1783 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){
1784     const uint16_t message_len = 4;
1785     sm_cmac_connection = sm_conn;
1786     big_endian_store_32(sm_cmac_sc_buffer, 0, key_id);
1787     log_info("h6 key");
1788     log_info_hexdump(w, 16);
1789     log_info("h6 message");
1790     log_info_hexdump(sm_cmac_sc_buffer, message_len);
1791     sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done);
1792 }
1793 
1794 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated)
1795 // Errata Service Release to the Bluetooth Specification: ESR09
1796 //   E6405 – Cross transport key derivation from a key of size less than 128 bits
1797 //   "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked."
1798 static void h6_calculate_ilk(sm_connection_t * sm_conn){
1799     h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031);    // "tmp1"
1800 }
1801 
1802 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){
1803     h6_engine(sm_conn, setup->sm_t, 0x6c656272);    // "lebr"
1804 }
1805 
1806 #endif
1807 
1808 // key management legacy connections:
1809 // - potentially two different LTKs based on direction. each device stores LTK provided by peer
1810 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect)
1811 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder
1812 // - responder  reconnects: responder uses LTK receveived from master
1813 
1814 // key management secure connections:
1815 // - both devices store same LTK from ECDH key exchange.
1816 
1817 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL)
1818 static void sm_load_security_info(sm_connection_t * sm_connection){
1819     int encryption_key_size;
1820     int authenticated;
1821     int authorized;
1822 
1823     // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled
1824     le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk,
1825                                 &encryption_key_size, &authenticated, &authorized);
1826     log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized);
1827     sm_connection->sm_actual_encryption_key_size = encryption_key_size;
1828     sm_connection->sm_connection_authenticated = authenticated;
1829     sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN;
1830 }
1831 #endif
1832 
1833 #ifdef ENABLE_LE_PERIPHERAL
1834 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){
1835     memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8);
1836     setup->sm_local_ediv = sm_connection->sm_local_ediv;
1837     // re-establish used key encryption size
1838     // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand
1839     sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1;
1840     // no db for authenticated flag hack: flag is stored in bit 4 of LSB
1841     sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4;
1842     log_info("sm: received ltk request with key size %u, authenticated %u",
1843             sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated);
1844     sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC;
1845 }
1846 #endif
1847 
1848 static void sm_run(void){
1849 
1850     btstack_linked_list_iterator_t it;
1851 
1852     // assert that stack has already bootet
1853     if (hci_get_state() != HCI_STATE_WORKING) return;
1854 
1855     // assert that we can send at least commands
1856     if (!hci_can_send_command_packet_now()) return;
1857 
1858     //
1859     // non-connection related behaviour
1860     //
1861 
1862     // distributed key generation
1863     switch (dkg_state){
1864         case DKG_CALC_IRK:
1865             // already busy?
1866             if (sm_aes128_state == SM_AES128_IDLE) {
1867                 // IRK = d1(IR, 1, 0)
1868                 sm_key_t d1_prime;
1869                 sm_d1_d_prime(1, 0, d1_prime);  // plaintext
1870                 dkg_next_state();
1871                 sm_aes128_start(sm_persistent_ir, d1_prime, NULL);
1872                 return;
1873             }
1874             break;
1875         case DKG_CALC_DHK:
1876             // already busy?
1877             if (sm_aes128_state == SM_AES128_IDLE) {
1878                 // DHK = d1(IR, 3, 0)
1879                 sm_key_t d1_prime;
1880                 sm_d1_d_prime(3, 0, d1_prime);  // plaintext
1881                 dkg_next_state();
1882                 sm_aes128_start(sm_persistent_ir, d1_prime, NULL);
1883                 return;
1884             }
1885             break;
1886         default:
1887             break;
1888     }
1889 
1890 #ifdef ENABLE_LE_SECURE_CONNECTIONS
1891     if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){
1892 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
1893         sm_random_start(NULL);
1894 #else
1895         ec_key_generation_state = EC_KEY_GENERATION_W4_KEY;
1896         hci_send_cmd(&hci_le_read_local_p256_public_key);
1897 #endif
1898         return;
1899     }
1900 #endif
1901 
1902     // random address updates
1903     switch (rau_state){
1904         case RAU_GET_RANDOM:
1905             rau_next_state();
1906             sm_random_start(NULL);
1907             return;
1908         case RAU_GET_ENC:
1909             // already busy?
1910             if (sm_aes128_state == SM_AES128_IDLE) {
1911                 sm_key_t r_prime;
1912                 sm_ah_r_prime(sm_random_address, r_prime);
1913                 rau_next_state();
1914                 sm_aes128_start(sm_persistent_irk, r_prime, NULL);
1915                 return;
1916             }
1917             break;
1918         case RAU_SET_ADDRESS:
1919             log_info("New random address: %s", bd_addr_to_str(sm_random_address));
1920             rau_state = RAU_IDLE;
1921             hci_send_cmd(&hci_le_set_random_address, sm_random_address);
1922             return;
1923         default:
1924             break;
1925     }
1926 
1927 #ifdef ENABLE_CMAC_ENGINE
1928     // CMAC
1929     switch (sm_cmac_state){
1930         case CMAC_CALC_SUBKEYS:
1931         case CMAC_CALC_MI:
1932         case CMAC_CALC_MLAST:
1933             // already busy?
1934             if (sm_aes128_state == SM_AES128_ACTIVE) break;
1935             sm_cmac_handle_aes_engine_ready();
1936             return;
1937         default:
1938             break;
1939     }
1940 #endif
1941 
1942     // CSRK Lookup
1943     // -- if csrk lookup ready, find connection that require csrk lookup
1944     if (sm_address_resolution_idle()){
1945         hci_connections_get_iterator(&it);
1946         while(btstack_linked_list_iterator_has_next(&it)){
1947             hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
1948             sm_connection_t  * sm_connection  = &hci_connection->sm_connection;
1949             if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){
1950                 // and start lookup
1951                 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);
1952                 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED;
1953                 break;
1954             }
1955         }
1956     }
1957 
1958     // -- if csrk lookup ready, resolved addresses for received addresses
1959     if (sm_address_resolution_idle()) {
1960         if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){
1961             sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue;
1962             btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry);
1963             sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL);
1964             btstack_memory_sm_lookup_entry_free(entry);
1965         }
1966     }
1967 
1968     // -- Continue with CSRK device lookup by public or resolvable private address
1969     if (!sm_address_resolution_idle()){
1970         log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count());
1971         while (sm_address_resolution_test < le_device_db_count()){
1972             int addr_type;
1973             bd_addr_t addr;
1974             sm_key_t irk;
1975             le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk);
1976             log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr));
1977 
1978             if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){
1979                 log_info("LE Device Lookup: found CSRK by { addr_type, address} ");
1980                 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED);
1981                 break;
1982             }
1983 
1984             if (sm_address_resolution_addr_type == 0){
1985                 sm_address_resolution_test++;
1986                 continue;
1987             }
1988 
1989             if (sm_aes128_state == SM_AES128_ACTIVE) break;
1990 
1991             log_info("LE Device Lookup: calculate AH");
1992             log_info_key("IRK", irk);
1993 
1994             sm_key_t r_prime;
1995             sm_ah_r_prime(sm_address_resolution_address, r_prime);
1996             sm_address_resolution_ah_calculation_active = 1;
1997             sm_aes128_start(irk, r_prime, sm_address_resolution_context);   // keep context
1998             return;
1999         }
2000 
2001         if (sm_address_resolution_test >= le_device_db_count()){
2002             log_info("LE Device Lookup: not found");
2003             sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED);
2004         }
2005     }
2006 
2007     // handle basic actions that don't requires the full context
2008     hci_connections_get_iterator(&it);
2009     while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){
2010         hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
2011         sm_connection_t  * sm_connection = &hci_connection->sm_connection;
2012         switch(sm_connection->sm_engine_state){
2013             // responder side
2014             case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY:
2015                 sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2016                 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2017                 return;
2018 
2019 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2020             case SM_SC_RECEIVED_LTK_REQUEST:
2021                 switch (sm_connection->sm_irk_lookup_state){
2022                     case IRK_LOOKUP_FAILED:
2023                         log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)");
2024                         sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2025                         hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2026                         return;
2027                     default:
2028                         break;
2029                 }
2030                 break;
2031 #endif
2032             default:
2033                 break;
2034         }
2035     }
2036 
2037     //
2038     // active connection handling
2039     // -- use loop to handle next connection if lock on setup context is released
2040 
2041     while (1) {
2042 
2043         // Find connections that requires setup context and make active if no other is locked
2044         hci_connections_get_iterator(&it);
2045         while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){
2046             hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
2047             sm_connection_t  * sm_connection = &hci_connection->sm_connection;
2048             // - if no connection locked and we're ready/waiting for setup context, fetch it and start
2049             int done = 1;
2050             int err;
2051             UNUSED(err);
2052             switch (sm_connection->sm_engine_state) {
2053 #ifdef ENABLE_LE_PERIPHERAL
2054                 case SM_RESPONDER_SEND_SECURITY_REQUEST:
2055                     // send packet if possible,
2056                     if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){
2057                         const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING};
2058                         sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST;
2059                         l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2060                     } else {
2061                         l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
2062                     }
2063                     // don't lock sxetup context yet
2064                     done = 0;
2065                     break;
2066                 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED:
2067                     sm_reset_setup();
2068                     sm_init_setup(sm_connection);
2069                     // recover pairing request
2070                     memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t));
2071                     err = sm_stk_generation_init(sm_connection);
2072                     if (err){
2073                         setup->sm_pairing_failed_reason = err;
2074                         sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
2075                         break;
2076                     }
2077                     sm_timeout_start(sm_connection);
2078                     // generate random number first, if we need to show passkey
2079                     if (setup->sm_stk_generation_method == PK_INIT_INPUT){
2080                         sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK;
2081                         break;
2082                     }
2083                     sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE;
2084                     break;
2085                 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST:
2086                     sm_reset_setup();
2087                     sm_start_calculating_ltk_from_ediv_and_rand(sm_connection);
2088                     break;
2089 #endif
2090 #ifdef ENABLE_LE_CENTRAL
2091                 case SM_INITIATOR_PH0_HAS_LTK:
2092                     sm_reset_setup();
2093                     sm_load_security_info(sm_connection);
2094                     sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION;
2095                     break;
2096                 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST:
2097                     sm_reset_setup();
2098                     sm_init_setup(sm_connection);
2099                     sm_timeout_start(sm_connection);
2100                     sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST;
2101                     break;
2102 #endif
2103 
2104 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2105                 case SM_SC_RECEIVED_LTK_REQUEST:
2106                     switch (sm_connection->sm_irk_lookup_state){
2107                         case IRK_LOOKUP_SUCCEEDED:
2108                             // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null
2109                             // start using context by loading security info
2110                             sm_reset_setup();
2111                             sm_load_security_info(sm_connection);
2112                             if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){
2113                                 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16);
2114                                 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY;
2115                                 break;
2116                             }
2117                             log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)");
2118                             sm_connection->sm_engine_state = SM_RESPONDER_IDLE;
2119                             hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle);
2120                             // don't lock setup context yet
2121                             return;
2122                         default:
2123                             // just wait until IRK lookup is completed
2124                             // don't lock setup context yet
2125                             done = 0;
2126                             break;
2127                     }
2128                     break;
2129 #endif
2130                 default:
2131                     done = 0;
2132                     break;
2133             }
2134             if (done){
2135                 sm_active_connection_handle = sm_connection->sm_handle;
2136                 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);
2137             }
2138         }
2139 
2140         //
2141         // active connection handling
2142         //
2143 
2144         if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return;
2145 
2146         sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle);
2147         if (!connection) {
2148             log_info("no connection for handle 0x%04x", sm_active_connection_handle);
2149             return;
2150         }
2151 
2152 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || !defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
2153         if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_NEEDED){
2154             setup->sm_state_vars &= ~SM_STATE_VAR_DHKEY_NEEDED;
2155             hci_send_cmd(&hci_le_generate_dhkey, &setup->sm_peer_q[0], &setup->sm_peer_q[32]);
2156             return;
2157         }
2158 #endif
2159 
2160         // assert that we could send a SM PDU - not needed for all of the following
2161         if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) {
2162             log_info("cannot send now, requesting can send now event");
2163             l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
2164             return;
2165         }
2166 
2167         // send keypress notifications
2168         if (setup->sm_keypress_notification != 0xff){
2169             uint8_t buffer[2];
2170             buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION;
2171             buffer[1] = setup->sm_keypress_notification;
2172             setup->sm_keypress_notification = 0xff;
2173             l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2174             return;
2175         }
2176 
2177         sm_key_t plaintext;
2178         int key_distribution_flags;
2179         UNUSED(key_distribution_flags);
2180 
2181         log_info("sm_run: state %u", connection->sm_engine_state);
2182 
2183         switch (connection->sm_engine_state){
2184 
2185             // general
2186             case SM_GENERAL_SEND_PAIRING_FAILED: {
2187                 uint8_t buffer[2];
2188                 buffer[0] = SM_CODE_PAIRING_FAILED;
2189                 buffer[1] = setup->sm_pairing_failed_reason;
2190                 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED;
2191                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2192                 sm_done_for_handle(connection->sm_handle);
2193                 break;
2194             }
2195 
2196             // responding state
2197 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2198             case SM_SC_W2_GET_RANDOM_A:
2199                 sm_random_start(connection);
2200                 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A;
2201                 break;
2202             case SM_SC_W2_GET_RANDOM_B:
2203                 sm_random_start(connection);
2204                 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B;
2205                 break;
2206             case SM_SC_W2_CMAC_FOR_CONFIRMATION:
2207                 if (!sm_cmac_ready()) break;
2208                 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION;
2209                 sm_sc_calculate_local_confirm(connection);
2210                 break;
2211             case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION:
2212                 if (!sm_cmac_ready()) break;
2213                 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION;
2214                 sm_sc_calculate_remote_confirm(connection);
2215                 break;
2216             case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK:
2217                 if (!sm_cmac_ready()) break;
2218                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK;
2219                 sm_sc_calculate_f6_for_dhkey_check(connection);
2220                 break;
2221             case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK:
2222                 if (!sm_cmac_ready()) break;
2223                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
2224                 sm_sc_calculate_f6_to_verify_dhkey_check(connection);
2225                 break;
2226             case SM_SC_W2_CALCULATE_F5_SALT:
2227                 if (!sm_cmac_ready()) break;
2228                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT;
2229                 f5_calculate_salt(connection);
2230                 break;
2231             case SM_SC_W2_CALCULATE_F5_MACKEY:
2232                 if (!sm_cmac_ready()) break;
2233                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY;
2234                 f5_calculate_mackey(connection);
2235                 break;
2236             case SM_SC_W2_CALCULATE_F5_LTK:
2237                 if (!sm_cmac_ready()) break;
2238                 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK;
2239                 f5_calculate_ltk(connection);
2240                 break;
2241             case SM_SC_W2_CALCULATE_G2:
2242                 if (!sm_cmac_ready()) break;
2243                 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2;
2244                 g2_calculate(connection);
2245                 break;
2246             case SM_SC_W2_CALCULATE_H6_ILK:
2247                 if (!sm_cmac_ready()) break;
2248                 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK;
2249                 h6_calculate_ilk(connection);
2250                 break;
2251             case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY:
2252                 if (!sm_cmac_ready()) break;
2253                 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY;
2254                 h6_calculate_br_edr_link_key(connection);
2255                 break;
2256 #endif
2257 
2258 #ifdef ENABLE_LE_CENTRAL
2259             // initiator side
2260             case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: {
2261                 sm_key_t peer_ltk_flipped;
2262                 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped);
2263                 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED;
2264                 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv);
2265                 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0);
2266                 uint32_t rand_low  = big_endian_read_32(setup->sm_peer_rand, 4);
2267                 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped);
2268                 return;
2269             }
2270 
2271             case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST:
2272                 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST);
2273                 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE;
2274                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t));
2275                 sm_timeout_reset(connection);
2276                 break;
2277 #endif
2278 
2279 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2280 
2281             case SM_SC_SEND_PUBLIC_KEY_COMMAND: {
2282                 uint8_t buffer[65];
2283                 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY;
2284                 //
2285                 reverse_256(&ec_q[0],  &buffer[1]);
2286                 reverse_256(&ec_q[32], &buffer[33]);
2287 
2288                 // stk generation method
2289                 // passkey entry: notify app to show passkey or to request passkey
2290                 switch (setup->sm_stk_generation_method){
2291                     case JUST_WORKS:
2292                     case NK_BOTH_INPUT:
2293                         if (IS_RESPONDER(connection->sm_role)){
2294                             // responder
2295                             sm_sc_start_calculating_local_confirm(connection);
2296                         } else {
2297                             // initiator
2298                             connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2299                         }
2300                         break;
2301                     case PK_INIT_INPUT:
2302                     case PK_RESP_INPUT:
2303                     case OK_BOTH_INPUT:
2304                         // use random TK for display
2305                         memcpy(setup->sm_ra, setup->sm_tk, 16);
2306                         memcpy(setup->sm_rb, setup->sm_tk, 16);
2307                         setup->sm_passkey_bit = 0;
2308 
2309                         if (IS_RESPONDER(connection->sm_role)){
2310                             // responder
2311                             connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2312                         } else {
2313                             // initiator
2314                             connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2315                         }
2316                         sm_trigger_user_response(connection);
2317                         break;
2318                     case OOB:
2319                         // TODO: implement SC OOB
2320                         break;
2321                 }
2322 
2323                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2324                 sm_timeout_reset(connection);
2325                 break;
2326             }
2327             case SM_SC_SEND_CONFIRMATION: {
2328                 uint8_t buffer[17];
2329                 buffer[0] = SM_CODE_PAIRING_CONFIRM;
2330                 reverse_128(setup->sm_local_confirm, &buffer[1]);
2331                 if (IS_RESPONDER(connection->sm_role)){
2332                     connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2333                 } else {
2334                     connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2335                 }
2336                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2337                 sm_timeout_reset(connection);
2338                 break;
2339             }
2340             case SM_SC_SEND_PAIRING_RANDOM: {
2341                 uint8_t buffer[17];
2342                 buffer[0] = SM_CODE_PAIRING_RANDOM;
2343                 reverse_128(setup->sm_local_nonce, &buffer[1]);
2344                 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){
2345                     if (IS_RESPONDER(connection->sm_role)){
2346                         // responder
2347                         connection->sm_engine_state = SM_SC_W4_CONFIRMATION;
2348                     } else {
2349                         // initiator
2350                         connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2351                     }
2352                 } else {
2353                     if (IS_RESPONDER(connection->sm_role)){
2354                         // responder
2355                         if (setup->sm_stk_generation_method == NK_BOTH_INPUT){
2356                             connection->sm_engine_state = SM_SC_W2_CALCULATE_G2;
2357                         } else {
2358                             sm_sc_prepare_dhkey_check(connection);
2359                         }
2360                     } else {
2361                         // initiator
2362                         connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM;
2363                     }
2364                 }
2365                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2366                 sm_timeout_reset(connection);
2367                 break;
2368             }
2369             case SM_SC_SEND_DHKEY_CHECK_COMMAND: {
2370                 uint8_t buffer[17];
2371                 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK;
2372                 reverse_128(setup->sm_local_dhkey_check, &buffer[1]);
2373 
2374                 if (IS_RESPONDER(connection->sm_role)){
2375                     connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC;
2376                 } else {
2377                     connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND;
2378                 }
2379 
2380                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2381                 sm_timeout_reset(connection);
2382                 break;
2383             }
2384 
2385 #endif
2386 
2387 #ifdef ENABLE_LE_PERIPHERAL
2388             case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE:
2389                 // echo initiator for now
2390                 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE);
2391                 key_distribution_flags = sm_key_distribution_flags_for_auth_req();
2392 
2393                 if (setup->sm_use_secure_connections){
2394                     connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND;
2395                     // skip LTK/EDIV for SC
2396                     log_info("sm: dropping encryption information flag");
2397                     key_distribution_flags &= ~SM_KEYDIST_ENC_KEY;
2398                 } else {
2399                     connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM;
2400                 }
2401 
2402                 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);
2403                 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);
2404                 // update key distribution after ENC was dropped
2405                 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres));
2406 
2407                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t));
2408                 sm_timeout_reset(connection);
2409                 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged
2410                 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){
2411                     sm_trigger_user_response(connection);
2412                 }
2413                 return;
2414 #endif
2415 
2416             case SM_PH2_SEND_PAIRING_RANDOM: {
2417                 uint8_t buffer[17];
2418                 buffer[0] = SM_CODE_PAIRING_RANDOM;
2419                 reverse_128(setup->sm_local_random, &buffer[1]);
2420                 if (IS_RESPONDER(connection->sm_role)){
2421                     connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST;
2422                 } else {
2423                     connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM;
2424                 }
2425                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2426                 sm_timeout_reset(connection);
2427                 break;
2428             }
2429 
2430             case SM_PH2_GET_RANDOM_TK:
2431             case SM_PH2_C1_GET_RANDOM_A:
2432             case SM_PH2_C1_GET_RANDOM_B:
2433             case SM_PH3_GET_RANDOM:
2434             case SM_PH3_GET_DIV:
2435                 sm_next_responding_state(connection);
2436                 sm_random_start(connection);
2437                 return;
2438 
2439             case SM_PH2_C1_GET_ENC_B:
2440             case SM_PH2_C1_GET_ENC_D:
2441                 // already busy?
2442                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2443                 sm_next_responding_state(connection);
2444                 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection);
2445                 return;
2446 
2447             case SM_PH3_LTK_GET_ENC:
2448             case SM_RESPONDER_PH4_LTK_GET_ENC:
2449                 // already busy?
2450                 if (sm_aes128_state == SM_AES128_IDLE) {
2451                     sm_key_t d_prime;
2452                     sm_d1_d_prime(setup->sm_local_div, 0, d_prime);
2453                     sm_next_responding_state(connection);
2454                     sm_aes128_start(sm_persistent_er, d_prime, connection);
2455                     return;
2456                 }
2457                 break;
2458 
2459             case SM_PH3_CSRK_GET_ENC:
2460                 // already busy?
2461                 if (sm_aes128_state == SM_AES128_IDLE) {
2462                     sm_key_t d_prime;
2463                     sm_d1_d_prime(setup->sm_local_div, 1, d_prime);
2464                     sm_next_responding_state(connection);
2465                     sm_aes128_start(sm_persistent_er, d_prime, connection);
2466                     return;
2467                 }
2468                 break;
2469 
2470             case SM_PH2_C1_GET_ENC_C:
2471                 // already busy?
2472                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2473                 // calculate m_confirm using aes128 engine - step 1
2474                 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);
2475                 sm_next_responding_state(connection);
2476                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2477                 break;
2478             case SM_PH2_C1_GET_ENC_A:
2479                 // already busy?
2480                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2481                 // calculate confirm using aes128 engine - step 1
2482                 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);
2483                 sm_next_responding_state(connection);
2484                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2485                 break;
2486             case SM_PH2_CALC_STK:
2487                 // already busy?
2488                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2489                 // calculate STK
2490                 if (IS_RESPONDER(connection->sm_role)){
2491                     sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext);
2492                 } else {
2493                     sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext);
2494                 }
2495                 sm_next_responding_state(connection);
2496                 sm_aes128_start(setup->sm_tk, plaintext, connection);
2497                 break;
2498             case SM_PH3_Y_GET_ENC:
2499                 // already busy?
2500                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2501                 // PH3B2 - calculate Y from      - enc
2502                 // Y = dm(DHK, Rand)
2503                 sm_dm_r_prime(setup->sm_local_rand, plaintext);
2504                 sm_next_responding_state(connection);
2505                 sm_aes128_start(sm_persistent_dhk, plaintext, connection);
2506                 return;
2507             case SM_PH2_C1_SEND_PAIRING_CONFIRM: {
2508                 uint8_t buffer[17];
2509                 buffer[0] = SM_CODE_PAIRING_CONFIRM;
2510                 reverse_128(setup->sm_local_confirm, &buffer[1]);
2511                 if (IS_RESPONDER(connection->sm_role)){
2512                     connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM;
2513                 } else {
2514                     connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM;
2515                 }
2516                 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2517                 sm_timeout_reset(connection);
2518                 return;
2519             }
2520 #ifdef ENABLE_LE_PERIPHERAL
2521             case SM_RESPONDER_PH2_SEND_LTK_REPLY: {
2522                 sm_key_t stk_flipped;
2523                 reverse_128(setup->sm_ltk, stk_flipped);
2524                 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED;
2525                 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped);
2526                 return;
2527             }
2528             case SM_RESPONDER_PH4_SEND_LTK_REPLY: {
2529                 sm_key_t ltk_flipped;
2530                 reverse_128(setup->sm_ltk, ltk_flipped);
2531                 connection->sm_engine_state = SM_RESPONDER_IDLE;
2532                 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped);
2533                 return;
2534             }
2535             case SM_RESPONDER_PH4_Y_GET_ENC:
2536                 // already busy?
2537                 if (sm_aes128_state == SM_AES128_ACTIVE) break;
2538                 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv);
2539                 // Y = dm(DHK, Rand)
2540                 sm_dm_r_prime(setup->sm_local_rand, plaintext);
2541                 sm_next_responding_state(connection);
2542                 sm_aes128_start(sm_persistent_dhk, plaintext, connection);
2543                 return;
2544 #endif
2545 #ifdef ENABLE_LE_CENTRAL
2546             case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: {
2547                 sm_key_t stk_flipped;
2548                 reverse_128(setup->sm_ltk, stk_flipped);
2549                 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED;
2550                 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped);
2551                 return;
2552             }
2553 #endif
2554 
2555             case SM_PH3_DISTRIBUTE_KEYS:
2556                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){
2557                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
2558                     uint8_t buffer[17];
2559                     buffer[0] = SM_CODE_ENCRYPTION_INFORMATION;
2560                     reverse_128(setup->sm_ltk, &buffer[1]);
2561                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2562                     sm_timeout_reset(connection);
2563                     return;
2564                 }
2565                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){
2566                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
2567                     uint8_t buffer[11];
2568                     buffer[0] = SM_CODE_MASTER_IDENTIFICATION;
2569                     little_endian_store_16(buffer, 1, setup->sm_local_ediv);
2570                     reverse_64(setup->sm_local_rand, &buffer[3]);
2571                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2572                     sm_timeout_reset(connection);
2573                     return;
2574                 }
2575                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_IDENTITY_INFORMATION){
2576                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
2577                     uint8_t buffer[17];
2578                     buffer[0] = SM_CODE_IDENTITY_INFORMATION;
2579                     reverse_128(sm_persistent_irk, &buffer[1]);
2580                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2581                     sm_timeout_reset(connection);
2582                     return;
2583                 }
2584                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){
2585                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
2586                     bd_addr_t local_address;
2587                     uint8_t buffer[8];
2588                     buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION;
2589                     switch (gap_random_address_get_mode()){
2590                         case GAP_RANDOM_ADDRESS_TYPE_OFF:
2591                         case GAP_RANDOM_ADDRESS_TYPE_STATIC:
2592                             // public or static random
2593                             gap_le_get_own_address(&buffer[1], local_address);
2594                             break;
2595                         case GAP_RANDOM_ADDRESS_NON_RESOLVABLE:
2596                         case GAP_RANDOM_ADDRESS_RESOLVABLE:
2597                             // fallback to public
2598                             gap_local_bd_addr(local_address);
2599                             buffer[1] = 0;
2600                             break;
2601                     }
2602                     reverse_bd_addr(local_address, &buffer[2]);
2603                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2604                     sm_timeout_reset(connection);
2605                     return;
2606                 }
2607                 if (setup->sm_key_distribution_send_set &   SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){
2608                     setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
2609 
2610                     // hack to reproduce test runs
2611                     if (test_use_fixed_local_csrk){
2612                         memset(setup->sm_local_csrk, 0xcc, 16);
2613                     }
2614 
2615                     uint8_t buffer[17];
2616                     buffer[0] = SM_CODE_SIGNING_INFORMATION;
2617                     reverse_128(setup->sm_local_csrk, &buffer[1]);
2618                     l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer));
2619                     sm_timeout_reset(connection);
2620                     return;
2621                 }
2622 
2623                 // keys are sent
2624                 if (IS_RESPONDER(connection->sm_role)){
2625                     // slave -> receive master keys if any
2626                     if (sm_key_distribution_all_received(connection)){
2627                         sm_key_distribution_handle_all_received(connection);
2628                         connection->sm_engine_state = SM_RESPONDER_IDLE;
2629                         sm_done_for_handle(connection->sm_handle);
2630                     } else {
2631                         connection->sm_engine_state = SM_PH3_RECEIVE_KEYS;
2632                     }
2633                 } else {
2634                     // master -> all done
2635                     connection->sm_engine_state = SM_INITIATOR_CONNECTED;
2636                     sm_done_for_handle(connection->sm_handle);
2637                 }
2638                 break;
2639 
2640             default:
2641                 break;
2642         }
2643 
2644         // check again if active connection was released
2645         if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break;
2646     }
2647 }
2648 
2649 // note: aes engine is ready as we just got the aes result
2650 static void sm_handle_encryption_result(uint8_t * data){
2651 
2652     sm_aes128_state = SM_AES128_IDLE;
2653 
2654     if (sm_address_resolution_ah_calculation_active){
2655         sm_address_resolution_ah_calculation_active = 0;
2656         // compare calulated address against connecting device
2657         uint8_t hash[3];
2658         reverse_24(data, hash);
2659         if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){
2660             log_info("LE Device Lookup: matched resolvable private address");
2661             sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED);
2662             return;
2663         }
2664         // no match, try next
2665         sm_address_resolution_test++;
2666         return;
2667     }
2668 
2669     switch (dkg_state){
2670         case DKG_W4_IRK:
2671             reverse_128(data, sm_persistent_irk);
2672             log_info_key("irk", sm_persistent_irk);
2673             dkg_next_state();
2674             return;
2675         case DKG_W4_DHK:
2676             reverse_128(data, sm_persistent_dhk);
2677             log_info_key("dhk", sm_persistent_dhk);
2678             dkg_next_state();
2679             // SM Init Finished
2680             return;
2681         default:
2682             break;
2683     }
2684 
2685     switch (rau_state){
2686         case RAU_W4_ENC:
2687             reverse_24(data, &sm_random_address[3]);
2688             rau_next_state();
2689             return;
2690         default:
2691             break;
2692     }
2693 
2694 #ifdef ENABLE_CMAC_ENGINE
2695     switch (sm_cmac_state){
2696         case CMAC_W4_SUBKEYS:
2697         case CMAC_W4_MI:
2698         case CMAC_W4_MLAST:
2699             {
2700             sm_key_t t;
2701             reverse_128(data, t);
2702             sm_cmac_handle_encryption_result(t);
2703             }
2704             return;
2705         default:
2706             break;
2707     }
2708 #endif
2709 
2710     // retrieve sm_connection provided to sm_aes128_start_encryption
2711     sm_connection_t * connection = (sm_connection_t*) sm_aes128_context;
2712     if (!connection) return;
2713     switch (connection->sm_engine_state){
2714         case SM_PH2_C1_W4_ENC_A:
2715         case SM_PH2_C1_W4_ENC_C:
2716             {
2717             sm_key_t t2;
2718             reverse_128(data, t2);
2719             sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value);
2720             }
2721             sm_next_responding_state(connection);
2722             return;
2723         case SM_PH2_C1_W4_ENC_B:
2724             reverse_128(data, setup->sm_local_confirm);
2725             log_info_key("c1!", setup->sm_local_confirm);
2726             connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM;
2727             return;
2728         case SM_PH2_C1_W4_ENC_D:
2729             {
2730             sm_key_t peer_confirm_test;
2731             reverse_128(data, peer_confirm_test);
2732             log_info_key("c1!", peer_confirm_test);
2733             if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){
2734                 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED;
2735                 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
2736                 return;
2737             }
2738             if (IS_RESPONDER(connection->sm_role)){
2739                 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM;
2740             } else {
2741                 connection->sm_engine_state = SM_PH2_CALC_STK;
2742             }
2743             }
2744             return;
2745         case SM_PH2_W4_STK:
2746             reverse_128(data, setup->sm_ltk);
2747             sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size);
2748             log_info_key("stk", setup->sm_ltk);
2749             if (IS_RESPONDER(connection->sm_role)){
2750                 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY;
2751             } else {
2752                 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION;
2753             }
2754             return;
2755         case SM_PH3_Y_W4_ENC:{
2756             sm_key_t y128;
2757             reverse_128(data, y128);
2758             setup->sm_local_y = big_endian_read_16(y128, 14);
2759             log_info_hex16("y", setup->sm_local_y);
2760             // PH3B3 - calculate EDIV
2761             setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div;
2762             log_info_hex16("ediv", setup->sm_local_ediv);
2763             // PH3B4 - calculate LTK         - enc
2764             // LTK = d1(ER, DIV, 0))
2765             connection->sm_engine_state = SM_PH3_LTK_GET_ENC;
2766             return;
2767         }
2768         case SM_RESPONDER_PH4_Y_W4_ENC:{
2769             sm_key_t y128;
2770             reverse_128(data, y128);
2771             setup->sm_local_y = big_endian_read_16(y128, 14);
2772             log_info_hex16("y", setup->sm_local_y);
2773 
2774             // PH3B3 - calculate DIV
2775             setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv;
2776             log_info_hex16("ediv", setup->sm_local_ediv);
2777             // PH3B4 - calculate LTK         - enc
2778             // LTK = d1(ER, DIV, 0))
2779             connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC;
2780             return;
2781         }
2782         case SM_PH3_LTK_W4_ENC:
2783             reverse_128(data, setup->sm_ltk);
2784             log_info_key("ltk", setup->sm_ltk);
2785             // calc CSRK next
2786             connection->sm_engine_state = SM_PH3_CSRK_GET_ENC;
2787             return;
2788         case SM_PH3_CSRK_W4_ENC:
2789             reverse_128(data, setup->sm_local_csrk);
2790             log_info_key("csrk", setup->sm_local_csrk);
2791             if (setup->sm_key_distribution_send_set){
2792                 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS;
2793             } else {
2794                 // no keys to send, just continue
2795                 if (IS_RESPONDER(connection->sm_role)){
2796                     // slave -> receive master keys
2797                     connection->sm_engine_state = SM_PH3_RECEIVE_KEYS;
2798                 } else {
2799                     if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){
2800                         connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK;
2801                     } else {
2802                         // master -> all done
2803                         connection->sm_engine_state = SM_INITIATOR_CONNECTED;
2804                         sm_done_for_handle(connection->sm_handle);
2805                     }
2806                 }
2807             }
2808             return;
2809 #ifdef ENABLE_LE_PERIPHERAL
2810         case SM_RESPONDER_PH4_LTK_W4_ENC:
2811             reverse_128(data, setup->sm_ltk);
2812             sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size);
2813             log_info_key("ltk", setup->sm_ltk);
2814             connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY;
2815             return;
2816 #endif
2817         default:
2818             break;
2819     }
2820 }
2821 
2822 #ifdef ENABLE_LE_SECURE_CONNECTIONS
2823 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
2824 #if !defined(WICED_VERSION)
2825 // @return OK
2826 static int sm_generate_f_rng(unsigned char * buffer, unsigned size){
2827     if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0;
2828     int offset = setup->sm_passkey_bit;
2829     log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset);
2830     while (size) {
2831         *buffer++ = setup->sm_peer_q[offset++];
2832         size--;
2833     }
2834     setup->sm_passkey_bit = offset;
2835     return 1;
2836 }
2837 #endif
2838 #endif
2839 #endif
2840 
2841 // note: random generator is ready. this doesn NOT imply that aes engine is unused!
2842 static void sm_handle_random_result(uint8_t * data){
2843 
2844 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS)
2845 
2846     if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){
2847         int num_bytes = setup->sm_passkey_bit;
2848         memcpy(&setup->sm_peer_q[num_bytes], data, 8);
2849         num_bytes += 8;
2850         setup->sm_passkey_bit = num_bytes;
2851 
2852         if (num_bytes >= 64){
2853 
2854             // init pre-generated random data from sm_peer_q
2855             setup->sm_passkey_bit = 0;
2856 
2857             // generate EC key
2858 #ifndef WICED_VERSION
2859             log_info("set uECC RNG for initial key generation with 64 random bytes");
2860             // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it
2861             uECC_set_rng(&sm_generate_f_rng);
2862 #endif /* WICED_VERSION */
2863 
2864 #if uECC_SUPPORTS_secp256r1
2865             // standard version
2866             uECC_make_key(ec_q, ec_d, uECC_secp256r1());
2867 
2868             // disable RNG again, as returning no randmon data lets shared key generation fail
2869             log_info("disable uECC RNG in standard version after key generation");
2870             uECC_set_rng(NULL);
2871 #else
2872             // static version
2873             uECC_make_key(ec_q, ec_d);
2874 #endif /* ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS */
2875 
2876             ec_key_generation_state = EC_KEY_GENERATION_DONE;
2877             log_info("Elliptic curve: d");
2878             log_info_hexdump(ec_d,32);
2879             sm_log_ec_keypair();
2880         }
2881     }
2882 #endif
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                     break;
3255                 default:
3256                     break;
3257 			}
3258             break;
3259         default:
3260             break;
3261 	}
3262 
3263     sm_run();
3264 }
3265 
3266 static inline int sm_calc_actual_encryption_key_size(int other){
3267     if (other < sm_min_encryption_key_size) return 0;
3268     if (other < sm_max_encryption_key_size) return other;
3269     return sm_max_encryption_key_size;
3270 }
3271 
3272 
3273 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3274 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){
3275     switch (method){
3276         case JUST_WORKS:
3277         case NK_BOTH_INPUT:
3278             return 1;
3279         default:
3280             return 0;
3281     }
3282 }
3283 // responder
3284 
3285 static int sm_passkey_used(stk_generation_method_t method){
3286     switch (method){
3287         case PK_RESP_INPUT:
3288             return 1;
3289         default:
3290             return 0;
3291     }
3292 }
3293 #endif
3294 
3295 /**
3296  * @return ok
3297  */
3298 static int sm_validate_stk_generation_method(void){
3299     // check if STK generation method is acceptable by client
3300     switch (setup->sm_stk_generation_method){
3301         case JUST_WORKS:
3302             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0;
3303         case PK_RESP_INPUT:
3304         case PK_INIT_INPUT:
3305         case OK_BOTH_INPUT:
3306             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0;
3307         case OOB:
3308             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0;
3309         case NK_BOTH_INPUT:
3310             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0;
3311             return 1;
3312         default:
3313             return 0;
3314     }
3315 }
3316 
3317 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){
3318 
3319     UNUSED(size);
3320 
3321     if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){
3322         sm_run();
3323     }
3324 
3325     if (packet_type != SM_DATA_PACKET) return;
3326 
3327     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3328     if (!sm_conn) return;
3329 
3330     if (packet[0] == SM_CODE_PAIRING_FAILED){
3331         sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED;
3332         return;
3333     }
3334 
3335     log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]);
3336 
3337     int err;
3338     UNUSED(err);
3339 
3340     if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){
3341         uint8_t buffer[5];
3342         buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION;
3343         buffer[1] = 3;
3344         little_endian_store_16(buffer, 2, con_handle);
3345         buffer[4] = packet[1];
3346         sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer));
3347         return;
3348     }
3349 
3350     switch (sm_conn->sm_engine_state){
3351 
3352         // a sm timeout requries a new physical connection
3353         case SM_GENERAL_TIMEOUT:
3354             return;
3355 
3356 #ifdef ENABLE_LE_CENTRAL
3357 
3358         // Initiator
3359         case SM_INITIATOR_CONNECTED:
3360             if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){
3361                 sm_pdu_received_in_wrong_state(sm_conn);
3362                 break;
3363             }
3364             if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){
3365                 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3366                 break;
3367             }
3368             if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){
3369                 sm_key_t ltk;
3370                 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL);
3371                 if (!sm_is_null_key(ltk)){
3372                     log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index);
3373                     sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
3374                 } else {
3375                     sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3376                 }
3377                 break;
3378             }
3379             // otherwise, store security request
3380             sm_conn->sm_security_request_received = 1;
3381             break;
3382 
3383         case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE:
3384             if (packet[0] != SM_CODE_PAIRING_RESPONSE){
3385                 sm_pdu_received_in_wrong_state(sm_conn);
3386                 break;
3387             }
3388             // store pairing request
3389             memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t));
3390             err = sm_stk_generation_init(sm_conn);
3391             if (err){
3392                 setup->sm_pairing_failed_reason = err;
3393                 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
3394                 break;
3395             }
3396 
3397             // generate random number first, if we need to show passkey
3398             if (setup->sm_stk_generation_method == PK_RESP_INPUT){
3399                 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK;
3400                 break;
3401             }
3402 
3403 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3404             if (setup->sm_use_secure_connections){
3405                 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged
3406                 if (setup->sm_stk_generation_method == JUST_WORKS){
3407                     sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3408                     sm_trigger_user_response(sm_conn);
3409                     if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){
3410                         sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3411                     }
3412                 } else {
3413                     sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3414                 }
3415                 break;
3416             }
3417 #endif
3418             sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3419             sm_trigger_user_response(sm_conn);
3420             // response_idle == nothing <--> sm_trigger_user_response() did not require response
3421             if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){
3422                 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3423             }
3424             break;
3425 
3426         case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM:
3427             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3428                 sm_pdu_received_in_wrong_state(sm_conn);
3429                 break;
3430             }
3431 
3432             // store s_confirm
3433             reverse_128(&packet[1], setup->sm_peer_confirm);
3434             sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM;
3435             break;
3436 
3437         case SM_INITIATOR_PH2_W4_PAIRING_RANDOM:
3438             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3439                 sm_pdu_received_in_wrong_state(sm_conn);
3440                 break;;
3441             }
3442 
3443             // received random value
3444             reverse_128(&packet[1], setup->sm_peer_random);
3445             sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C;
3446             break;
3447 #endif
3448 
3449 #ifdef ENABLE_LE_PERIPHERAL
3450         // Responder
3451         case SM_RESPONDER_IDLE:
3452         case SM_RESPONDER_SEND_SECURITY_REQUEST:
3453         case SM_RESPONDER_PH1_W4_PAIRING_REQUEST:
3454             if (packet[0] != SM_CODE_PAIRING_REQUEST){
3455                 sm_pdu_received_in_wrong_state(sm_conn);
3456                 break;;
3457             }
3458 
3459             // store pairing request
3460             memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t));
3461             sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED;
3462             break;
3463 #endif
3464 
3465 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3466         case SM_SC_W4_PUBLIC_KEY_COMMAND:
3467             if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){
3468                 sm_pdu_received_in_wrong_state(sm_conn);
3469                 break;
3470             }
3471 
3472             // store public key for DH Key calculation
3473             reverse_256(&packet[01], &setup->sm_peer_q[0]);
3474             reverse_256(&packet[33], &setup->sm_peer_q[32]);
3475 
3476 #ifdef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
3477             // validate public key
3478             err = 0;
3479 #if uECC_SUPPORTS_secp256r1
3480             // standard version
3481             err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0;
3482 #else
3483             // static version
3484             err = uECC_valid_public_key(setup->sm_peer_q) == 0;
3485 #endif
3486             if (err){
3487                 log_error("sm: peer public key invalid %x", err);
3488                 // uses "unspecified reason", there is no "public key invalid" error code
3489                 sm_pdu_received_in_wrong_state(sm_conn);
3490                 break;
3491             }
3492 #endif
3493 
3494 #ifndef ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS
3495             // start calculating dhkey
3496             setup->sm_state_vars |= SM_STATE_VAR_DHKEY_NEEDED;
3497 #endif
3498 
3499             if (IS_RESPONDER(sm_conn->sm_role)){
3500                 // responder
3501                 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3502             } else {
3503                 // initiator
3504                 // stk generation method
3505                 // passkey entry: notify app to show passkey or to request passkey
3506                 switch (setup->sm_stk_generation_method){
3507                     case JUST_WORKS:
3508                     case NK_BOTH_INPUT:
3509                         sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION;
3510                         break;
3511                     case PK_RESP_INPUT:
3512                         sm_sc_start_calculating_local_confirm(sm_conn);
3513                         break;
3514                     case PK_INIT_INPUT:
3515                     case OK_BOTH_INPUT:
3516                         if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){
3517                             sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
3518                             break;
3519                         }
3520                         sm_sc_start_calculating_local_confirm(sm_conn);
3521                         break;
3522                     case OOB:
3523                         // TODO: implement SC OOB
3524                         break;
3525                 }
3526             }
3527             break;
3528 
3529         case SM_SC_W4_CONFIRMATION:
3530             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3531                 sm_pdu_received_in_wrong_state(sm_conn);
3532                 break;
3533             }
3534             // received confirm value
3535             reverse_128(&packet[1], setup->sm_peer_confirm);
3536 
3537             if (IS_RESPONDER(sm_conn->sm_role)){
3538                 // responder
3539                 if (sm_passkey_used(setup->sm_stk_generation_method)){
3540                     if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){
3541                         // still waiting for passkey
3542                         sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE;
3543                         break;
3544                     }
3545                 }
3546                 sm_sc_start_calculating_local_confirm(sm_conn);
3547             } else {
3548                 // initiator
3549                 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){
3550                     sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A;
3551                 } else {
3552                     sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM;
3553                 }
3554             }
3555             break;
3556 
3557         case SM_SC_W4_PAIRING_RANDOM:
3558             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3559                 sm_pdu_received_in_wrong_state(sm_conn);
3560                 break;
3561             }
3562 
3563             // received random value
3564             reverse_128(&packet[1], setup->sm_peer_nonce);
3565 
3566             // validate confirm value if Cb = f4(Pkb, Pka, Nb, z)
3567             // only check for JUST WORK/NC in initiator role AND passkey entry
3568             if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) {
3569                  sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION;
3570             }
3571 
3572             sm_sc_state_after_receiving_random(sm_conn);
3573             break;
3574 
3575         case SM_SC_W2_CALCULATE_G2:
3576         case SM_SC_W4_CALCULATE_G2:
3577         case SM_SC_W4_CALCULATE_DHKEY:
3578         case SM_SC_W2_CALCULATE_F5_SALT:
3579         case SM_SC_W4_CALCULATE_F5_SALT:
3580         case SM_SC_W2_CALCULATE_F5_MACKEY:
3581         case SM_SC_W4_CALCULATE_F5_MACKEY:
3582         case SM_SC_W2_CALCULATE_F5_LTK:
3583         case SM_SC_W4_CALCULATE_F5_LTK:
3584         case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK:
3585         case SM_SC_W4_DHKEY_CHECK_COMMAND:
3586         case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK:
3587             if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){
3588                 sm_pdu_received_in_wrong_state(sm_conn);
3589                 break;
3590             }
3591             // store DHKey Check
3592             setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED;
3593             reverse_128(&packet[01], setup->sm_peer_dhkey_check);
3594 
3595             // have we been only waiting for dhkey check command?
3596             if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){
3597                 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK;
3598             }
3599             break;
3600 #endif
3601 
3602 #ifdef ENABLE_LE_PERIPHERAL
3603         case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM:
3604             if (packet[0] != SM_CODE_PAIRING_CONFIRM){
3605                 sm_pdu_received_in_wrong_state(sm_conn);
3606                 break;
3607             }
3608 
3609             // received confirm value
3610             reverse_128(&packet[1], setup->sm_peer_confirm);
3611 
3612             // notify client to hide shown passkey
3613             if (setup->sm_stk_generation_method == PK_INIT_INPUT){
3614                 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address);
3615             }
3616 
3617             // handle user cancel pairing?
3618             if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){
3619                 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED;
3620                 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED;
3621                 break;
3622             }
3623 
3624             // wait for user action?
3625             if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){
3626                 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE;
3627                 break;
3628             }
3629 
3630             // calculate and send local_confirm
3631             sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3632             break;
3633 
3634         case SM_RESPONDER_PH2_W4_PAIRING_RANDOM:
3635             if (packet[0] != SM_CODE_PAIRING_RANDOM){
3636                 sm_pdu_received_in_wrong_state(sm_conn);
3637                 break;;
3638             }
3639 
3640             // received random value
3641             reverse_128(&packet[1], setup->sm_peer_random);
3642             sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C;
3643             break;
3644 #endif
3645 
3646         case SM_PH3_RECEIVE_KEYS:
3647             switch(packet[0]){
3648                 case SM_CODE_ENCRYPTION_INFORMATION:
3649                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION;
3650                     reverse_128(&packet[1], setup->sm_peer_ltk);
3651                     break;
3652 
3653                 case SM_CODE_MASTER_IDENTIFICATION:
3654                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION;
3655                     setup->sm_peer_ediv = little_endian_read_16(packet, 1);
3656                     reverse_64(&packet[3], setup->sm_peer_rand);
3657                     break;
3658 
3659                 case SM_CODE_IDENTITY_INFORMATION:
3660                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION;
3661                     reverse_128(&packet[1], setup->sm_peer_irk);
3662                     break;
3663 
3664                 case SM_CODE_IDENTITY_ADDRESS_INFORMATION:
3665                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION;
3666                     setup->sm_peer_addr_type = packet[1];
3667                     reverse_bd_addr(&packet[2], setup->sm_peer_address);
3668                     break;
3669 
3670                 case SM_CODE_SIGNING_INFORMATION:
3671                     setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION;
3672                     reverse_128(&packet[1], setup->sm_peer_csrk);
3673                     break;
3674                 default:
3675                     // Unexpected PDU
3676                     log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]);
3677                     break;
3678             }
3679             // done with key distribution?
3680             if (sm_key_distribution_all_received(sm_conn)){
3681 
3682                 sm_key_distribution_handle_all_received(sm_conn);
3683 
3684                 if (IS_RESPONDER(sm_conn->sm_role)){
3685                     if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){
3686                         sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK;
3687                     } else {
3688                         sm_conn->sm_engine_state = SM_RESPONDER_IDLE;
3689                         sm_done_for_handle(sm_conn->sm_handle);
3690                     }
3691                 } else {
3692                     if (setup->sm_use_secure_connections){
3693                         sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS;
3694                     } else {
3695                         sm_conn->sm_engine_state = SM_PH3_GET_RANDOM;
3696                     }
3697                 }
3698             }
3699             break;
3700         default:
3701             // Unexpected PDU
3702             log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state);
3703             break;
3704     }
3705 
3706     // try to send preparared packet
3707     sm_run();
3708 }
3709 
3710 // Security Manager Client API
3711 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){
3712     sm_get_oob_data = get_oob_data_callback;
3713 }
3714 
3715 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){
3716     btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler);
3717 }
3718 
3719 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){
3720     sm_accepted_stk_generation_methods = accepted_stk_generation_methods;
3721 }
3722 
3723 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){
3724 	sm_min_encryption_key_size = min_size;
3725 	sm_max_encryption_key_size = max_size;
3726 }
3727 
3728 void sm_set_authentication_requirements(uint8_t auth_req){
3729     sm_auth_req = auth_req;
3730 }
3731 
3732 void sm_set_io_capabilities(io_capability_t io_capability){
3733     sm_io_capabilities = io_capability;
3734 }
3735 
3736 #ifdef ENABLE_LE_PERIPHERAL
3737 void sm_set_request_security(int enable){
3738     sm_slave_request_security = enable;
3739 }
3740 #endif
3741 
3742 void sm_set_er(sm_key_t er){
3743     memcpy(sm_persistent_er, er, 16);
3744 }
3745 
3746 void sm_set_ir(sm_key_t ir){
3747     memcpy(sm_persistent_ir, ir, 16);
3748 }
3749 
3750 // Testing support only
3751 void sm_test_set_irk(sm_key_t irk){
3752     memcpy(sm_persistent_irk, irk, 16);
3753     sm_persistent_irk_ready = 1;
3754 }
3755 
3756 void sm_test_use_fixed_local_csrk(void){
3757     test_use_fixed_local_csrk = 1;
3758 }
3759 
3760 void sm_init(void){
3761     // set some (BTstack default) ER and IR
3762     int i;
3763     sm_key_t er;
3764     sm_key_t ir;
3765     for (i=0;i<16;i++){
3766         er[i] = 0x30 + i;
3767         ir[i] = 0x90 + i;
3768     }
3769     sm_set_er(er);
3770     sm_set_ir(ir);
3771     // defaults
3772     sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS
3773                                        | SM_STK_GENERATION_METHOD_OOB
3774                                        | SM_STK_GENERATION_METHOD_PASSKEY
3775                                        | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON;
3776 
3777     sm_max_encryption_key_size = 16;
3778     sm_min_encryption_key_size = 7;
3779 
3780 #ifdef ENABLE_CMAC_ENGINE
3781     sm_cmac_state  = CMAC_IDLE;
3782 #endif
3783     dkg_state = DKG_W4_WORKING;
3784     rau_state = RAU_W4_WORKING;
3785     sm_aes128_state = SM_AES128_IDLE;
3786     sm_address_resolution_test = -1;    // no private address to resolve yet
3787     sm_address_resolution_ah_calculation_active = 0;
3788     sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE;
3789     sm_address_resolution_general_queue = NULL;
3790 
3791     gap_random_adress_update_period = 15 * 60 * 1000L;
3792     sm_active_connection_handle = HCI_CON_HANDLE_INVALID;
3793 
3794     test_use_fixed_local_csrk = 0;
3795 
3796     // register for HCI Events from HCI
3797     hci_event_callback_registration.callback = &sm_event_packet_handler;
3798     hci_add_event_handler(&hci_event_callback_registration);
3799 
3800     // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW
3801     l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL);
3802 
3803 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3804     ec_key_generation_state = EC_KEY_GENERATION_IDLE;
3805 #endif
3806 }
3807 
3808 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){
3809 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3810     memcpy(&ec_q[0],  qx, 32);
3811     memcpy(&ec_q[32], qy, 32);
3812     memcpy(ec_d, d, 32);
3813     sm_have_ec_keypair = 1;
3814     ec_key_generation_state = EC_KEY_GENERATION_DONE;
3815 #else
3816     UNUSED(qx);
3817     UNUSED(qy);
3818     UNUSED(d);
3819 #endif
3820 }
3821 
3822 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3823 static void parse_hex(uint8_t * buffer, const char * hex_string){
3824     while (*hex_string){
3825         int high_nibble = nibble_for_char(*hex_string++);
3826         int low_nibble  = nibble_for_char(*hex_string++);
3827         *buffer++       = (high_nibble << 4) | low_nibble;
3828     }
3829 }
3830 #endif
3831 
3832 void sm_test_use_fixed_ec_keypair(void){
3833 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3834     const char * ec_d_string =  "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd";
3835     const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6";
3836     const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b";
3837     parse_hex(ec_d, ec_d_string);
3838     parse_hex(&ec_q[0],  ec_qx_string);
3839     parse_hex(&ec_q[32], ec_qy_string);
3840     sm_have_ec_keypair = 1;
3841     ec_key_generation_state = EC_KEY_GENERATION_DONE;
3842 #endif
3843 }
3844 
3845 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){
3846     hci_connection_t * hci_con = hci_connection_for_handle(con_handle);
3847     if (!hci_con) return NULL;
3848     return &hci_con->sm_connection;
3849 }
3850 
3851 // @returns 0 if not encrypted, 7-16 otherwise
3852 int sm_encryption_key_size(hci_con_handle_t con_handle){
3853     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3854     if (!sm_conn) return 0;     // wrong connection
3855     if (!sm_conn->sm_connection_encrypted) return 0;
3856     return sm_conn->sm_actual_encryption_key_size;
3857 }
3858 
3859 int sm_authenticated(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; // unencrypted connection cannot be authenticated
3863     return sm_conn->sm_connection_authenticated;
3864 }
3865 
3866 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){
3867     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3868     if (!sm_conn) return AUTHORIZATION_UNKNOWN;     // wrong connection
3869     if (!sm_conn->sm_connection_encrypted)               return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized
3870     if (!sm_conn->sm_connection_authenticated)           return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized
3871     return sm_conn->sm_connection_authorization_state;
3872 }
3873 
3874 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){
3875     switch (sm_conn->sm_engine_state){
3876         case SM_GENERAL_IDLE:
3877         case SM_RESPONDER_IDLE:
3878             sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST;
3879             sm_run();
3880             break;
3881         default:
3882             break;
3883     }
3884 }
3885 
3886 /**
3887  * @brief Trigger Security Request
3888  */
3889 void sm_send_security_request(hci_con_handle_t con_handle){
3890     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3891     if (!sm_conn) return;
3892     sm_send_security_request_for_connection(sm_conn);
3893 }
3894 
3895 // request pairing
3896 void sm_request_pairing(hci_con_handle_t con_handle){
3897     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3898     if (!sm_conn) return;     // wrong connection
3899 
3900     log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state);
3901     if (IS_RESPONDER(sm_conn->sm_role)){
3902         sm_send_security_request_for_connection(sm_conn);
3903     } else {
3904         // used as a trigger to start central/master/initiator security procedures
3905         uint16_t ediv;
3906         sm_key_t ltk;
3907         if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){
3908             switch (sm_conn->sm_irk_lookup_state){
3909                 case IRK_LOOKUP_FAILED:
3910                     sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3911                     break;
3912                 case IRK_LOOKUP_SUCCEEDED:
3913                         le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL);
3914                         if (!sm_is_null_key(ltk) || ediv){
3915                             log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index);
3916                             sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK;
3917                         } else {
3918                             sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST;
3919                         }
3920                         break;
3921                 default:
3922                     sm_conn->sm_bonding_requested = 1;
3923                     break;
3924             }
3925         } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){
3926             sm_conn->sm_bonding_requested = 1;
3927         }
3928     }
3929     sm_run();
3930 }
3931 
3932 // called by client app on authorization request
3933 void sm_authorization_decline(hci_con_handle_t con_handle){
3934     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3935     if (!sm_conn) return;     // wrong connection
3936     sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED;
3937     sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0);
3938 }
3939 
3940 void sm_authorization_grant(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_GRANTED;
3944     sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1);
3945 }
3946 
3947 // GAP Bonding API
3948 
3949 void sm_bonding_decline(hci_con_handle_t con_handle){
3950     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3951     if (!sm_conn) return;     // wrong connection
3952     setup->sm_user_response = SM_USER_RESPONSE_DECLINE;
3953 
3954     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
3955         switch (setup->sm_stk_generation_method){
3956             case PK_RESP_INPUT:
3957             case PK_INIT_INPUT:
3958             case OK_BOTH_INPUT:
3959                 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED);
3960                 break;
3961             case NK_BOTH_INPUT:
3962                 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED);
3963                 break;
3964             case JUST_WORKS:
3965             case OOB:
3966                 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON);
3967                 break;
3968         }
3969     }
3970     sm_run();
3971 }
3972 
3973 void sm_just_works_confirm(hci_con_handle_t con_handle){
3974     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
3975     if (!sm_conn) return;     // wrong connection
3976     setup->sm_user_response = SM_USER_RESPONSE_CONFIRM;
3977     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
3978         if (setup->sm_use_secure_connections){
3979             sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND;
3980         } else {
3981             sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
3982         }
3983     }
3984 
3985 #ifdef ENABLE_LE_SECURE_CONNECTIONS
3986     if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){
3987         sm_sc_prepare_dhkey_check(sm_conn);
3988     }
3989 #endif
3990 
3991     sm_run();
3992 }
3993 
3994 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){
3995     // for now, it's the same
3996     sm_just_works_confirm(con_handle);
3997 }
3998 
3999 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){
4000     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4001     if (!sm_conn) return;     // wrong connection
4002     sm_reset_tk();
4003     big_endian_store_32(setup->sm_tk, 12, passkey);
4004     setup->sm_user_response = SM_USER_RESPONSE_PASSKEY;
4005     if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){
4006         sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A;
4007     }
4008 #ifdef ENABLE_LE_SECURE_CONNECTIONS
4009     memcpy(setup->sm_ra, setup->sm_tk, 16);
4010     memcpy(setup->sm_rb, setup->sm_tk, 16);
4011     if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){
4012         sm_sc_start_calculating_local_confirm(sm_conn);
4013     }
4014 #endif
4015     sm_run();
4016 }
4017 
4018 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){
4019     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4020     if (!sm_conn) return;     // wrong connection
4021     if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return;
4022     setup->sm_keypress_notification = action;
4023     sm_run();
4024 }
4025 
4026 /**
4027  * @brief Identify device in LE Device DB
4028  * @param handle
4029  * @returns index from le_device_db or -1 if not found/identified
4030  */
4031 int sm_le_device_index(hci_con_handle_t con_handle ){
4032     sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle);
4033     if (!sm_conn) return -1;
4034     return sm_conn->sm_le_db_index;
4035 }
4036 
4037 static int gap_random_address_type_requires_updates(void){
4038     if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0;
4039     if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0;
4040     return 1;
4041 }
4042 
4043 static uint8_t own_address_type(void){
4044     switch (gap_random_adress_type){
4045         case GAP_RANDOM_ADDRESS_TYPE_OFF:
4046             return BD_ADDR_TYPE_LE_PUBLIC;
4047         default:
4048             return BD_ADDR_TYPE_LE_RANDOM;
4049     }
4050 }
4051 
4052 // GAP LE API
4053 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){
4054     gap_random_address_update_stop();
4055     gap_random_adress_type = random_address_type;
4056     hci_le_set_own_address_type(own_address_type());
4057     if (!gap_random_address_type_requires_updates()) return;
4058     gap_random_address_update_start();
4059     gap_random_address_trigger();
4060 }
4061 
4062 gap_random_address_type_t gap_random_address_get_mode(void){
4063     return gap_random_adress_type;
4064 }
4065 
4066 void gap_random_address_set_update_period(int period_ms){
4067     gap_random_adress_update_period = period_ms;
4068     if (!gap_random_address_type_requires_updates()) return;
4069     gap_random_address_update_stop();
4070     gap_random_address_update_start();
4071 }
4072 
4073 void gap_random_address_set(bd_addr_t addr){
4074     gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC);
4075     memcpy(sm_random_address, addr, 6);
4076     if (rau_state == RAU_W4_WORKING) return;
4077     rau_state = RAU_SET_ADDRESS;
4078     sm_run();
4079 }
4080 
4081 #ifdef ENABLE_LE_PERIPHERAL
4082 /*
4083  * @brief Set Advertisement Paramters
4084  * @param adv_int_min
4085  * @param adv_int_max
4086  * @param adv_type
4087  * @param direct_address_type
4088  * @param direct_address
4089  * @param channel_map
4090  * @param filter_policy
4091  *
4092  * @note own_address_type is used from gap_random_address_set_mode
4093  */
4094 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type,
4095     uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){
4096     hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type,
4097         direct_address_typ, direct_address, channel_map, filter_policy);
4098 }
4099 #endif
4100 
4101