xref: /btstack/src/mesh/mesh_network.c (revision a0ecb5f3e03de203431a83bfb88217ac1247ef71)
1 /*
2  * Copyright (C) 2018 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__ "mesh_network.c"
39 
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 
44 #include "btstack_debug.h"
45 #include "btstack_event.h"
46 #include "btstack_memory.h"
47 #include "btstack_util.h"
48 
49 #include "mesh/beacon.h"
50 #include "mesh/mesh_foundation.h"
51 #include "mesh/mesh_iv_index_seq_number.h"
52 #include "mesh/mesh_keys.h"
53 #include "mesh/mesh_node.h"
54 #include "mesh/provisioning.h"
55 #include "mesh/provisioning_device.h"
56 
57 #ifdef ENABLE_MESH_ADV_BEARER
58 #include "mesh/adv_bearer.h"
59 #endif
60 
61 #ifdef ENABLE_MESH_GATT_BEARER
62 #include "mesh/gatt_bearer.h"
63 #endif
64 
65 // configuration
66 #define MESH_NETWORK_CACHE_SIZE 2
67 
68 // debug config
69 // #define LOG_NETWORK
70 
71 static void mesh_network_dump_network_pdus(const char * name, btstack_linked_list_t * list);
72 
73 // structs
74 
75 // globals
76 
77 static void (*mesh_network_higher_layer_handler)(mesh_network_callback_type_t callback_type, mesh_network_pdu_t * network_pdu);
78 static void (*mesh_network_proxy_message_handler)(mesh_network_callback_type_t callback_type, mesh_network_pdu_t * network_pdu);
79 
80 #ifdef ENABLE_MESH_GATT_BEARER
81 static hci_con_handle_t gatt_bearer_con_handle;
82 #endif
83 
84 // shared send/receive crypto
85 static int mesh_crypto_active;
86 
87 // crypto requests
88 static union {
89     btstack_crypto_ccm_t         ccm;
90     btstack_crypto_aes128_t      aes128;
91 } mesh_network_crypto_request;
92 
93 static const mesh_network_key_t *  current_network_key;
94 
95 // PECB calculation
96 static uint8_t encryption_block[16];
97 static uint8_t obfuscation_block[16];
98 
99 // Subnets
100 static btstack_linked_list_t subnets;
101 
102 // Network Nonce
103 static uint8_t network_nonce[13];
104 
105 // INCOMING //
106 
107 // unprocessed network pdu - added by mesh_network_pdus_received_message
108 static btstack_linked_list_t        network_pdus_received;
109 
110 // in validation
111 static mesh_network_pdu_t *         incoming_pdu_raw;
112 static mesh_network_pdu_t *         incoming_pdu_decoded;
113 static mesh_network_key_iterator_t  validation_network_key_it;
114 
115 // OUTGOING //
116 
117 // Network PDUs queued by mesh_network_send
118 static btstack_linked_list_t network_pdus_queued;
119 
120 // Network PDU about to get send via all bearers when encrypted
121 static mesh_network_pdu_t * outgoing_pdu;
122 
123 // Network PDUs ready to send via GATT Bearer
124 static btstack_linked_list_t network_pdus_outgoing_gatt;
125 
126 #ifdef ENABLE_MESH_GATT_BEARER
127 static mesh_network_pdu_t * gatt_bearer_network_pdu;
128 #endif
129 
130 // Network PDUs ready to send via ADV Bearer
131 static btstack_linked_list_t network_pdus_outgoing_adv;
132 
133 #ifdef ENABLE_MESH_ADV_BEARER
134 static mesh_network_pdu_t * adv_bearer_network_pdu;
135 #endif
136 
137 
138 // mesh network cache - we use 32-bit 'hashes'
139 static uint32_t mesh_network_cache[MESH_NETWORK_CACHE_SIZE];
140 static int      mesh_network_cache_index;
141 
142 // prototypes
143 
144 static void mesh_network_run(void);
145 static void process_network_pdu_validate(void);
146 
147 // network caching
148 static uint32_t mesh_network_cache_hash(mesh_network_pdu_t * network_pdu){
149     // - The SEQ field is a 24-bit integer that when combined with the IV Index,
150     // shall be a unique value for each new Network PDU originated by this node (=> SRC)
151     // - IV updates only rarely
152     // => 16 bit SRC, 1 bit IVI, 15 bit SEQ
153     uint8_t  ivi = network_pdu->data[0] >> 7;
154     uint16_t seq = big_endian_read_16(network_pdu->data, 3);
155     uint16_t src = big_endian_read_16(network_pdu->data, 5);
156     return (src << 16) | (ivi << 15) | (seq & 0x7fff);
157 }
158 
159 static int mesh_network_cache_find(uint32_t hash){
160     int i;
161     for (i = 0; i < MESH_NETWORK_CACHE_SIZE; i++) {
162         if (mesh_network_cache[i] == hash) {
163             return 1;
164         }
165     }
166     return 0;
167 }
168 
169 static void mesh_network_cache_add(uint32_t hash){
170     mesh_network_cache[mesh_network_cache_index++] = hash;
171     if (mesh_network_cache_index >= MESH_NETWORK_CACHE_SIZE){
172         mesh_network_cache_index = 0;
173     }
174 }
175 
176 // common helper
177 int mesh_network_address_unicast(uint16_t addr){
178     return addr != MESH_ADDRESS_UNSASSIGNED && (addr < 0x8000);
179 }
180 
181 int mesh_network_address_virtual(uint16_t addr){
182     return (addr & 0xC000) == 0x8000;   // 0b10xx xxxx xxxx xxxx
183 }
184 
185 int mesh_network_address_group(uint16_t addr){
186     return (addr & 0xC000) == 0xC000;   // 0b11xx xxxx xxxx xxxx
187 }
188 
189 int mesh_network_address_all_proxies(uint16_t addr){
190     return addr == MESH_ADDRESS_ALL_PROXIES;
191 }
192 
193 int mesh_network_address_all_nodes(uint16_t addr){
194     return addr == MESH_ADDRESS_ALL_NODES;
195 }
196 
197 int mesh_network_address_all_friends(uint16_t addr){
198     return addr == MESH_ADDRESS_ALL_FRIENDS;
199 }
200 
201 int mesh_network_address_all_relays(uint16_t addr){
202     return addr == MESH_ADDRESS_ALL_RELAYS;
203 }
204 
205 int mesh_network_addresses_valid(uint8_t ctl, uint16_t src, uint16_t dst){
206     // printf("CTL: %u\n", ctl);
207     // printf("SRC: %04x\n", src);
208     // printf("DST: %04x\n", dst);
209     if (src == 0){
210         // printf("SRC Unassigned Addr -> ignore\n");
211         return 0;
212     }
213     if ((src & 0xC000) == 0x8000){
214         // printf("SRC Virtual Addr -> ignore\n");
215         return 0;
216     }
217     if ((src & 0xC000) == 0xC000){
218         // printf("SRC Group Addr -> ignore\n");
219         return 0;
220     }
221     if (dst == 0){
222         // printf("DST Unassigned Addr -> ignore\n");
223         return 0;
224     }
225     if ( ((dst & 0xC000) == 0x8000) && (ctl == 1)){
226         // printf("DST Virtual Addr in CONTROL -> ignore\n");
227         return 0;
228     }
229     if ( (0xFF00 <= dst) && (dst <= 0xfffb) && (ctl == 0) ){
230         // printf("DST RFU Group Addr in MESSAGE -> ignore\n");
231         return 0;
232     }
233     // printf("SRC + DST Addr valid\n");
234     return 1;
235 }
236 
237 static void mesh_network_create_nonce(uint8_t * nonce, const mesh_network_pdu_t * pdu, uint32_t iv_index){
238     unsigned int pos = 0;
239     nonce[pos++] = 0x0;      // Network Nonce
240     memcpy(&nonce[pos], &pdu->data[1], 6);
241     pos += 6;
242     big_endian_store_16(nonce, pos, 0);
243     pos += 2;
244     big_endian_store_32(nonce, pos, iv_index);
245 }
246 
247 static void mesh_proxy_create_nonce(uint8_t * nonce, const mesh_network_pdu_t * pdu, uint32_t iv_index){
248     unsigned int pos = 0;
249     nonce[pos++] = 0x3;      // Proxy Nonce
250     nonce[pos++] = 0;
251     memcpy(&nonce[pos], &pdu->data[2], 5);
252     pos += 5;
253     big_endian_store_16(nonce, pos, 0);
254     pos += 2;
255     big_endian_store_32(nonce, pos, iv_index);
256 }
257 
258 // NID/IVI | obfuscated (CTL/TTL, SEQ (24), SRC (16) ), encrypted ( DST(16), TransportPDU), MIC(32 or 64)
259 
260 static void mesh_network_send_d(mesh_network_pdu_t * network_pdu){
261 
262 #ifdef LOG_NETWORK
263     printf("TX-D-NetworkPDU (%p): ", network_pdu);
264     printf_hexdump(network_pdu->data, network_pdu->len);
265 #endif
266 
267     // add to queue
268     btstack_linked_list_add_tail(&network_pdus_outgoing_gatt, (btstack_linked_item_t *) network_pdu);
269 
270     // go
271     mesh_network_run();
272 }
273 
274 // new
275 static void mesh_network_send_c(void *arg){
276     UNUSED(arg);
277 
278     // obfuscate
279     unsigned int i;
280     for (i=0;i<6;i++){
281         outgoing_pdu->data[1+i] ^= obfuscation_block[i];
282     }
283 
284 #ifdef LOG_NETWORK
285     printf("TX-C-NetworkPDU (%p): ", outgoing_pdu);
286     printf_hexdump(outgoing_pdu->data, outgoing_pdu->len);
287 #endif
288 
289     // crypto done
290     mesh_crypto_active = 0;
291 
292     // done
293     mesh_network_pdu_t * network_pdu = outgoing_pdu;
294     outgoing_pdu = NULL;
295     (network_pdu->callback)(network_pdu);
296 }
297 
298 static void mesh_network_send_b(void *arg){
299     UNUSED(arg);
300 
301     uint32_t iv_index = mesh_get_iv_index_for_tx();
302 
303     // store NetMIC
304     uint8_t net_mic[8];
305     btstack_crypto_ccm_get_authentication_value(&mesh_network_crypto_request.ccm, net_mic);
306 
307     // store MIC
308     uint8_t net_mic_len = outgoing_pdu->data[1] & 0x80 ? 8 : 4;
309     memcpy(&outgoing_pdu->data[outgoing_pdu->len], net_mic, net_mic_len);
310     outgoing_pdu->len += net_mic_len;
311 
312 #ifdef LOG_NETWORK
313     printf("TX-B-NetworkPDU (%p): ", outgoing_pdu);
314     printf_hexdump(outgoing_pdu->data, outgoing_pdu->len);
315 #endif
316 
317     // calc PECB
318     memset(encryption_block, 0, 5);
319     big_endian_store_32(encryption_block, 5, iv_index);
320     memcpy(&encryption_block[9], &outgoing_pdu->data[7], 7);
321     btstack_crypto_aes128_encrypt(&mesh_network_crypto_request.aes128, current_network_key->privacy_key, encryption_block, obfuscation_block, &mesh_network_send_c, NULL);
322 }
323 
324 static void mesh_network_send_a(void){
325 
326     mesh_crypto_active = 1;
327 
328     uint32_t iv_index = mesh_get_iv_index_for_tx();
329 
330     // lookup subnet by netkey_index
331     mesh_subnet_t * subnet = mesh_subnet_get_by_netkey_index(outgoing_pdu->netkey_index);
332     if (!subnet) {
333         mesh_crypto_active = 0;
334         // notify upper layer
335         mesh_network_pdu_t * network_pdu = outgoing_pdu;
336         outgoing_pdu = NULL;
337         (*mesh_network_higher_layer_handler)(MESH_NETWORK_PDU_SENT, network_pdu);
338         // run again
339         mesh_network_run();
340         return;
341     }
342 
343     // get network key to use for sending
344     current_network_key = mesh_subnet_get_outgoing_network_key(subnet);
345 
346 #ifdef LOG_NETWORK
347     printf("TX-A-NetworkPDU (%p): ", outgoing_pdu);
348     printf_hexdump(outgoing_pdu->data, outgoing_pdu->len);
349 #endif
350 
351     // get network nonce
352     if (outgoing_pdu->flags & MESH_NETWORK_PDU_FLAGS_PROXY_CONFIGURATION){
353         mesh_proxy_create_nonce(network_nonce, outgoing_pdu, iv_index);
354 #ifdef LOG_NETWORK
355         printf("TX-ProxyNonce:  ");
356         printf_hexdump(network_nonce, 13);
357 #endif
358     } else {
359         mesh_network_create_nonce(network_nonce, outgoing_pdu, iv_index);
360 #ifdef LOG_NETWORK
361         printf("TX-NetworkNonce:  ");
362         printf_hexdump(network_nonce, 13);
363 #endif
364     }
365 
366 #ifdef LOG_NETWORK
367    printf("TX-EncryptionKey: ");
368     printf_hexdump(current_network_key->encryption_key, 16);
369 #endif
370 
371     // start ccm
372     uint8_t cypher_len  = outgoing_pdu->len - 7;
373     uint8_t net_mic_len = outgoing_pdu->data[1] & 0x80 ? 8 : 4;
374     btstack_crypto_ccm_init(&mesh_network_crypto_request.ccm, current_network_key->encryption_key, network_nonce, cypher_len, 0, net_mic_len);
375     btstack_crypto_ccm_encrypt_block(&mesh_network_crypto_request.ccm, cypher_len, &outgoing_pdu->data[7], &outgoing_pdu->data[7], &mesh_network_send_b, NULL);
376 }
377 
378 #if defined(ENABLE_MESH_RELAY) || defined (ENABLE_MESH_PROXY_SERVER)
379 static void mesh_network_relay_message(mesh_network_pdu_t * network_pdu){
380 
381     uint8_t ctl_ttl     = network_pdu->data[1];
382     uint8_t ctl         = ctl_ttl & 0x80;
383     uint8_t ttl         = ctl_ttl & 0x7f;
384 
385 #ifdef LOG_NETWORK
386     printf("TX-Relay-NetworkPDU (%p): ", network_pdu);
387     printf_hexdump(network_pdu->data, network_pdu->len);
388     printf("^^ into network_pdus_queued\n");
389 #endif
390 
391     // prepare pdu for resending
392     network_pdu->data[1] = (ctl << 7) | (ttl - 1);
393     network_pdu->flags |= MESH_NETWORK_PDU_FLAGS_RELAY;
394 
395     // queue up
396     network_pdu->callback = &mesh_network_send_d;
397     btstack_linked_list_add_tail(&network_pdus_queued, (btstack_linked_item_t *) network_pdu);
398 }
399 #endif
400 
401 void mesh_network_message_processed_by_higher_layer(mesh_network_pdu_t * network_pdu){
402 
403 #if defined(ENABLE_MESH_RELAY) || defined (ENABLE_MESH_PROXY_SERVER)
404 
405     // check if address does not matches elements on our node and TTL >= 2
406     uint16_t src     = mesh_network_src(network_pdu);
407     uint8_t  ttl     = mesh_network_ttl(network_pdu);
408 
409     uint16_t mesh_network_primary_address = mesh_node_get_primary_element_address();
410 
411     if (((src < mesh_network_primary_address) || (src > (mesh_network_primary_address + mesh_node_element_count()))) && (ttl >= 2)){
412 
413         if ((network_pdu->flags & MESH_NETWORK_PDU_FLAGS_GATT_BEARER) == 0){
414 
415             // message received via ADV bearer are relayed:
416 
417 #ifdef ENABLE_MESH_RELAY
418             if (mesh_foundation_relay_get() != 0){
419                 // - to ADV bearer, if Relay supported and enabled
420                 mesh_network_relay_message(network_pdu);
421                 mesh_network_run();
422                 return;
423             }
424 #endif
425 
426 #ifdef ENABLE_MESH_PROXY_SERVER
427             if (mesh_foundation_gatt_proxy_get() != 0){
428                 // - to GATT bearer, if Proxy supported and enabled
429                 mesh_network_relay_message(network_pdu);
430                 mesh_network_run();
431                 return;
432             }
433 #endif
434 
435         } else {
436 
437             // messages received via GATT bearer are relayed:
438 
439 #ifdef ENABLE_MESH_PROXY_SERVER
440             if (mesh_foundation_gatt_proxy_get() != 0){
441                 // - to ADV bearer, if Proxy supported and enabled
442                 mesh_network_relay_message(network_pdu);
443                 mesh_network_run();
444                 return;
445             }
446 #endif
447 
448         }
449     }
450 #endif
451 
452     // otherwise, we're done
453     btstack_memory_mesh_network_pdu_free(network_pdu);
454 }
455 
456 static void process_network_pdu_done(void){
457     btstack_memory_mesh_network_pdu_free(incoming_pdu_raw);
458     incoming_pdu_raw = NULL;
459     mesh_crypto_active = 0;
460 
461     mesh_network_run();
462 }
463 
464 static void process_network_pdu_validate_d(void * arg){
465     UNUSED(arg);
466     // mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) arg;
467 
468     uint8_t ctl_ttl     = incoming_pdu_decoded->data[1];
469     uint8_t ctl         = ctl_ttl >> 7;
470     uint8_t net_mic_len = (ctl_ttl & 0x80) ? 8 : 4;
471 
472     // store NetMIC
473     uint8_t net_mic[8];
474     btstack_crypto_ccm_get_authentication_value(&mesh_network_crypto_request.ccm, net_mic);
475 #ifdef LOG_NETWORK
476     printf("RX-NetMIC: ");
477     printf_hexdump(net_mic, net_mic_len);
478 #endif
479     // store in decoded pdu
480     memcpy(&incoming_pdu_decoded->data[incoming_pdu_decoded->len-net_mic_len], net_mic, net_mic_len);
481 
482 #ifdef LOG_NETWORK
483     uint8_t cypher_len  = incoming_pdu_decoded->len - 9 - net_mic_len;
484     printf("RX-Decrypted DST/TransportPDU: ");
485     printf_hexdump(&incoming_pdu_decoded->data[7], 2 + cypher_len);
486 
487     printf("RX-Decrypted: ");
488     printf_hexdump(incoming_pdu_decoded->data, incoming_pdu_decoded->len);
489 #endif
490 
491     // validate network mic
492     if (memcmp(net_mic, &incoming_pdu_raw->data[incoming_pdu_decoded->len-net_mic_len], net_mic_len) != 0){
493         // fail
494         printf("RX-NetMIC mismatch, try next key\n");
495         process_network_pdu_validate();
496         return;
497     }
498 
499     // remove NetMIC from payload
500     incoming_pdu_decoded->len -= net_mic_len;
501 
502 #ifdef LOG_NETWORK
503     // match
504     printf("RX-NetMIC matches\n");
505     printf("RX-TTL: 0x%02x\n", incoming_pdu_decoded->data[1] & 0x7f);
506 #endif
507 
508     // set netkey_index
509     incoming_pdu_decoded->netkey_index = current_network_key->netkey_index;
510 
511     if (incoming_pdu_decoded->flags & MESH_NETWORK_PDU_FLAGS_PROXY_CONFIGURATION){
512 
513         mesh_network_pdu_t * decoded_pdu = incoming_pdu_decoded;
514         incoming_pdu_decoded = NULL;
515 
516         // no additional checks for proxy messages
517         (*mesh_network_proxy_message_handler)(MESH_NETWORK_PDU_RECEIVED, decoded_pdu);
518 
519     } else {
520 
521         // validate src/dest addresses
522         uint16_t src = big_endian_read_16(incoming_pdu_decoded->data, 5);
523         uint16_t dst = big_endian_read_16(incoming_pdu_decoded->data, 7);
524         int valid = mesh_network_addresses_valid(ctl, src, dst);
525         if (!valid){
526             printf("RX Address invalid\n");
527             btstack_memory_mesh_network_pdu_free(incoming_pdu_decoded);
528             incoming_pdu_decoded = NULL;
529             process_network_pdu_done();
530             return;
531         }
532 
533         // check cache
534         uint32_t hash = mesh_network_cache_hash(incoming_pdu_decoded);
535 #ifdef LOG_NETWORK
536         printf("RX-Hash: %08x\n", hash);
537 #endif
538         if (mesh_network_cache_find(hash)){
539             // found in cache, drop
540             printf("Found in cache -> drop packet\n");
541             btstack_memory_mesh_network_pdu_free(incoming_pdu_decoded);
542             incoming_pdu_decoded = NULL;
543             process_network_pdu_done();
544             return;
545         }
546 
547         // store in network cache
548         mesh_network_cache_add(hash);
549 
550         // forward to lower transport layer. message is freed by call to mesh_network_message_processed_by_upper_layer
551         mesh_network_pdu_t * decoded_pdu = incoming_pdu_decoded;
552         incoming_pdu_decoded = NULL;
553         (*mesh_network_higher_layer_handler)(MESH_NETWORK_PDU_RECEIVED, decoded_pdu);
554     }
555 
556     // done
557     process_network_pdu_done();
558 }
559 
560 static uint32_t iv_index_for_pdu(const mesh_network_pdu_t * network_pdu){
561     // get IV Index and IVI
562     uint32_t iv_index = mesh_get_iv_index();
563     int ivi = network_pdu->data[0] >> 7;
564 
565     // if least significant bit differs, use previous IV Index
566     if ((iv_index & 1 ) ^ ivi){
567         iv_index--;
568 #ifdef LOG_NETWORK
569         printf("RX-IV: IVI indicates previous IV index, using 0x%08x\n", iv_index);
570 #endif
571     }
572     return iv_index;
573 }
574 
575 static void process_network_pdu_validate_b(void * arg){
576     UNUSED(arg);
577 
578 #ifdef LOG_NETWORK
579     printf("RX-PECB: ");
580     printf_hexdump(obfuscation_block, 6);
581 #endif
582 
583     // de-obfuscate
584     unsigned int i;
585     for (i=0;i<6;i++){
586         incoming_pdu_decoded->data[1+i] = incoming_pdu_raw->data[1+i] ^ obfuscation_block[i];
587     }
588 
589     uint32_t iv_index = iv_index_for_pdu(incoming_pdu_raw);
590 
591     if (incoming_pdu_decoded->flags & MESH_NETWORK_PDU_FLAGS_PROXY_CONFIGURATION){
592         // create network nonce
593         mesh_proxy_create_nonce(network_nonce, incoming_pdu_decoded, iv_index);
594 #ifdef LOG_NETWORK
595         printf("RX-Proxy Nonce: ");
596         printf_hexdump(network_nonce, 13);
597 #endif
598     } else {
599         // create network nonce
600         mesh_network_create_nonce(network_nonce, incoming_pdu_decoded, iv_index);
601 #ifdef LOG_NETWORK
602         printf("RX-Network Nonce: ");
603         printf_hexdump(network_nonce, 13);
604 #endif
605     }
606 
607     //
608     uint8_t ctl_ttl     = incoming_pdu_decoded->data[1];
609     uint8_t net_mic_len = (ctl_ttl & 0x80) ? 8 : 4;
610     uint8_t cypher_len  = incoming_pdu_decoded->len - 7 - net_mic_len;
611 
612 #ifdef LOG_NETWORK
613     printf("RX-Cyper len %u, mic len %u\n", cypher_len, net_mic_len);
614 
615     printf("RX-Encryption Key: ");
616     printf_hexdump(current_network_key->encryption_key, 16);
617 
618 #endif
619 
620     btstack_crypto_ccm_init(&mesh_network_crypto_request.ccm, current_network_key->encryption_key, network_nonce, cypher_len, 0, net_mic_len);
621     btstack_crypto_ccm_decrypt_block(&mesh_network_crypto_request.ccm, cypher_len, &incoming_pdu_raw->data[7], &incoming_pdu_decoded->data[7], &process_network_pdu_validate_d, incoming_pdu_decoded);
622 }
623 
624 static void process_network_pdu_validate(void){
625     if (!mesh_network_key_nid_iterator_has_more(&validation_network_key_it)){
626         printf("No valid network key found\n");
627         btstack_memory_mesh_network_pdu_free(incoming_pdu_decoded);
628         incoming_pdu_decoded = NULL;
629         process_network_pdu_done();
630         return;
631     }
632 
633     current_network_key = mesh_network_key_nid_iterator_get_next(&validation_network_key_it);
634 
635     // calc PECB
636     uint32_t iv_index = iv_index_for_pdu(incoming_pdu_raw);
637     memset(encryption_block, 0, 5);
638     big_endian_store_32(encryption_block, 5, iv_index);
639     memcpy(&encryption_block[9], &incoming_pdu_raw->data[7], 7);
640     btstack_crypto_aes128_encrypt(&mesh_network_crypto_request.aes128, current_network_key->privacy_key, encryption_block, obfuscation_block, &process_network_pdu_validate_b, NULL);
641 }
642 
643 
644 static void process_network_pdu(void){
645     //
646     uint8_t nid_ivi = incoming_pdu_raw->data[0];
647 
648     // setup pdu object
649     incoming_pdu_decoded->data[0] = nid_ivi;
650     incoming_pdu_decoded->len     = incoming_pdu_raw->len;
651     incoming_pdu_decoded->flags   = incoming_pdu_raw->flags;
652 
653     // init provisioning data iterator
654     uint8_t nid = nid_ivi & 0x7f;
655     // uint8_t iv_index = network_pdu_data[0] >> 7;
656     mesh_network_key_nid_iterator_init(&validation_network_key_it, nid);
657 
658     process_network_pdu_validate();
659 }
660 
661 static void mesh_network_run(void){
662     if (!btstack_linked_list_empty(&network_pdus_outgoing_gatt)){
663 
664 
665 #ifdef ENABLE_MESH_GATT_BEARER
666         if (gatt_bearer_network_pdu == NULL){
667             // move to 'gatt bearer queue'
668             mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_outgoing_gatt);
669 
670 #ifdef LOG_NETWORK
671         printf("network run: pop %p from network_pdus_outgoing_gatt\n", network_pdu);
672 #endif
673         // request to send via gatt if:
674         // proxy active and connected
675         // packet wasn't received via gatt bearer
676             int send_via_gatt = ((mesh_foundation_gatt_proxy_get() != 0) &&
677             (gatt_bearer_con_handle != HCI_CON_HANDLE_INVALID) &&
678                                  ((network_pdu->flags & MESH_NETWORK_PDU_FLAGS_GATT_BEARER) == 0));
679             if (send_via_gatt){
680 #ifdef LOG_NETWORK
681         printf("network run: set %p as gatt_bearer_network_pdu\n", network_pdu);
682 #endif
683 
684                gatt_bearer_network_pdu = network_pdu;
685                 gatt_bearer_request_can_send_now_for_network_pdu();
686             } else {
687 #ifdef LOG_NETWORK
688         printf("network run: push %p to network_pdus_outgoing_adv\n", network_pdu);
689 #endif
690                 btstack_linked_list_add_tail(&network_pdus_outgoing_adv, (btstack_linked_item_t *) network_pdu);
691             }
692         }
693 #else
694         // directly move to 'outgoing adv bearer queue'
695         mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_outgoing_gatt);
696         btstack_linked_list_add_tail(&network_pdus_outgoing_adv, (btstack_linked_item_t *) network_pdu);
697 #endif
698     }
699 
700     if (!btstack_linked_list_empty(&network_pdus_outgoing_adv)){
701 #ifdef ENABLE_MESH_ADV_BEARER
702         if (adv_bearer_network_pdu == NULL){
703             // move to 'adv bearer queue'
704 #ifdef LOG_NETWORK
705             mesh_network_dump_network_pdus("network_pdus_outgoing_adv", &network_pdus_outgoing_adv);
706 #endif
707             mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_outgoing_adv);
708 #ifdef LOG_NETWORK
709             printf("network run: pop %p from network_pdus_outgoing_adv\n", network_pdu);
710             mesh_network_dump_network_pdus("network_pdus_outgoing_adv", &network_pdus_outgoing_adv);
711 #endif
712             adv_bearer_network_pdu = network_pdu;
713             adv_bearer_request_can_send_now_for_network_pdu();
714         }
715 #else
716         // done
717         mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_outgoing_adv);
718         // directly notify upper layer
719         (*mesh_network_higher_layer_handler)(MESH_NETWORK_PDU_SENT, network_pdu);
720 #endif
721     }
722 
723     if (mesh_crypto_active) return;
724 
725     if (!btstack_linked_list_empty(&network_pdus_received)){
726         incoming_pdu_decoded = mesh_network_pdu_get();
727         if (!incoming_pdu_decoded) return;
728         // get encoded network pdu and start processing
729         mesh_crypto_active = 1;
730         incoming_pdu_raw = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_received);
731         process_network_pdu();
732         return;
733     }
734 
735     if (!btstack_linked_list_empty(&network_pdus_queued)){
736         // get queued network pdu and start processing
737 #ifdef LOG_NETWORK
738         mesh_network_dump_network_pdus("network_pdus_queued", &network_pdus_queued);
739 #endif
740         outgoing_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&network_pdus_queued);
741 #ifdef LOG_NETWORK
742         printf("network run: pop %p from network_pdus_queued\n", outgoing_pdu);
743         mesh_network_dump_network_pdus("network_pdus_queued", &network_pdus_queued);
744 #endif
745         mesh_network_send_a();
746         return;
747     }
748 }
749 
750 #ifdef ENABLE_MESH_ADV_BEARER
751 static void mesh_adv_bearer_handle_network_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
752     UNUSED(channel);
753     mesh_network_pdu_t * network_pdu;
754     uint8_t  transmission_count;
755     uint16_t transmission_interval;
756     uint8_t  transmit_config;
757 
758     switch (packet_type){
759         case MESH_NETWORK_PACKET:
760             // check len. minimal transport PDU len = 1, 32 bit NetMIC -> 13 bytes
761             if (size < 13) break;
762 
763 #ifdef LOG_NETWORK
764             printf("received network pdu from adv (len %u): ", size);
765             printf_hexdump(packet, size);
766 #endif
767             mesh_network_received_message(packet, size, 0);
768             break;
769 
770         case HCI_EVENT_PACKET:
771             switch(packet[0]){
772                 case HCI_EVENT_MESH_META:
773                     switch(packet[2]){
774                         case MESH_SUBEVENT_CAN_SEND_NOW:
775                             if (adv_bearer_network_pdu == NULL) break;
776 
777                             // Get Transmission config depending on relay flag
778                             if (adv_bearer_network_pdu->flags & MESH_NETWORK_PDU_FLAGS_RELAY){
779                                 transmit_config = mesh_foundation_relay_get();
780                             } else {
781                                 transmit_config = mesh_foundation_network_transmit_get();
782                             }
783                             transmission_count     = (transmit_config & 0x07) + 1;
784                             transmission_interval = (transmit_config >> 3) * 10;
785 
786 #ifdef LOG_NETWORK
787                             printf("TX-E-NetworkPDU count %u, interval %u ms (%p): ", transmission_count, transmission_interval, adv_bearer_network_pdu);
788                             printf_hexdump(adv_bearer_network_pdu->data, adv_bearer_network_pdu->len);
789 #endif
790 
791                             adv_bearer_send_network_pdu(adv_bearer_network_pdu->data, adv_bearer_network_pdu->len, transmission_count, transmission_interval);
792                             network_pdu = adv_bearer_network_pdu;
793                             adv_bearer_network_pdu = NULL;
794 
795                             // notify upper layer
796                             (*mesh_network_higher_layer_handler)(MESH_NETWORK_PDU_SENT, network_pdu);
797 
798                             // check if more to send
799                             mesh_network_run();
800                             break;
801                         default:
802                             break;
803                     }
804                     break;
805                 default:
806                     break;
807             }
808             break;
809     }
810 }
811 #endif
812 
813 #ifdef ENABLE_MESH_GATT_BEARER
814 static void mesh_network_gatt_bearer_outgoing_complete(void){
815 
816     if (gatt_bearer_network_pdu == NULL) return;
817 
818     // forward to adv bearer
819     btstack_linked_list_add_tail(&network_pdus_outgoing_adv, (btstack_linked_item_t*) gatt_bearer_network_pdu);
820     gatt_bearer_network_pdu = NULL;
821 
822     mesh_network_run();
823     return;
824 }
825 
826 static void mesh_network_gatt_bearer_handle_network_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
827     UNUSED(channel);
828     switch (packet_type){
829         case MESH_PROXY_DATA_PACKET:
830             if (mesh_foundation_gatt_proxy_get() == 0) break;
831 #ifdef LOG_NETWORK
832             printf("received network pdu from gatt (len %u): ", size);
833             printf_hexdump(packet, size);
834 #endif
835             mesh_network_received_message(packet, size, MESH_NETWORK_PDU_FLAGS_GATT_BEARER);
836             break;
837         case HCI_EVENT_PACKET:
838             switch (hci_event_packet_get_type(packet)){
839                 case HCI_EVENT_MESH_META:
840                     switch (hci_event_mesh_meta_get_subevent_code(packet)){
841                         case MESH_SUBEVENT_PROXY_CONNECTED:
842                             gatt_bearer_con_handle = mesh_subevent_proxy_connected_get_con_handle(packet);
843                             break;
844                         case MESH_SUBEVENT_PROXY_DISCONNECTED:
845                             gatt_bearer_con_handle = HCI_CON_HANDLE_INVALID;
846                             mesh_network_gatt_bearer_outgoing_complete();
847                             break;
848                         case MESH_SUBEVENT_CAN_SEND_NOW:
849                             if (gatt_bearer_network_pdu == NULL) break;
850 #ifdef LOG_NETWORK
851                             printf("G-TX-E-NetworkPDU (%p): ", gatt_bearer_network_pdu);
852                             printf_hexdump(gatt_bearer_network_pdu->data, gatt_bearer_network_pdu->len);
853 #endif
854                             gatt_bearer_send_network_pdu(gatt_bearer_network_pdu->data, gatt_bearer_network_pdu->len);
855                             break;
856 
857                         case MESH_SUBEVENT_MESSAGE_SENT:
858                             mesh_network_gatt_bearer_outgoing_complete();
859                             break;
860                         default:
861                             break;
862                     }
863                     break;
864                 default:
865                     break;
866             }
867             break;
868         default:
869             break;
870     }
871 }
872 #endif
873 
874 #ifdef ENABLE_MESH_GATT_BEARER
875 static void mesh_netework_gatt_bearer_handle_proxy_configuration(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
876     UNUSED(channel);
877     switch (packet_type){
878         case MESH_PROXY_DATA_PACKET:
879             mesh_network_process_proxy_configuration_message(packet, size);
880             break;
881         case HCI_EVENT_PACKET:
882             switch (hci_event_packet_get_type(packet)){
883                 case HCI_EVENT_MESH_META:
884                     switch (hci_event_mesh_meta_get_subevent_code(packet)){
885                         case MESH_SUBEVENT_CAN_SEND_NOW:
886                             // forward to higher layer
887                             (*mesh_network_proxy_message_handler)(MESH_NETWORK_CAN_SEND_NOW, NULL);
888                             break;
889                         default:
890                             break;
891                     }
892                     break;
893                 default:
894                     break;
895             }
896             break;
897         default:
898             break;
899     }
900 }
901 #endif
902 
903 void mesh_network_init(void){
904 #ifdef ENABLE_MESH_ADV_BEARER
905     adv_bearer_register_for_network_pdu(&mesh_adv_bearer_handle_network_event);
906 #endif
907 #ifdef ENABLE_MESH_GATT_BEARER
908     gatt_bearer_con_handle = HCI_CON_HANDLE_INVALID;
909     gatt_bearer_register_for_network_pdu(&mesh_network_gatt_bearer_handle_network_event);
910     gatt_bearer_register_for_mesh_proxy_configuration(&mesh_netework_gatt_bearer_handle_proxy_configuration);
911 #endif
912 }
913 
914 void mesh_network_set_higher_layer_handler(void (*packet_handler)(mesh_network_callback_type_t callback_type, mesh_network_pdu_t * network_pdu)){
915     mesh_network_higher_layer_handler = packet_handler;
916 }
917 
918 void mesh_network_set_proxy_message_handler(void (*packet_handler)(mesh_network_callback_type_t callback_type, mesh_network_pdu_t * network_pdu)){
919     mesh_network_proxy_message_handler = packet_handler;
920 }
921 
922 void mesh_network_received_message(const uint8_t * pdu_data, uint8_t pdu_len, uint8_t flags){
923     // verify len
924     if (pdu_len > 29) return;
925 
926     // allocate network_pdu
927     mesh_network_pdu_t * network_pdu = mesh_network_pdu_get();
928     if (!network_pdu) return;
929 
930     // store data
931     memcpy(network_pdu->data, pdu_data, pdu_len);
932     network_pdu->len = pdu_len;
933     network_pdu->flags = flags;
934 
935     // add to list and go
936     btstack_linked_list_add_tail(&network_pdus_received, (btstack_linked_item_t *) network_pdu);
937     mesh_network_run();
938 
939 }
940 
941 void mesh_network_process_proxy_configuration_message(const uint8_t * pdu_data, uint8_t pdu_len){
942     // verify len
943     if (pdu_len > 29) return;
944 
945     // allocate network_pdu
946     mesh_network_pdu_t * network_pdu = mesh_network_pdu_get();
947     if (!network_pdu) return;
948 
949     // store data
950     memcpy(network_pdu->data, pdu_data, pdu_len);
951     network_pdu->len = pdu_len;
952     network_pdu->flags = MESH_NETWORK_PDU_FLAGS_PROXY_CONFIGURATION; // Network PDU
953 
954     // add to list and go
955     btstack_linked_list_add_tail(&network_pdus_received, (btstack_linked_item_t *) network_pdu);
956     mesh_network_run();
957 }
958 
959 void mesh_network_send_pdu(mesh_network_pdu_t * network_pdu){
960 #ifdef LOG_NETWORK
961     printf("TX-NetworkPDU (%p):   ", network_pdu);
962     printf_hexdump(network_pdu->data, network_pdu->len);
963     printf("^^ into network_pdus_queued\n");
964 #endif
965 
966     if (network_pdu->len > 29){
967         printf("too long, %u\n", network_pdu->len);
968         while(1);
969     }
970 
971     // network pdu without payload and minimal mic = 13 bytes
972     if (network_pdu->len <13){
973         printf("too short, %u\n", network_pdu->len);
974         while(1);
975     }
976 
977     // setup callback
978     network_pdu->callback = &mesh_network_send_d;
979     network_pdu->flags    = 0;
980 
981     // queue up
982     btstack_linked_list_add_tail(&network_pdus_queued, (btstack_linked_item_t *) network_pdu);
983 #ifdef LOG_NETWORK
984     mesh_network_dump_network_pdus("network_pdus_queued", &network_pdus_queued);
985 #endif
986 
987     // go
988     mesh_network_run();
989 }
990 
991 void mesh_network_encrypt_proxy_configuration_message(mesh_network_pdu_t * network_pdu, void (* callback)(mesh_network_pdu_t * callback)){
992     printf("ProxyPDU(unencrypted): ");
993     printf_hexdump(network_pdu->data, network_pdu->len);
994 
995     // setup callback
996     network_pdu->callback = callback;
997     network_pdu->flags    = MESH_NETWORK_PDU_FLAGS_PROXY_CONFIGURATION;
998 
999     // queue up
1000     btstack_linked_list_add_tail(&network_pdus_queued, (btstack_linked_item_t *) network_pdu);
1001 
1002     // go
1003     mesh_network_run();
1004 }
1005 
1006 /*
1007  * @brief Setup network pdu header
1008  * @param netkey_index
1009  * @param ctl
1010  * @param ttl
1011  * @param seq
1012  * @param dest
1013  */
1014 void mesh_network_setup_pdu(mesh_network_pdu_t * network_pdu, uint16_t netkey_index, uint8_t nid, uint8_t ctl, uint8_t ttl, uint32_t seq, uint16_t src, uint16_t dest, const uint8_t * transport_pdu_data, uint8_t transport_pdu_len){
1015     memset(network_pdu, 0, sizeof(mesh_network_pdu_t));
1016     // set netkey_index
1017     network_pdu->netkey_index = netkey_index;
1018     // setup header
1019     network_pdu->data[network_pdu->len++] = (mesh_get_iv_index_for_tx() << 7) |  nid;
1020     uint8_t ctl_ttl = (ctl << 7) | (ttl & 0x7f);
1021     network_pdu->data[network_pdu->len++] = ctl_ttl;
1022     big_endian_store_24(network_pdu->data, 2, seq);
1023     network_pdu->len += 3;
1024     big_endian_store_16(network_pdu->data, network_pdu->len, src);
1025     network_pdu->len += 2;
1026     big_endian_store_16(network_pdu->data, network_pdu->len, dest);
1027     network_pdu->len += 2;
1028     memcpy(&network_pdu->data[network_pdu->len], transport_pdu_data, transport_pdu_len);
1029     network_pdu->len += transport_pdu_len;
1030 }
1031 
1032 /*
1033  * @brief Setup network pdu header
1034  * @param netkey_index
1035  * @param ctl
1036  * @param ttl
1037  * @param seq
1038  * @param dest
1039  */
1040 void mesh_network_setup_pdu_header(mesh_network_pdu_t * network_pdu, uint16_t netkey_index, uint8_t nid, uint8_t ctl, uint8_t ttl, uint32_t seq, uint16_t src, uint16_t dest){
1041     // set netkey_index
1042     network_pdu->netkey_index = netkey_index;
1043     // setup header
1044     network_pdu->data[0] = (mesh_get_iv_index_for_tx() << 7) |  nid;
1045     uint8_t ctl_ttl = (ctl << 7) | (ttl & 0x7f);
1046     network_pdu->data[1] = ctl_ttl;
1047     big_endian_store_24(network_pdu->data, 2, seq);
1048     big_endian_store_16(network_pdu->data, 5, src);
1049     big_endian_store_16(network_pdu->data, 7, dest);
1050 }
1051 
1052 // Network PDU Getter
1053 uint8_t  mesh_network_nid(mesh_network_pdu_t * network_pdu){
1054     return network_pdu->data[0] & 0x7f;
1055 }
1056 uint16_t mesh_network_control(mesh_network_pdu_t * network_pdu){
1057     return network_pdu->data[1] & 0x80;
1058 }
1059 uint8_t mesh_network_ttl(mesh_network_pdu_t * network_pdu){
1060     return network_pdu->data[1] & 0x7f;
1061 }
1062 uint32_t mesh_network_seq(mesh_network_pdu_t * network_pdu){
1063     return big_endian_read_24(network_pdu->data, 2);
1064 }
1065 uint16_t mesh_network_src(mesh_network_pdu_t * network_pdu){
1066     return big_endian_read_16(network_pdu->data, 5);
1067 }
1068 uint16_t mesh_network_dst(mesh_network_pdu_t * network_pdu){
1069     return big_endian_read_16(network_pdu->data, 7);
1070 }
1071 int mesh_network_segmented(mesh_network_pdu_t * network_pdu){
1072     return network_pdu->data[9] & 0x80;
1073 }
1074 uint8_t mesh_network_control_opcode(mesh_network_pdu_t * network_pdu){
1075     return network_pdu->data[9] & 0x7f;
1076 }
1077 uint8_t * mesh_network_pdu_data(mesh_network_pdu_t * network_pdu){
1078     return &network_pdu->data[9];
1079 }
1080 uint8_t   mesh_network_pdu_len(mesh_network_pdu_t * network_pdu){
1081     return network_pdu->len - 9;
1082 }
1083 
1084 static void mesh_network_dump_network_pdu(mesh_network_pdu_t * network_pdu){
1085     if (network_pdu){
1086         printf("- %p: ", network_pdu); printf_hexdump(network_pdu->data, network_pdu->len);
1087     }
1088 }
1089 static void mesh_network_dump_network_pdus(const char * name, btstack_linked_list_t * list){
1090     printf("List: %s:\n", name);
1091     btstack_linked_list_iterator_t it;
1092     btstack_linked_list_iterator_init(&it, list);
1093     while (btstack_linked_list_iterator_has_next(&it)){
1094         mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t*) btstack_linked_list_iterator_next(&it);
1095         mesh_network_dump_network_pdu(network_pdu);
1096     }
1097 }
1098 static void mesh_network_reset_network_pdus(btstack_linked_list_t * list){
1099     while (!btstack_linked_list_empty(list)){
1100         mesh_network_pdu_t * pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(list);
1101         btstack_memory_mesh_network_pdu_free(pdu);
1102     }
1103 }
1104 void mesh_network_dump(void){
1105     mesh_network_dump_network_pdus("network_pdus_received", &network_pdus_received);
1106     mesh_network_dump_network_pdus("network_pdus_queued", &network_pdus_queued);
1107     mesh_network_dump_network_pdus("network_pdus_outgoing_gatt", &network_pdus_outgoing_gatt);
1108     mesh_network_dump_network_pdus("network_pdus_outgoing_adv", &network_pdus_outgoing_adv);
1109     printf("outgoing_pdu: \n");
1110     mesh_network_dump_network_pdu(outgoing_pdu);
1111     printf("incoming_pdu_raw: \n");
1112     mesh_network_dump_network_pdu(incoming_pdu_raw);
1113     printf("gatt_bearer_network_pdu: \n");
1114     mesh_network_dump_network_pdu(gatt_bearer_network_pdu);
1115     printf("adv_bearer_network_pdu: \n");
1116     mesh_network_dump_network_pdu(adv_bearer_network_pdu);
1117 }
1118 void mesh_network_reset(void){
1119     mesh_network_reset_network_pdus(&network_pdus_received);
1120     mesh_network_reset_network_pdus(&network_pdus_queued);
1121     mesh_network_reset_network_pdus(&network_pdus_outgoing_gatt);
1122     mesh_network_reset_network_pdus(&network_pdus_outgoing_adv);
1123     if (adv_bearer_network_pdu){
1124         mesh_network_pdu_free(adv_bearer_network_pdu);
1125         adv_bearer_network_pdu = NULL;
1126     }
1127     if (gatt_bearer_network_pdu){
1128         mesh_network_pdu_free(gatt_bearer_network_pdu);
1129         gatt_bearer_network_pdu = NULL;
1130     }
1131     if (outgoing_pdu){
1132         mesh_network_pdu_free(outgoing_pdu);
1133         outgoing_pdu = NULL;
1134     }
1135     if (incoming_pdu_raw){
1136         mesh_network_pdu_free(incoming_pdu_raw);
1137         incoming_pdu_raw = NULL;
1138     }
1139     if (incoming_pdu_decoded){
1140         mesh_network_pdu_free(incoming_pdu_decoded);
1141         incoming_pdu_decoded = NULL;
1142     }
1143     mesh_crypto_active = 0;
1144 }
1145 
1146 // buffer pool
1147 mesh_network_pdu_t * mesh_network_pdu_get(void){
1148     mesh_network_pdu_t * network_pdu = btstack_memory_mesh_network_pdu_get();
1149     if (network_pdu) {
1150         memset(network_pdu, 0, sizeof(mesh_network_pdu_t));
1151         network_pdu->pdu_header.pdu_type = MESH_PDU_TYPE_NETWORK;
1152     }
1153     return network_pdu;
1154 }
1155 
1156 void mesh_network_pdu_free(mesh_network_pdu_t * network_pdu){
1157     btstack_memory_mesh_network_pdu_free(network_pdu);
1158 }
1159 
1160 // Mesh Subnet Management
1161 
1162 void mesh_subnet_add(mesh_subnet_t * subnet){
1163     btstack_linked_list_add_tail(&subnets, (btstack_linked_item_t *) subnet);
1164 }
1165 
1166 void mesh_subnet_remove(mesh_subnet_t * subnet){
1167     btstack_linked_list_remove(&subnets, (btstack_linked_item_t *) subnet);
1168 }
1169 
1170 mesh_subnet_t * mesh_subnet_get_by_netkey_index(uint16_t netkey_index){
1171     btstack_linked_list_iterator_t it;
1172     btstack_linked_list_iterator_init(&it, &subnets);
1173     while (btstack_linked_list_iterator_has_next(&it)){
1174         mesh_subnet_t * item = (mesh_subnet_t *) btstack_linked_list_iterator_next(&it);
1175         if (item->netkey_index == netkey_index) return item;
1176     }
1177     return NULL;
1178 }
1179 
1180 int mesh_subnet_list_count(void){
1181     return btstack_linked_list_count(&subnets);
1182 }
1183 
1184 // mesh network key iterator over all keys
1185 void mesh_subnet_iterator_init(mesh_subnet_iterator_t *it){
1186     btstack_linked_list_iterator_init(&it->it, &subnets);
1187 }
1188 
1189 int mesh_subnet_iterator_has_more(mesh_subnet_iterator_t *it){
1190     return btstack_linked_list_iterator_has_next(&it->it);
1191 }
1192 
1193 mesh_subnet_t * mesh_subnet_iterator_get_next(mesh_subnet_iterator_t *it){
1194     return (mesh_subnet_t *) btstack_linked_list_iterator_next(&it->it);
1195 }
1196 
1197 mesh_network_key_t * mesh_subnet_get_outgoing_network_key(mesh_subnet_t * subnet){
1198     switch (subnet->key_refresh){
1199         case MESH_KEY_REFRESH_SECOND_PHASE:
1200             return subnet->new_key;
1201         case MESH_KEY_REFRESH_NOT_ACTIVE:
1202         case MESH_KEY_REFRESH_FIRST_PHASE:
1203         default:
1204             return subnet->old_key;
1205     }
1206 }
1207 
1208 /**
1209  * @brief Setup subnet for given netkey index
1210  */
1211 void mesh_subnet_setup_for_netkey_index(uint16_t netkey_index){
1212     mesh_subnet_t * subnet = mesh_subnet_get_by_netkey_index(netkey_index);
1213     if (subnet != NULL) return;
1214 
1215     // find old / new keys
1216     mesh_network_key_t * old_key = NULL;
1217     mesh_network_key_t * new_key = NULL;
1218     mesh_network_key_iterator_t it;
1219     mesh_network_key_iterator_init(&it);
1220     while (mesh_network_key_iterator_has_more(&it)){
1221         mesh_network_key_t * network_key = mesh_network_key_iterator_get_next(&it);
1222         if (network_key->netkey_index != netkey_index) continue;
1223         if (old_key == NULL){
1224             old_key = network_key;
1225             continue;
1226         }
1227         // assign current key depending on key version
1228         if (((int8_t) (network_key->version - new_key->version)) > 0) {
1229             new_key = network_key;
1230         } else {
1231             new_key = old_key;
1232             old_key = network_key;
1233         }
1234     }
1235 
1236     // create subnet for netkey index
1237     subnet = btstack_memory_mesh_subnet_get();
1238     if (subnet == NULL) return;
1239     subnet->netkey_index = netkey_index;
1240     mesh_subnet_add(subnet);
1241 
1242     // set keys
1243     subnet->old_key = old_key;
1244     subnet->new_key = new_key;
1245 
1246     // key refresh
1247     if (new_key == NULL){
1248         // single key -> key refresh not active
1249         subnet->key_refresh = MESH_KEY_REFRESH_NOT_ACTIVE;
1250     }
1251     else {
1252         // two keys -> at least phase 1
1253         subnet->key_refresh = MESH_KEY_REFRESH_FIRST_PHASE;
1254     }
1255 }
1256