xref: /btstack/src/mesh/mesh_upper_transport.c (revision 12ba52abb7b659fe3c845a2e8fee70e87219d4d0)
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__ "mesh_upper_transport.c"
39 
40 #include "mesh/mesh_upper_transport.h"
41 
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 
46 #include "btstack_util.h"
47 #include "btstack_memory.h"
48 #include "btstack_debug.h"
49 
50 #include "mesh/beacon.h"
51 #include "mesh/mesh_iv_index_seq_number.h"
52 #include "mesh/mesh_keys.h"
53 #include "mesh/mesh_lower_transport.h"
54 #include "mesh/mesh_peer.h"
55 #include "mesh/mesh_virtual_addresses.h"
56 
57 // TODO: extract mesh_pdu functions into lower transport or network
58 #include "mesh/mesh_access.h"
59 
60 // combined key x address iterator for upper transport decryption
61 
62 typedef struct {
63     // state
64     mesh_transport_key_iterator_t  key_it;
65     mesh_virtual_address_iterator_t address_it;
66     // elements
67     const mesh_transport_key_t *   key;
68     const mesh_virtual_address_t * address;
69     // address - might be virtual
70     uint16_t dst;
71     // key info
72 } mesh_transport_key_and_virtual_address_iterator_t;
73 
74 static void (*higher_layer_handler)( mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu);
75 
76 static void mesh_upper_transport_validate_unsegmented_message(void);
77 static void mesh_upper_transport_validate_segmented_message(void);
78 static void mesh_upper_transport_run(void);
79 
80 static int crypto_active;
81 
82 static mesh_unsegmented_incoming_pdu_t * incoming_unsegmented_pdu_raw;
83 static mesh_network_pdu_t   * incoming_network_pdu_decoded;
84 
85 static mesh_message_pdu_t     incoming_message_pdu_singleton;
86 
87 static mesh_access_pdu_t    * incoming_access_pdu_encrypted;
88 static mesh_access_pdu_t    * incoming_access_pdu_decrypted;
89 
90 static mesh_access_pdu_t      incoming_access_pdu_encrypted_singleton;
91 static mesh_access_pdu_t      incoming_access_pdu_decrypted_singleton;
92 
93 static mesh_message_pdu_t     outgoing_segmented_message_singleton;
94 
95 static uint8_t application_nonce[13];
96 static btstack_crypto_ccm_t ccm;
97 static mesh_transport_key_and_virtual_address_iterator_t mesh_transport_key_it;
98 
99 // upper transport callbacks - in access layer
100 static void (*mesh_access_message_handler)(mesh_pdu_t * pdu);
101 static void (*mesh_control_message_handler)(mesh_pdu_t * pdu);
102 
103 // incoming unsegmented (network) and segmented (transport) control and access messages
104 static btstack_linked_list_t upper_transport_incoming;
105 
106 // outgoing unsegmented (network) and segmented (uppert_transport_outgoing) control and access messages
107 static btstack_linked_list_t upper_transport_outgoing;
108 
109 
110 // TODO: higher layer define used for assert
111 #define MESH_ACCESS_OPCODE_NOT_SET 0xFFFFFFFEu
112 
113 void mesh_upper_transport_send_access_pdu(mesh_pdu_t *pdu){
114     btstack_assert(pdu->pdu_type != MESH_PDU_TYPE_NETWORK);
115 
116     btstack_linked_list_add_tail(&upper_transport_outgoing, (btstack_linked_item_t*) pdu);
117     mesh_upper_transport_run();
118 }
119 
120 void mesh_upper_transport_send_control_pdu(mesh_pdu_t * pdu){
121     if (pdu->pdu_type == MESH_PDU_TYPE_NETWORK){
122         btstack_assert( ((mesh_network_pdu_t *) pdu)->len >= 9);
123     }
124 
125     btstack_linked_list_add_tail(&upper_transport_outgoing, (btstack_linked_item_t*) pdu);
126     mesh_upper_transport_run();
127 }
128 
129 static void mesh_print_hex(const char * name, const uint8_t * data, uint16_t len){
130     printf("%-20s ", name);
131     printf_hexdump(data, len);
132 }
133 // static void mesh_print_x(const char * name, uint32_t value){
134 //     printf("%20s: 0x%x", name, (int) value);
135 // }
136 
137 static void mesh_transport_key_and_virtual_address_iterator_init(mesh_transport_key_and_virtual_address_iterator_t *it,
138                                                                  uint16_t dst, uint16_t netkey_index, uint8_t akf,
139                                                                  uint8_t aid) {
140     printf("KEY_INIT: dst %04x, akf %x, aid %x\n", dst, akf, aid);
141     // config
142     it->dst   = dst;
143     // init elements
144     it->key     = NULL;
145     it->address = NULL;
146     // init element iterators
147     mesh_transport_key_aid_iterator_init(&it->key_it, netkey_index, akf, aid);
148     // init address iterator
149     if (mesh_network_address_virtual(it->dst)){
150         mesh_virtual_address_iterator_init(&it->address_it, dst);
151         // get first key
152         if (mesh_transport_key_aid_iterator_has_more(&it->key_it)) {
153             it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
154         }
155     }
156 }
157 
158 // cartesian product: keys x addressses
159 static int mesh_transport_key_and_virtual_address_iterator_has_more(mesh_transport_key_and_virtual_address_iterator_t * it){
160     if (mesh_network_address_virtual(it->dst)) {
161         // find next valid entry
162         while (true){
163             if (mesh_virtual_address_iterator_has_more(&it->address_it)) return 1;
164             if (!mesh_transport_key_aid_iterator_has_more(&it->key_it)) return 0;
165             // get next key
166             it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
167             mesh_virtual_address_iterator_init(&it->address_it, it->dst);
168         }
169     } else {
170         return mesh_transport_key_aid_iterator_has_more(&it->key_it);
171     }
172 }
173 
174 static void mesh_transport_key_and_virtual_address_iterator_next(mesh_transport_key_and_virtual_address_iterator_t * it){
175     if (mesh_network_address_virtual(it->dst)) {
176         it->address = mesh_virtual_address_iterator_get_next(&it->address_it);
177     } else {
178         it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
179     }
180 }
181 
182 // UPPER TRANSPORT
183 
184 static uint16_t mesh_access_dst(mesh_access_pdu_t * access_pdu){
185     return big_endian_read_16(access_pdu->network_header, 7);
186 }
187 
188 uint16_t mesh_access_ctl(mesh_access_pdu_t * access_pdu){
189     return access_pdu->network_header[1] >> 7;
190 }
191 
192 
193 // stub lower transport
194 
195 static void mesh_upper_transport_dump_pdus(const char *name, btstack_linked_list_t *list){
196     printf("List: %s:\n", name);
197     btstack_linked_list_iterator_t it;
198     btstack_linked_list_iterator_init(&it, list);
199     while (btstack_linked_list_iterator_has_next(&it)){
200         mesh_pdu_t * pdu = (mesh_pdu_t*) btstack_linked_list_iterator_next(&it);
201         printf("- %p\n", pdu);
202         // printf_hexdump( mesh_pdu_data(pdu), mesh_pdu_len(pdu));
203     }
204 }
205 
206 static void mesh_upper_transport_reset_pdus(btstack_linked_list_t *list){
207     while (!btstack_linked_list_empty(list)){
208         mesh_upper_transport_pdu_free((mesh_pdu_t *) btstack_linked_list_pop(list));
209     }
210 }
211 
212 void mesh_upper_transport_dump(void){
213     printf("incoming_unsegmented_pdu_raw: %p\n", incoming_unsegmented_pdu_raw);
214     printf("incoming_network_pdu_decoded: %p\n", incoming_network_pdu_decoded);
215     mesh_upper_transport_dump_pdus("upper_transport_incoming", &upper_transport_incoming);
216 }
217 
218 void mesh_upper_transport_reset(void){
219     crypto_active = 0;
220     if (incoming_unsegmented_pdu_raw){
221         mesh_network_pdu_t * network_pdu = incoming_unsegmented_pdu_raw->segment;
222         btstack_assert(network_pdu != NULL);
223         incoming_unsegmented_pdu_raw->segment = NULL;
224         mesh_network_pdu_free(network_pdu);
225         incoming_unsegmented_pdu_raw = NULL;
226     }
227     mesh_upper_transport_reset_pdus(&upper_transport_incoming);
228 }
229 
230 static uint32_t iv_index_for_ivi_nid(uint8_t ivi_nid){
231     // get IV Index and IVI
232     uint32_t iv_index = mesh_get_iv_index();
233     int ivi = ivi_nid >> 7;
234 
235     // if least significant bit differs, use previous IV Index
236     if ((iv_index & 1 ) ^ ivi){
237         iv_index--;
238     }
239     return iv_index;
240 }
241 
242 static void transport_unsegmented_setup_nonce(uint8_t * nonce, const mesh_network_pdu_t * network_pdu){
243     nonce[1] = 0x00;    // SZMIC if a Segmented Access message or 0 for all other message formats
244     (void)memcpy(&nonce[2], &network_pdu->data[2], 7);
245     big_endian_store_32(nonce, 9, iv_index_for_ivi_nid(network_pdu->data[0]));
246 }
247 
248 static void transport_segmented_setup_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
249     mesh_transport_pdu_t * transport_pdu;
250     mesh_access_pdu_t * access_pdu;
251     switch (pdu->pdu_type){
252         case MESH_PDU_TYPE_TRANSPORT:
253             transport_pdu = (mesh_transport_pdu_t *) pdu;
254             nonce[1] = transport_pdu->transmic_len == 8 ? 0x80 : 0x00;
255             (void)memcpy(&nonce[2], &transport_pdu->network_header[2], 7);
256             big_endian_store_32(nonce, 9, iv_index_for_ivi_nid(transport_pdu->network_header[0]));
257             break;
258         case MESH_PDU_TYPE_ACCESS:
259             access_pdu = (mesh_access_pdu_t *) pdu;
260             nonce[1] = access_pdu->transmic_len == 8 ? 0x80 : 0x00;
261             (void)memcpy(&nonce[2], &access_pdu->network_header[2], 7);
262             big_endian_store_32(nonce, 9, iv_index_for_ivi_nid(access_pdu->network_header[0]));
263             break;
264         default:
265             btstack_assert(0);
266             break;
267     }
268 }
269 
270 static void transport_unsegmented_setup_application_nonce(uint8_t * nonce, const mesh_network_pdu_t * network_pdu){
271     nonce[0] = 0x01;
272     transport_unsegmented_setup_nonce(nonce, network_pdu);
273     mesh_print_hex("AppNonce", nonce, 13);
274 }
275 
276 static void transport_unsegmented_setup_device_nonce(uint8_t * nonce, const mesh_network_pdu_t * network_pdu){
277     nonce[0] = 0x02;
278     transport_unsegmented_setup_nonce(nonce, network_pdu);
279     mesh_print_hex("DeviceNonce", nonce, 13);
280 }
281 
282 static void transport_segmented_setup_application_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
283     nonce[0] = 0x01;
284     transport_segmented_setup_nonce(nonce, pdu);
285     mesh_print_hex("AppNonce", nonce, 13);
286 }
287 
288 static void transport_segmented_setup_device_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
289     nonce[0] = 0x02;
290     transport_segmented_setup_nonce(nonce, pdu);
291     mesh_print_hex("DeviceNonce", nonce, 13);
292 }
293 
294 static void mesh_upper_unsegmented_control_message_received(mesh_unsegmented_incoming_pdu_t * unsegmented_incoming_pdu){
295     if (mesh_control_message_handler){
296         mesh_control_message_handler((mesh_pdu_t*) unsegmented_incoming_pdu);
297     } else {
298         mesh_network_pdu_t * network_pdu =unsegmented_incoming_pdu->segment;
299         uint8_t * lower_transport_pdu     = mesh_network_pdu_data(network_pdu);
300         uint8_t  opcode = lower_transport_pdu[0];
301         printf("[!] Unhandled Control message with opcode %02x\n", opcode);
302         // done
303         mesh_lower_transport_message_processed_by_higher_layer((mesh_pdu_t*) unsegmented_incoming_pdu);
304     }
305 }
306 
307 static void mesh_upper_transport_process_message_done(mesh_message_pdu_t *message_pdu){
308     crypto_active = 0;
309     btstack_assert(message_pdu == &incoming_message_pdu_singleton);
310     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&incoming_message_pdu_singleton.segments);
311     if (mesh_network_control(network_pdu)) {
312         btstack_assert(0);
313     } else {
314         btstack_assert(network_pdu != NULL);
315         mesh_network_pdu_free(network_pdu);
316         mesh_pdu_t * pdu = (mesh_pdu_t *) incoming_unsegmented_pdu_raw;
317         incoming_unsegmented_pdu_raw = NULL;
318         mesh_lower_transport_message_processed_by_higher_layer(pdu);
319     }
320     mesh_upper_transport_run();
321 }
322 
323 static void mesh_upper_transport_process_unsegmented_message_done(mesh_pdu_t * pdu){
324     btstack_assert(pdu != NULL);
325     btstack_assert(pdu->pdu_type == MESH_PDU_TYPE_UNSEGMENTED_INCOMING);
326 
327     mesh_unsegmented_incoming_pdu_t * unsegmented_incoming_pdu = (mesh_unsegmented_incoming_pdu_t *) pdu;
328     btstack_assert(unsegmented_incoming_pdu == incoming_unsegmented_pdu_raw);
329 
330     crypto_active = 0;
331     incoming_unsegmented_pdu_raw = NULL;
332     mesh_network_pdu_t * network_pdu = unsegmented_incoming_pdu->segment;
333     if (!mesh_network_control(network_pdu)) {
334         mesh_network_pdu_free(network_pdu);
335     }
336 
337     mesh_lower_transport_message_processed_by_higher_layer(pdu);
338     mesh_upper_transport_run();
339 }
340 
341 static void mesh_upper_transport_process_segmented_access_message_done(mesh_access_pdu_t *access_pdu){
342     crypto_active = 0;
343     btstack_assert(mesh_access_ctl(access_pdu) == 0);
344     incoming_access_pdu_encrypted = NULL;
345     mesh_upper_transport_run();
346 }
347 
348 static void mesh_upper_transport_validate_unsegmented_message_ccm(void * arg){
349     UNUSED(arg);
350 
351     uint8_t * lower_transport_pdu = mesh_network_pdu_data(incoming_network_pdu_decoded);
352     uint8_t trans_mic_len = 4;
353 
354     // store TransMIC
355     uint8_t trans_mic[8];
356     btstack_crypto_ccm_get_authentication_value(&ccm, trans_mic);
357     mesh_print_hex("TransMIC", trans_mic, trans_mic_len);
358 
359     uint8_t * upper_transport_pdu     = mesh_network_pdu_data(incoming_network_pdu_decoded) + 1;
360     uint8_t   upper_transport_pdu_len = mesh_network_pdu_len(incoming_network_pdu_decoded)  - 1;
361 
362     mesh_print_hex("Decryted PDU", upper_transport_pdu, upper_transport_pdu_len - trans_mic_len);
363 
364     if (memcmp(trans_mic, &upper_transport_pdu[upper_transport_pdu_len - trans_mic_len], trans_mic_len) == 0){
365         printf("TransMIC matches\n");
366 
367         // remove TransMIC from payload
368         incoming_network_pdu_decoded->len -= trans_mic_len;
369 
370         // if virtual address, update dst to pseudo_dst
371         if (mesh_network_address_virtual(mesh_network_dst(incoming_network_pdu_decoded))){
372             big_endian_store_16(incoming_network_pdu_decoded->data, 7, mesh_transport_key_it.address->pseudo_dst);
373         }
374 
375         // pass to upper layer
376         if (mesh_access_message_handler){
377             mesh_pdu_t * pdu = (mesh_pdu_t*) incoming_network_pdu_decoded;
378             incoming_network_pdu_decoded = NULL;
379             mesh_access_message_handler((mesh_pdu_t*) &incoming_message_pdu_singleton);
380         } else {
381             printf("[!] Unhandled Unsegmented Access message\n");
382             // done
383             mesh_upper_transport_process_unsegmented_message_done((mesh_pdu_t*) incoming_unsegmented_pdu_raw);
384         }
385 
386         printf("\n");
387     } else {
388         uint8_t afk = lower_transport_pdu[0] & 0x40;
389         if (afk){
390             printf("TransMIC does not match, try next key\n");
391             mesh_upper_transport_validate_unsegmented_message();
392         } else {
393             printf("TransMIC does not match device key, done\n");
394             // done
395             mesh_upper_transport_process_unsegmented_message_done((mesh_pdu_t*) incoming_unsegmented_pdu_raw);
396         }
397     }
398 }
399 
400 static void mesh_upper_transport_validate_segmented_message_ccm(void * arg){
401     UNUSED(arg);
402 
403     uint8_t * upper_transport_pdu     = incoming_access_pdu_decrypted->data;
404     uint8_t   upper_transport_pdu_len = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
405 
406     mesh_print_hex("Decrypted PDU", upper_transport_pdu, upper_transport_pdu_len);
407 
408     // store TransMIC
409     uint8_t trans_mic[8];
410     btstack_crypto_ccm_get_authentication_value(&ccm, trans_mic);
411     mesh_print_hex("TransMIC", trans_mic, incoming_access_pdu_decrypted->transmic_len);
412 
413     if (memcmp(trans_mic, &upper_transport_pdu[upper_transport_pdu_len], incoming_access_pdu_decrypted->transmic_len) == 0){
414         printf("TransMIC matches\n");
415 
416         // remove TransMIC from payload
417         incoming_access_pdu_decrypted->len -= incoming_access_pdu_decrypted->transmic_len;
418 
419         // if virtual address, update dst to pseudo_dst
420         if (mesh_network_address_virtual(mesh_access_dst(incoming_access_pdu_decrypted))){
421             big_endian_store_16(incoming_access_pdu_decrypted->network_header, 7, mesh_transport_key_it.address->pseudo_dst);
422         }
423 
424         // pass to upper layer
425         btstack_assert(mesh_access_message_handler != NULL);
426         mesh_pdu_t * pdu = (mesh_pdu_t*) incoming_access_pdu_decrypted;
427         incoming_network_pdu_decoded = NULL;
428         mesh_access_message_handler(pdu);
429 
430         printf("\n");
431 
432     } else {
433         uint8_t akf = incoming_access_pdu_decrypted->akf_aid_control & 0x40;
434         if (akf){
435             printf("TransMIC does not match, try next key\n");
436             mesh_upper_transport_validate_segmented_message();
437         } else {
438             printf("TransMIC does not match device key, done\n");
439             // done
440             mesh_upper_transport_process_segmented_access_message_done(incoming_access_pdu_decrypted);
441         }
442     }
443 }
444 
445 static void mesh_upper_transport_validate_segmented_message_digest(void * arg){
446     UNUSED(arg);
447     uint8_t   upper_transport_pdu_len      = incoming_access_pdu_encrypted->len - incoming_access_pdu_encrypted->transmic_len;
448     uint8_t * upper_transport_pdu_data_in  = incoming_access_pdu_encrypted->data;
449     uint8_t * upper_transport_pdu_data_out = incoming_access_pdu_decrypted->data;
450     btstack_crypto_ccm_decrypt_block(&ccm, upper_transport_pdu_len, upper_transport_pdu_data_in, upper_transport_pdu_data_out, &mesh_upper_transport_validate_segmented_message_ccm, NULL);
451 }
452 
453 static void mesh_upper_transport_validate_unsegmented_message_digest(void * arg){
454     UNUSED(arg);
455     mesh_network_pdu_t * network_pdu = incoming_unsegmented_pdu_raw->segment;
456     uint8_t   trans_mic_len = 4;
457     uint8_t   lower_transport_pdu_len      = network_pdu->len - 9;
458     uint8_t * upper_transport_pdu_data_in  = &network_pdu->data[10];
459     uint8_t * upper_transport_pdu_data_out = &incoming_network_pdu_decoded->data[10];
460     uint8_t   upper_transport_pdu_len      = lower_transport_pdu_len - 1 - trans_mic_len;
461     btstack_crypto_ccm_decrypt_block(&ccm, upper_transport_pdu_len, upper_transport_pdu_data_in, upper_transport_pdu_data_out, &mesh_upper_transport_validate_unsegmented_message_ccm, NULL);
462 }
463 
464 static void mesh_upper_transport_validate_unsegmented_message(void){
465 
466     if (!mesh_transport_key_and_virtual_address_iterator_has_more(&mesh_transport_key_it)){
467         printf("No valid transport key found\n");
468         mesh_upper_transport_process_unsegmented_message_done((mesh_pdu_t*) incoming_unsegmented_pdu_raw);
469         return;
470     }
471     mesh_transport_key_and_virtual_address_iterator_next(&mesh_transport_key_it);
472     const mesh_transport_key_t * message_key = mesh_transport_key_it.key;
473 
474     mesh_network_pdu_t * network_pdu = incoming_unsegmented_pdu_raw->segment;
475     if (message_key->akf){
476         transport_unsegmented_setup_application_nonce(application_nonce, network_pdu);
477     } else {
478         transport_unsegmented_setup_device_nonce(application_nonce, network_pdu);
479     }
480 
481     // store application / device key index
482     mesh_print_hex("AppOrDevKey", message_key->key, 16);
483     incoming_message_pdu_singleton.appkey_index = message_key->appkey_index;
484 
485     // unsegmented message have TransMIC of 32 bit
486     uint8_t trans_mic_len = 4;
487     printf("Unsegmented Access message with TransMIC len 4\n");
488 
489     uint8_t   lower_transport_pdu_len = network_pdu->len - 9;
490     uint8_t * upper_transport_pdu_data = &network_pdu->data[10];
491     uint8_t   upper_transport_pdu_len  = lower_transport_pdu_len - 1 - trans_mic_len;
492 
493     mesh_print_hex("EncAccessPayload", upper_transport_pdu_data, upper_transport_pdu_len);
494 
495     // decrypt ccm
496     crypto_active = 1;
497     uint16_t aad_len  = 0;
498     if (mesh_network_address_virtual(mesh_network_dst(incoming_network_pdu_decoded))){
499         aad_len  = 16;
500     }
501     btstack_crypto_ccm_init(&ccm, message_key->key, application_nonce, upper_transport_pdu_len, aad_len, trans_mic_len);
502     if (aad_len){
503         btstack_crypto_ccm_digest(&ccm, (uint8_t*) mesh_transport_key_it.address->label_uuid, aad_len, &mesh_upper_transport_validate_unsegmented_message_digest, NULL);
504     } else {
505         mesh_upper_transport_validate_unsegmented_message_digest(incoming_network_pdu_decoded);
506     }
507 }
508 
509 static void mesh_upper_transport_validate_segmented_message(void){
510     uint8_t * upper_transport_pdu_data =  incoming_access_pdu_decrypted->data;
511     uint8_t   upper_transport_pdu_len  = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
512 
513     if (!mesh_transport_key_and_virtual_address_iterator_has_more(&mesh_transport_key_it)){
514         printf("No valid transport key found\n");
515         mesh_upper_transport_process_segmented_access_message_done(incoming_access_pdu_decrypted);
516         return;
517     }
518     mesh_transport_key_and_virtual_address_iterator_next(&mesh_transport_key_it);
519     const mesh_transport_key_t * message_key = mesh_transport_key_it.key;
520 
521     if (message_key->akf){
522         transport_segmented_setup_application_nonce(application_nonce, (mesh_pdu_t *) incoming_access_pdu_encrypted);
523     } else {
524         transport_segmented_setup_device_nonce(application_nonce, (mesh_pdu_t *) incoming_access_pdu_encrypted);
525     }
526 
527     // store application / device key index
528     mesh_print_hex("AppOrDevKey", message_key->key, 16);
529     incoming_access_pdu_decrypted->appkey_index = message_key->appkey_index;
530 
531     mesh_print_hex("EncAccessPayload", upper_transport_pdu_data, upper_transport_pdu_len);
532 
533     // decrypt ccm
534     crypto_active = 1;
535     uint16_t aad_len  = 0;
536     if (mesh_network_address_virtual(mesh_access_dst(incoming_access_pdu_decrypted))){
537         aad_len  = 16;
538     }
539     btstack_crypto_ccm_init(&ccm, message_key->key, application_nonce, upper_transport_pdu_len, aad_len, incoming_access_pdu_decrypted->transmic_len);
540 
541     if (aad_len){
542         btstack_crypto_ccm_digest(&ccm, (uint8_t *) mesh_transport_key_it.address->label_uuid, aad_len, &mesh_upper_transport_validate_segmented_message_digest, NULL);
543     } else {
544         mesh_upper_transport_validate_segmented_message_digest(NULL);
545     }
546 }
547 
548 static void mesh_upper_transport_process_unsegmented_access_message(void){
549     // copy original pdu
550     mesh_network_pdu_t * raw_network_pdu = incoming_unsegmented_pdu_raw->segment;
551     incoming_network_pdu_decoded->len = raw_network_pdu->len;
552     (void)memcpy(incoming_network_pdu_decoded->data,
553                  raw_network_pdu->data,
554                  incoming_network_pdu_decoded->len);
555 
556     //
557     uint8_t * lower_transport_pdu     = &raw_network_pdu->data[9];
558     uint8_t   lower_transport_pdu_len = raw_network_pdu->len - 9;
559 
560     mesh_print_hex("Lower Transport network pdu", &raw_network_pdu->data[9], lower_transport_pdu_len);
561 
562     uint8_t aid =  lower_transport_pdu[0] & 0x3f;
563     uint8_t akf = (lower_transport_pdu[0] & 0x40) >> 6;
564     printf("AKF: %u\n",   akf);
565     printf("AID: %02x\n", aid);
566 
567     mesh_transport_key_and_virtual_address_iterator_init(&mesh_transport_key_it, mesh_network_dst(incoming_network_pdu_decoded),
568             incoming_network_pdu_decoded->netkey_index, akf, aid);
569     mesh_upper_transport_validate_unsegmented_message();
570 }
571 
572 static void mesh_upper_transport_process_message(void){
573     // copy original pdu
574     (void)memcpy(incoming_access_pdu_decrypted, incoming_access_pdu_encrypted,
575                  sizeof(mesh_transport_pdu_t));
576 
577     //
578     uint8_t * upper_transport_pdu     =  incoming_access_pdu_decrypted->data;
579     uint8_t   upper_transport_pdu_len = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
580     mesh_print_hex("Upper Transport pdu", upper_transport_pdu, upper_transport_pdu_len);
581 
582     uint8_t aid = incoming_access_pdu_decrypted->akf_aid_control & 0x3f;
583     uint8_t akf = (incoming_access_pdu_decrypted->akf_aid_control & 0x40) >> 6;
584 
585     printf("AKF: %u\n",   akf);
586     printf("AID: %02x\n", aid);
587 
588     mesh_transport_key_and_virtual_address_iterator_init(&mesh_transport_key_it, mesh_access_dst(incoming_access_pdu_decrypted),
589                                                          incoming_access_pdu_decrypted->netkey_index, akf, aid);
590     mesh_upper_transport_validate_segmented_message();
591 }
592 
593 static void mesh_upper_transport_message_received(mesh_pdu_t * pdu){
594     btstack_linked_list_add_tail(&upper_transport_incoming, (btstack_linked_item_t*) pdu);
595     mesh_upper_transport_run();
596 }
597 
598 
599 
600 static void mesh_upper_transport_pdu_handler(mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu){
601     switch (callback_type){
602         case MESH_TRANSPORT_PDU_RECEIVED:
603             mesh_upper_transport_message_received(pdu);
604             break;
605         case MESH_TRANSPORT_PDU_SENT:
606             // notify upper layer (or just free pdu)
607             if (higher_layer_handler){
608                 higher_layer_handler(callback_type, status, pdu);
609             } else {
610                 mesh_upper_transport_pdu_free(pdu);
611             }
612             mesh_upper_transport_run();
613             break;
614         default:
615             break;
616     }
617 }
618 static void mesh_upper_transport_send_unsegmented_access_pdu_ccm(void * arg){
619     crypto_active = 0;
620 
621     mesh_message_pdu_t * message_pdu = (mesh_message_pdu_t *) arg;
622     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_first_item(&message_pdu->segments);
623 
624     uint8_t * upper_transport_pdu     = mesh_network_pdu_data(network_pdu) + 1;
625     uint8_t   upper_transport_pdu_len = mesh_network_pdu_len(network_pdu)  - 1;
626     mesh_print_hex("EncAccessPayload", upper_transport_pdu, upper_transport_pdu_len);
627     // store TransMIC
628     btstack_crypto_ccm_get_authentication_value(&ccm, &upper_transport_pdu[upper_transport_pdu_len]);
629     mesh_print_hex("TransMIC", &upper_transport_pdu[upper_transport_pdu_len], 4);
630     network_pdu->len        += 4;
631     upper_transport_pdu_len += 4;
632     mesh_print_hex("UpperTransportPDU", upper_transport_pdu, upper_transport_pdu_len);
633     // send network pdu
634     mesh_lower_transport_send_pdu((mesh_pdu_t*) message_pdu);
635 }
636 
637 static void mesh_upper_transport_send_segmented_pdu(mesh_transport_pdu_t * transport_pdu){
638     mesh_lower_transport_send_pdu((mesh_pdu_t*) transport_pdu);
639 }
640 
641 static void mesh_upper_transport_send_segmented_access_pdu_ccm(void * arg){
642     crypto_active = 0;
643 
644     mesh_transport_pdu_t * transport_pdu = (mesh_transport_pdu_t *) arg;
645     mesh_print_hex("EncAccessPayload", transport_pdu->data, transport_pdu->len);
646     // store TransMIC
647     btstack_crypto_ccm_get_authentication_value(&ccm, &transport_pdu->data[transport_pdu->len]);
648     mesh_print_hex("TransMIC", &transport_pdu->data[transport_pdu->len], transport_pdu->transmic_len);
649     transport_pdu->len += transport_pdu->transmic_len;
650     mesh_print_hex("UpperTransportPDU", transport_pdu->data, transport_pdu->len);
651     mesh_upper_transport_send_segmented_pdu(transport_pdu);
652 }
653 
654 static uint8_t mesh_upper_transport_setup_unsegmented_control_pdu(mesh_network_pdu_t * network_pdu, uint16_t netkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t opcode,
655                           const uint8_t * control_pdu_data, uint16_t control_pdu_len){
656 
657     if (control_pdu_len > 11) return 1;
658 
659     const mesh_network_key_t * network_key = mesh_network_key_list_get(netkey_index);
660     if (!network_key) return 1;
661 
662     uint8_t transport_pdu_data[12];
663     transport_pdu_data[0] = opcode;
664     (void)memcpy(&transport_pdu_data[1], control_pdu_data, control_pdu_len);
665     uint16_t transport_pdu_len = control_pdu_len + 1;
666 
667     // setup network_pdu
668     mesh_network_setup_pdu(network_pdu, netkey_index, network_key->nid, 1, ttl, 0, src, dest, transport_pdu_data, transport_pdu_len);
669 
670     return 0;
671 }
672 
673 static uint8_t mesh_upper_transport_setup_segmented_control_pdu(mesh_transport_pdu_t * transport_pdu, uint16_t netkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t opcode,
674                           const uint8_t * control_pdu_data, uint16_t control_pdu_len){
675 
676     if (control_pdu_len > 256) return 1;
677 
678     const mesh_network_key_t * network_key = mesh_network_key_list_get(netkey_index);
679     if (!network_key) return 1;
680 
681     (void)memcpy(transport_pdu->data, control_pdu_data, control_pdu_len);
682     transport_pdu->len = control_pdu_len;
683     transport_pdu->netkey_index = netkey_index;
684     transport_pdu->akf_aid_control = opcode;
685     transport_pdu->transmic_len = 0;    // no TransMIC for control
686     mesh_transport_set_nid_ivi(transport_pdu, network_key->nid);
687     mesh_transport_set_src(transport_pdu, src);
688     mesh_transport_set_dest(transport_pdu, dest);
689     mesh_transport_set_ctl_ttl(transport_pdu, 0x80 | ttl);
690 
691     return 0;
692 }
693 
694 uint8_t mesh_upper_transport_setup_control_pdu(mesh_pdu_t * pdu, uint16_t netkey_index,
695                                                uint8_t ttl, uint16_t src, uint16_t dest, uint8_t opcode, const uint8_t * control_pdu_data, uint16_t control_pdu_len){
696     switch (pdu->pdu_type){
697         case MESH_PDU_TYPE_NETWORK:
698             return mesh_upper_transport_setup_unsegmented_control_pdu((mesh_network_pdu_t *) pdu, netkey_index, ttl, src, dest, opcode, control_pdu_data, control_pdu_len);
699         case MESH_PDU_TYPE_TRANSPORT:
700             return mesh_upper_transport_setup_segmented_control_pdu((mesh_transport_pdu_t *) pdu, netkey_index, ttl, src, dest, opcode, control_pdu_data, control_pdu_len);
701         case MESH_PDU_TYPE_MESSAGE:
702             btstack_assert(0);
703             break;
704         default:
705             return 1;
706     }
707 }
708 
709 static uint8_t mesh_upper_transport_setup_unsegmented_access_pdu_header(mesh_message_pdu_t * message_pdu, uint16_t netkey_index,
710         uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest){
711 
712     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_first_item(&message_pdu->segments);
713 
714     // get app or device key
715     const mesh_transport_key_t * appkey;
716     appkey = mesh_transport_key_get(appkey_index);
717     if (appkey == NULL){
718         printf("appkey_index %x unknown\n", appkey_index);
719         return 1;
720     }
721     uint8_t akf_aid = (appkey->akf << 6) | appkey->aid;
722 
723     // lookup network by netkey_index
724     const mesh_network_key_t * network_key = mesh_network_key_list_get(netkey_index);
725     if (!network_key) return 1;
726 
727     message_pdu->appkey_index = appkey_index;
728 
729     network_pdu->data[9] = akf_aid;
730     // setup network_pdu
731     mesh_network_setup_pdu_header(network_pdu, netkey_index, network_key->nid, 0, ttl, 0, src, dest);
732     return 0;
733 }
734 
735 static uint8_t mesh_upper_transport_setup_unsegmented_access_pdu(mesh_message_pdu_t * message_pdu, uint16_t netkey_index, uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest,
736                                                        const uint8_t * access_pdu_data, uint8_t access_pdu_len){
737 
738     int status = mesh_upper_transport_setup_unsegmented_access_pdu_header(message_pdu, netkey_index, appkey_index, ttl, src, dest);
739     if (status) return status;
740 
741     // store in transport pdu
742     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_first_item(&message_pdu->segments);
743     (void)memcpy(&network_pdu->data[10], access_pdu_data, access_pdu_len);
744     network_pdu->len = 10 + access_pdu_len;
745     return 0;
746 }
747 
748 static uint8_t mesh_upper_transport_setup_segmented_access_pdu_header(mesh_transport_pdu_t * transport_pdu, uint16_t netkey_index,
749     uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic){
750 
751     // get app or device key
752     const mesh_transport_key_t *appkey;
753     appkey = mesh_transport_key_get(appkey_index);
754     if (appkey == NULL) {
755         printf("[!] Upper transport, setup segmented Access PDU - appkey_index %x unknown\n", appkey_index);
756         return 1;
757     }
758     uint8_t akf_aid = (appkey->akf << 6) | appkey->aid;
759 
760     // lookup network by netkey_index
761     const mesh_network_key_t *network_key = mesh_network_key_list_get(netkey_index);
762     if (!network_key) return 1;
763     if (network_key == NULL) {
764         printf("[!] Upper transport, setup segmented Access PDU - netkey_index %x unknown\n", appkey_index);
765         return 1;
766     }
767 
768     const uint8_t trans_mic_len = szmic ? 8 : 4;
769 
770     // store in transport pdu
771     transport_pdu->transmic_len = trans_mic_len;
772     transport_pdu->netkey_index = netkey_index;
773     transport_pdu->appkey_index = appkey_index;
774     transport_pdu->akf_aid_control = akf_aid;
775     mesh_transport_set_nid_ivi(transport_pdu, network_key->nid | ((mesh_get_iv_index_for_tx() & 1) << 7));
776     mesh_transport_set_src(transport_pdu, src);
777     mesh_transport_set_dest(transport_pdu, dest);
778     mesh_transport_set_ctl_ttl(transport_pdu, ttl);
779     return 0;
780 }
781 
782 
783 static uint8_t mesh_upper_transport_setup_segmented_access_pdu(mesh_transport_pdu_t * transport_pdu, uint16_t netkey_index, uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest,
784                           uint8_t szmic, const uint8_t * access_pdu_data, uint8_t access_pdu_len){
785     int status = mesh_upper_transport_setup_segmented_access_pdu_header(transport_pdu, netkey_index, appkey_index, ttl, src, dest, szmic);
786     if (status) return status;
787 
788     // store in transport pdu
789     (void)memcpy(transport_pdu->data, access_pdu_data, access_pdu_len);
790     transport_pdu->len = access_pdu_len;
791     return 0;
792 }
793 uint8_t mesh_upper_transport_setup_access_pdu_header(mesh_pdu_t * pdu, uint16_t netkey_index, uint16_t appkey_index,
794                                               uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic){
795     switch (pdu->pdu_type){
796         case MESH_PDU_TYPE_NETWORK:
797             btstack_assert(0);
798         case MESH_PDU_TYPE_TRANSPORT:
799             return mesh_upper_transport_setup_segmented_access_pdu_header((mesh_transport_pdu_t *) pdu, netkey_index, appkey_index, ttl, src, dest, szmic);
800         case MESH_PDU_TYPE_MESSAGE:
801             return mesh_upper_transport_setup_unsegmented_access_pdu_header((mesh_message_pdu_t *) pdu, netkey_index, appkey_index, ttl, src, dest);
802         default:
803             return 1;
804     }
805 }
806 
807 uint8_t mesh_upper_transport_setup_access_pdu(mesh_pdu_t * pdu, uint16_t netkey_index, uint16_t appkey_index,
808                                               uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic,
809                                               const uint8_t * access_pdu_data, uint8_t access_pdu_len){
810     switch (pdu->pdu_type){
811         case MESH_PDU_TYPE_NETWORK:
812             btstack_assert(0);
813             break;
814         case MESH_PDU_TYPE_MESSAGE:
815             return mesh_upper_transport_setup_unsegmented_access_pdu((mesh_message_pdu_t *) pdu, netkey_index, appkey_index, ttl, src, dest, access_pdu_data, access_pdu_len);
816         case MESH_PDU_TYPE_TRANSPORT:
817             return mesh_upper_transport_setup_segmented_access_pdu((mesh_transport_pdu_t *) pdu, netkey_index, appkey_index, ttl, src, dest, szmic, access_pdu_data, access_pdu_len);
818         default:
819             return 1;
820     }
821 }
822 
823 static void mesh_upper_transport_send_unsegmented_access_pdu_digest(void * arg){
824     mesh_message_pdu_t * message_pdu = (mesh_message_pdu_t *) arg;
825     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_first_item(&message_pdu->segments);
826     uint8_t * access_pdu_data = mesh_network_pdu_data(network_pdu) + 1;
827     uint16_t  access_pdu_len  = mesh_network_pdu_len(network_pdu)  - 1;
828     btstack_crypto_ccm_encrypt_block(&ccm, access_pdu_len, access_pdu_data, access_pdu_data, &mesh_upper_transport_send_unsegmented_access_pdu_ccm, message_pdu);
829 }
830 
831 static mesh_transport_key_t * mesh_upper_transport_get_outgoing_appkey(uint16_t netkey_index, uint16_t appkey_index){
832     // Device Key is fixed
833     if (appkey_index == MESH_DEVICE_KEY_INDEX) {
834         return mesh_transport_key_get(appkey_index);
835     }
836 
837     // Get key refresh state from subnet
838     mesh_subnet_t * subnet = mesh_subnet_get_by_netkey_index(netkey_index);
839     if (subnet == NULL) return NULL;
840 
841     // identify old and new app keys for given appkey_index
842     mesh_transport_key_t * old_key = NULL;
843     mesh_transport_key_t * new_key = NULL;
844     mesh_transport_key_iterator_t it;
845     mesh_transport_key_iterator_init(&it, netkey_index);
846     while (mesh_transport_key_iterator_has_more(&it)){
847         mesh_transport_key_t * transport_key = mesh_transport_key_iterator_get_next(&it);
848         if (transport_key->appkey_index != appkey_index) continue;
849         if (transport_key->old_key == 0) {
850             new_key = transport_key;
851         } else {
852             old_key = transport_key;
853         }
854     }
855 
856     // if no key is marked as old, just use the current one
857     if (old_key == NULL) return new_key;
858 
859     // use new key if it exists in phase two
860     if ((subnet->key_refresh == MESH_KEY_REFRESH_SECOND_PHASE) && (new_key != NULL)){
861         return new_key;
862     } else {
863         return old_key;
864     }
865 }
866 
867 static void mesh_upper_transport_send_unsegmented_access_pdu(mesh_message_pdu_t * message_pdu){
868 
869     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_first_item(&message_pdu->segments);
870 
871     // if dst is virtual address, lookup label uuid and hash
872     uint16_t aad_len = 0;
873     mesh_virtual_address_t * virtual_address = NULL;
874     uint16_t dst = mesh_network_dst(network_pdu);
875     if (mesh_network_address_virtual(dst)){
876         virtual_address = mesh_virtual_address_for_pseudo_dst(dst);
877         if (!virtual_address){
878             printf("No virtual address register for pseudo dst %4x\n", dst);
879             btstack_memory_mesh_network_pdu_free(network_pdu);
880             return;
881         }
882         aad_len = 16;
883         big_endian_store_16(network_pdu->data, 7, virtual_address->hash);
884     }
885 
886     // reserve slot
887     mesh_lower_transport_reserve_slot();
888 
889     // Nonce for Access Payload based on Network Sequence number: needs to be fixed now and lower layers need to send packet in right order
890     uint32_t seq = mesh_sequence_number_next();
891     mesh_network_pdu_set_seq(network_pdu, seq);
892 
893     // Dump PDU
894     printf("[+] Upper transport, send unsegmented Access PDU - dest %04x, seq %06x\n", dst, mesh_network_seq(network_pdu));
895     mesh_print_hex("Access Payload", &network_pdu->data[10], network_pdu->len - 10);
896 
897     // setup nonce
898     uint16_t appkey_index = message_pdu->appkey_index;
899     if (appkey_index == MESH_DEVICE_KEY_INDEX){
900         transport_unsegmented_setup_device_nonce(application_nonce, network_pdu);
901     } else {
902         transport_unsegmented_setup_application_nonce(application_nonce, network_pdu);
903     }
904 
905     // get app or device key
906     const mesh_transport_key_t * appkey = mesh_upper_transport_get_outgoing_appkey(network_pdu->netkey_index, appkey_index);
907     mesh_print_hex("AppOrDevKey", appkey->key, 16);
908 
909     // encrypt ccm
910     uint8_t   trans_mic_len = 4;
911     uint16_t  access_pdu_len  = mesh_network_pdu_len(network_pdu)  - 1;
912     crypto_active = 1;
913 
914     btstack_crypto_ccm_init(&ccm, appkey->key, application_nonce, access_pdu_len, aad_len, trans_mic_len);
915     if (virtual_address){
916         mesh_print_hex("LabelUUID", virtual_address->label_uuid, 16);
917         btstack_crypto_ccm_digest(&ccm, virtual_address->label_uuid, 16, &mesh_upper_transport_send_unsegmented_access_pdu_digest, message_pdu);
918     } else {
919         mesh_upper_transport_send_unsegmented_access_pdu_digest(message_pdu);
920     }
921 }
922 
923 static void mesh_upper_transport_send_segmented_access_pdu_digest(void *arg){
924     mesh_transport_pdu_t * transport_pdu = (mesh_transport_pdu_t *) arg;
925     uint16_t  access_pdu_len  = transport_pdu->len;
926     uint8_t * access_pdu_data = transport_pdu->data;
927     btstack_crypto_ccm_encrypt_block(&ccm, access_pdu_len,access_pdu_data, access_pdu_data, &mesh_upper_transport_send_segmented_access_pdu_ccm, transport_pdu);
928 }
929 
930 static void mesh_upper_transport_send_segmented_access_pdu(mesh_transport_pdu_t * transport_pdu){
931 
932     // if dst is virtual address, lookup label uuid and hash
933     uint16_t aad_len = 0;
934     mesh_virtual_address_t * virtual_address = NULL;
935     uint16_t dst = mesh_transport_dst(transport_pdu);
936     if (mesh_network_address_virtual(dst)){
937         virtual_address = mesh_virtual_address_for_pseudo_dst(dst);
938         if (!virtual_address){
939             printf("No virtual address register for pseudo dst %4x\n", dst);
940             btstack_memory_mesh_transport_pdu_free(transport_pdu);
941             return;
942         }
943         // printf("Using hash %4x with LabelUUID: ", virtual_address->hash);
944         // printf_hexdump(virtual_address->label_uuid, 16);
945         aad_len = 16;
946         big_endian_store_16(transport_pdu->network_header, 7, virtual_address->hash);
947     }
948 
949     // get app or device key
950     uint16_t appkey_index = transport_pdu->appkey_index;
951     const mesh_transport_key_t * appkey = mesh_upper_transport_get_outgoing_appkey(transport_pdu->netkey_index, appkey_index);
952     if (appkey == NULL){
953         printf("AppKey %04x not found, drop message\n", appkey_index);
954         btstack_memory_mesh_transport_pdu_free(transport_pdu);
955         return;
956     }
957 
958     // reserve slot
959     mesh_lower_transport_reserve_slot();
960 
961     // reserve one sequence number, which is also used to encrypt access payload
962     uint32_t seq = mesh_sequence_number_next();
963     transport_pdu->flags |= MESH_TRANSPORT_FLAG_SEQ_RESERVED;
964     mesh_transport_set_seq(transport_pdu, seq);
965 
966     // Dump PDU
967     printf("[+] Upper transport, send segmented Access PDU - dest %04x, seq %06x\n", dst, mesh_transport_seq(transport_pdu));
968     mesh_print_hex("Access Payload", transport_pdu->data, transport_pdu->len);
969 
970     // setup nonce - uses dst, so after pseudo address translation
971     if (appkey_index == MESH_DEVICE_KEY_INDEX){
972         transport_segmented_setup_device_nonce(application_nonce, (mesh_pdu_t *) transport_pdu);
973     } else {
974         transport_segmented_setup_application_nonce(application_nonce, (mesh_pdu_t *) transport_pdu);
975     }
976 
977     // Dump key
978     mesh_print_hex("AppOrDevKey", appkey->key, 16);
979 
980     // encrypt ccm
981     uint8_t   transmic_len    = transport_pdu->transmic_len;
982     uint16_t  access_pdu_len  = transport_pdu->len;
983     crypto_active = 1;
984     btstack_crypto_ccm_init(&ccm, appkey->key, application_nonce, access_pdu_len, aad_len, transmic_len);
985     if (virtual_address){
986         mesh_print_hex("LabelUUID", virtual_address->label_uuid, 16);
987         btstack_crypto_ccm_digest(&ccm, virtual_address->label_uuid, 16, &mesh_upper_transport_send_segmented_access_pdu_digest, transport_pdu);
988     } else {
989         mesh_upper_transport_send_segmented_access_pdu_digest(transport_pdu);
990     }
991 }
992 
993 static void mesh_upper_transport_send_unsegmented_control_pdu(mesh_network_pdu_t * network_pdu){
994     // reserve slot
995     mesh_lower_transport_reserve_slot();
996     // reserve sequence number
997     uint32_t seq = mesh_sequence_number_next();
998     mesh_network_pdu_set_seq(network_pdu, seq);
999     // Dump PDU
1000     uint8_t opcode = network_pdu->data[9];
1001     printf("[+] Upper transport, send unsegmented Control PDU %p - seq %06x opcode %02x\n", network_pdu, seq, opcode);
1002     mesh_print_hex("Access Payload", &network_pdu->data[10], network_pdu->len - 10);
1003     // send
1004     mesh_lower_transport_send_pdu((mesh_pdu_t *) network_pdu);
1005 }
1006 
1007 static void mesh_upper_transport_send_segmented_control_pdu(mesh_transport_pdu_t * transport_pdu){
1008     // reserve slot
1009     mesh_lower_transport_reserve_slot();
1010     // reserve sequence number
1011     uint32_t seq = mesh_sequence_number_next();
1012     transport_pdu->flags |= MESH_TRANSPORT_FLAG_SEQ_RESERVED;
1013     mesh_transport_set_seq(transport_pdu, seq);
1014     // Dump PDU
1015     uint8_t opcode = transport_pdu->data[0];
1016     printf("[+] Upper transport, send segmented Control PDU %p - seq %06x opcode %02x\n", transport_pdu, seq, opcode);
1017     mesh_print_hex("Access Payload", &transport_pdu->data[1], transport_pdu->len - 1);
1018     // send
1019     mesh_upper_transport_send_segmented_pdu(transport_pdu);
1020 }
1021 
1022 static void mesh_upper_transport_run(void){
1023 
1024     while(!btstack_linked_list_empty(&upper_transport_incoming)){
1025 
1026         if (crypto_active) return;
1027 
1028         // peek at next message
1029         mesh_pdu_t * pdu =  (mesh_pdu_t *) btstack_linked_list_get_first_item(&upper_transport_incoming);
1030         mesh_network_pdu_t   * network_pdu;
1031         mesh_transport_pdu_t * transport_pdu;
1032         mesh_message_pdu_t   * message_pdu;
1033         mesh_unsegmented_incoming_pdu_t * unsegmented_pdu;
1034         switch (pdu->pdu_type){
1035             case MESH_PDU_TYPE_UNSEGMENTED_INCOMING:
1036                 unsegmented_pdu = (mesh_unsegmented_incoming_pdu_t *) pdu;
1037                 network_pdu = unsegmented_pdu->segment;
1038                 btstack_assert(network_pdu != NULL);
1039                 incoming_unsegmented_pdu_raw = unsegmented_pdu;
1040                 // control?
1041                 if (mesh_network_control(network_pdu)) {
1042                     (void) btstack_linked_list_pop(&upper_transport_incoming);
1043                     mesh_upper_unsegmented_control_message_received(unsegmented_pdu);
1044                     break;
1045                 } else {
1046                     incoming_network_pdu_decoded = mesh_network_pdu_get();
1047                     if (!incoming_network_pdu_decoded) return;
1048 
1049                     (void) btstack_linked_list_pop(&upper_transport_incoming);
1050 
1051                     // use pre-allocated message pdu
1052                     incoming_message_pdu_singleton.pdu_header.pdu_type = MESH_PDU_TYPE_MESSAGE;
1053                     btstack_linked_list_add(&incoming_message_pdu_singleton.segments, (btstack_linked_item_t *) incoming_network_pdu_decoded);
1054                     mesh_upper_transport_process_unsegmented_access_message();
1055                 }
1056                 break;
1057             case MESH_PDU_TYPE_MESSAGE:
1058                 message_pdu = (mesh_message_pdu_t *) pdu;
1059                 uint8_t ctl = mesh_message_ctl(message_pdu);
1060                 if (ctl){
1061                     printf("Ignoring Segmented Control Message\n");
1062                     (void) btstack_linked_list_pop(&upper_transport_incoming);
1063                     mesh_lower_transport_message_processed_by_higher_layer(pdu);
1064                 } else {
1065 
1066                     incoming_access_pdu_encrypted = &incoming_access_pdu_encrypted_singleton;
1067                     incoming_access_pdu_encrypted->pdu_header.pdu_type = MESH_PDU_TYPE_ACCESS;
1068 
1069                     // flatten segmented message into mesh_transport_pdu_t
1070 
1071                     // assemble payload
1072                     while (message_pdu->segments){
1073                         mesh_network_pdu_t * segment  = (mesh_network_pdu_t *) btstack_linked_list_pop(&message_pdu->segments);
1074                         // get segment n
1075                         uint8_t * lower_transport_pdu = mesh_network_pdu_data(segment);
1076                         uint8_t   seg_o               =  ( big_endian_read_16(lower_transport_pdu, 2) >> 5) & 0x001f;
1077                         uint8_t * segment_data = &lower_transport_pdu[4];
1078                         (void)memcpy(&incoming_access_pdu_encrypted->data[seg_o * 12], segment_data, 12);
1079                     }
1080 
1081                     // copy meta data into encrypted pdu buffer
1082                     incoming_access_pdu_encrypted->len =  message_pdu->len;
1083                     incoming_access_pdu_encrypted->netkey_index =  message_pdu->netkey_index;
1084                     incoming_access_pdu_encrypted->transmic_len =  message_pdu->transmic_len;
1085                     incoming_access_pdu_encrypted->akf_aid_control =  message_pdu->akf_aid_control;
1086                     (void)memcpy(incoming_access_pdu_encrypted->network_header, message_pdu->network_header, 9);
1087 
1088                     mesh_print_hex("Assembled payload", incoming_access_pdu_encrypted->data, incoming_access_pdu_encrypted->len);
1089 
1090                     // copy meta data into decrypted pdu buffer
1091                     incoming_access_pdu_decrypted = &incoming_access_pdu_decrypted_singleton;
1092                     incoming_access_pdu_decrypted->pdu_header.pdu_type = MESH_PDU_TYPE_ACCESS;
1093                     incoming_access_pdu_decrypted->len =  message_pdu->len;
1094                     incoming_access_pdu_decrypted->netkey_index =  message_pdu->netkey_index;
1095                     incoming_access_pdu_decrypted->transmic_len =  message_pdu->transmic_len;
1096                     incoming_access_pdu_decrypted->akf_aid_control =  message_pdu->akf_aid_control;
1097                     (void)memcpy(incoming_access_pdu_decrypted->network_header, message_pdu->network_header, 9);
1098 
1099                     // free mesh message
1100                     mesh_lower_transport_message_processed_by_higher_layer((mesh_pdu_t *)message_pdu);
1101 
1102                     // get encoded transport pdu and start processing
1103                     (void) btstack_linked_list_pop(&upper_transport_incoming);
1104                     mesh_upper_transport_process_message();
1105                 }
1106                 break;
1107             default:
1108                 btstack_assert(0);
1109                 break;
1110         }
1111     }
1112 
1113     while (!btstack_linked_list_empty(&upper_transport_outgoing)){
1114 
1115         if (crypto_active) break;
1116 
1117         mesh_pdu_t * pdu =  (mesh_pdu_t *) btstack_linked_list_get_first_item(&upper_transport_outgoing);
1118         if (mesh_lower_transport_can_send_to_dest(mesh_pdu_dst(pdu)) == 0) break;
1119 
1120         (void) btstack_linked_list_pop(&upper_transport_outgoing);
1121 
1122         if (mesh_pdu_ctl(pdu)){
1123             switch (pdu->pdu_type){
1124                 case MESH_PDU_TYPE_NETWORK:
1125                     mesh_upper_transport_send_unsegmented_control_pdu((mesh_network_pdu_t *) pdu);
1126                     break;
1127                 case MESH_PDU_TYPE_MESSAGE:
1128                     btstack_assert(0);
1129                     break;
1130                 case MESH_PDU_TYPE_TRANSPORT:
1131                     mesh_upper_transport_send_segmented_control_pdu((mesh_transport_pdu_t *) pdu);
1132                     break;
1133                 default:
1134                     break;
1135             }
1136         } else {
1137             switch (pdu->pdu_type){
1138                 case MESH_PDU_TYPE_NETWORK:
1139                     btstack_assert(0);
1140                     break;
1141                 case MESH_PDU_TYPE_MESSAGE:
1142                     mesh_upper_transport_send_unsegmented_access_pdu((mesh_message_pdu_t *) pdu);
1143                     break;
1144                 case MESH_PDU_TYPE_TRANSPORT:
1145                     mesh_upper_transport_send_segmented_access_pdu((mesh_transport_pdu_t *) pdu);
1146                     break;
1147                 default:
1148                     break;
1149             }
1150         }
1151     }
1152 }
1153 
1154 void mesh_upper_transport_pdu_free(mesh_pdu_t * pdu){
1155     mesh_network_pdu_t   * network_pdu;
1156     mesh_transport_pdu_t * transport_pdu;
1157     mesh_message_pdu_t   * message_pdu;
1158     switch (pdu->pdu_type) {
1159         case MESH_PDU_TYPE_NETWORK:
1160             network_pdu = (mesh_network_pdu_t *) pdu;
1161             mesh_network_pdu_free(network_pdu);
1162             break;
1163         case MESH_PDU_TYPE_TRANSPORT:
1164             transport_pdu = (mesh_transport_pdu_t *) pdu;
1165             mesh_transport_pdu_free(transport_pdu);
1166             break;
1167         case MESH_PDU_TYPE_MESSAGE:
1168             message_pdu = (mesh_message_pdu_t *) pdu;
1169             mesh_message_pdu_free(message_pdu);
1170         default:
1171             break;
1172     }
1173 }
1174 
1175 void mesh_upper_transport_message_processed_by_higher_layer(mesh_pdu_t * pdu){
1176     crypto_active = 0;
1177     switch (pdu->pdu_type){
1178         case MESH_PDU_TYPE_ACCESS:
1179             mesh_upper_transport_process_segmented_access_message_done((mesh_access_pdu_t *) pdu);
1180             break;
1181         case MESH_PDU_TYPE_MESSAGE:
1182             mesh_upper_transport_process_message_done((mesh_message_pdu_t *) pdu);
1183             break;
1184         case MESH_PDU_TYPE_UNSEGMENTED_INCOMING:
1185             mesh_upper_transport_process_unsegmented_message_done(pdu);
1186             break;
1187         default:
1188             btstack_assert(0);
1189             break;
1190     }
1191 }
1192 
1193 void mesh_upper_transport_register_access_message_handler(void (*callback)(mesh_pdu_t *pdu)){
1194     mesh_access_message_handler = callback;
1195 }
1196 
1197 void mesh_upper_transport_register_control_message_handler(void (*callback)(mesh_pdu_t *pdu)){
1198     mesh_control_message_handler = callback;
1199 }
1200 
1201 void mesh_upper_transport_set_higher_layer_handler(void (*pdu_handler)( mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu)){
1202     higher_layer_handler = pdu_handler;
1203 }
1204 
1205 void mesh_upper_transport_init(){
1206     mesh_lower_transport_set_higher_layer_handler(&mesh_upper_transport_pdu_handler);
1207 }
1208