xref: /btstack/src/mesh/mesh_upper_transport.c (revision e4121a3476252ffaf400cdf7976cac7756511fa4)
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 mesh_upper_transport_validate_segmented_message(void);
75 static void mesh_upper_transport_run(void);
76 
77 static int crypto_active;
78 
79 static mesh_access_pdu_t *      incoming_access_pdu_encrypted;
80 static mesh_access_pdu_t *      incoming_access_pdu_decrypted;
81 
82 static mesh_access_pdu_t        incoming_access_pdu_encrypted_singleton;
83 static mesh_access_pdu_t        incoming_access_pdu_decrypted_singleton;
84 
85 static mesh_control_pdu_t       incoming_control_pdu_singleton;
86 static mesh_control_pdu_t *     incoming_control_pdu;
87 
88 static mesh_segmented_pdu_t         outgoing_segmented_pdu_singleton;
89 static mesh_upper_transport_pdu_t * outgoing_upper_transport_pdu;
90 
91 static uint8_t application_nonce[13];
92 static btstack_crypto_ccm_t ccm;
93 static uint8_t crypto_buffer[MESH_ACCESS_PAYLOAD_MAX];
94 static mesh_transport_key_and_virtual_address_iterator_t mesh_transport_key_it;
95 
96 // upper transport callbacks - in access layer
97 static void (*mesh_access_message_handler)( mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu);
98 static void (*mesh_control_message_handler)( mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu);
99 
100 // incoming unsegmented (network) and segmented (transport) control and access messages
101 static btstack_linked_list_t upper_transport_incoming;
102 
103 // outgoing unsegmented (network) and segmented (uppert_transport_outgoing) control and access messages
104 static btstack_linked_list_t upper_transport_outgoing;
105 
106 
107 // TODO: higher layer define used for assert
108 #define MESH_ACCESS_OPCODE_NOT_SET 0xFFFFFFFEu
109 
110 static void mesh_print_hex(const char * name, const uint8_t * data, uint16_t len){
111     printf("%-20s ", name);
112     printf_hexdump(data, len);
113 }
114 // static void mesh_print_x(const char * name, uint32_t value){
115 //     printf("%20s: 0x%x", name, (int) value);
116 // }
117 
118 static void mesh_transport_key_and_virtual_address_iterator_init(mesh_transport_key_and_virtual_address_iterator_t *it,
119                                                                  uint16_t dst, uint16_t netkey_index, uint8_t akf,
120                                                                  uint8_t aid) {
121     printf("KEY_INIT: dst %04x, akf %x, aid %x\n", dst, akf, aid);
122     // config
123     it->dst   = dst;
124     // init elements
125     it->key     = NULL;
126     it->address = NULL;
127     // init element iterators
128     mesh_transport_key_aid_iterator_init(&it->key_it, netkey_index, akf, aid);
129     // init address iterator
130     if (mesh_network_address_virtual(it->dst)){
131         mesh_virtual_address_iterator_init(&it->address_it, dst);
132         // get first key
133         if (mesh_transport_key_aid_iterator_has_more(&it->key_it)) {
134             it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
135         }
136     }
137 }
138 
139 // cartesian product: keys x addressses
140 static int mesh_transport_key_and_virtual_address_iterator_has_more(mesh_transport_key_and_virtual_address_iterator_t * it){
141     if (mesh_network_address_virtual(it->dst)) {
142         // find next valid entry
143         while (true){
144             if (mesh_virtual_address_iterator_has_more(&it->address_it)) return 1;
145             if (!mesh_transport_key_aid_iterator_has_more(&it->key_it)) return 0;
146             // get next key
147             it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
148             mesh_virtual_address_iterator_init(&it->address_it, it->dst);
149         }
150     } else {
151         return mesh_transport_key_aid_iterator_has_more(&it->key_it);
152     }
153 }
154 
155 static void mesh_transport_key_and_virtual_address_iterator_next(mesh_transport_key_and_virtual_address_iterator_t * it){
156     if (mesh_network_address_virtual(it->dst)) {
157         it->address = mesh_virtual_address_iterator_get_next(&it->address_it);
158     } else {
159         it->key = mesh_transport_key_aid_iterator_get_next(&it->key_it);
160     }
161 }
162 
163 // UPPER TRANSPORT
164 
165 uint16_t mesh_access_dst(mesh_access_pdu_t * access_pdu){
166     return big_endian_read_16(access_pdu->network_header, 7);
167 }
168 
169 uint16_t mesh_access_ctl(mesh_access_pdu_t * access_pdu){
170     return access_pdu->network_header[1] >> 7;
171 }
172 
173 uint32_t mesh_access_seq(mesh_access_pdu_t * access_pdu){
174     return big_endian_read_24(access_pdu->network_header, 2);
175 }
176 
177 void mesh_access_set_nid_ivi(mesh_access_pdu_t * access_pdu, uint8_t nid_ivi){
178     access_pdu->network_header[0] = nid_ivi;
179 }
180 void mesh_access_set_ctl_ttl(mesh_access_pdu_t * access_pdu, uint8_t ctl_ttl){
181     access_pdu->network_header[1] = ctl_ttl;
182 }
183 void mesh_access_set_seq(mesh_access_pdu_t * access_pdu, uint32_t seq){
184     big_endian_store_24(access_pdu->network_header, 2, seq);
185 }
186 void mesh_access_set_src(mesh_access_pdu_t * access_pdu, uint16_t src){
187     big_endian_store_16(access_pdu->network_header, 5, src);
188 }
189 void mesh_access_set_dest(mesh_access_pdu_t * access_pdu, uint16_t dest){
190     big_endian_store_16(access_pdu->network_header, 7, dest);
191 }
192 
193 static void mesh_segmented_pdu_flatten(btstack_linked_list_t * segments, uint8_t segment_len, uint8_t * buffer) {
194     // assemble payload
195     btstack_linked_list_iterator_t it;
196     btstack_linked_list_iterator_init(&it, segments);
197     while (btstack_linked_list_iterator_has_next(&it)) {
198         mesh_network_pdu_t *segment = (mesh_network_pdu_t *) btstack_linked_list_iterator_next(&it);
199         btstack_assert(segment->pdu_header.pdu_type == MESH_PDU_TYPE_NETWORK);
200         // get segment n
201         uint8_t *lower_transport_pdu = mesh_network_pdu_data(segment);
202         uint8_t seg_o = (big_endian_read_16(lower_transport_pdu, 2) >> 5) & 0x001f;
203         uint8_t *segment_data = &lower_transport_pdu[4];
204         (void) memcpy(&buffer[seg_o * segment_len], segment_data, segment_len);
205     }
206 }
207 
208 static uint16_t mesh_upper_pdu_flatten(mesh_upper_transport_pdu_t * upper_pdu, uint8_t * buffer, uint16_t buffer_len) {
209     // assemble payload
210     btstack_linked_list_iterator_t it;
211     btstack_linked_list_iterator_init(&it, &upper_pdu->segments);
212     uint16_t offset = 0;
213     while (btstack_linked_list_iterator_has_next(&it)) {
214         mesh_network_pdu_t *segment = (mesh_network_pdu_t *) btstack_linked_list_iterator_next(&it);
215         btstack_assert(segment->pdu_header.pdu_type == MESH_PDU_TYPE_NETWORK);
216         btstack_assert((offset + segment->len) <= buffer_len);
217         (void) memcpy(&buffer[offset], segment->data, segment->len);
218         offset += segment->len;
219     }
220     return offset;
221 }
222 
223 static void mesh_segmented_append_payload(const uint8_t * payload, uint16_t payload_len, btstack_linked_list_t * segments){
224     uint16_t payload_offset = 0;
225     uint16_t bytes_current_segment = 0;
226     mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_get_last_item(segments);
227     if (network_pdu){
228         bytes_current_segment = MESH_NETWORK_PAYLOAD_MAX - network_pdu->len;
229     }
230     while (payload_offset < payload_len){
231         if (bytes_current_segment == 0){
232             network_pdu = mesh_network_pdu_get();
233             btstack_assert(network_pdu != NULL);
234             btstack_linked_list_add_tail(segments, (btstack_linked_item_t *) network_pdu);
235             bytes_current_segment = MESH_NETWORK_PAYLOAD_MAX;
236         }
237         uint16_t bytes_to_copy = btstack_min(bytes_current_segment, payload_len - payload_offset);
238         (void) memcpy(&network_pdu->data[network_pdu->len], &payload[payload_offset], bytes_to_copy);
239         bytes_current_segment -= bytes_to_copy;
240         network_pdu->len += bytes_to_copy;
241         payload_offset += bytes_to_copy;
242     }
243 }
244 
245 // stub lower transport
246 
247 static void mesh_upper_transport_dump_pdus(const char *name, btstack_linked_list_t *list){
248     printf("List: %s:\n", name);
249     btstack_linked_list_iterator_t it;
250     btstack_linked_list_iterator_init(&it, list);
251     while (btstack_linked_list_iterator_has_next(&it)){
252         mesh_pdu_t * pdu = (mesh_pdu_t*) btstack_linked_list_iterator_next(&it);
253         printf("- %p\n", pdu);
254         // printf_hexdump( mesh_pdu_data(pdu), mesh_pdu_len(pdu));
255     }
256 }
257 
258 static void mesh_upper_transport_reset_pdus(btstack_linked_list_t *list){
259     while (!btstack_linked_list_empty(list)){
260         mesh_upper_transport_pdu_free((mesh_pdu_t *) btstack_linked_list_pop(list));
261     }
262 }
263 
264 void mesh_upper_transport_dump(void){
265     mesh_upper_transport_dump_pdus("upper_transport_incoming", &upper_transport_incoming);
266 }
267 
268 void mesh_upper_transport_reset(void){
269     crypto_active = 0;
270     outgoing_upper_transport_pdu = NULL;
271     mesh_upper_transport_reset_pdus(&upper_transport_incoming);
272 }
273 
274 static mesh_transport_key_t * mesh_upper_transport_get_outgoing_appkey(uint16_t netkey_index, uint16_t appkey_index){
275     // Device Key is fixed
276     if (appkey_index == MESH_DEVICE_KEY_INDEX) {
277         return mesh_transport_key_get(appkey_index);
278     }
279 
280     // Get key refresh state from subnet
281     mesh_subnet_t * subnet = mesh_subnet_get_by_netkey_index(netkey_index);
282     if (subnet == NULL) return NULL;
283 
284     // identify old and new app keys for given appkey_index
285     mesh_transport_key_t * old_key = NULL;
286     mesh_transport_key_t * new_key = NULL;
287     mesh_transport_key_iterator_t it;
288     mesh_transport_key_iterator_init(&it, netkey_index);
289     while (mesh_transport_key_iterator_has_more(&it)){
290         mesh_transport_key_t * transport_key = mesh_transport_key_iterator_get_next(&it);
291         if (transport_key->appkey_index != appkey_index) continue;
292         if (transport_key->old_key == 0) {
293             new_key = transport_key;
294         } else {
295             old_key = transport_key;
296         }
297     }
298 
299     // if no key is marked as old, just use the current one
300     if (old_key == NULL) return new_key;
301 
302     // use new key if it exists in phase two
303     if ((subnet->key_refresh == MESH_KEY_REFRESH_SECOND_PHASE) && (new_key != NULL)){
304         return new_key;
305     } else {
306         return old_key;
307     }
308 }
309 
310 static uint32_t iv_index_for_ivi_nid(uint8_t ivi_nid){
311     // get IV Index and IVI
312     uint32_t iv_index = mesh_get_iv_index();
313     int ivi = ivi_nid >> 7;
314 
315     // if least significant bit differs, use previous IV Index
316     if ((iv_index & 1 ) ^ ivi){
317         iv_index--;
318     }
319     return iv_index;
320 }
321 
322 static void transport_segmented_setup_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
323     mesh_access_pdu_t * access_pdu;
324     mesh_upper_transport_pdu_t * upper_pdu;
325     switch (pdu->pdu_type){
326         case MESH_PDU_TYPE_ACCESS:
327             access_pdu = (mesh_access_pdu_t *) pdu;
328             nonce[1] = access_pdu->transmic_len == 8 ? 0x80 : 0x00;
329             (void)memcpy(&nonce[2], &access_pdu->network_header[2], 7);
330             big_endian_store_32(nonce, 9, iv_index_for_ivi_nid(access_pdu->network_header[0]));
331             break;
332         case MESH_PDU_TYPE_UPPER_SEGMENTED_ACCESS:
333         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
334             upper_pdu = (mesh_upper_transport_pdu_t *) pdu;
335             nonce[1] = upper_pdu->transmic_len == 8 ? 0x80 : 0x00;
336             // 'network header'
337             big_endian_store_24(nonce, 2, upper_pdu->seq);
338             big_endian_store_16(nonce, 5, upper_pdu->src);
339             big_endian_store_16(nonce, 7, upper_pdu->dst);
340             big_endian_store_32(nonce, 9, iv_index_for_ivi_nid(upper_pdu->ivi_nid));
341             break;
342         default:
343             btstack_assert(0);
344             break;
345     }
346 }
347 
348 static void transport_segmented_setup_application_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
349     nonce[0] = 0x01;
350     transport_segmented_setup_nonce(nonce, pdu);
351     mesh_print_hex("AppNonce", nonce, 13);
352 }
353 
354 static void transport_segmented_setup_device_nonce(uint8_t * nonce, const mesh_pdu_t * pdu){
355     nonce[0] = 0x02;
356     transport_segmented_setup_nonce(nonce, pdu);
357     mesh_print_hex("DeviceNonce", nonce, 13);
358 }
359 
360 static void mesh_upper_transport_process_access_message_done(mesh_access_pdu_t *access_pdu){
361     crypto_active = 0;
362     btstack_assert(mesh_access_ctl(access_pdu) == 0);
363     incoming_access_pdu_encrypted = NULL;
364     mesh_upper_transport_run();
365 }
366 
367 static void mesh_upper_transport_process_control_message_done(mesh_control_pdu_t * control_pdu){
368     crypto_active = 0;
369     incoming_control_pdu = NULL;
370     mesh_upper_transport_run();
371 }
372 
373 static void mesh_upper_transport_validate_segmented_message_ccm(void * arg){
374     UNUSED(arg);
375 
376     uint8_t * upper_transport_pdu     = incoming_access_pdu_decrypted->data;
377     uint8_t   upper_transport_pdu_len = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
378 
379     mesh_print_hex("Decrypted PDU", upper_transport_pdu, upper_transport_pdu_len);
380 
381     // store TransMIC
382     uint8_t trans_mic[8];
383     btstack_crypto_ccm_get_authentication_value(&ccm, trans_mic);
384     mesh_print_hex("TransMIC", trans_mic, incoming_access_pdu_decrypted->transmic_len);
385 
386     if (memcmp(trans_mic, &upper_transport_pdu[upper_transport_pdu_len], incoming_access_pdu_decrypted->transmic_len) == 0){
387         printf("TransMIC matches\n");
388 
389         // remove TransMIC from payload
390         incoming_access_pdu_decrypted->len -= incoming_access_pdu_decrypted->transmic_len;
391 
392         // if virtual address, update dst to pseudo_dst
393         if (mesh_network_address_virtual(mesh_access_dst(incoming_access_pdu_decrypted))){
394             big_endian_store_16(incoming_access_pdu_decrypted->network_header, 7, mesh_transport_key_it.address->pseudo_dst);
395         }
396 
397         // pass to upper layer
398         btstack_assert(mesh_access_message_handler != NULL);
399         mesh_pdu_t * pdu = (mesh_pdu_t*) incoming_access_pdu_decrypted;
400         mesh_access_message_handler(MESH_TRANSPORT_PDU_RECEIVED, MESH_TRANSPORT_STATUS_SUCCESS, pdu);
401 
402         printf("\n");
403 
404     } else {
405         uint8_t akf = incoming_access_pdu_decrypted->akf_aid_control & 0x40;
406         if (akf){
407             printf("TransMIC does not match, try next key\n");
408             mesh_upper_transport_validate_segmented_message();
409         } else {
410             printf("TransMIC does not match device key, done\n");
411             // done
412             mesh_upper_transport_process_access_message_done(incoming_access_pdu_decrypted);
413         }
414     }
415 }
416 
417 static void mesh_upper_transport_validate_segmented_message_digest(void * arg){
418     UNUSED(arg);
419     uint8_t   upper_transport_pdu_len      = incoming_access_pdu_encrypted->len - incoming_access_pdu_encrypted->transmic_len;
420     uint8_t * upper_transport_pdu_data_in  = incoming_access_pdu_encrypted->data;
421     uint8_t * upper_transport_pdu_data_out = incoming_access_pdu_decrypted->data;
422     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);
423 }
424 
425 static void mesh_upper_transport_validate_segmented_message(void){
426     uint8_t * upper_transport_pdu_data =  incoming_access_pdu_decrypted->data;
427     uint8_t   upper_transport_pdu_len  = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
428 
429     if (!mesh_transport_key_and_virtual_address_iterator_has_more(&mesh_transport_key_it)){
430         printf("No valid transport key found\n");
431         mesh_upper_transport_process_access_message_done(incoming_access_pdu_decrypted);
432         return;
433     }
434     mesh_transport_key_and_virtual_address_iterator_next(&mesh_transport_key_it);
435     const mesh_transport_key_t * message_key = mesh_transport_key_it.key;
436 
437     if (message_key->akf){
438         transport_segmented_setup_application_nonce(application_nonce, (mesh_pdu_t *) incoming_access_pdu_encrypted);
439     } else {
440         transport_segmented_setup_device_nonce(application_nonce, (mesh_pdu_t *) incoming_access_pdu_encrypted);
441     }
442 
443     // store application / device key index
444     mesh_print_hex("AppOrDevKey", message_key->key, 16);
445     incoming_access_pdu_decrypted->appkey_index = message_key->appkey_index;
446 
447     mesh_print_hex("EncAccessPayload", upper_transport_pdu_data, upper_transport_pdu_len);
448 
449     // decrypt ccm
450     crypto_active = 1;
451     uint16_t aad_len  = 0;
452     if (mesh_network_address_virtual(mesh_access_dst(incoming_access_pdu_decrypted))){
453         aad_len  = 16;
454     }
455     btstack_crypto_ccm_init(&ccm, message_key->key, application_nonce, upper_transport_pdu_len, aad_len, incoming_access_pdu_decrypted->transmic_len);
456 
457     if (aad_len){
458         btstack_crypto_ccm_digest(&ccm, (uint8_t *) mesh_transport_key_it.address->label_uuid, aad_len, &mesh_upper_transport_validate_segmented_message_digest, NULL);
459     } else {
460         mesh_upper_transport_validate_segmented_message_digest(NULL);
461     }
462 }
463 
464 static void mesh_upper_transport_process_segmented_message(void){
465     // copy original pdu
466     (void)memcpy(incoming_access_pdu_decrypted, incoming_access_pdu_encrypted,
467                  sizeof(mesh_access_pdu_t));
468 
469     //
470     uint8_t * upper_transport_pdu     =  incoming_access_pdu_decrypted->data;
471     uint8_t   upper_transport_pdu_len = incoming_access_pdu_decrypted->len - incoming_access_pdu_decrypted->transmic_len;
472     mesh_print_hex("Upper Transport pdu", upper_transport_pdu, upper_transport_pdu_len);
473 
474     uint8_t aid = incoming_access_pdu_decrypted->akf_aid_control & 0x3f;
475     uint8_t akf = (incoming_access_pdu_decrypted->akf_aid_control & 0x40) >> 6;
476 
477     printf("AKF: %u\n",   akf);
478     printf("AID: %02x\n", aid);
479 
480     mesh_transport_key_and_virtual_address_iterator_init(&mesh_transport_key_it, mesh_access_dst(incoming_access_pdu_decrypted),
481                                                          incoming_access_pdu_decrypted->netkey_index, akf, aid);
482     mesh_upper_transport_validate_segmented_message();
483 }
484 
485 static void mesh_upper_transport_message_received(mesh_pdu_t * pdu){
486     btstack_linked_list_add_tail(&upper_transport_incoming, (btstack_linked_item_t*) pdu);
487     mesh_upper_transport_run();
488 }
489 
490 static void mesh_upper_transport_send_access_segmented(mesh_upper_transport_pdu_t * upper_pdu){
491 
492     // TODO: store upper pdu in outgoing pdus active or similar
493     outgoing_upper_transport_pdu = upper_pdu;
494 
495     mesh_segmented_pdu_t * message_pdu   = &outgoing_segmented_pdu_singleton;
496     message_pdu->pdu_header.pdu_type = MESH_PDU_TYPE_SEGMENTED;
497 
498     // convert mesh_access_pdu_t into mesh_segmented_pdu_t
499     mesh_segmented_append_payload(crypto_buffer, upper_pdu->len, &message_pdu->segments);
500 
501     // copy meta
502     message_pdu->len = upper_pdu->len;
503     message_pdu->netkey_index = upper_pdu->netkey_index;
504     message_pdu->transmic_len = upper_pdu->transmic_len;
505     message_pdu->akf_aid_control = upper_pdu->akf_aid_control;
506     message_pdu->flags = upper_pdu->flags;
507 
508     // setup message_pdu header
509     // (void)memcpy(message_pdu->network_header, upper_pdu->network_header, 9);
510     // TODO: use fields in mesh_segmented_pdu_t and setup network header in lower transport
511     message_pdu->network_header[0] = upper_pdu->ivi_nid;
512     message_pdu->network_header[1] = upper_pdu->ctl_ttl;
513     big_endian_store_24(message_pdu->network_header, 2, upper_pdu->seq);
514     big_endian_store_16(message_pdu->network_header, 5, upper_pdu->src);
515     big_endian_store_16(message_pdu->network_header, 7, upper_pdu->dst);
516 
517     mesh_lower_transport_send_pdu((mesh_pdu_t*) message_pdu);
518 }
519 
520 static void mesh_upper_transport_send_access_unsegmented(mesh_upper_transport_pdu_t * upper_pdu){
521 
522     // TODO: store upper pdu in outgoing pdus active or similar
523     outgoing_upper_transport_pdu = upper_pdu;
524 
525     // provide segment
526     mesh_network_pdu_t * network_pdu = mesh_network_pdu_get();
527     btstack_assert(network_pdu);
528 
529     // setup network pdu
530     network_pdu->pdu_header.pdu_type = MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS;
531     network_pdu->data[0] = upper_pdu->ivi_nid;
532     network_pdu->data[1] = upper_pdu->ctl_ttl;
533     big_endian_store_24(network_pdu->data, 2, upper_pdu->seq);
534     big_endian_store_16(network_pdu->data, 5, upper_pdu->src);
535     big_endian_store_16(network_pdu->data, 7, upper_pdu->dst);
536     network_pdu->netkey_index = upper_pdu->netkey_index;
537 
538     // setup access message
539     network_pdu->data[9] = upper_pdu->akf_aid_control;
540     btstack_assert(upper_pdu->len < 15);
541     (void)memcpy(&network_pdu->data[10], crypto_buffer, upper_pdu->len);
542     network_pdu->len = 10 + upper_pdu->len;
543     network_pdu->flags = 0;
544 
545     mesh_lower_transport_send_pdu((mesh_pdu_t*) network_pdu);
546 }
547 
548 static void mesh_upper_transport_send_access_ccm(void * arg){
549     crypto_active = 0;
550 
551     mesh_upper_transport_pdu_t * upper_pdu = (mesh_upper_transport_pdu_t *) arg;
552     mesh_print_hex("EncAccessPayload", crypto_buffer, upper_pdu->len);
553     // store TransMIC
554     btstack_crypto_ccm_get_authentication_value(&ccm, &crypto_buffer[upper_pdu->len]);
555     mesh_print_hex("TransMIC", &crypto_buffer[upper_pdu->len], upper_pdu->transmic_len);
556     upper_pdu->len += upper_pdu->transmic_len;
557     mesh_print_hex("UpperTransportPDU", crypto_buffer, upper_pdu->len);
558     switch (upper_pdu->pdu_header.pdu_type){
559         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
560             mesh_upper_transport_send_access_unsegmented(upper_pdu);
561             break;
562         case MESH_PDU_TYPE_UPPER_SEGMENTED_ACCESS:
563             mesh_upper_transport_send_access_segmented(upper_pdu);
564             break;
565         default:
566             btstack_assert(false);
567     }
568 }
569 
570 static void mesh_upper_transport_send_access_digest(void *arg){
571     mesh_upper_transport_pdu_t * upper_pdu = (mesh_upper_transport_pdu_t *) arg;
572     uint16_t  access_pdu_len  = upper_pdu->len;
573     btstack_crypto_ccm_encrypt_block(&ccm, access_pdu_len, crypto_buffer, crypto_buffer,
574                                      &mesh_upper_transport_send_access_ccm, upper_pdu);
575 }
576 
577 static void mesh_upper_transport_send_access(mesh_upper_transport_pdu_t * upper_pdu){
578 
579     // if dst is virtual address, lookup label uuid and hash
580     uint16_t aad_len = 0;
581     mesh_virtual_address_t * virtual_address = NULL;
582     if (mesh_network_address_virtual(upper_pdu->dst)){
583         virtual_address = mesh_virtual_address_for_pseudo_dst(upper_pdu->dst);
584         if (!virtual_address){
585             printf("No virtual address register for pseudo dst %4x\n", upper_pdu->dst);
586             mesh_access_message_handler(MESH_TRANSPORT_PDU_SENT, MESH_TRANSPORT_STATUS_SEND_FAILED, (mesh_pdu_t *) upper_pdu);
587             return;
588         }
589         // printf("Using hash %4x with LabelUUID: ", virtual_address->hash);
590         // printf_hexdump(virtual_address->label_uuid, 16);
591         aad_len = 16;
592         upper_pdu->dst = virtual_address->hash;
593     }
594 
595     // get app or device key
596     uint16_t appkey_index = upper_pdu->appkey_index;
597     const mesh_transport_key_t * appkey = mesh_upper_transport_get_outgoing_appkey(upper_pdu->netkey_index, appkey_index);
598     if (appkey == NULL){
599         printf("AppKey %04x not found, drop message\n", appkey_index);
600         mesh_access_message_handler(MESH_TRANSPORT_PDU_SENT, MESH_TRANSPORT_STATUS_SEND_FAILED, (mesh_pdu_t *) upper_pdu);
601         return;
602     }
603 
604     // reserve slot
605     mesh_lower_transport_reserve_slot();
606 
607     // reserve one sequence number, which is also used to encrypt access payload
608     uint32_t seq = mesh_sequence_number_next();
609     upper_pdu->flags |= MESH_TRANSPORT_FLAG_SEQ_RESERVED;
610     upper_pdu->seq = seq;
611 
612     // also reserves crypto_buffer
613     crypto_active = 1;
614 
615     // flatten segmented pdu into crypto buffer
616     uint16_t payload_len = mesh_upper_pdu_flatten(upper_pdu, crypto_buffer, sizeof(crypto_buffer));
617     btstack_assert(payload_len == upper_pdu->len);
618 
619     // Dump PDU
620     printf("[+] Upper transport, send upper (un)segmented Access PDU - dest %04x, seq %06x\n", upper_pdu->dst, upper_pdu->seq);
621     mesh_print_hex("Access Payload", crypto_buffer, upper_pdu->len);
622 
623     // setup nonce - uses dst, so after pseudo address translation
624     if (appkey_index == MESH_DEVICE_KEY_INDEX){
625         transport_segmented_setup_device_nonce(application_nonce, (mesh_pdu_t *) upper_pdu);
626     } else {
627         transport_segmented_setup_application_nonce(application_nonce, (mesh_pdu_t *) upper_pdu);
628     }
629 
630     // Dump key
631     mesh_print_hex("AppOrDevKey", appkey->key, 16);
632 
633     // encrypt ccm
634     uint8_t   transmic_len    = upper_pdu->transmic_len;
635     uint16_t  access_pdu_len  = upper_pdu->len;
636     btstack_crypto_ccm_init(&ccm, appkey->key, application_nonce, access_pdu_len, aad_len, transmic_len);
637     if (virtual_address){
638         mesh_print_hex("LabelUUID", virtual_address->label_uuid, 16);
639         btstack_crypto_ccm_digest(&ccm, virtual_address->label_uuid, 16,
640                                   &mesh_upper_transport_send_access_digest, upper_pdu);
641     } else {
642         mesh_upper_transport_send_access_digest(upper_pdu);
643     }
644 }
645 
646 static void mesh_upper_transport_send_unsegmented_control_pdu(mesh_network_pdu_t * network_pdu){
647     // reserve slot
648     mesh_lower_transport_reserve_slot();
649     // reserve sequence number
650     uint32_t seq = mesh_sequence_number_next();
651     mesh_network_pdu_set_seq(network_pdu, seq);
652     // Dump PDU
653     uint8_t opcode = network_pdu->data[9];
654     printf("[+] Upper transport, send unsegmented Control PDU %p - seq %06x opcode %02x\n", network_pdu, seq, opcode);
655     mesh_print_hex("Access Payload", &network_pdu->data[10], network_pdu->len - 10);
656 
657     // send
658      mesh_lower_transport_send_pdu((mesh_pdu_t *) network_pdu);
659 }
660 
661 static void mesh_upper_transport_send_segmented_control_pdu(mesh_upper_transport_pdu_t * upper_pdu){
662     // reserve slot
663     mesh_lower_transport_reserve_slot();
664     // reserve sequence number
665     uint32_t seq = mesh_sequence_number_next();
666     upper_pdu->flags |= MESH_TRANSPORT_FLAG_SEQ_RESERVED;
667     upper_pdu->seq = seq;
668     // Dump PDU
669     // uint8_t opcode = upper_pdu->data[0];
670     // printf("[+] Upper transport, send segmented Control PDU %p - seq %06x opcode %02x\n", upper_pdu, seq, opcode);
671     // mesh_print_hex("Access Payload", &upper_pdu->data[1], upper_pdu->len - 1);
672     // send
673     outgoing_upper_transport_pdu = upper_pdu;
674     mesh_segmented_pdu_t *messagePdu = &outgoing_segmented_pdu_singleton;
675     messagePdu->pdu_header.pdu_type = MESH_PDU_TYPE_SEGMENTED;
676 
677     // lend segments to lower transport pdu
678     messagePdu->segments = upper_pdu->segments;
679     upper_pdu->segments = NULL;
680 
681     // copy meta
682     messagePdu->len = upper_pdu->len;
683     messagePdu->netkey_index = upper_pdu->netkey_index;
684     messagePdu->transmic_len = 0;   // no TransMIC for control
685     messagePdu->akf_aid_control = upper_pdu->akf_aid_control;
686     messagePdu->flags = upper_pdu->flags;
687 
688     // setup message_pdu header
689     // TODO: use fields in mesh_segmented_pdu_t and setup network header in lower transport
690     messagePdu->network_header[0] = upper_pdu->ivi_nid;
691     messagePdu->network_header[1] = upper_pdu->ctl_ttl;
692     big_endian_store_24(messagePdu->network_header, 2, upper_pdu->seq);
693     big_endian_store_16(messagePdu->network_header, 5, upper_pdu->src);
694     big_endian_store_16(messagePdu->network_header, 7, upper_pdu->dst);
695 
696     mesh_lower_transport_send_pdu((mesh_pdu_t *) messagePdu);
697 }
698 
699 static void mesh_upper_transport_run(void){
700 
701     while(!btstack_linked_list_empty(&upper_transport_incoming)){
702 
703         if (crypto_active) return;
704 
705         // get next message
706         mesh_pdu_t * pdu =  (mesh_pdu_t *) btstack_linked_list_pop(&upper_transport_incoming);
707         mesh_network_pdu_t   * network_pdu;
708         mesh_segmented_pdu_t   * message_pdu;
709         switch (pdu->pdu_type){
710             case MESH_PDU_TYPE_UNSEGMENTED:
711                 network_pdu = (mesh_network_pdu_t *) pdu;
712                 // control?
713                 if (mesh_network_control(network_pdu)) {
714 
715                     incoming_control_pdu =  &incoming_control_pdu_singleton;
716                     incoming_control_pdu->pdu_header.pdu_type = MESH_PDU_TYPE_CONTROL;
717                     incoming_control_pdu->len =  network_pdu->len;
718                     incoming_control_pdu->netkey_index =  network_pdu->netkey_index;
719 
720                     uint8_t * lower_transport_pdu = mesh_network_pdu_data(network_pdu);
721 
722                     incoming_control_pdu->akf_aid_control = lower_transport_pdu[0];
723                     incoming_control_pdu->len = network_pdu->len - 10; // 9 header + 1 opcode
724                     (void)memcpy(incoming_control_pdu->data, &lower_transport_pdu[1], incoming_control_pdu->len);
725 
726                     // copy meta data into encrypted pdu buffer
727                     (void)memcpy(incoming_control_pdu->network_header, network_pdu->data, 9);
728 
729                     mesh_print_hex("Assembled payload", incoming_control_pdu->data, incoming_control_pdu->len);
730 
731                     // free mesh message
732                     mesh_lower_transport_message_processed_by_higher_layer(pdu);
733 
734                     btstack_assert(mesh_control_message_handler != NULL);
735                     mesh_pdu_t * pdu = (mesh_pdu_t*) incoming_control_pdu;
736                     mesh_control_message_handler(MESH_TRANSPORT_PDU_RECEIVED, MESH_TRANSPORT_STATUS_SUCCESS, pdu);
737 
738                 } else {
739 
740                     incoming_access_pdu_encrypted = &incoming_access_pdu_encrypted_singleton;
741                     incoming_access_pdu_encrypted->pdu_header.pdu_type = MESH_PDU_TYPE_ACCESS;
742                     incoming_access_pdu_decrypted = &incoming_access_pdu_decrypted_singleton;
743 
744                     incoming_access_pdu_encrypted->netkey_index = network_pdu->netkey_index;
745                     incoming_access_pdu_encrypted->transmic_len = 4;
746 
747                     uint8_t * lower_transport_pdu = mesh_network_pdu_data(network_pdu);
748 
749                     incoming_access_pdu_encrypted->akf_aid_control = lower_transport_pdu[0];
750                     incoming_access_pdu_encrypted->len = network_pdu->len - 10; // 9 header + 1 AID
751                     (void)memcpy(incoming_access_pdu_encrypted->data, &lower_transport_pdu[1], incoming_access_pdu_encrypted->len);
752 
753                     // copy meta data into encrypted pdu buffer
754                     (void)memcpy(incoming_access_pdu_encrypted->network_header, network_pdu->data, 9);
755 
756                     mesh_print_hex("Assembled payload", incoming_access_pdu_encrypted->data, incoming_access_pdu_encrypted->len);
757 
758                     // free mesh message
759                     mesh_lower_transport_message_processed_by_higher_layer(pdu);
760 
761                     // get encoded transport pdu and start processing
762                     mesh_upper_transport_process_segmented_message();
763                 }
764                 break;
765             case MESH_PDU_TYPE_SEGMENTED:
766                 message_pdu = (mesh_segmented_pdu_t *) pdu;
767                 uint8_t ctl = mesh_message_ctl(message_pdu);
768                 if (ctl){
769                     incoming_control_pdu=  &incoming_control_pdu_singleton;
770                     incoming_control_pdu->pdu_header.pdu_type = MESH_PDU_TYPE_CONTROL;
771 
772                     // flatten
773                     mesh_segmented_pdu_flatten(&message_pdu->segments, 8, incoming_control_pdu->data);
774 
775                     // copy meta data into encrypted pdu buffer
776                     incoming_control_pdu->len =  message_pdu->len;
777                     incoming_control_pdu->netkey_index =  message_pdu->netkey_index;
778                     incoming_control_pdu->akf_aid_control =  message_pdu->akf_aid_control;
779                     incoming_control_pdu->flags = 0;
780                     (void)memcpy(incoming_control_pdu->network_header, message_pdu->network_header, 9);
781 
782                     mesh_print_hex("Assembled payload", incoming_control_pdu->data, incoming_control_pdu->len);
783 
784                     // free mesh message
785                     mesh_lower_transport_message_processed_by_higher_layer((mesh_pdu_t *)message_pdu);
786 
787                     btstack_assert(mesh_control_message_handler != NULL);
788                     mesh_pdu_t * pdu = (mesh_pdu_t*) incoming_control_pdu;
789                     mesh_access_message_handler(MESH_TRANSPORT_PDU_RECEIVED, MESH_TRANSPORT_STATUS_SUCCESS, pdu);
790 
791                 } else {
792 
793                     incoming_access_pdu_encrypted = &incoming_access_pdu_encrypted_singleton;
794                     incoming_access_pdu_encrypted->pdu_header.pdu_type = MESH_PDU_TYPE_ACCESS;
795                     incoming_access_pdu_decrypted = &incoming_access_pdu_decrypted_singleton;
796 
797                     // flatten
798                     mesh_segmented_pdu_flatten(&message_pdu->segments, 12, incoming_access_pdu_encrypted->data);
799 
800                     // copy meta data into encrypted pdu buffer
801                     incoming_access_pdu_encrypted->len =  message_pdu->len;
802                     incoming_access_pdu_encrypted->netkey_index =  message_pdu->netkey_index;
803                     incoming_access_pdu_encrypted->transmic_len =  message_pdu->transmic_len;
804                     incoming_access_pdu_encrypted->akf_aid_control =  message_pdu->akf_aid_control;
805                     (void)memcpy(incoming_access_pdu_encrypted->network_header, message_pdu->network_header, 9);
806 
807                     mesh_print_hex("Assembled payload", incoming_access_pdu_encrypted->data, incoming_access_pdu_encrypted->len);
808 
809                     // free mesh message
810                     mesh_lower_transport_message_processed_by_higher_layer((mesh_pdu_t *)message_pdu);
811 
812                     // get encoded transport pdu and start processing
813                     mesh_upper_transport_process_segmented_message();
814                 }
815                 break;
816             default:
817                 btstack_assert(0);
818                 break;
819         }
820     }
821 
822     while (!btstack_linked_list_empty(&upper_transport_outgoing)){
823 
824         if (crypto_active) break;
825 
826         if (outgoing_upper_transport_pdu != NULL) break;
827 
828         mesh_pdu_t * pdu =  (mesh_pdu_t *) btstack_linked_list_get_first_item(&upper_transport_outgoing);
829         if (mesh_lower_transport_can_send_to_dest(mesh_pdu_dst(pdu)) == 0) break;
830 
831         (void) btstack_linked_list_pop(&upper_transport_outgoing);
832 
833 
834         switch (pdu->pdu_type){
835             case MESH_PDU_TYPE_UPPER_UNSEGMENTED_CONTROL:
836                 btstack_assert(mesh_pdu_ctl(pdu) != 0);
837                 mesh_upper_transport_send_unsegmented_control_pdu((mesh_network_pdu_t *) pdu);
838                 break;
839             case MESH_PDU_TYPE_UPPER_SEGMENTED_CONTROL:
840                 mesh_upper_transport_send_segmented_control_pdu((mesh_upper_transport_pdu_t *) pdu);
841                 break;
842             case MESH_PDU_TYPE_UPPER_SEGMENTED_ACCESS:
843             case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
844                 mesh_upper_transport_send_access((mesh_upper_transport_pdu_t *) pdu);
845                 break;
846             default:
847                 btstack_assert(false);
848                 break;
849         }
850     }
851 }
852 
853 static void mesh_upper_transport_pdu_handler(mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu){
854     mesh_pdu_t * pdu_to_report;
855     mesh_upper_transport_pdu_t * upper_pdu;
856     switch (callback_type){
857         case MESH_TRANSPORT_PDU_RECEIVED:
858             mesh_upper_transport_message_received(pdu);
859             break;
860         case MESH_TRANSPORT_PDU_SENT:
861             switch (pdu->pdu_type){
862                 case MESH_PDU_TYPE_SEGMENTED:
863                     // free chunks
864                     while (!btstack_linked_list_empty(&outgoing_segmented_pdu_singleton.segments)){
865                         mesh_network_pdu_t * network_pdu = (mesh_network_pdu_t *) btstack_linked_list_pop(&outgoing_segmented_pdu_singleton.segments);
866                         mesh_network_pdu_free(network_pdu);
867                     }
868                     // notify upper layer but use transport pdu
869                     pdu_to_report = (mesh_pdu_t *) outgoing_upper_transport_pdu;
870                     outgoing_upper_transport_pdu = NULL;
871                     if (mesh_pdu_ctl(pdu_to_report)){
872                         mesh_control_message_handler(callback_type, status, pdu_to_report);
873                     } else {
874                         mesh_access_message_handler(callback_type, status, pdu_to_report);
875                     }
876                     break;
877                 case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
878                     upper_pdu = outgoing_upper_transport_pdu;
879                     outgoing_upper_transport_pdu = NULL;
880                     mesh_access_message_handler(callback_type, status, (mesh_pdu_t*) upper_pdu);
881                     break;
882                 case MESH_PDU_TYPE_UPPER_UNSEGMENTED_CONTROL:
883                     mesh_access_message_handler(callback_type, status, pdu);
884                     break;
885                 default:
886                     btstack_assert(false);
887                     break;
888             }
889             mesh_upper_transport_run();
890             break;
891         default:
892             break;
893     }
894 }
895 
896 void mesh_upper_transport_pdu_free(mesh_pdu_t * pdu){
897     mesh_network_pdu_t   * network_pdu;
898     mesh_segmented_pdu_t   * message_pdu;
899     switch (pdu->pdu_type) {
900         case MESH_PDU_TYPE_NETWORK:
901             network_pdu = (mesh_network_pdu_t *) pdu;
902             mesh_network_pdu_free(network_pdu);
903             break;
904         case MESH_PDU_TYPE_SEGMENTED:
905             message_pdu = (mesh_segmented_pdu_t *) pdu;
906             mesh_message_pdu_free(message_pdu);
907         default:
908             btstack_assert(false);
909             break;
910     }
911 }
912 
913 void mesh_upper_transport_message_processed_by_higher_layer(mesh_pdu_t * pdu){
914     crypto_active = 0;
915     switch (pdu->pdu_type){
916         case MESH_PDU_TYPE_ACCESS:
917             mesh_upper_transport_process_access_message_done((mesh_access_pdu_t *) pdu);
918         case MESH_PDU_TYPE_CONTROL:
919             mesh_upper_transport_process_control_message_done((mesh_control_pdu_t *) pdu);
920             break;
921         default:
922             btstack_assert(0);
923             break;
924     }
925 }
926 
927 void mesh_upper_transport_send_access_pdu(mesh_pdu_t *pdu){
928     switch (pdu->pdu_type){
929         case MESH_PDU_TYPE_UPPER_SEGMENTED_ACCESS:
930         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
931             break;
932         default:
933             btstack_assert(false);
934             break;
935     }
936 
937     btstack_linked_list_add_tail(&upper_transport_outgoing, (btstack_linked_item_t*) pdu);
938     mesh_upper_transport_run();
939 }
940 
941 void mesh_upper_transport_send_control_pdu(mesh_pdu_t * pdu){
942     switch (pdu->pdu_type){
943         case MESH_PDU_TYPE_UPPER_SEGMENTED_CONTROL:
944             break;
945         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_CONTROL:
946             btstack_assert( ((mesh_network_pdu_t *) pdu)->len >= 9);
947             break;
948         default:
949             btstack_assert(false);
950             break;
951     }
952 
953     btstack_linked_list_add_tail(&upper_transport_outgoing, (btstack_linked_item_t*) pdu);
954     mesh_upper_transport_run();
955 }
956 
957 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,
958                                                                   const uint8_t * control_pdu_data, uint16_t control_pdu_len){
959 
960     if (control_pdu_len > 11) return 1;
961 
962     const mesh_network_key_t * network_key = mesh_network_key_list_get(netkey_index);
963     if (!network_key) return 1;
964 
965     uint8_t transport_pdu_data[12];
966     transport_pdu_data[0] = opcode;
967     (void)memcpy(&transport_pdu_data[1], control_pdu_data, control_pdu_len);
968     uint16_t transport_pdu_len = control_pdu_len + 1;
969 
970     // setup network_pdu
971     mesh_network_setup_pdu(network_pdu, netkey_index, network_key->nid, 1, ttl, 0, src, dest, transport_pdu_data, transport_pdu_len);
972 
973     return 0;
974 }
975 
976 static uint8_t mesh_upper_transport_setup_segmented_control_pdu(mesh_upper_transport_pdu_t * upper_pdu, uint16_t netkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t opcode,
977                                                                 const uint8_t * control_pdu_data, uint16_t control_pdu_len){
978 
979     if (control_pdu_len > 256) return 1;
980 
981     const mesh_network_key_t * network_key = mesh_network_key_list_get(netkey_index);
982     if (!network_key) return 1;
983 
984     upper_pdu->ivi_nid = network_key->nid | ((mesh_get_iv_index_for_tx() & 1) << 7);
985     upper_pdu->ctl_ttl = ttl;
986     upper_pdu->src = src;
987     upper_pdu->dst = dest;
988     upper_pdu->transmic_len = 0;    // no TransMIC for control
989     upper_pdu->netkey_index = netkey_index;
990     upper_pdu->akf_aid_control = opcode;
991 
992     mesh_segmented_append_payload(control_pdu_data, control_pdu_len, &upper_pdu->segments);
993     upper_pdu->len = control_pdu_len;
994     return 0;
995 }
996 
997 uint8_t mesh_upper_transport_setup_control_pdu(mesh_pdu_t * pdu, uint16_t netkey_index,
998                                                uint8_t ttl, uint16_t src, uint16_t dest, uint8_t opcode, const uint8_t * control_pdu_data, uint16_t control_pdu_len){
999     switch (pdu->pdu_type){
1000         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_CONTROL:
1001             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);
1002         case MESH_PDU_TYPE_UPPER_SEGMENTED_CONTROL:
1003             return mesh_upper_transport_setup_segmented_control_pdu((mesh_upper_transport_pdu_t *) pdu,  netkey_index, ttl, src, dest, opcode, control_pdu_data, control_pdu_len);
1004         default:
1005             btstack_assert(0);
1006             return 1;
1007     }
1008 }
1009 
1010 static uint8_t mesh_upper_transport_setup_segmented_access_pdu_header(mesh_access_pdu_t * access_pdu, uint16_t netkey_index,
1011                                                                       uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic){
1012 
1013     // get app or device key
1014     const mesh_transport_key_t *appkey;
1015     appkey = mesh_transport_key_get(appkey_index);
1016     if (appkey == NULL) {
1017         printf("[!] Upper transport, setup segmented Access PDU - appkey_index %x unknown\n", appkey_index);
1018         return 1;
1019     }
1020     uint8_t akf_aid = (appkey->akf << 6) | appkey->aid;
1021 
1022     // lookup network by netkey_index
1023     const mesh_network_key_t *network_key = mesh_network_key_list_get(netkey_index);
1024     if (!network_key) return 1;
1025     if (network_key == NULL) {
1026         printf("[!] Upper transport, setup segmented Access PDU - netkey_index %x unknown\n", appkey_index);
1027         return 1;
1028     }
1029 
1030     const uint8_t trans_mic_len = szmic ? 8 : 4;
1031 
1032     // store in transport pdu
1033     access_pdu->transmic_len = trans_mic_len;
1034     access_pdu->netkey_index = netkey_index;
1035     access_pdu->appkey_index = appkey_index;
1036     access_pdu->akf_aid_control = akf_aid;
1037     mesh_access_set_nid_ivi(access_pdu, network_key->nid | ((mesh_get_iv_index_for_tx() & 1) << 7));
1038     mesh_access_set_src(access_pdu, src);
1039     mesh_access_set_dest(access_pdu, dest);
1040     mesh_access_set_ctl_ttl(access_pdu, ttl);
1041     return 0;
1042 }
1043 
1044 static uint8_t mesh_upper_transport_setup_upper_access_pdu_header(mesh_upper_transport_pdu_t * upper_pdu, uint16_t netkey_index,
1045                                                                   uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic){
1046 
1047     // get app or device key
1048     const mesh_transport_key_t *appkey;
1049     appkey = mesh_transport_key_get(appkey_index);
1050     if (appkey == NULL) {
1051         printf("[!] Upper transport, setup segmented Access PDU - appkey_index %x unknown\n", appkey_index);
1052         return 1;
1053     }
1054     uint8_t akf_aid = (appkey->akf << 6) | appkey->aid;
1055 
1056     // lookup network by netkey_index
1057     const mesh_network_key_t *network_key = mesh_network_key_list_get(netkey_index);
1058     if (!network_key) return 1;
1059     if (network_key == NULL) {
1060         printf("[!] Upper transport, setup segmented Access PDU - netkey_index %x unknown\n", appkey_index);
1061         return 1;
1062     }
1063 
1064     const uint8_t trans_mic_len = szmic ? 8 : 4;
1065 
1066     // store in transport pdu
1067     upper_pdu->ivi_nid = network_key->nid | ((mesh_get_iv_index_for_tx() & 1) << 7);
1068     upper_pdu->ctl_ttl = ttl;
1069     upper_pdu->src = src;
1070     upper_pdu->dst = dest;
1071     upper_pdu->transmic_len = trans_mic_len;
1072     upper_pdu->netkey_index = netkey_index;
1073     upper_pdu->appkey_index = appkey_index;
1074     upper_pdu->akf_aid_control = akf_aid;
1075     return 0;
1076 }
1077 
1078 static uint8_t mesh_upper_transport_setup_upper_access_pdu(mesh_upper_transport_pdu_t * upper_pdu, uint16_t netkey_index, uint16_t appkey_index, uint8_t ttl, uint16_t src, uint16_t dest,
1079                                                            uint8_t szmic, const uint8_t * access_pdu_data, uint8_t access_pdu_len){
1080     int status = mesh_upper_transport_setup_upper_access_pdu_header(upper_pdu, netkey_index, appkey_index, ttl, src,
1081                                                                     dest, szmic);
1082     if (status) return status;
1083 
1084     // store in transport pdu
1085     mesh_segmented_append_payload(access_pdu_data, access_pdu_len, &upper_pdu->segments);
1086     upper_pdu->len = access_pdu_len;
1087     return 0;
1088 }
1089 
1090 
1091 uint8_t mesh_upper_transport_setup_access_pdu_header(mesh_pdu_t * pdu, uint16_t netkey_index, uint16_t appkey_index,
1092                                                      uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic){
1093     switch (pdu->pdu_type){
1094         case MESH_PDU_TYPE_ACCESS:
1095             return mesh_upper_transport_setup_segmented_access_pdu_header((mesh_access_pdu_t *) pdu, netkey_index, appkey_index, ttl, src, dest, szmic);
1096         default:
1097             btstack_assert(false);
1098             return 1;
1099     }
1100 }
1101 
1102 uint8_t mesh_upper_transport_setup_access_pdu(mesh_pdu_t * pdu, uint16_t netkey_index, uint16_t appkey_index,
1103                                               uint8_t ttl, uint16_t src, uint16_t dest, uint8_t szmic,
1104                                               const uint8_t * access_pdu_data, uint8_t access_pdu_len){
1105     switch (pdu->pdu_type){
1106         case MESH_PDU_TYPE_UPPER_SEGMENTED_ACCESS:
1107         case MESH_PDU_TYPE_UPPER_UNSEGMENTED_ACCESS:
1108             return mesh_upper_transport_setup_upper_access_pdu((mesh_upper_transport_pdu_t *) pdu, netkey_index,
1109                                                                appkey_index, ttl, src, dest, szmic, access_pdu_data,
1110                                                                access_pdu_len);
1111         default:
1112             btstack_assert(false);
1113             return 1;
1114     }
1115 }
1116 
1117 void mesh_upper_transport_register_access_message_handler(void (*callback)(mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu)) {
1118     mesh_access_message_handler = callback;
1119 }
1120 
1121 void mesh_upper_transport_register_control_message_handler(void (*callback)(mesh_transport_callback_type_t callback_type, mesh_transport_status_t status, mesh_pdu_t * pdu)){
1122     mesh_control_message_handler = callback;
1123 }
1124 
1125 void mesh_upper_transport_init(){
1126     mesh_lower_transport_set_higher_layer_handler(&mesh_upper_transport_pdu_handler);
1127 }
1128