xref: /btstack/src/mesh/pb_adv.c (revision 8936a14384360a1b771ab2f993f6a6ac0346f02d)
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__ "pb_adv.c"
39 
40 #include <stdint.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include "mesh/adv_bearer.h"
45 #include "mesh/beacon.h"
46 #include "mesh/mesh_node.h"
47 #include "provisioning.h"
48 #include "btstack_util.h"
49 #include "btstack_debug.h"
50 #include "btstack_event.h"
51 
52 #define PB_ADV_LINK_OPEN_RETRANSMIT_MS 1000
53 
54 static void pb_adv_run(void);
55 
56 /* taps: 32 31 29 1; characteristic polynomial: x^32 + x^31 + x^29 + x + 1 */
57 #define LFSR(a) ((a >> 1) ^ (uint32_t)((0 - (a & 1u)) & 0xd0000001u))
58 
59 // PB-ADV - Provisioning Bearer using Advertisement Bearer
60 
61 #define MESH_GENERIC_PROVISIONING_LINK_OPEN              0x00
62 #define MESH_GENERIC_PROVISIONING_LINK_ACK               0x01
63 #define MESH_GENERIC_PROVISIONING_LINK_CLOSE             0x02
64 
65 #define MESH_GENERIC_PROVISIONING_TRANSACTION_TIMEOUT_MS 30000
66 
67 #define MESH_PB_ADV_MAX_PDU_SIZE  100
68 #define MESH_PB_ADV_MAX_SEGMENTS    8
69 #define MESH_PB_ADV_START_PAYLOAD  20
70 #define MESH_PB_ADV_CONT_PAYLOAD   23
71 
72 typedef enum mesh_gpcf_format {
73     MESH_GPCF_TRANSACTION_START = 0,
74     MESH_GPCF_TRANSACTION_ACK,
75     MESH_GPCF_TRANSACTION_CONT,
76     MESH_GPCF_PROV_BEARER_CONTROL,
77 } mesh_gpcf_format_t;
78 
79 typedef enum {
80     LINK_STATE_W4_OPEN,
81     LINK_STATE_W2_SEND_ACK,
82     LINK_STATE_W4_ACK,
83     LINK_STATE_OPEN,
84     LINK_STATE_CLOSING,
85 } link_state_t;
86 static link_state_t link_state;
87 
88 #ifdef ENABLE_MESH_PROVISIONER
89 static const uint8_t * pb_adv_peer_device_uuid;
90 #endif
91 
92 static uint8_t  pb_adv_msg_in_buffer[MESH_PB_ADV_MAX_PDU_SIZE];   // TODO: how large are prov messages?
93 
94 // single adv link
95 static uint16_t pb_adv_cid = 1;
96 static uint8_t  pb_adv_provisioner_role;
97 
98 // link state
99 static uint32_t pb_adv_link_id;
100 static uint8_t  pb_adv_link_close_reason;
101 static uint8_t  pb_adv_link_close_countdown;
102 
103 // random delay for outgoing packets
104 static uint32_t pb_adv_lfsr;
105 static uint8_t                pb_adv_random_delay_active;
106 static btstack_timer_source_t pb_adv_random_delay_timer;
107 
108 // incoming message
109 static uint8_t  pb_adv_msg_in_transaction_nr_prev;
110 static uint16_t pb_adv_msg_in_len;   //
111 static uint8_t  pb_adv_msg_in_fcs;
112 static uint8_t  pb_adv_msg_in_last_segment;
113 static uint8_t  pb_adv_msg_in_segments_missing; // bitfield for segmentes 1-n
114 static uint8_t  pb_adv_msg_in_transaction_nr;
115 static uint8_t  pb_adv_msg_in_send_ack;
116 
117 // oputgoing message
118 static uint8_t         pb_adv_msg_out_active;
119 static uint8_t         pb_adv_msg_out_transaction_nr;
120 static uint8_t         pb_adv_msg_out_completed_transaction_nr;
121 static uint16_t        pb_adv_msg_out_len;
122 static uint16_t        pb_adv_msg_out_pos;
123 static uint8_t         pb_adv_msg_out_seg;
124 static uint32_t        pb_adv_msg_out_start;
125 static const uint8_t * pb_adv_msg_out_buffer;
126 
127 static btstack_packet_handler_t pb_adv_packet_handler;
128 
129 // poor man's random number generator
130 static uint32_t pb_adv_random(void){
131     pb_adv_lfsr = LFSR(pb_adv_lfsr);
132     return pb_adv_lfsr;
133 }
134 
135 static void pb_adv_emit_pdu_sent(uint8_t status){
136     uint8_t event[] = { HCI_EVENT_MESH_META, 2, MESH_SUBEVENT_PB_TRANSPORT_PDU_SENT, status};
137     pb_adv_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event));
138 }
139 
140 static void pb_adv_emit_link_open(uint8_t status, uint16_t pb_adv_cid){
141     uint8_t event[7] = { HCI_EVENT_MESH_META, 5, MESH_SUBEVENT_PB_TRANSPORT_LINK_OPEN, status};
142     little_endian_store_16(event, 4, pb_adv_cid);
143     event[6] = PB_TYPE_ADV;
144     pb_adv_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event));
145 }
146 
147 static void pb_adv_emit_link_close(uint16_t pb_adv_cid, uint8_t reason){
148     uint8_t event[5] = { HCI_EVENT_MESH_META, 3, MESH_SUBEVENT_PB_TRANSPORT_LINK_CLOSED};
149     little_endian_store_16(event, 4, pb_adv_cid);
150     pb_adv_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event));
151 }
152 
153 static void pb_adv_handle_bearer_control(uint32_t link_id, uint8_t transaction_nr, const uint8_t * pdu, uint16_t size){
154     uint8_t bearer_opcode = pdu[0] >> 2;
155     uint8_t reason;
156     const uint8_t * own_device_uuid;
157     switch (bearer_opcode){
158         case MESH_GENERIC_PROVISIONING_LINK_OPEN: // Open a session on a bearer with a device
159             // does it match our device_uuid?
160             own_device_uuid = mesh_node_get_device_uuid();
161             if (!own_device_uuid) break;
162             if (memcmp(&pdu[1], own_device_uuid, 16) != 0) break;
163             switch(link_state){
164                 case LINK_STATE_W4_OPEN:
165                     pb_adv_link_id = link_id;
166                     pb_adv_provisioner_role = 0;
167                     pb_adv_msg_in_transaction_nr = 0xff;  // first transaction nr will be 0x00
168                     pb_adv_msg_in_transaction_nr_prev = 0xff;
169                     log_info("link open, id %08x", pb_adv_link_id);
170                     printf("PB-ADV: Link Open %08x\n", pb_adv_link_id);
171                     link_state = LINK_STATE_W2_SEND_ACK;
172                     adv_bearer_request_can_send_now_for_provisioning_pdu();
173                     pb_adv_emit_link_open(0, pb_adv_cid);
174                     break;
175                 case LINK_STATE_OPEN:
176                     if (pb_adv_link_id != link_id) break;
177                     log_info("link open, resend ACK");
178                     link_state = LINK_STATE_W2_SEND_ACK;
179                     adv_bearer_request_can_send_now_for_provisioning_pdu();
180                     break;
181                 default:
182                     break;
183             }
184             break;
185 #ifdef ENABLE_MESH_PROVISIONER
186         case MESH_GENERIC_PROVISIONING_LINK_ACK:   // Acknowledge a session on a bearer
187             if (link_state != LINK_STATE_W4_ACK) break;
188             link_state = LINK_STATE_OPEN;
189             pb_adv_msg_out_transaction_nr = 0;
190             pb_adv_msg_in_transaction_nr = 0x7f;    // first transaction nr will be 0x80
191             pb_adv_msg_in_transaction_nr_prev = 0x7f;
192             btstack_run_loop_remove_timer(&pb_adv_random_delay_timer);
193             log_info("link open, id %08x", pb_adv_link_id);
194             printf("PB-ADV: Link Open %08x\n", pb_adv_link_id);
195             pb_adv_emit_link_open(0, pb_adv_cid);
196             break;
197 #endif
198         case MESH_GENERIC_PROVISIONING_LINK_CLOSE: // Close a session on a bearer
199             // does it match link id
200             if (link_id != pb_adv_link_id) break;
201             reason = pdu[1];
202             link_state = LINK_STATE_W4_OPEN;
203             log_info("link close, reason %x", reason);
204             pb_adv_emit_link_close(pb_adv_cid, reason);
205             break;
206         default:
207             log_info("BearerOpcode %x reserved for future use\n", bearer_opcode);
208             break;
209     }
210 }
211 
212 static void pb_adv_pdu_complete(void){
213 
214     // Verify FCS
215     uint8_t pdu_crc = btstack_crc8_calc((uint8_t*)pb_adv_msg_in_buffer, pb_adv_msg_in_len);
216     if (pdu_crc != pb_adv_msg_in_fcs){
217         printf("Incoming PDU: fcs %02x, calculated %02x -> drop packet\n", pb_adv_msg_in_fcs, btstack_crc8_calc(pb_adv_msg_in_buffer, pb_adv_msg_in_len));
218         return;
219     }
220 
221     printf("PB-ADV: %02x complete\n", pb_adv_msg_in_transaction_nr);
222 
223     // transaction complete
224     pb_adv_msg_in_transaction_nr_prev = pb_adv_msg_in_transaction_nr;
225     if (pb_adv_provisioner_role){
226         pb_adv_msg_in_transaction_nr = 0x7f;    // invalid
227     } else {
228         pb_adv_msg_in_transaction_nr = 0xff;    // invalid
229     }
230 
231     // Ack Transaction
232     pb_adv_msg_in_send_ack = 1;
233     pb_adv_run();
234 
235     // Forward to Provisioning
236     pb_adv_packet_handler(PROVISIONING_DATA_PACKET, 0, pb_adv_msg_in_buffer, pb_adv_msg_in_len);
237 }
238 
239 static void pb_adv_handle_transaction_start(uint8_t transaction_nr, const uint8_t * pdu, uint16_t size){
240 
241     // resend ack if packet from previous transaction received
242     if (transaction_nr != 0xff && transaction_nr == pb_adv_msg_in_transaction_nr_prev){
243         printf("PB_ADV: %02x transaction complete, resending ack \n", transaction_nr);
244         pb_adv_msg_in_send_ack = 1;
245         return;
246     }
247 
248     // new transaction?
249     if (transaction_nr != pb_adv_msg_in_transaction_nr){
250 
251         // check len
252         uint16_t msg_len = big_endian_read_16(pdu, 1);
253         if (msg_len > MESH_PB_ADV_MAX_PDU_SIZE){
254             // abort transaction
255             return;
256         }
257 
258         // check num segments
259         uint8_t last_segment = pdu[0] >> 2;
260         if (last_segment >= MESH_PB_ADV_MAX_SEGMENTS){
261             // abort transaction
262             return;
263         }
264 
265         printf("PB-ADV: %02x started\n", transaction_nr);
266 
267         pb_adv_msg_in_transaction_nr = transaction_nr;
268         pb_adv_msg_in_len            = msg_len;
269         pb_adv_msg_in_fcs            = pdu[3];
270         pb_adv_msg_in_last_segment   = last_segment;
271 
272         // set bits for  segments 1..n (segment 0 already received in this message)
273         pb_adv_msg_in_segments_missing = (1 << last_segment) - 1;
274 
275         // store payload
276         uint16_t payload_len = size - 4;
277         memcpy(pb_adv_msg_in_buffer, &pdu[4], payload_len);
278 
279         // complete?
280         if (pb_adv_msg_in_segments_missing == 0){
281             pb_adv_pdu_complete();
282         }
283     }
284 }
285 
286 static void pb_adv_handle_transaction_cont(uint8_t transaction_nr, const uint8_t * pdu, uint16_t size){
287 
288     // check transaction nr
289     if (transaction_nr != 0xff && transaction_nr == pb_adv_msg_in_transaction_nr_prev){
290         printf("PB_ADV: %02x transaction complete, resending resending ack\n", transaction_nr);
291         pb_adv_msg_in_send_ack = 1;
292         return;
293     }
294 
295     if (transaction_nr != pb_adv_msg_in_transaction_nr){
296         printf("PB-ADV: %02x received msg for transaction nr %x\n", pb_adv_msg_in_transaction_nr, transaction_nr);
297         return;
298     }
299 
300     // validate seg nr
301     uint8_t seg = pdu[0] >> 2;
302     if (seg >= MESH_PB_ADV_MAX_SEGMENTS || seg == 0){
303         return;
304     }
305 
306     // check if segment already received
307     uint8_t seg_mask = 1 << (seg-1);
308     if ((pb_adv_msg_in_segments_missing & seg_mask) == 0){
309         printf("PB-ADV: %02x, segment %u already received\n", transaction_nr, seg);
310         return;
311     }
312     printf("PB-ADV: %02x, segment %u stored\n", transaction_nr, seg);
313 
314     // calculate offset and fragment size
315     uint16_t msg_pos = MESH_PB_ADV_START_PAYLOAD + (seg-1) * MESH_PB_ADV_CONT_PAYLOAD;
316     uint16_t fragment_size = size - 1;
317 
318     // check size if last segment
319     if (seg == pb_adv_msg_in_last_segment && (msg_pos + fragment_size) != pb_adv_msg_in_len){
320         // last segment has invalid size
321         return;
322     }
323 
324     // store segment and mark as received
325     memcpy(&pb_adv_msg_in_buffer[msg_pos], &pdu[1], fragment_size);
326     pb_adv_msg_in_segments_missing &= ~seg_mask;
327 
328      // last segment
329      if (pb_adv_msg_in_segments_missing == 0){
330         pb_adv_pdu_complete();
331     }
332 }
333 
334 static void pb_adv_outgoing_transation_complete(uint8_t status){
335     // stop sending
336     pb_adv_msg_out_active = 0;
337     // emit done
338     pb_adv_emit_pdu_sent(status);
339     // keep track of ack'ed transactions
340     pb_adv_msg_out_completed_transaction_nr = pb_adv_msg_out_transaction_nr;
341     // increment outgoing transaction nr
342     pb_adv_msg_out_transaction_nr++;
343     if (pb_adv_msg_out_transaction_nr == 0x00){
344         // Device role
345         pb_adv_msg_out_transaction_nr = 0x80;
346     }
347     if (pb_adv_msg_out_transaction_nr == 0x80){
348         // Provisioner role
349         pb_adv_msg_out_transaction_nr = 0x00;
350     }
351 }
352 
353 static void pb_adv_handle_transaction_ack(uint8_t transaction_nr, const uint8_t * pdu, uint16_t size){
354     if (transaction_nr == pb_adv_msg_out_transaction_nr){
355         printf("PB-ADV: %02x ACK received\n", transaction_nr);
356         pb_adv_outgoing_transation_complete(ERROR_CODE_SUCCESS);
357     } else if (transaction_nr == pb_adv_msg_out_completed_transaction_nr){
358         // Transaction ack received again
359     } else {
360         printf("PB-ADV: %02x unexpected Transaction ACK %x recevied\n", pb_adv_msg_out_transaction_nr, transaction_nr);
361     }
362 }
363 
364 static int pb_adv_packet_to_send(void){
365     return pb_adv_msg_in_send_ack || pb_adv_msg_out_active || (link_state == LINK_STATE_W4_ACK);
366 }
367 
368 static void pb_adv_timer_handler(btstack_timer_source_t * ts){
369     pb_adv_random_delay_active = 0;
370     if (!pb_adv_packet_to_send()) return;
371     adv_bearer_request_can_send_now_for_provisioning_pdu();
372 }
373 
374 static void pb_adv_run(void){
375     if (!pb_adv_packet_to_send()) return;
376     if (pb_adv_random_delay_active) return;
377 
378     // spec recommends 20-50 ms, we use 20-51 ms
379     pb_adv_random_delay_active = 1;
380     uint16_t random_delay_ms = 20 + (pb_adv_random() & 0x1f);
381     log_info("random delay %u ms", random_delay_ms);
382     btstack_run_loop_set_timer_handler(&pb_adv_random_delay_timer, &pb_adv_timer_handler);
383     btstack_run_loop_set_timer(&pb_adv_random_delay_timer, random_delay_ms);
384     btstack_run_loop_add_timer(&pb_adv_random_delay_timer);
385 }
386 
387 static void pb_adv_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
388     if (packet_type != HCI_EVENT_PACKET) return;
389     const uint8_t * data;
390     uint8_t  length;
391     uint32_t link_id;
392     uint8_t  transaction_nr;
393     uint8_t  generic_provisioning_control;
394     switch(packet[0]){
395         case GAP_EVENT_ADVERTISING_REPORT:
396 
397             data = gap_event_advertising_report_get_data(packet);
398             // PDB ADV PDU
399             length = data[0];
400             link_id = big_endian_read_32(data, 2);
401             transaction_nr = data[6];
402             // generic provision PDU
403             generic_provisioning_control = data[7];
404             mesh_gpcf_format_t generic_provisioning_control_format = (mesh_gpcf_format_t) generic_provisioning_control & 3;
405 
406             // unless, we're waiting for LINK_OPEN, check link_id
407             if (link_state != LINK_STATE_W4_OPEN){
408                 if (link_id != pb_adv_link_id) break;
409             }
410 
411             if (generic_provisioning_control_format == MESH_GPCF_PROV_BEARER_CONTROL){
412                 pb_adv_handle_bearer_control(link_id, transaction_nr, &data[7], length-6);
413                 break;
414             }
415 
416             // verify link id and link state
417             if (link_state != LINK_STATE_OPEN) break;
418 
419             switch (generic_provisioning_control_format){
420                 case MESH_GPCF_TRANSACTION_START:
421                     pb_adv_handle_transaction_start(transaction_nr, &data[7], length-6);
422                     break;
423                 case MESH_GPCF_TRANSACTION_CONT:
424                     pb_adv_handle_transaction_cont(transaction_nr, &data[7], length-6);
425                     break;
426                 case MESH_GPCF_TRANSACTION_ACK:
427                     pb_adv_handle_transaction_ack(transaction_nr, &data[7], length-6);
428                     break;
429                 default:
430                     break;
431             }
432             pb_adv_run();
433             break;
434         case HCI_EVENT_MESH_META:
435             switch(packet[2]){
436                 case MESH_SUBEVENT_CAN_SEND_NOW:
437                     if (link_state == LINK_STATE_W4_ACK){
438                         // build packet
439                         uint8_t buffer[22];
440                         big_endian_store_32(buffer, 0, pb_adv_link_id);
441                         buffer[4] = 0;            // Transaction ID = 0
442                         buffer[5] = (0 << 2) | 3; // Link Open | Provisioning Bearer Control
443                         memcpy(&buffer[6], pb_adv_peer_device_uuid, 16);
444                         adv_bearer_send_provisioning_pdu(buffer, sizeof(buffer));
445                         log_info("link open %08x", pb_adv_link_id);
446                         printf("PB-ADV: Sending Link Open for device uuid: ");
447                         printf_hexdump(pb_adv_peer_device_uuid, 16);
448                         btstack_run_loop_set_timer_handler(&pb_adv_random_delay_timer, &pb_adv_timer_handler);
449                         btstack_run_loop_set_timer(&pb_adv_random_delay_timer, PB_ADV_LINK_OPEN_RETRANSMIT_MS);
450                         btstack_run_loop_add_timer(&pb_adv_random_delay_timer);
451                         break;
452                     }
453                     if (link_state == LINK_STATE_CLOSING){
454                         log_info("link close %08x", pb_adv_link_id);
455                         printf("PB-ADV: Sending Link Close\n");
456                         // build packet
457                         uint8_t buffer[7];
458                         big_endian_store_32(buffer, 0, pb_adv_link_id);
459                         buffer[4] = 0;            // Transaction ID = 0
460                         buffer[5] = (2 << 2) | 3; // Link Close | Provisioning Bearer Control
461                         buffer[6] = pb_adv_link_close_reason;
462                         adv_bearer_send_provisioning_pdu(buffer, sizeof(buffer));
463                         pb_adv_link_close_countdown--;
464                         if (pb_adv_link_close_countdown) {
465                             adv_bearer_request_can_send_now_for_provisioning_pdu();
466                         } else {
467                             link_state = LINK_STATE_W4_OPEN;
468                         }
469                         break;
470                     }
471                     if (link_state == LINK_STATE_W2_SEND_ACK){
472                         link_state = LINK_STATE_OPEN;
473                         pb_adv_msg_out_transaction_nr = 0x80;
474                         // build packet
475                         uint8_t buffer[6];
476                         big_endian_store_32(buffer, 0, pb_adv_link_id);
477                         buffer[4] = 0;
478                         buffer[5] = (1 << 2) | 3; // Link Ack | Provisioning Bearer Control
479                         adv_bearer_send_provisioning_pdu(buffer, sizeof(buffer));
480                         log_info("link ack %08x", pb_adv_link_id);
481                         printf("PB-ADV: Sending Link Open Ack\n");
482                         break;
483                     }
484                     if (pb_adv_msg_in_send_ack){
485                         pb_adv_msg_in_send_ack = 0;
486                         uint8_t buffer[6];
487                         big_endian_store_32(buffer, 0, pb_adv_link_id);
488                         buffer[4] = pb_adv_msg_in_transaction_nr_prev;
489                         buffer[5] = MESH_GPCF_TRANSACTION_ACK;
490                         adv_bearer_send_provisioning_pdu(buffer, sizeof(buffer));
491                         log_info("transaction ack %08x", pb_adv_link_id);
492                         printf("PB-ADV: %02x sending ACK\n", pb_adv_msg_in_transaction_nr_prev);
493                         pb_adv_run();
494                         break;
495                     }
496                     if (pb_adv_msg_out_active){
497 
498                         // check timeout for outgoing message
499                         // since uint32_t is used and time now must be greater than pb_adv_msg_out_start,
500                         // this claculation is correct even when the run loop time overruns
501                         uint32_t transaction_time_ms = btstack_run_loop_get_time_ms() - pb_adv_msg_out_start;
502                         if (transaction_time_ms >= MESH_GENERIC_PROVISIONING_TRANSACTION_TIMEOUT_MS){
503                             pb_adv_outgoing_transation_complete(ERROR_CODE_CONNECTION_TIMEOUT);
504                             return;
505                         }
506 
507                         uint8_t buffer[29]; // ADV MTU
508                         big_endian_store_32(buffer, 0, pb_adv_link_id);
509                         buffer[4] = pb_adv_msg_out_transaction_nr;
510                         uint16_t bytes_left;
511                         uint16_t pos;
512                         if (pb_adv_msg_out_pos == 0){
513                             // Transaction start
514                             int seg_n = pb_adv_msg_out_len / 24;
515                             pb_adv_msg_out_seg = 0;
516                             buffer[5] = seg_n << 2 | MESH_GPCF_TRANSACTION_START;
517                             big_endian_store_16(buffer, 6, pb_adv_msg_out_len);
518                             buffer[8] = btstack_crc8_calc((uint8_t*)pb_adv_msg_out_buffer, pb_adv_msg_out_len);
519                             pos = 9;
520                             bytes_left = 24 - 4;
521                             printf("PB-ADV: %02x Sending Start: ", pb_adv_msg_out_transaction_nr);
522                         } else {
523                             // Transaction continue
524                             buffer[5] = pb_adv_msg_out_seg << 2 | MESH_GPCF_TRANSACTION_CONT;
525                             pos = 6;
526                             bytes_left = 24 - 1;
527                             printf("PB-ADV: %02x Sending Cont:  ", pb_adv_msg_out_transaction_nr);
528                         }
529                         pb_adv_msg_out_seg++;
530                         uint16_t bytes_to_copy = btstack_min(bytes_left, pb_adv_msg_out_len - pb_adv_msg_out_pos);
531                         memcpy(&buffer[pos], &pb_adv_msg_out_buffer[pb_adv_msg_out_pos], bytes_to_copy);
532                         pos += bytes_to_copy;
533                         printf("bytes %02u, pos %02u, len %02u: ", bytes_to_copy, pb_adv_msg_out_pos, pb_adv_msg_out_len);
534                         printf_hexdump(buffer, pos);
535                         pb_adv_msg_out_pos += bytes_to_copy;
536 
537                         if (pb_adv_msg_out_pos == pb_adv_msg_out_len){
538                             // done
539                             pb_adv_msg_out_pos = 0;
540                         }
541                         adv_bearer_send_provisioning_pdu(buffer, pos);
542                         pb_adv_run();
543                         break;
544                     }
545                     break;
546                 default:
547                     break;
548             }
549         default:
550             break;
551     }
552 }
553 
554 void pb_adv_init(void){
555     adv_bearer_register_for_provisioning_pdu(&pb_adv_handler);
556     pb_adv_lfsr = 0x12345678;
557     pb_adv_random();
558 }
559 
560 void pb_adv_register_packet_handler(btstack_packet_handler_t packet_handler){
561     pb_adv_packet_handler = packet_handler;
562 }
563 
564 void pb_adv_send_pdu(uint16_t pb_adv_cid, const uint8_t * pdu, uint16_t size){
565     UNUSED(pb_adv_cid);
566     printf("PB-ADV: Send packet ");
567     printf_hexdump(pdu, size);
568     pb_adv_msg_out_buffer = pdu;
569     pb_adv_msg_out_len    = size;
570     pb_adv_msg_out_pos = 0;
571     pb_adv_msg_out_start = btstack_run_loop_get_time_ms();
572     pb_adv_msg_out_active = 1;
573     pb_adv_run();
574 }
575 
576 /**
577  * Close Link
578  * @param pb_adv_cid
579  */
580 void pb_adv_close_link(uint16_t pb_adv_cid, uint8_t reason){
581     switch (link_state){
582         case LINK_STATE_W4_ACK:
583         case LINK_STATE_OPEN:
584         case LINK_STATE_W2_SEND_ACK:
585             pb_adv_emit_link_close(pb_adv_cid, 0);
586             link_state = LINK_STATE_CLOSING;
587             pb_adv_link_close_countdown = 3;
588             pb_adv_link_close_reason = reason;
589             adv_bearer_request_can_send_now_for_provisioning_pdu();
590             break;
591         case LINK_STATE_W4_OPEN:
592         case LINK_STATE_CLOSING:
593             // nothing to do
594             break;
595     }
596 }
597 
598 #ifdef ENABLE_MESH_PROVISIONER
599 uint16_t pb_adv_create_link(const uint8_t * device_uuid){
600     if (link_state != LINK_STATE_W4_OPEN) return 0;
601 
602     pb_adv_peer_device_uuid = device_uuid;
603     pb_adv_provisioner_role = 1;
604 
605     // create new 32-bit link id
606     pb_adv_link_id = pb_adv_random();
607 
608     // after sending OPEN, we wait for an ACK
609     link_state = LINK_STATE_W4_ACK;
610 
611     // request outgoing
612     adv_bearer_request_can_send_now_for_provisioning_pdu();
613 
614     // dummy pb_adv_cid
615     return pb_adv_cid;
616 }
617 #endif
618 
619