xref: /btstack/example/panu_demo.c (revision 360243be41f47158adff357b9fead2686419a2df)
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__ "panu_demo.c"
39 
40 /*
41  * panu_demo.c
42  * Author: Ole Reinhardt <[email protected]>
43  */
44 
45 /* EXAMPLE_START(panu_demo): PANU Demo
46  *
47  * @text This example implements both a PANU client and a server. In server mode, it
48  * sets up a BNEP server and registers a PANU SDP record and waits for incoming connections.
49  * In client mode, it connects to a remote device, does an SDP Query to identify the PANU
50  * service and initiates a BNEP connection.
51  */
52 
53 #include "btstack_config.h"
54 
55 #include <arpa/inet.h>
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <ifaddrs.h>
59 #include <stdint.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <unistd.h>
64 
65 #include <net/if_arp.h>
66 
67 #ifdef __APPLE__
68 #include <net/if.h>
69 #include <net/if_types.h>
70 
71 #include <netinet/if_ether.h>
72 #include <netinet/in.h>
73 #endif
74 
75 #include <sys/ioctl.h>
76 #include <sys/param.h>
77 #include <sys/socket.h>
78 #include <sys/stat.h>
79 #include <sys/types.h>
80 
81 #ifdef __linux
82 #include <linux/if.h>
83 #include <linux/if_tun.h>
84 #endif
85 
86 #include "btstack.h"
87 
88 static int record_id = -1;
89 static uint16_t bnep_l2cap_psm      = 0;
90 static uint32_t bnep_remote_uuid    = 0;
91 static uint16_t bnep_version        = 0;
92 static uint16_t bnep_cid            = 0;
93 
94 static uint16_t sdp_bnep_l2cap_psm      = 0;
95 static uint16_t sdp_bnep_version        = 0;
96 static uint32_t sdp_bnep_remote_uuid    = 0;
97 
98 static uint8_t   attribute_value[1000];
99 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
100 
101 // MBP 2016 static const char * remote_addr_string = "F4-0F-24-3B-1B-E1";
102 // Wiko Sunny
103 static const char * remote_addr_string = "A0:4C:5B:0F:B2:42";
104 static bd_addr_t remote_addr;
105 
106 static int  tap_fd = -1;
107 static uint8_t network_buffer[BNEP_MTU_MIN];
108 static size_t  network_buffer_len = 0;
109 
110 #ifdef __APPLE__
111 // tuntaposx provides fixed set of tapX devices
112 static const char * tap_dev = "/dev/tap0";
113 static char tap_dev_name[16] = "tap0";
114 #endif
115 
116 #ifdef __linux
117 // Linux uses single control device to bring up tunX or tapX interface
118 static const char * tap_dev = "/dev/net/tun";
119 static char tap_dev_name[16] = "bnep%d";
120 #endif
121 
122 
123 static btstack_data_source_t tap_dev_ds;
124 static btstack_packet_callback_registration_t hci_event_callback_registration;
125 
126 /* @section Main application configuration
127  *
128  * @text In the application configuration, L2CAP and BNEP are initialized and a BNEP service, for server mode,
129  * is registered, before the Bluetooth stack gets started, as shown in Listing PanuSetup.
130  */
131 
132 /* LISTING_START(PanuSetup): Panu setup */
133 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
134 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
135 
136 static void panu_setup(void){
137 
138     // register for HCI events
139     hci_event_callback_registration.callback = &packet_handler;
140     hci_add_event_handler(&hci_event_callback_registration);
141 
142     // Initialize L2CAP
143     l2cap_init();
144 
145     // Initialise BNEP
146     bnep_init();
147     // Minimum L2CAP MTU for bnep is 1691 bytes
148     bnep_register_service(packet_handler, BLUETOOTH_SERVICE_CLASS_PANU, 1691);
149 }
150 /* LISTING_END */
151 
152 /* @section TUN / TAP interface routines
153  *
154  * @text This example requires a TUN/TAP interface to connect the Bluetooth network interface
155  * with the native system. It has been tested on Linux and OS X, but should work on any
156  * system that provides TUN/TAP with minor modifications.
157  *
158  * On Linux, TUN/TAP is available by default. On OS X, tuntaposx from
159  * http://tuntaposx.sourceforge.net needs to be installed.
160  *
161  * The *tap_alloc* function sets up a virtual network interface with the given Bluetooth Address.
162  * It is rather low-level as it sets up and configures a network interface.
163  */
164 
165 static int tap_alloc(char *dev, bd_addr_t bd_addr)
166 {
167     struct ifreq ifr;
168     int fd_dev;
169     int fd_socket;
170 
171     if( (fd_dev = open(tap_dev, O_RDWR)) < 0 ) {
172         fprintf(stderr, "TAP: Error opening %s: %s\n", tap_dev, strerror(errno));
173         return -1;
174     }
175 
176 #ifdef __linux
177     memset(&ifr, 0, sizeof(ifr));
178 
179     ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
180     if( *dev ) {
181         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
182     }
183 
184     int err;
185     if( (err = ioctl(fd_dev, TUNSETIFF, (void *) &ifr)) < 0 ) {
186         fprintf(stderr, "TAP: Error setting device name: %s\n", strerror(errno));
187         close(fd_dev);
188         return -1;
189     }
190     strcpy(dev, ifr.ifr_name);
191 #endif
192 #ifdef __APPLE__
193     dev = tap_dev_name;
194 #endif
195 
196     fd_socket = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
197 	if (fd_socket < 0) {
198         close(fd_dev);
199 		fprintf(stderr, "TAP: Error opening netlink socket: %s\n", strerror(errno));
200 		return -1;
201 	}
202 
203     // Configure the MAC address of the newly created bnep(x)
204     // device to the local bd_address
205     memset (&ifr, 0, sizeof(struct ifreq));
206     strcpy(ifr.ifr_name, dev);
207 #ifdef __linux
208     ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
209     memcpy(ifr.ifr_hwaddr.sa_data, bd_addr, sizeof(bd_addr_t));
210 	if (ioctl(fd_socket, SIOCSIFHWADDR, &ifr) == -1) {
211         close(fd_dev);
212         close(fd_socket);
213         fprintf(stderr, "TAP: Error setting hw addr: %s\n", strerror(errno));
214         exit(1);
215 		return -1;
216 	}
217 #endif
218 #ifdef __APPLE__
219     ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
220     ifr.ifr_addr.sa_family = AF_LINK;
221     (void)memcpy(ifr.ifr_addr.sa_data, bd_addr, ETHER_ADDR_LEN);
222     if (ioctl(fd_socket, SIOCSIFLLADDR, &ifr) == -1) {
223         close(fd_dev);
224         close(fd_socket);
225         fprintf(stderr, "TAP: Error setting hw addr: %s\n", strerror(errno));
226         exit(1);
227         return -1;
228 }
229 #endif
230 
231     // Bring the interface up
232 	if (ioctl(fd_socket, SIOCGIFFLAGS, &ifr) == -1) {
233         close(fd_dev);
234         close(fd_socket);
235 		fprintf(stderr, "TAP: Error reading interface flags: %s\n", strerror(errno));
236 		return -1;
237 	}
238 
239 	if ((ifr.ifr_flags & IFF_UP) == 0) {
240 		ifr.ifr_flags |= IFF_UP;
241 
242 		if (ioctl(fd_socket, SIOCSIFFLAGS, &ifr) == -1) {
243             close(fd_dev);
244             close(fd_socket);
245             fprintf(stderr, "TAP: Error set IFF_UP: %s\n", strerror(errno));
246             return -1;
247 		}
248 	}
249 
250 	close(fd_socket);
251 
252     return fd_dev;
253 }
254 
255 /*
256  * @text Listing processTapData shows how a packet is received from the TAP network interface
257  * and forwarded over the BNEP connection.
258  *
259  * After successfully reading a network packet, the call to
260  * the *bnep_can_send_packet_now* function checks, if BTstack can forward
261  * a network packet now. If that's not possible, the received data stays
262  * in the network buffer and the data source elements is removed from the
263  * run loop. The *process_tap_dev_data* function will not be called until
264  * the data source is registered again. This provides a basic flow control.
265  */
266 
267 /* LISTING_START(processTapData): Process incoming network packets */
268 static void process_tap_dev_data(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type)
269 {
270     UNUSED(ds);
271     UNUSED(callback_type);
272 
273     ssize_t len;
274     len = read(ds->fd, network_buffer, sizeof(network_buffer));
275     if (len <= 0){
276         fprintf(stderr, "TAP: Error while reading: %s\n", strerror(errno));
277         return;
278     }
279 
280     network_buffer_len = len;
281 
282     // disable reading from netif
283     btstack_run_loop_disable_data_source_callbacks(&tap_dev_ds, DATA_SOURCE_CALLBACK_READ);
284 
285     // request permission to send
286     bnep_request_can_send_now_event(bnep_cid);
287 }
288 /* LISTING_END */
289 
290 // PANU client routines
291 static char * get_string_from_data_element(uint8_t * element){
292     de_size_t de_size = de_get_size_type(element);
293     int pos     = de_get_header_size(element);
294     int len = 0;
295     switch (de_size){
296         case DE_SIZE_VAR_8:
297             len = element[1];
298             break;
299         case DE_SIZE_VAR_16:
300             len = big_endian_read_16(element, 1);
301             break;
302         default:
303             break;
304     }
305     char * str = (char*)malloc(len+1);
306     memcpy(str, &element[pos], len);
307     str[len] ='\0';
308     return str;
309 }
310 
311 
312 /* @section SDP parser callback
313  *
314  * @text The SDP parsers retrieves the BNEP PAN UUID as explained in
315  * Section [on SDP BNEP Query example](#sec:sdpbnepqueryExample}.
316  */
317 static void handle_sdp_client_record_complete(void){
318 
319     printf("SDP BNEP Record complete\n");
320 
321     // accept first entry or if we foudn a NAP and only have a PANU yet
322     if ((bnep_remote_uuid == 0) || (sdp_bnep_remote_uuid == BLUETOOTH_SERVICE_CLASS_NAP && bnep_remote_uuid == BLUETOOTH_SERVICE_CLASS_PANU)){
323         bnep_l2cap_psm   = sdp_bnep_l2cap_psm;
324         bnep_remote_uuid = sdp_bnep_remote_uuid;
325         bnep_version     = sdp_bnep_version;
326     }
327 }
328 
329 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {
330 
331     UNUSED(packet_type);
332     UNUSED(channel);
333     UNUSED(size);
334 
335     des_iterator_t des_list_it;
336     des_iterator_t prot_it;
337     char *str;
338 
339     switch (hci_event_packet_get_type(packet)){
340         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
341             // Handle new SDP record
342             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
343                 handle_sdp_client_record_complete();
344                 // next record started
345                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
346                 printf("SDP Record: Nr: %d\n", record_id);
347             }
348 
349             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
350                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
351 
352                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
353 
354                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
355                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
356                             if (de_get_element_type(attribute_value) != DE_DES) break;
357                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
358                                 uint8_t * element = des_iterator_get_element(&des_list_it);
359                                 if (de_get_element_type(element) != DE_UUID) continue;
360                                 uint32_t uuid = de_get_uuid32(element);
361                                 switch (uuid){
362                                     case BLUETOOTH_SERVICE_CLASS_PANU:
363                                     case BLUETOOTH_SERVICE_CLASS_NAP:
364                                     case BLUETOOTH_SERVICE_CLASS_GN:
365                                         printf("SDP Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
366                                         sdp_bnep_remote_uuid = uuid;
367                                         break;
368                                     default:
369                                         break;
370                                 }
371                             }
372                             break;
373                         case 0x0100:
374                         case 0x0101:
375                             str = get_string_from_data_element(attribute_value);
376                             printf("SDP Attribute: 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
377                             free(str);
378                             break;
379                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
380                                 printf("SDP Attribute: 0x%04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet));
381 
382                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
383                                     uint8_t       *des_element;
384                                     uint8_t       *element;
385                                     uint32_t       uuid;
386 
387                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
388 
389                                     des_element = des_iterator_get_element(&des_list_it);
390                                     des_iterator_init(&prot_it, des_element);
391                                     element = des_iterator_get_element(&prot_it);
392 
393                                     if (de_get_element_type(element) != DE_UUID) continue;
394 
395                                     uuid = de_get_uuid32(element);
396                                     switch (uuid){
397                                         case BLUETOOTH_PROTOCOL_L2CAP:
398                                             if (!des_iterator_has_more(&prot_it)) continue;
399                                             des_iterator_next(&prot_it);
400                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_bnep_l2cap_psm);
401                                             break;
402                                         case BLUETOOTH_PROTOCOL_BNEP:
403                                             if (!des_iterator_has_more(&prot_it)) continue;
404                                             des_iterator_next(&prot_it);
405                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_bnep_version);
406                                             break;
407                                         default:
408                                             break;
409                                     }
410                                 }
411                                 printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", bnep_l2cap_psm, bnep_version);
412 
413                             }
414                             break;
415                         default:
416                             break;
417                     }
418                 }
419             } else {
420                 fprintf(stderr, "SDP attribute value buffer size exceeded: available %d, required %d\n", attribute_value_buffer_size, sdp_event_query_attribute_byte_get_attribute_length(packet));
421             }
422             break;
423 
424         case SDP_EVENT_QUERY_COMPLETE:
425             handle_sdp_client_record_complete();
426             fprintf(stderr, "General query done with status %d, bnep psm %04x.\n", sdp_event_query_complete_get_status(packet), bnep_l2cap_psm);
427             if (bnep_l2cap_psm){
428                 /* Create BNEP connection */
429                 bnep_connect(packet_handler, remote_addr, bnep_l2cap_psm, BLUETOOTH_SERVICE_CLASS_PANU, bnep_remote_uuid);
430             } else {
431                 fprintf(stderr, "No BNEP service found\n");
432             }
433 
434             break;
435     }
436 }
437 
438 /*
439  * @section Packet Handler
440  *
441  * @text The packet handler responds to various HCI Events.
442  */
443 
444 
445 /* LISTING_START(packetHandler): Packet Handler */
446 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)
447 {
448 /* LISTING_PAUSE */
449     UNUSED(channel);
450 
451     int       rc;
452     uint8_t   event;
453     bd_addr_t event_addr;
454     bd_addr_t local_addr;
455     uint16_t  uuid_source;
456     uint16_t  uuid_dest;
457     uint16_t  mtu;
458 
459     /* LISTING_RESUME */
460     switch (packet_type) {
461 		case HCI_EVENT_PACKET:
462             event = hci_event_packet_get_type(packet);
463             switch (event) {
464                 /* @text When BTSTACK_EVENT_STATE with state HCI_STATE_WORKING
465                  * is received and the example is started in client mode, the remote SDP BNEP query is started.
466                  */
467                 case BTSTACK_EVENT_STATE:
468                     if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){
469                         printf("Start SDP BNEP query.\n");
470                         sdp_client_query_uuid16(&handle_sdp_client_query_result, remote_addr, BLUETOOTH_PROTOCOL_BNEP);
471                     }
472                     break;
473 
474                 /* LISTING_PAUSE */
475                 case HCI_EVENT_PIN_CODE_REQUEST:
476 					// inform about pin code request
477                     printf("Pin code request - using '0000'\n");
478                     hci_event_pin_code_request_get_bd_addr(packet, event_addr);
479                     gap_pin_code_response(event_addr, "0000");
480 					break;
481 
482                 case HCI_EVENT_USER_CONFIRMATION_REQUEST:
483                     // inform about user confirmation request
484                     printf("SSP User Confirmation Request with numeric value '%06u'\n", little_endian_read_32(packet, 8));
485                     printf("SSP User Confirmation Auto accept\n");
486                     break;
487 
488                 /* LISTING_RESUME */
489 
490                 /* @text BNEP_EVENT_CHANNEL_OPENED is received after a BNEP connection was established or
491                  * or when the connection fails. The status field returns the error code.
492                  *
493                  * The TAP network interface is then configured. A data source is set up and registered with the
494                  * run loop to receive Ethernet packets from the TAP interface.
495                  *
496                  * The event contains both the source and destination UUIDs, as well as the MTU for this connection and
497                  * the BNEP Channel ID, which is used for sending Ethernet packets over BNEP.
498                  */
499 				case BNEP_EVENT_CHANNEL_OPENED:
500                     if (bnep_event_channel_opened_get_status(packet)) {
501                         printf("BNEP channel open failed, status %02x\n", bnep_event_channel_opened_get_status(packet));
502                     } else {
503                         bnep_cid    = bnep_event_channel_opened_get_bnep_cid(packet);
504                         uuid_source = bnep_event_channel_opened_get_source_uuid(packet);
505                         uuid_dest   = bnep_event_channel_opened_get_destination_uuid(packet);
506                         mtu         = bnep_event_channel_opened_get_mtu(packet);
507                         //bt_flip_addr(event_addr, &packet[9]);
508                         memcpy(&event_addr, &packet[11], sizeof(bd_addr_t));
509                         printf("BNEP connection open succeeded to %s source UUID 0x%04x dest UUID: 0x%04x, max frame size %u\n", bd_addr_to_str(event_addr), uuid_source, uuid_dest, mtu);
510                         /* Create the tap interface */
511                         gap_local_bd_addr(local_addr);
512                         tap_fd = tap_alloc(tap_dev_name, local_addr);
513                         if (tap_fd < 0) {
514                             printf("Creating BNEP tap device failed: %s\n", strerror(errno));
515                         } else {
516                             printf("BNEP device \"%s\" allocated.\n", tap_dev_name);
517                             /* Create and register a new runloop data source */
518                             btstack_run_loop_set_data_source_fd(&tap_dev_ds, tap_fd);
519                             btstack_run_loop_set_data_source_handler(&tap_dev_ds, &process_tap_dev_data);
520                             btstack_run_loop_add_data_source(&tap_dev_ds);
521                             btstack_run_loop_enable_data_source_callbacks(&tap_dev_ds, DATA_SOURCE_CALLBACK_READ);
522                         }
523                     }
524 					break;
525 
526                 /* @text If there is a timeout during the connection setup, BNEP_EVENT_CHANNEL_TIMEOUT will be received
527                  * and the BNEP connection  will be closed
528                  */
529                 case BNEP_EVENT_CHANNEL_TIMEOUT:
530                     printf("BNEP channel timeout! Channel will be closed\n");
531                     break;
532 
533                 /* @text BNEP_EVENT_CHANNEL_CLOSED is received when the connection gets closed.
534                  */
535                 case BNEP_EVENT_CHANNEL_CLOSED:
536                     printf("BNEP channel closed\n");
537                     btstack_run_loop_remove_data_source(&tap_dev_ds);
538                     if (tap_fd > 0) {
539                         close(tap_fd);
540                         tap_fd = -1;
541                     }
542                     break;
543 
544                 /* @text BNEP_EVENT_CAN_SEND_NOW indicates that a new packet can be send. This triggers the send of a
545                  * stored network packet. The tap datas source can be enabled again
546                  */
547                 case BNEP_EVENT_CAN_SEND_NOW:
548                     if (network_buffer_len > 0) {
549                         bnep_send(bnep_cid, network_buffer, network_buffer_len);
550                         network_buffer_len = 0;
551                         // Re-enable the tap device data source
552                         btstack_run_loop_enable_data_source_callbacks(&tap_dev_ds, DATA_SOURCE_CALLBACK_READ);
553                     }
554                     break;
555 
556                 default:
557                     break;
558             }
559             break;
560 
561         /* @text Ethernet packets from the remote device are received in the packet handler with type BNEP_DATA_PACKET.
562          * It is forwarded to the TAP interface.
563          */
564         case BNEP_DATA_PACKET:
565             // Write out the ethernet frame to the tap device
566             if (tap_fd > 0) {
567                 rc = write(tap_fd, packet, size);
568                 if (rc < 0) {
569                     fprintf(stderr, "TAP: Could not write to TAP device: %s\n", strerror(errno));
570                 } else
571                 if (rc != size) {
572                     fprintf(stderr, "TAP: Package written only partially %d of %d bytes\n", rc, size);
573                 }
574             }
575             break;
576 
577         default:
578             break;
579     }
580 }
581 /* LISTING_END */
582 
583 
584 int btstack_main(int argc, const char * argv[]);
585 int btstack_main(int argc, const char * argv[]){
586 
587     (void)argc;
588     (void)argv;
589 
590     panu_setup();
591 
592     // parse human readable Bluetooth address
593     sscanf_bd_addr(remote_addr_string, remote_addr);
594 
595     // Turn on the device
596     hci_power_control(HCI_POWER_ON);
597     return 0;
598 }
599 
600 /* EXAMPLE_END */
601 /* -*- Mode: C; indent-tabs-mode: nil; c-basic-offset: 4; tab-width: 4 -*-  */
602 
603