Attempting to print out device name data with "device_found()" in "central_hrs"

Question

Hi, 
 I am trying to modify the Zephyr central_hrs module so that it will print out the name of any peripheral it discovers and eventually store them in some 2D array. The problem is that I can't get it to work properly. I found this post: How to read advertising BLE devices' name? which does let you print out device names. The issue is that they are using the generic "central" example and bt_data_parse() eats the pointer to the advertisement data you give it so it can't be reused. In "central_hr" you already have an essential call to bt_data_parse() in order to establish a connection. The obvious solution to this is to create "struct net_buf_simple ad_temp" and copy the advertisement data structure into it but all attempts to do so have failed. Everything I have tried has either given me a memory fault or or just given me garbled characters. I also tried modifying the existing bt_data_parse() callback function in "central_hr" but to little success. I don't know if this is more a zephyr or a straight up C fundamentals question but any help copying the advertisement data into a temporary net_buf_simple struct would be greatly appreciated. I will post the relevant code I have below: 
 This is the central_code. In this state it the code seems to memory fault and I am not sure why: 
 
 static bool eir_found ( struct bt_data * data , void * user_data ) 
 { 
 bt_addr_le_t * addr = user_data ; 
 int i ; 
 
 printk ( "[AD]: %u data_len %u Actual Data: %u 
 " , data -> type , data -> data_len , data -> data ); 
 
 switch ( data -> type ) { 
 case BT_DATA_UUID16_SOME : 
 case BT_DATA_UUID16_ALL : 
 if ( data -> data_len % sizeof ( uint16_t ) != 0U ) { 
 printk ( "AD malformed 
 " ); 
 return true ; 
 } 
 
 for ( i = 0 ; i < data -> data_len ; i += sizeof ( uint16_t )) { 
 struct bt_le_conn_param * param ; 
 struct bt_uuid * uuid ; 
 uint16_t u16 ; 
 int err ; 
 
 memcpy ( & u16 , & data -> data [ i ], sizeof ( u16 )); 
 
 uuid = BT_UUID_DECLARE_16 ( sys_le16_to_cpu ( u16 )); 
 if ( bt_uuid_cmp ( uuid , BT_UUID_HRS )) { 
 continue ; 
 } 
 
 err = bt_le_scan_stop (); 
 if ( err ) { 
 printk ( "Stop LE scan failed (err %d ) 
 " , err ); 
 continue ; 
 } 
 
 param = BT_LE_CONN_PARAM_DEFAULT ; 
 err = bt_conn_le_create ( addr , BT_CONN_LE_CREATE_CONN , 
 param , & default_conn ); 
 if ( err ) { 
 printk ( "Create conn failed (err %d ) 
 " , err ); 
 start_scan (); 
 } 
 
 return false ; 
 } 
 } 
 
 return true ; 
 } 
 
 static bool data_cb2 ( struct bt_data * data , void * user_data ){ 
 
 char * name = user_data ; 
 
 switch ( data -> type ){ 
 case BT_DATA_NAME_SHORTENED : 
 case BT_DATA_NAME_COMPLETE : 
 memcpy ( name , data -> data , MIN ( data -> data_len , NAME_LEN - 1 )); 
 return false ; 
 default : 
 return false ; 
 } 
 } 
 
 static void device_found ( const bt_addr_le_t * addr , int8_t rssi , uint8_t type , 
 struct net_buf_simple * ad ) 
 { 
 char dev [ BT_ADDR_LE_STR_LEN ]; 
 char name [ 30 ]; 
 struct net_buf_simple ad_temp ; 
 
 memcpy ( & ad_temp , ad -> data , net_buf_simple_max_len ( ad -> len )); 
 
 bt_addr_le_to_str ( & addr , dev , sizeof ( dev )); 
 
 bt_data_parse ( & ad_temp , data_cb2 , name ); 
 printk ( "Device found: %s 
 " , * name ); 
 
 printk ( "[DEVICE]: %s , AD evt type %u , AD data len %u , RSSI %i 
 " , 
 dev , type , ad -> len , rssi ); 
 
 /* We're only interested in connectable events */ 
 if ( type == BT_GAP_ADV_TYPE_ADV_IND || 
 type == BT_GAP_ADV_TYPE_ADV_DIRECT_IND ) { 
 bt_data_parse ( ad , eir_found , ( void * ) addr ); 
 } 
 } 
 
 And then here is the relevant stuff on the peripheral code: 
 
 static const struct bt_data ad [] = { 
 BT_DATA_BYTES ( BT_DATA_FLAGS , ( BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR )), 
 BT_DATA_BYTES ( BT_DATA_UUID16_ALL , 
 BT_UUID_16_ENCODE ( BT_UUID_HRS_VAL ), 
 BT_UUID_16_ENCODE ( BT_UUID_BAS_VAL ), 
 BT_UUID_16_ENCODE ( BT_UUID_DIS_VAL )) 
 };

static void bt_ready ( void ) 
 { 
 int err ; 
 
 printk ( "Bluetooth initialized 
 " ); 
 
 err = bt_le_adv_start ( BT_LE_ADV_CONN_NAME , ad , ARRAY_SIZE ( ad ), NULL , 0 ); 
 if ( err ) { 
 printk ( "Advertising failed to start (err %d ) 
 " , err ); 
 return ; 
 } 
 
 printk ( "Advertising successfully started 
 " ); 
 }

RHOOD · Accepted Answer

UPDATE: I managed to figure this out. I havn't gotten this exact implementation to working buy by shoving the device name in the advertisement data and then folding data_cb2 into eir_found I was able to get it printing out the peripheral name. I can share code if anyone would like.

Attempting to print out device name data with "device_found()" in "central_hrs"

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