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From: Yunhan Wang <yunhanw@google.com>
Date: Tue, 1 Aug 2017 00:37:29 -0700
Message-ID: <CALvjcs8cbrO1sE_bgKXsLZ6C5omO=Y_duXjkRC1Rww-z156v9w@mail.gmail.com>
Subject: how to add local name in scan response when setting
 MGMT_ADV_FLAG_LOCAL_NAME in Bluez
To: linux-bluetooth@vger.kernel.org
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Hi

I am trying to do some small experiments that add local name in the
scan response,  should I use data[0] to store both adv_data and
scan_rsp?

I tried to add local name(=E2=80=99TEST=E2=80=99) in data[0] under
mgmt_cp_add_advertising on
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/advertising.c#n=
484,
it seems it does not work, any idea?

Thanks
Best wishes
Yunhan

static DBusMessage *refresh_advertisement(struct btd_adv_client *client)
{
struct mgmt_cp_add_advertising *cp;
uint8_t param_len;
uint8_t *adv_data;
size_t adv_data_len;
uint32_t flags =3D 0;

uint8_t scan_rsp[] =3D {
=E2=80=99T=E2=80=99,
=E2=80=99E=E2=80=99,
=E2=80=99S=E2=80=99,
=E2=80=99T=E2=80=99
};
size_t scan_rsp_len =3D sizeof(scan_rsp);

DBG("Refreshing advertisement: %s", client->path);

if (client->type =3D=3D AD_TYPE_PERIPHERAL)
flags =3D MGMT_ADV_FLAG_CONNECTABLE | MGMT_ADV_FLAG_DISCOV |
MGMT_ADV_FLAG_LOCAL_NAME;

if (client->include_tx_power)
flags |=3D MGMT_ADV_FLAG_TX_POWER;

adv_data =3D bt_ad_generate(client->data, &adv_data_len);

if (!adv_data || (adv_data_len > calc_max_adv_len(client, flags))) {
error("Advertising data too long or couldn't be generated.");

return g_dbus_create_error(client->reg, ERROR_INTERFACE
".InvalidLength",
"Advertising data too long.");
}

param_len =3D sizeof(struct mgmt_cp_add_advertising) + adv_data_len +
scan_rsp_len;

cp =3D malloc0(param_len);

if (!cp) {
error("Couldn't allocate for MGMT!");

free(adv_data);

return btd_error_failed(client->reg, "Failed");
}

cp->flags =3D htobl(flags);
cp->instance =3D client->instance;
cp->adv_data_len =3D adv_data_len;
cp->scan_rsp_len =3D scan_rsp_len;
memcpy(cp->data, adv_data, adv_data_len);
memcpy(cp->data + adv_data_len, scan_rsp_data, scan_rsp_len);
free(adv_data);

if (!mgmt_send(client->manager->mgmt, MGMT_OP_ADD_ADVERTISING,
client->manager->mgmt_index, param_len, cp,
add_adv_callback, client, NULL)) {
DBG("Failed to add Advertising Data");

free(cp);

return btd_error_failed(client->reg, "Failed");
}

free(cp);

return NULL;
}

Reference:
In lib/mgmt.h,

#define MGMT_OP_ADD_ADVERTISING 0x003E
struct mgmt_cp_add_advertising {
uint8_t  instance;
uint32_t flags;
uint16_t duration;
uint16_t timeout;
uint8_t  adv_data_len;
uint8_t  scan_rsp_len;
uint8_t  data[0];
} __packed;
>From mgmt-api.txt, I am

Add Advertising Command
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Command Code: 0x003e
Controller Index: <controller id>
Command Parameters: Instance (1 Octet)
Flags (4 Octets)
Duration (2 Octets)
Timeout (2 Octets)
Adv_Data_Len (1 Octet)
Scan_Rsp_len (1 Octet)
Adv_Data (0-255 Octets)
Scan_Rsp (0-255 Octets)
=E2=80=A6...
With the Flags value the type of advertising is controlled and
the following flags are defined:

0 Switch into Connectable mode
1 Advertise as Discoverable
2 Advertise as Limited Discoverable
3 Add Flags field to Adv_Data
4 Add TX Power field to Adv_Data
5 Add Appearance field to Scan_Rsp
6 Add Local Name in Scan_Rsp