如何使用像hcitool lescan这样的bluetoothctl来报告重复的接近信标

Question

我可以使用带有--duplicates标志的hcitool lescan来捕获来自附近两个BLE设备的定期LE广告报告(接近信标):

$ sudo hcitool lescan --duplicates
LE Scan ...
C8:0F:10:29:4D:98 MI1S
C8:0F:10:29:4E:75 MI1S
C8:0F:10:29:4E:75 MI1S
C8:0F:10:29:4D:98 MI1S
C8:0F:10:29:4E:75 MI1S
C8:0F:10:29:4D:98 MI1S
<snip>

这是再次扫描,添加时间戳以显示周期:

$ sudo stdbuf -i0 -o0 -e0 hcitool lescan --duplicates | perl -nle 'print scalar(localtime), " ", $_'
Wed Apr 13 13:46:45 2016 LE Scan ...
Wed Apr 13 13:46:46 2016 C8:0F:10:29:4E:75 MI1S
Wed Apr 13 13:46:47 2016 C8:0F:10:29:4D:98 MI1S
Wed Apr 13 13:46:48 2016 C8:0F:10:29:4E:75 MI1S
Wed Apr 13 13:46:48 2016 C8:0F:10:29:4D:98 MI1S
Wed Apr 13 13:46:50 2016 C8:0F:10:29:4D:98 MI1S
Wed Apr 13 13:46:52 2016 C8:0F:10:29:4E:75 MI1S
<snip>

在上周(2016年4月)的嵌入式Linux会议和物联网峰会上,一位在BlueZ堆栈上工作的演示者表示不再使用hcitool,而是使用bluetoothctl.

我今天试过了,但它只显示了设备的第一个LE广告报告(如hcitool没有--duplicates选项):

$ sudo bluetoothctl
[NEW] Controller 5C:F3:70:62:68:28 BlueZ 5.38 [default]

[bluetooth]# power on
Changing power on succeeded
[CHG] Controller 5C:F3:70:62:68:28 Powered: yes

[bluetooth]# scan on
Discovery started
[CHG] Controller 5C:F3:70:62:68:28 Discovering: yes
[CHG] Device C8:0F:10:29:4E:75 RSSI: -72
[CHG] Device C8:0F:10:29:4D:98 RSSI: -65

[bluetooth]# devices
Device C8:0F:10:29:4D:98 MI1S
Device C8:0F:10:29:4E:75 MI1S

如何使用bluetoothctl从同一设备捕获重复的LE广告报告,如hcitool与--duplicates选项一样？

Answer 1

感谢弗洛里安的建议。

自从我的原始帖子以来，我已迁移到包含 bluez 5.42 的 Ubuntu 16.04.4 嵌入式 Linux 发行版。不幸的是，此版本的 bluetoothctl 无法识别“菜单扫描”或“清除”：

[bluetooth]# menu scan
Invalid command

[bluetooth]# clear
Invalid command

但是，由于您提到“阻止大多数广告的默认扫描过滤器处于活动状态”而受到鼓舞，我试验了我的 bluetoothctl 版本中可用的命令，如 --help 输出中所示，并得到了一些工作：

root@iot:~# bluetoothctl
[NEW] Controller 00:1A:7D:DA:71:13 iot #1 [default]
[NEW] Controller 70:2C:1F:31:F4:AF iot 

[bluetooth]# set-scan-filter-clear
SetDiscoveryFilter success

[bluetooth]# set-scan-filter-transport le
SetDiscoveryFilter success

[bluetooth]# scan on
Discovery started

[CHG] Controller 00:1A:7D:DA:71:13 Discovering: yes
[NEW] Device 0F:64:64:EE:E7:C4 0F-64-64-EE-E7-C4
[NEW] Device 0D:6F:45:77:87:F3 0D-6F-45-77-87-F3
[NEW] Device 40:CB:C0:F2:96:27 40-CB-C0-F2-96-27
[CHG] Device 0D:6F:45:77:87:F3 RSSI: -71
[CHG] Device FC:F1:36:73:77:B3 RSSI: -57
[CHG] Device 0F:64:64:EE:E7:C4 RSSI: -49

需要在 bluetoothctl 中输入一些内容才能按照我想要的方式对其进行配置，并且在我们的信标丰富的环境中，bluetoothctl 日志记录活动会迅速掩盖这种输入。所以我整理了一个使用 heredoc 的 bash 脚本，并期望将命令提供给 bluetoothctl 和 sed/grep/perl 按摩输出：

$ cat beacon-scan.sh 
#!/bin/bash

# beacon-scan.sh
# Displays beacons including duplicates in real time.
# Uses expect to automate interaction with bluetoothctl.
# Uses sed to remove bluetoothctl colorization escape characters.
# Uses grep to filter out beacon manufacturer data logging.
# Uses perl to prefix each beacon with a timestamp.

if [ "$(id -u)" != "0" ]; then
    echo "ERROR: must run as root"
    exit 1
fi

(cat <<'END' | /usr/bin/expect

    set prompt "#"
    set timeout -1

    spawn bluetoothctl

    expect -re $prompt
    send "scan off\r"

    expect -re $prompt
    send "remove *\r"

    expect -re $prompt
    send "set-scan-filter-clear\r"

    expect -re $prompt
    send "set-scan-filter-transport le\r"

    expect -re $prompt
    send "scan on\r"

    trap {
        expect -re $prompt
        send "scan off\r"

        expect -re $prompt
        send "remove *\r"

        expect -re $prompt
        send "quit\r"
    } SIGINT

    expect eof

END
) | sed --unbuffered --quiet --expression 's/^.*Device //p' \
  | grep --line-buffered -v ManufacturerData \
  | perl -nle 'print scalar(localtime), " ", $_'

有用：

$ sudo ./beacon-scan.sh 
Wed Aug 22 19:34:07 2018 0F:64:64:EE:E7:C4 RSSI: -59
Wed Aug 22 19:34:07 2018 03:46:00:1D:E9:91 03-46-00-1D-E9-91
Wed Aug 22 19:34:07 2018 4E:20:6B:C7:68:D0 RSSI: -55
Wed Aug 22 19:34:07 2018 76:F1:1A:B9:ED:28 RSSI: -57
Wed Aug 22 19:34:07 2018 32:5D:8C:6A:72:C2 32-5D-8C-6A-72-C2
^C

重复的信标现在由 bluetoothctl 报告，类似于 hcitool lescan 使用重复标志运行时。

我会说，如果可以从命令行配置 bluetoothctl 而不需要交互式配置它或不得不求助于更复杂的脚本，那么它会更容易使用。

感谢弗洛里安的帮助。

Answer 2

刚刚发现以下对我有用（Ubuntu 18.04.1，bluez 5.48）：

$ bluetoothctl
[bluetooth]# scan on
[bluetooth]# menu scan
[bluetooth]# clear
SetDiscoveryFilter success
[NEW] Device de:ad:be:ef:ca:fe SampleDev
[CHG] Device de:ad:be:ef:ca:fe RSSI: -73
[CHG] Device de:ad:be:ef:ca:fe RSSI: -73
[CHG] Device de:ad:be:ef:ca:fe RSSI: -74

看起来有一个默认的扫描过滤器处于活动状态，可以阻止大多数广告。