为什么使用 ADV_DATA 的广告会产生无效参数

Question

我正在尝试使用管理编写一些 BlueZ 代码API，但我似乎无法让 BlueZ 在广告系统上宣传任意数据

我有 2 个测试，一个在 C++ 中，一个使用 BlueZ 发布的 btmgmt 工具

当我运行这个命令失败时

btmgmt add-adv -d 8C33 1
Add Advertising failed with status 0x0d (Invalid Parameters)

等效的 C++ 代码也同样失败

#include <iostream>

extern "C" {
  #include "external/bluetooth/lib/bluetooth.h"
  #include "external/bluetooth/lib/mgmt.h"
  #include "external/bluetooth/lib/hci.h"
  #include "external/bluetooth/lib/hci_lib.h"
  #include "external/bluetooth/src/shared/mgmt.h"
}

static void setup_dv(uint8_t status, uint16_t length,
                     const void *param, void *user_data)
{
  std::cout << "good" << std::endl;
}

struct CPadvertising {
        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[4];
} __packed;


int main()
{
  mgmt* sock =  mgmt_new_default();


  CPadvertising* data = new CPadvertising();

  data->instance = 1;
  data->duration = 2;
  data->timeout = 100;
  data->adv_data_len = 4;
  data->scan_rsp_len = 0;
  data->flags = 0;
  data->data[0] = 8;
  data->data[1] = 12;
  data->data[2] = 3;
  data->data[3] = 3;

  mgmt_send(sock, MGMT_OP_ADD_ADVERTISING, index, 
  sizeof(CPadvertising), data, setup_dv, nullptr, nullptr);
  auto  loop = g_main_loop_new(nullptr, FALSE);
  g_main_loop_run(loop);

}

在 btmon

中有此输出

@ MGMT Command: Add Advertising (0x003e) plen 13                               {0x0003} [hci0] 98.205359
        Instance: 1
        Flags: 0x00000000
        Duration: 2
        Timeout: 100
        Advertising data length: 4
        8 c 3 3                                            .3              
        Scan response length: 0
@ MGMT Event: Command Status (0x0002) plen 3                                   {0x0003} [hci0] 98.205376
      Add Advertising (0x003e)
        Status: Invalid Parameters (0x0d)

参考这些文档，我不应该得到任何无效参数，但我确实如此

https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/mgmt-api.txt

但是，我知道某些类型的数据确实有效

btmgmt add-adv -d 080954657374204C45

甚至以一种更奇怪的方式在 btmon

上提示这个输出

@ MGMT Command: Add Advertising (0x003e) plen 20                              {0x0002} [hci0] 143.671485
        Instance: 1
        Flags: 0x00000000
        Duration: 0
        Timeout: 0
        Advertising data length: 9
        Name (complete): Test LL <--- What is this
        Scan response length: 0

Answer 1

查看 btmgmt 的源代码，这些是可用的选项：

static void add_adv_usage(void)
{
    bt_shell_usage();
    print("Options:\n"
        "\t -u, --uuid <uuid>         Service UUID\n"
        "\t -d, --adv-data <data>     Advertising Data bytes\n"
        "\t -s, --scan-rsp <data>     Scan Response Data bytes\n"
        "\t -t, --timeout <timeout>   Timeout in seconds\n"
        "\t -D, --duration <duration> Duration in seconds\n"
        "\t -P, --phy <phy>           Phy type, Specify 1M/2M/CODED\n"
        "\t -c, --connectable         \"connectable\" flag\n"
        "\t -g, --general-discov      \"general-discoverable\" flag\n"
        "\t -l, --limited-discov      \"limited-discoverable\" flag\n"
        "\t -n, --scan-rsp-local-name \"local-name\" flag\n"
        "\t -a, --scan-rsp-appearance \"appearance\" flag\n"
        "\t -m, --managed-flags       \"managed-flags\" flag\n"
        "\t -p, --tx-power            \"tx-power\" flag\n"
        "e.g.:\n"
        "\tadd-adv -u 180d -u 180f -d 080954657374204C45 1");
}

查看有效的广告，第一个数字是数据的长度，第二个是data_type，其余是local name 字符串。所以：

0x08 = Length of datatype is 8
0x09 = Data type is <Complete Local Name>
0x54 = T
0x65 = e
0x73 = s
0x74 = t
0x20 = ' ' 
0x4C = L
0x45 = E

Not sure why that has turned up as Test LL in the btmon output. I'll assume it was a slightly different run that you recorded.

正在查看您 8c33 的数据； 8c 不代表长度，33 不是有效的数据类型。

我怀疑你想做的是发送制造商数据。假设您没有 company identifier，那么您可以使用 0xffff 进行测试。

这将是以下命令：

btmgmt add-adv -d 05ffffff8C33 -g 1

在 btmon 中给出了以下内容

@ MGMT Command: Add Adver.. (0x003e) plen 17  {0x0002} [hci0] 341.378134
        Instance: 1
        Flags: 0x00000002
          Advertise as Discoverable
        Duration: 0
        Timeout: 0
        Advertising data length: 6
        Company: internal use (65535)
          Data: 8c33
        Scan response length: 0

为什么使用 ADV_DATA 的广告会产生无效参数

Why is advertising with ADV_DATA producing Invalid Parameters

c++

bluetooth