我正在尝试为 linux 配置蓝牙芯片以与 android 手机配对。我将有一个可以显示 6 位数密码的显示器，因此我正在尝试将 Bluetoothctl 代理设置为 DisplayOnly。
根据这篇文章中的表格https://www.silabs.com/community/wireless/bluetooth/knowledge-base.entry.html/2016/07/11/bt121_-_legacy_pairi-MnCo 如果响应者是 DisplayOnly，发起者 (Android) 是 KeyboardDisplay，它应该使用 Passkey 输入，响应者显示代码，发起者输入代码。
实际发生的情况是 Android 在尝试配对时什么也不显示，而 bluetoothctl 输出显示数字比较响应是/否：即使我指定我没有任何输入 (DisplayOnly)
如何让 bluez 代理真正作为 DisplayOnly 工作，以便它显示一个密码供我在 Android 上输入？
【问题讨论】：
了解 URL 中提到的配对选项是完美的，但 BlueZ 的工作方式不同。此处简单讨论，请参考Bluetooth SIG 的Bluetooth Pairing blog 的解释。
为简化起见，下图是从上述博客中复制而来的。
所以输入可以是“No Input”、“Yes/No”和“Keyboard”三种形式。输出可以是“无输出”和“数值输出”。
在您的情况下，Android 是您要输入显示在响应者中的密钥的发起者。所以 Android 设备的输入是“键盘”，响应者是“数字输出”能力。
要实现您的情况，您需要在响应者中指定“DisplayOnly”（您已经正确）并在输入Android设备中指定“KeyboardOnly”或“KeyboardDisplay”。
但默认情况下，BlueZ 不会将“KeyboardDisplay”视为单独的选项，而是将其转换/视为“DisplayYesNO”，see here in mgmt.txt API 以获取更多详细信息。因此，您的 android 输入设备充当“DisplayYesNo”并导致混乱。
所以你需要在响应端使用“DisplayOnly”，在发起端使用“KeyboardOnly”。要使用自定义代理（不使用 bluetoothctl 的代理）试验此用例，请使用以下示例示例（注意：未完全实现，来自 stdin 的 fscanf 是错误的：-（等，）
/*
* gcc `pkg-config --cflags glib-2.0 gio-2.0` -Wall -Wextra -o ./bin/agent ./agent.c `pkg-config --libs glib-2.0 gio-2.0`
*/
#include <glib.h>
#include <gio/gio.h>
#include <stdio.h>
GMainLoop *loop;
GDBusConnection *con;
#define AGENT_PATH "/org/bluez/AutoPinAgent"
static void bluez_agent_method_call(GDBusConnection *conn,
const gchar *sender,
const gchar *path,
const gchar *interface,
const gchar *method,
GVariant *params,
GDBusMethodInvocation *invocation,
void *userdata)
{
int pass;
int entered;
char *opath;
GVariant *p= g_dbus_method_invocation_get_parameters(invocation);
g_print("Agent method call: %s.%s()\n", interface, method);
if(!strcmp(method, "RequestPinCode")) {
;
}
else if(!strcmp(method, "DisplayPinCode")) {
;
}
else if(!strcmp(method, "RequestPasskey")) {
g_print("Getting the Pin from user: ");
fscanf(stdin, "%d", &pass);
g_print("\n");
g_dbus_method_invocation_return_value(invocation, g_variant_new("(u)", pass));
}
else if(!strcmp(method, "DisplayPasskey")) {
g_variant_get(params, "(ouq)", &opath, &pass, &entered);
g_print("Path: %s Pass: %d Entered: %d\n", opath, pass, entered);
g_dbus_method_invocation_return_value(invocation, NULL);
}
else if(!strcmp(method, "RequestConfirmation")) {
g_variant_get(params, "(ou)", &opath, &pass);
g_print("Path: %s Pass: %d\n", opath, pass);
g_dbus_method_invocation_return_value(invocation, NULL);
}
else if(!strcmp(method, "RequestAuthorization")) {
;
}
else if(!strcmp(method, "AuthorizeService")) {
;
}
else if(!strcmp(method, "Cancel")) {
;
}
else
g_print("We should not come here, unknown method\n");
}
static const GDBusInterfaceVTable agent_method_table = {
.method_call = bluez_agent_method_call,
};
int bluez_register_agent(GDBusConnection *con)
{
GError *error = NULL;
guint id = 0;
GDBusNodeInfo *info = NULL;
static const gchar bluez_agent_introspection_xml[] =
"<node name='/org/bluez/SampleAgent'>"
" <interface name='org.bluez.Agent1'>"
" <method name='Release'>"
" </method>"
" <method name='RequestPinCode'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='s' name='pincode' direction='out' />"
" </method>"
" <method name='DisplayPinCode'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='s' name='pincode' direction='in' />"
" </method>"
" <method name='RequestPasskey'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='u' name='passkey' direction='out' />"
" </method>"
" <method name='DisplayPasskey'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='u' name='passkey' direction='in' />"
" <arg type='q' name='entered' direction='in' />"
" </method>"
" <method name='RequestConfirmation'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='u' name='passkey' direction='in' />"
" </method>"
" <method name='RequestAuthorization'>"
" <arg type='o' name='device' direction='in' />"
" </method>"
" <method name='AuthorizeService'>"
" <arg type='o' name='device' direction='in' />"
" <arg type='s' name='uuid' direction='in' />"
" </method>"
" <method name='Cancel'>"
" </method>"
" </interface>"
"</node>";
info = g_dbus_node_info_new_for_xml(bluez_agent_introspection_xml, &error);
if(error) {
g_printerr("Unable to create node: %s\n", error->message);
g_clear_error(&error);
return 0;
}
id = g_dbus_connection_register_object(con,
AGENT_PATH,
info->interfaces[0],
&agent_method_table,
NULL, NULL, &error);
g_dbus_node_info_unref(info);
//g_dbus_connection_unregister_object(con, id);
/* call register method in AgentManager1 interface */
return id;
}
static int bluez_agent_call_method(const gchar *method, GVariant *param)
{
GVariant *result;
GError *error = NULL;
result = g_dbus_connection_call_sync(con,
"org.bluez",
"/org/bluez",
"org.bluez.AgentManager1",
method,
param,
NULL,
G_DBUS_CALL_FLAGS_NONE,
-1,
NULL,
&error);
if(error != NULL) {
g_print("Register %s: %s\n", AGENT_PATH, error->message);
return 1;
}
g_variant_unref(result);
return 0;
}
static int bluez_register_autopair_agent(const char *cap)
{
int rc;
rc = bluez_agent_call_method("RegisterAgent", g_variant_new("(os)", AGENT_PATH, cap));
if(rc)
return 1;
rc = bluez_agent_call_method("RequestDefaultAgent", g_variant_new("(o)", AGENT_PATH));
if(rc) {
bluez_agent_call_method("UnregisterAgent", g_variant_new("(o)", AGENT_PATH));
return 1;
}
return 0;
}
static void cleanup_handler(int signo)
{
if (signo == SIGINT) {
g_print("received SIGINT\n");
g_main_loop_quit(loop);
}
}
int main(int argc, char **argv)
{
int id;
int rc;
if(argc < 2)
return 1;
if(signal(SIGINT, cleanup_handler) == SIG_ERR)
g_print("can't catch SIGINT\n");
con = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, NULL);
if(con == NULL) {
g_print("Not able to get connection to system bus\n");
return 1;
}
loop = g_main_loop_new(NULL, FALSE);
id = bluez_register_agent(con);
if(id == 0)
goto fail;
rc = bluez_register_autopair_agent(argv[1]);
if(rc) {
g_print("Not able to register default autopair agent\n");
goto fail;
}
g_main_loop_run(loop);
fail:
g_dbus_connection_unregister_object(con, id);
g_object_unref(con);
return 0;
}
要对此进行实验，您必须在 bluetoothctl "agent off" 中禁用代理并打开代理，
Responder: ./bin/agent "DisplayOnly"
Initiator: ./bin/agent "KeyboardOnly"
当您尝试从发起方配对时，DisplayPasskey 将在响应方中调用并显示 6 位 PIN，发起方将调用 RequestPasskey 并从标准输入获取输入 PIN。
【讨论】：