Add Linux and CoreBluetooth L2Cap Channels

Cargo.toml

@@ -21,6 +21,7 @@ targets = [
 
 [features]
 serde = ["dep:serde", "uuid/serde", "bluer/serde"]
+l2cap = ["dep:tokio", "bluer/l2cap"]
 
 [dependencies]
 async-trait = "0.1.57"
@@ -30,7 +31,12 @@ serde = { version = "1.0.143", optional = true, features = ["derive"] }
 tracing = { version = "0.1.36", default-features = false }
 
 [dev-dependencies]
-tokio = { version = "1.20.1", features = ["macros", "rt-multi-thread", "time"] }
+tokio = { version = "1.20.1", features = [
+    "macros",
+    "rt-multi-thread",
+    "time",
+    "io-util",
+] }
 tracing-subscriber = { version = "0.3.15", features = ["env-filter"] }
 
 [target.'cfg(not(target_os = "linux"))'.dependencies]
@@ -57,13 +63,19 @@ tokio = { version = "1.20.1", features = ["rt-multi-thread"] }
 [target.'cfg(target_os = "android")'.dependencies]
 java-spaghetti = "0.2.0"
 async-channel = "2.2.0"
+tokio = { version = "1.20.1", features = ["rt", "io-util"], optional = true }
 
 [target.'cfg(any(target_os = "macos", target_os = "ios"))'.dependencies]
 async-broadcast = "0.5.1"
 objc = "0.2.7"
 objc_id = "0.1.1"
 objc-foundation = "0.1.1"
+tokio = { version = "1.20.1", features = ["net"], optional = true }
 
 [[example]]
 name = "scan"
 doc-scrape-examples = true
+
+[[example]]
+name = "l2cap_client"
+required-features = ["l2cap"]

README.md

@@ -99,6 +99,7 @@ below.
 | [`Device::pair_with_agent`][Device::pair_with_agent]             |    ✨     |   ✅    |  ✅   |
 | [`Device::unpair`][Device::unpair]                               |    ❌     |   ✅    |  ✅   |
 | [`Device::rssi`][Device::rssi]                                   |    ✅     |   ❌    |  ❌   |
+| [`Device::open_l2cap_channel`][Device::open_l2cap_channel]       |    ⌛️     |   ❌    |  ⌛️   |
 | [`Service::uuid`][Service::uuid]                                 |    ✅     |   ✅    |  ⌛️   |
 | [`Service::is_primary`][Service::is_primary]                     |    ✅     |   ❌    |  ✅   |
 | [`Characteristic::uuid`][Characteristic::uuid]                   |    ✅     |   ✅    |  ⌛️   |
@@ -149,6 +150,7 @@ Refer to the [API documentation] for more details.
 [Device::unpair]: https://docs.rs/bluest/latest/bluest/struct.Device.html#method.unpair
 [Device::discover_services]: https://docs.rs/bluest/latest/bluest/struct.Device.html#method.discover_services
 [Device::rssi]: https://docs.rs/bluest/latest/bluest/struct.Device.html#method.rssi
+[Device::open_l2cap_channel]: https://docs.rs/bluest/latest/bluest/struct.Device.html#method.open_l2cap_channel
 [Service::uuid]: https://docs.rs/bluest/latest/bluest/struct.Service.html#method.uuid
 [Service::is_primary]: https://docs.rs/bluest/latest/bluest/struct.Service.html#method.is_primary
 [Service::discover_characteristics]: https://docs.rs/bluest/latest/bluest/struct.Service.html#method.discover_characteristics

examples/l2cap_client.rs

@@ -0,0 +1,64 @@
+// This is designed to be used in conjunction with the l2cap_server example from bluer. https://github.com/bluez/bluer/blob/869dab889140e3be5a0f1791c40825730893c8b6/bluer/examples/l2cap_server.rs
+
+use std::error::Error;
+
+use bluest::{Adapter, Uuid as BluestUUID};
+use futures_lite::StreamExt;
+use tokio::io::AsyncReadExt;
+use tracing::info;
+use tracing::metadata::LevelFilter;
+
+#[cfg(target_os = "linux")]
+const SERVICE_UUID: BluestUUID = bluer::Uuid::from_u128(0xFEED0000F00D);
+
+#[cfg(not(target_os = "linux"))]
+use uuid::Uuid;
+#[cfg(not(target_os = "linux"))]
+const SERVICE_UUID: BluestUUID = Uuid::from_u128(0xFEED0000F00D);
+
+const PSM: u16 = 0x80 + 5;
+
+const HELLO_MSG: &[u8] = b"Hello from l2cap_server!";
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    use tracing_subscriber::prelude::*;
+    use tracing_subscriber::{fmt, EnvFilter};
+
+    tracing_subscriber::registry()
+        .with(fmt::layer())
+        .with(
+            EnvFilter::builder()
+                .with_default_directive(LevelFilter::INFO.into())
+                .from_env_lossy(),
+        )
+        .init();
+
+    let adapter = Adapter::default().await.unwrap();
+    adapter.wait_available().await?;
+
+    info!("looking for device");
+    let device = adapter
+        .discover_devices(&[SERVICE_UUID])
+        .await?
+        .next()
+        .await
+        .ok_or("Failed to discover device")??;
+    info!(
+        "found device: {} ({:?})",
+        device.name().as_deref().unwrap_or("(unknown)"),
+        device.id()
+    );
+
+    adapter.connect_device(&device).await.unwrap();
+
+    let mut channel = device.open_l2cap_channel(PSM, true).await.unwrap();
+
+    info!("Reading from channel.");
+    let mut hello_buf = [0u8; HELLO_MSG.len()];
+    channel.read_exact(&mut hello_buf).await.unwrap();
+
+    info!("Got {} from channel", std::str::from_utf8(&hello_buf).unwrap());
+    assert_eq!(hello_buf, HELLO_MSG);
+    Ok(())
+}

src/android/device.rs

@@ -4,13 +4,14 @@ use java_spaghetti::Global;
 use uuid::Uuid;
 
 use super::bindings::android::bluetooth::BluetoothDevice;
-use super::l2cap_channel::{L2capChannelReader, L2capChannelWriter};
 use crate::pairing::PairingAgent;
 use crate::{DeviceId, Result, Service, ServicesChanged};
 
 #[derive(Clone)]
 pub struct DeviceImpl {
     pub(super) id: DeviceId,
+
+    #[allow(unused)]
     pub(super) device: Global<BluetoothDevice>,
 }
 
@@ -97,12 +98,9 @@ impl DeviceImpl {
         todo!()
     }
 
-    pub async fn open_l2cap_channel(
-        &self,
-        psm: u16,
-        secure: bool,
-    ) -> std::prelude::v1::Result<(L2capChannelReader, L2capChannelWriter), crate::Error> {
-        super::l2cap_channel::open_l2cap_channel(self.device.clone(), psm, secure)
+    #[cfg(feature = "l2cap")]
+    pub async fn open_l2cap_channel(&self, psm: u16, secure: bool) -> Result<super::l2cap_channel::Channel> {
+        super::l2cap_channel::Channel::new(self.device.clone(), psm, secure)
     }
 }