Extract MTU workaround into function

bluez · Sep 13, 2023 · 2452e15 · 2452e15
1 parent bf4ed3b
commit 2452e15
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Showing 3 changed files with 15 additions and 9 deletions.
diff --git a/bluer/src/gatt/local.rs b/bluer/src/gatt/local.rs
@@ -25,8 +25,8 @@ use tokio_stream::wrappers::ReceiverStream;
 use uuid::Uuid;
 
 use super::{
-    make_socket_pair, CharacteristicFlags, CharacteristicReader, CharacteristicWriter, DescriptorFlags, WriteOp,
-    CHARACTERISTIC_INTERFACE, DESCRIPTOR_INTERFACE, SERVICE_INTERFACE,
+    make_socket_pair, mtu_workaround, CharacteristicFlags, CharacteristicReader, CharacteristicWriter,
+    DescriptorFlags, WriteOp, CHARACTERISTIC_INTERFACE, DESCRIPTOR_INTERFACE, SERVICE_INTERFACE,
 };
 use crate::{
     method_call, parent_path, Adapter, Address, DbusResult, Device, Error, ErrorKind, Result, SessionInner,
@@ -942,8 +942,7 @@ impl RegisteredCharacteristic {
                                 // BlueZ has already confirmed the start of the notification session.
                                 // So there is no point in making this fail-able by our users.
                                 let (fd, stream) = make_socket_pair(true).map_err(|_| ReqError::Failed)?;
-                                // WORKAROUND: BlueZ drops data at end of packet if full MTU is used.
-                                let mtu = options.mtu.saturating_sub(5).into();
+                                let mtu = mtu_workaround(options.mtu.into());
                                 let writer = CharacteristicWriter {
                                     adapter_name: options.adapter_name.clone(),
                                     device_address: options.device_address,

diff --git a/bluer/src/gatt/mod.rs b/bluer/src/gatt/mod.rs
@@ -354,3 +354,11 @@ pub(crate) fn make_socket_pair(non_block: bool) -> std::io::Result<(OwnedFd, Uni
 
     Ok((fd1, us))
 }
+
+/// Apply MTU workaround.
+///
+/// BlueZ drops data at end of packet if full reported MTU is used, thus we
+/// substract 5 bytes to workaround this issue.
+pub(crate) fn mtu_workaround(mtu: usize) -> usize {
+    mtu.saturating_sub(5)
+}
diff --git a/bluer/src/gatt/remote.rs b/bluer/src/gatt/remote.rs
@@ -11,8 +11,8 @@ use tokio::net::UnixStream;
 use uuid::Uuid;
 
 use super::{
-    CharacteristicFlags, CharacteristicReader, CharacteristicWriter, WriteOp, CHARACTERISTIC_INTERFACE,
-    DESCRIPTOR_INTERFACE, SERVICE_INTERFACE,
+    mtu_workaround, CharacteristicFlags, CharacteristicReader, CharacteristicWriter, WriteOp,
+    CHARACTERISTIC_INTERFACE, DESCRIPTOR_INTERFACE, SERVICE_INTERFACE,
 };
 use crate::{
     all_dbus_objects, Address, Device, Error, ErrorKind, Event, InternalErrorKind, Result, SessionInner,
@@ -354,8 +354,7 @@ impl Characteristic {
         let stream = unsafe { std::os::unix::net::UnixStream::from_raw_fd(fd.into_fd()) };
         stream.set_nonblocking(true)?;
         let stream = UnixStream::from_std(stream)?;
-        // WORKAROUND: BlueZ drops data at end of packet if full MTU is used.
-        let mtu = mtu.saturating_sub(5).into();
+        let mtu = mtu_workaround(mtu.into());
         Ok(CharacteristicWriter {
             adapter_name: self.adapter_name().to_string(),
             device_address: self.device_address,
@@ -541,7 +540,7 @@ define_properties!(
         property(
             Mtu, usize,
             dbus: (CHARACTERISTIC_INTERFACE, "MTU", u16, MANDATORY),
-            get: (mtu, v => { (*v).into() }),
+            get: (mtu, v => { mtu_workaround((*v).into()) }),
         );
     }
 );