To use netlink from Rust Binder, add a new generated netlink file using
the new script and Documentation/netlink/specs/binder.yaml.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 drivers/android/Kconfig                    |   2 +-
 drivers/android/binder/netlink.rs          | 113 +++++++++++++++++++++++++++++
 drivers/android/binder/rust_binder_main.rs |   9 ++-
 rust/uapi/uapi_helper.h                    |   1 +
 4 files changed, 122 insertions(+), 3 deletions(-)

diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig
index e2e402c9d175..606a9d07f774 100644
--- a/drivers/android/Kconfig
+++ b/drivers/android/Kconfig
@@ -16,7 +16,7 @@ config ANDROID_BINDER_IPC
 
 config ANDROID_BINDER_IPC_RUST
 	bool "Rust version of Android Binder IPC Driver"
-	depends on RUST && MMU && !ANDROID_BINDER_IPC
+	depends on RUST && MMU && NET && !ANDROID_BINDER_IPC
 	help
 	  This enables the Rust implementation of the Binder driver.
 
diff --git a/drivers/android/binder/netlink.rs b/drivers/android/binder/netlink.rs
new file mode 100644
index 000000000000..0537be08f4d5
--- /dev/null
+++ b/drivers/android/binder/netlink.rs
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/binder.yaml */
+/* YNL-GEN rust source */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#![allow(unreachable_pub, clippy::wrong_self_convention)]
+use kernel::netlink::{Family, MulticastGroup};
+use kernel::prelude::*;
+
+pub static BINDER_NL_FAMILY: Family = Family::const_new(
+    &crate::THIS_MODULE,
+    kernel::uapi::BINDER_FAMILY_NAME,
+    kernel::uapi::BINDER_FAMILY_VERSION,
+    &BINDER_NL_FAMILY_MCGRPS,
+);
+
+static BINDER_NL_FAMILY_MCGRPS: [MulticastGroup; 1] = [MulticastGroup::const_new(c"report")];
+
+/// A multicast event sent to userspace subscribers to notify them about
+/// binder transaction failures. The generated report provides the full
+/// details of the specific transaction that failed. The intention is for
+/// programs to monitor these events and react to the failures as needed.
+pub struct Report {
+    skb: kernel::netlink::GenlMsg,
+}
+
+impl Report {
+    /// Create a new multicast message.
+    pub fn new(
+        size: usize,
+        portid: u32,
+        seq: u32,
+        flags: kernel::alloc::Flags,
+    ) -> Result<Self, kernel::alloc::AllocError> {
+        const BINDER_CMD_REPORT: u8 = kernel::uapi::BINDER_CMD_REPORT as u8;
+        let skb = kernel::netlink::SkBuff::new(size, flags)?;
+        let skb = skb.genlmsg_put(portid, seq, &BINDER_NL_FAMILY, BINDER_CMD_REPORT)?;
+        Ok(Self { skb })
+    }
+
+    /// Broadcast this message.
+    pub fn multicast(self, portid: u32, flags: kernel::alloc::Flags) -> Result {
+        self.skb.multicast(&BINDER_NL_FAMILY, portid, 0, flags)
+    }
+
+    /// Check if this message type has listeners.
+    pub fn has_listeners() -> bool {
+        BINDER_NL_FAMILY.has_listeners(0)
+    }
+
+    /// The enum binder_driver_return_protocol returned to the sender.
+    pub fn error(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_ERROR: c_int = kernel::uapi::BINDER_A_REPORT_ERROR as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_ERROR, val)
+    }
+
+    /// The binder context where the transaction occurred.
+    pub fn context(&mut self, val: &CStr) -> Result {
+        const BINDER_A_REPORT_CONTEXT: c_int = kernel::uapi::BINDER_A_REPORT_CONTEXT as c_int;
+        self.skb.put_string(BINDER_A_REPORT_CONTEXT, val)
+    }
+
+    /// The PID of the sender process.
+    pub fn from_pid(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_FROM_PID: c_int = kernel::uapi::BINDER_A_REPORT_FROM_PID as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_FROM_PID, val)
+    }
+
+    /// The TID of the sender thread.
+    pub fn from_tid(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_FROM_TID: c_int = kernel::uapi::BINDER_A_REPORT_FROM_TID as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_FROM_TID, val)
+    }
+
+    /// The PID of the recipient process. This attribute may not be present
+    /// if the target could not be determined.
+    pub fn to_pid(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_TO_PID: c_int = kernel::uapi::BINDER_A_REPORT_TO_PID as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_TO_PID, val)
+    }
+
+    /// The TID of the recipient thread. This attribute may not be present
+    /// if the target could not be determined.
+    pub fn to_tid(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_TO_TID: c_int = kernel::uapi::BINDER_A_REPORT_TO_TID as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_TO_TID, val)
+    }
+
+    /// When present, indicates the failed transaction is a reply.
+    pub fn is_reply(&mut self) -> Result {
+        const BINDER_A_REPORT_IS_REPLY: c_int = kernel::uapi::BINDER_A_REPORT_IS_REPLY as c_int;
+        self.skb.put_flag(BINDER_A_REPORT_IS_REPLY)
+    }
+
+    /// The bitmask of enum transaction_flags from the transaction.
+    pub fn flags(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_FLAGS: c_int = kernel::uapi::BINDER_A_REPORT_FLAGS as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_FLAGS, val)
+    }
+
+    /// The application-defined code from the transaction.
+    pub fn code(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_CODE: c_int = kernel::uapi::BINDER_A_REPORT_CODE as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_CODE, val)
+    }
+
+    /// The transaction payload size in bytes.
+    pub fn data_size(&mut self, val: u32) -> Result {
+        const BINDER_A_REPORT_DATA_SIZE: c_int = kernel::uapi::BINDER_A_REPORT_DATA_SIZE as c_int;
+        self.skb.put_u32(BINDER_A_REPORT_DATA_SIZE, val)
+    }
+}
diff --git a/drivers/android/binder/rust_binder_main.rs b/drivers/android/binder/rust_binder_main.rs
index aa5f2a75adb4..65dae8931676 100644
--- a/drivers/android/binder/rust_binder_main.rs
+++ b/drivers/android/binder/rust_binder_main.rs
@@ -36,6 +36,8 @@
 mod deferred_close;
 mod defs;
 mod error;
+#[allow(dead_code)]
+mod netlink;
 mod node;
 mod page_range;
 mod process;
@@ -285,7 +287,9 @@ fn ptr_align(value: usize) -> Option<usize> {
 // SAFETY: We call register in `init`.
 static BINDER_SHRINKER: Shrinker = unsafe { Shrinker::new() };
 
-struct BinderModule {}
+struct BinderModule {
+    _netlink: kernel::netlink::Registration,
+}
 
 impl kernel::Module for BinderModule {
     fn init(_module: &'static kernel::ThisModule) -> Result<Self> {
@@ -294,12 +298,13 @@ fn init(_module: &'static kernel::ThisModule) -> Result<Self> {
 
         pr_warn!("Loaded Rust Binder.");
 
+        let netlink = crate::netlink::BINDER_NL_FAMILY.register()?;
         BINDER_SHRINKER.register(c"android-binder")?;
 
         // SAFETY: The module is being loaded, so we can initialize binderfs.
         unsafe { kernel::error::to_result(binderfs::init_rust_binderfs())? };
 
-        Ok(Self {})
+        Ok(Self { _netlink: netlink })
     }
 }
 
diff --git a/rust/uapi/uapi_helper.h b/rust/uapi/uapi_helper.h
index 06d7d1a2e8da..86c7b6b284b0 100644
--- a/rust/uapi/uapi_helper.h
+++ b/rust/uapi/uapi_helper.h
@@ -11,6 +11,7 @@
 #include <uapi/drm/nova_drm.h>
 #include <uapi/drm/panthor_drm.h>
 #include <uapi/linux/android/binder.h>
+#include <uapi/linux/android/binder_netlink.h>
 #include <uapi/linux/mdio.h>
 #include <uapi/linux/mii.h>
 #include <uapi/linux/ethtool.h>

-- 
2.53.0.473.g4a7958ca14-goog

"Alice Ryhl" <aliceryhl@google.com> writes:

> To use netlink from Rust Binder, add a new generated netlink file using
> the new script and Documentation/netlink/specs/binder.yaml.
>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Does this have to be in tree? Can't we run the generator during build?


Best regards,
Andreas Hindborg