[PATCH v2 4/5] samples: rust: add dummy network driver

[FUJITA Tomonori <fujita.tomonori@gmail.com>]

This is a simpler version of drivers/net/dummy.c.

This demonstrates the usage of abstractions for network device drivers.

Allows allocator_api feature for Box::try_new();

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 samples/rust/Kconfig           | 13 ++++++
 samples/rust/Makefile          |  1 +
 samples/rust/rust_net_dummy.rs | 75 ++++++++++++++++++++++++++++++++++
 scripts/Makefile.build         |  2 +-
 4 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 samples/rust/rust_net_dummy.rs

diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index b0f74a81c8f9..02bda7bdf722 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -30,6 +30,19 @@ config SAMPLE_RUST_PRINT
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_NET_DUMMY
+	tristate "Dummy network driver"
+	depends on NET
+	help
+	  This is the simpler version of drivers/net/dummy.c.
+	  No intention to replace it. This provides educational information
+	  for Rust abstractions for network device drivers.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_net_dummy.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_HOSTPROGS
 	bool "Host programs"
 	help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..440dee2971ba 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -2,5 +2,6 @@
 
 obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
 obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_NET_DUMMY)		+= rust_net_dummy.o
 
 subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/rust_net_dummy.rs b/samples/rust/rust_net_dummy.rs
new file mode 100644
index 000000000000..78f8f3321fd2
--- /dev/null
+++ b/samples/rust/rust_net_dummy.rs
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+//! Rust dummy netdev.
+
+//use kernel::types::ForeignOwnable;
+use kernel::{
+    c_str,
+    net::dev::{
+        flags, priv_flags, Device, DeviceOperations, EtherOperations, EthtoolTsInfo, Registration,
+        SkBuff, TxCode,
+    },
+    prelude::*,
+};
+
+module! {
+    type: DummyNetdev,
+    name: "rust_net_dummy",
+    author: "Rust for Linux Contributors",
+    description: "Rust dummy netdev",
+    license: "GPL v2",
+}
+
+#[vtable]
+impl DeviceOperations for Box<DriverData> {
+    fn init(dev: Device<Box<DriverData>>) -> Result {
+        // how to access to the driver private data.
+        let _ = dev.drv_priv_data();
+        Ok(())
+    }
+
+    fn start_xmit(_dev: Device<Box<DriverData>>, mut skb: SkBuff) -> TxCode {
+        skb.tx_timestamp();
+        skb.consume();
+        TxCode::Ok
+    }
+}
+
+/// For device driver specific information.
+struct DriverData {}
+
+struct DummyNetdev {
+    _r: Registration<Box<DriverData>>,
+}
+
+#[vtable]
+impl EtherOperations for Box<DriverData> {
+    fn get_ts_info(dev: Device<Box<DriverData>>, mut info: EthtoolTsInfo) -> Result {
+        EthtoolTsInfo::ethtool_op_get_ts_info(&dev, &mut info)
+    }
+}
+
+impl kernel::Module for DummyNetdev {
+    fn init(_module: &'static ThisModule) -> Result<Self> {
+        let data = Box::try_new(DriverData {})?;
+        let mut r = Registration::<Box<DriverData>>::try_new_ether(1, 1, data)?;
+        r.set_ether_operations::<Box<DriverData>>()?;
+
+        let netdev = r.dev_get();
+        netdev.set_name(c_str!("dummy%d"))?;
+
+        netdev.set_flags(netdev.get_flags() | flags::IFF_NOARP & !flags::IFF_MULTICAST);
+        netdev.set_priv_flags(
+            netdev.get_priv_flags() | priv_flags::IFF_LIVE_ADDR_CHANGE | priv_flags::IFF_NO_QUEUE,
+        );
+        netdev.set_random_eth_hw_addr();
+        netdev.set_min_mtu(0);
+        netdev.set_max_mtu(0);
+
+        r.register()?;
+
+        // TODO: Replaces pr_info with the wrapper of netdev_info().
+        pr_info!("Hello Rust dummy netdev!");
+        Ok(DummyNetdev { _r: r })
+    }
+}
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 78175231c969..1404967e908e 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -277,7 +277,7 @@ $(obj)/%.lst: $(src)/%.c FORCE
 # Compile Rust sources (.rs)
 # ---------------------------------------------------------------------------
 
-rust_allowed_features := new_uninit
+rust_allowed_features := allocator_api,new_uninit
 
 rust_common_cmd = \
 	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
-- 
2.34.1