From 7ee240a384854068b898e08e7e3366226047bacf Mon Sep 17 00:00:00 2001
From: Wedson Almeida Filho <wedsonaf@google.com>
Date: Tue, 26 Apr 2022 14:32:57 +0000
Subject: [PATCH] samples/rust: add echo server sample
This example uses Rust async for the server and a workqueue-based
executor to run async tasks.
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
---
samples/rust/Kconfig | 10 ++++++
samples/rust/Makefile | 1 +
samples/rust/rust_echo_server.rs | 60 ++++++++++++++++++++++++++++++++
3 files changed, 71 insertions(+)
create mode 100644 samples/rust/rust_echo_server.rs
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index 4f90f8d6935188..fe923ef2ab93ba 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -130,6 +130,16 @@ config SAMPLE_RUST_NETFILTER
If unsure, say N.
+config SAMPLE_RUST_ECHO_SERVER
+ tristate "Echo server module"
+ help
+ This option builds the Rust echo server module sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_echo_server.
+
+ If unsure, say N.
+
config SAMPLE_RUST_HOSTPROGS
bool "Host programs"
help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index fb5a205ebb8cf8..636cf1e73d23cc 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -12,5 +12,6 @@ obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE_C) += rust_semaphore_c.o
obj-$(CONFIG_SAMPLE_RUST_RANDOM) += rust_random.o
obj-$(CONFIG_SAMPLE_RUST_PLATFORM) += rust_platform.o
obj-$(CONFIG_SAMPLE_RUST_NETFILTER) += rust_netfilter.o
+obj-$(CONFIG_SAMPLE_RUST_ECHO_SERVER) += rust_echo_server.o
subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs
diff --git a/samples/rust/rust_echo_server.rs b/samples/rust/rust_echo_server.rs
new file mode 100644
index 00000000000000..5fc802f4dc33c2
--- /dev/null
+++ b/samples/rust/rust_echo_server.rs
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust echo server sample.
+
+use kernel::{
+ kasync::executor::{workqueue::Executor as WqExecutor, AutoStopHandle, Executor},
+ kasync::net::{TcpListener, TcpStream},
+ net::{self, Ipv4Addr, SocketAddr, SocketAddrV4},
+ prelude::*,
+ spawn_task,
+ sync::{Ref, RefBorrow},
+};
+
+async fn echo_server(stream: TcpStream) -> Result {
+ let mut buf = [0u8; 1024];
+ loop {
+ let n = stream.read(&mut buf).await?;
+ if n == 0 {
+ return Ok(());
+ }
+ stream.write_all(&buf[..n]).await?;
+ }
+}
+
+async fn accept_loop(listener: TcpListener, executor: Ref<impl Executor>) {
+ loop {
+ if let Ok(stream) = listener.accept().await {
+ let _ = spawn_task!(executor.as_ref_borrow(), echo_server(stream));
+ }
+ }
+}
+
+fn start_listener(ex: RefBorrow<'_, impl Executor + Send + Sync + 'static>) -> Result {
+ let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::ANY, 8080));
+ let listener = TcpListener::try_new(net::init_ns(), &addr)?;
+ spawn_task!(ex, accept_loop(listener, ex.into()))?;
+ Ok(())
+}
+
+struct RustEchoServer {
+ _handle: AutoStopHandle<dyn Executor>,
+}
+
+impl kernel::Module for RustEchoServer {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ let handle = WqExecutor::try_new(kernel::workqueue::system())?;
+ start_listener(handle.executor())?;
+ Ok(Self {
+ _handle: handle.into(),
+ })
+ }
+}
+
+module! {
+ type: RustEchoServer,
+ name: b"rust_echo_server",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust tcp echo sample",
+ license: b"GPL v2",
+}