Merge pull request #3702 from BartMassey-upstream/std-example-cosmetics

std example cosmetics

examples/std/README.md

@@ -1,16 +1,12 @@
 
 ## Running the `embassy-net` examples
 
-First, create the tap0 interface. You only need to do this once.
+First, create the tap99 interface. (The number was chosen to
+hopefully not collide with anything.) You only need to do
+this once.
 
 ```sh
-sudo ip tuntap add name tap0 mode tap user $USER
+sudo sh tap.sh
-sudo ip link set tap0 up
-sudo ip addr add 192.168.69.100/24 dev tap0
-sudo ip -6 addr add fe80::100/64 dev tap0
-sudo ip -6 addr add fdaa::100/64 dev tap0
-sudo ip -6 route add fe80::/64 dev tap0
-sudo ip -6 route add fdaa::/64 dev tap0
 ```
 
 Second, have something listening there. For example `nc -lp 8000`
@@ -19,5 +15,5 @@ Then run the example located in the `examples` folder:
 
 ```sh
 cd $EMBASSY_ROOT/examples/std/
-cargo run --bin net -- --static-ip
+sudo cargo run --bin net -- --tap tap99 --static-ip
 ```

examples/std/src/bin/net.rs

@@ -1,3 +1,5 @@
+use core::fmt::Write as _;
+
 use clap::Parser;
 use embassy_executor::{Executor, Spawner};
 use embassy_net::tcp::TcpSocket;
@@ -71,8 +73,10 @@ async fn main_task(spawner: Spawner) {
         return;
     }
     info!("connected!");
-    loop {
+    for i in 0.. {
-        let r = socket.write_all(b"Hello!\n").await;
+        let mut buf = heapless::String::<100>::new();
+        write!(buf, "Hello! ({})\r\n", i).unwrap();
+        let r = socket.write_all(buf.as_bytes()).await;
         if let Err(e) = r {
             warn!("write error: {:?}", e);
             return;

examples/std/tap.sh

@@ -0,0 +1,7 @@
+ip tuntap add name tap99 mode tap user $USER
+ip link set tap99 up
+ip addr add 192.168.69.100/24 dev tap99
+ip -6 addr add fe80::100/64 dev tap99
+ip -6 addr add fdaa::100/64 dev tap99
+ip -6 route add fe80::/64 dev tap99
+ip -6 route add fdaa::/64 dev tap99