Make the world flat again; remove utils/ subdirectory (#5752)

automerge

netutil/src/ip_echo_server.rs

@@ -0,0 +1,44 @@
+use log::*;
+use std::net::SocketAddr;
+use tokio;
+use tokio::net::TcpListener;
+use tokio::prelude::{Future, Stream};
+use tokio::runtime::Runtime;
+
+pub type IpEchoServer = Runtime;
+
+/// Starts a simple TCP server on the given port that echos the IP address of any peer that
+/// connects.  Used by |get_public_ip_addr|
+pub fn ip_echo_server(port: u16) -> IpEchoServer {
+    let bind_addr = SocketAddr::from(([0, 0, 0, 0], port));
+    let tcp = TcpListener::bind(&bind_addr)
+        .unwrap_or_else(|err| panic!("Unable to bind to {}: {}", bind_addr, err));
+    info!("bound to {:?}", bind_addr);
+
+    let server = tcp
+        .incoming()
+        .map_err(|err| warn!("accept failed: {:?}", err))
+        .for_each(move |socket| {
+            let ip = socket
+                .peer_addr()
+                .and_then(|peer_addr| {
+                    bincode::serialize(&peer_addr.ip()).map_err(|err| {
+                        std::io::Error::new(
+                            std::io::ErrorKind::Other,
+                            format!("Failed to serialize: {:?}", err),
+                        )
+                    })
+                })
+                .unwrap_or_else(|_| vec![]);
+
+            let write_future = tokio::io::write_all(socket, ip)
+                .map_err(|err| warn!("write error: {:?}", err))
+                .map(|_| ());
+
+            tokio::spawn(write_future)
+        });
+
+    let mut rt = Runtime::new().expect("Failed to create Runtime");
+    rt.spawn(server);
+    rt
+}