listen part

src/main.rs

@@ -0,0 +1,79 @@
+use anyhow::{anyhow, Result};
+use env_logger;
+use futures::stream::StreamExt;
+use log::{debug, error, info, log_enabled, Level};
+use netlink_packet_core::NetlinkPayload;
+use netlink_packet_route::RouteNetlinkMessage as RtnlMessage;
+use netlink_sys::{AsyncSocket, SocketAddr};
+use rtnetlink::new_connection;
+
+const RTNLGRP_LINK: u32 = 1;
+const RTNLGRP_IPV4_IFADDR: u32 = 5;
+
+const fn nl_mgrp(group: u32) -> u32 {
+    if group > 31 {
+        panic!("use netlink_sys::Socket::add_membership() for this group");
+    }
+    if group == 0 {
+        0
+    } else {
+        1 << (group - 1)
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    env_logger::init();
+    let (mut conn, mut _handle, mut messages) = new_connection().map_err(|e| anyhow!(e))?;
+    let groups = nl_mgrp(RTNLGRP_LINK) | nl_mgrp(RTNLGRP_IPV4_IFADDR);
+
+    let addr = SocketAddr::new(0, groups);
+
+    if let Err(e) = conn.socket_mut().socket_mut().bind(&addr) {
+        error!("Failed to bind to socket: {:?}", &e);
+        return Err(anyhow!(e));
+    }
+
+    tokio::spawn(conn);
+    info!("Listening for IPv4 address changes and interface connect/disconnect events...");
+
+    while let Some((message, _)) = messages.next().await {
+        match message.payload {
+            NetlinkPayload::InnerMessage(RtnlMessage::NewAddress(msg)) => {
+                if log_enabled!(Level::Debug) {
+                    debug!("New IPv4 address message: {:?}", msg);
+                } else {
+                    info!("New IPv4 address");
+                }
+            }
+            NetlinkPayload::InnerMessage(RtnlMessage::DelAddress(msg)) => {
+                if log_enabled!(Level::Debug) {
+                    debug!("Deleted IPv4 address message: {:?}", msg);
+                } else {
+                    info!("Deleted IPv4 address");
+                }
+            }
+            NetlinkPayload::InnerMessage(RtnlMessage::NewLink(link)) => {
+                if log_enabled!(Level::Debug) {
+                    debug!("New link message (interface connected): {:?}", link);
+                } else {
+                    info!("New link (interface connected)");
+                }
+            }
+            NetlinkPayload::InnerMessage(RtnlMessage::DelLink(link)) => {
+                if log_enabled!(Level::Debug) {
+                    debug!("Deleted link message (interface disconnected): {:?}", link);
+                } else {
+                    info!("Deleted link (interface disconnected)");
+                }
+            }
+            _ => {
+                if log_enabled!(Level::Debug) {
+                    debug!("Unhandled message payload: {:?}", message.payload);
+                }
+            }
+        }
+    }
+
+    Ok(())
+}