fix(host_metrics source): use recv_from_full in fetch_netlink_inet_headers

Author: mushrowan

changelog.d/22487_tcp_netlink_parsing.fix.md

@@ -0,0 +1,3 @@
+fixed tcp metrics collection in `host_metrics` source failing with "Could not parse netlink response: invalid netlink buffer" errors on Linux systems.
+
+authors: mushrowan

src/sources/host_metrics/tcp.rs

@@ -241,13 +241,20 @@ async fn fetch_netlink_inet_headers(addr_family: u8) -> Result<Vec<InetResponseH
         .await
         .context(NetlinkSendSnafu)?;
 
-    let mut receive_buffer = vec![0; 4096];
     let mut inet_resp_hdrs = Vec::with_capacity(32); // Pre-allocate with an estimate
 
-    while let Ok(()) = socket.recv(&mut &mut receive_buffer[..]).await {
-        let done = parse_netlink_messages(&receive_buffer, &mut inet_resp_hdrs)?;
-        if done {
-            break;
+    loop {
+        match socket.recv_from_full().await {
+            Ok((receive_buffer, _addr)) => {
+                if receive_buffer.is_empty() {
+                    break;
+                }
+                let done = parse_netlink_messages(&receive_buffer, &mut inet_resp_hdrs)?;
+                if done {
+                    break;
+                }
+            }
+            Err(_) => break,
         }
     }