RouteGetRequest: specify NLM_F_DUMP only when no destination address specified

We can have the behaviour of `ip route get` now.

Co-Developed-By: Nevo Hed <nhed@users.noreply.github.com>

Author: hack3ric

src/route/get.rs

@@ -8,7 +8,8 @@ use futures::{
 
 use netlink_packet_core::{NetlinkMessage, NLM_F_DUMP, NLM_F_REQUEST};
 use netlink_packet_route::{
-    route::RouteMessage, AddressFamily, RouteNetlinkMessage,
+    route::{RouteAttribute, RouteMessage},
+    AddressFamily, RouteNetlinkMessage,
 };
 
 use crate::{try_rtnl, Error, Handle};
@@ -51,9 +52,18 @@ impl RouteGetRequest {
             message,
         } = self;
 
+        let has_dest = message
+            .attributes
+            .iter()
+            .any(|attr| matches!(attr, RouteAttribute::Destination(_)));
+
         let mut req =
             NetlinkMessage::from(RouteNetlinkMessage::GetRoute(message));
-        req.header.flags = NLM_F_REQUEST | NLM_F_DUMP;
+        req.header.flags = NLM_F_REQUEST;
+
+        if !has_dest {
+            req.header.flags |= NLM_F_DUMP;
+        }
 
         match handle.request(req) {
             Ok(response) => Either::Left(response.map(move |msg| {