simplify netlink operations

src/routing.rs

@@ -2,6 +2,10 @@ use anyhow::Result;
 use libc::if_nametoindex;
 use log::{debug, info};
 use netlink_packet_route::route::RouteAddress;
+use netlink_packet_route::{
+    AddressFamily, RouteNetlinkMessage,
+    route::{RouteAttribute, RouteHeader, RouteMessage, RouteProtocol, RouteScope, RouteType},
+};
 use std::ffi::CString;
 use std::net::Ipv4Addr;
 
@@ -123,36 +127,16 @@ impl RouteManager {
         use netlink_packet_core::{
             NLM_F_ACK, NLM_F_CREATE, NLM_F_REQUEST, NetlinkHeader, NetlinkMessage, NetlinkPayload,
         };
-        use netlink_packet_route::{
-            AddressFamily, RouteNetlinkMessage,
-            route::RouteProtocol,
-            route::RouteScope,
-            route::{RouteAttribute, RouteHeader, RouteMessage, RouteType},
-        };
         use netlink_sys::{Socket, SocketAddr, protocols::NETLINK_ROUTE};
 
         let mut socket = Socket::new(NETLINK_ROUTE)?;
         let _port_number = socket.bind_auto()?.port_number();
         socket.connect(&SocketAddr::new(0, 0))?;
-        let route_msg_hdr = RouteHeader {
-            address_family: AddressFamily::Inet,
-            table: MAIN_TABLE_ID,
-            destination_prefix_length: 0, // Default route
-            protocol: RouteProtocol::Boot,
-            scope: RouteScope::Universe,
-            kind: RouteType::Unicast,
-            ..Default::default()
-        };
 
-        let mut route_msg = RouteMessage::default();
-        route_msg.header = route_msg_hdr;
-        route_msg.attributes = vec![
-            RouteAttribute::Gateway(RouteAddress::Inet(route_info.gateway)),
-            RouteAttribute::Oif(index),
-            RouteAttribute::Priority(route_info.metric),
-        ];
+        let route_msg = create_route_message(route_info.gateway, index, route_info.metric);
+
         let mut nl_hdr = NetlinkHeader::default();
-        nl_hdr.flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK; // Remove NLM_F_EXCL to allow updates
+        nl_hdr.flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
 
         let mut msg = NetlinkMessage::new(
             nl_hdr,
@@ -161,11 +145,8 @@ impl RouteManager {
 
         msg.finalize();
         let mut buf = vec![0; 1024 * 8];
-
         msg.serialize(&mut buf[..msg.buffer_len()]);
 
-        // Debug: Log the netlink message being sent
-        debug!("Netlink message being sent: {:?}", &buf[..msg.buffer_len()]);
         debug!(
             "Route addition attempt: gateway={}, interface={}, metric={}, interface_index={}",
             route_info.gateway, route_info.interface, route_info.metric, index
@@ -198,35 +179,20 @@ impl RouteManager {
                                 route_info.metric
                             );
                         } else {
-                            let error_str = match error_code {
-                                -1 => "EPERM - Operation not permitted (need root privileges)",
-                                -2 => "ENOENT - No such file or directory",
-                                -13 => "EACCES - Permission denied",
-                                -22 => "EINVAL - Invalid argument",
-                                _ => "Unknown error",
-                            };
-                            return Err(anyhow::anyhow!(
-                                "Failed to add route: {} (code: {}): {:?}",
-                                error_str,
-                                error_code,
-                                error_msg
-                            ));
+                            return handle_netlink_error(error_code);
                         }
                     }
                     debug!("Route added successfully");
                 }
+                Ok(())
             }
-            Err(e) => {
-                return Err(anyhow::anyhow!(
+            Err(e) => Err(anyhow::anyhow!(
                 "Failed to deserialize netlink message: {}",
                 e
-                ));
+            )),
         }
     }
 
-        Ok(())
-    }
-
     fn delete_default_route_internal(
         &self,
         gateway: Ipv4Addr,
@@ -242,35 +208,13 @@ impl RouteManager {
         use netlink_packet_core::{
             NLM_F_ACK, NLM_F_REQUEST, NetlinkHeader, NetlinkMessage, NetlinkPayload,
         };
-        use netlink_packet_route::{
-            AddressFamily, RouteNetlinkMessage,
-            route::RouteProtocol,
-            route::RouteScope,
-            route::{RouteAttribute, RouteHeader, RouteMessage, RouteType},
-        };
         use netlink_sys::{Socket, SocketAddr, protocols::NETLINK_ROUTE};
 
         let mut socket = Socket::new(NETLINK_ROUTE)?;
         let _port_number = socket.bind_auto()?.port_number();
         socket.connect(&SocketAddr::new(0, 0))?;
 
-        let route_msg_hdr = RouteHeader {
-            address_family: AddressFamily::Inet,
-            table: MAIN_TABLE_ID,
-            destination_prefix_length: 0, // Default route
-            protocol: RouteProtocol::Boot,
-            scope: RouteScope::Universe,
-            kind: RouteType::Unicast,
-            ..Default::default()
-        };
-
-        let mut route_msg = RouteMessage::default();
-        route_msg.header = route_msg_hdr;
-        route_msg.attributes = vec![
-            RouteAttribute::Gateway(RouteAddress::Inet(gateway)),
-            RouteAttribute::Oif(index),
-            RouteAttribute::Priority(metric),
-        ];
+        let route_msg = create_route_message(gateway, index, metric);
 
         let mut nl_hdr = NetlinkHeader::default();
         nl_hdr.flags = NLM_F_REQUEST | NLM_F_ACK;
@@ -282,14 +226,8 @@ impl RouteManager {
 
         msg.finalize();
         let mut buf = vec![0; 1024 * 8];
-
         msg.serialize(&mut buf[..msg.buffer_len()]);
 
-        // Debug: Log the netlink message being sent
-        debug!(
-            "Netlink delete message being sent: {:?}",
-            &buf[..msg.buffer_len()]
-        );
         debug!(
             "Route deletion attempt: gateway={}, interface={}, metric={}, interface_index={}",
             gateway, interface, metric, index
@@ -315,17 +253,14 @@ impl RouteManager {
                     }
                     debug!("Route deleted successfully");
                 }
+                Ok(())
             }
-            Err(e) => {
-                return Err(anyhow::anyhow!(
+            Err(e) => Err(anyhow::anyhow!(
                 "Failed to deserialize netlink message: {}",
                 e
-                ));
+            )),
         }
     }
-
-        Ok(())
-    }
 }
 
 fn get_interface_index(iface_name: &str) -> Result<u32> {
@@ -338,3 +273,44 @@ fn get_interface_index(iface_name: &str) -> Result<u32> {
         Ok(index)
     }
 }
+
+fn create_route_header() -> RouteHeader {
+    RouteHeader {
+        address_family: AddressFamily::Inet,
+        table: MAIN_TABLE_ID,
+        destination_prefix_length: 0, // Default route
+        protocol: RouteProtocol::Boot,
+        scope: RouteScope::Universe,
+        kind: RouteType::Unicast,
+        ..Default::default()
+    }
+}
+
+fn handle_netlink_error(error_code: i32) -> Result<()> {
+    if error_code == -17 {
+        // EEXIST - Route already exists, treat as success
+        return Ok(());
+    }
+
+    let error_str = match error_code {
+        -1 => "EPERM - Operation not permitted (need root privileges)",
+        -2 => "ENOENT - No such file or directory",
+        -13 => "EACCES - Permission denied",
+        -22 => "EINVAL - Invalid argument",
+        _ => "Unknown error",
+    };
+    Err(anyhow::anyhow!("Netlink operation failed: {}", error_str))
+}
+
+fn create_route_message(gateway: Ipv4Addr, interface_index: u32, metric: u32) -> RouteMessage {
+    let route_msg_hdr = create_route_header();
+
+    let mut route_msg = RouteMessage::default();
+    route_msg.header = route_msg_hdr;
+    route_msg.attributes = vec![
+        RouteAttribute::Gateway(RouteAddress::Inet(gateway)),
+        RouteAttribute::Oif(interface_index),
+        RouteAttribute::Priority(metric),
+    ];
+    route_msg
+}