Introduce LinkMessageBuilder

**API BREAK**

To remove the duplicate error of `LinkAddRequest` and `LinkSetRequest`,
this patch introduce `LinkMessageBuilder` to generate `LinkMessage` for
link handlers to use.

The `impl LinkMessageBuilder<T>` holds the common functions available for all
interface types.
The `impl LinkMessageBuilder<LinkVlan>` holds VLAN specific functions.

The LinkMessageBuilder is designed for advanced user, wrapper functions
are created for common use cases. For example, to create a VLAN
interface:

```rus
let (connection, handle, _) = new_connection().unwrap();
tokio::spawn(connection);

handle
    .link()
    .add(
        LinkVlan::new("vlan100", 10, 100)
            .up()
            .build()
    )
    .execute()
    .await
    .map_err(|e| format!("{e}"))
```

These patches included these new structures to generate matching
LinkMessageBuilder:

 * `LinkUnspec` (for matching existing interface)
 * `LinkDummy`
 * `LinkVeth`
 * `LinkVlan`
 * `LinkVxlan`
 * `LinkMacVlan`
 * `LinkMacVtap`
 * `LinkWireguard`
 * `LinkBondPort`

Special note:

 * Due to confliction, the previous VxLAN `link()` function changed to
   `dev()`. The `link()` is the share function for all interface types. The
   API is matching with `ip link` command line option for vxlan.
   Please check `examples/create_vxlan.rs` for usage.

 * The `LinkHandler::set_bond_port()` changed to
   `LinkHandler::set_port()`, please check `examples/set_bond_port.rs`
   for usage.

 * The `message_mut()` function is removed from `LinkSetRequest` and
   `LinkAddRequest`, user should modify the LinkMessage before sent to
   handler.

Signed-off-by: Gris Ge <[email protected]>

examples/create_bond.rs

@@ -1,17 +1,15 @@
 // SPDX-License-Identifier: MIT
 
-use netlink_packet_route::link::BondMode;
-use rtnetlink::new_connection;
 use std::net::{Ipv4Addr, Ipv6Addr};
 
+use rtnetlink::{new_connection, packet_route::link::BondMode, LinkBond};
+
 #[tokio::main]
 async fn main() -> Result<(), String> {
     let (connection, handle, _) = new_connection().unwrap();
     tokio::spawn(connection);
-    handle
-        .link()
-        .add()
-        .bond("my-bond".into())
+
+    let message = LinkBond::new("my-bond")
         .mode(BondMode::ActiveBackup)
         .miimon(100)
         .updelay(100)
@@ -26,6 +24,11 @@ async fn main() -> Result<(), String> {
             Ipv6Addr::new(0xfd02, 0, 0, 0, 0, 0, 0, 2),
         ])
         .up()
+        .build();
+
+    handle
+        .link()
+        .add(message)
         .execute()
         .await
         .map_err(|e| format!("{e}"))

examples/create_bridge.rs

@@ -1,15 +1,15 @@
 // SPDX-License-Identifier: MIT
 
-use rtnetlink::new_connection;
+use rtnetlink::{new_connection, LinkBridge};
 
 #[tokio::main]
 async fn main() -> Result<(), String> {
     let (connection, handle, _) = new_connection().unwrap();
     tokio::spawn(connection);
+
     handle
         .link()
-        .add()
-        .bridge("my-bridge-1".into())
+        .add(LinkBridge::new("my-bridge").build())
         .execute()
         .await
         .map_err(|e| format!("{e}"))

examples/create_dummy.rs

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+
+use rtnetlink::{new_connection, LinkDummy};
+
+#[tokio::main]
+async fn main() -> Result<(), String> {
+    let (connection, handle, _) = new_connection().unwrap();
+    tokio::spawn(connection);
+
+    handle
+        .link()
+        .add(LinkDummy::new("dummy0").build())
+        .execute()
+        .await
+        .map_err(|e| format!("{e}"))
+}

examples/create_macvlan.rs

@@ -1,11 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-use futures::stream::TryStreamExt;
-use macaddr::MacAddr;
-use rtnetlink::{new_connection, Error, Handle};
 use std::{env, str::FromStr};
 
-use netlink_packet_route::link::{LinkAttribute, MacVlanMode};
+use futures::stream::TryStreamExt;
+use macaddr::MacAddr;
+use rtnetlink::{
+    new_connection, packet_route::link::MacVlanMode, Error, Handle, LinkMacVlan,
+};
 
 #[tokio::main]
 async fn main() -> Result<(), String> {
@@ -37,19 +38,20 @@ async fn create_macvlan(
     link_name: String,
     mac_address: Option<Vec<u8>>,
 ) -> Result<(), Error> {
-    let mut links = handle.link().get().match_name(link_name.clone()).execute();
-    if let Some(link) = links.try_next().await? {
-        let mut request = handle.link().add().macvlan(
-            "test_macvlan".into(),
-            link.header.index,
+    let mut parent_links =
+        handle.link().get().match_name(link_name.clone()).execute();
+    if let Some(parent) = parent_links.try_next().await? {
+        let mut builder = LinkMacVlan::new(
+            "my-macvlan",
+            parent.header.index,
             MacVlanMode::Bridge,
         );
         if let Some(mac) = mac_address {
-            request
-                .message_mut()
-                .attributes
-                .push(LinkAttribute::Address(mac));
+            builder = builder.address(mac);
         }
+        let message = builder.build();
+        let request = handle.link().add(message);
+
         request.execute().await?
     } else {
         println!("no link {link_name} found");

examples/create_macvtap.rs

@@ -1,10 +1,12 @@
 // SPDX-License-Identifier: MIT
 
-use futures::stream::TryStreamExt;
-use netlink_packet_route::link::MacVtapMode;
-use rtnetlink::{new_connection, Error, Handle};
 use std::env;
 
+use futures::stream::TryStreamExt;
+use rtnetlink::{
+    new_connection, packet_route::link::MacVtapMode, Error, Handle, LinkMacVtap,
+};
+
 #[tokio::main]
 async fn main() -> Result<(), String> {
     let args: Vec<String> = env::args().collect();
@@ -24,18 +26,22 @@ async fn main() -> Result<(), String> {
 
 async fn create_macvtap(
     handle: Handle,
-    veth_name: String,
+    link_name: String,
 ) -> Result<(), Error> {
-    let mut links = handle.link().get().match_name(veth_name.clone()).execute();
-    if let Some(link) = links.try_next().await? {
-        let request = handle.link().add().macvtap(
-            "test_macvtap".into(),
-            link.header.index,
+    let mut parent_links =
+        handle.link().get().match_name(link_name.clone()).execute();
+    if let Some(parent) = parent_links.try_next().await? {
+        let message = LinkMacVtap::new(
+            "test_macvtap",
+            parent.header.index,
             MacVtapMode::Bridge,
-        );
+        )
+        .build();
+
+        let request = handle.link().add(message);
         request.execute().await?
     } else {
-        println!("no link link {veth_name} found");
+        println!("no link link {link_name} found");
     }
     Ok(())
 }

examples/create_veth.rs

@@ -1,15 +1,14 @@
 // SPDX-License-Identifier: MIT
 
-use rtnetlink::new_connection;
-
+use rtnetlink::{new_connection, LinkVeth};
 #[tokio::main]
 async fn main() -> Result<(), String> {
     let (connection, handle, _) = new_connection().unwrap();
     tokio::spawn(connection);
+
     handle
         .link()
-        .add()
-        .veth("veth-rs-1".into(), "veth-rs-2".into())
+        .add(LinkVeth::new("veth1", "veth1-peer").build())
         .execute()
         .await
         .map_err(|e| format!("{e}"))

examples/create_vlan.rs

@@ -2,7 +2,7 @@
 
 use std::{env, error::Error as StdError, str::FromStr};
 
-use rtnetlink::{new_connection, QosMapping};
+use rtnetlink::{new_connection, LinkVlan, QosMapping};
 
 fn parse_mapping(parameter: &str) -> Result<QosMapping, Box<dyn StdError>> {
     let (from, to) = parameter
@@ -109,10 +109,14 @@ async fn main() -> Result<(), String> {
     let (connection, handle, _) = new_connection().unwrap();
     tokio::spawn(connection);
 
+    let message = LinkVlan::new(&name, base, id)
+        .up()
+        .qos(ingress, egress)
+        .build();
+
     handle
         .link()
-        .add()
-        .vlan_with_qos(name, base, id, ingress, egress)
+        .add(message)
         .execute()
         .await
         .map_err(|err| format!("Netlink request failed: {err}"))

examples/create_vrf.rs

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+
+use rtnetlink::{new_connection, LinkVrf};
+
+#[tokio::main]
+async fn main() -> Result<(), String> {
+    let (connection, handle, _) = new_connection().unwrap();
+    tokio::spawn(connection);
+
+    handle
+        .link()
+        .add(LinkVrf::new("my-vrf", 101).build())
+        .execute()
+        .await
+        .map_err(|e| format!("{e}"))
+}

examples/create_vxlan.rs

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 
 use futures::stream::TryStreamExt;
-use rtnetlink::{new_connection, Error, Handle};
+use rtnetlink::{new_connection, Error, Handle, LinkVxlan};
 use std::env;
 
 #[tokio::main]
@@ -24,15 +24,13 @@ async fn main() -> Result<(), String> {
 async fn create_vxlan(handle: Handle, name: String) -> Result<(), Error> {
     let mut links = handle.link().get().match_name(name.clone()).execute();
     if let Some(link) = links.try_next().await? {
-        handle
-            .link()
-            .add()
-            .vxlan("vxlan0".into(), 10u32)
-            .link(link.header.index)
-            .port(4789)
+        let message = LinkVxlan::new("vxlan0", 10)
+            .dev(link.header.index)
             .up()
-            .execute()
-            .await?
+            .port(4789)
+            .build();
+
+        handle.link().add(message).execute().await?
     } else {
         println!("no link link {name} found");
     }

examples/create_wireguard.rs

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+
+use rtnetlink::{new_connection, LinkWireguard};
+
+#[tokio::main]
+async fn main() -> Result<(), String> {
+    let (connection, handle, _) = new_connection().unwrap();
+    tokio::spawn(connection);
+
+    handle
+        .link()
+        .add(LinkWireguard::new("my-wg").build())
+        .execute()
+        .await
+        .map_err(|e| format!("{e}"))
+}

examples/create_xfrm.rs

@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: MIT
+
+use futures::stream::TryStreamExt;
+use rtnetlink::{new_connection, Error, Handle, LinkXfrm};
+
+#[tokio::main]
+async fn main() -> Result<(), String> {
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() != 2 {
+        usage();
+        return Ok(());
+    }
+    let link_name = &args[1];
+
+    let (connection, handle, _) = new_connection().unwrap();
+    tokio::spawn(connection);
+
+    create_xfrm(handle, link_name.to_string())
+        .await
+        .map_err(|e| format!("{e}"))
+}
+
+async fn create_xfrm(handle: Handle, link_name: String) -> Result<(), Error> {
+    let mut parent_links =
+        handle.link().get().match_name(link_name.clone()).execute();
+    if let Some(parent) = parent_links.try_next().await? {
+        let request = handle
+            .link()
+            .add(LinkXfrm::new("my-xfrm", parent.header.index, 0x08).build());
+
+        request.execute().await?
+    } else {
+        println!("no link {link_name} found");
+    }
+    Ok(())
+}
+
+fn usage() {
+    eprintln!(
+        "usage:
+    cargo run --example create_xfrm -- <link name>
+
+Note that you need to run this program as root. Instead of running cargo as
+root, build the example normally:
+
+    cargo build --example create_xfrm
+
+Then find the binary in the target directory:
+
+    cd target/debug/examples ; sudo ./create_xfrm <link_name>"
+    );
+}

examples/get_bond_port_settings.rs

@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: MIT
 
 use futures::stream::TryStreamExt;
-use rtnetlink::{new_connection, Error, Handle};
+use rtnetlink::{
+    new_connection, packet_route::link::LinkAttribute, Error, Handle,
+};
 use std::env;
 
 #[tokio::main]
@@ -35,7 +37,11 @@ async fn dump_bond_port_settings(
         let mut link_messgage =
             handle.link().get().match_name(linkname).execute();
         while let Some(msg) = link_messgage.try_next().await? {
-            println!("{msg:?}");
+            for nla in msg.attributes {
+                if let LinkAttribute::LinkInfo(i) = &nla {
+                    println!("{:?}", i);
+                }
+            }
         }
         Ok(())
     } else {