Add wireguard set example

Cargo.toml

@@ -13,6 +13,7 @@ description = "Wireguard generic netlink packet definitions"
 [dependencies]
 anyhow = "1.0.42"
 byteorder = "1.4.3"
+getrandom = "0.2.10"
 libc = "0.2.98"
 log = "0.4.14"
 netlink-packet-generic = { version = "0.3.3" }

examples/set_wireguard.rs

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: MIT
+
+use futures::StreamExt;
+use genetlink::new_connection;
+use getrandom;
+use netlink_packet_core::{
+    NetlinkMessage, NetlinkPayload, NLM_F_ACK, NLM_F_REQUEST,
+};
+use netlink_packet_generic::GenlMessage;
+use netlink_packet_wireguard::constants::*;
+use netlink_packet_wireguard::{nlas::WgDeviceAttrs, Wireguard, WireguardCmd};
+use std::env::args;
+
+#[tokio::main]
+async fn main() {
+    env_logger::init();
+
+    let argv: Vec<String> = args().collect();
+    if argv.len() < 2 {
+        eprintln!("Usage: set_wireguard <ifname>");
+        return;
+    }
+
+    // The wireguard interface need to exist before executing this code.
+    // This can be done with `ip link <name> type wireguard` command.
+    let name = argv[1].clone();
+    let priv_key = generate_priv_key();
+
+    let (connection, mut handle, _) = new_connection().unwrap();
+    let _ = tokio::spawn(connection);
+
+    let nlas = vec![
+        WgDeviceAttrs::IfName(name),
+        WgDeviceAttrs::PrivateKey(priv_key),
+        WgDeviceAttrs::ListenPort(51820),
+    ];
+
+    let genlmsg: GenlMessage<Wireguard> =
+        GenlMessage::from_payload(Wireguard {
+            cmd: WireguardCmd::SetDevice,
+            nlas,
+        });
+    let mut nlmsg = NetlinkMessage::from(genlmsg);
+    nlmsg.header.flags = NLM_F_REQUEST | NLM_F_ACK;
+
+    let mut res = handle.request(nlmsg).await.unwrap();
+
+    if let Some(result) = res.next().await {
+        let rx_packet = result.unwrap();
+        match rx_packet.payload {
+            NetlinkPayload::Error(e) => {
+                eprintln!("Error: {:?}", e.to_io());
+            }
+            _ => (),
+        }
+    }
+}
+
+fn generate_priv_key() -> [u8; WG_KEY_LEN] {
+    let mut key = [0u8; WG_KEY_LEN];
+    getrandom::getrandom(&mut key).unwrap();
+    // modify random bytes using algorithm described
+    // at https://cr.yp.to/ecdh.html.
+    key[0] = key[0] & 248;
+    key[31] = key[31] & 127;
+    key[31] = key[31] | 64;
+    key
+}