Add DNS support

src/main.rs

@@ -1,5 +1,5 @@
 use std::io::Write;
-use std::net::ToSocketAddrs;
+use std::net::{AddrParseError, IpAddr, ToSocketAddrs};
 use std::process;
 
 use log::debug;
@@ -26,6 +26,9 @@ struct ConfigOpts {
     location: String,
     username: String,
     token: String,
+
+    #[clap(short, long)]
+    no_dns: bool,
 }
 
 #[derive(Clap, Debug)]
@@ -78,6 +81,9 @@ struct WireguardConfigData {
     public_key: String,
     address: String,
     endpoint: String,
+
+    #[serde(rename = "DNS")]
+    dns: String,
 }
 
 #[derive(Debug)]
@@ -86,6 +92,15 @@ struct WireguardKeyPair {
     private_key: String,
 }
 
+impl WireguardConfigData {
+    fn dns(&self) -> Result<Vec<IpAddr>, AddrParseError> {
+        self.dns
+            .split(',')
+            .map(|s: &str| -> Result<IpAddr, AddrParseError> { s.trim().parse() })
+            .collect()
+    }
+}
+
 fn main() -> Result<(), anyhow::Error> {
     env_logger::init();
     let opts = Opts::parse();
@@ -135,11 +150,12 @@ fn get_config(_opts: &Opts, config_opts: &ConfigOpts) -> Result<(), anyhow::Erro
         .into_json()?;
     debug!("config = {:?}", &config);
 
-    write_config(&mut std::io::stdout().lock(), &config, &keys)
+    write_config(&mut std::io::stdout().lock(), &config_opts, &config, &keys)
 }
 
 fn write_config(
     output: &mut dyn Write,
+    config_opts: &ConfigOpts,
     config: &WireguardConfig,
     keys: &WireguardKeyPair,
 ) -> Result<(), anyhow::Error> {
@@ -151,6 +167,11 @@ fn write_config(
     writeln!(output, "[Interface]")?;
     writeln!(output, "PrivateKey = {}", &keys.private_key)?;
     writeln!(output, "Address = {}", &config.data.address)?;
+    if !config_opts.no_dns {
+        write!(output, "DNS = ")?;
+        write_list(output, config.data.dns()?)?;
+    }
+    writeln!(output)?;
 
     writeln!(output, "[Peer]")?;
     writeln!(output, "PublicKey = {}", &config.data.public_key)?;
@@ -160,6 +181,21 @@ fn write_config(
     Ok(())
 }
 
+fn write_list<I, T>(output: &mut dyn Write, values: I) -> Result<(), std::io::Error>
+where
+    I: IntoIterator<Item = T>,
+    T: std::fmt::Display,
+{
+    for (i, value) in values.into_iter().enumerate() {
+        if i != 0 {
+            write!(output, ", ")?;
+        }
+        write!(output, "{}", value)?;
+    }
+    writeln!(output)?;
+    Ok(())
+}
+
 fn check(opts: &Opts) -> Result<(), anyhow::Error> {
     let url = format!("{}/check", BASE_URL);
     let result: CheckResult = ureq::get(&url).call()?.into_json()?;