feat: allow domain name as endpoint address (#54)

* Add dns resolution for peer endpoint
* Handle both domain and IP endpoint
* chore: bump version
* Markdown links in function docstrings
* Leave IP resolution to `to_socket_addr()` function

Author: j-chmielewski

Diff for: Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "defguard_wireguard_rs"
-version = "0.4.2"
+version = "0.4.3"
 edition = "2021"
 description = "A unified multi-platform high-level API for managing WireGuard interfaces"
 license = "Apache-2.0"

Diff for: Cargo.toml

@@ -16,7 +16,7 @@ use netlink_packet_wireguard::{
 };
 use serde::{Deserialize, Serialize};
 
-use crate::{key::Key, net::IpAddrMask};
+use crate::{error::WireguardInterfaceError, key::Key, net::IpAddrMask, utils::resolve};
 
 /// WireGuard peer representation.
 #[derive(Debug, Default, PartialEq, Clone, Serialize, Deserialize)]
@@ -53,6 +53,12 @@ impl Peer {
         self.allowed_ips = allowed_ips;
     }
 
+    /// Resolves endpoint address to [SocketAddr] and sets the field
+    pub fn set_endpoint(&mut self, endpoint: &str) -> Result<(), WireguardInterfaceError> {
+        self.endpoint = Some(resolve(endpoint)?);
+        Ok(())
+    }
+
     #[must_use]
     pub fn as_uapi_update(&self) -> String {
         let mut output = format!("public_key={}\n", self.public_key.to_lower_hex());

Diff for: src/host.rs

@@ -121,7 +121,7 @@ where
         });
         let responses = netlink_request_genl::<GenlCtrl>(genlmsg, NLM_F_REQUEST | NLM_F_ACK)?;
 
-        match responses.get(0) {
+        match responses.first() {
             Some(NetlinkMessage {
                 payload:
                     NetlinkPayload::InnerMessage(GenlMessage {

Diff for: src/netlink.rs

@@ -3,7 +3,11 @@ use crate::netlink;
 use crate::{check_command_output_status, Peer, WireguardInterfaceError};
 use std::{collections::HashSet, process::Command};
 #[cfg(any(target_os = "linux", target_os = "freebsd"))]
-use std::{io::Write, net::IpAddr, process::Stdio};
+use std::{
+    io::Write,
+    net::{IpAddr, SocketAddr, ToSocketAddrs},
+    process::Stdio,
+};
 #[cfg(target_os = "macos")]
 use std::{
     io::{BufRead, BufReader, Cursor, Error as IoError},
@@ -340,3 +344,12 @@ pub(crate) fn clean_fwmark_rules(fwmark: u32) -> Result<(), WireguardInterfaceEr
     netlink::delete_main_table_rule(IpVersion::IPv6, 0)?;
     Ok(())
 }
+
+/// Resolves domain name to [SocketAddr]
+pub fn resolve(addr: &str) -> Result<SocketAddr, WireguardInterfaceError> {
+    let error = || WireguardInterfaceError::PeerConfigurationError;
+    addr.to_socket_addrs()
+        .map_err(|_| error())?
+        .next()
+        .ok_or_else(error)
+}