Add IP4P domain resolve support

phantun/Cargo.toml

@@ -22,3 +22,4 @@ tokio-tun = "0.11"
 num_cpus = "1.13"
 neli = "0.6"
 nix = { version = "0.28", features = ["net"] }
+dns-lookup = "2.0.4"

phantun/src/bin/client.rs

@@ -2,7 +2,7 @@ use clap::{crate_version, Arg, ArgAction, Command};
 use fake_tcp::packet::MAX_PACKET_LEN;
 use fake_tcp::{Socket, Stack};
 use log::{debug, error, info};
-use phantun::utils::{assign_ipv6_address, new_udp_reuseport};
+use phantun::utils::{assign_ipv6_address, new_udp_reuseport, lookup_host};
 use std::collections::HashMap;
 use std::fs;
 use std::io;
@@ -35,8 +35,8 @@ async fn main() -> io::Result<()> {
                 .short('r')
                 .long("remote")
                 .required(true)
-                .value_name("IP or HOST NAME:PORT")
-                .help("Sets the address or host name and port where Phantun Client connects to Phantun Server, IPv6 address need to be specified as: \"[IPv6]:PORT\"")
+                .value_name("IP:PORT or HOST_NAME:PORT or IP4P_DOMIAN:0")
+                .help("Sets the address or host name and port where Phantun Client connects to Phantun Server, IPv6 address need to be specified as: \"[IPv6]:PORT\", IP4P Domain need to be specified as: \"DOMAIN:0\"")
         )
         .arg(
             Arg::new("tun")
@@ -101,6 +101,14 @@ async fn main() -> io::Result<()> {
                       Note: ensure this file's size does not exceed the MTU of the outgoing interface. \
                       The content is always sent out in a single packet and will not be further segmented")
         )
+        .arg(
+            Arg::new("ip4p_remote")
+                .long("ip4p-remote")
+                .short('n')
+                .required(false)
+                .action(ArgAction::SetTrue) 
+                .help("Use IP4P domain to resolve remote address")
+        )
         .get_matches();
 
     let local_addr: SocketAddr = matches
@@ -111,12 +119,9 @@ async fn main() -> io::Result<()> {
 
     let ipv4_only = matches.get_flag("ipv4_only");
 
-    let remote_addr = tokio::net::lookup_host(matches.get_one::<String>("remote").unwrap())
-        .await
-        .expect("bad remote address or host")
-        .find(|addr| !ipv4_only || addr.is_ipv4())
-        .expect("unable to resolve remote host name");
-    info!("Remote address is: {}", remote_addr);
+    let ip4p_resolve = matches.get_flag("ip4p_remote");
+
+    let remote_addr = lookup_host(matches.get_one::<String>("remote").unwrap(), ip4p_resolve, ipv4_only).await;
 
     let tun_local: Ipv4Addr = matches
         .get_one::<String>("tun_local")

phantun/src/utils.rs

@@ -9,7 +9,7 @@ use neli::{
     socket::NlSocketHandle,
     types::RtBuffer,
 };
-use std::net::{Ipv6Addr, SocketAddr};
+use std::net::{Ipv4Addr, Ipv6Addr, SocketAddr};
 use tokio::net::UdpSocket;
 
 pub fn new_udp_reuseport(local_addr: SocketAddr) -> UdpSocket {
@@ -58,3 +58,37 @@ pub fn assign_ipv6_address(device_name: &str, local: Ipv6Addr, peer: Ipv6Addr) {
     );
     rtnl.send(nl_header).unwrap();
 }
+
+pub async fn lookup_host(domain: &str, ip4p_resolve: bool, ipv4_only: bool) -> std::net::SocketAddr {
+    if ip4p_resolve {
+        return resolve_ip4p_domain(domain);
+    }
+    return tokio::net::lookup_host(domain)
+        .await
+        .expect("bad remote address or host")
+        .find(|addr| !ipv4_only || addr.is_ipv4())
+        .expect("unable to resolve remote host name");
+}
+
+fn resolve_ip4p_domain(domain: &str) -> std::net::SocketAddr {
+    let ip4p_addr = dns_lookup::lookup_host(domain.trim_end_matches(":0")).unwrap();
+    let ip4p_addr = ip4p_addr[0].to_string();
+    let ip4p_resolve: Vec<&str> = ip4p_addr.split(':').collect();
+    if ip4p_resolve.len() != 5 {
+        panic!("Invalid IP4P values: {:?}", ip4p_resolve);
+    }
+    let port = u16::from_str_radix(ip4p_resolve[2], 16).expect("Invalid port value");
+    let ipab = u16::from_str_radix(ip4p_resolve[3], 16).expect("Invalid ipab value");
+    let ipcd = u16::from_str_radix(ip4p_resolve[4], 16).expect("Invalid ipcd value");
+
+    let ipa = ipab >> 8;
+    let ipb = ipab & 0xff;
+    let ipc = ipcd >> 8;
+    let ipd = ipcd & 0xff;
+
+    let remote_addr = SocketAddr::new(
+        Ipv4Addr::new(ipa.try_into().unwrap(), ipb.try_into().unwrap(), ipc.try_into().unwrap(), ipd.try_into().unwrap()).into(),
+        port.try_into().unwrap()
+    );
+    return remote_addr;
+}