Fix a lingering panic by using a stricter type

The functions `request_ephemeral_peer` and consecutively `new_client`
accepted an `IpAddr`, but due to only ever preparing a v4 socket this
lead to panic due to an `EAFNOSUPPORT` error if an IPv6 was provided.

It would also have made sense to change `new_client` to create either
an IPv4 or IPv6 socket depending on the type of the address, but the
tuncfg service is currently not accepting IPv6 connections, therefore
this was the cleaner change.

talpid-tunnel-config-client/examples/psk-exchange.rs

@@ -4,7 +4,6 @@
 // Usage: ./psk-exchange <tuncfg_server_ip> <wireguard_public_key>
 // e. g. ./psk-exchange 10.64.0.1 NkECLsf+VbZUjve7RVN6sE3NYUcYUmUn8qpFugqbXFk=
 
-use std::net::IpAddr;
 use talpid_types::net::wireguard::{PrivateKey, PublicKey};
 
 #[tokio::main]
@@ -24,7 +23,7 @@ async fn main() {
     let ephemeral_private_key = PrivateKey::new_from_random();
 
     let ephemeral_peer = talpid_tunnel_config_client::request_ephemeral_peer(
-        IpAddr::V4(tuncfg_server_ip),
+        tuncfg_server_ip,
         public_key, // Parent connection's public key.
         ephemeral_private_key.public_key(),
         true,  // Whether to negotiate a "PQ-safe" PSK.

talpid-tunnel-config-client/src/lib.rs

@@ -1,9 +1,9 @@
 use proto::PostQuantumRequestV1;
 use std::fmt;
 #[cfg(not(target_os = "ios"))]
-use std::net::IpAddr;
-#[cfg(not(target_os = "ios"))]
 use std::net::SocketAddr;
+#[cfg(not(target_os = "ios"))]
+use std::net::{IpAddr, Ipv4Addr};
 use talpid_types::net::wireguard::{PresharedKey, PublicKey};
 #[cfg(not(target_os = "ios"))]
 use tokio::net::TcpSocket;
@@ -189,7 +189,7 @@ pub async fn request_ephemeral_peer_with(
 /// Negotiate a short-lived peer with a PQ-safe PSK or with DAITA enabled.
 #[cfg(not(target_os = "ios"))]
 pub async fn request_ephemeral_peer(
-    service_address: IpAddr,
+    service_address: Ipv4Addr,
     parent_pubkey: PublicKey,
     ephemeral_pubkey: PublicKey,
     enable_post_quantum: bool,
@@ -245,8 +245,9 @@ fn xor_assign(dst: &mut [u8; 32], src: &[u8; 32]) {
 }
 
 #[cfg(not(target_os = "ios"))]
-async fn new_client(addr: IpAddr) -> Result<RelayConfigService, Error> {
+async fn new_client(addr: Ipv4Addr) -> Result<RelayConfigService, Error> {
     let endpoint = Endpoint::from_static("tcp://0.0.0.0:0");
+    let addr = IpAddr::V4(addr);
 
     let conn = endpoint
         .connect_with_connector(service_fn(move |_| async move {

talpid-wireguard/src/lib.rs

@@ -730,7 +730,7 @@ impl WireguardMonitor {
         let ephemeral = tokio::time::timeout(
             timeout,
             talpid_tunnel_config_client::request_ephemeral_peer(
-                IpAddr::from(config.ipv4_gateway),
+                config.ipv4_gateway,
                 config.tunnel.private_key.public_key(),
                 wg_psk_pubkey,
                 enable_pq,