Improve variable names, comments and error messages

Briefly explain the usage.
Make it clearer that the program does not work with an IPv6.
Remove the somewhat confusing usage of `trim`. The IP is not trimmed
either and it would only protect from a purposefully wrong argument
(With quoted or escaped spaces.)
Explain what the boolean parameters stand for.
Explain why the PSK has to be printed with `fmt::Debug`.

1 files changed, 16 insertions, 10 deletions

diff --git a/talpid-tunnel-config-client/examples/psk-exchange.rs b/talpid-tunnel-config-client/examples/psk-exchange.rs
index bda08f3187..48643805fc 100644
--- a/talpid-tunnel-config-client/examples/psk-exchange.rs
+++ b/talpid-tunnel-config-client/examples/psk-exchange.rs
@@ -1,6 +1,9 @@
 //! Example client implementing the quantum resistant tunnel PSK exchange.
 //! Useful to test this crate's implementation.
 
+// 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};
 
@@ -11,23 +14,26 @@ async fn main() {
         .next()
         .expect("Give tuncfg server IP as first argument")
         .parse()
-        .expect("tuncfg ip argument not a valid IP");
-    let pubkey_string = args
+        .expect("tuncfg IP argument not a valid IPv4");
+    let public_key_string = args
         .next()
         .expect("Give WireGuard public key as second argument");
-    let pubkey = PublicKey::from_base64(pubkey_string.trim()).expect("Invalid public key");
-    let private_key = PrivateKey::new_from_random();
+    let public_key = PublicKey::from_base64(&public_key_string).expect("Invalid public key");
+    // The ephemeral peer requires an ephemeral public WireGuard key,
+    // which can also be provided by other means.
+    let ephemeral_private_key = PrivateKey::new_from_random();
 
     let ephemeral_peer = talpid_tunnel_config_client::request_ephemeral_peer(
         tuncfg_server_ip,
-        pubkey,
-        private_key.public_key(),
-        true,
-        false,
+        public_key, // Parent connection's public key.
+        ephemeral_private_key.public_key(),
+        true,  // Whether to negotiate a "PQ-safe" PSK.
+        false, // Whether to use DAITA (Does not work with Linux kernel WireGuard.)
     )
     .await
     .unwrap();
 
-    println!("private key: {private_key:?}");
-    println!("psk: {:?}", ephemeral_peer.psk.unwrap());
+    println!("Private key: {ephemeral_private_key}");
+    // Use fmt::Debug since Serialize is not implemented for PresharedKey.
+    println!("PSK: {:?}", ephemeral_peer.psk.unwrap());
 }