Add HandshakeConfig. Clean up hs pattern/name stuff

Author: cowlicks

src/crypto/handshake.rs

@@ -3,6 +3,7 @@ use blake2::{
     digest::{typenum::U32, FixedOutput, Update},
     Blake2bMac,
 };
+use handshake_patterns::name_from_pattern;
 use snow::{
     params::HandshakePattern,
     resolvers::{DefaultResolver, FallbackResolver},
@@ -16,6 +17,7 @@ const CIPHERKEYLEN: usize = 32;
 /// The [`HandshakePattern`]s we support for connections
 pub mod handshake_patterns {
     use snow::params::HandshakePattern;
+    use tracing::error;
     /// [`HandshakePattern`] used by the hyperdht crate.
     pub const DHT: HandshakePattern = HandshakePattern::IK;
     /// Noise protocol name used in hyperdht crate.
@@ -24,6 +26,18 @@ pub mod handshake_patterns {
     pub const PROTOCOL: HandshakePattern = HandshakePattern::XX;
     /// Noise protocol name used in hypercore-protocol crate.
     pub const PROTOCOL_NAME: &str = "Noise_XX_Ed25519_ChaChaPoly_BLAKE2b";
+
+    /// Get a Noise protocol name from a handshake pattern
+    pub fn name_from_pattern(pattern: &HandshakePattern) -> Result<&'static str, snow::Error> {
+        Ok(match *pattern {
+            DHT => DHT_NAME,
+            PROTOCOL => PROTOCOL_NAME,
+            unsupported_pattern => {
+                error!("Got an unsupported handshake pattern {unsupported_pattern:?}");
+                return Err(snow::Error::Input);
+            }
+        })
+    }
 }
 
 // These the output of, see `hash_namespace` test below for how they are produced
@@ -200,6 +214,38 @@ impl Handshake {
     }
 }
 
+/// Configuration for creating a handshake with specific parameters
+#[derive(Debug, Clone)]
+pub struct HandshakeConfig {
+    /// The noise handshake pattern to use (XX, IK, etc.)
+    pub pattern: HandshakePattern,
+    /// Optional prologue data to include in the handshake
+    pub prologue: Option<Vec<u8>>,
+    /// Remote public key (required for IK pattern initiator)
+    // TODO replace with an actual key type
+    pub remote_public_key: Option<[u8; 32]>,
+}
+
+impl HandshakeConfig {
+    fn new(
+        pattern: HandshakePattern,
+        prologue: Option<Vec<u8>>,
+        remote_public_key: Option<[u8; 32]>,
+    ) -> Self {
+        Self {
+            pattern,
+            prologue,
+            remote_public_key,
+        }
+    }
+}
+
+impl Default for HandshakeConfig {
+    fn default() -> Self {
+        Self::new(HandshakePattern::XX, None, None)
+    }
+}
+
 fn build_handshake_state(
     is_initiator: bool,
 ) -> std::result::Result<(HandshakeState, Vec<u8>), SnowError> {
@@ -215,14 +261,10 @@ fn build_handshake_state_with_config(
         NoiseParams,
     };
 
-    let pattern_str = match config.pattern {
-        HandshakePattern::XX => "Noise_XX_Ed25519_ChaChaPoly_BLAKE2b",
-        HandshakePattern::IK => "Noise_IK_Ed25519_ChaChaPoly_BLAKE2b",
-        _ => return Err(SnowError::Input),
-    };
+    let hs_name = name_from_pattern(&config.pattern)?;
 
     let noise_params = NoiseParams::new(
-        pattern_str.to_string(),
+        hs_name.to_string(),
         BaseChoice::Noise,
         HandshakeChoice {
             pattern: config.pattern,