crypto: expose negociated_key_exchange_group in the handshake data

quinn-proto/src/crypto/rustls.rs

@@ -11,7 +11,7 @@ use rustls::{
     client::danger::ServerCertVerifier,
     pki_types::{CertificateDer, PrivateKeyDer, ServerName},
     quic::{Connection, HeaderProtectionKey, KeyChange, PacketKey, Secrets, Suite, Version},
-    CipherSuite,
+    CipherSuite, NamedGroup,
 };
 
 use crate::{
@@ -69,6 +69,11 @@ impl crypto::Session for TlsSession {
                 .negotiated_cipher_suite()
                 .expect("cipher is negotiated")
                 .suite(),
+            negociated_key_exchange_group: self
+                .inner
+                .negotiated_key_exchange_group()
+                .expect("key exchange group is negociated")
+                .name(),
         }))
     }
 
@@ -263,6 +268,8 @@ pub struct HandshakeData {
     pub server_name: Option<String>,
     /// The ciphersuite negotiated with the peer
     pub negotiated_cipher_suite: CipherSuite,
+    /// The key exchange group negotiated with the peer
+    pub negotiated_key_exchange_group: NamedGroup,
 }
 
 /// A QUIC-compatible TLS client configuration