feat(bindings): Add API to check for resumption (#4552)

Author: goatgoose

bindings/rust/s2n-tls/src/connection.rs

@@ -1044,6 +1044,11 @@ impl Connection {
             Ok(())
         }
     }
+
+    /// Determines whether the connection was resumed from an earlier handshake.
+    pub fn resumed(&self) -> bool {
+        unsafe { s2n_connection_is_session_resumed(self.connection.as_ptr()) == 1 }
+    }
 }
 
 struct Context {

bindings/rust/s2n-tls/src/testing/resumption.rs

@@ -109,10 +109,7 @@ mod tests {
         let client = pair.client.0.connection();
 
         // Check connection was full handshake and a session ticket was included
-        assert_eq!(
-            client.handshake_type()?,
-            "NEGOTIATED|FULL_HANDSHAKE|TLS12_PERFECT_FORWARD_SECRECY|WITH_SESSION_TICKET"
-        );
+        assert!(!client.resumed());
         validate_session_ticket(client)?;
 
         // create and configure a client/server connection again
@@ -138,7 +135,7 @@ mod tests {
         let server = pair.server.0.connection();
 
         // Check new connection was resumed
-        assert_eq!(client.handshake_type()?, "NEGOTIATED");
+        assert!(client.resumed());
         // validate that a ticket is available
         validate_session_ticket(client)?;
         validate_session_ticket(server)?;
@@ -195,10 +192,7 @@ mod tests {
 
         let client = pair.client.0.connection();
         // Check connection was full handshake
-        assert_eq!(
-            client.handshake_type()?,
-            "NEGOTIATED|FULL_HANDSHAKE|MIDDLEBOX_COMPAT"
-        );
+        assert!(!client.resumed());
         // validate that a ticket is available
         validate_session_ticket(client)?;
 
@@ -227,7 +221,7 @@ mod tests {
 
         let client = pair.client.0.connection();
         // Check new connection was resumed
-        assert_eq!(client.handshake_type()?, "NEGOTIATED|MIDDLEBOX_COMPAT");
+        assert!(client.resumed());
         // validate that a ticket is available
         validate_session_ticket(client)?;
         Ok(())