test(server): drop short header packet for unknown connection (#1952)

This commit adds a basic test, passing a short header packet to a fresh server,
expecting the server to drop the packet for the unknown connection.

neqo-transport/tests/server.rs

@@ -258,6 +258,23 @@ fn drop_short_initial() {
  assert!(server.process(Some(&bogus), now()).dgram().is_none());
 }
 
+#[test]
+fn drop_short_header_packet_for_unknown_connection() {
+ const CID: &[u8] = &[55; 8]; // not a real connection ID
+ let mut server = default_server();
+
+ let mut header = neqo_common::Encoder::with_capacity(MIN_INITIAL_PACKET_SIZE);
+ header
+ .encode_byte(0x40) // short header
+ .encode_vec(1, CID)
+ .encode_byte(1);
+ let mut bogus_data: Vec<u8> = header.into();
+ bogus_data.resize(MIN_INITIAL_PACKET_SIZE, 66);
+
+ let bogus = datagram(bogus_data);
+ assert!(server.process(Some(&bogus), now()).dgram().is_none());
+}
+
 /// Verify that the server can read 0-RTT properly. A more robust server would buffer
 /// 0-RTT before the handshake begins and let 0-RTT arrive for a short period after
 /// the handshake completes, but ours is for testing so it only allows 0-RTT while