+pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
+ payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
+}
+
+/// panics if payloads_serialized_length(payloads) > packet_data_len
+pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
+ payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize) -> P
+{
+ let mut packet_data = vec![0; packet_data_len];
+
+ let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
+ chacha.process_in_place(&mut packet_data);
+
+ construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
+}
+
+/// panics if payloads_serialized_length(payloads) > packet_data.len()