DirSync::Resp work

Signed-off-by: Luca Fulchir <luca.fulchir@runesauth.com>

src/connection/handshake/dirsync.rs

@@ -11,15 +11,16 @@
 use super::{Error, HandshakeData};
 use crate::{
     auth,
-    connection::ID,
+    connection::{ProtocolVersion, ID},
     enc::{
         asym::{ExchangePubKey, KeyExchange, KeyID},
-        sym::{CipherKind, Secret},
+        sym::{CipherKind, HeadLen, Secret, TagLen},
     },
 };
 
 use ::arrayref::array_mut_ref;
 use ::std::{collections::VecDeque, num::NonZeroU64, vec::Vec};
+use trust_dns_client::rr::rdata::key::Protocol;
 
 type Nonce = [u8; 16];
 
@@ -42,10 +43,15 @@ impl DirSync {
     }
     /// Serialize into raw bytes
     /// NOTE: assumes that there is exactly asa much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         match self {
-            DirSync::Req(req) => req.serialize(out),
+            DirSync::Req(req) => req.serialize(head_len, tag_len, out),
-            DirSync::Resp(resp) => resp.serialize(out),
+            DirSync::Resp(resp) => resp.serialize(head_len, tag_len, out),
         }
     }
 }
@@ -67,9 +73,21 @@ pub struct Req {
 }
 
 impl Req {
-    /// Set the cleartext data after it was parsed
+    /// return the offset of the encrypted data
-    pub fn set_data(&mut self, data: ReqData) {
+    /// NOTE: starts from the beginning of the fenrir packet
-        self.data = ReqInner::Data(data);
+    pub fn encrypted_offset(&self) -> usize {
+        ProtocolVersion::len()
+            + KeyID::len()
+            + KeyExchange::len()
+            + CipherKind::len()
+            + self.exchange_key.len()
+    }
+    /// return the total length of the cleartext data
+    pub fn encrypted_length(&self) -> usize {
+        match &self.data {
+            ReqInner::ClearText(data) => data.len(),
+            _ => 0,
+        }
     }
     /// actual length of the directory synchronized request
     pub fn len(&self) -> usize {
@@ -81,7 +99,12 @@ impl Req {
     }
     /// Serialize into raw bytes
     /// NOTE: assumes that there is exactly as much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         //assert!(out.len() > , ": not enough buffer to serialize");
         todo!()
     }
@@ -108,10 +131,7 @@ impl super::HandshakeParsing for Req {
             Ok(exchange_key) => exchange_key,
             Err(e) => return Err(e.into()),
         };
-        let mut vec = VecDeque::with_capacity(raw.len() - (4 + len));
+        let data = ReqInner::CipherText(raw.len() - (4 + len));
-        vec.extend(raw[(4 + len)..].iter().copied());
-        let _ = vec.make_contiguous();
-        let data = ReqInner::CipherText(vec);
         Ok(HandshakeData::DirSync(DirSync::Req(Self {
             key_id,
             exchange,
@@ -125,40 +145,35 @@ impl super::HandshakeParsing for Req {
 /// Quick way to avoid mixing cipher and clear text
 #[derive(Debug, Clone)]
 pub enum ReqInner {
-    /// Client data, still in ciphertext
+    /// Data is still encrytped, we only keep the length
-    CipherText(VecDeque<u8>),
+    CipherText(usize),
-    /// Client data, decrypted but unprocessed
+    /// Client data, decrypted and parsed
-    ClearText(VecDeque<u8>),
+    ClearText(ReqData),
-    /// Parsed client data
-    Data(ReqData),
 }
 impl ReqInner {
     /// The length of the data
     pub fn len(&self) -> usize {
         match self {
-            ReqInner::CipherText(c) => c.len(),
+            ReqInner::CipherText(len) => *len,
-            ReqInner::ClearText(c) => c.len(),
+            ReqInner::ClearText(data) => data.len(),
-            ReqInner::Data(d) => d.len(),
         }
     }
-    /// Get the ciptertext, or panic
+    /// parse the cleartext
-    pub fn ciphertext<'a>(&'a mut self) -> &'a mut VecDeque<u8> {
+    pub fn deserialize_as_cleartext(&mut self, raw: &[u8]) {
-        match self {
+        let clear = match self {
-            ReqInner::CipherText(data) => data,
+            ReqInner::CipherText(len) => {
-            _ => panic!(),
+                assert!(
+                    *len == raw.len(),
+                    "DirSync::ReqInner::CipherText length mismatch"
+                );
+                match ReqData::deserialize(raw) {
+                    Ok(clear) => clear,
+                    Err(_) => return,
                 }
             }
-    /// switch from ciphertext to cleartext
-    pub fn mark_as_cleartext(&mut self) {
-        let mut newdata: VecDeque<u8>;
-        match self {
-            ReqInner::CipherText(data) => {
-                newdata = VecDeque::new();
-                ::core::mem::swap(&mut newdata, data);
-            }
             _ => return,
-        }
+        };
-        *self = ReqInner::ClearText(newdata);
+        *self = ReqInner::ClearText(clear);
     }
 }
 
@@ -246,12 +261,7 @@ impl ReqData {
     pub const MIN_PKT_LEN: usize =
         16 + KeyID::len() + ID::len() + AuthInfo::MIN_PKT_LEN;
     /// Parse the cleartext raw data
-    pub fn deserialize(raw: &ReqInner) -> Result<Self, Error> {
+    pub fn deserialize(raw: &[u8]) -> Result<Self, Error> {
-        let raw = match raw {
-            // raw is VecDeque, assume everything is on the first slice
-            ReqInner::ClearText(raw) => raw.as_slices().0,
-            _ => return Err(Error::Parsing),
-        };
         if raw.len() < Self::MIN_PKT_LEN {
             return Err(Error::NotEnoughData);
         }
@@ -285,21 +295,19 @@ impl ReqData {
 #[derive(Debug, Clone)]
 pub enum RespInner {
     /// Server data, still in ciphertext
-    CipherText(VecDeque<u8>),
+    CipherText(usize),
-    /// Server data, decrypted but unprocessed
+    /// Parsed, cleartext server data
-    ClearText(VecDeque<u8>),
+    ClearText(RespData),
-    /// Parsed server data
-    Data(RespData),
 }
 impl RespInner {
     /// The length of the data
     pub fn len(&self) -> usize {
         match self {
-            RespInner::CipherText(c) => c.len(),
+            RespInner::CipherText(len) => *len,
-            RespInner::ClearText(c) => c.len(),
+            RespInner::ClearText(d) => RespData::len(),
-            RespInner::Data(d) => RespData::len(),
         }
     }
+    /*
     /// Get the ciptertext, or panic
     pub fn ciphertext<'a>(&'a mut self) -> &'a mut VecDeque<u8> {
         match self {
@@ -307,6 +315,25 @@ impl RespInner {
             _ => panic!(),
         }
     }
+    */
+    /// parse the cleartext
+    pub fn deserialize_as_cleartext(&mut self, raw: &[u8]) {
+        let clear = match self {
+            RespInner::CipherText(len) => {
+                assert!(
+                    *len == raw.len(),
+                    "DirSync::RespInner::CipherText length mismatch"
+                );
+                match RespData::deserialize(raw) {
+                    Ok(clear) => clear,
+                    Err(_) => return,
+                }
+            }
+            _ => return,
+        };
+        *self = RespInner::ClearText(clear);
+    }
+    /*
     /// switch from ciphertext to cleartext
     pub fn mark_as_cleartext(&mut self) {
         let mut newdata: VecDeque<u8>;
@@ -319,6 +346,7 @@ impl RespInner {
         }
         *self = RespInner::ClearText(newdata);
     }
+    */
     /// serialize, but only if ciphertext
     pub fn serialize(&self, out: &mut [u8]) {
         todo!()
@@ -344,31 +372,48 @@ impl super::HandshakeParsing for Resp {
             KeyID(u16::from_le_bytes(raw[0..1].try_into().unwrap()));
         Ok(HandshakeData::DirSync(DirSync::Resp(Self {
             client_key_id,
-            data: RespInner::CipherText(raw[KeyID::len()..].to_vec().into()),
+            data: RespInner::CipherText(raw[KeyID::len()..].len()),
         })))
     }
 }
 
 impl Resp {
+    /// return the offset of the encrypted data
+    /// NOTE: starts from the beginning of the fenrir packet
+    pub fn encrypted_offset(&self) -> usize {
+        ProtocolVersion::len() + KeyID::len()
+    }
+    /// return the total length of the cleartext data
+    pub fn encrypted_length(&self) -> usize {
+        match &self.data {
+            RespInner::ClearText(_data) => RespData::len(),
+            _ => 0,
+        }
+    }
     /// Total length of the response handshake
     pub fn len(&self) -> usize {
         KeyID::len() + self.data.len()
     }
     /// Serialize into raw bytes
     /// NOTE: assumes that there is exactly as much buffer as needed
-    /// NOTE: assumes that the data is encrypted
+    /// NOTE: assumes that the data is *ClearText*
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         assert!(
             out.len() == KeyID::len() + self.data.len(),
             "DirSync Resp: not enough buffer to serialize"
         );
         self.client_key_id.serialize(array_mut_ref![out, 0, 2]);
-        let end_data = 2 + self.data.len();
+        let end_data = (2 + self.data.len()) - tag_len.0;
-        self.data.serialize(&mut out[2..end_data]);
+        self.data.serialize(&mut out[(2 + head_len.0)..end_data]);
     }
     /// Set the cleartext data after it was parsed
     pub fn set_data(&mut self, data: RespData) {
-        self.data = RespInner::Data(data);
+        self.data = RespInner::ClearText(data);
     }
 }
 
@@ -409,7 +454,7 @@ impl RespData {
         out[start..end].copy_from_slice(self.service_key.as_ref());
     }
     /// Parse the cleartext raw data
-    pub fn deserialize(raw: &RespInner) -> Result<Self, Error> {
+    pub fn deserialize(raw: &[u8]) -> Result<Self, Error> {
         todo!();
     }
 }

src/connection/handshake/mod.rs

@@ -4,7 +4,10 @@ pub mod dirsync;
 
 use ::num_traits::FromPrimitive;
 
-use crate::connection::{self, ProtocolVersion};
+use crate::{
+    connection::{self, ProtocolVersion},
+    enc::sym::{HeadLen, TagLen},
+};
 
 /// Handshake errors
 #[derive(::thiserror::Error, Debug, Copy, Clone)]
@@ -53,9 +56,14 @@ impl HandshakeData {
     }
     /// Serialize into raw bytes
     /// NOTE: assumes that there is exactly asa much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         match self {
-            HandshakeData::DirSync(d) => d.serialize(out),
+            HandshakeData::DirSync(d) => d.serialize(head_len, tag_len, out),
         }
     }
 }
@@ -126,10 +134,15 @@ impl Handshake {
     }
     /// serialize the handshake into bytes
     /// NOTE: assumes that there is exactly as much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         assert!(out.len() > 1, "Handshake: not enough buffer to serialize");
         self.fenrir_version.serialize(&mut out[0]);
-        self.data.serialize(&mut out[1..]);
+        self.data.serialize(head_len, tag_len, &mut out[1..]);
     }
 
     pub(crate) fn work(&self, keys: &[HandshakeServer]) -> Result<(), Error> {

src/connection/packet.rs

@@ -1,6 +1,8 @@
 //
 //! Raw packet handling, encryption, decryption, parsing
 
+use crate::enc::sym::{HeadLen, TagLen};
+
 /// Fenrir Connection id
 /// 0 is special as it represents the handshake
 /// Connection IDs are to be considered u64 little endian
@@ -100,10 +102,15 @@ impl PacketData {
     }
     /// serialize data into bytes
     /// NOTE: assumes that there is exactly asa much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         assert!(self.len() == out.len(), "PacketData: wrong buffer length");
         match self {
-            PacketData::Handshake(h) => h.serialize(out),
+            PacketData::Handshake(h) => h.serialize(head_len, tag_len, out),
         }
     }
 }
@@ -124,12 +131,18 @@ impl Packet {
     }
     /// serialize packet into buffer
     /// NOTE: assumes that there is exactly asa much buffer as needed
-    pub fn serialize(&self, out: &mut [u8]) {
+    pub fn serialize(
+        &self,
+        head_len: HeadLen,
+        tag_len: TagLen,
+        out: &mut [u8],
+    ) {
         assert!(
             out.len() > ConnectionID::len(),
             "Packet: not enough buffer to serialize"
         );
         self.id.serialize(&mut out[0..ConnectionID::len()]);
-        self.data.serialize(&mut out[ConnectionID::len()..]);
+        self.data
+            .serialize(head_len, tag_len, &mut out[ConnectionID::len()..]);
     }
 }

src/enc/sym.rs

@@ -59,9 +59,9 @@ impl CipherKind {
         1
     }
     /// required length of the nonce
-    pub fn nonce_len(&self) -> usize {
+    pub fn nonce_len(&self) -> HeadLen {
         // TODO: how the hell do I take this from ::chacha20poly1305?
-        Nonce::len()
+        HeadLen(Nonce::len())
     }
     /// required length of the key
     pub fn key_len(&self) -> usize {
@@ -69,9 +69,9 @@ impl CipherKind {
         XChaCha20Poly1305::key_size()
     }
     /// Length of the authentication tag
-    pub fn tag_len(&self) -> usize {
+    pub fn tag_len(&self) -> TagLen {
         // TODO: how the hell do I take this from ::chacha20poly1305?
-        ::ring::aead::CHACHA20_POLY1305.tag_len()
+        TagLen(::ring::aead::CHACHA20_POLY1305.tag_len())
     }
 }
 
@@ -90,6 +90,16 @@ pub enum CipherDirection {
     Send,
 }
 
+/// strong typedef for header length
+/// aka: nonce length in the encrypted data)
+#[derive(Debug, Copy, Clone)]
+pub struct HeadLen(pub usize);
+/// strong typedef for the Tag length
+/// aka: cryptographic authentication tag length at the end
+/// of the encrypted data
+#[derive(Debug, Copy, Clone)]
+pub struct TagLen(pub usize);
+
 /// actual ciphers
 enum Cipher {
     /// Cipher XChaha20_Poly1305
@@ -105,31 +115,33 @@ impl Cipher {
             }
         }
     }
-    fn nonce_len(&self) -> usize {
+    fn nonce_len(&self) -> HeadLen {
         match self {
             Cipher::XChaCha20Poly1305(_) => {
                 // TODO: how the hell do I take this from ::chacha20poly1305?
-                ::ring::aead::CHACHA20_POLY1305.nonce_len()
+                HeadLen(::ring::aead::CHACHA20_POLY1305.nonce_len())
             }
         }
     }
-    fn tag_len(&self) -> usize {
+    fn tag_len(&self) -> TagLen {
         match self {
             Cipher::XChaCha20Poly1305(_) => {
                 // TODO: how the hell do I take this from ::chacha20poly1305?
-                ::ring::aead::CHACHA20_POLY1305.tag_len()
+                TagLen(::ring::aead::CHACHA20_POLY1305.tag_len())
             }
         }
     }
-    fn decrypt(&self, aad: AAD, data: &mut VecDeque<u8>) -> Result<(), Error> {
+    fn decrypt<'a>(
+        &self,
+        aad: AAD,
+        raw_data: &'a mut [u8],
+    ) -> Result<&'a [u8], Error> {
         match self {
             Cipher::XChaCha20Poly1305(cipher) => {
                 use ::chacha20poly1305::{
                     aead::generic_array::GenericArray, AeadInPlace,
                 };
-                let final_len: usize;
+                let final_len: usize = {
-                {
-                    let raw_data = data.as_mut_slices().0;
                     // FIXME: check min data length
                     let (nonce_bytes, data_and_tag) = raw_data.split_at_mut(13);
                     let (data_notag, tag_bytes) = data_and_tag.split_at_mut(
@@ -147,11 +159,11 @@ impl Cipher {
                     if maybe.is_err() {
                         return Err(Error::Decrypt);
                     }
-                    final_len = data_notag.len();
+                    data_notag.len()
-                }
+                };
-                data.drain(..Nonce::len());
+                //data.drain(..Nonce::len());
-                data.truncate(final_len);
+                //data.truncate(final_len);
-                Ok(())
+                Ok(&raw_data[Nonce::len()..Nonce::len() + final_len])
             }
         }
     }
@@ -159,7 +171,7 @@ impl Cipher {
         match self {
             Cipher::XChaCha20Poly1305(cipher) => {
                 let cipher = CipherKind::XChaCha20Poly1305;
-                cipher.nonce_len() + cipher.tag_len()
+                cipher.nonce_len().0 + cipher.tag_len().0
             }
         }
     }
@@ -167,28 +179,30 @@ impl Cipher {
         &self,
         nonce: &Nonce,
         aad: AAD,
-        data: &mut Data,
+        data: &mut [u8],
     ) -> Result<(), Error> {
-        // No need to check for minimum buffer size since `Data` assures we
+        // FIXME: check minimum buffer size 
-        // already went through that
         match self {
             Cipher::XChaCha20Poly1305(cipher) => {
                 use ::chacha20poly1305::{
                     aead::generic_array::GenericArray, AeadInPlace,
                 };
+                let tag_len: usize = ::ring::aead::CHACHA20_POLY1305.tag_len();
+                let data_len_notag = data.len() - tag_len;
                 // write nonce
-                data.get_slice_full()[..Nonce::len()]
+                data[..Nonce::len()].copy_from_slice(nonce.as_bytes());
-                    .copy_from_slice(nonce.as_bytes());
 
                 // encrypt data
                 match cipher.cipher.encrypt_in_place_detached(
                     nonce.as_bytes().into(),
                     aad.0,
-                    data.get_slice(),
+                    &mut data[Nonce::len()..data_len_notag],
                 ) {
                     Ok(tag) => {
+                        data[data_len_notag..]
                             // add tag
-                        data.get_tag_slice().copy_from_slice(tag.as_slice());
+                            //data.get_tag_slice()
+                            .copy_from_slice(tag.as_slice());
                         Ok(())
                     }
                     Err(_) => Err(Error::Encrypt),
@@ -216,7 +230,7 @@ impl CipherRecv {
         Self(Cipher::new(kind, secret))
     }
     /// Get the length of the nonce  for this cipher
-    pub fn nonce_len(&self) -> usize {
+    pub fn nonce_len(&self) -> HeadLen {
         self.0.nonce_len()
     }
     /// Decrypt a paket. Nonce and Tag are taken from the packet,
@@ -224,8 +238,8 @@ impl CipherRecv {
     pub fn decrypt<'a>(
         &self,
         aad: AAD,
-        data: &mut VecDeque<u8>,
+        data: &'a mut [u8],
-    ) -> Result<(), Error> {
+    ) -> Result<&'a [u8], Error> {
         self.0.decrypt(aad, data)
     }
 }
@@ -289,12 +303,12 @@ impl CipherSend {
     pub fn make_data(&self, length: usize) -> Data {
         Data {
             data: Vec::with_capacity(length + self.cipher.overhead()),
-            skip_start: self.cipher.nonce_len(),
+            skip_start: self.cipher.nonce_len().0,
-            skip_end: self.cipher.tag_len(),
+            skip_end: self.cipher.tag_len().0,
         }
     }
     /// Encrypt the given data
-    pub fn encrypt(&self, aad: AAD, data: &mut Data) -> Result<(), Error> {
+    pub fn encrypt(&self, aad: AAD, data: &mut [u8]) -> Result<(), Error> {
         let old_nonce = self.nonce.advance();
         self.cipher.encrypt(&old_nonce, aad, data)?;
         Ok(())

src/lib.rs

@@ -28,7 +28,7 @@ use ::tokio::{
 use crate::enc::{
     asym,
     hkdf::HkdfSha3,
-    sym::{CipherKind, CipherRecv, CipherSend},
+    sym::{CipherKind, CipherRecv, CipherSend, HeadLen, TagLen},
 };
 pub use config::Config;
 use connection::{
@@ -67,13 +67,26 @@ pub struct AuthNeededInfo {
     pub cipher: CipherKind,
 }
 
+/// Client information needed to fully establish the conenction
+#[derive(Debug)]
+pub struct ClientConnectInfo {
+    /// Parsed handshake
+    pub handshake: Handshake,
+    /// hkdf generated from the handshake
+    pub hkdf: HkdfSha3,
+    /// cipher to be used in both directions
+    pub cipher_recv: CipherRecv,
+}
+
 /// Intermediate actions to be taken while parsing the handshake
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum HandshakeAction {
     /// Parsing finished, all ok, nothing to do
     None,
     /// Packet parsed, now go perform authentication
     AuthNeeded(AuthNeededInfo),
+    /// the client can fully establish a connection with this info
+    ClientConnect(ClientConnectInfo),
 }
 // No async here
 struct FenrirInner {
@@ -95,6 +108,7 @@ impl FenrirInner {
     fn recv_handshake(
         &self,
         mut handshake: Handshake,
+        handshake_raw: &mut [u8],
     ) -> Result<HandshakeAction, Error> {
         use connection::handshake::{
             dirsync::{self, DirSync},
@@ -159,13 +173,17 @@ impl FenrirInner {
                     let cipher_recv = CipherRecv::new(req.cipher, secret_recv);
                     use crate::enc::sym::AAD;
                     let aad = AAD(&mut []); // no aad for now
-                    match cipher_recv.decrypt(aad, &mut req.data.ciphertext()) {
+                    match cipher_recv.decrypt(
-                        Ok(()) => req.data.mark_as_cleartext(),
+                        aad,
+                        &mut handshake_raw[req.encrypted_offset()..],
+                    ) {
+                        Ok(cleartext) => {
+                            req.data.deserialize_as_cleartext(cleartext)
+                        }
                         Err(e) => {
                             return Err(handshake::Error::Key(e).into());
                         }
                     }
-                    req.set_data(dirsync::ReqData::deserialize(&req.data)?);
 
                     let cipher = req.cipher;
 
@@ -200,17 +218,26 @@ impl FenrirInner {
                     let cipher_recv =
                         CipherRecv::new(hshake.cipher, secret_recv);
                     use crate::enc::sym::AAD;
-                    let aad = AAD(&mut []); // no aad for now
+                    // no aad for now
-                    match cipher_recv.decrypt(aad, &mut resp.data.ciphertext())
+                    let aad = AAD(&mut []);
-                    {
+                    let mut raw_data = &mut handshake_raw[resp
-                        Ok(()) => resp.data.mark_as_cleartext(),
+                        .encrypted_offset()
+                        ..(resp.encrypted_offset() + resp.encrypted_length())];
+                    match cipher_recv.decrypt(aad, &mut raw_data) {
+                        Ok(cleartext) => {
+                            resp.data.deserialize_as_cleartext(&cleartext)
+                        }
                         Err(e) => {
                             return Err(handshake::Error::Key(e).into());
                         }
                     }
-                    resp.set_data(dirsync::RespData::deserialize(&resp.data)?);
+                    return Ok(HandshakeAction::ClientConnect(
-
+                        ClientConnectInfo {
-                    todo!();
+                            handshake,
+                            hkdf: hshake.hkdf,
+                            cipher_recv,
+                        },
+                    ));
                 }
             },
         }
@@ -615,7 +642,7 @@ impl Fenrir {
 
     const MIN_PACKET_BYTES: usize = 8;
     /// Read and do stuff with the raw udp packet
-    async fn recv(&self, udp: RawUdp) {
+    async fn recv(&self, mut udp: RawUdp) {
         if udp.data.len() < Self::MIN_PACKET_BYTES {
             return;
         }
@@ -630,7 +657,9 @@ impl Fenrir {
                     return;
                 }
             };
-            let action = match self._inner.recv_handshake(handshake) {
+            let action =
+                match self._inner.recv_handshake(handshake, &mut udp.data[8..])
+                {
                     Ok(action) => action,
                     Err(err) => {
                         ::tracing::debug!("Handshake recv error {}", err);
@@ -657,10 +686,10 @@ impl Fenrir {
                             DirSync::Req(req) => {
                                 use dirsync::ReqInner;
                                 let req_data = match req.data {
-                                    ReqInner::Data(req_data) => req_data,
+                                    ReqInner::ClearText(req_data) => req_data,
                                     _ => {
                                         ::tracing::error!(
-                                            "token_check: expected Data"
+                                            "token_check: expected ClearText"
                                         );
                                         return;
                                     }
@@ -697,6 +726,8 @@ impl Fenrir {
                                     connection::ID::new_rand(&self.rand);
                                 let srv_secret =
                                     enc::sym::Secret::new_rand(&self.rand);
+                                let head_len = req.cipher.nonce_len();
+                                let tag_len = req.cipher.tag_len();
 
                                 let raw_conn = Connection::new(
                                     authinfo.hkdf,
@@ -711,9 +742,6 @@ impl Fenrir {
                                     lock.reserve_first(raw_conn)
                                 };
 
-                                // TODO: move all the next bits into
-                                // dirsync::Req::respond(...)
-
                                 let resp_data = dirsync::RespData {
                                     client_nonce: req_data.nonce,
                                     id: auth_conn.id,
@@ -721,25 +749,18 @@ impl Fenrir {
                                     service_key: srv_secret,
                                 };
                                 use crate::enc::sym::AAD;
-                                let aad = AAD(&mut []); // no aad for now
+                                // no aad for now
-                                let mut data = auth_conn
+                                let aad = AAD(&mut []);
-                                    .cipher_send
-                                    .make_data(dirsync::RespData::len());
 
-                                if let Err(e) = auth_conn
-                                    .cipher_send
-                                    .encrypt(aad, &mut data)
-                                {
-                                    ::tracing::error!("can't encrypt: {:?}", e);
-                                    return;
-                                }
                                 use dirsync::RespInner;
                                 let resp = dirsync::Resp {
                                     client_key_id: req_data.client_key_id,
-                                    data: RespInner::CipherText(
+                                    data: RespInner::ClearText(resp_data),
-                                        data.get_raw().into(),
-                                    ),
                                 };
+                                let offset_to_encrypt = resp.encrypted_offset();
+                                let encrypt_until = offset_to_encrypt
+                                    + resp.encrypted_length()
+                                    + tag_len.0;
                                 let resp_handshake = Handshake::new(
                                     HandshakeData::DirSync(DirSync::Resp(resp)),
                                 );
@@ -750,7 +771,20 @@ impl Fenrir {
                                 };
                                 let mut raw_out =
                                     Vec::<u8>::with_capacity(packet.len());
-                                packet.serialize(&mut raw_out);
+                                packet.serialize(
+                                    head_len,
+                                    tag_len,
+                                    &mut raw_out,
+                                );
+
+                                if let Err(e) = auth_conn.cipher_send.encrypt(
+                                    aad,
+                                    &mut raw_out
+                                        [offset_to_encrypt..encrypt_until],
+                                ) {
+                                    ::tracing::error!("can't encrypt: {:?}", e);
+                                    return;
+                                }
                                 self.send_packet(raw_out, udp.src, udp.dst)
                                     .await;
                             }