diff --git a/src/main.rs b/src/main.rs
index 727f575..27d517e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,14 +2,13 @@
 
 mod bag;
 mod skeleton;
+mod packets;
 
-use bytes::BytesMut;
 use core::time::Duration;
 use futures::select;
 use preserves::value::{self, Map};
-use std::io;
 use std::sync::{Mutex, RwLock, Arc};
-use tokio::codec::{Framed, Encoder, Decoder};
+use tokio::codec::Framed;
 use tokio::net::{TcpListener, TcpStream};
 use tokio::prelude::*;
 use tokio::sync::mpsc::{unbounded_channel, UnboundedSender, UnboundedReceiver};
@@ -19,130 +18,7 @@ use tokio::timer::Interval;
 
 type ConnId = u64;
 
-// type V = value::PlainValue;
-type V = value::ArcValue;
-
-mod packets {
-    use super::V;
-
-    pub type EndpointName = V;
-    pub type Assertion = V;
-    pub type Captures = Vec<Assertion>;
-
-    #[derive(Debug, serde::Serialize, serde::Deserialize)]
-    pub enum Action {
-        Assert(EndpointName, Assertion),
-        Clear(EndpointName),
-        Message(Assertion),
-    }
-
-    #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
-    pub enum Event {
-        Add(EndpointName, Captures),
-        Del(EndpointName, Captures),
-        Msg(EndpointName, Captures),
-        End(EndpointName),
-    }
-
-    #[derive(Debug, serde::Serialize, serde::Deserialize)]
-    pub enum In {
-        Connect(V),
-        Turn(Vec<Action>),
-        Ping(),
-        Pong(),
-    }
-
-    #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
-    pub enum Out {
-        Err(String),
-        Turn(Vec<Event>),
-        Ping(),
-        Pong(),
-    }
-}
-
-#[derive(Debug)]
-enum PacketDecodeError {
-    Read(value::decoder::Error),
-    Parse(value::error::Error),
-}
-
-impl From<io::Error> for PacketDecodeError {
-    fn from(v: io::Error) -> Self {
-        PacketDecodeError::Read(v.into())
-    }
-}
-
-impl From<value::error::Error> for PacketDecodeError {
-    fn from(v: value::error::Error) -> Self {
-        PacketDecodeError::Parse(v)
-    }
-}
-
-#[derive(Debug)]
-enum PacketEncodeError {
-    Write(value::encoder::Error),
-    Unparse(value::error::Error),
-}
-
-impl From<io::Error> for PacketEncodeError {
-    fn from(v: io::Error) -> Self {
-        PacketEncodeError::Write(v.into())
-    }
-}
-
-impl From<value::error::Error> for PacketEncodeError {
-    fn from(v: value::error::Error) -> Self {
-        PacketEncodeError::Unparse(v)
-    }
-}
-
-impl From<PacketEncodeError> for io::Error {
-    fn from(v: PacketEncodeError) -> Self {
-        match v {
-            PacketEncodeError::Write(e) => e,
-            PacketEncodeError::Unparse(e) =>
-                Self::new(io::ErrorKind::InvalidData, format!("{:?}", e)),
-        }
-    }
-}
-
-struct PacketCodec {
-    codec: value::Codec<V>,
-}
-
-impl PacketCodec {
-    fn new(codec: value::Codec<V>) -> Self {
-        PacketCodec { codec }
-    }
-}
-
-impl Decoder for PacketCodec {
-    type Item = packets::In;
-    type Error = PacketDecodeError;
-    fn decode(&mut self, bs: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
-        let mut buf = &bs[..];
-        let orig_len = buf.len();
-        let res = self.codec.decode(&mut buf);
-        let final_len = buf.len();
-        bs.advance(orig_len - final_len);
-        match res {
-            Ok(v) => Ok(Some(value::from_value(&v)?)),
-            Err(value::decoder::Error::Eof) => Ok(None),
-            Err(e) => Err(PacketDecodeError::Read(e)),
-        }
-    }
-}
-
-impl Encoder for PacketCodec {
-    type Item = packets::Out;
-    type Error = PacketEncodeError;
-    fn encode(&mut self, item: Self::Item, bs: &mut BytesMut) -> Result<(), Self::Error> {
-        let v: V = value::to_value(&item)?;
-        bs.extend(self.codec.encode_bytes(&v)?);
-        Ok(())
-    }
-}
+pub type V = value::ArcValue;
 
 fn err(s: &str) -> packets::Out {
     packets::Out::Err(s.into())
@@ -152,13 +28,13 @@ struct Peer {
     id: ConnId,
     tx: UnboundedSender<packets::Out>,
     rx: UnboundedReceiver<packets::Out>,
-    frames: Framed<TcpStream, PacketCodec>,
+    frames: Framed<TcpStream, packets::Codec>,
 }
 
 impl Peer {
     async fn new(id: ConnId, stream: TcpStream) -> Self {
         let (tx, rx) = unbounded_channel();
-        let frames = Framed::new(stream, PacketCodec::new(value::Codec::new({
+        let frames = Framed::new(stream, packets::Codec::new(value::Codec::new({
             let mut m = Map::new();
             m.insert(0, value::Value::symbol("Discard"));
             m.insert(1, value::Value::symbol("Capture"));
@@ -168,7 +44,7 @@ impl Peer {
         Peer{ id, tx, rx, frames }
     }
 
-    async fn run(&mut self, spaces: Arc<Mutex<Map<V, ()>>>) -> Result<(), io::Error> {
+    async fn run(&mut self, spaces: Arc<Mutex<Map<V, ()>>>) -> Result<(), std::io::Error> {
         println!("{:?}: got {:?}", self.id, &self.frames.get_ref());
 
         let firstpacket = self.frames.next().await;
@@ -220,13 +96,13 @@ impl Peer {
                                 }
                             }
                         }
-                        Err(PacketDecodeError::Read(value::decoder::Error::Eof)) => running = false,
-                        Err(PacketDecodeError::Read(value::decoder::Error::Io(e))) => return Err(e),
-                        Err(PacketDecodeError::Read(value::decoder::Error::Syntax(s))) => {
+                        Err(packets::DecodeError::Read(value::decoder::Error::Eof)) => running = false,
+                        Err(packets::DecodeError::Read(value::decoder::Error::Io(e))) => return Err(e),
+                        Err(packets::DecodeError::Read(value::decoder::Error::Syntax(s))) => {
                             to_send.push(err(s));
                             running = false;
                         }
-                        Err(PacketDecodeError::Parse(e)) => {
+                        Err(packets::DecodeError::Parse(e)) => {
                             to_send.push(err(&format!("Packet deserialization error: {:?}", e)));
                             running = false;
                         }
diff --git a/src/packets.rs b/src/packets.rs
new file mode 100644
index 0000000..91a19eb
--- /dev/null
+++ b/src/packets.rs
@@ -0,0 +1,129 @@
+use super::V;
+
+use bytes::BytesMut;
+use preserves::value;
+use std::io;
+
+pub type EndpointName = V;
+pub type Assertion = V;
+pub type Captures = Vec<Assertion>;
+
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
+pub enum Action {
+    Assert(EndpointName, Assertion),
+    Clear(EndpointName),
+    Message(Assertion),
+}
+
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub enum Event {
+    Add(EndpointName, Captures),
+    Del(EndpointName, Captures),
+    Msg(EndpointName, Captures),
+    End(EndpointName),
+}
+
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
+pub enum In {
+    Connect(V),
+    Turn(Vec<Action>),
+    Ping(),
+    Pong(),
+}
+
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub enum Out {
+    Err(String),
+    Turn(Vec<Event>),
+    Ping(),
+    Pong(),
+}
+
+//---------------------------------------------------------------------------
+
+#[derive(Debug)]
+pub enum DecodeError {
+    Read(value::decoder::Error),
+    Parse(value::error::Error),
+}
+
+impl From<io::Error> for DecodeError {
+    fn from(v: io::Error) -> Self {
+        DecodeError::Read(v.into())
+    }
+}
+
+impl From<value::error::Error> for DecodeError {
+    fn from(v: value::error::Error) -> Self {
+        DecodeError::Parse(v)
+    }
+}
+
+//---------------------------------------------------------------------------
+
+#[derive(Debug)]
+pub enum EncodeError {
+    Write(value::encoder::Error),
+    Unparse(value::error::Error),
+}
+
+impl From<io::Error> for EncodeError {
+    fn from(v: io::Error) -> Self {
+        EncodeError::Write(v.into())
+    }
+}
+
+impl From<value::error::Error> for EncodeError {
+    fn from(v: value::error::Error) -> Self {
+        EncodeError::Unparse(v)
+    }
+}
+
+impl From<EncodeError> for io::Error {
+    fn from(v: EncodeError) -> Self {
+        match v {
+            EncodeError::Write(e) => e,
+            EncodeError::Unparse(e) =>
+                Self::new(io::ErrorKind::InvalidData, format!("{:?}", e)),
+        }
+    }
+}
+
+//---------------------------------------------------------------------------
+
+pub struct Codec {
+    codec: value::Codec<V>,
+}
+
+impl Codec {
+    pub fn new(codec: value::Codec<V>) -> Self {
+        Codec { codec }
+    }
+}
+
+impl tokio::codec::Decoder for Codec {
+    type Item = In;
+    type Error = DecodeError;
+    fn decode(&mut self, bs: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
+        let mut buf = &bs[..];
+        let orig_len = buf.len();
+        let res = self.codec.decode(&mut buf);
+        let final_len = buf.len();
+        bs.advance(orig_len - final_len);
+        match res {
+            Ok(v) => Ok(Some(value::from_value(&v)?)),
+            Err(value::decoder::Error::Eof) => Ok(None),
+            Err(e) => Err(DecodeError::Read(e)),
+        }
+    }
+}
+
+impl tokio::codec::Encoder for Codec {
+    type Item = Out;
+    type Error = EncodeError;
+    fn encode(&mut self, item: Self::Item, bs: &mut BytesMut) -> Result<(), Self::Error> {
+        let v: V = value::to_value(&item)?;
+        bs.extend(self.codec.encode_bytes(&v)?);
+        Ok(())
+    }
+}