diff --git a/docs/code_structure.org b/docs/code_structure.org
index 1efc68dcd..51952c731 100644
--- a/docs/code_structure.org
+++ b/docs/code_structure.org
@@ -7,6 +7,7 @@
 **** self signed router descriptor
 *** Crypto key types
 
+
 ** network / threading / sync utilities
 *** threadpool
 *** logic (single thread threadpool)
@@ -15,7 +16,6 @@
 *** ini parser
 *** llarp::Configuration
 
-
 ** cryptography
 *** llarp::Crypto interface
 **** libsodium / sntrup implementation
@@ -45,12 +45,14 @@
 **** distinctly identified by the union of interface and direction
 **** Holds many ILinkSessions bound on the distinctly idenitfied direction/interface
 
+
 ** link layer messages
 *** link layer message parser
 **** parses buffers as bencoded dicts
 *** link layer message handler
 **** handles each type of link layer message
 
+
 ** IHopHandler
 *** llarp::PathHopConfig
 **** txid, rxid, shared secret at hop
@@ -62,24 +64,28 @@
 **** has txid, rxid, shared secret, hash of shared secret
 
 
-
 ** pathset
 *** path::Builder
 **** builds and maintains a set of paths for a common use
 
+
 ** routing layer message router
 *** routing::IMessageHandler
 **** interface for routing layer message processing
 **** transit hops implement this if they are an endpoint 
 **** path::Path implement this always
 
+
 ** dht "layer" / rc gossiper
+*** TODO rewrite/refactor
+
 ** hidden service data structures
 *** IntroSet
 **** decrypted plaintext hidden service descriptor
 *** EncryptedIntroSet
 **** public encrpyted / signed version of IntroSet 
 
+
 ** service endpoint / outbound context connectivitybackend
 *** service::Endpoint
 **** backend for sending/recieving packets over the hidden service protocol layer
@@ -89,14 +95,23 @@
 *** service::OutboundContext
 **** implements SendContext extends path::Builder and path::PathSet
 **** for maintaining a pathset that aligns on an introset's intros
+~
 
-** snode / exit session management
-*** exit::Session
-  
 ** snode / exit connectivity backend
+*** exit::BaseSession
+**** extends path::Builder
+**** obtains an exit/snode session from the router they are aligning to
+*** exit::Endpoint
+**** snode/exit side of an exit::Session
 
 ** snapp / exit / mobile / null frontend handlers
+*** handlers::TunEndpoint
+**** extends service::Endpoint
+**** provides tun interface frontend for hidden service backend
+*** handlers::ExitEndpoint
+**** provides tun interface frontend for exit/snode backend
 
-** outbound message dispatcher
 
+** outbound message dispatcher
+*** TODO tom please document these