agent: xrcp implementation for connection via link (no multicast) (#884)

* WIP: start working on connection invites

startSession/OOB is broken now - the port isn't coming from the actualy assigned one.

* Add invite types

* clean old invite-related types

* apply renames

* Move SessionKeys from Invitation

* Stub host-side keys and handle

* move keys and handles to Types

* add Simplex.RemoteControl.Client

* more keys

* progress

* crypto for sessions

* progress to multicast

* multicast crypto

* add RC TLS server

* agent api for remote control

* WIP: tls client

* fix test

* update encoding to include nonce

* add TODO

* update

* Use network-info to find TransportHost

* request and submit tls client certificate

* WIP: add missing bits for testing RC client

* RCEncryptedHello encoding

* add block encoding

* refactor

* validate known host certificate

* remove some spaghetti

* functional API to host/ctrl clients

* refactor connectRCCtrl_

* refactor connectRCHost

* question

* add type

* fix RC session

* update doc

* update doc 2

* add block on confirmation

* remove unused parameter

* export CtrlSessKeys

* export

* fix parsing

* move test of xrcp handshake

* move KEM to HELLO step

* fix JSON

* type

---------

Co-authored-by: Evgeny Poberezkin <2769109+epoberezkin@users.noreply.github.com>

src/Simplex/Messaging/Encoding.hs

@@ -11,6 +11,7 @@ module Simplex.Messaging.Encoding
   ( Encoding (..),
     Tail (..),
     Large (..),
+    _smpP,
     smpEncodeList,
     smpListP,
     lenEncode,
@@ -143,6 +144,9 @@ instance Encoding SystemTime where
   smpP = MkSystemTime <$> smpP <*> pure 0
   {-# INLINE smpP #-}
 
+_smpP :: Encoding a => Parser a
+_smpP = A.space *> smpP
+
 -- lists encode/parse as a sequence of items prefixed with list length (as 1 byte)
 smpEncodeList :: Encoding a => [a] -> ByteString
 smpEncodeList xs = B.cons (lenEncode $ length xs) . B.concat $ map smpEncode xs