1 files changed, 46 insertions, 0 deletions

diff --git a/Connection.hs b/Connection.hs
index a7e5d4cc..9a4077f5 100644
--- a/Connection.hs
+++ b/Connection.hs
@@ -5,8 +5,11 @@ module Connection where
 import Control.Applicative
 import Control.Arrow
 import Control.Concurrent.STM
+import Data.Bits
+import Data.Word
 import qualified Data.Map as Map
          ;import Data.Map (Map)
+import Network.Socket (SockAddr(..))
 
 import PingMachine
 
@@ -34,6 +37,43 @@ data Connection status = Connection
     }
  deriving Functor
 
+-- | A 'PeerAddress' identifies an active session.  For inactive sessions, multiple
+-- values may be feasible.
+
+-- We use a 'SockAddr' as it is convenient for TCP and UDP connections.  But if
+-- that is not your use case, see 'uniqueAsKey'.
+newtype PeerAddress = PeerAddress { peerAddress :: SockAddr }
+    deriving (Eq,Ord,Show)
+
+-- | A 24-byte word.
+data Uniq24 = Uniq24 !Word64 !Word64 !Word64
+ deriving (Eq,Ord,Show)
+
+-- | Coerce a 'Uniq24' to a useable 'PeerAddress'.  Note that this stores the
+-- special value 0 into the port number of the underlying 'SockAddr' and thus
+-- should be compatible for mixing together with TCP/UDP peers.
+uniqueAsKey :: Uniq24 -> PeerAddress
+uniqueAsKey (Uniq24 x y z) = PeerAddress $ SockAddrInet6 (fromIntegral 0) a bcde f
+ where
+    a = fromIntegral (x `shiftR` 32)
+    b = fromIntegral x
+    c = fromIntegral (y `shiftR` 32)
+    d = fromIntegral y
+    e = fromIntegral (z `shiftR` 32)
+    f = fromIntegral z
+    bcde = (b,c,d,e)
+
+-- | Inverse of 'uniqueAsKey'
+keyAsUnique :: PeerAddress -> Maybe Uniq24
+keyAsUnique (PeerAddress (SockAddrInet6 0 a bcde f)) = Just $ Uniq24 x y z
+ where
+    (b,c,d,e) = bcde
+    x = (fromIntegral a `shiftL` 32) .|. fromIntegral b
+    y = (fromIntegral c `shiftL` 32) .|. fromIntegral d
+    z = (fromIntegral e `shiftL` 32) .|. fromIntegral f
+keyAsUniq _ = Nothing
+
+
 -- | This is an interface to make or query status information about connections
 -- of a specific kind.
 --
@@ -58,6 +98,12 @@ data Manager status k = Manager
     , showProgress :: status -> String
       -- | Show a connection key as a string.
     , showKey      :: k -> String
+      -- | Obtain an address from a human-friendly name.  For TCP/UDP
+      -- connections, this might be a forward-resolving DNS query.
+    , resolvePeer :: k -> IO [PeerAddress]
+      -- | This is the reverse of 'resolvePeer'.  For TCP/UDP connections, this
+      -- might be a reverse-resolve DNS query.
+    , reverseAddress :: PeerAddress -> IO [k]
     }
 
 -- | Present status information (visible in a UI) for a connection.