add parameters for session resuming

mostly callbacks during the handshake, and a parameter to enable session usage.

Network/TLS/Context.hs

@@ -74,10 +74,15 @@ data TLSParams = TLSParams
 	, pWantClientCert    :: Bool                -- ^ request a certificate from client.
 	                                            -- use by server only.
 	, pUseSecureRenegotiation :: Bool           -- notify that we want to use secure renegotation
+	, pUseSession             :: Bool           -- generate new session if specified
 	, pCertificates      :: [(X509, Maybe PrivateKey)] -- ^ the cert chain for this context with the associated keys if any.
 	, pLogging           :: TLSLogging          -- ^ callback for logging
 	, onHandshake        :: Measurement -> IO Bool -- ^ callback on a beggining of handshake
 	, onCertificatesRecv :: [X509] -> IO TLSCertificateUsage -- ^ callback to verify received cert chain.
+	, onSessionResumption :: SessionID -> IO (Maybe SessionData) -- ^ callback to maybe resume session on server.
+	, onSessionEstablished :: SessionID -> SessionData -> IO ()  -- ^ callback when session have been established
+	, onSessionInvalidated :: SessionID -> IO ()                 -- ^ callback when session is invalidated by error
+	, sessionResumeWith   :: Maybe (SessionID, SessionData) -- ^ try to establish a connection using this session.
 	}
 
 defaultLogging :: TLSLogging
@@ -96,10 +101,15 @@ defaultParams = TLSParams
 	, pCompressions           = [nullCompression]
 	, pWantClientCert         = False
 	, pUseSecureRenegotiation = True
+	, pUseSession             = True
 	, pCertificates           = []
 	, pLogging                = defaultLogging
 	, onHandshake             = (\_ -> return True)
 	, onCertificatesRecv      = (\_ -> return CertificateUsageAccept)
+	, onSessionResumption     = (\_ -> return Nothing)
+	, onSessionEstablished    = (\_ _ -> return ())
+	, onSessionInvalidated    = (\_ -> return ())
+	, sessionResumeWith       = Nothing
 	}
 
 instance Show TLSParams where