HGKeeper

#!/usr/bin/env python

# -*- coding: utf-8 -*-

# This file is part of Beremiz IDE

# See COPYING file for copyrights details.

"""

The TLS-PSK adapter that handles SSL connections instead of regular sockets,

but using Pre Shared Keys instead of Certificates

Corresponding stunnel.conf on PLC side:

[ERPCPSK]

accept = 4000

connect = 127.0.0.1:3000

ciphers = PSK

sslVersion = TLSv1.2

PSKsecrets = psk.txt

"""

import socket

import ssl

try:

import sslpsk

except ImportError as e:

sslpsk = None

from erpc.transport import TCPTransport

class SSLPSKClientTransport(TCPTransport):

def __init__(self, host, port, psk):

""" overrides TCPTransport's __init__ to wrap socket in SSl wrapper """

super(TCPTransport, self).__init__()

self._host = host

self._port = port

self._sock = None

self._isServer = False

if sslpsk is None:

raise ImportError("sslpsk module is not available")

self.sslpskctx = sslpsk.SSLPSKContext(ssl.PROTOCOL_TLSv1_2)

self.sslpskctx.set_ciphers('PSK')

self.sslpskctx.psk = psk

raw_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

raw_sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1)

raw_sock.connect((self._host, self._port))

self._sock = self.sslpskctx.wrap_socket(raw_sock, server_side=False)