def handle_session(self):
Logger.debug(7, 'Session loop running')
self.incoming_message('<?xml version="1.0" encoding="UTF-8"?><hello xmlns="parrot"/>')
while True:
try:
Logger.debug(5,'NETCONF server ready, waiting for next message')
msg = self.read_msg()
except EOFError:
Logger.debug(5,'EOF -- end of session')
return
except Exception as e:
verdict = self.handle_read_exception(e)
if verdict == "kill-session":
return
if verdict == "kill-server":
Logger.info('Server terminating')
sys.exit(1)
# Else keep going
try:
if("" == msg):
Logger.debug(5,'EOF ++ end of session')
return
if self.incoming_message(msg) == True:
return
except Exception as e:
Logger.error('Exception in server processing: ' + str(e))
def process_instructions(self, reply_msg):
def split_processing_instructions(reply_msg):
instructions = []
pi_start_marker = '<?parrot '
pi_end_marker = '?>'
while True:
pi_start = reply_msg.find(pi_start_marker)
if pi_start < 0:
break
pi_end = reply_msg[pi_start:].find(pi_end_marker)
if pi_end < 0:
return ('bad-processing-instruction', reply_msg[pi_start:pi_start+20])
pi = reply_msg[pi_start+len(pi_start_marker):pi_end]
if pi_start:
instructions += [('send', reply_msg[:pi_start])]
reply_msg = reply_msg[pi_end+len(pi_end_marker):]
cmd = pi.split(" ")[0]
data = pi[len(cmd)+1:]
instructions += [(cmd, data)]
if reply_msg:
instructions += [('send', reply_msg)]
if not instructions:
instructions = [('empty-response', None)]
return instructions
instructions = split_processing_instructions(reply_msg)
end_session = False
for (cmd, data) in instructions:
if cmd == "send":
Logger.debug(6, f'Sending {len(data)} bytes', payload=data)
self.send_message(data)
elif cmd == "ignore":
Logger.debug(5, f'Not sending any response')
elif cmd == "netconf11":
Logger.debug(5, f'Switching to NETCONF 1.1')
self.choose_netconf_ver([11])
elif cmd == "netconf10":
Logger.debug(5, f'Switching to NETCONF 1.0')
self.choose_netconf_ver([10])
elif cmd == "empty-response":
Logger.warning(f'Template did not provide any response. Ending the session.')
end_session = True
elif cmd == "end-session":
Logger.info(f'Ending session')
end_session = True
else:
Logger.error(f'Unknown processing instruction "{cmd}" in template. Ending the session.')
end_session = True
return end_session
def start_subsystem(self, name, transport, channel):
Logger.debug(
8,
f'NETCONFsubsys: start_subsystem name={name} transport={transport} channel={channel}'
)
self.sock = channel
Logger.debug(9,
'Started NETCONF server on channel {!r}'.format(channel))
try:
self.handle_session()
except Exception as e:
Logger.error(f'NETCONFsubsys: callback exception {e}')
##raise
Logger.debug(8,
'Stopped NETCONF server on channel {!r}'.format(channel))
def handle_connection(self, host_key):
try:
DoGSSAPIKeyExchange = False
t = Transport(self.sock, gss_kex=DoGSSAPIKeyExchange)
t.set_subsystem_handler('netconf', self.subsys)
t.set_gss_host(socket.getfqdn(""))
try:
t.load_server_moduli()
except:
Logger.warning('Failed to load moduli -- gex will be unsupported.')
t.add_server_key(host_key)
server = Server()
t.start_server(server=server)
# wait for auth
self.channel = t.accept(20)
if self.channel is None:
Logger.error('No SSH channel')
return
Logger.info('Waiting for message')
server.event.wait(10)
Logger.info('Closing')
##self.channel.close()
Logger.info('Client connection closed')
except ConnectionResetError as e:
Logger.debug(5,'Connection reset by peer')
except SSHException:
Logger.error('SSH negotiation failed, client connection dropped')
except Exception as e:
Logger.error('Caught exception: ' + str(e.__class__) + ': ' + str(e))
traceback.print_exc()
try:
t.close()
except:
pass