unbound/pythonmod/examples/calc.py

82 lines
3.3 KiB
Python

# -*- coding: utf-8 -*-
'''
calc.py: DNS-based calculator
Copyright (c) 2009, Zdenek Vasicek (vasicek AT fit.vutbr.cz)
Marek Vavrusa (xvavru00 AT stud.fit.vutbr.cz)
This software is open source.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of the organization nor the names of its
contributors may be used to endorse or promote products derived from this
software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
'''
#Try: dig @localhost 1*25._calc_.cz.
def init(id, cfg): return True
def deinit(id): return True
def inform_super(id, qstate, superqstate, qdata): return True
def operate(id, event, qstate, qdata):
if (event == MODULE_EVENT_NEW) or (event == MODULE_EVENT_PASS):
if qstate.qinfo.qname_str.endswith("._calc_.cz.") and not ("__" in qstate.qinfo.qname_str):
try:
# the second and third argument to eval attempt to restrict
# functions and variables available to stop code execution
# but it may not be safe either. This is why __ substrings
# are excluded from evaluation.
res = eval(''.join(qstate.qinfo.qname_list[0:-3]),{"__builtins__":None},{})
except:
res = "exception"
msg = DNSMessage(qstate.qinfo.qname_str, RR_TYPE_TXT, RR_CLASS_IN, PKT_QR | PKT_RA | PKT_AA) #, 300)
msg.answer.append("%s 300 IN TXT \"%s\"" % (qstate.qinfo.qname_str,res))
if not msg.set_return_msg(qstate):
qstate.ext_state[id] = MODULE_ERROR
return True
qstate.return_rcode = RCODE_NOERROR
qstate.ext_state[id] = MODULE_FINISHED
return True
else:
#Pass on the unknown query to the iterator
qstate.ext_state[id] = MODULE_WAIT_MODULE
return True
elif event == MODULE_EVENT_MODDONE:
#the iterator has finished
qstate.ext_state[id] = MODULE_FINISHED
return True
log_err("pythonmod: Unknown event")
qstate.ext_state[id] = MODULE_ERROR
return True