1# 2# SPDX-License-Identifier: BSD-2-Clause 3# 4# Copyright (c) 2017 Kristof Provost <kp@FreeBSD.org> 5# 6# Redistribution and use in source and binary forms, with or without 7# modification, are permitted provided that the following conditions 8# are met: 9# 1. Redistributions of source code must retain the above copyright 10# notice, this list of conditions and the following disclaimer. 11# 2. Redistributions in binary form must reproduce the above copyright 12# notice, this list of conditions and the following disclaimer in the 13# documentation and/or other materials provided with the distribution. 14# 15# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25# SUCH DAMAGE. 26# 27 28import threading 29import scapy.all as sp 30import sys 31 32class Sniffer(threading.Thread): 33 def __init__(self, args, check_function, recvif, timeout=3, defrag=False): 34 threading.Thread.__init__(self) 35 36 self._sem = threading.Semaphore(0) 37 self._args = args 38 self._timeout = timeout 39 self._recvif = recvif 40 self._check_function = check_function 41 self._defrag = defrag 42 self.correctPackets = 0 43 44 self.start() 45 if not self._sem.acquire(timeout=30): 46 raise Exception("Failed to start sniffer") 47 48 def _checkPacket(self, packet): 49 ret = self._check_function(self._args, packet) 50 if ret: 51 self.correctPackets += 1 52 return ret 53 54 def _startedCb(self): 55 self._sem.release() 56 57 def run(self): 58 self.packets = [] 59 # With fragment reassembly we can't stop the sniffer after catching 60 # the good packets, as those have not been reassembled. We must 61 # wait for sniffer to finish and check returned packets instead. 62 if self._defrag == 'IPv4': 63 self.packets = sp.sniff(session=sp.IPSession, iface=self._recvif, 64 timeout=self._timeout, started_callback=self._startedCb) 65 for p in self.packets: 66 self._checkPacket(p) 67 elif self._defrag == 'IPv6': 68 self.packets = sp.sniff(session=sp.DefaultSession, iface=self._recvif, 69 timeout=self._timeout, started_callback=self._startedCb) 70 for p in sp.defragment6(self.packets): 71 self._checkPacket(p) 72 else: 73 self.packets = sp.sniff(iface=self._recvif, 74 stop_filter=self._checkPacket, timeout=self._timeout, 75 started_callback=self._startedCb) 76