468 lines
16 KiB
Python
Executable file
468 lines
16 KiB
Python
Executable file
# This file is part of Scapy
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# See http://www.secdev.org/projects/scapy for more information
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# Copyright (C) Philippe Biondi <phil@secdev.org>
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# This program is published under a GPLv2 license
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"""
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SuperSocket.
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"""
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from __future__ import absolute_import
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from select import select, error as select_error
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import ctypes
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import errno
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import os
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import socket
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import struct
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import time
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from scapy.config import conf
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from scapy.consts import LINUX, DARWIN, WINDOWS
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from scapy.data import MTU, ETH_P_IP, SOL_PACKET, SO_TIMESTAMPNS
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from scapy.compat import raw, bytes_encode
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from scapy.error import warning, log_runtime
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import scapy.modules.six as six
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import scapy.packet
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from scapy.utils import PcapReader, tcpdump
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# Utils
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class _SuperSocket_metaclass(type):
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def __repr__(self):
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if self.desc is not None:
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return "<%s: %s>" % (self.__name__, self.desc)
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else:
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return "<%s>" % self.__name__
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# Used to get ancillary data
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PACKET_AUXDATA = 8
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ETH_P_8021Q = 0x8100
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TP_STATUS_VLAN_VALID = 1 << 4
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class tpacket_auxdata(ctypes.Structure):
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_fields_ = [
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("tp_status", ctypes.c_uint),
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("tp_len", ctypes.c_uint),
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("tp_snaplen", ctypes.c_uint),
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("tp_mac", ctypes.c_ushort),
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("tp_net", ctypes.c_ushort),
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("tp_vlan_tci", ctypes.c_ushort),
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("tp_padding", ctypes.c_ushort),
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]
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# SuperSocket
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class SuperSocket(six.with_metaclass(_SuperSocket_metaclass)):
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desc = None
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closed = 0
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nonblocking_socket = False
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read_allowed_exceptions = ()
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auxdata_available = False
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def __init__(self, family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0): # noqa: E501
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self.ins = socket.socket(family, type, proto)
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self.outs = self.ins
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self.promisc = None
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def send(self, x):
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sx = raw(x)
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try:
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x.sent_time = time.time()
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except AttributeError:
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pass
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return self.outs.send(sx)
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if six.PY2:
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def _recv_raw(self, sock, x):
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"""Internal function to receive a Packet"""
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pkt, sa_ll = sock.recvfrom(x)
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return pkt, sa_ll, None
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else:
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def _recv_raw(self, sock, x):
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"""Internal function to receive a Packet,
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and process ancillary data.
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"""
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timestamp = None
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if not self.auxdata_available:
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pkt, _, _, sa_ll = sock.recvmsg(x)
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return pkt, sa_ll, timestamp
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flags_len = socket.CMSG_LEN(4096)
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pkt, ancdata, flags, sa_ll = sock.recvmsg(x, flags_len)
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if not pkt:
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return pkt, sa_ll, timestamp
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for cmsg_lvl, cmsg_type, cmsg_data in ancdata:
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# Check available ancillary data
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if (cmsg_lvl == SOL_PACKET and cmsg_type == PACKET_AUXDATA):
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# Parse AUXDATA
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try:
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auxdata = tpacket_auxdata.from_buffer_copy(cmsg_data)
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except ValueError:
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# Note: according to Python documentation, recvmsg()
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# can return a truncated message. A ValueError
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# exception likely indicates that Auxiliary
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# Data is not supported by the Linux kernel.
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return pkt, sa_ll, timestamp
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if auxdata.tp_vlan_tci != 0 or \
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auxdata.tp_status & TP_STATUS_VLAN_VALID:
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# Insert VLAN tag
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tag = struct.pack(
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"!HH",
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ETH_P_8021Q,
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auxdata.tp_vlan_tci
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)
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pkt = pkt[:12] + tag + pkt[12:]
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elif cmsg_lvl == socket.SOL_SOCKET and \
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cmsg_type == SO_TIMESTAMPNS:
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length = len(cmsg_data)
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if length == 16: # __kernel_timespec
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tmp = struct.unpack("ll", cmsg_data)
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elif length == 8: # timespec
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tmp = struct.unpack("ii", cmsg_data)
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else:
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log_runtime.warning("Unknown timespec format.. ?!")
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continue
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timestamp = tmp[0] + tmp[1] * 1e-9
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return pkt, sa_ll, timestamp
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def recv_raw(self, x=MTU):
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"""Returns a tuple containing (cls, pkt_data, time)"""
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return conf.raw_layer, self.ins.recv(x), None
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def recv(self, x=MTU):
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cls, val, ts = self.recv_raw(x)
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if not val or not cls:
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return
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try:
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pkt = cls(val)
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except KeyboardInterrupt:
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raise
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except Exception:
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if conf.debug_dissector:
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from scapy.sendrecv import debug
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debug.crashed_on = (cls, val)
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raise
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pkt = conf.raw_layer(val)
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if ts:
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pkt.time = ts
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return pkt
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def fileno(self):
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return self.ins.fileno()
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def close(self):
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if self.closed:
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return
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self.closed = True
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if getattr(self, "outs", None):
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if getattr(self, "ins", None) != self.outs:
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if WINDOWS or self.outs.fileno() != -1:
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self.outs.close()
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if getattr(self, "ins", None):
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if WINDOWS or self.ins.fileno() != -1:
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self.ins.close()
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def sr(self, *args, **kargs):
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from scapy import sendrecv
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return sendrecv.sndrcv(self, *args, **kargs)
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def sr1(self, *args, **kargs):
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from scapy import sendrecv
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a, b = sendrecv.sndrcv(self, *args, **kargs)
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if len(a) > 0:
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return a[0][1]
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else:
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return None
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def sniff(self, *args, **kargs):
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from scapy import sendrecv
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return sendrecv.sniff(opened_socket=self, *args, **kargs)
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def tshark(self, *args, **kargs):
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from scapy import sendrecv
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return sendrecv.tshark(opened_socket=self, *args, **kargs)
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@staticmethod
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def select(sockets, remain=conf.recv_poll_rate):
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"""This function is called during sendrecv() routine to select
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the available sockets.
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:param sockets: an array of sockets that need to be selected
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:returns: an array of sockets that were selected and
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the function to be called next to get the packets (i.g. recv)
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"""
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try:
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inp, _, _ = select(sockets, [], [], remain)
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except (IOError, select_error) as exc:
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# select.error has no .errno attribute
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if not exc.args or exc.args[0] != errno.EINTR:
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raise
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return inp, None
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def __del__(self):
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"""Close the socket"""
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self.close()
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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"""Close the socket"""
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self.close()
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class L3RawSocket(SuperSocket):
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desc = "Layer 3 using Raw sockets (PF_INET/SOCK_RAW)"
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def __init__(self, type=ETH_P_IP, filter=None, iface=None, promisc=None, nofilter=0): # noqa: E501
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self.outs = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW) # noqa: E501
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self.outs.setsockopt(socket.SOL_IP, socket.IP_HDRINCL, 1)
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self.ins = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(type)) # noqa: E501
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self.iface = iface
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if iface is not None:
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self.ins.bind((self.iface, type))
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if not six.PY2:
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try:
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# Receive Auxiliary Data (VLAN tags)
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self.ins.setsockopt(SOL_PACKET, PACKET_AUXDATA, 1)
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self.ins.setsockopt(
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socket.SOL_SOCKET,
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SO_TIMESTAMPNS,
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1
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)
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self.auxdata_available = True
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except OSError:
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# Note: Auxiliary Data is only supported since
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# Linux 2.6.21
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msg = "Your Linux Kernel does not support Auxiliary Data!"
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log_runtime.info(msg)
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def recv(self, x=MTU):
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pkt, sa_ll, ts = self._recv_raw(self.ins, x)
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if sa_ll[2] == socket.PACKET_OUTGOING:
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return None
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if sa_ll[3] in conf.l2types:
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cls = conf.l2types[sa_ll[3]]
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lvl = 2
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elif sa_ll[1] in conf.l3types:
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cls = conf.l3types[sa_ll[1]]
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lvl = 3
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else:
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cls = conf.default_l2
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warning("Unable to guess type (interface=%s protocol=%#x family=%i). Using %s", sa_ll[0], sa_ll[1], sa_ll[3], cls.name) # noqa: E501
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lvl = 3
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try:
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pkt = cls(pkt)
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except KeyboardInterrupt:
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raise
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except Exception:
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if conf.debug_dissector:
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raise
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pkt = conf.raw_layer(pkt)
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if lvl == 2:
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pkt = pkt.payload
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if pkt is not None:
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if ts is None:
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from scapy.arch import get_last_packet_timestamp
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ts = get_last_packet_timestamp(self.ins)
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pkt.time = ts
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return pkt
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def send(self, x):
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try:
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sx = raw(x)
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x.sent_time = time.time()
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return self.outs.sendto(sx, (x.dst, 0))
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except socket.error as msg:
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log_runtime.error(msg)
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class SimpleSocket(SuperSocket):
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desc = "wrapper around a classic socket"
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def __init__(self, sock):
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self.ins = sock
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self.outs = sock
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class StreamSocket(SimpleSocket):
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desc = "transforms a stream socket into a layer 2"
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nonblocking_socket = True
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def __init__(self, sock, basecls=None):
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if basecls is None:
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basecls = conf.raw_layer
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SimpleSocket.__init__(self, sock)
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self.basecls = basecls
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def recv(self, x=MTU):
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pkt = self.ins.recv(x, socket.MSG_PEEK)
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x = len(pkt)
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if x == 0:
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return None
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pkt = self.basecls(pkt)
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pad = pkt.getlayer(conf.padding_layer)
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if pad is not None and pad.underlayer is not None:
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del(pad.underlayer.payload)
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from scapy.packet import NoPayload
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while pad is not None and not isinstance(pad, NoPayload):
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x -= len(pad.load)
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pad = pad.payload
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self.ins.recv(x)
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return pkt
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class SSLStreamSocket(StreamSocket):
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desc = "similar usage than StreamSocket but specialized for handling SSL-wrapped sockets" # noqa: E501
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def __init__(self, sock, basecls=None):
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self._buf = b""
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super(SSLStreamSocket, self).__init__(sock, basecls)
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# 65535, the default value of x is the maximum length of a TLS record
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def recv(self, x=65535):
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pkt = None
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if self._buf != b"":
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try:
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pkt = self.basecls(self._buf)
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except Exception:
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# We assume that the exception is generated by a buffer underflow # noqa: E501
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pass
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if not pkt:
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buf = self.ins.recv(x)
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if len(buf) == 0:
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raise socket.error((100, "Underlying stream socket tore down"))
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self._buf += buf
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x = len(self._buf)
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pkt = self.basecls(self._buf)
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pad = pkt.getlayer(conf.padding_layer)
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if pad is not None and pad.underlayer is not None:
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del(pad.underlayer.payload)
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while pad is not None and not isinstance(pad, scapy.packet.NoPayload):
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x -= len(pad.load)
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pad = pad.payload
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self._buf = self._buf[x:]
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return pkt
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class L2ListenTcpdump(SuperSocket):
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desc = "read packets at layer 2 using tcpdump"
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def __init__(self, iface=None, promisc=None, filter=None, nofilter=False,
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prog=None, *arg, **karg):
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self.outs = None
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args = ['-w', '-', '-s', '65535']
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if iface is None and (WINDOWS or DARWIN):
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iface = conf.iface
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if WINDOWS:
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try:
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iface = iface.pcap_name
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except AttributeError:
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pass
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self.iface = iface
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if iface is not None:
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args.extend(['-i', self.iface])
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if not promisc:
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args.append('-p')
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if not nofilter:
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if conf.except_filter:
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if filter:
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filter = "(%s) and not (%s)" % (filter, conf.except_filter)
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else:
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filter = "not (%s)" % conf.except_filter
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if filter is not None:
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args.append(filter)
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self.tcpdump_proc = tcpdump(None, prog=prog, args=args, getproc=True)
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self.ins = PcapReader(self.tcpdump_proc.stdout)
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def recv(self, x=MTU):
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return self.ins.recv(x)
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def close(self):
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SuperSocket.close(self)
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self.tcpdump_proc.kill()
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@staticmethod
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def select(sockets, remain=None):
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if (WINDOWS or DARWIN):
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return sockets, None
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return SuperSocket.select(sockets, remain=remain)
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class TunTapInterface(SuperSocket):
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"""A socket to act as the host's peer of a tun / tap interface.
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"""
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desc = "Act as the host's peer of a tun / tap interface"
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def __init__(self, iface=None, mode_tun=None, *arg, **karg):
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self.iface = conf.iface if iface is None else iface
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self.mode_tun = ("tun" in self.iface) if mode_tun is None else mode_tun
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self.closed = True
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self.open()
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def open(self):
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"""Open the TUN or TAP device."""
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if not self.closed:
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return
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self.outs = self.ins = open(
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"/dev/net/tun" if LINUX else ("/dev/%s" % self.iface), "r+b",
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buffering=0
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)
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if LINUX:
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from fcntl import ioctl
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# TUNSETIFF = 0x400454ca
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# IFF_TUN = 0x0001
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# IFF_TAP = 0x0002
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# IFF_NO_PI = 0x1000
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ioctl(self.ins, 0x400454ca, struct.pack(
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"16sH", bytes_encode(self.iface),
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0x0001 if self.mode_tun else 0x1002,
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))
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self.closed = False
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def __call__(self, *arg, **karg):
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"""Needed when using an instantiated TunTapInterface object for
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conf.L2listen, conf.L2socket or conf.L3socket.
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"""
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return self
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def recv(self, x=MTU):
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if self.mode_tun:
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data = os.read(self.ins.fileno(), x + 4)
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proto = struct.unpack('!H', data[2:4])[0]
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return conf.l3types.get(proto, conf.raw_layer)(data[4:])
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return conf.l2types.get(1, conf.raw_layer)(
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os.read(self.ins.fileno(), x)
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)
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def send(self, x):
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sx = raw(x)
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if self.mode_tun:
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try:
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proto = conf.l3types[type(x)]
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except KeyError:
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log_runtime.warning(
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"Cannot find layer 3 protocol value to send %s in "
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"conf.l3types, using 0",
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x.name if hasattr(x, "name") else type(x).__name__
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)
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proto = 0
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sx = struct.pack('!HH', 0, proto) + sx
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try:
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try:
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x.sent_time = time.time()
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except AttributeError:
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pass
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return os.write(self.outs.fileno(), sx)
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except socket.error:
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log_runtime.error("%s send", self.__class__.__name__, exc_info=True) # noqa: E501
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