124 lines
4.3 KiB
Python
124 lines
4.3 KiB
Python
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# 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) Nils Weiss <nils@we155.de>
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# This program is published under a GPLv2 license
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# scapy.contrib.description = Native CANSocket
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# scapy.contrib.status = loads
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"""
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NativeCANSocket.
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"""
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import struct
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import socket
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import time
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from scapy.config import conf
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from scapy.supersocket import SuperSocket
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from scapy.error import Scapy_Exception, warning
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from scapy.layers.can import CAN
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from scapy.packet import Padding
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from scapy.arch.linux import get_last_packet_timestamp
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conf.contribs['NativeCANSocket'] = {'channel': "can0"}
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CAN_FRAME_SIZE = 16
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CAN_INV_FILTER = 0x20000000
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class NativeCANSocket(SuperSocket):
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desc = "read/write packets at a given CAN interface using PF_CAN sockets"
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nonblocking_socket = True
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def __init__(self, channel=None, receive_own_messages=False,
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can_filters=None, remove_padding=True, basecls=CAN, **kwargs):
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bustype = kwargs.pop("bustype", None)
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if bustype and bustype != "socketcan":
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warning("You created a NativeCANSocket. "
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"If you're providing the argument 'bustype', please use "
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"the correct one to achieve compatibility with python-can"
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"/PythonCANSocket. \n'bustype=socketcan'")
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self.basecls = basecls
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self.remove_padding = remove_padding
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self.channel = conf.contribs['NativeCANSocket']['channel'] if \
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channel is None else channel
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self.ins = socket.socket(socket.PF_CAN,
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socket.SOCK_RAW,
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socket.CAN_RAW)
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try:
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self.ins.setsockopt(socket.SOL_CAN_RAW,
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socket.CAN_RAW_RECV_OWN_MSGS,
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struct.pack("i", receive_own_messages))
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except Exception as exception:
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raise Scapy_Exception(
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"Could not modify receive own messages (%s)", exception
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)
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if can_filters is None:
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can_filters = [{
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"can_id": 0,
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"can_mask": 0
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}]
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can_filter_fmt = "={}I".format(2 * len(can_filters))
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filter_data = []
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for can_filter in can_filters:
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filter_data.append(can_filter["can_id"])
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filter_data.append(can_filter["can_mask"])
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self.ins.setsockopt(socket.SOL_CAN_RAW,
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socket.CAN_RAW_FILTER,
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struct.pack(can_filter_fmt, *filter_data))
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self.ins.bind((self.channel,))
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self.outs = self.ins
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def recv(self, x=CAN_FRAME_SIZE):
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try:
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pkt, sa_ll = self.ins.recvfrom(x)
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except BlockingIOError: # noqa: F821
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warning("Captured no data, socket in non-blocking mode.")
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return None
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except socket.timeout:
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warning("Captured no data, socket read timed out.")
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return None
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except OSError:
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# something bad happened (e.g. the interface went down)
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warning("Captured no data.")
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return None
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# need to change the byte order of the first four bytes,
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# required by the underlying Linux SocketCAN frame format
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if not conf.contribs['CAN']['swap-bytes']:
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pkt = struct.pack("<I12s", *struct.unpack(">I12s", pkt))
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len = pkt[4]
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canpkt = self.basecls(pkt[:len + 8])
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canpkt.time = get_last_packet_timestamp(self.ins)
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if self.remove_padding:
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return canpkt
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else:
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return canpkt / Padding(pkt[len + 8:])
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def send(self, x):
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try:
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if hasattr(x, "sent_time"):
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x.sent_time = time.time()
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# need to change the byte order of the first four bytes,
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# required by the underlying Linux SocketCAN frame format
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bs = bytes(x)
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if not conf.contribs['CAN']['swap-bytes']:
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bs = bs + b'\x00' * (CAN_FRAME_SIZE - len(bs))
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bs = struct.pack("<I12s", *struct.unpack(">I12s", bs))
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return SuperSocket.send(self, bs)
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except socket.error as msg:
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raise msg
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def close(self):
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self.ins.close()
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CANSocket = NativeCANSocket
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