scapy.contrib.isotp¶

ISOTPSocket.

class scapy.contrib.isotp.ISOTP(*args, **kwargs)¶

Bases: scapy.packet.Packet

aliastypes¶

answers(other)¶

default_fields¶

static defragment(can_frames, use_extended_addressing=None)¶

direction¶

dst¶

exdst¶

explicit¶

exsrc¶

fields¶

fields_desc¶

ISOTP fields¶
data	`StrField`	`b''`

fieldtype¶

fragment()¶

name¶

original¶

overload_fields¶

overloaded_fields¶

packetfields¶

payload¶

post_transforms¶

raw_packet_cache¶

raw_packet_cache_fields¶

sent_time¶

sniffed_on¶

src¶

time¶

underlayer¶

validate_fields()¶

wirelen¶

class scapy.contrib.isotp.ISOTPHeader¶

Bases: scapy.layers.can.CAN

aliastypes¶

extract_padding(p)¶

fields_desc¶

ISOTPHeader fields¶
flags	`FlagsField` (3 bits)	`<Flag 0 ()>`
identifier	`XBitField` (29 bits)	`0`
length	`ByteField`	`None`
reserved	`ThreeBytesField`	`0`

guess_payload_class(payload)¶: ISOTP encodes the frame type in the first nibble of a frame.

post_build(pkt, pay)¶: This will set the ByteField ‘length’ to the correct value.

class scapy.contrib.isotp.ISOTPHeaderEA¶

Bases: scapy.contrib.isotp.ISOTPHeader

aliastypes¶

fields_desc¶

ISOTPHeaderEA fields¶
flags	`FlagsField` (3 bits)	`<Flag 0 ()>`
identifier	`XBitField` (29 bits)	`0`
length	`ByteField`	`None`
reserved	`ThreeBytesField`	`0`
extended_address	`XByteField`	`0`

post_build(p, pay)¶: This will set the ByteField ‘length’ to the correct value. ‘chb(len(pay) + 1)’ is required, because the field ‘extended_address’ is counted as payload on the CAN layer

class scapy.contrib.isotp.ISOTP_SF¶

Bases: scapy.packet.Packet

aliastypes¶

fields_desc¶

ISOTP_SF fields¶
type	`BitEnumField` (4 bits)	`0`
message_size	`BitFieldLenField` (4 bits)	`None`
data	`StrLenField`	`b''`

class scapy.contrib.isotp.ISOTP_FF¶

Bases: scapy.packet.Packet

aliastypes¶

fields_desc¶

ISOTP_FF fields¶
type	`BitEnumField` (4 bits)	`1`
message_size	`BitField` (12 bits)	`0`
extended_message_size	`BitField` (Cond) (32 bits)	`0`
data	`StrField`	`b''`

class scapy.contrib.isotp.ISOTP_CF¶

Bases: scapy.packet.Packet

aliastypes¶

fields_desc¶

ISOTP_CF fields¶
type	`BitEnumField` (4 bits)	`2`
index	`BitField` (4 bits)	`0`
data	`StrField`	`b''`

class scapy.contrib.isotp.ISOTP_FC¶

Bases: scapy.packet.Packet

aliastypes¶

fields_desc¶

ISOTP_FC fields¶
type	`BitEnumField` (4 bits)	`3`
fc_flag	`BitEnumField` (4 bits)	`0`
block_size	`ByteField`	`0`
separation_time	`ByteField`	`0`

class scapy.contrib.isotp.ISOTPSoftSocket(can_socket=None, sid=0, did=0, extended_addr=None, extended_rx_addr=None, rx_block_size=0, rx_separation_time_min=0, padding=False, listen_only=False, basecls=<class 'scapy.contrib.isotp.ISOTP'>)¶

Bases: scapy.supersocket.SuperSocket

This class is a wrapper around the ISOTPSocketImplementation, for the reasons described below.

The ISOTPSoftSocket aims to be fully compatible with the Linux ISOTP sockets provided by the can-isotp kernel module, while being usable on any operating system. Therefore, this socket needs to be able to respond to an incoming FF frame with a FC frame even before the recv() method is called. A thread is needed for receiving CAN frames in the background, and since the lower layer CAN implementation is not guaranteed to have a functioning POSIX select(), each ISOTP socket needs its own CAN receiver thread. Additionally, 2 timers are necessary to keep track of the timeouts and frame separation times, and each timer is implemented in its own thread. In total, each ISOTPSoftSocket spawns 3 background threads when constructed, which must be terminated afterwards by calling the close() method. SuperSocket automatically calls the close() method when the GC destroys an ISOTPSoftSocket. However, note that if any thread holds a reference to an ISOTPSoftSocket object, it will not be collected by the GC.

The implementation of the ISOTP protocol, along with the necessary threads, are stored in the ISOTPSocketImplementation class, and therefore:

There no reference from ISOTPSocketImplementation to ISOTPSoftSocket
ISOTPSoftSocket can be normally garbage collected
Upon destruction, ISOTPSoftSocket.close() will be called
ISOTPSoftSocket.close() will call ISOTPSocketImplementation.close()
All background threads can be stopped by the garbage collector

begin_send(p)¶: Begin the transmission of message p. This method returns after sending the first frame. If multiple frames are necessary to send the message, this socket will unable to send other messages until either the transmission of this frame succeeds or it fails.

close()¶

nonblocking_socket = True¶

recv(x=65535)¶

recv_raw(x=65535)¶: Receive a complete ISOTP message, blocking until a message is received or the specified timeout is reached. If self.timeout is 0, then this function doesn’t block and returns the first frame in the receive buffer or None if there isn’t any.

static select(sockets, remain=None)¶: This function is called during sendrecv() routine to wait for sockets to be ready to receive

class scapy.contrib.isotp.ISOTPSession(*args, **kwargs)¶

Bases: scapy.sessions.DefaultSession

Defragment ISOTP packets ‘on-the-flow’.

Usage: >>> sniff(session=ISOTPSession)

on_packet_received(pkt)¶

scapy.contrib.isotp.ISOTPSocket¶: alias of scapy.contrib.isotp.ISOTPSoftSocket

class scapy.contrib.isotp.ISOTPSocketImplementation(can_socket, src_id, dst_id, padding=False, extended_addr=None, extended_rx_addr=None, rx_block_size=0, rx_separation_time_min=0, listen_only=False)¶

Bases: scapy.automaton.SelectableObject

Implementation of an ISOTP “state machine”.

Most of the ISOTP logic was taken from https://github.com/hartkopp/can-isotp/blob/master/net/can/isotp.c

This class is separated from ISOTPSoftSocket to make sure the background threads can’t hold a reference to ISOTPSoftSocket, allowing it to be collected by the GC.

begin_send(x)¶: Begins sending an ISOTP message. This method does not block.

can_send(load)¶

check_recv()¶: Implementation for SelectableObject

close()¶

on_can_recv(p)¶

on_recv(cf)¶: Function that must be called every time a CAN frame is received, to advance the state machine.

recv(timeout=None)¶: Receive an ISOTP frame, blocking if none is available in the buffer for at most ‘timeout’ seconds.

send(p)¶: Send an ISOTP frame and block until the message is sent or an error happens.

class scapy.contrib.isotp.ISOTPMessageBuilder(use_ext_addr=None, did=None, basecls=None)¶

Bases: object

Utility class to build ISOTP messages out of CAN frames, used by both ISOTP.defragment() and ISOTPSession.

This class attempts to interpret some CAN frames as ISOTP frames, both with and without extended addressing at the same time. For example, if an extended address of 07 is being used, all frames will also be interpreted as ISOTP single-frame messages.

CAN frames are fed to an ISOTPMessageBuilder object with the feed() method and the resulting ISOTP frames can be extracted using the pop() method.

class Bucket(total_len, first_piece, ts=None)¶

Bases: object

push(piece)¶

property count¶: Returns the number of ready ISOTP messages built from the provided can frames

feed(can)¶: Attempt to feed an incoming CAN frame into the state machine

pop(identifier=None, ext_addr=None)¶

Returns a built ISOTP message

Parameters

identifier – if not None, only return isotp messages with this destination
ext_addr – if identifier is not None, only return isotp messages with this extended address for destination

Returns

an ISOTP packet, or None if no message is ready

scapy.contrib.isotp.ISOTPScan(sock, scan_range=range(0, 2048), extended_addressing=False, noise_listen_time=2, sniff_time=0.1, output_format=None, can_interface=None, extended_can_id=False, verbose=False)¶

Scan for ISOTP Sockets on a bus and return findings

Parameters

sock – CANSocket object to communicate with the bus under scan
scan_range – hexadecimal range of CAN-Identifiers to scan. Default is 0x0 - 0x7ff
extended_addressing – scan with ISOTP extended addressing
noise_listen_time – seconds to listen for default communication on the bus
sniff_time – time the scan waits for isotp flow control responses after sending a first frame
output_format – defines the format of the returned results (text, code or sockets). Provide a string e.g. “text”. Default is “socket”.
can_interface – interface used to create the returned code/sockets
extended_can_id – Use Extended CAN-Frames
verbose – displays information during scan

Scan for ISOTP Sockets in the defined range and returns found sockets in a specified format. The format can be:

text: human readable output
code: python code for copy&paste
sockets: if output format is not specified, ISOTPSockets will be created and returned in a list

class scapy.contrib.isotp.ISOTPNativeSocket(iface=None, sid=0, did=0, extended_addr=None, extended_rx_addr=None, listen_only=False, padding=False, transmit_time=100, basecls=<class 'scapy.contrib.isotp.ISOTP'>)¶

Bases: scapy.supersocket.SuperSocket

can_isotp_fc_options_fmt = '@3B'¶

can_isotp_ll_options_fmt = '@3B'¶

can_isotp_options_fmt = '@2I4B'¶

desc = 'read/write packets at a given CAN interface using CAN_ISOTP socket '¶

recv(x=65535)¶

recv_raw(x=65535)¶: Receives a packet, then returns a tuple containing (cls, pkt_data, time)

sockaddr_can_fmt = '@H3I'¶