Issue #10141: socket: add SocketCAN (PF_CAN) support. Initial patch by Matthias

Fuchs, updated by Tiago Gonçalves.
This commit is contained in:
Charles-François Natali 2011-10-06 19:47:44 +02:00
parent 90c30e87be
commit 47413c1171
10 changed files with 683 additions and 321 deletions

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@ -80,6 +80,11 @@ Socket addresses are represented as follows:
If *addr_type* is TIPC_ADDR_ID, then *v1* is the node, *v2* is the
reference, and *v3* should be set to 0.
- A tuple ``(interface, )`` is used for the :const:`AF_CAN` address family,
where *interface* is a string representing a network interface name like
``'can0'``. The network interface name ``''`` can be used to receive packets
from all network interfaces of this family.
- Certain other address families (:const:`AF_BLUETOOTH`, :const:`AF_PACKET`)
support specific representations.
@ -216,6 +221,19 @@ The module :mod:`socket` exports the following constants and functions:
in the Unix header files are defined; for a few symbols, default values are
provided.
.. data:: AF_CAN
PF_CAN
SOL_CAN_*
CAN_*
Many constants of these forms, documented in the Linux documentation, are
also defined in the socket module.
Availability: Linux >= 2.6.25.
.. versionadded:: 3.3
.. data:: SIO_*
RCVALL_*
@ -387,10 +405,14 @@ The module :mod:`socket` exports the following constants and functions:
Create a new socket using the given address family, socket type and protocol
number. The address family should be :const:`AF_INET` (the default),
:const:`AF_INET6` or :const:`AF_UNIX`. The socket type should be
:const:`SOCK_STREAM` (the default), :const:`SOCK_DGRAM` or perhaps one of the
other ``SOCK_`` constants. The protocol number is usually zero and may be
omitted in that case.
:const:`AF_INET6`, :const:`AF_UNIX` or :const:`AF_CAN`. The socket type
should be :const:`SOCK_STREAM` (the default), :const:`SOCK_DGRAM`,
:const:`SOCK_RAW` or perhaps one of the other ``SOCK_`` constants. The
protocol number is usually zero and may be omitted in that case or
:const:`CAN_RAW` in case the address family is :const:`AF_CAN`.
.. versionchanged:: 3.3
The AF_CAN family was added.
.. function:: socketpair([family[, type[, proto]]])
@ -1213,7 +1235,7 @@ sends traffic to the first one connected successfully. ::
print('Received', repr(data))
The last example shows how to write a very simple network sniffer with raw
The next example shows how to write a very simple network sniffer with raw
sockets on Windows. The example requires administrator privileges to modify
the interface::
@ -1238,6 +1260,45 @@ the interface::
# disabled promiscuous mode
s.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)
The last example shows how to use the socket interface to communicate to a CAN
network. This example might require special priviledge::
import socket
import struct
# CAN frame packing/unpacking (see `struct can_frame` in <linux/can.h>)
can_frame_fmt = "=IB3x8s"
def build_can_frame(can_id, data):
can_dlc = len(data)
data = data.ljust(8, b'\x00')
return struct.pack(can_frame_fmt, can_id, can_dlc, data)
def dissect_can_frame(frame):
can_id, can_dlc, data = struct.unpack(can_frame_fmt, frame)
return (can_id, can_dlc, data[:can_dlc])
# create a raw socket and bind it to the `vcan0` interface
s = socket.socket(socket.AF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
s.bind(('vcan0',))
while True:
cf, addr = s.recvfrom(16)
print('Received: can_id=%x, can_dlc=%x, data=%s' % dissect_can_frame(cf))
try:
s.send(cf)
except socket.error:
print('Error sending CAN frame')
try:
s.send(build_can_frame(0x01, b'\x01\x02\x03'))
except socket.error:
print('Error sending CAN frame')
Running an example several times with too small delay between executions, could
lead to this error::

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@ -300,15 +300,22 @@ signal
socket
------
The :class:`~socket.socket` class now exposes addititonal methods to
process ancillary data when supported by the underlying platform:
* The :class:`~socket.socket` class now exposes additional methods to process
ancillary data when supported by the underlying platform:
* :func:`~socket.socket.sendmsg`
* :func:`~socket.socket.recvmsg`
* :func:`~socket.socket.recvmsg_into`
* :func:`~socket.socket.sendmsg`
* :func:`~socket.socket.recvmsg`
* :func:`~socket.socket.recvmsg_into`
(Contributed by David Watson in :issue:`6560`, based on an earlier patch by
Heiko Wundram)
* The :class:`~socket.socket` class now supports the PF_CAN protocol family
(http://en.wikipedia.org/wiki/Socketcan), on Linux
(http://lwn.net/Articles/253425).
(Contributed by Matthias Fuchs, updated by Tiago Gonçalves in :issue:`10141`)
(Contributed by David Watson in :issue:`6560`, based on an earlier patch
by Heiko Wundram)
ssl
---

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@ -21,6 +21,7 @@
import signal
import math
import pickle
import struct
try:
import fcntl
except ImportError:
@ -36,6 +37,18 @@
thread = None
threading = None
def _have_socket_can():
"""Check whether CAN sockets are supported on this host."""
try:
s = socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
except (AttributeError, socket.error, OSError):
return False
else:
s.close()
return True
HAVE_SOCKET_CAN = _have_socket_can()
# Size in bytes of the int type
SIZEOF_INT = array.array("i").itemsize
@ -80,6 +93,30 @@ def doCleanups(self, *args, **kwargs):
with self._cleanup_lock:
return super().doCleanups(*args, **kwargs)
class SocketCANTest(unittest.TestCase):
"""To be able to run this test, a `vcan0` CAN interface can be created with
the following commands:
# modprobe vcan
# ip link add dev vcan0 type vcan
# ifconfig vcan0 up
"""
interface = 'vcan0'
bufsize = 128
def setUp(self):
self.s = socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
try:
self.s.bind((self.interface,))
except socket.error:
self.skipTest('network interface `%s` does not exist' %
self.interface)
self.s.close()
def tearDown(self):
self.s.close()
self.s = None
class ThreadableTest:
"""Threadable Test class
@ -210,6 +247,26 @@ def clientTearDown(self):
self.cli = None
ThreadableTest.clientTearDown(self)
class ThreadedCANSocketTest(SocketCANTest, ThreadableTest):
def __init__(self, methodName='runTest'):
SocketCANTest.__init__(self, methodName=methodName)
ThreadableTest.__init__(self)
def clientSetUp(self):
self.cli = socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
try:
self.cli.bind((self.interface,))
except socket.error:
self.skipTest('network interface `%s` does not exist' %
self.interface)
self.cli.close()
def clientTearDown(self):
self.cli.close()
self.cli = None
ThreadableTest.clientTearDown(self)
class SocketConnectedTest(ThreadedTCPSocketTest):
"""Socket tests for client-server connection.
@ -1072,6 +1129,112 @@ def test_listen_backlog0(self):
srv.close()
@unittest.skipUnless(HAVE_SOCKET_CAN, 'SocketCan required for this test.')
class BasicCANTest(unittest.TestCase):
def testCrucialConstants(self):
socket.AF_CAN
socket.PF_CAN
socket.CAN_RAW
def testCreateSocket(self):
with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
pass
def testBindAny(self):
with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
s.bind(('', ))
def testTooLongInterfaceName(self):
# most systems limit IFNAMSIZ to 16, take 1024 to be sure
with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
self.assertRaisesRegexp(socket.error, 'interface name too long',
s.bind, ('x' * 1024,))
@unittest.skipUnless(hasattr(socket, "CAN_RAW_LOOPBACK"),
'socket.CAN_RAW_LOOPBACK required for this test.')
def testLoopback(self):
with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
for loopback in (0, 1):
s.setsockopt(socket.SOL_CAN_RAW, socket.CAN_RAW_LOOPBACK,
loopback)
self.assertEqual(loopback,
s.getsockopt(socket.SOL_CAN_RAW, socket.CAN_RAW_LOOPBACK))
@unittest.skipUnless(hasattr(socket, "CAN_RAW_FILTER"),
'socket.CAN_RAW_FILTER required for this test.')
def testFilter(self):
can_id, can_mask = 0x200, 0x700
can_filter = struct.pack("=II", can_id, can_mask)
with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
s.setsockopt(socket.SOL_CAN_RAW, socket.CAN_RAW_FILTER, can_filter)
self.assertEqual(can_filter,
s.getsockopt(socket.SOL_CAN_RAW, socket.CAN_RAW_FILTER, 8))
@unittest.skipUnless(HAVE_SOCKET_CAN, 'SocketCan required for this test.')
@unittest.skipUnless(thread, 'Threading required for this test.')
class CANTest(ThreadedCANSocketTest):
"""The CAN frame structure is defined in <linux/can.h>:
struct can_frame {
canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
__u8 can_dlc; /* data length code: 0 .. 8 */
__u8 data[8] __attribute__((aligned(8)));
};
"""
can_frame_fmt = "=IB3x8s"
def __init__(self, methodName='runTest'):
ThreadedCANSocketTest.__init__(self, methodName=methodName)
@classmethod
def build_can_frame(cls, can_id, data):
"""Build a CAN frame."""
can_dlc = len(data)
data = data.ljust(8, b'\x00')
return struct.pack(cls.can_frame_fmt, can_id, can_dlc, data)
@classmethod
def dissect_can_frame(cls, frame):
"""Dissect a CAN frame."""
can_id, can_dlc, data = struct.unpack(cls.can_frame_fmt, frame)
return (can_id, can_dlc, data[:can_dlc])
def testSendFrame(self):
cf, addr = self.s.recvfrom(self.bufsize)
self.assertEqual(self.cf, cf)
self.assertEqual(addr[0], self.interface)
self.assertEqual(addr[1], socket.AF_CAN)
def _testSendFrame(self):
self.cf = self.build_can_frame(0x00, b'\x01\x02\x03\x04\x05')
self.cli.send(self.cf)
def testSendMaxFrame(self):
cf, addr = self.s.recvfrom(self.bufsize)
self.assertEqual(self.cf, cf)
def _testSendMaxFrame(self):
self.cf = self.build_can_frame(0x00, b'\x07' * 8)
self.cli.send(self.cf)
def testSendMultiFrames(self):
cf, addr = self.s.recvfrom(self.bufsize)
self.assertEqual(self.cf1, cf)
cf, addr = self.s.recvfrom(self.bufsize)
self.assertEqual(self.cf2, cf)
def _testSendMultiFrames(self):
self.cf1 = self.build_can_frame(0x07, b'\x44\x33\x22\x11')
self.cli.send(self.cf1)
self.cf2 = self.build_can_frame(0x12, b'\x99\x22\x33')
self.cli.send(self.cf2)
@unittest.skipUnless(thread, 'Threading required for this test.')
class BasicTCPTest(SocketConnectedTest):
@ -4194,6 +4357,7 @@ def test_main():
if isTipcAvailable():
tests.append(TIPCTest)
tests.append(TIPCThreadableTest)
tests.extend([BasicCANTest, CANTest])
tests.extend([
CmsgMacroTests,
SendmsgUDPTest,

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@ -319,6 +319,7 @@ John Fouhy
Martin Franklin
Robin Friedrich
Ivan Frohne
Matthias Fuchs
Jim Fulton
Tadayoshi Funaba
Gyro Funch
@ -354,6 +355,7 @@ Michael Gilfix
Yannick Gingras
Christoph Gohlke
Tim Golden
Tiago Gonçalves
Chris Gonnerman
David Goodger
Hans de Graaff

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@ -1322,6 +1322,9 @@ Tools/Demos
Extension Modules
-----------------
- Issue #10141: socket: Add SocketCAN (PF_CAN) support. Initial patch by
Matthias Fuchs, updated by Tiago Gonçalves.
- Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle
would be finalized after the reference to its underlying BufferedRWPair's
writer got cleared by the GC.

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@ -1220,6 +1220,25 @@ makesockaddr(SOCKET_T sockfd, struct sockaddr *addr, size_t addrlen, int proto)
}
#endif
#ifdef HAVE_LINUX_CAN_H
case AF_CAN:
{
struct sockaddr_can *a = (struct sockaddr_can *)addr;
char *ifname = "";
struct ifreq ifr;
/* need to look up interface name given index */
if (a->can_ifindex) {
ifr.ifr_ifindex = a->can_ifindex;
if (ioctl(sockfd, SIOCGIFNAME, &ifr) == 0)
ifname = ifr.ifr_name;
}
return Py_BuildValue("O&h", PyUnicode_DecodeFSDefault,
ifname,
a->can_family);
}
#endif
/* More cases here... */
default:
@ -1587,6 +1606,53 @@ getsockaddrarg(PySocketSockObject *s, PyObject *args,
}
#endif
#ifdef HAVE_LINUX_CAN_H
case AF_CAN:
switch (s->sock_proto) {
case CAN_RAW:
{
struct sockaddr_can *addr;
PyObject *interfaceName;
struct ifreq ifr;
addr = (struct sockaddr_can *)addr_ret;
Py_ssize_t len;
if (!PyArg_ParseTuple(args, "O&", PyUnicode_FSConverter,
&interfaceName))
return 0;
len = PyBytes_GET_SIZE(interfaceName);
if (len == 0) {
ifr.ifr_ifindex = 0;
} else if (len < sizeof(ifr.ifr_name)) {
strcpy(ifr.ifr_name, PyBytes_AS_STRING(interfaceName));
if (ioctl(s->sock_fd, SIOCGIFINDEX, &ifr) < 0) {
s->errorhandler();
Py_DECREF(interfaceName);
return 0;
}
} else {
PyErr_SetString(socket_error,
"AF_CAN interface name too long");
Py_DECREF(interfaceName);
return 0;
}
addr->can_family = AF_CAN;
addr->can_ifindex = ifr.ifr_ifindex;
*len_ret = sizeof(*addr);
Py_DECREF(interfaceName);
return 1;
}
default:
PyErr_SetString(socket_error,
"getsockaddrarg: unsupported CAN protocol");
return 0;
}
#endif
/* More cases here... */
default:
@ -1680,6 +1746,14 @@ getsockaddrlen(PySocketSockObject *s, socklen_t *len_ret)
}
#endif
#ifdef HAVE_LINUX_CAN_H
case AF_CAN:
{
*len_ret = sizeof (struct sockaddr_can);
return 1;
}
#endif
/* More cases here... */
default:
@ -5533,6 +5607,15 @@ PyInit__socket(void)
PyModule_AddStringConstant(m, "BDADDR_LOCAL", "00:00:00:FF:FF:FF");
#endif
#ifdef AF_CAN
/* Controller Area Network */
PyModule_AddIntConstant(m, "AF_CAN", AF_CAN);
#endif
#ifdef PF_CAN
/* Controller Area Network */
PyModule_AddIntConstant(m, "PF_CAN", PF_CAN);
#endif
#ifdef AF_PACKET
PyModule_AddIntMacro(m, AF_PACKET);
#endif
@ -5803,6 +5886,28 @@ PyInit__socket(void)
#else
PyModule_AddIntConstant(m, "SOL_UDP", 17);
#endif
#ifdef SOL_CAN_BASE
PyModule_AddIntConstant(m, "SOL_CAN_BASE", SOL_CAN_BASE);
#endif
#ifdef SOL_CAN_RAW
PyModule_AddIntConstant(m, "SOL_CAN_RAW", SOL_CAN_RAW);
PyModule_AddIntConstant(m, "CAN_RAW", CAN_RAW);
#endif
#ifdef HAVE_LINUX_CAN_H
PyModule_AddIntConstant(m, "CAN_EFF_FLAG", CAN_EFF_FLAG);
PyModule_AddIntConstant(m, "CAN_RTR_FLAG", CAN_RTR_FLAG);
PyModule_AddIntConstant(m, "CAN_ERR_FLAG", CAN_ERR_FLAG);
PyModule_AddIntConstant(m, "CAN_SFF_MASK", CAN_SFF_MASK);
PyModule_AddIntConstant(m, "CAN_EFF_MASK", CAN_EFF_MASK);
PyModule_AddIntConstant(m, "CAN_ERR_MASK", CAN_ERR_MASK);
#endif
#ifdef HAVE_LINUX_CAN_RAW_H
PyModule_AddIntConstant(m, "CAN_RAW_FILTER", CAN_RAW_FILTER);
PyModule_AddIntConstant(m, "CAN_RAW_ERR_FILTER", CAN_RAW_ERR_FILTER);
PyModule_AddIntConstant(m, "CAN_RAW_LOOPBACK", CAN_RAW_LOOPBACK);
PyModule_AddIntConstant(m, "CAN_RAW_RECV_OWN_MSGS", CAN_RAW_RECV_OWN_MSGS);
#endif
#ifdef IPPROTO_IP
PyModule_AddIntConstant(m, "IPPROTO_IP", IPPROTO_IP);
#else

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@ -72,6 +72,14 @@ typedef int socklen_t;
# include <linux/tipc.h>
#endif
#ifdef HAVE_LINUX_CAN_H
#include <linux/can.h>
#endif
#ifdef HAVE_LINUX_CAN_RAW_H
#include <linux/can/raw.h>
#endif
#ifndef Py__SOCKET_H
#define Py__SOCKET_H
#ifdef __cplusplus
@ -126,6 +134,9 @@ typedef union sock_addr {
#ifdef HAVE_NETPACKET_PACKET_H
struct sockaddr_ll ll;
#endif
#ifdef HAVE_LINUX_CAN_H
struct sockaddr_can can;
#endif
} sock_addr_t;
/* The object holding a socket. It holds some extra information,

614
configure vendored

File diff suppressed because it is too large Load diff

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@ -1376,6 +1376,13 @@ AC_CHECK_HEADERS(linux/netlink.h,,,[
#endif
])
# On Linux, can.h and can/raw.h require sys/socket.h
AC_CHECK_HEADERS(linux/can.h linux/can/raw.h,,,[
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
])
# checks for typedefs
was_it_defined=no
AC_MSG_CHECKING(for clock_t in time.h)

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@ -467,6 +467,12 @@
/* Define to 1 if you have the `linkat' function. */
#undef HAVE_LINKAT
/* Define to 1 if you have the <linux/can.h> header file. */
#undef HAVE_LINUX_CAN_H
/* Define to 1 if you have the <linux/can/raw.h> header file. */
#undef HAVE_LINUX_CAN_RAW_H
/* Define to 1 if you have the <linux/netlink.h> header file. */
#undef HAVE_LINUX_NETLINK_H