import getopt
import re
import socket
import sys
import time
from . import simplesock, select, errors, logger
PROTOCAL_RE = re.compile('^[a-z0-9]+://')
KNOWN_SCHEMES = {
# schema: (udp, ipv6, port); None = unchanged
'tcp': (False, None, None),
'tcp4': (False, False, None),
'tcp6': (False, True, None),
'udp': (True, None, None),
'udp4': (True, False, None),
'udp6': (True, True, None),
'http': (False, None, 80),
'https': (False, None, 443),
'dns': (True, None, 53),
'ftp': (False, None, 20),
'ssh': (False, None, 22),
'smtp': (False, None, 25),
}
from urllib.parse import urlparse
def _is_ipv6_addr(addr):
try:
socket.inet_pton(socket.AF_INET6, addr)
except socket.error:
return False
else:
return True
class Netcat:
"""
This is the main class you will use to interact with a peer over the
network! You may instanciate this class to either connect to a server,
listen for a one-off client, or wrap an existing sock/pipe/whatever.
One of the following must be passed in order to initialize a Netcat
object:
:param connect: the address/port to connect to
:param listen: the address/port to bind to for listening
:param sock: a python socket, pipe, file, etc to wrap
For ``connect`` and ``listen``, they accept basically any argument format
known to mankind. If you find an input format you think would be useful but
isn't accepted, let me know :P
Additionally, the following options modify the behavior of the object:
:param sock_send: If this is specified, this Netcat object will act
as a multiplexer/demultiplexer, using the "normal"
channel for receiving and this channel for sending.
This should be specified as a python socket or pipe
object.
.. warning:: Using ``sock_send`` will cause issues if
you pass this object into a context which
expects to be able to use its
``.fileno()``.
:param udp: Set to True to use udp connections when using the
connect or listen parameters
:param ipv6: Force using ipv6 when using the connect or listen
parameters
:param retry: The number of times to retry establishing a connection
after a short (200ms) sleep if it fails.
:param raise_timeout:
Whether to raise a `NetcatTimeout` exception when a
timeout is received. The default is to return any
buffered data and set ``self.timed_out`` = True
:param raise_eof: Whether to raise a `NetcatEOF` exception when EOF
is encountered. The default is to return any buffered
data and set ``self.eof = True``
:param loggers: A list of `Logger` objects to consume socket events
for logging.
The following options can be used to configure default loggers:
:param log_send: Pass a file-like object open for writing and all
data sent over the socket will be written to it.
:param log_recv: Pass a file-like object open for writing and all
data recieved from the socket will be written to it.
:param verbose: Set to True to cause a log of socket activity to be
written to stderr.
:param echo_headers:
Controls whether stderr logging should print headers
describing network operations and exceptional
conditions.
:param echo_perline:
Controls whether stderr logging should treat newlines
as record separators.
:param echo_hex: Controls whether stderr logging should produce a
hexdump.
:param echo_send_prefix:
A prefix to print to stderr before each logged line of
sent data.
:param echo_recv_prefix:
A prefix to print to stderr before each logged line of
received data.
:param log_yield: Control when logging messages are generated on
recv. By default, logging is done when data is
received from the socket, and may be buffered.
By setting this to True, logging is done when data
is yielded to the user, either directly from the
socket or from a buffer. This affects both stderr
and tee logging.
Any data that is extracted from the target address will override the
options specified here. For example, a url with the ``http://`` scheme
will go over tcp and port 80.
*Example 1:* Send a greeting to a UDP server listening at 192.168.3.6:8888
and wait for a response. Log the conversation to stderr as hex.
>>> nc = nclib.Netcat(('192.168.3.6', 8888),
... udp=True, verbose=True, echo_hex=True)
======= Connected to ('localhost', 8888) =======
>>> nc.send(b'\\x00\\x0dHello, world!')
======= Sending 15 bytes =======
>> 000000 00 0D 48 65 6C 6C 6F 2C 20 77 6F 72 6C 64 21 |..Hello, world! |
>>> response = nc.recv()
======= Receiving at most 4096 bytes =======
<< 000000 00 57 68 65 6C 6C 6F 20 66 72 69 65 6E 64 2E 20 |.Whello friend. |
<< 000010 74 69 6D 65 20 69 73 20 73 68 6F 72 74 2E 20 70 |time is short. p|
<< 000020 6C 65 61 73 65 20 74 6F 20 6E 6F 74 20 77 6F 72 |lease to not wor|
<< 000030 72 79 2C 20 79 6F 75 20 77 69 6C 6C 20 66 69 6E |ry, you will fin|
<< 000040 64 20 79 6F 75 72 20 77 61 79 2E 20 62 75 74 20 |d your way. but |
<< 000050 64 6F 20 68 75 72 72 79 2E |do hurry. |
>>> nc.send(b'\\x00\\x08oh no D:')
======= Sending 10 bytes =======
>> 00000F 00 | .|
>> 000010 08 6F 68 20 6E 6F 20 44 3A |.oh no D: |
*Example 2:* Listen for a local TCP connection on port 1234, allow the user
to interact with the client. Log the entire interaction to log.txt.
>>> logfile = open('log.txt', 'wb')
>>> nc = nclib.Netcat(listen=('localhost', 1234), log_send=logfile, log_recv=logfile)
>>> nc.interact()
"""
#
# Initializer functions
#
def __init__(self, connect=None, sock=None, listen=None,
sock_send=None, server=None,
udp=False, ipv6=False,
raise_timeout=False, raise_eof=False,
retry=0,
loggers=None,
# canned options
verbose=0,
log_send=None, log_recv=None, log_yield=False,
echo_headers=True, echo_perline=True, echo_hex=False,
echo_send_prefix='>> ', echo_recv_prefix='<< ',
):
# handle canned logger options
if loggers is None:
loggers = []
if verbose:
l = logger.StandardLogger(
_xwrap(sys.stderr),
log_yield=log_yield,
show_headers=echo_headers,
hex_dump=echo_hex,
split_newlines=echo_perline,
send_prefix=echo_send_prefix,
recv_prefix=echo_recv_prefix)
loggers.append(l)
if log_send is not None or log_recv is not None:
l = logger.TeeLogger(
log_send=_xwrap(log_send),
log_recv=_xwrap(log_recv),
log_yield=log_yield)
loggers.append(l)
# set properties
self.logger = logger.ManyLogger(loggers)
self.buf = b''
self.sock = None
self.peer = None
self.timed_out = False # set when an operation times out
self.eof = False
self._raise_timeout = raise_timeout
self._raise_eof = raise_eof
# handle several "convenient" args-passing cases
# case: Netcat(host, port)
if isinstance(connect, str) and isinstance(listen, int):
connect = (connect, listen)
# case: Netcat(sock)
if hasattr(connect, 'read') or hasattr(connect, 'recv'):
sock = connect
connect = None
# server= as alias for connect=
if server is not None:
connect = server
# sanity checks
if sock is None and listen is None and connect is None:
raise ValueError('Not enough arguments, need at least an '
'address or a socket or a listening address!')
if listen is not None and connect is not None:
raise ValueError("connect and listen arguments cannot be provided at the same time")
# three cases: 1) already have a sock 2) need to do a connect 3) need to do a listen
if sock is None:
if listen is not None:
target = listen
listen = True
else:
target = connect
listen = False
target, listen, udp, ipv6 = self._parse_target(target, listen, udp, ipv6)
self._connect(target, listen, udp, ipv6, int(retry))
else:
self.sock = sock
self.peer = connect
# extract the timeout from the sock before we wrap it in the simplesock
try:
self._timeout = self.sock.gettimeout()
except AttributeError:
self._timeout = None
# do simplesock wrapping and take sock_send into account
self.sock = _xwrap(self.sock)
if sock_send is not None:
self.sock = simplesock.SimpleDuplex(self.sock, _xwrap(sock_send))
@staticmethod
def _parse_target(target, listen, udp, ipv6):
"""
Takes the basic version of the user args and extract as much data as
possible from target. Returns a tuple that is its arguments but
sanitized.
"""
if isinstance(target, str):
if target.startswith('nc '):
out_host = None
out_port = None
try:
opts, pieces = getopt.getopt(target.split()[1:], 'u46lp:',
[])
except getopt.GetoptError as exc:
raise ValueError(exc)
for opt, arg in opts:
if opt == '-u':
udp = True
elif opt == '-4':
ipv6 = False
elif opt == '-6':
ipv6 = True
elif opt == '-l':
listen = True
elif opt == '-p':
out_port = int(arg)
else:
assert False, "unhandled option"
if not pieces:
pass
elif len(pieces) == 1:
if listen and pieces[0].isdigit():
out_port = int(pieces[0])
else:
out_host = pieces[0]
elif len(pieces) == 2 and pieces[1].isdigit():
out_host = pieces[0]
out_port = int(pieces[1])
else:
raise ValueError("Bad cmdline: %s" % target)
if out_host is None:
if listen:
out_host = '::' if ipv6 else '0.0.0.0'
else:
raise ValueError("Missing address: %s" % target)
if out_port is None:
raise ValueError("Missing port: %s" % target)
if _is_ipv6_addr(out_host):
ipv6 = True
return (out_host, out_port), listen, udp, ipv6
elif PROTOCAL_RE.match(target) is not None:
parsed = urlparse(target)
port = None
try:
scheme_udp, scheme_ipv6, scheme_port = KNOWN_SCHEMES[parsed.scheme]
except KeyError:
raise ValueError("Unknown scheme: %s" % parsed.scheme)
if scheme_udp is not None:
udp = scheme_udp
if scheme_ipv6 is not None:
ipv6 = scheme_ipv6
if scheme_port is not None:
port = scheme_port
if parsed.netloc.startswith('['):
addr, extra = parsed.netloc[1:].split(']', 1)
if extra.startswith(':'):
port = int(extra[1:])
else:
if ':' in parsed.netloc:
addr, port = parsed.netloc.split(':', 1)
port = int(port)
else:
addr = parsed.netloc
if addr is None or port is None:
raise ValueError("Can't parse addr/port from %s" % target)
if _is_ipv6_addr(addr):
ipv6 = True
return (addr, port), listen, udp, ipv6
else:
if target.startswith('['):
addr, extra = target[1:].split(']', 1)
if extra.startswith(':'):
port = int(extra[1:])
else:
port = None
else:
if ':' in target:
addr, port = target.split(':', 1)
port = int(port)
else:
addr = target
port = None
if port is None:
raise ValueError("No port given: %s" % target)
if _is_ipv6_addr(addr):
ipv6 = True
return (addr, port), listen, udp, ipv6
elif isinstance(target, int):
if listen:
out_port = target
else:
raise ValueError("Can't deal with number as connection address")
return ('::' if ipv6 else '0.0.0.0', out_port), listen, udp, ipv6
elif isinstance(target, tuple):
if len(target) >= 1 and isinstance(target[0], str) and _is_ipv6_addr(target[0]):
ipv6 = True
return target, listen, udp, ipv6
else:
raise ValueError("Can't parse target: %r" % target)
def _connect(self, target, listen, udp, ipv6, retry):
"""
Takes target/listen/udp/ipv6 and sets self.sock and self.peer
"""
ty = socket.SOCK_DGRAM if udp else socket.SOCK_STREAM
fam = socket.AF_INET6 if ipv6 else socket.AF_INET
self.sock = socket.socket(fam, ty)
if listen:
self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.sock.bind(target)
if not udp:
self.sock.listen(1)
conn, addr = self.sock.accept()
self.sock.close()
self.sock = conn
self.peer = addr
else:
self.buf, self.peer = self.sock.recvfrom(4096)
self.sock.connect(self.peer)
self.logger.buffering(self.buf)
else:
while retry >= 0:
try:
self.sock.connect(target)
except (socket.gaierror, socket.herror) as exc:
raise errors.NetcatError('Could not connect to %r: %r' \
% (target, exc))
except socket.error as exc:
if retry:
time.sleep(0.2)
retry -= 1
else:
raise errors.NetcatError('Could not connect to %r: %r' \
% (target, exc))
else:
break
self.peer = target
self.logger.connected(self.peer)
def add_logger(self, l):
"""
Add the given logger to the list of current loggers
"""
self.logger.children.append(l)
def remove_logger(self, l):
"""
Remove the given logger from the list of current loggers
"""
self.logger.children.remove(l)
#
# Socket metadata functionality
#
def close(self):
"""
Close the socket.
"""
return self.sock.close()
# inconsistent between sockets and files. support both
@property
def closed(self):
"""
Whether the socket has been closed by the user (not the peer).
"""
return self.sock.closed
@property
def _closed(self):
return self.closed
def shutdown(self, how=socket.SHUT_RDWR):
"""
Send a shutdown signal for one or both of reading and writing. Valid
arguments are ``socket.SHUT_RDWR``, ``socket.SHUT_RD``, and
``socket.SHUT_WR``.
Shutdown differs from closing in that it explicitly changes the state of
the socket resource to closed, whereas closing will only decrement the
number of peers on this end of the socket, since sockets can be a
resource shared by multiple peers on a single OS. When the number of
peers reaches zero, the socket is closed, but not deallocated, so you
still need to call close. (except that this is python and close is
automatically called on the deletion of the socket)
http://stackoverflow.com/questions/409783/socket-shutdown-vs-socket-close
"""
return self.sock.shutdown(how)
def shutdown_rd(self):
"""
Send a shutdown signal for reading - you may no longer read from this
socket.
"""
return self.shutdown(socket.SHUT_RD)
def shutdown_wr(self):
"""
Send a shutdown signal for writing - you may no longer write to this
socket.
"""
return self.shutdown(socket.SHUT_WR)
def fileno(self):
"""
Return the file descriptor associated with this socket
"""
return self.sock.fileno()
def settimeout(self, timeout):
"""
Set the default timeout in seconds to use for subsequent socket
operations. Set to None to wait forever, or 0 to be effectively
nonblocking.
"""
self._timeout = timeout
def gettimeout(self):
"""
Retrieve the timeout currently associated with the socket
"""
return self._timeout
def flush(self):
# no output buffering
pass
def _prep_select(self):
return self.sock._prep_select()
#
# Core socket data functionality
#
def _send(self, data):
ret = self.sock.send(data)
self.logger.sending(data[:ret])
return ret
def _recv(self, size, timeout=None):
"""
one-shot recv with timeout.
all timeouts are expressed via raising errors.NetcatTimeout
we wait until data is ready and then recv.
TODO: this is not thread safe...
"""
if timeout is not None:
r, _, _ = select.select([self.sock], timeout=timeout) # pylint: disable=no-member
if not r:
raise errors.NetcatTimeout
try:
data = self.sock.recv(size)
except ConnectionResetError:
data = b''
self.logger.buffering(data)
return data
def _recv_predicate(self, predicate, timeout, raise_eof=None):
"""
this is the core function which ties together all the nclib features
it will buffer data and call the predicate function on the buffer
until it returns a positive integer: the amount to unbuffer.
"""
if timeout is None:
deadline = None
else:
deadline = time.time() + timeout
self.timed_out = False
if raise_eof is None:
raise_eof = self._raise_eof
try:
first_shot = True
while True:
# step 1: check if the needed data is buffered.
# if so set cut_at and break out
cut_at = predicate(self.buf)
if cut_at > 0:
break
# step 2: calculate timeout for this read.
# if it's elapsed, raise error
if deadline is not None:
timeout = deadline - time.time()
if timeout < 0:
if first_shot:
timeout = 0
else:
raise errors.NetcatTimeout
first_shot = False
# step 3: receive a chunk with timeout and buffer it
data = self._recv(4096, timeout)
self.buf += data
# step 4: handle EOF. raise_eof=False should mean return the
# rest of the buffer regardless of predicate
if not data:
self.eof = True
self.logger.eofed()
if raise_eof:
raise errors.NetcatEOF("Connection dropped!")
cut_at = len(self.buf)
break
else:
self.eof = False
# handle interrupt
except KeyboardInterrupt:
self.logger.interrupted()
raise
# handle timeout. needs to be done this way since recv may raise
# timeout too
except errors.NetcatTimeout:
self.timed_out = True
if self._raise_timeout:
raise
cut_at = len(self.buf)
# handle arbitrary socket errors. should this be moved inward?
except socket.error as e:
raise errors.NetcatError('Socket error') from e
# unbuffer whatever we need to return
ret = self.buf[:cut_at]
self.buf = self.buf[cut_at:]
self.logger.unbuffering(ret)
return ret
#
# Public socket data functions
#
def _fixup_timeout(self, timeout='default'):
if timeout == 'default':
return self._timeout
return timeout
def recv(self, n=4096, timeout='default'):
"""
Receive at most n bytes (default 4096) from the socket
Aliases: read, get
"""
timeout = self._fixup_timeout(timeout)
self.logger.requesting_recv(n, timeout)
return self._recv_predicate(lambda s: min(n, len(s)), timeout)
def recv_until(self, s, max_size=None, timeout='default'):
"""
Recieve data from the socket until the given substring is observed.
Data in the same datagram as the substring, following the substring,
will not be returned and will be cached for future receives.
Aliases: read_until, readuntil, recvuntil
"""
if type(s) is str:
s = s.encode()
timeout = self._fixup_timeout(timeout)
self.logger.requesting_recv_until(s, max_size, timeout)
if max_size is None:
max_size = 2 ** 62
def _predicate(buf):
try:
return min(buf.index(s) + len(s), max_size)
except ValueError:
return 0 if len(buf) < max_size else max_size
return self._recv_predicate(_predicate, timeout)
def recv_all(self, timeout='default'):
"""
Return all data recieved until connection closes.
Aliases: read_all, readall, recvall
"""
timeout = self._fixup_timeout(timeout)
self.logger.requesting_recv_all(timeout)
return self._recv_predicate(lambda s: 0, timeout, raise_eof=False)
def recv_exactly(self, n, timeout='default'):
"""
Recieve exactly n bytes
Aliases: read_exactly, readexactly, recvexactly
"""
timeout = self._fixup_timeout(timeout)
self.logger.requesting_recv_exactly(n, timeout)
return self._recv_predicate(lambda s: n if len(s) >= n else 0, timeout)
def send(self, s):
"""
Sends all the given data to the socket.
Aliases: write, put, sendall, send_all
"""
if type(s) is str:
s = s.encode()
self.logger.requesting_send(s)
out = len(s)
while s:
s = s[self._send(s):]
return out
def interact(self, insock=sys.stdin, outsock=sys.stdout):
"""
Connects the socket to the terminal for user interaction.
Alternate input and output files may be specified.
This method cannot be used with a timeout.
Aliases: interactive, interaction
"""
self.logger.interact_starting()
other = Netcat(simplesock.SimpleDuplex(_xwrap(insock), _xwrap(outsock)))
ferry(self, other, suppress_timeout=True, suppress_raise_eof=True)
self.logger.interact_ending()
#
# Public socket data functionality
# (implemented with other public socket data functions)
#
LINE_ENDING = b'\n'
def recv_line(self, max_size=None, timeout='default', ending=None):
"""
Recieve until the next newline , default "\\n". The newline string can
be changed by changing ``nc.LINE_ENDING``. The newline will be returned
as part of the string.
Aliases: recvline, readline, read_line, readln, recvln
"""
if ending is None:
ending = self.LINE_ENDING
return self.recv_until(ending, max_size, timeout)
def send_line(self, line, ending=None):
"""
Write the string to the wire, followed by a newline. The newline string
can be changed by changing ``nc.LINE_ENDING``.
Aliases: sendline, writeline, write_line, writeln, sendln
"""
if ending is None:
ending = self.LINE_ENDING
return self.send(line + ending)
#
# Aliases :D
#
read = recv
get = recv
write = send
put = send
sendall = send
send_all = send
read_until = recv_until
readuntil = recv_until
recvuntil = recv_until
read_all = recv_all
readall = recv_all
recvall = recv_all
read_exactly = recv_exactly
readexactly = recv_exactly
recvexactly = recv_exactly
interactive = interact
ineraction = interact
recvline = recv_line
readline = recv_line
read_line = recv_line
readln = recv_line
recvln = recv_line
sendline = send_line
writeline = send_line
write_line = send_line
writeln = send_line
sendln = send_line
def merge(children, **kwargs):
"""
Return a Netcat object which whose receives will be the merged stream of
all the given children sockets.
:param children: A list of socks of any kind to receive from
:param kwargs: Any additional keyword arguments will be passed on to
the Netcat constructor. Notably, you might want to
specify `sock_send`, since by default you will not
be able to send data to a merged socket.
"""
nice_children = [_xwrap(child) for child in children]
return Netcat(simplesock.SimpleMerge(nice_children), **kwargs)
def _xwrap(sock):
"""
like simplesock.wrap but will also *unwrap* Netcat objects into their
constituent sockets. be warned that this will discard buffers
"""
return sock.sock if isinstance(sock, Netcat) else simplesock.wrap(sock)
def ferry(left, right, ferry_left=True, ferry_right=True,
suppress_timeout=True, suppress_raise_eof=False):
"""
Establish a linkage between two socks, automatically copying any data
that becomes available between the two.
:param left: A netcat sock
:param right: Another netcat sock
:param ferry_left: Whether to copy data leftward, i.e. from the
right sock to the left sock
:param ferry_right: Whether to copy data rightward, i.e. from the
left sock to the right sock
:param suppress_timeout: Whether to automatically set the socks'
timeout property to None and then reset it at
the end
:param suppress_raise_eof: Whether to automatically set the socks'
raise_eof property to None and then reset it at
the end
"""
left_timeout = left._timeout
left_raise_eof = left._raise_eof
right_timeout = right._timeout
right_raise_eof = right._raise_eof
selectable = []
if ferry_left:
selectable.append(right)
if ferry_right:
selectable.append(left)
if not selectable:
return
try:
if suppress_timeout:
left._timeout = None
right._timeout = None
if suppress_raise_eof:
left._raise_eof = False
right._raise_eof = False
while True:
r, _, _ = select.select(selectable) # pylint: disable=no-member
for readable in r:
data = readable.recv()
if not data:
raise errors.NetcatEOF
if readable is left:
right.send(data)
else:
left.send(data)
except (KeyboardInterrupt, errors.NetcatEOF):
pass
finally:
if suppress_timeout:
left._timeout = left_timeout
right._timeout = right_timeout
if suppress_raise_eof:
left._raise_eof = left_raise_eof
right._raise_eof = right_raise_eof
# congrats, you've found the secret in-progress command-line python netcat! it barely works.
#def add_arg(arg, options, args):
# if arg in ('v',):
# options['verbose'] += 1
# elif arg in ('l',):
# options['listen'] = True
# elif arg in ('k',):
# options['listenmore'] = True
# else:
# raise NetcatError('Bad argument: %s' % arg)
#
#def usage(verbose=False):
# print """Usage: %s [-vlk] hostname port""" % sys.argv[0]
# if verbose:
# print """More help coming soon :)"""
#
#def main(*args_list):
# args = iter(args_list)
# args.next()
# hostname = None
# port = None
# options = {'verbose': False, 'listen': False, 'listenmore': False}
# for arg in args:
# if arg.startswith('--'):
# add_arg(arg, options, args)
# elif arg.startswith('-'):
# for argchar in arg[1:]:
# add_arg(argchar, options, args)
# else:
# if arg.isdigit():
# if port is not None:
# if hostname is not None:
# usage()
# raise NetcatError('Already specified hostname and port: %s' % arg)
# hostname = port # on the off chance the host is totally numeric :P
# port = int(arg)
# else:
# if hostname is not None:
# usage()
# raise NetcatError('Already specified hostname: %s' % arg)
# hostname = arg
# if port is None:
# usage()
# raise NetcatError('No port specified!')
# if options['listen']:
# hostname = '0.0.0.0' if hostname is None else hostname
# while True:
# Netcat(listen=(hostname, port), verbose=options['verbose']).interact()
# if not options['listenmore']:
# break
# else:
# if hostname is None:
# usage()
# raise NetcatError('No hostname specified!')
# Netcat(server=(hostname, port), verbose=options['verbose']).interact()
#
#
#if __name__ == '__main__':
# main(*sys.argv)
