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72 lines
2.0 KiB
Python
72 lines
2.0 KiB
Python
import os
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import socket
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import subprocess as ssubprocess
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from sshuttle.helpers import log, debug1, Fatal, family_to_string
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def nonfatal(func, *args):
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try:
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func(*args)
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except Fatal as e:
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log('error: %s\n' % e)
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def ipt_chain_exists(family, table, name):
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if family == socket.AF_INET6:
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cmd = 'ip6tables'
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elif family == socket.AF_INET:
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cmd = 'iptables'
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else:
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raise Exception('Unsupported family "%s"' % family_to_string(family))
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argv = [cmd, '-t', table, '-nL']
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env = {
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'PATH': os.environ['PATH'],
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'LC_ALL': "C",
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}
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p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, env=env)
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for line in p.stdout:
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if line.startswith(b'Chain %s ' % name.encode("ASCII")):
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return True
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rv = p.wait()
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if rv:
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raise Fatal('%r returned %d' % (argv, rv))
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def ipt(family, table, *args):
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if family == socket.AF_INET6:
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argv = ['ip6tables', '-t', table] + list(args)
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elif family == socket.AF_INET:
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argv = ['iptables', '-t', table] + list(args)
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else:
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raise Exception('Unsupported family "%s"' % family_to_string(family))
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debug1('>> %s\n' % ' '.join(argv))
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env = {
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'PATH': os.environ['PATH'],
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'LC_ALL': "C",
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}
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rv = ssubprocess.call(argv, env=env)
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if rv:
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raise Fatal('%r returned %d' % (argv, rv))
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_no_ttl_module = False
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def ipt_ttl(family, *args):
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global _no_ttl_module
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if not _no_ttl_module:
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# we avoid infinite loops by generating server-side connections
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# with ttl 42. This makes the client side not recapture those
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# connections, in case client == server.
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try:
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argsplus = list(args) + ['-m', 'ttl', '!', '--ttl', '42']
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ipt(family, *argsplus)
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except Fatal:
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ipt(family, *args)
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# we only get here if the non-ttl attempt succeeds
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log('sshuttle: warning: your iptables is missing '
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'the ttl module.\n')
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_no_ttl_module = True
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else:
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ipt(family, *args)
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