Function main

sshuttle/firewall.py:200–427

(method_name, syslog)

# supersede it in the transproxy list, at least, so the leftover rules
# are hopefully harmless.
def main(method_name, syslog):
    helpers.logprefix = 'fw: '
    stdin, stdout = setup_daemon()
    hostmap = {}
    debug1('Starting firewall with Python version %s'
           % platform.python_version())

    if method_name == "auto":
        method = get_auto_method()
    else:
        method = get_method(method_name)

    if syslog:
        ssyslog.start_syslog()
        ssyslog.stderr_to_syslog()

    if not method.is_supported():
        raise Fatal("The %s method is not supported on this machine. "
                    "Check that the appropriate programs are in your "
                    "PATH." % method_name)

    debug1('ready method name %s.' % method.name)
    stdout.write(('READY %s\n' % method.name).encode('ASCII'))
    stdout.flush()

    def _read_next_string_line():
        try:
            line = stdin.readline(128)
            if not line:
                return  # parent probably exited
            return line.decode('ASCII').strip()
        except IOError as e:
            # On windows, ConnectionResetError is thrown when parent process closes it's socket pair end
            debug3('read from stdin failed: %s' % (e,))
            return
    # we wait until we get some input before creating the rules.  That way,
    # sshuttle can launch us as early as possible (and get sudo password
    # authentication as early in the startup process as possible).
    try:
        line = _read_next_string_line()
        if not line:
            return  # parent probably exited
    except IOError as e:
        # On windows, ConnectionResetError is thrown when parent process closes it's socket pair end
        debug3('read from stdin failed: %s' % (e,))
        return

    subnets = []
    if line != 'ROUTES':
        raise Fatal('expected ROUTES but got %r' % line)
    while 1:
        line = _read_next_string_line()
        if not line:
            raise Fatal('expected route but got %r' % line)
        elif line.startswith("NSLIST"):
            break
        try:
            (family, width, exclude, ip, fport, lport) = line.split(',', 5)