/mandos/trunk

#!/usr/bin/python

import SocketServer

import socket

import select

from optparse import OptionParser

import datetime

import errno

import gnutls.crypto

import gnutls.connection

import gnutls.errors

import ConfigParser

import sys

import re

import os

import signal

class Client(object):

    def __init__(self, name=None, options=None, dn=None,

                 password=None, passfile=None, fqdn=None,

                 timeout=None, interval=-1):

        self.name = name

        self.dn = dn

        if password:

            self.password = password

        elif passfile:

            self.password = open(passfile).readall()

        else:

            print "No Password or Passfile in client config file"

            # raise RuntimeError XXX

            self.password = "gazonk"

        self.fqdn = fqdn                # string

        self.created = datetime.datetime.now()

        self.last_seen = None           # datetime.datetime()

        if timeout is None:

            timeout = options.timeout

        self.timeout = timeout          # datetime.timedelta()

        if interval == -1:

            interval = options.interval

        self.interval = interval        # datetime.timedelta()

        self.next_check = datetime.datetime.now() # datetime.datetime()

        self.checker = None             # or a subprocess.Popen()

    def check_action(self, now=None):

        """The checker said something and might have completed.

        Check if is has, and take appropriate actions."""

        if self.checker.poll() is None:

            # False alarm, no result yet

            #self.checker.read()

            return

        if now is None:

            now = datetime.datetime.now()

        if self.checker.returncode == 0:

            self.last_seen = now

        while self.next_check <= now:

            self.next_check += self.interval

    handle_request = check_action

    def start_checker(self):

        self.stop_checker()

        try:

            self.checker = subprocess.Popen("sleep 1; fping -q -- %s"

                                            % re.escape(self.fqdn),

                                            stdout=subprocess.PIPE,

                                            close_fds=True,

                                            shell=True, cwd="/")

        except subprocess.OSError, e:

            print "Failed to start subprocess:", e

    def stop_checker(self):

        if self.checker is None:

            return

        os.kill(self.checker.pid, signal.SIGTERM)

        if self.checker.poll() is None:

            os.kill(self.checker.pid, signal.SIGKILL)

        self.checker = None

    __del__ = stop_checker

    def fileno(self):

        if self.checker is None:

            return None

        return self.checker.stdout.fileno()

    def next_stop(self):

        """The time when something must be done about this client"""

        return min(self.last_seen + self.timeout, self.next_check)

    def still_valid(self, now=None):

        """Has this client's timeout not passed?"""

        if now is None:

            now = datetime.datetime.now()

        return now < (self.last_seen + timeout)

    def it_is_time_to_check(self, now=None):

        if now is None:

            now = datetime.datetime.now()

        return self.next_check <= now

class server_metaclass(type):

    "Common behavior for the UDP and TCP server classes"

    def __new__(cls, name, bases, attrs):

        attrs["address_family"] = socket.AF_INET6

        attrs["allow_reuse_address"] = True

        def server_bind(self):

            if self.options.interface:

                if not hasattr(socket, "SO_BINDTODEVICE"):

                    # From /usr/include/asm-i486/socket.h

                    socket.SO_BINDTODEVICE = 25

                try:

                    self.socket.setsockopt(socket.SOL_SOCKET,

                                           socket.SO_BINDTODEVICE,

                                           self.options.interface)

                except socket.error, error:

                    if error[0] == errno.EPERM:

                        print "Warning: No permission to bind to interface", \

                              self.options.interface

                    else:

                        raise error

            return super(type(self), self).server_bind()

        attrs["server_bind"] = server_bind

        def init(self, *args, **kwargs):

            if "options" in kwargs:

                self.options = kwargs["options"]

                del kwargs["options"]

            if "clients" in kwargs:

                self.clients = kwargs["clients"]

                del kwargs["clients"]

            if "credentials" in kwargs:

                self.credentials = kwargs["credentials"]

                del kwargs["credentials"]

            return super(type(self), self).__init__(*args, **kwargs)

        attrs["__init__"] = init

        return type.__new__(cls, name, bases, attrs)

class udp_handler(SocketServer.DatagramRequestHandler, object):

    def handle(self):

        self.wfile.write("Polo")

        print "UDP request answered"

class IPv6_UDPServer(SocketServer.UDPServer, object):

    __metaclass__ = server_metaclass

    def verify_request(self, request, client_address):

        print "UDP request came"

        return request[0] == "Marco"

class tcp_handler(SocketServer.BaseRequestHandler, object):

    def handle(self):

        print "TCP request came"

        print "Request:", self.request

        print "Client Address:", self.client_address

        print "Server:", self.server

        session = gnutls.connection.ServerSession(self.request,

                                                  self.server.credentials)

        session.handshake()

        if session.peer_certificate:

            print "DN:", session.peer_certificate.subject

        try:

            session.verify_peer()

        except gnutls.errors.CertificateError, error:

            print "Verify failed", error

            session.bye()

            return

        try:

            session.send(dict((client.dn, client.password)

                              for client in self.server.clients)

                         [session.peer_certificate.subject])

        except KeyError:

            session.send("gazonk")

            # Log maybe? XXX

        session.bye()

class IPv6_TCPServer(SocketServer.ForkingTCPServer, object):

    __metaclass__ = server_metaclass

    request_queue_size = 1024

in6addr_any = "::"

def string_to_delta(interval):

    """Parse a string and return a datetime.timedelta

    >>> string_to_delta('7d')

    datetime.timedelta(7)

    >>> string_to_delta('60s')

    datetime.timedelta(0, 60)

    >>> string_to_delta('60m')

    datetime.timedelta(0, 3600)

    >>> string_to_delta('24h')

    datetime.timedelta(1)

    >>> string_to_delta(u'1w')

    datetime.timedelta(7)

    """

    try:

        suffix=unicode(interval[-1])

        value=int(interval[:-1])

        if suffix == u"d":

            delta = datetime.timedelta(value)

        elif suffix == u"s":

            delta = datetime.timedelta(0, value)

        elif suffix == u"m":

            delta = datetime.timedelta(0, 0, 0, 0, value)

        elif suffix == u"h":

            delta = datetime.timedelta(0, 0, 0, 0, 0, value)

        elif suffix == u"w":

            delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)

        else:

            raise ValueError

    except (ValueError, IndexError):

        raise ValueError

    return delta

def main():

    parser = OptionParser()

    parser.add_option("-i", "--interface", type="string",

                      default="eth0", metavar="IF",

                      help="Interface to bind to")

    parser.add_option("--cert", type="string", default="cert.pem",

                      metavar="FILE",

                      help="Public key certificate to use")

    parser.add_option("--key", type="string", default="key.pem",

                      metavar="FILE",

                      help="Private key to use")

    parser.add_option("--ca", type="string", default="ca.pem",

                      metavar="FILE",

                      help="Certificate Authority certificate to use")

    parser.add_option("--crl", type="string", default="crl.pem",

                      metavar="FILE",

                      help="Certificate Revokation List to use")

    parser.add_option("-p", "--port", type="int", default=49001,

                      help="Port number to receive requests on")

    parser.add_option("--dh", type="int", metavar="BITS",

                      help="DH group to use")

    parser.add_option("-t", "--timeout", type="string", # Parsed later

                      default="15m",

                      help="Amount of downtime allowed for clients")

    parser.add_option("--interval", type="string", # Parsed later

                      default="5m",

                      help="How often to check that a client is up")

    parser.add_option("--check", action="store_true", default=False,

                      help="Run self-test")

    (options, args) = parser.parse_args()

    if options.check:

        import doctest

        doctest.testmod()

        sys.exit()

    # Parse the time arguments

    try:

        options.timeout = string_to_delta(options.timeout)

    except ValueError:

        parser.error("option --timeout: Unparseable time")

    try:

        options.interval = string_to_delta(options.interval)

    except ValueError:

        parser.error("option --interval: Unparseable time")

    cert = gnutls.crypto.X509Certificate(open(options.cert).read())

    key = gnutls.crypto.X509PrivateKey(open(options.key).read())

    ca = gnutls.crypto.X509Certificate(open(options.ca).read())

    crl = gnutls.crypto.X509CRL(open(options.crl).read())

    cred = gnutls.connection.X509Credentials(cert, key, [ca], [crl])

    # Parse config file

    defaults = {}

    client_config_object = ConfigParser.SafeConfigParser(defaults)

    client_config_object.read("mandos-clients.conf")

    clients = [Client(name=section, options=options,

                      **(dict(client_config_object.items(section))))

               for section in client_config_object.sections()]

    udp_server = IPv6_UDPServer((in6addr_any, options.port),

                                udp_handler,

                                options=options)

    tcp_server = IPv6_TCPServer((in6addr_any, options.port),

                                tcp_handler,

                                options=options,

                                clients=clients,

                                credentials=cred)

    while True:

        try:

            input, out, err = select.select((udp_server,

                                             tcp_server), (), ())

            if not input:

                pass

            else:

                for obj in input:

                    obj.handle_request()

        except KeyboardInterrupt:

            break

    # Cleanup here

    for client in clients:

        client.stop_checker()

if __name__ == "__main__":

    main()