NePA TesT: Community Network Emulator

#!/usr/bin/env python

'''Node objects for Mininet.'''

from subprocess import Popen, PIPE, STDOUT

import os, signal, sys, select

flush = sys.stdout.flush

from mininet.logging_mod import lg

from mininet.util import quietRun, macColonHex, ipStr

class Node(object):

    '''A virtual network node is simply a shell in a network namespace.

       We communicate with it using pipes.'''

    inToNode = {}

    outToNode = {}

    def __init__(self, name, inNamespace = True):

        self.name = name

        closeFds = False # speed vs. memory use

        # xpg_echo is needed so we can echo our sentinel in sendCmd

        cmd = ['/bin/bash', '-O', 'xpg_echo']

        self.inNamespace = inNamespace

        if self.inNamespace:

            cmd = ['netns'] + cmd

        self.shell = Popen(cmd, stdin = PIPE, stdout = PIPE, stderr = STDOUT,

            close_fds = closeFds)

        self.stdin = self.shell.stdin

        self.stdout = self.shell.stdout

        self.pollOut = select.poll()

        self.pollOut.register(self.stdout)

        # Maintain mapping between file descriptors and nodes

        # This could be useful for monitoring multiple nodes

        # using select.poll()

        self.outToNode[self.stdout.fileno()] = self

        self.inToNode[self.stdin.fileno()] = self

        self.pid = self.shell.pid

        self.intfCount = 0

        self.intfs = [] # list of interface names, as strings

        self.ips = {}

        self.connection = {}

        self.waiting = False

        self.execed = False

    def fdToNode(self, f):

        '''Insert docstring.

        @param f unknown

        @return bool unknown

        '''

        node = self.outToNode.get(f)

        return node or self.inToNode.get(f)

    def cleanup(self):

        '''Help python collect its garbage.'''

        self.shell = None

    # Subshell I/O, commands and control

    def read(self, fileno_max):

        '''Insert docstring.

        @param fileno_max unknown

        '''

        return os.read(self.stdout.fileno(), fileno_max)

    def write(self, data):

        '''Write data to node.

        @param data string

        '''

        os.write(self.stdin.fileno(), data)

    def terminate(self):

        '''Send kill signal to Node and cleanup after it.'''

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

        self.cleanup()

    def stop(self):

        '''Stop node.'''

        self.terminate()

    def waitReadable(self):

        '''Poll on node.'''

        self.pollOut.poll()

    def sendCmd(self, cmd):

        '''Send a command, followed by a command to echo a sentinel,

           and return without waiting for the command to complete.'''

        assert not self.waiting

        if cmd[-1] == '&':

            separator = '&'

            cmd = cmd[:-1]

        else:

            separator = ';'

        if isinstance(cmd, list):

            cmd = ' '.join(cmd)

        self.write(cmd + separator + ' echo -n "\\0177" \n')

        self.waiting = True

    def monitor(self):

        '''Monitor the output of a command, returning (done, data).'''

        assert self.waiting

        self.waitReadable()

        data = self.read(1024)

        if len(data) > 0 and data[-1] == chr(0177):

            self.waiting = False

            return True, data[:-1]

        else:

            return False, data

    def sendInt(self):

        '''Send ^C, hopefully interrupting a running subprocess.'''

        self.write(chr(3))

    def waitOutput(self):

        '''Wait for a command to complete.

        Completion is signaled by a sentinel character, ASCII(127) appearing in

        the output stream.  Wait for the sentinel and return the output,

        including trailing newline.

        '''

        assert self.waiting

        output = ''

        while True:

            self.waitReadable()

            data = self.read(1024)

            if len(data) > 0  and data[-1] == chr(0177):

                output += data[:-1]

                break

            else: output += data

        self.waiting = False

        return output

    def cmd(self, cmd):

        '''Send a command, wait for output, and return it.

        @param cmd string

        '''

        self.sendCmd(cmd)

        return self.waitOutput()

    def cmdPrint(self, cmd):

        '''Call cmd and printing its output

        @param cmd string

        '''

        #lg.info('*** %s : %s', self.name, cmd)

        result = self.cmd(cmd)

        #lg.info('%s\n', result)

        return result

    # Interface management, configuration, and routing

    def intfName(self, n):

        '''Construct a canonical interface name node-intf for interface N.'''

        return self.name + '-eth' + repr(n)

    def newIntf(self):

        '''Reserve and return a new interface name.'''

        intfName = self.intfName(self.intfCount)

        self.intfCount += 1

        self.intfs += [intfName]

        return intfName

    def setMAC(self, intf, mac):

        '''Set the MAC address for an interface.

        @param mac MAC address as unsigned int

        '''

        mac_str = macColonHex(mac)

        result = self.cmd(['ifconfig', intf, 'down'])

        result += self.cmd(['ifconfig', intf, 'hw', 'ether', mac_str])

        result += self.cmd(['ifconfig', intf, 'up'])

        return result

    def setARP(self, ip, mac):

        '''Add an ARP entry.

        @param ip IP address as unsigned int

        @param mac MAC address as unsigned int

        '''

        ip_str = ipStr(ip)

        mac_str = macColonHex(mac)

        result = self.cmd(['arp', '-s', ip_str, mac_str])

        return result

    def setIP(self, intf, ip, bits):

        '''Set the IP address for an interface.

        @param intf string, interface name

        @param ip IP address as integer

        @param bits

        '''

        result = self.cmd(['ifconfig', intf, ip + bits, 'up'])

        self.ips[intf] = ip

        return result

    def setHostRoute(self, ip, intf):

        '''Add route to host.

        @param ip IP address as dotted decimal

        @param intf string, interface name

        '''

        return self.cmd('route add -host ' + ip + ' dev ' + intf)

    def setDefaultRoute(self, intf):

        '''Set the default route to go through intf.

        @param intf string, interface name

        '''

        self.cmd('ip route flush')

        return self.cmd('route add default ' + intf)

    def IP(self):

        '''Return IP address of first interface'''

        if len(self.intfs) > 0:

            return self.ips.get(self.intfs[ 0 ], None)

    def intfIsUp(self):

        '''Check if one of our interfaces is up.'''

        return 'UP' in self.cmd('ifconfig ' + self.intfs[0])

    # Other methods

    def __str__(self):

        result = self.name + ':'

        if self.IP():

            result += ' IP=' + self.IP()

        result += ' intfs=' + ','.join(self.intfs)

        result += ' waiting=' + repr(self.waiting)

        return result

class Host(Node):

    '''A host is simply a Node.'''

    pass

class Switch(Node):

    '''A Switch is a Node that is running (or has execed)

       an OpenFlow switch.'''

    def sendCmd(self, cmd):

        '''Send command to Node.

        @param cmd string

        '''

        if not self.execed:

            return Node.sendCmd(self, cmd)

        else:

            lg.error('*** Error: %s has execed and cannot accept commands' %

                     self.name)

    def monitor(self):

        '''Monitor node.'''

        if not self.execed:

            return Node.monitor(self)

        else:

            return True, ''

class UserSwitch(Switch):

    def __init__(self, name):

        '''Init.

        @param name

        '''

        Node.__init__(self, name, inNamespace = True)

    def start(self, controllers):

        '''Start OpenFlow reference user datapath.

        Log to /tmp/sN-{ofd,ofp}.log.

        @param controllers dict of controller names to objects

        '''

        if 'c0' not in controller:

            raise Exception('User datapath start() requires controller c0')

        controller = controllers['c0']

        ofdlog = '/tmp/' + self.name + '-ofd.log'

        ofplog = '/tmp/' + self.name + '-ofp.log'

        self.cmd('ifconfig lo up')

        intfs = self.intfs[1:] # 0 is mgmt interface

        self.cmdPrint('ofdatapath -i ' + ','.join(intfs) +

                      ' ptcp: 1> ' + ofdlog + ' 2> ' + ofdlog + ' &')

        self.cmdPrint('ofprotocol tcp:' + controller.IP() +

                      ' tcp:localhost --fail=closed 1> ' + ofplog + ' 2>' +

                      ofplog + ' &')

    def stop(self):

        '''Stop OpenFlow reference user datapath.'''

        self.cmd('kill %ofdatapath')

        self.cmd('kill %ofprotocol')

class KernelSwitch(Switch):

    def __init__(self, name, datapath = None):

        '''Init.

        @param name

        @param datapath string, datapath name

        '''

        self.dp = datapath

        Node.__init__(self, name, inNamespace = (datapath == None))

    def start(self, ignore):

        '''Start up reference kernel datapath.'''

        ofplog = '/tmp/' + self.name + '-ofp.log'

        quietRun('ifconfig lo up')

        # Delete local datapath if it exists;

        # then create a new one monitoring the given interfaces

        quietRun('dpctl deldp ' + self.dp)

        self.cmdPrint('dpctl adddp ' + self.dp)

        self.cmdPrint('dpctl addif ' + self.dp + ' ' + ' '.join(self.intfs))

        # Run protocol daemon

        self.cmdPrint('ofprotocol' +

                      ' ' + self.dp + ' tcp:127.0.0.1 ' +

                      ' --fail=closed 1> ' + ofplog + ' 2>' + ofplog + ' &')

        self.execed = False # XXX until I fix it

    def stop(self):

        '''Terminate reference kernel datapath.'''

        quietRun('dpctl deldp ' + self.dp)

        # In theory the interfaces should go away after we shut down.

        # However, this takes time, so we're better off to remove them

        # explicitly so that we won't get errors if we run before they

        # have been removed by the kernel. Unfortunately this is very slow.

        self.cmd('kill %ofprotocol')

        for intf in self.intfs:

            quietRun('ip link del ' + intf)

            lg.info('.')

class Controller(Node):

    '''A Controller is a Node that is running (or has execed) an

      OpenFlow controller.'''

    def __init__(self, name, inNamespace = False, controller = 'controller',

                 cargs = '-v ptcp:', cdir = None):

        self.controller = controller

        self.cargs = cargs

        self.cdir = cdir

        Node.__init__(self, name, inNamespace = inNamespace)

    def start(self):

        '''Start <controller> <args> on controller.

        Log to /tmp/cN.log

        '''

        cout = '/tmp/' + self.name + '.log'

        if self.cdir is not None:

            self.cmdPrint('cd ' + self.cdir)

        self.cmdPrint(self.controller + ' ' + self.cargs +

            ' 1> ' + cout + ' 2> ' + cout + ' &')

        self.execed = False # XXX Until I fix it

    def stop(self):

        '''Stop controller.'''

        self.cmd('kill %' + self.controller)

        self.terminate()

class ControllerParams(object):

    '''Container for controller IP parameters.'''

    def __init__(self, ip, subnet_size):

        '''Init.

        @param ip integer, controller IP

        @param subnet_size integer, ex 8 for slash-8, covering 17M

        '''

        self.ip = ip

        self.subnet_size = subnet_size

class NOX(Controller):

    '''Controller to run a NOX application.'''

    def __init__(self, name, inNamespace = False, nox_args = None, **kwargs):

        '''Init.

        @param name name to give controller

        @param nox_args list of args, or single arg, to pass to NOX

        '''

        if type(nox_args) != list:

            nox_args = [nox_args]

        if not nox_args:

            nox_args = ['packetdump']

        nox_core_dir = os.environ['NOX_CORE_DIR']

        if not nox_core_dir:

            raise Exception('please set NOX_CORE_DIR env var\n')

        Controller.__init__(self, name,

            controller = nox_core_dir + '/nox_core',

            cargs = '--libdir=/usr/local/lib -v -i ptcp: ' + \

                    ' '.join(nox_args),

            cdir = nox_core_dir, **kwargs)