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Python

"""
A simple command-line interface for Mininet.
The Mininet CLI provides a simple control console which
makes it easy to talk to nodes. For example, the command
mininet> h27 ifconfig
runs 'ifconfig' on host h27.
Having a single console rather than, for example, an xterm for each
node is particularly convenient for networks of any reasonable
size.
The CLI automatically substitutes IP addresses for node names,
so commands like
mininet> h2 ping h3
should work correctly and allow host h2 to ping host h3
Several useful commands are provided, including the ability to
list all nodes ('nodes'), to print out the network topology
('net') and to check connectivity ('pingall', 'pingpair')
and bandwidth ('iperf'.)
"""
from subprocess import call
from cmd import Cmd
from os import isatty
from select import poll, POLLIN
import select
import errno
import sys
import time
import os
import atexit
from mininet.log import info, output, error
from mininet.term import makeTerms, runX11
from mininet.util import ( quietRun, dumpNodeConnections,
dumpPorts )
class CLI( Cmd ):
"Simple command-line interface to talk to nodes."
prompt = 'mininet> '
def __init__( self, mininet, stdin=sys.stdin, script=None,
**kwargs ):
"""Start and run interactive or batch mode CLI
mininet: Mininet network object
stdin: standard input for CLI
script: script to run in batch mode"""
self.mn = mininet
# Local variable bindings for py command
self.locals = { 'net': mininet }
# Attempt to handle input
self.inPoller = poll()
self.inPoller.register( stdin )
self.inputFile = script
Cmd.__init__( self, stdin=stdin, **kwargs )
info( '*** Starting CLI:\n' )
if self.inputFile:
self.do_source( self.inputFile )
return
self.initReadline()
self.run()
readlineInited = False
@classmethod
def initReadline( cls ):
"Set up history if readline is available"
# Only set up readline once to prevent multiplying the history file
if cls.readlineInited:
return
cls.readlineInited = True
try:
# pylint: disable=import-outside-toplevel
from readline import ( read_history_file, write_history_file,
set_history_length )
except ImportError:
pass
else:
history_path = os.path.expanduser( '~/.mininet_history' )
if os.path.isfile( history_path ):
read_history_file( history_path )
set_history_length( 1000 )
def writeHistory():
"Write out history file"
try:
write_history_file( history_path )
except IOError:
# Ignore probably spurious IOError
pass
atexit.register( writeHistory )
def run( self ):
"Run our cmdloop(), catching KeyboardInterrupt"
while True:
try:
# Make sure no nodes are still waiting
for node in self.mn.values():
while node.waiting:
info( 'stopping', node, '\n' )
node.sendInt()
node.waitOutput()
if self.isatty():
quietRun( 'stty echo sane intr ^C' )
self.cmdloop()
break
except KeyboardInterrupt:
# Output a message - unless it's also interrupted
# pylint: disable=broad-except
try:
output( '\nInterrupt\n' )
except Exception:
pass
# pylint: enable=broad-except
def emptyline( self ):
"Don't repeat last command when you hit return."
pass
def getLocals( self ):
"Local variable bindings for py command"
self.locals.update( self.mn )
return self.locals
helpStr = (
'You may also send a command to a node using:\n'
' <node> command {args}\n'
'For example:\n'
' mininet> h1 ifconfig\n'
'\n'
'The interpreter automatically substitutes IP addresses\n'
'for node names when a node is the first arg, so commands\n'
'like\n'
' mininet> h2 ping h3\n'
'should work.\n'
'\n'
'Some character-oriented interactive commands require\n'
'noecho:\n'
' mininet> noecho h2 vi foo.py\n'
'However, starting up an xterm/gterm is generally better:\n'
' mininet> xterm h2\n\n'
)
def do_help( self, line ): # pylint: disable=arguments-renamed
"Describe available CLI commands."
Cmd.do_help( self, line )
if line == '':
output( self.helpStr )
def do_nodes( self, _line ):
"List all nodes."
nodes = ' '.join( sorted( self.mn ) )
output( 'available nodes are: \n%s\n' % nodes )
def do_ports( self, _line ):
"display ports and interfaces for each switch"
dumpPorts( self.mn.switches )
def do_net( self, _line ):
"List network connections."
dumpNodeConnections( self.mn.values() )
def do_sh( self, line ):
"""Run an external shell command
Usage: sh [cmd args]"""
assert self # satisfy pylint and allow override
call( line, shell=True )
# do_py() and do_px() need to catch any exception during eval()/exec()
# pylint: disable=broad-except
def do_py( self, line ):
"""Evaluate a Python expression.
Node names may be used, e.g.: py h1.cmd('ls')"""
try:
# pylint: disable=eval-used
result = eval( line, globals(), self.getLocals() )
if result is None:
return
elif isinstance( result, str ):
output( result + '\n' )
else:
output( repr( result ) + '\n' )
except Exception as e:
output( str( e ) + '\n' )
# We are in fact using the exec() pseudo-function
# pylint: disable=exec-used
def do_px( self, line ):
"""Execute a Python statement.
Node names may be used, e.g.: px print h1.cmd('ls')"""
try:
exec( line, globals(), self.getLocals() )
except Exception as e:
output( str( e ) + '\n' )
# pylint: enable=broad-except,exec-used
def do_pingall( self, line ):
"Ping between all hosts."
self.mn.pingAll( line )
def do_pingpair( self, _line ):
"Ping between first two hosts, useful for testing."
self.mn.pingPair()
def do_pingallfull( self, _line ):
"Ping between all hosts, returns all ping results."
self.mn.pingAllFull()
def do_pingpairfull( self, _line ):
"Ping between first two hosts, returns all ping results."
self.mn.pingPairFull()
def do_iperf( self, line ):
"""Simple iperf TCP test between two (optionally specified) hosts.
Usage: iperf node1 node2"""
args = line.split()
if not args:
self.mn.iperf()
elif len(args) == 2:
hosts = []
err = False
for arg in args:
if arg not in self.mn:
err = True
error( "node '%s' not in network\n" % arg )
else:
hosts.append( self.mn[ arg ] )
if not err:
self.mn.iperf( hosts )
else:
error( 'invalid number of args: iperf src dst\n' )
def do_iperfudp( self, line ):
"""Simple iperf UDP test between two (optionally specified) hosts.
Usage: iperfudp bw node1 node2"""
args = line.split()
if not args:
self.mn.iperf( l4Type='UDP' )
elif len(args) == 3:
udpBw = args[ 0 ]
hosts = []
err = False
for arg in args[ 1:3 ]:
if arg not in self.mn:
err = True
error( "node '%s' not in network\n" % arg )
else:
hosts.append( self.mn[ arg ] )
if not err:
self.mn.iperf( hosts, l4Type='UDP', udpBw=udpBw )
else:
error( 'invalid number of args: iperfudp bw src dst\n' +
'bw examples: 10M\n' )
def do_intfs( self, _line ):
"List interfaces."
for node in self.mn.values():
output( '%s: %s\n' %
( node.name, ','.join( node.intfNames() ) ) )
def do_dump( self, _line ):
"Dump node info."
for node in self.mn.values():
output( '%s\n' % repr( node ) )
def do_link( self, line ):
"""Bring link(s) between two nodes up or down.
Usage: link node1 node2 [up/down]"""
args = line.split()
if len(args) != 3:
error( 'invalid number of args: link end1 end2 [up down]\n' )
elif args[ 2 ] not in [ 'up', 'down' ]:
error( 'invalid type: link end1 end2 [up down]\n' )
else:
self.mn.configLinkStatus( *args )
def do_xterm( self, line, term='xterm' ):
"""Spawn xterm(s) for the given node(s).
Usage: xterm node1 node2 ..."""
args = line.split()
if not args:
error( 'usage: %s node1 node2 ...\n' % term )
else:
for arg in args:
if arg not in self.mn:
error( "node '%s' not in network\n" % arg )
else:
node = self.mn[ arg ]
self.mn.terms += makeTerms( [ node ], term = term )
def do_x( self, line ):
"""Create an X11 tunnel to the given node,
optionally starting a client.
Usage: x node [cmd args]"""
args = line.split()
if not args:
error( 'usage: x node [cmd args]...\n' )
else:
node = self.mn[ args[ 0 ] ]
cmd = args[ 1: ]
self.mn.terms += runX11( node, cmd )
def do_gterm( self, line ):
"""Spawn gnome-terminal(s) for the given node(s).
Usage: gterm node1 node2 ..."""
self.do_xterm( line, term='gterm' )
def do_exit( self, _line ):
"Exit"
assert self # satisfy pylint and allow override
return 'exited by user command'
def do_quit( self, line ):
"Exit"
return self.do_exit( line )
def do_EOF( self, line ):
"Exit"
output( '\n' )
return self.do_exit( line )
def isatty( self ):
"Is our standard input a tty?"
return isatty( self.stdin.fileno() )
def do_noecho( self, line ):
"""Run an interactive command with echoing turned off.
Usage: noecho [cmd args]"""
if self.isatty():
quietRun( 'stty -echo' )
self.default( line )
if self.isatty():
quietRun( 'stty echo' )
def do_source( self, line ):
"""Read commands from an input file.
Usage: source <file>"""
args = line.split()
if len(args) != 1:
error( 'usage: source <file>\n' )
return
try:
with open( args[ 0 ] ) as self.inputFile:
while True:
line = self.inputFile.readline()
if len( line ) > 0:
self.onecmd( line )
else:
break
except IOError:
error( 'error reading file %s\n' % args[ 0 ] )
self.inputFile.close()
self.inputFile = None
def do_dpctl( self, line ):
"""Run dpctl (or ovs-ofctl) command on all switches.
Usage: dpctl command [arg1] [arg2] ..."""
args = line.split()
if len(args) < 1:
error( 'usage: dpctl command [arg1] [arg2] ...\n' )
return
for sw in self.mn.switches:
output( '*** ' + sw.name + ' ' + ('-' * 72) + '\n' )
output( sw.dpctl( *args ) )
def do_time( self, line ):
"Measure time taken for any command in Mininet."
start = time.time()
self.onecmd(line)
elapsed = time.time() - start
self.stdout.write("*** Elapsed time: %0.6f secs\n" % elapsed)
def do_links( self, _line ):
"Report on links"
for link in self.mn.links:
output( link, link.status(), '\n' )
def do_switch( self, line ):
"Starts or stops a switch"
args = line.split()
if len(args) != 2:
error( 'invalid number of args: switch <switch name>'
'{start, stop}\n' )
return
sw = args[ 0 ]
command = args[ 1 ]
if sw not in self.mn or self.mn.get( sw ) not in self.mn.switches:
error( 'invalid switch: %s\n' % args[ 1 ] )
else:
sw = args[ 0 ]
command = args[ 1 ]
if command == 'start':
self.mn.get( sw ).start( self.mn.controllers )
elif command == 'stop':
self.mn.get( sw ).stop( deleteIntfs=False )
else:
error( 'invalid command: '
'switch <switch name> {start, stop}\n' )
def do_wait( self, _line ):
"Wait until all switches have connected to a controller"
self.mn.waitConnected()
def default( self, line ):
"""Called on an input line when the command prefix is not recognized.
Overridden to run shell commands when a node is the first
CLI argument. Past the first CLI argument, node names are
automatically replaced with corresponding IP addrs."""
first, args, line = self.parseline( line )
if first in self.mn:
if not args:
error( '*** Please enter a command for node: %s <cmd>\n'
% first )
return
node = self.mn[ first ]
rest = args.split( ' ' )
# Substitute IP addresses for node names in command
# If updateIP() returns None, then use node name
rest = [ self.mn[ arg ].defaultIntf().updateIP() or arg
if arg in self.mn else arg
for arg in rest ]
rest = ' '.join( rest )
# Run cmd on node:
node.sendCmd( rest )
self.waitForNode( node )
else:
error( '*** Unknown command: %s\n' % line )
def waitForNode( self, node ):
"Wait for a node to finish, and print its output."
# Pollers
nodePoller = poll()
nodePoller.register( node.stdout )
bothPoller = poll()
bothPoller.register( self.stdin, POLLIN )
bothPoller.register( node.stdout, POLLIN )
if self.isatty():
# Buffer by character, so that interactive
# commands sort of work
quietRun( 'stty -icanon min 1' )
while True:
try:
bothPoller.poll()
# XXX BL: this doesn't quite do what we want.
# pylint: disable=condition-evals-to-constant
if False and self.inputFile:
key = self.inputFile.read( 1 )
if key != '':
node.write( key )
else:
self.inputFile = None
# pylint: enable=condition-evals-to-constant
if isReadable( self.inPoller ):
key = self.stdin.read( 1 )
node.write( key )
if isReadable( nodePoller ):
data = node.monitor()
output( data )
if not node.waiting:
break
except KeyboardInterrupt:
# There is an at least one race condition here, since
# it's possible to interrupt ourselves after we've
# read data but before it has been printed.
node.sendInt()
except select.error as e:
# pylint: disable=unpacking-non-sequence
# pylint: disable=unbalanced-tuple-unpacking
errno_, errmsg = e.args
if errno_ != errno.EINTR:
error( "select.error: %s, %s" % (errno_, errmsg) )
node.sendInt()
def precmd( self, line ):
"allow for comments in the cli"
if '#' in line:
line = line.split( '#' )[ 0 ]
return line
# Helper functions
def isReadable( poller ):
"Check whether a Poll object has a readable fd."
for fdmask in poller.poll( 0 ):
mask = fdmask[ 1 ]
if mask & POLLIN:
return True
return False