Python Script: ToSCalc.py

ToSCalc.py

En esta entrada se muestra el código fuente del script ToSCalc.py con el que calcular los distintos valores ToS y DSCP para configuraciones de calidades de servicio.

Sintaxis: ./TosCalc.py VALUE

VALUE corresponde a los posibles valores configurables dentro del campo IP Precedence o Class Selectors para la priorización de tráfico en las redes IP.

Código fuente:

#!/usr/bin/env python
#
# Name: ToSCalc.py
# Description: Calculate ToS and DSCP values for IP Precedence
# or Class Selector argument.
# Author: Brixton Cat
# Date: 10 Mar 2012
# Version: 0.1
# Sintax: ./ToSCalc.py VALUE
#

### Dependencies
import sys

### Functions
def Arguments(decimal):
    """ This function check the introduced argument and call ThreeBits
    function if the value is correct """

    # If not valid value, exit of script
    if decimal < 1 or decimal > 7:
        print "ERROR: %d not valid CS or IP Precedence value" % \
            decimal
        sys.exit(1)
    else:
        ThreeBits(decimal)

def ThreeBits(decimal):
    """ This function convert decimal argument to a 3 bits value and
    check correct lenght of this """

    # Array ['0', 'value']
    bina = bin(decimal).split('b')

    # If less of 3 bits, add 0s to left of binary variable
    if bina[1] < "3":
        rest = 3 - len(bina[1])
        binary = str(0) * rest + bina[1]
    else:
        binary = bina[1]
 
    # Run SixBits functions
    SixBits(decimal, binary)

def EightBits(decimal, binary, dscpb, dscpd):
    """ This function add 0s to right of tosb variable and run Results
    function with all prints values """

    # Rest of 8 and binary lenght
    rest = 8 - len(binary)
    # Type of Service binary value
    tosb = binary + str(0) * rest
    # Type of Service decimal value
    tosd = int(tosb, 2)

    # Call Results function with all values
    Results(decimal, binary, dscpb, dscpd, tosb, tosd)

def Main():
    """ Declare decimal variable and run Arguments function with
    this value """

    # Fisrt argument of the script
    decimal = int(sys.argv[1])
    # Run Arguments functions
    Arguments(decimal)

def Results(decimal, binary, dscpb, dscpd, tosb, tosd):
    """ Prints values relationated with IP Precedence or Class
    Selectors introduced argument"""

    # Header
    print "Value  3bits   DSCP Bin  DSCP   ToS Bin   ToS"
    print "-----  -----   --------  ----   -------   ---"
    # Values
    print "  %d\t%s\t%s\t  %d\t%s  %d" % \
        (decimal, binary, dscpb, dscpd, tosb, tosd)
 
def SixBits(decimal, binary):
    """ This function add 0s to right of dscpb variable and calculate
    their decimal value """

    # DSCP binary value
    dscpb = binary + str(0) * 3
    # DSCP decimal value
    dscpd = int(dscpb, 2)
 
    # Run EightBits function
    EightBits(decimal, binary, dscpb, dscpd)

### Script
Main()

### Exit
# Exit Codes
# 0 -> Normal exit
# 1 -> No valid argument
sys.exit(0)

#EOF
##FVE

En la siguiente entrada hay información sobre el mismo así como algunas pruebas multiplataforma.

Un saludo, Brixton Cat.