Wayne Marquette > SNMP-Util > SNMP::Util

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Module Version: 1.8   Source  

NAME ^

SNMP::Util - Snmp modules to perform snmp set,get,walk,next,walk_hash etc.

SYNOPSIS ^

use SNMP::Util;

## Documentation (POD) =head1 NAME

 Perl SNMP utilities - SNMP::Util - Version 1.8

DESCRIPTION ^

This Perl library is a set of utilities for configuring and monitoring SNMP based devices. This library requires the UCD port of SNMP and the SNMP.pm module writted by Joe Marzot.

Version ^

    1.0 Initial Release
    1.1 Fixed Manifest File
    1.2 Added get_hash / walk_hash now calls walk / Modified output in poll_value
    1.3 Added use strict to library and fixed some bugs with my vars
    1.4 Fixed code to elminate perl warning
    1.5 Changed all mapInt functions to mapEnum - (support for mapInt not in 
        Joe Marzot's version 1.8).
    1.6 Updated docs html and text
    1.7 Includes patches from Charles Anderson 
    1.8 Includes patches from  tyoshida

Software requirements ^

The following applications need to be built and installed before running the SNMP::Util application.

    ucd-snmp-3.5 - ftp:://ftp.ece.ucdavis.edu:/pub/snmp/ucd-snmp.tar.gz
    SNMP-1.8 - www.perl.com/CPAN

Summary of functions ^

 get - snmpget and return formatted array
 get_hash - snmpget and return hash
 get_set_restore - get value, set new range of values and restore value
 next - snmpnext and return formatted array
 ping_check - get uptime and return 1 if reachable
 ping_check_exit - get uptime and exit if not reachable
 poll_device - poll a device until it becomes reachable
 poll_devices - poll several devices until they becomes reachable
 poll_value - snmpget in a loop until variable reaches desired state
 set - snmpset and return
 set_get - snmpset followed by get and check 
 walk - snmpwalk and return formatted array
 walk_hash - snmpwalk and return hash ($hash->{mibname}{index} = value)

Creation on the SNMP::Util object ^

You must first do a use statement to pull in the library. Then the snmp object can be created.

 #!/usr/local/lib/perl
 use lib "put lib path here" 
 use SNMP::Util;

 The SNMP::Util object is created as follows:

 $snmp = new SNMP::Util(-device => $IP,
                       -community => $community, 
                       -timeout => 5,             
                       -retry => 0,             
                       -poll => 'on',            
                       -poll_timeout => 5,        
                       -verbose => 'off',         
                       -errmode => 'return',    
                       -delimiter => ' ', 
                      )
 
 community = snmp community string
 timeout = snmp timeout in seconds (You may also use sub second values ie 0.5)
 retry = number of snmp retries on timeouts
 poll = poll the unreachable device after number of retries reached and then retry again
 poll timeout = poll timeout in minutes default = 5 minutes
 verbose = controls the output of the snmp low level library
 errmode = error mode ('return' on error or 'die' on error) default = return
 delimeter = specifies the character to use between octets when getting octet-strings
 
 
 Note: Delimiter can also be set by using the setting the Global variable as follows:
       $SNMP::Util::Delimiter = '-'

Creating and using multiple objects

First populate an array of IP addresses:

 @IP_array = ('1.1.1.1','1.1.1.2','1.1.1.3','1.1.1.4')
    
 foreach $IP (@IP_array){

    $snmp->{$IP} = new SNMP::Util(-device => $IP,
                      -community => $community, 
                      -timeout => 5,             
                      -retry => 0,               
                      -poll => 'on',          
                      -delimiter => ' ', 
                      )
 }

 #Now get the uptime for each switch
 foreach $IP (@IP_array){
     $uptime = $snmp->{$IP}->get('v','sysUpTime.0')
     print "Uptime for $IP = $uptime\n"
 }

How to use the object for a simple snmpget ^

   $uptime = $snmp->get('v','sysUpTime.0')
             where 'v', is the format of the output (v = value)
             and $uptime contains the system uptime in 10ths of seconds

MIB Loading ^

The SNMP::Util module loads the mib using the SNMP::Util_env.pm module by using the following statements.

 use SNMP::Util_env
 # Initialize mib
 &SNMP::initMib()
 
 You must update the SNMP::Util_env.pm file or simply set up these environment
 variables and the SNMP::Util_env.pm file will not override them.
 
 The environment variables are as follows:

 $ENV{'MIBDIRS'} = '/usr/local/lib/snmp/mibs' 
 $ENV{'MIBFILES'} = '/ats/data/mibs/rfc1850.mib:
 /ats/data/mibs/rfc1406.mib:/ats/data/mibs/rfc1407.mib:
 /ats/data/mibs/rfc1595.mib:/ats/data/mibs/rfc1724.mib'
   
 You can specify whatever MIBS you would like to load.

Error Handling method ^

All error handling is done through the error handling method (error). The error message can be obtained by using the method (errmsg) The detailed error message can be obtained by using the method (errmsg_detail)

 This error method returns a boolean result to indicate if an error ocurred

 example:

    if ($snmp->error){
        $error = $snmp->errmsg;
        $error_detail = $snmp->errmsg_detail;
        print "snmp error = $error\n";
        print "snmp error detail = $error_detail\n";
    }

Print Output Logging ^

The printing of output is controlled by the logging routine. the amount of output is configured by setting the MAX_LOG_LEVEL environment variable. There are four levels of output logging: (none,status,fail,debug). You may also set the logging using the global variable Max_log_level.

 none = print  no output (use errmsg only for errors)
 status = print general status information
 fail = print general status and failures
 debug = print general status, failures, and debug information
  
 You can set the environment variable in your environment or inside the 
 program using the following format:
 
    $env{'MAX_LOG_LEVEL'} = 'debug'

    or using the global 
    $SNMP::Util::Max_log_level = 'debug'

 Example Output from Logging:

    get (noSuchName) There is no such variable name in this MIB.
    snmpget 100.100.100.1 public 1.3.6.1.2.1.2.2.1.1.1 1.3.6.1.2.1.2.2.1.7.1
    snmpget 100.100.100.1 public ifIndex.1 ifAdminStatus.1
    snmp error index = 1
   
    Note: error index = the index of the var bind that failed

Formatting SNMP output (get, next, walk) ^

The SNMP utilities have a formatting function which will format the return values which are most cases an array.

 The format options are specified as strings as follows:
 
 print " format string = oOnNtvei\n"
 print " o = oid with index\n"
 print " O = oid without index\n"
 print " n = name with index\n"
 print " N = name without index\n"
 print " t = type\n"
 print " v = value\n" 
 print " e = enumeration\n"
 print " i = instance of the mib variable\n\n"
 
 Note: enumerations apply to integers and timeticks.  It will convert integer values
 to enumerations and it will convert timeticks to days,hours,minutes,seconds.
 
 example usage:
 
 @result = $snmp->get('nve','sysUptime.0')
 $result[0] = sysUptime.0
 $result[1] = 13392330
 $result[2] = 1 days, 13:12:03
 
 Note: Any format can be used for the (get,walk,next routines)
       Only 'e' or 'v' is needed in the walk_hash routine.

This formatting was designed to allow the user to format the output in whatever format they need for there application. You may want to use the 'v' option when comparing timetick values, but you may want to use the 'e' option for the human readable display.

The snmpget routine may be equated to an array if the formatting has more than one value or it may be equated to a scalar value if the formatting has only one value. It must be equated to an array if the snmpget is a multi var bind.

Input Formatting ^

The input supplied to the SNMP functions is designed to be very flexible and allows the user to use shortcuts to apply instances to variables.

Input formatting options for the get,next,walk

Simple format name.instance or oid.instance

 $snmp->get('e','ifIndex.1','ifAdminStatus.1','ifOperStatus.1')
 $snmp->get('e','1.3.6.1.2.1.2.2.1.1.1','1.3.6.1.2.1.2.2.1.7.1','1.3.6.1.2.1.2.2.1.8.1')

Shortcut format instance up front (no instance in mib name or oid

 $snmp->get('e',1,'ifIndex','ifAdminStatus','ifOperStatus')
 $snmp->get('e',1,'1.3.6.1.2.1.2.2.1.1','1.3.6.1.2.1.2.2.1.7','1.3.6.1.2.1.2.2.1.8')

Long format name,instance,name,instance etc of oid,instance,oid,instance etc

 $snmp->get('e','ifIndex',1,'ifAdminStatus',1,'ifOperStatus',1)
 $snmp->get('e','1.3.6.1.2.1.2.2.1.1',1,'1.3.6.1.2.1.2.2.1.7',1,'1.3.6.1.2.1.2.2.1.8',1)

You may also set up an array for any of the above formats and pass the array into the get function as follows:

 @oids = ('ifIndex.1','ifAdminStatus.1','ifOperStatus.1')
 $snmp->get('e',@oids)

Hash like format name => instance or oid => instance

 $interface = 1
 $snmp->get(
           'e',
           ifIndex => $interface,
           ifAdminStatus => $interface,
           ifOperStatus => $interface,
           ifSpeed => $interface,
           )
 or 

 $snmp->get(
           index => $interface,
           ifIndex,
           ifAdminStatus,
           ifOperStatus,
           ifSpeed,
           )

Calling get with dashed options

 @result = $snmp->get(
                     -format => 'ne',
                     -oids => [
                               ifIndex => $interface,
                               ifAdminStatus => $interface,
                               ifOperStatus => $interface,
                               ifSpeed => $interface,
                               ],
                    )
 or 
 @oids = ('ifIndex.1','ifAdminStatus.1','ifOperStatus.1')
 @result = $snmp->get(
                     -format => 'ne',
                     -oids => \@oids,
                     )

Note: When using the dashed option format, you must pass the array by reference as shown above.

Input formats for the set routine

Simple format name.instance,value or oid.instance,value

 $snmp->set('ifAdminStatus.1','up')
 $snmp->set('1.3.6.1.2.1.2.2.1.7.1','up')

Shortcut format instance up front (no instance in mib name or oid

 $snmp->set(1,'ifAdminStatus','up')
 $snmp->set(1,'1.3.6.1.2.1.2.2.1.7','up')

Long format name,instance,value or oid,instance,value

 $snmp->set('ifAdminStatus',1,'up')
 $snmp->set('1.3.6.1.2.1.2.2.1.7',1,'up')

You may also set up an array for any of the above formats and pass the array into the get method as follows:

 @oids = ('ifAdminStatus.1','up')
 $snmp->set(@oids)

Hash like format

 $snmp->set(
           "ifAdminStatus.$interface" => 'up',
           )
 or 

 $snmp->set(
           index => $interface,
           "ifAdminStatus" => 'up',
           )

SNMP Method summary ^

get

The get will do a snmpget and return an array specified by the format statement.

 Usage: @result = $snmp->get('ne','ifAdminStatus.1')
        $result[0] = ifAdminStatus.1
        $result[1] = 'up'

        $result = $snmp->get('e','ifAdminStatus.1')
        Note: As shown above, the result is a scalar if only one value is returned

get_hash

This method will do an snmpget and return a hash. The format for the hash is (value = $hash->{mibname}{index}).

 example: $hash = $snmp->get_hash('ne','ifIndex.1','ifIndex.2',
                                  'ifOperStatus.1','ifOperStatus.2'); 

 $hash->{ifIndex}{1} = 1
 $hash->{ifIndex}{2} = 2
 $hash->{ifOperStatus}{1} = up
 $hash->{ifOperStatus}{2} = up

 Note: Valid format statements for get_hash are 'ne' or 'nv'

get_set_restore

The get_set_restore will get the variable, set it to a range and restore the value

 Usage:  @result = $snmp->get_set_restore('1..10','ifAdminStatus.1');
         where the value '1..10' is the range of values

 Note: The range is specified using .. for ranges and , for individual values. 

next

The next will do a snmpnext and return an array specified by the format statement.

 Usage:  @result = $snmp->next('ne','ifAdminStatus.1')
        $result[0] = ifAdminStatus.2
        $result[1] = 'up'

        $result = $snmp->next('e','ifAdminStatus.1')
        Note: As shown above, the result is a scalar if only one value is returned

ping_check

The ping_check will do a snmpget of uptime and return 1 if device is alive

ping_check_exit

The ping_check will do a snmpget of uptime and exit if not alive

poll_device

The poll_device will loop on the snmpget of uptime command until the device is reachable. The loop will exit once the poll_timeout time is reached (default = 5 minutes).

poll_devices

The poll_devices will do a snmpget of uptime on several devices until the device are reachable. The loop will exit once the poll_timeout time is reached (default = 5 minutes).

 $snmp->poll_devices(@IP_array);
 where @IP_array = array of IP addresses

poll_value

The poll value method will poll a mib variable until it reaches that state and returns the amount of time it took to reach that state

 Usage: $snmp->poll_value(-oid => "ifAdminStatus.$interface",
                         -state => 'up',
                         -timeout => 120,
                         -montime => 5,
                         -delay   => 1)

 or 
  
 $snmp->poll_value(-oid     => "1.3.6.1.2.1.2.2.1.8",
                  -instance => $interface,
                  -state => 'up',
                  -timeout => 120,
                  -montime => 5,
                  -delay   => 1)

or

 use a array ref if you want the polling to stop when the result 
 matches more than one value

 $snmp->poll_value(-oid     => "1.3.6.1.2.1.2.2.1.8",
                  -instance => $interface,
                  -state => ['up','down']
                  -timeout => 120,
                  -montime => 5,
                  -delay   => 1)

 
 Note: You must use the instance when using oids.

set

The set will set a group of variables and return 1 if passed

 Usage:  @result = $snmp->set(
                             index => 1,
                             ifAdminStatus => 'up',
                             )

set_get

The set_get will set a group of variables,get,check and return 1 if passed

 Usage:  @result = $snmp->set(
                             index => 1,
                             ifAdminStatus => 'up',
                             )

walk

The walk will do a snmpwalk and return an array specified by the format statement. It also has a special print option to print out each loop in the walk. This method is capable of doing multivarbind walks.

 Usage: @result = $snmp->walk(-format => 'ne',
                               -oids =>['ifAdminStatus'],
                               -print => 'on');
                           
                  where print = 'on' or 'off'

        or use the shortcut format (Note: print will be disabled by default
                                     
        @result = $snmp->walk('ne','ifAdminStatus');                          

        $result[0] = ifAdminStatus.1
        $result[1] = 'up'
        $result[2] = ifAdminStatus.2
        $result[3] = 'up'
        ...

walk_hash

The walk_hash will do a snmpwalk and return a hash with the value specified by the format. This method is capable of doing multivarbind walks.

 Usage: $result = $snmp->walk_hash('e','ifIndex','ifAdminStatus','ifOperStatus')
        $result->{ifIndex}{1} = 1
        $result->{ifAdminStatus}{1} = 'up'
        $result->{ifOperStatus}{1} = 'up'
        $result->{ifIndex}{2} = 2
        $result->{ifAdminStatus}{2} = 'up'
        $result->{ifOperStatus}{2} = 'up'

 or 
 Usage: $result = $snmp->walk_hash('v','ifIndex','ifAdminStatus','ifOperStatus')
        $result->{ifIndex}{1} = 1
        $result->{ifAdminStatus}{1} = 1
        $result->{ifOperStatus}{1} = 1
        $result->{ifIndex}{2} = 2
        $result->{ifAdminStatus}{2} = 1
        $result->{ifOperStatus}{2} = 1
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