A Net::SNMP object can be created such that it has either ``blocking'' or ``non-blocking'' properties. By default, the methods used to send SNMP messages do not return until the protocol exchange has completed successfully or a timeout period has expired. This behavior gives the object a ``blocking'' property because the flow of the code is stopped until the method returns.
The optional named argument -nonblocking can be passed to the object constructor with a true value to give the object ``non-blocking'' behavior. A method invoked by a non-blocking object queues the SNMP message and returns immediately, allowing the flow of the code to continue. The queued SNMP messages are not sent until an event loop is entered by calling the "snmp_dispatcher()" method. When the SNMP messages are sent, any response to the messages invokes the subroutine defined by the user when the message was originally queued. The event loop exits when all messages have been removed from the queue by either receiving a response, or by exceeding the number of retries at the Transport Layer.
The hash reference returned by a SNMP protocol exchange points to a hash constructed from the VarBindList contained in the SNMP response message. The hash is created using the ObjectName and the ObjectSyntax pairs in the VarBindList. The keys of the hash consist of the OBJECT IDENTIFIERs in dotted notation corresponding to each ObjectName in the VarBindList. The value of each hash entry is set equal to the value of the corresponding ObjectSyntax. This hash reference can also be retrieved using the "var_bind_list()" method.
The contents of the VarBindList contained in the SNMP response message can be retrieved by calling the "var_bind_list()" method using the object reference passed as the first argument to the callback. The value returned by the "var_bind_list()" method is a hash reference created using the ObjectName and the ObjectSyntax pairs in the VarBindList. The keys of the hash consist of the OBJECT IDENTIFIERs in dotted notation corresponding to each ObjectName in the VarBindList. The value of each hash entry is set equal to the value of the corresponding ObjectSyntax. The undefined value is returned if there has been a failure and the "error()" method may be used to determine the reason.
$object->method(-argument => $value);
However, the IO:: style is also allowed:
$object->method(Argument => $value);
When the -callback argument only contains a subroutine reference, the subroutine is evaluated passing a reference to the original Net::SNMP object as the only parameter. If the -callback argument was defined as an array reference, all elements in the array are passed to subroutine after the reference to the Net::SNMP object. The first element, which is required to be a reference to a subroutine, is removed before the remaining arguments are passed to that subroutine.
Once one method is invoked with the -callback argument, this argument stays with the object and is used by any further calls to methods using the -callback option if the argument is absent. The undefined value may be passed to the -callback argument to delete the callback.
NOTE: The subroutine being passed with the -callback named argument should not cause blocking itself. This will cause all the actions in the event loop to be stopped, defeating the non-blocking property of the Net::SNMP module.
($session, $error) = Net::SNMP->session(
[-hostname => $hostname,]
[-port => $port,]
[-localaddr => $localaddr,]
[-localport => $localport,]
[-nonblocking => $boolean,]
[-version => $version,]
[-domain => $domain,]
[-timeout => $seconds,]
[-retries => $count,]
[-maxmsgsize => $octets,]
[-translate => $translate,]
[-debug => $bitmask,]
[-community => $community,] # v1/v2c
[-username => $username,] # v3
[-authkey => $authkey,] # v3
[-authpassword => $authpasswd,] # v3
[-authprotocol => $authproto,] # v3
[-privkey => $privkey,] # v3
[-privpassword => $privpasswd,] # v3
[-privprotocol => $privproto,] # v3
);
This is the constructor for Net::SNMP objects. In scalar context, a reference to a new Net::SNMP object is returned if the creation of the object is successful. In list context, a reference to a new Net::SNMP object and an empty error message string is returned. If a failure occurs, the object reference is returned as the undefined value. The error string may be used to determine the cause of the error.
Most of the named arguments passed to the constructor define basic attributes for the object and are not modifiable after the object has been created. The -timeout, -retries, -maxmsgsize, -translate, and -debug arguments are modifiable using an accessor method. See their corresponding method definitions for a complete description of their usage, default values, and valid ranges.
The transport address of the destination SNMP device can be specified using the -hostname argument. This argument is optional and defaults to ``localhost''. The destination port number can be specified as part of the transport address or by using the -port argument. Either a numeric port number or a textual service name can be specified. A numeric port number in parentheses can optionally follow the service name. This port number will be used if the service name cannot be resolved. If the destination port number is not specified, the well-known SNMP port number 161 is used.
By default the source transport address and port number are assigned dynamically by the local device on which the Net::SNMP module is being used. This dynamic assignment can be overridden by using the -localaddr and -localport arguments. These arguments accept the same values as the -hostname and -port arguments respectively. The resolved address must correspond to a valid address of an interface on the local device.
When using an IPv4 Transport Domain, the transport address can be specified as either an IP network hostname or an IPv4 address in standard dotted notation. The port information can be optionally appended to the hostname or address delimited by a colon. The accepted IPv4 transport address formats are "address", "address:port", "hostname", and "hostname:port".
When using an IPv6 Transport Domain, the transport address can be specified as an IP hostname (which will be looked up as a DNS quad-A record) or an IPv6 address in presentation format. The port information can optionally be included following a colon after the hostname or address. When including this information after an IPv6 address, the address must be enclosed in square brackets. The scope zone index (described in RFC 4007) can be specified after the address as a decimal value delimited by a percent sign. The accepted transport address formats for IPv6 are "address", "address%zone", "[address]:port", "[address%zone]:port", "hostname", and "hostname:port".
The Security Model used by the Net::SNMP object is based on the SNMP version associated with the object. If the SNMP version is SNMPv1 or SNMPv2c a Community-based Security Model will be used, while the User-based Security Model (USM) will be used if the version is SNMPv3.
Different levels of security are allowed by the User-based Security Model which address authentication and privacy concerns. A SNMPv3 Net::SNMP object will derive the security level (securityLevel) based on which of the following arguments are specified.
By default a securityLevel of 'noAuthNoPriv' is assumed. If the -authkey or -authpassword arguments are specified, the securityLevel becomes 'authNoPriv'. The -authpassword argument expects a string which is at least 1 octet in length. Optionally, the -authkey argument can be used so that a plain text password does not have to be specified in a script. The -authkey argument expects a hexadecimal string produced by localizing the password with the authoritativeEngineID for the specific destination device. The "snmpkey" utility included with the distribution can be used to create the hexadecimal string (see snmpkey).
Two different hash algorithms are defined by SNMPv3 which can be used by the Security Model for authentication. These algorithms are HMAC-MD5-96 ``MD5'' (RFC 1321) and HMAC-SHA-96 ``SHA-1'' (NIST FIPS PUB 180-1). The default algorithm used by the module is HMAC-MD5-96. This behavior can be changed by using the -authprotocol argument. This argument expects either the string 'md5' or 'sha' to be passed to modify the hash algorithm.
By specifying the arguments -privkey or -privpassword the securityLevel associated with the object becomes 'authPriv'. According to SNMPv3, privacy requires the use of authentication. Therefore, if either of these two arguments are present and the -authkey or -authpassword arguments are missing, the creation of the object fails. The -privkey and -privpassword arguments expect the same input as the -authkey and -authpassword arguments respectively.
The User-based Security Model described in RFC 3414 defines a single encryption protocol to be used for privacy. This protocol, CBC-DES ``DES'' (NIST FIPS PUB 46-1), is used by default or if the string 'des' is passed to the -privprotocol argument. The module also supports RFC 3826 which describes the use of CFB128-AES-128 ``AES'' (NIST FIPS PUB 197) in the USM. The AES encryption protocol can be selected by passing 'aes' or 'aes128' to the -privprotocol argument. By working with the Extended Security Options Consortium <http://www.snmp.com/protocol/eso.shtml>, the module also supports CBC-3DES-EDE ``Triple-DES'' (NIST FIPS 46-3) in the User-based Security Model. This is defined in the draft <http://www.snmp.com/eso/draft-reeder-snmpv3-usm-3desede-00.txt>. The Triple-DES encryption protocol can be selected using the -privprotocol argument with the string '3des' or '3desede'.
$session->close();
This method clears the Transport Domain and any errors associated with the object. Once closed, the Net::SNMP object can no longer be used to send or receive SNMP messages.
$session->snmp_dispatcher();
This method enters the event loop associated with non-blocking Net::SNMP objects. The method exits when all queued SNMP messages have received a response or have timed out at the Transport Layer. This method is also exported as the stand alone function "snmp_dispatcher()" by default (see ``EXPORTS'').
$result = $session->get_request(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-varbindlist => \@oids,
);
This method performs a SNMP get-request query to gather data from the remote agent on the host associated with the Net::SNMP object. The message is built using the list of OBJECT IDENTIFIERs in dotted notation passed to the method as an array reference using the -varbindlist argument. Each OBJECT IDENTIFIER is placed into a single SNMP GetRequest-PDU in the same order that it held in the original list.
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
$result = $session->get_next_request(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-varbindlist => \@oids,
);
This method performs a SNMP get-next-request query to gather data from the remote agent on the host associated with the Net::SNMP object. The message is built using the list of OBJECT IDENTIFIERs in dotted notation passed to the method as an array reference using the -varbindlist argument. Each OBJECT IDENTIFER is placed into a single SNMP GetNextRequest-PDU in the same order that it held in the original list.
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
$result = $session->set_request(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-varbindlist => \@oid_value,
);
This method is used to modify data on the remote agent that is associated with the Net::SNMP object using a SNMP set-request. The message is built using a list of values consisting of groups of an OBJECT IDENTIFIER, an object type, and the actual value to be set. This list is passed to the method as an array reference using the -varbindlist argument. The OBJECT IDENTIFIERs in each trio are to be in dotted notation. The object type is an octet corresponding to the ASN.1 type of value that is to be set. Each of the supported ASN.1 types have been defined and are exported by the package by default (see ``EXPORTS'').
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
$result = $session->trap(
[-delay => $seconds,] # non-blocking
[-enterprise => $oid,]
[-agentaddr => $ipaddress,]
[-generictrap => $generic,]
[-specifictrap => $specific,]
[-timestamp => $timeticks,]
-varbindlist => \@oid_value,
);
This method sends a SNMP trap to the remote manager associated with the Net::SNMP object. All arguments are optional and will be given the following defaults in the absence of a corresponding named argument:
A true value is returned when the method is successful. The undefined value is returned when a failure has occurred. The "error()" method can be used to determine the cause of the failure. Since there are no acknowledgements for Trap-PDUs, there is no way to determine if the remote host actually received the trap.
NOTE: When the object is in non-blocking mode, the trap is not sent until the event loop is entered and no callback is ever executed.
NOTE: This method can only be used when the version of the object is set to SNMPv1.
$result = $session->get_bulk_request(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
[-nonrepeaters => $non_reps,]
[-maxrepetitions => $max_reps,]
-varbindlist => \@oids,
);
This method performs a SNMP get-bulk-request query to gather data from the remote agent on the host associated with the Net::SNMP object. All arguments are optional except -varbindlist and will be given the following defaults in the absence of a corresponding named argument:
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
NOTE: This method can only be used when the version of the object is set to SNMPv2c or SNMPv3.
$result = $session->inform_request(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-varbindlist => \@oid_value,
);
This method is used to provide management information to the remote manager associated with the Net::SNMP object using an inform-request. The message is built using a list of values consisting of groups of an OBJECT IDENTIFIER, an object type, and the actual value to be identified. This list is passed to the method as an array reference using the -varbindlist argument. The OBJECT IDENTIFIERs in each trio are to be in dotted notation. The object type is an octet corresponding to the ASN.1 type of value that is to be identified. Each of the supported ASN.1 types have been defined and are exported by the package by default (see ``EXPORTS'').
The first two variable-bindings fields in the inform-request are specified by SNMPv2 and should be:
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
NOTE: This method can only be used when the version of the object is set to SNMPv2c or SNMPv3.
$result = $session->snmpv2_trap(
[-delay => $seconds,] # non-blocking
-varbindlist => \@oid_value,
);
This method sends a snmpV2-trap to the remote manager associated with the Net::SNMP object. The message is built using a list of values consisting of groups of an OBJECT IDENTIFIER, an object type, and the actual value to be identified. This list is passed to the method as an array reference using the -varbindlist argument. The OBJECT IDENTIFIERs in each trio are to be in dotted notation. The object type is an octet corresponding to the ASN.1 type of value that is to be identified. Each of the supported ASN.1 types have been defined and are exported by the package by default (see ``EXPORTS'').
The first two variable-bindings fields in the snmpV2-trap are specified by SNMPv2 and should be:
A true value is returned when the method is successful. The undefined value is returned when a failure has occurred. The "error()" method can be used to determine the cause of the failure. Since there are no acknowledgements for SNMPv2-Trap-PDUs, there is no way to determine if the remote host actually received the snmpV2-trap.
NOTE: When the object is in non-blocking mode, the snmpV2-trap is not sent until the event loop is entered and no callback is ever executed.
NOTE: This method can only be used when the version of the object is set to SNMPv2c. SNMPv2-Trap-PDUs are supported by SNMPv3, but require the sender of the message to be an authoritative SNMP engine which is not currently supported by the Net::SNMP module.
$result = $session->get_table(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-baseoid => $oid,
[-maxrepetitions => $max_reps,] # v2c/v3
);
This method performs repeated SNMP get-next-request or get-bulk-request (when using SNMPv2c or SNMPv3) queries to gather data from the remote agent on the host associated with the Net::SNMP object. The first message sent is built using the OBJECT IDENTIFIER in dotted notation passed to the method by the -baseoid argument. Repeated SNMP requests are issued until the OBJECT IDENTIFIER in the response is no longer a child of the base OBJECT IDENTIFIER.
The -maxrepetitions argument can be used to specify the max-repetitions value that is passed to the get-bulk-requests when using SNMPv2c or SNMPv3. If this argument is not present, a value is calculated based on the maximum message size for the Net::SNMP object. If the value is set to 1 or less, get-next-requests will be used for the queries instead of get-bulk-requests.
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
WARNING: Results from this method can become very large if the base OBJECT IDENTIFIER is close to the root of the SNMP MIB tree.
$result = $session->get_entries(
[-callback => sub {},] # non-blocking
[-delay => $seconds,] # non-blocking
[-contextengineid => $engine_id,] # v3
[-contextname => $name,] # v3
-columns => \@columns,
[-startindex => $start,]
[-endindex => $end,]
[-maxrepetitions => $max_reps,] # v2c/v3
);
This method performs repeated SNMP get-next-request or get-bulk-request (when using SNMPv2c or SNMPv3) queries to gather data from the remote agent on the host associated with the Net::SNMP object. Each message specifically requests data for each OBJECT IDENTIFIER specified in the -columns array. The OBJECT IDENTIFIERs must correspond to column entries for a conceptual row in a table. They may however be columns in different tables as long as each table is indexed the same way. The optional -startindex and -endindex arguments may be specified to limit the query to specific rows in the table(s).
The -startindex can be specified as a single decimal value or in dotted notation if the index associated with the entry so requires. If the -startindex is specified, it will be include as part of the query results. If no -startindex is specified, the first request message will be sent without an index. To insure that the -startindex is included, the last sub-identifier in the index is decremented by one. If the last sub-identifier has a value of zero, the sub-identifier is removed from the index.
The optional -endindex argument can be specified as a single decimal value or in dotted notation. If the -endindex is specified, it will be included as part of the query results. If no -endindex is specified, repeated SNMP requests are issued until the response no longer returns entries matching any of the columns specified in the -columns array.
The -maxrepetitions argument can be used to specify the max-repetitions value that is passed to the get-bulk-requests when using SNMPv2c or SNMPv3. If this argument is not present, a value is calculated based on the maximum message size of the object and the number of columns specified in the -columns array. If the value is set to 1 or less, get-next-requests will be used for the queries instead of get-bulk-requests.
A reference to a hash is returned in blocking mode which contains the contents of the VarBindList. In non-blocking mode, a true value is returned when no error has occurred. In either mode, the undefined value is returned when an error has occurred. The "error()" method may be used to determine the cause of the failure.
$rfc_version = $session->version();
This method returns the current value for the SNMP version associated with the object. The returned value is the corresponding version number defined by the RFCs for the protocol version field (i.e. SNMPv1 == 0, SNMPv2c == 1, and SNMPv3 == 3). The RFC versions are defined as constant by the module and can be exported by request (see ``EXPORTS'').
$error_message = $session->error();
This method returns a text string explaining the reason for the last error. An empty string is returned if no error has occurred.
$hostname = $session->hostname();
This method returns the parsed hostname string that is associated with the object. Any port information and formatting that can be included with the corresponding "session()" constructor argument will be stripped and not included as part of the returned string.
$error_status = $session->error_status();
This method returns the numeric value of the error-status contained in the last SNMP message received by the object.
$error_index = $session->error_index();
This method returns the numeric value of the error-index contained in the last SNMP message received by the object.
$values = $session->var_bind_list();
This method returns a hash reference created using the ObjectName and the ObjectSyntax pairs in the VarBindList of the last SNMP message received by the object. The keys of the hash consist of the OBJECT IDENTIFIERs in dotted notation corresponding to each ObjectName in the VarBindList. If any of the OBJECT IDENTIFIERs passed to the request method began with a leading dot, all of the OBJECT IDENTIFIER hash keys will be prefixed with a leading dot. If duplicate OBJECT IDENTIFIERs are present in the VarBindList they will be padded with spaces to make them an unique hash key. The value of each hash entry is set equal to the value of the corresponding ObjectSyntax. The undefined value is returned if there has been a failure.
@names = $session->var_bind_names();
This method returns an array containing the OBJECT IDENTIFIERs corresponding to the ObjectNames in the VarBindList in the order that they were received in the last SNMP message. The entries in the array will map directly to the keys in the hash reference returned by the methods that perform SNMP message exchanges and by the "var_bind_list()" and "var_bind_types()" methods. The array returned for the convenience methods "get_table()" and "get_entries()" will be in lexicographical order. An empty array is returned if there has been a failure.
$types = $session->var_bind_types();
This method returns a hash reference created using the ObjectName and the ASN.1 type of the ObjectSyntax in the VarBindList of the last SNMP message received by the object. The keys of the hash consist of the OBJECT IDENTIFIERs in dotted notation corresponding to each ObjectName in the VarBindList. The value of each hash entry is set equal to the ASN.1 type of the corresponding ObjectSyntax. Constants for the supported ASN.1 types have been defined and are exported by the package by default (see ``EXPORTS''). The undefined value is returned if there has been a failure.
$seconds = $session->timeout([$seconds]);
This method returns the current value for the Transport Layer timeout for the Net::SNMP object. This value is the number of seconds that the object will wait for a response from the agent on the remote host. The default timeout is 5.0 seconds.
If a parameter is specified, the timeout for the object is set to the provided value if it falls within the range 1.0 to 60.0 seconds. The undefined value is returned upon an error and the "error()" method may be used to determine the cause.
$count = $session->retries([$count]);
This method returns the current value for the number of times to retry sending a SNMP message to the remote host. The default number of retries is 1.
If a parameter is specified, the number of retries for the object is set to the provided value if it falls within the range 0 to 20. The undefined value is returned upon an error and the "error()" method may be used to determine the cause.
$octets = $session->max_msg_size([$octets]);
This method returns the current value for the maximum message size (maxMsgSize) for the Net::SNMP object. This value is the largest message size in octets that can be prepared or processed by the object. The default maxMsgSize is 1472 octets for UDP/IPv4, 1452 octets for UDP/IPv6, 1460 octets for TCP/IPv4, and 1440 octets for TCP/IPv6.
If a parameter is specified, the maxMsgSize is set to the provided value if it falls within the range 484 to 65535 octets. The undefined value is returned upon an error and the "error()" method may be used to determine the cause.
NOTE: When using SNMPv3, the maxMsgSize is actually contained in the SNMP message (as msgMaxSize). If the value received from a remote device is less than the current maxMsgSize, the size is automatically adjusted to be the lower value.
$mask = $session->translate([
$mode |
[ # Perl anonymous ARRAY reference
['-all' => $mode0,]
['-octetstring' => $mode1,]
['-null' => $mode2,]
['-timeticks' => $mode3,]
['-opaque' => $mode4,]
['-nosuchobject' => $mode5,]
['-nosuchinstance' => $mode6,]
['-endofmibview' => $mode7,]
['-unsigned' => $mode8]
]
]);
When the object decodes the GetResponse-PDU that is returned in response to a SNMP message, certain values are translated into a more ``human readable'' form. By default the following translations occur:
The "translate()" method can be invoked with two different types of arguments.
If the argument passed is any Perl variable type except an array reference, the translation mode for all ASN.1 types is set to either enabled or disabled, depending on the value of the passed parameter. Any value that Perl would treat as a true value will set the mode to be enabled for all types, while a false value will disable translation for all types.
A reference to an array can be passed to the "translate()" method in order to define the translation mode on a per ASN.1 type basis. The array is expected to contain a list of named argument pairs for each ASN.1 type that is to be modified. The arguments in the list are applied in the order that they are passed in via the array. Arguments at the end of the list supercede those passed earlier in the list. The argument ``-all'' can be used to specify that the mode is to apply to all ASN.1 types. Only the arguments for the ASN.1 types that are to be modified need to be included in the list.
The "translate()" method returns a bit mask indicating which ASN.1 types are to be translated. Definitions of the bit to ASN.1 type mappings can be exported using the :translate tag (see ``EXPORTS''). The undefined value is returned upon an error and the "error()" method may be used to determine the cause.
$mask = $session->debug([$mask]);
This method is used to enable or disable debugging for the Net::SNMP module. Debugging can be enabled on a per component level as defined by a bit mask passed to the "debug()" method. The bit mask is broken up as follows:
Symbols representing these bit mask values are defined by the module and can be exported using the :debug tag (see ``EXPORTS''). If a non-numeric value is passed to the "debug()" method, it is evaluated in boolean context. Debugging for all of the components is then enabled or disabled based on the resulting truth value.
The current debugging mask is returned by the method. Debugging can also be enabled using the stand alone function "snmp_debug()". This function can be exported by request (see ``EXPORTS'').
$value = oid_base_match($base_oid, $oid);
This function takes two OBJECT IDENTIFIERs in dotted notation and returns a true value (i.e. 0x1) if the second OBJECT IDENTIFIER is equal to or is a child of the first OBJECT IDENTIFIER in the SNMP Management Information Base (MIB). This function can be used in conjunction with the "get-next-request()" or "get-bulk-request()" methods to determine when a OBJECT IDENTIFIER in the GetResponse-PDU is no longer in the desired MIB tree branch.
$cmp = oid_lex_cmp($oid1, $oid2);
This function takes two OBJECT IDENTIFIERs in dotted notation and returns one of the values 1, 0, -1 if $oid1 is respectively lexicographically greater, equal, or less than $oid2.
@sorted_oids = oid_lex_sort(@oids);
This function takes a list of OBJECT IDENTIFIERs in dotted notation and returns the listed sorted in lexicographical order.
$text = snmp_type_ntop($type);
This function takes an ASN.1 type octet and returns a text string suitable for presentation. Some ASN.1 type definitions map to the same octet value when encoded. This method cannot distinguish between these multiple mappings and the most basic type name will be returned.
$time = ticks_to_time($timeticks);
This function takes an ASN.1 TimeTicks value and returns a string representing the time defined by the value. The TimeTicks value is expected to be a non-negative integer value representing the time in hundredths of a second since some epoch. The returned string will display the time in days, hours, and seconds format according to the value of the TimeTicks argument.
#! /usr/local/bin/perl
use strict;
use warnings;
use Net::SNMP;
my $OID_sysUpTime = '1.3.6.1.2.1.1.3.0';
my ($session, $error) = Net::SNMP->session(
-hostname => shift || 'localhost',
-community => shift || 'public',
);
if (!defined $session) {
printf "ERROR: %s.\n", $error;
exit 1;
}
my $result = $session->get_request(-varbindlist => [ $OID_sysUpTime ],);
if (!defined $result) {
printf "ERROR: %s.\n", $session->error();
$session->close();
exit 1;
}
printf "The sysUpTime for host '%s' is %s.\n",
$session->hostname(), $result->{$OID_sysUpTime};
$session->close();
exit 0;
#! /usr/local/bin/perl
use strict;
use warnings;
use Net::SNMP;
my $OID_sysContact = '1.3.6.1.2.1.1.4.0';
my ($session, $error) = Net::SNMP->session(
-hostname => 'myv3host.example.com',
-version => 'snmpv3',
-username => 'myv3Username',
-authprotocol => 'sha1',
-authkey => '0x6695febc9288e36282235fc7151f128497b38f3f',
-privprotocol => 'des',
-privkey => '0x6695febc9288e36282235fc7151f1284',
);
if (!defined $session) {
printf "ERROR: %s.\n", $error;
exit 1;
}
my $result = $session->set_request(
-varbindlist => [ $OID_sysContact, OCTET_STRING, 'Help Desk x911' ],
);
if (!defined $result) {
printf "ERROR: %s.\n", $session->error();
$session->close();
exit 1;
}
printf "The sysContact for host '%s' was set to '%s'.\n",
$session->hostname(), $result->{$OID_sysContact};
$session->close();
exit 0;
#! /usr/local/bin/perl
use strict;
use warnings;
use Net::SNMP qw(:snmp);
my $OID_ifTable = '1.3.6.1.2.1.2.2';
my $OID_ifPhysAddress = '1.3.6.1.2.1.2.2.1.6';
my ($session, $error) = Net::SNMP->session(
-hostname => shift || 'localhost',
-community => shift || 'public',
-nonblocking => 1,
-translate => [-octetstring => 0],
-version => 'snmpv2c',
);
if (!defined $session) {
printf "ERROR: %s.\n", $error;
exit 1;
}
my %table; # Hash to store the results
my $result = $session->get_bulk_request(
-varbindlist => [ $OID_ifTable ],
-callback => [ \&table_callback, \%table ],
-maxrepetitions => 10,
);
if (!defined $result) {
printf "ERROR: %s\n", $session->error();
$session->close();
exit 1;
}
# Now initiate the SNMP message exchange.
snmp_dispatcher();
$session->close();
# Print the results, specifically formatting ifPhysAddress.
for my $oid (oid_lex_sort(keys %table)) {
if (!oid_base_match($OID_ifPhysAddress, $oid)) {
printf "%s = %s\n", $oid, $table{$oid};
} else {
printf "%s = %s\n", $oid, unpack 'H*', $table{$oid};
}
}
exit 0;
sub table_callback
{
my ($session, $table) = @_;
my $list = $session->var_bind_list();
if (!defined $list) {
printf "ERROR: %s\n", $session->error();
return;
}
# Loop through each of the OIDs in the response and assign
# the key/value pairs to the reference that was passed with
# the callback. Make sure that we are still in the table
# before assigning the key/values.
my @names = $session->var_bind_names();
my $next = undef;
while (@names) {
$next = shift @names;
if (!oid_base_match($OID_ifTable, $next)) {
return; # Table is done.
}
$table->{$next} = $list->{$next};
}
# Table is not done, send another request, starting at the last
# OBJECT IDENTIFIER in the response. No need to include the
# calback argument, the same callback that was specified for the
# original request will be used.
my $result = $session->get_bulk_request(
-varbindlist => [ $next ],
-maxrepetitions => 10,
);
if (!defined $result) {
printf "ERROR: %s.\n", $session->error();
}
return;
}
#! /usr/local/bin/perl
use strict;
use warnings;
use Net::SNMP;
my $OID_sysUpTime = '1.3.6.1.2.1.1.3.0';
my $OID_sysContact = '1.3.6.1.2.1.1.4.0';
my $OID_sysLocation = '1.3.6.1.2.1.1.6.0';
# Hash of hosts and location data.
my %host_data = (
'10.1.1.2' => 'Building 1, Second Floor',
'10.2.1.1' => 'Building 2, First Floor',
'localhost' => 'Right here!',
);
# Create a session for each host and queue a get-request for sysUpTime.
for my $host (keys %host_data) {
my ($session, $error) = Net::SNMP->session(
-hostname => $host,
-community => 'private',
-nonblocking => 1,
);
if (!defined $session) {
printf "ERROR: Failed to create session for host '%s': %s.\n",
$host, $error;
next;
}
my $result = $session->get_request(
-varbindlist => [ $OID_sysUpTime ],
-callback => [ \&get_callback, $host_data{$host} ],
);
if (!defined $result) {
printf "ERROR: Failed to queue get request for host '%s': %s.\n",
$session->hostname(), $session->error();
}
}
# Now initiate the SNMP message exchange.
snmp_dispatcher();
exit 0;
sub get_callback
{
my ($session, $location) = @_;
my $result = $session->var_bind_list();
if (!defined $result) {
printf "ERROR: Get request failed for host '%s': %s.\n",
$session->hostname(), $session->error();
return;
}
printf "The sysUpTime for host '%s' is %s.\n",
$session->hostname(), $result->{$OID_sysUpTime};
# Now set the sysContact and sysLocation for the host.
$result = $session->set_request(
-varbindlist =>
[
$OID_sysContact, OCTET_STRING, 'Help Desk x911',
$OID_sysLocation, OCTET_STRING, $location,
],
-callback => \&set_callback,
);
if (!defined $result) {
printf "ERROR: Failed to queue set request for host '%s': %s.\n",
$session->hostname(), $session->error();
}
return;
}
sub set_callback
{
my ($session) = @_;
my $result = $session->var_bind_list();
if (defined $result) {
printf "The sysContact for host '%s' was set to '%s'.\n",
$session->hostname(), $result->{$OID_sysContact};
printf "The sysLocation for host '%s' was set to '%s'.\n",
$session->hostname(), $result->{$OID_sysLocation};
} else {
printf "ERROR: Set request failed for host '%s': %s.\n",
$session->hostname(), $session->error();
}
return;
}
The Abstract Syntax Notation One (ASN.1) encode and decode methods were originally derived by example from the CMU SNMP package whose copyright follows: Copyright (c) 1988, 1989, 1991, 1992 by Carnegie Mellon University. All rights reserved.
This program is free software; you may redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.