TrapReceiver(3) User Contributed Perl Documentation TrapReceiver(3)NAMENetSNMP::TrapReceiver - Embedded perl trap handling for Net-SNMP's
snmptrapd
SYNOPSIS
Put the following lines in your snmptrapd.conf file:
perl NetSNMP::TrapReceiver::register("trapOID", \&myfunc);
ABSTRACT
The NetSNMP::TrapReceiver module is used to register perl subroutines
into the Net-SNMP snmptrapd process. Net-SNMP MUST have been config‐
ured using --enable-embedded-perl. Registration of functions is then
done through the snmptrapd.conf configuration file. This module can
NOT be used in a normal perl script to receive traps. It is intended
solely for embedded use within the snmptrapd demon.
DESCRIPTION
Within the snmptrapd.conf file, the keyword "perl" may be used to call
any perl expression and using this ability, you can use the Net‐
SNMP::TrapReceiver module to register functions which will be called
every time a given notification (a trap or an inform) is received.
Registered functions are called with 2 arguments. The first is a ref‐
erence to a hash containing information about how the trap was received
(what version of the SNMP protocol was used, where it came from, what
SNMP user name or community name it was sent under, etc). The second
argument is a reference to an array containing the variable bindings
(OID and value information) that define the noification itself. Each
variable is itself a reference to an array containing three values: a
NetSNMP::OID object, the value that came associated with it, and the
value's numeric type (see NetSNMP::ASN for further details on SNMP typ‐
ing information).
Subroutines are registered using the NetSNMP::TrapReceiver::register
function, which takes two arguments. The first is a string describing
the notification you want to register for (such as "linkUp" or
"MyMIB::MyTrap" or ".1.3.6.1.4.1.2021...."). Two special keywords can
be used in place of an OID: "default" and "all". The "default" keyword
indicates you want your handler to be called in the case where no other
handlers are called. The "all" keyword indicates that the handler
should ALWAYS be called for every notification.
EXAMPLE
As an example, put the following code into a file (say
"/usr/local/share/snmp/mytrapd.pl"):
#!/usr/bin/perl
sub my_receiver {
print "********** PERL RECEIVED A NOTIFICATION:\n";
# print the PDU info (a hash reference)
print "PDU INFO:\n";
foreach my $k(keys(%{$_[0]})) {
printf " %-30s %s\n", $k, $_[0]{$k};
}
# print the variable bindings:
print "VARBINDS:\n";
foreach my $x (@{$_[1]}) {
printf " %-30s type=%-2d value=%s\n", $x->[0], $x->[2], $x->[1];
}
}
NetSNMP::TrapReceiver::register("all", \&my_receiver) ⎪⎪
warn "failed to register our perl trap handler\n";
print STDERR "Loaded the example perl snmptrapd handler\n";
Then, put the following line in your snmprapd.conf file:
perl do "/usr/local/share/snmp/mytrapd.pl";
Start snmptrapd (as root, and the following other opions make it stay
in the foreground and log to stderr):
snmptrapd -f -Le
You should see it start up and display the final message from the end
of the above perl script:
Loaded the perl snmptrapd handler
2004-02-11 10:08:45 NET-SNMP version 5.2 Started.
Then, if you send yourself a fake trap using the following example com‐
mand:
snmptrap -v 2c -c mycommunity localhost 0 linkUp ifIndex.1 i 1 \
ifAdminStatus.1 i up ifOperStatus.1 i up ifDescr s eth0
You should see the following output appear from snmptrapd as your perl
code gets executed:
********** PERL RECEIVED A NOTIFICATION:
PDU INFO:
notificationtype TRAP
receivedfrom 127.0.0.1
version 1
errorstatus 0
messageid 0
community mycommunity
transactionid 2
errorindex 0
requestid 765160220
VARBINDS:
sysUpTimeInstance type=67 value=0:0:00:00.00
snmpTrapOID.0 type=6 value=linkUp
ifIndex.1 type=2 value=1
ifAdminStatus.1 type=2 value=1
ifOperStatus.1 type=2 value=1
ifDescr type=4 value="eth0"
EXPORT
None by default.
# =head2 Exportable constants
# NETSNMPTRAPD_AUTH_HANDLER # NETSNMPTRAPD_HANDLER_BREAK # NETSN‐
MPTRAPD_HANDLER_FAIL # NETSNMPTRAPD_HANDLER_FINISH # NETSN‐
MPTRAPD_HANDLER_OK # NETSNMPTRAPD_POST_HANDLER # NETSN‐
MPTRAPD_PRE_HANDLER
SEE ALSO
NetSNMP::OID, NetSNMP::ASN
snmptrapd.conf(5) for configuring the Net-SNMP trap receiver.
snmpd.conf(5) for configuring the Net-SNMP snmp agent for sending
traps.
http://www.Net-SNMP.org/
AUTHOR
W. Hardaker, <hardaker@users.sourceforge.net>
COPYRIGHT AND LICENSE
Copyright 2004 by W. Hardaker
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.8.8 2006-06-30 TrapReceiver(3)
