#!/usr/bin/perl
###
### Copyright (C) 2016 Alexander Gall <gall@switch.ch>
###
### This program is free software: you can redistribute it and/or
### modify it under the terms of the GNU General Public License as
### published by the Free Software Foundation, either version 3 of the
### License, or (at your option) any later version.
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
### General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with this program.  If not, see <http://www.gnu.org/licenses/>.

use strict;
use warnings;
use Getopt::Long;
use Snabb::SNMP::Agent qw(%persistent_ifIndex %compound_scalar_handlers $sysUpTime);
my %opt = ( 'check-interval' => 5,
            'shmem-dir' => '/var/lib/snabb/shmem', );

sub usage() {
  print <<"EOF";
usage: $0 --ifindex=<file>
EOF
  exit(1);
}

sub ifTable_indexer($$$) {
  ## Force persistent ifIndex based on ifDescr
  my ($oid, $table_oid, $segment) = @_;
  my $ifDescr_obj = $segment->{objs}{ifDescr};
  defined $ifDescr_obj or die
    "ifTable IID indexer: no ifDescr present for $segment->{name}";
  tie my $ifDescr, 'Snabb::SNMP::Tie::OCTETSTR', $segment,
    'ifDescr';
  my $ifIndex = $persistent_ifIndex{$ifDescr};
  defined $ifIndex or die
    "ifTable IID indexer: unknown interface $ifDescr";
  return($oid.".".$ifIndex);
}

my %subtrees =
  ( interfaces =>
    { tables =>
      { scalars =>
	{ handlers =>
	  { ifNumber =>
	    { compound_handler => sub {
		return scalar(keys(%persistent_ifIndex));
	      }
	    },
	  },
	},
	ifTable => { indexer => \&ifTable_indexer },
      },
    },

    ifMIB =>
    { tables =>
      { scalars =>
	{ handlers =>
	  { ifTableLastChange =>
	    { compound_handler => sub {
		return $sysUpTime;
	      }
	    },
	  },
	},
	ifXTable => { indexer => \&ifTable_indexer },
      },
    },
  );

GetOptions(\%opt, "check-interval=i",
           "ifindex=s", "shmem-dir=s") or usage();
defined $opt{ifindex} or usage();
Snabb::SNMP::Agent::start({ name => "interface",
                            subtrees => \%subtrees,
			    check_interval => $opt{'check-interval'},
			    if_index => $opt{ifindex},
                            mibs_dirs => '',
                            mibs => '',
                            shmem_dir => $opt{'shmem-dir'},
			  });

## Not reached

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## mode: CPerl
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