From 9e2b06aae8530bfe4ea28e1cfcc5bf8d1598cdb4 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sun, 28 Jan 2018 22:17:35 +0100
Subject: [PATCH] show-switch: --force-v1, .1d FDB

---
 show-switch | 55 +++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 41 insertions(+), 14 deletions(-)

diff --git a/show-switch b/show-switch
index 1033759..0e23fdc 100755
--- a/show-switch
+++ b/show-switch
@@ -9,16 +9,26 @@ use Getopt::Long;
 use List::Util;
 
 sub usage {
-	die "Usage: $0 [--debug] [--mac] [--allmac] <ip-addr>\n";
+	die <<AMEN ;
+Usage: $0 [<options>] <ip-addr>
+
+Options:
+--debug		Show debugging outputs
+--mac		Show one MAC address learned per port
+--allmac	Show all MAC addresses learned per port
+--force-v1	Use SNMPv1 (work-around for buggy switches)
+AMEN
 }
 
 my $debug = 0;
 my $mac = 0;
 my $all_mac = 0;
+my $force_v1 = 0;
 GetOptions(
 	'debug' => \$debug,
 	'mac' => \$mac,
 	'allmac' => \$all_mac,
+	'force-v1' => \$force_v1,
 ) or usage;
 
 @ARGV == 1 or usage;
@@ -39,7 +49,7 @@ my $t_norm = attr("sgr0");
 
 my ($snmp, $err) = Net::SNMP->session(
 	-hostname => $switch_ip,
-	-version => '2c',
+	-version => ($force_v1 ? '1' : '2c'),
 	-community => $community,
 );
 $snmp or die "Cannot establish session: $err\n";
@@ -130,23 +140,40 @@ print Dumper($if_table) if $debug;
 
 if ($mac) {
 	my $OID_1qTpFdbTable = '1.3.6.1.2.1.17.7.1.2.2';
-	my $OID_1qPort = "$OID_1qTpFdbTable.1.2";
-	my $OID_1qStatus = "$OID_1qTpFdbTable.1.3";
 	my $vlan_fdb_table = my_get_table({
-		'port' => $OID_1qPort,
-		'status' => $OID_1qStatus,
+		'port' => "$OID_1qTpFdbTable.1.2",
+		'status' => "$OID_1qTpFdbTable.1.3",
 	});
 	print Dumper($vlan_fdb_table) if $debug;
 
-	for my $m (keys %$vlan_fdb_table) {
-		my $fdb = $vlan_fdb_table->{$m};
-		$fdb->{status} == 3 or next;	# Only learned MACs
-		my $port = $if_table->{$fdb->{port}} or die "Forwarding DB refers to unknown iface";
-		my @m = split /\./, $m;
-		my $vlan = shift @m;
-		my $mac = join(':', map { sprintf('%02x', $_) } @m);
-		push @{$port->{macs}}, $mac;
+	if (%$vlan_fdb_table) {
+		for my $m (keys %$vlan_fdb_table) {
+			my $fdb = $vlan_fdb_table->{$m};
+			$fdb->{status} == 3 or next;	# Only learned MACs
+			my $port = $if_table->{$fdb->{port}} or die "Forwarding DB refers to unknown iface";
+			my @m = split /\./, $m;
+			my $vlan = shift @m;
+			my $mac = join(':', map { sprintf('%02x', $_) } @m);
+			push @{$port->{macs}}, $mac;
+		}
+	} else {
+		print "# Trying fall-fack to .1d FDB\n" if $debug;
+		my $OID_1dTpFdbTable = '1.3.6.1.2.1.17.4.3';
+		my $fdb_table = my_get_table({
+			'port' => "$OID_1dTpFdbTable.1.2",
+			'status' => "$OID_1dTpFdbTable.1.3",
+		});
+		print Dumper($fdb_table) if $debug;
+		for my $m (keys %$fdb_table) {
+			my $fdb = $fdb_table->{$m};
+			$fdb->{status} == 3 or next;	# Only learned MACs
+			my $port = $if_table->{$fdb->{port}} or die "Forwarding DB refers to unknown iface";
+			my @m = split /\./, $m;
+			my $mac = join(':', map { sprintf('%02x', $_) } @m);
+			push @{$port->{macs}}, $mac;
+		}
 	}
+
 	for my $if (values %$if_table) {
 		$if->{macs} or next;
 		$if->{macs} = [ sort(List::Util::uniq(@{$if->{macs}})) ];
-- 
2.39.5