From cbc265bd2f77a5906fbca0460c127f68922ff032 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Sat, 18 Jun 2016 13:34:54 +0200
Subject: [PATCH] mxvlan: inital import

---
 mxvlan/mxvlanctl | 175 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)
 create mode 100755 mxvlan/mxvlanctl

diff --git a/mxvlan/mxvlanctl b/mxvlan/mxvlanctl
new file mode 100755
index 0000000..0509ee7
--- /dev/null
+++ b/mxvlan/mxvlanctl
@@ -0,0 +1,175 @@
+#! /usr/bin/perl
+use strict;
+use warnings;
+
+sub USAGE { "usage: $0 start|stop|restart\n" }
+
+my $hostname=`/bin/hostname`;chomp($hostname);
+$hostname=~s/\.molgen\.mpg\.de$//i;
+
+sub sys {
+	my ($cmd)=@_;
+	print "$cmd\n";
+	system $cmd and exit 1;
+}
+
+
+sub fix_eth {		# fix 'ethX' to 'netXX' if ethX does not exist, but netXX does (old name used in config)
+	my ($dev)=@_;
+	if ($dev=~/^eth(\d+)/ and !-d "/sys/class/net/$dev") {
+		my $netdev=sprintf('net%02d',$1);
+		-d  "/sys/class/net/$netdev" and return $netdev;
+	}
+	return $dev;
+}
+
+sub slurpfile {
+	my ($path)=@_;
+	open my $fh,'<',$path or die "$path: $!\n";
+	return join ('',<$fh>);
+}
+
+sub slurpfile_chomp {
+	my $data=slurpfile($_[0]);
+	chomp($data);
+	return $data;
+}
+
+
+
+sub get_netif_flags { my ($dev)=@_;return hex(slurpfile_chomp("/sys/class/net/$dev/flags"));}   	# see include/uapi/linux/if.h for meaning
+sub netif_is_up {my ($dev)=@_;return get_netif_flags($dev)&1;}
+
+
+sub read_active_vlans {
+	my $have_vlan={};	# { "eth5.150"=>1, ... }
+	my $have_addr={};	# { "141.14.12.12/24" => "eth5.150", .. }
+
+
+	my $file="/proc/net/vlan/config";
+	open IN,'<',$file or die "$file: $!\n";
+	while (<IN>) {
+		/^(\S+)\s*\|\s*(\d+)\s*\|\s*(\S+)\s*$/ or next;		# eth0.150       | 150  | eth0
+		my ($vlan_device,$vlan_num,$base_device)=($1,$2,$3);
+		$have_vlan->{$vlan_device}=[$base_device,$vlan_num];
+	}
+	open IN,'-|','ip','addr' or die "$!\n";
+	while (<IN>) {
+		if (my ($addr,$dev)=/^\s*inet (\S+) scope global (\S+)/) {
+			exists ($have_vlan->{$dev}) and $have_addr->{$addr}=$dev;
+		}
+	}
+	close IN;
+	return ($have_vlan,$have_addr);
+
+}
+
+sub read_mxvlans {
+	my $want_vlan={};	# { "eth5.150"=>[eth5,150]", "vlan.github"=>[net02,54], ... }
+	my $want_addr={};	# { "141.14.12.12/24" => "vlan.github", .. }
+
+	my $file='/etc/mxvlans';
+	open IN,'<',$file or die "$file: $!\n";
+	while (<IN>) {
+		s/#.*//;
+		chomp;
+		my @words=split;
+		@words or next;
+		eval {
+			@words==4 or @words==5 or die "format error : $_\n";
+			my ($host,$base_device,$vlan_num,$vlan_device,$cidr)=@words;
+			$base_device=fix_eth($base_device);	# temp accept ethX for netXX
+			if ($host eq $hostname) {
+				$vlan_num=~/^\d+$/ or die "VLAN number not numeric\n";
+				$want_vlan->{$vlan_device}=[$base_device,$vlan_num];
+				if (defined $cidr) {
+					$want_addr->{$cidr}=$vlan_device;
+				}
+			}			
+		};
+		if ($@) {
+			die "$file line $. : $@";
+		}
+	}
+	return ($want_vlan,$want_addr);
+}
+
+
+sub configure_vlans {
+	my ($want_vlan,$want_addr)=@_;
+	for my $device (sort keys %$want_vlan) {
+		my ($base_device,$vlan_num)=@{$want_vlan->{$device}};
+		sys("ip link set dev $base_device up") unless netif_is_up($base_device);
+		sys("ip link add link $base_device name $device type vlan id $vlan_num");
+	}
+	for my $ip (sort keys %$want_addr) {
+		my $device=$want_addr->{$ip};
+		sys("ip addr add $ip dev $device");
+	}
+	for my $device (sort keys %$want_vlan) {
+		sys("ip link set dev $device up");
+	}
+}
+
+sub unconfigure_vlans {
+	my ($have_vlan,$have_addr)=@_;
+
+	for my $device (sort keys %$have_vlan) {
+		sys("ip link set dev $device down");
+	}
+	for my $ip (sort keys %$have_addr) {
+		my $device=$have_addr->{$ip};
+		sys("ip addr delete $ip dev $device");
+	}
+	for my $device (sort keys %$have_vlan) {
+		my ($base_device,$vlan_num)=$device=~/^([^.]+)\.(.+)$/;
+		sys("ip link delete $device");
+	}
+}
+
+@ARGV==1 or die USAGE;
+
+my ($cmd)=@ARGV;
+
+
+if ($cmd eq 'start' or $cmd eq 'restart') {
+
+	-e "/proc/net/vlan/config" or sys("modprobe 8021q || true");
+
+	my ($want_vlan,$want_addr)=read_mxvlans();
+	my ($have_vlan,$have_addr)=read_active_vlans();
+	
+	my ($new_vlan,$new_addr,$del_vlan,$del_addr)=({},{},{},{});
+
+	for (keys %$want_vlan) {
+		$new_vlan->{$_}=$want_vlan->{$_}
+			unless exists $have_vlan->{$_}
+			&& $have_vlan->{$_}[0] eq $want_vlan->{$_}[0]
+			&& $have_vlan->{$_}[1] eq $want_vlan->{$_}[1];
+	}
+	for (keys %$want_addr) {
+		$new_addr->{$_}=$want_addr->{$_}
+			unless exists $have_addr->{$_}
+			&& $have_addr->{$_} eq $want_addr->{$_};
+	}
+	for (keys %$have_vlan) {
+		$del_vlan->{$_}=$have_vlan->{$_}
+			unless exists $want_vlan->{$_}
+			&& $have_vlan->{$_}[0] eq $want_vlan->{$_}[0]
+			&& $have_vlan->{$_}[1] eq $want_vlan->{$_}[1];
+	}
+	for (keys %$have_addr) {
+		$del_addr->{$_}=$have_addr->{$_}
+			unless exists $want_addr->{$_}
+			&& $want_addr->{$_} eq $have_addr->{$_};
+	}
+	unconfigure_vlans($del_vlan,$del_addr);
+	configure_vlans($new_vlan,$new_addr);
+} elsif ($cmd eq 'stop') {
+	my ($have_vlan,$have_addr)=read_active_vlans();
+	unconfigure_vlans($have_vlan,$have_addr);
+} else {
+	die USAGE;
+}
+
+