package PVE::INotify;

# todo: maybe we do not need update_file() ?
use strict;
use warnings;

use Clone qw(clone);
use Digest::SHA;
use Encode qw(encode decode);
use Fcntl qw(:DEFAULT :flock);
use File::Basename;
use File::stat;
use IO::Dir;
use IO::File;
use JSON;
use Linux::Inotify2;
use POSIX;

use PVE::Exception qw(raise_param_exc);
use PVE::JSONSchema;
use PVE::Network;
use PVE::ProcFSTools;
use PVE::SafeSyslog;
use PVE::Tools;

use base 'Exporter';

our @EXPORT_OK = qw(read_file write_file register_file nodename);

my $ccache;
my $ccachemap;
my $ccacheregex;
my $inotify;
my $inotify_pid = 0;
my $versions;
my $shadowfiles = {
    '/etc/network/interfaces' => '/etc/network/interfaces.new',
};

# to enable cached operation, you need to call 'inotify_init'
# inotify handles are a limited resource, so use with care (only
# enable the cache if you really need it)

# Note: please close the inotify handle after you fork

sub ccache_default_writer {
    my ($filename, $data) = @_;

    die "undefined config writer for '$filename' :ERROR";
}

sub ccache_default_parser {
    my ($filename, $srcfd) = @_;

    die "undefined config reader for '$filename' :ERROR";
}

sub ccache_compute_diff {
    my ($filename, $shadow) = @_;

    my $diff = '';

    my $cmd = ['/usr/bin/diff', '-b', '-N', '-u', $filename, $shadow];
    PVE::Tools::run_command(
        $cmd,
        noerr => 1,
        outfunc => sub {
            my ($line) = @_;
            $diff .= decode('UTF-8', $line) . "\n";
        },
    );

    $diff = undef if !$diff;

    return $diff;
}

sub ccache_info {
    my ($filename) = @_;

    foreach my $uid (keys %$ccacheregex) {
        my $ccinfo = $ccacheregex->{$uid};
        my $dir = $ccinfo->{dir};
        my $regex = $ccinfo->{regex};
        if ($filename =~ m|^$dir/+$regex$|) {
            if (!$ccache->{$filename}) {
                my $cp = {};
                while (my ($k, $v) = each %$ccinfo) {
                    $cp->{$k} = $v;
                }
                $ccache->{$filename} = $cp;
            }
            return ($ccache->{$filename}, $filename);
        }
    }

    $filename = $ccachemap->{$filename} if defined($ccachemap->{$filename});

    die "file '$filename' not added :ERROR" if !defined($ccache->{$filename});

    return ($ccache->{$filename}, $filename);
}

sub write_file {
    my ($fileid, $data, $full) = @_;

    my ($ccinfo, $filename) = ccache_info($fileid);

    my $writer = $ccinfo->{writer};

    my $realname = $filename;

    my $shadow;
    if ($shadow = $shadowfiles->{$filename}) {
        $realname = $shadow;
    }

    my $perm = $ccinfo->{perm} || 0644;

    my $tmpname = "$realname.tmp.$$";

    my $res;
    eval {
        my $fh = IO::File->new($tmpname, O_WRONLY | O_CREAT, $perm);
        die "unable to open file '$tmpname' - $!\n" if !$fh;

        $res = &$writer($filename, $fh, $data);

        die "closing file '$tmpname' failed - $!\n" unless close $fh;
    };
    my $err = $@;

    $ccinfo->{version} = undef;

    if ($err) {
        unlink $tmpname;
        die $err;
    }

    if (!rename($tmpname, $realname)) {
        my $msg = "close (rename) atomic file '$filename' failed: $!\n";
        unlink $tmpname;
        die $msg;
    }

    my $diff;
    if ($shadow && $full) {
        $diff = ccache_compute_diff($filename, $shadow);
    }

    if ($full) {
        return { data => $res, changes => $diff };
    }

    return $res;
}

sub update_file {
    my ($fileid, $data, @args) = @_;

    my ($ccinfo, $filename) = ccache_info($fileid);

    my $update = $ccinfo->{update};

    die "unable to update/merge data" if !$update;

    my $lkfn = "$filename.lock";

    my $timeout = 10;

    my $fd;

    my $code = sub {

        $fd = IO::File->new($filename, "r");

        my $new = &$update($filename, $fd, $data, @args);

        if (defined($new)) {
            PVE::Tools::file_set_contents($filename, $new, $ccinfo->{perm});
        } else {
            unlink $filename;
        }
    };

    PVE::Tools::lock_file($lkfn, $timeout, $code);
    my $err = $@;

    close($fd) if defined($fd);

    die $err if $err;

    return undef;
}

sub discard_changes {
    my ($fileid, $full) = @_;

    my ($ccinfo, $filename) = ccache_info($fileid);

    if (my $copy = $shadowfiles->{$filename}) {
        unlink $copy;
    }

    return read_file($filename, $full);
}

sub poll_changes {
    my ($filename) = @_;

    poll() if $inotify; # read new inotify events

    $versions->{$filename} = 0 if !defined($versions->{$filename});

    return $versions->{$filename};
}

sub read_file {
    my ($fileid, $full) = @_;

    my $parser;

    my ($ccinfo, $filename) = ccache_info($fileid);

    $parser = $ccinfo->{parser};

    my $fd;
    my $shadow;

    my $cver = poll_changes($filename);

    if (my $copy = $shadowfiles->{$filename}) {
        if ($fd = IO::File->new($copy, "r")) {
            $shadow = $copy;
        } else {
            $fd = IO::File->new($filename, "r");
        }
    } else {
        $fd = IO::File->new($filename, "r");
    }

    my $acp = $ccinfo->{always_call_parser};

    if (!$fd) {
        $ccinfo->{version} = undef;
        $ccinfo->{data} = undef;
        $ccinfo->{diff} = undef;
        return undef if !$acp;
    }

    my $noclone = $ccinfo->{noclone};

    # file unchanged?
    if (
        !$ccinfo->{nocache}
        && $inotify
        && $cver
        && defined($ccinfo->{data})
        && defined($ccinfo->{version})
        && ($ccinfo->{readonce}
            || ($ccinfo->{version} == $cver))
    ) {

        my $ret;
        if (!$noclone && ref($ccinfo->{data})) {
            $ret->{data} = clone($ccinfo->{data});
        } else {
            $ret->{data} = $ccinfo->{data};
        }
        $ret->{changes} = $ccinfo->{diff};

        return $full ? $ret : $ret->{data};
    }

    my $diff;

    if ($shadow) {
        $diff = ccache_compute_diff($filename, $shadow);
    }

    my $res = &$parser($filename, $fd);

    if (!$ccinfo->{nocache}) {
        $ccinfo->{version} = $cver;
    }

    # we cache data with references, so we always need to
    # clone this data. Else the original data may get
    # modified.
    $ccinfo->{data} = $res;

    # also store diff
    $ccinfo->{diff} = $diff;

    my $ret;
    if (!$noclone && ref($ccinfo->{data})) {
        $ret->{data} = clone($ccinfo->{data});
    } else {
        $ret->{data} = $ccinfo->{data};
    }
    $ret->{changes} = $ccinfo->{diff};

    return $full ? $ret : $ret->{data};
}

sub parse_ccache_options {
    my ($ccinfo, %options) = @_;

    foreach my $opt (keys %options) {
        my $v = $options{$opt};
        if ($opt eq 'readonce') {
            $ccinfo->{$opt} = $v;
        } elsif ($opt eq 'nocache') {
            $ccinfo->{$opt} = $v;
        } elsif ($opt eq 'shadow') {
            $ccinfo->{$opt} = $v;
        } elsif ($opt eq 'perm') {
            $ccinfo->{$opt} = $v;
        } elsif ($opt eq 'noclone') {
            # noclone flag for large read-only data chunks like aplinfo
            $ccinfo->{$opt} = $v;
        } elsif ($opt eq 'always_call_parser') {
            # when set, we call parser even when the file does not exist.
            # this allows the parser to return some default
            $ccinfo->{$opt} = $v;
        } else {
            die "internal error - unsupported option '$opt'";
        }
    }
}

sub register_file {
    my ($id, $filename, $parser, $writer, $update, %options) = @_;

    die "can't register file '$filename' after inotify_init" if $inotify;

    die "file '$filename' already added :ERROR" if defined($ccache->{$filename});
    die "ID '$id' already used :ERROR" if defined($ccachemap->{$id});

    my $ccinfo = {};

    $ccinfo->{id} = $id;
    $ccinfo->{parser} = $parser || \&ccache_default_parser;
    $ccinfo->{writer} = $writer || \&ccache_default_writer;
    $ccinfo->{update} = $update;

    parse_ccache_options($ccinfo, %options);

    if ($options{shadow}) {
        $shadowfiles->{$filename} = $options{shadow};
    }

    $ccachemap->{$id} = $filename;
    $ccache->{$filename} = $ccinfo;
}

sub register_regex {
    my ($dir, $regex, $parser, $writer, $update, %options) = @_;

    die "can't register regex after inotify_init" if $inotify;

    my $uid = "$dir/$regex";
    die "regular expression '$uid' already added :ERROR" if defined($ccacheregex->{$uid});

    my $ccinfo = {};

    $ccinfo->{dir} = $dir;
    $ccinfo->{regex} = $regex;
    $ccinfo->{parser} = $parser || \&ccache_default_parser;
    $ccinfo->{writer} = $writer || \&ccache_default_writer;
    $ccinfo->{update} = $update;

    parse_ccache_options($ccinfo, %options);

    $ccacheregex->{$uid} = $ccinfo;
}

sub poll {
    return if !$inotify;

    if ($inotify_pid != $$) {
        syslog('err', "got inotify poll request in wrong process - disabling inotify");
        $inotify = undef;
    } else {
        1 while $inotify && $inotify->poll;
    }
}

sub flushcache {
    foreach my $filename (keys %$ccache) {
        $ccache->{$filename}->{version} = undef;
        $ccache->{$filename}->{data} = undef;
        $ccache->{$filename}->{diff} = undef;
    }
}

sub inotify_close {
    $inotify = undef;
}

sub inotify_init {

    die "only one inotify instance allowed" if $inotify;

    $inotify = Linux::Inotify2->new()
        || die "Unable to create new inotify object: $!";

    $inotify->blocking(0);

    $versions = {};

    my $dirhash = {};
    foreach my $fn (keys %$ccache) {
        my $dir = dirname($fn);
        my $base = basename($fn);

        $dirhash->{$dir}->{$base} = $fn;

        if (my $sf = $shadowfiles->{$fn}) {
            $base = basename($sf);
            $dir = dirname($sf);
            $dirhash->{$dir}->{$base} = $fn; # change version of original file!
        }
    }

    foreach my $uid (keys %$ccacheregex) {
        my $ccinfo = $ccacheregex->{$uid};
        $dirhash->{ $ccinfo->{dir} }->{_regex} = 1;
    }

    $inotify_pid = $$;

    foreach my $dir (keys %$dirhash) {

        my $evlist = IN_MODIFY | IN_ATTRIB | IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE;
        $inotify->watch(
            $dir,
            $evlist,
            sub {
                my $e = shift;
                my $name = $e->name;

                if ($inotify_pid != $$) {
                    syslog('err', "got inotify event in wrong process");
                }

                if ($e->IN_ISDIR || !$name) {
                    return;
                }

                if ($e->IN_Q_OVERFLOW) {
                    syslog('info', "got inotify overflow - flushing cache");
                    flushcache();
                    return;
                }

                if ($e->IN_UNMOUNT) {
                    syslog('err', "got 'unmount' event on '$name' - disabling inotify");
                    $inotify = undef;
                }
                if ($e->IN_IGNORED) {
                    syslog('err', "got 'ignored' event on '$name' - disabling inotify");
                    $inotify = undef;
                }

                if ($dirhash->{$dir}->{_regex}) {
                    foreach my $uid (keys %$ccacheregex) {
                        my $ccinfo = $ccacheregex->{$uid};
                        next if $dir ne $ccinfo->{dir};
                        my $regex = $ccinfo->{regex};
                        if ($regex && ($name =~ m|^$regex$|)) {

                            my $fn = "$dir/$name";
                            $versions->{$fn}++;
                            #print "VERSION:$fn:$versions->{$fn}\n";
                        }
                    }
                } elsif (my $fn = $dirhash->{$dir}->{$name}) {

                    $versions->{$fn}++;
                    #print "VERSION:$fn:$versions->{$fn}\n";
                }
            },
        );
    }

    foreach my $dir (keys %$dirhash) {
        foreach my $name (keys %{ $dirhash->{$dir} }) {
            if ($name eq '_regex') {
                foreach my $uid (keys %$ccacheregex) {
                    my $ccinfo = $ccacheregex->{$uid};
                    next if $dir ne $ccinfo->{dir};
                    my $re = $ccinfo->{regex};
                    if (my $fd = IO::Dir->new($dir)) {
                        while (defined(my $de = $fd->read)) {
                            if ($de =~ m/^$re$/) {
                                my $fn = "$dir/$de";
                                $versions->{$fn}++; # init with version
                                #print "init:$fn:$versions->{$fn}\n";
                            }
                        }
                    }
                }
            } else {
                my $fn = $dirhash->{$dir}->{$name};
                $versions->{$fn}++; # init with version
                #print "init:$fn:$versions->{$fn}\n";
            }
        }
    }
}

my $cached_nodename;

sub nodename {
    return $cached_nodename if $cached_nodename;

    my ($sysname, $nodename) = POSIX::uname();
    $nodename =~ s/\..*$//; # strip domain part, if any

    die "unable to read node name\n" if !$nodename;

    $cached_nodename = $nodename;

    return $cached_nodename;
}

sub read_etc_hostname {
    my ($filename, $fd) = @_;

    my $hostname = <$fd>;

    chomp $hostname;

    $hostname =~ s/\..*$//; # strip domain part, if any

    return $hostname;
}

sub write_etc_hostname {
    my ($filename, $fh, $hostname) = @_;

    die "write failed: $!" unless print $fh "$hostname\n";

    return $hostname;
}

register_file('hostname', "/etc/hostname", \&read_etc_hostname, \&write_etc_hostname);

sub read_etc_hosts {
    my ($filename, $fh) = @_;

    my $raw = '';
    my $data = '';

    while (my $line = <$fh>) {
        $raw .= $line;
        if ($line =~ m/^\s*#/) {
            $line = decode('UTF-8', $line);
        }
        $data .= $line;
    }

    return {
        digest => Digest::SHA::sha1_hex($raw),
        data => $data,
    };
}

sub write_etc_hosts {
    my ($filename, $fh, $hosts, @args) = @_;

    # check validity of ips/names
    for my $line (split("\n", $hosts)) {
        next if $line =~ m/^\s*#/; # comments
        next if $line =~ m/^\s*$/; # whitespace/empty lines

        my ($ip, @names) = split(/\s+/, $line);

        raise_param_exc({ 'data' => "Invalid IP '$ip'" })
            if $ip !~ m/^$PVE::Tools::IPRE$/;

        for my $name (@names) {
            raise_param_exc({ 'data' => "Invalid Hostname '$name'" })
                if $name !~ m/^[.\-a-zA-Z0-9]+$/;
        }
    }

    die "write failed: $!" if !print $fh encode('UTF-8', $hosts);

    return $hosts;
}

register_file('etchosts', "/etc/hosts", \&read_etc_hosts, \&write_etc_hosts);

sub read_etc_resolv_conf {
    my ($filename, $fh) = @_;

    my $res = {};

    my $nscount = 0;
    while (my $line = <$fh>) {
        chomp $line;
        if ($line =~ m/^(search|domain)\s+(\S+)\s*/) {
            $res->{search} = $2;
        } elsif ($line =~ m/^\s*nameserver\s+($PVE::Tools::IPRE)\s*/) {
            $nscount++;
            if ($nscount <= 3) {
                $res->{"dns$nscount"} = $1;
            }
        }
    }

    return $res;
}

sub update_etc_resolv_conf {
    my ($filename, $fh, $resolv, @args) = @_;

    my $data = "";

    $data = "search $resolv->{search}\n"
        if $resolv->{search};

    my $written = {};
    foreach my $k ("dns1", "dns2", "dns3") {
        my $ns = $resolv->{$k};
        if ($ns && $ns ne '0.0.0.0' && !$written->{$ns}) {
            $written->{$ns} = 1;
            $data .= "nameserver $ns\n";
        }
    }

    while (my $line = <$fh>) {
        next if $line =~ m/^(search|domain|nameserver)\s+/;
        $data .= $line;
    }

    return $data;
}

register_file(
    'resolvconf',
    "/etc/resolv.conf",
    \&read_etc_resolv_conf,
    undef,
    \&update_etc_resolv_conf,
);

sub read_etc_timezone {
    my ($filename, $fd) = @_;

    my $timezone = <$fd>;

    chomp $timezone;

    return $timezone;
}

sub write_etc_timezone {
    my ($filename, $fh, $timezone) = @_;

    my $tzinfo = "/usr/share/zoneinfo/$timezone";

    raise_param_exc({ 'timezone' => "No such timezone" })
        if (!-f $tzinfo);

    ($timezone) = $timezone =~ m/^(.*)$/; # untaint

    print $fh "$timezone\n";

    unlink("/etc/localtime");
    symlink("/usr/share/zoneinfo/$timezone", "/etc/localtime");

}

register_file('timezone', "/etc/timezone", \&read_etc_timezone, \&write_etc_timezone);

sub read_active_workers {
    my ($filename, $fh) = @_;

    return [] if !$fh;

    my $res = [];
    while (defined(my $line = <$fh>)) {
        if ($line =~ m/^(\S+)\s(0|1)(\s([0-9A-Za-z]{8})(\s(\s*\S.*))?)?$/) {
            my $upid = $1;
            my $saved = $2;
            my $endtime = $4;
            my $status = $6;
            if ((my $task = PVE::Tools::upid_decode($upid, 1))) {
                $task->{upid} = $upid;
                $task->{saved} = $saved;
                $task->{endtime} = hex($endtime) if $endtime;
                $task->{status} = $status if $status;
                push @$res, $task;
            }
        } else {
            warn "unable to parse line: $line";
        }
    }

    return $res;

}

sub write_active_workers {
    my ($filename, $fh, $tasklist) = @_;

    my $raw = '';
    foreach my $task (@$tasklist) {
        my $upid = $task->{upid};
        my $saved = $task->{saved} ? 1 : 0;
        if ($task->{endtime}) {
            if ($task->{status}) {
                $raw .=
                    sprintf("%s %s %08X %s\n", $upid, $saved, $task->{endtime}, $task->{status});
            } else {
                $raw .= sprintf("%s %s %08X\n", $upid, $saved, $task->{endtime});
            }
        } else {
            $raw .= "$upid $saved\n";
        }
    }

    PVE::Tools::safe_print($filename, $fh, $raw) if $raw;
}

register_file('active', "/var/log/pve/tasks/active", \&read_active_workers, \&write_active_workers);

our $bond_modes = {
    'balance-rr' => 0,
    'active-backup' => 1,
    'balance-xor' => 2,
    'broadcast' => 3,
    '802.3ad' => 4,
    'balance-tlb' => 5,
    'balance-alb' => 6,
};

my $ovs_bond_modes = {
    'active-backup' => 1,
    'balance-slb' => 1,
    'lacp-balance-slb' => 1,
    'lacp-balance-tcp' => 1,
};

#sub get_bond_modes {
#    return $bond_modes;
#}

my $parse_ovs_option = sub {
    my ($data) = @_;

    my $opts = {};
    foreach my $kv (split(/\s+/, $data || '')) {
        my ($k, $v) = split('=', $kv, 2);
        $opts->{$k} = $v if $k && defined($v);
    }
    return $opts;
};

my $set_ovs_option = sub {
    my ($d, %params) = @_;

    my $opts = &$parse_ovs_option($d->{ovs_options});

    foreach my $k (keys %params) {
        my $v = $params{$k};
        if ($v) {
            $opts->{$k} = $v;
        } else {
            delete $opts->{$k};
        }
    }

    my $res = [];
    foreach my $k (keys %$opts) {
        push @$res, "$k=$opts->{$k}";
    }

    if (my $new = join(' ', @$res)) {
        $d->{ovs_options} = $new;
        return $d->{ovs_options};
    } else {
        delete $d->{ovs_options};
        return undef;
    }
};

my $extract_ovs_option = sub {
    my ($d, $name) = @_;

    my $opts = &$parse_ovs_option($d->{ovs_options});

    my $v = delete $opts->{$name};

    my $res = [];
    foreach my $k (keys %$opts) {
        push @$res, "$k=$opts->{$k}";
    }

    if (my $new = join(' ', @$res)) {
        $d->{ovs_options} = $new;
    } else {
        delete $d->{ovs_options};
    }

    return $v;
};

my $check_mtu = sub {
    my ($ifaces, $parent, $child) = @_;

    die "check mtu - missing parent interface\n" if !$parent;
    die "check mtu - missing child interface\n" if !$child;

    my $cmtu = $ifaces->{$child}->{mtu};
    return if !$cmtu;

    my $parentdata = $ifaces->{$parent};
    my $pmtu = $parentdata->{mtu};
    $pmtu = $cmtu if $parentdata->{type} eq 'bond' && !$pmtu;
    $pmtu = 1500 if !$pmtu;

    die "interface '$parent' - mtu $pmtu is lower than '$child' - mtu $cmtu\n"
        if $pmtu < $cmtu;
};

# config => {
#   ifaces => {
#     $ifname => {
#       <optional> exists => BOOL,
#       <optional> active => BOOL,
#       <optional> autostart => BOOL,
#       <auto> priority => INT,
#
#       type => "eth" | "bridge" | "bond" | "loopback" | "OVS*" | ... ,
#
#       families => ["inet", "inet6", ...],
#
#       method => "manual" | "static" | "dhcp" | ... ,
#       address => IP,
#       netmask => SUBNET,
#       broadcast => IP,
#       gateway => IP,
#       comments => [ "..." ],
#
#       method6 => "manual" | "static" | "dhcp" | ... ,
#       address6 => IP,
#       netmask6 => SUBNET,
#       gateway6 => IP,
#       comments6 => [ "..." ],
#
#       <known options>, # like bridge_ports, ovs_*
#
#       # extra/unknown options stored by-family:
#       options => { <inet options>... }
#       options6 => { <inet6 options>... }
#     }
#   },
#   options => [
#     # mappings end up here as well, as we don't need to understand them
#     [priority,line]
#   ]
# }
sub read_etc_network_interfaces {
    my ($filename, $fh) = @_;
    my $ip_links = PVE::Network::ip_link_details();
    my $active = PVE::ProcFSTools::get_active_network_interfaces();
    return __read_etc_network_interfaces($fh, $ip_links, $active);
}

sub __read_etc_network_interfaces {
    my ($fh, $ip_links, $active_ifaces) = @_;

    my $config = {};
    my $ifaces = $config->{ifaces} = {};
    my $options = $config->{options} = [];

    my $altnames = PVE::Network::altname_mapping($ip_links);

    my $options_alternatives = {
        'ovs_mtu' => 'mtu',
        'bond-slaves' => 'slaves',
        'bond_slaves' => 'slaves',
        'bond-xmit-hash-policy' => 'bond_xmit_hash_policy',
        'bond-mode' => 'bond_mode',
        'bond-miimon' => 'bond_miimon',
        'bridge-vlan-aware' => 'bridge_vlan_aware',
        'bridge-fd' => 'bridge_fd',
        'bridge-stp' => 'bridge_stp',
        'bridge-ports' => 'bridge_ports',
        'bridge-vids' => 'bridge_vids',
    };

    my $line;

    # we try to keep order inside the file
    my $priority = 2; # 1 is reserved for lo

SECTION: while (defined($line = <$fh>)) {
        chomp($line);
        next if $line =~ m/^\s*#/;

        if ($line =~ m/^\s*(allow-auto|auto|allow-ovs)\s+(.*)$/) {

            $ifaces->{$_}->{autostart} = 1 for split(/\s+/, $2);

        } elsif ($line =~ m/^\s*(allow-hotplug)\s+(.*)$/) {

            # FIXME: handle those differently? auto makes it required on-boot, vs. best-effort
            $ifaces->{$_}->{autostart} = 1 for split(/\s+/, $2);

        } elsif ($line =~ m/^\s*iface\s+(\S+)(?:\s+(inet6?)\s+(\S+))?\s*$/) {
            my $i = $1;
            my $family = $2;
            my $f = { method => $3 }; # by family, merged to $d with a $suffix
            my $suffix = $family;
            $suffix =~ s/^inet// if defined $suffix;

            my $d = $ifaces->{$i} ||= {};
            $d->{priority} = $priority++ if !$d->{priority};

            # $family may be undef, an undef family means we have a stanza
            # without an `inet` or `inet6` section
            push @{ $d->{families} }, $family;

            while (defined($line = <$fh>)) {
                $line =~ s/\s+$//; # drop trailing whitespaces

                if ($line =~ m/^\s*#(.*?)\s*$/) {
                    my $pushto = defined($suffix) ? $f : $d;
                    $pushto->{comments} = '' if !$pushto->{comments};
                    my $comment = decode('UTF-8', $1);
                    $pushto->{comments} .= "$comment\n";
                } elsif ($line =~ m/^\s*(?:(?:iface|mapping|auto|source|source-directory)\s|allow-)/
                ) {
                    last;
                } elsif ($line =~ m/^\s*((\S+)\s+(.+))$/) {
                    my $option = $1;
                    my ($id, $value) = ($2, $3);

                    $id = $options_alternatives->{$id} if $options_alternatives->{$id};

                    my $simple_options = {
                        'mtu' => 1,
                        'ovs_type' => 1,
                        'ovs_options' => 1,
                        'ovs_bridge' => 1,
                        'ovs_bonds' => 1,
                        'ovs_ports' => 1,
                        'bridge_fd' => 1,
                        'bridge_vids' => 1,
                        'bridge-access' => 1,
                        'bridge-learning' => 1,
                        'bridge-arp-nd-suppress' => 1,
                        'bridge-unicast-flood' => 1,
                        'bridge-multicast-flood' => 1,
                        'bridge-disable-mac-learning' => 1,
                        'bond_miimon' => 1,
                        'bond_xmit_hash_policy' => 1,
                        'bond-primary' => 1,
                        'link-type' => 1,
                        'uplink-id' => 1,
                        'vlan-protocol' => 1,
                        'vlan-raw-device' => 1,
                        'vlan-id' => 1,
                        'vxlan-id' => 1,
                        'vxlan-svcnodeip' => 1,
                        'vxlan-physdev' => 1,
                        'vxlan-local-tunnelip' => 1,
                    };

                    if (
                        $id eq 'address'
                        || $id eq 'netmask'
                        || $id eq 'broadcast'
                        || $id eq 'gateway'
                    ) {
                        if (defined($suffix)) {
                            $d->{ $id . $suffix } = $value;
                        } elsif ($id ne 'netmask') {
                            if ($value =~ /:/) {
                                $d->{ $id . '6' } = $value;
                            } else {
                                $d->{$id} = $value;
                            }
                        } else {
                            $d->{$id} = $value;
                        }
                    } elsif ($simple_options->{$id}) {
                        $d->{$id} = $value;
                    } elsif ($id eq 'slaves' || $id eq 'bridge_ports') {
                        my $devs = {};
                        foreach my $p (split(/\s+/, $value)) {
                            next if $p eq 'none';
                            $devs->{$p} = 1;
                        }
                        my $str = join(' ', sort keys %{$devs});
                        if ($d->{$id}) {
                            $d->{$id} .= ' ' . $str if $str;
                        } else {
                            $d->{$id} = $str || '';
                        }
                    } elsif ($id eq 'bridge_stp') {
                        if ($value =~ m/^\s*(on|yes)\s*$/i) {
                            $d->{$id} = 'on';
                        } else {
                            $d->{$id} = 'off';
                        }
                    } elsif ($id eq 'bridge_vlan_aware') {
                        $d->{$id} = 1;
                    } elsif ($id eq 'bond_mode') {
                        # always use names
                        foreach my $bm (keys %$bond_modes) {
                            if ($bond_modes->{$bm} eq $value) {
                                $value = $bm;
                                last;
                            }
                        }
                        $d->{$id} = $value;
                    } elsif ($id eq 'vxlan-remoteip') {
                        push @{ $d->{$id} }, $value;
                    } else {
                        my $pushto = defined($suffix) ? $f : $d;
                        push @{ $pushto->{options} }, $option;
                    }
                } else {
                    last;
                }
            }
            if (defined($suffix)) {
                $d->{"$_$suffix"} = $f->{$_} for keys $f->%*;
            }
            last SECTION if !defined($line);
            redo SECTION;
        } elsif ($line =~ /\w/) {
            push @$options, [$priority++, $line];
        }
    }

OUTER:
    for my $iface_name (keys $ip_links->%*) {
        my $ip_link = $ip_links->{$iface_name};

        next if !PVE::Network::ip_link_is_physical($ip_link);

        for my $altname ($ip_link->{altnames}->@*) {
            if ($ifaces->{$altname}) {
                $ifaces->{$altname}->{exists} = 1;
                next OUTER;
            }
        }

        $ifaces->{$iface_name}->{exists} = 1;
    }

    foreach my $ifname (@$active_ifaces) {
        if (my $iface = $ifaces->{$ifname}) {
            $iface->{active} = 1;
        }
    }

    if (!$ifaces->{lo}) {
        $ifaces->{lo} = {
            priority => 1,
            method => 'loopback',
            type => 'loopback',
            autostart => 1,
        };
    }

    foreach my $iface (sort keys %$ifaces) {
        my $d = $ifaces->{$iface};
        $d->{type} = 'unknown';

        my $ip_link = $ip_links->{$altnames->{$iface} // $iface};

        if (defined $d->{'bridge_ports'}) {
            $d->{type} = 'bridge';
            if (!defined($d->{bridge_stp})) {
                $d->{bridge_stp} = 'off';
            }
            if (!defined($d->{bridge_fd}) && $d->{bridge_stp} eq 'off') {
                $d->{bridge_fd} = 0;
            }
        } elsif ($d->{ovs_type} && $d->{ovs_type} eq 'OVSBridge') {
            $d->{type} = $d->{ovs_type};
        } elsif ($iface =~ m/^bond\d+$/) {
            if (!$d->{ovs_type}) {
                $d->{type} = 'bond';
            } elsif ($d->{ovs_type} eq 'OVSBond') {
                $d->{type} = $d->{ovs_type};
                # translate: ovs_options => bond_mode
                $d->{'bond_mode'} = &$extract_ovs_option($d, 'bond_mode');
                my $lacp = &$extract_ovs_option($d, 'lacp');
                if ($lacp && $lacp eq 'active') {
                    if ($d->{'bond_mode'} eq 'balance-slb') {
                        $d->{'bond_mode'} = 'lacp-balance-slb';
                    }
                }
                # Note: balance-tcp needs lacp
                if ($d->{'bond_mode'} eq 'balance-tcp') {
                    $d->{'bond_mode'} = 'lacp-balance-tcp';
                }
                my $tag = &$extract_ovs_option($d, 'tag');
                $d->{ovs_tag} = $tag if defined($tag);
            }
        } elsif ($iface =~ m/^(\S+):\d+$/) {
            $d->{type} = 'alias';
            if (defined($ifaces->{$1})) {
                $d->{exists} = $ifaces->{$1}->{exists};
            } else {
                $ifaces->{$1}->{exists} = 0;
                $d->{exists} = 0;
            }
        } elsif ($iface =~ m/^(\S+)\.(\d+)$/) {
            $d->{type} = 'vlan';

            my ($dev, $id) = ($1, $2);
            $d->{'vlan-raw-device'} = $dev if defined($dev) && !$d->{'vlan-raw-device'};
            $d->{'vlan-id'} = $id if $id; # VLAN id 0 is not valid, so truthy check it is

            my $raw_iface = $d->{'vlan-raw-device'};

            if (defined($ifaces->{$raw_iface})) {
                $d->{exists} = $ifaces->{$raw_iface}->{exists};
            } else {
                $ifaces->{$raw_iface}->{exists} = 0;
                $d->{exists} = 0;
            }
        } elsif ($d->{'vlan-raw-device'}) {
            $d->{type} = 'vlan';

            if ($iface =~ m/^vlan(\d+)$/) {
                $d->{'vlan-id'} = $1 if $1; # VLAN id 0 is not valid, so truthy check it is
            }

            my $raw_iface = $d->{'vlan-raw-device'};

            if (defined($ifaces->{$raw_iface})) {
                $d->{exists} = $ifaces->{$raw_iface}->{exists};
            } else {
                $ifaces->{$raw_iface}->{exists} = 0;
                $d->{exists} = 0;
            }
        } elsif (($ip_link && PVE::Network::ip_link_is_physical($ip_link))
            || $iface =~ m/^$PVE::Network::PHYSICAL_NIC_RE$/) {
            if (!$d->{ovs_type}) {
                $d->{type} = 'eth';
            } elsif ($d->{ovs_type} eq 'OVSPort') {
                $d->{type} = $d->{ovs_type};
                my $tag = &$extract_ovs_option($d, 'tag');
                $d->{ovs_tag} = $tag if defined($tag);
            }
        } elsif ($iface =~ m/^lo$/) {
            $d->{type} = 'loopback';
        } else {
            if ($d->{'vxlan-id'}) {
                $d->{type} = 'vxlan';
            } elsif (defined($d->{ovs_type})) {
                if ($d->{ovs_type} eq 'OVSIntPort') {
                    $d->{type} = $d->{ovs_type};
                    my $tag = &$extract_ovs_option($d, 'tag');
                    $d->{ovs_tag} = $tag if defined($tag);
                }
            } elsif (defined($d->{'link-type'})) {
                $d->{type} = $d->{'link-type'} if $d->{'link-type'} eq 'dummy';
            }
        }

        # map address and netmask to cidr
        if (my $addr = $d->{address}) {
            if (_address_is_cidr($addr)) {
                $d->{cidr} = $addr;
                my ($baseaddr, $mask) = _cidr_split($addr);
                $d->{address} = $baseaddr;
                $d->{netmask} = $mask;
            } elsif (my $cidr = _get_cidr($d->{address}, $d->{netmask})) {
                $d->{cidr} = $cidr;
                (undef, $d->{netmask}) = _cidr_split($cidr);
            } else {
                # no mask, else we'd got a cidr above
                $d->{cidr} = $addr . "/32";
            }
        }

        # map address6 and netmask6 to cidr6
        if (my $addr6 = $d->{address6}) {
            if (_address_is_cidr($addr6)) {
                $d->{cidr6} = $addr6;
                my ($baseaddr, $mask) = _cidr_split($addr6);
                $d->{address6} = $baseaddr;
                $d->{netmask6} = $mask;
            } elsif (my $cidr6 = _get_cidr($d->{address6}, $d->{netmask6})) {
                $d->{cidr6} = $cidr6;
            } else {
                # no mask, else we'd got a cidr above
                $d->{cidr6} = $addr6 . "/128";
            }
        }

        $d->{method} = 'manual' if !$d->{method};
        $d->{method6} = 'manual' if !$d->{method6};

        if (my $comments6 = delete $d->{comments6}) {
            $d->{comments} = ($d->{comments} // '') . $comments6;
        }

        $d->{families} ||= ['inet'];
    }

    # OVS bridges create "allow-$BRIDGE $IFACE" lines which we need to remove
    # from the {options} hash for them to be removed correctly.
    @$options = grep { defined($_) } map {
        my ($pri, $line) = @$_;
        if ($line =~ /^allow-ovs\s+(.*)$/) {
            undef;
        } elsif ($line =~ /^allow-(\S+)\s+(.*)$/) {
            my $bridge = $1;
            my @ports = split(/\s+/, $2);
            if (defined(my $br = $ifaces->{$bridge})) {
                # if this port is part of a bridge, remove it
                my %in_ovs_ports = map { $_ => 1 } split(/\s+/, $br->{ovs_ports});
                @ports = grep { not $in_ovs_ports{$_} } @ports;
            }
            # create the allow line for the remaining ports, or delete if empty
            if (@ports) {
                [$pri, "allow-$bridge " . join(' ', @ports)];
            } else {
                undef;
            }
        } else {
            # don't modify other lines
            $_;
        }
    } @$options;

    return $config;
}

sub _address_is_cidr {
    my ($addr) = @_;
    return $addr =~ /\/\d+$/ ? 1 : 0;
}

sub _cidr_split {
    my ($cidr) = @_;
    $cidr =~ /^(.+)\/(\d+)$/;
    return ($1, $2); # (address, mask)
}

sub _get_cidr {
    my ($addr, $mask) = @_;

    return $addr if _address_is_cidr($addr);
    return undef if !$mask;

    if ($mask =~ m/^\d+$/) { # cidr notation
        return $addr . "/" . $mask;
    } elsif (my $cidrmask = PVE::JSONSchema::get_netmask_bits($mask)) {
        return $addr . "/" . $cidrmask;
    }
    return undef;
}

sub __interface_to_string {
    my ($iface, $d, $family, $first_block, $ifupdown2) = @_;

    my $suffix = $family;
    $suffix =~ s/^inet// if defined($suffix);

    return '' if $family && !($d && $d->{"method$suffix"});

    my $raw = "iface $iface";
    $raw .= " $family " . $d->{"method$suffix"} if defined $family;
    $raw .= "\n";

    my $add_addr = sub {
        my ($suffix) = @_;
        if (my $addr = $d->{"address$suffix"}) {
            if ($addr !~ /\/\d+$/ && $d->{"netmask$suffix"}) {
                if ($d->{"netmask$suffix"} =~ m/^\d+$/) {
                    $addr .= "/" . $d->{"netmask$suffix"};
                } elsif (my $mask = PVE::JSONSchema::get_netmask_bits($d->{"netmask$suffix"})) {
                    $addr .= "/" . $mask;
                }
            }
            $raw .= "\taddress ${addr}\n";
        }

        $raw .= "\tgateway " . $d->{"gateway$suffix"} . "\n" if $d->{"gateway$suffix"};
    };

    if ($family) {
        $add_addr->($suffix);
    } else {
        $add_addr->('');
        $add_addr->('6');
    }

    my $done = {
        type => 1,
        priority => 1,
        method => 1,
        active => 1,
        exists => 1,
        comments => 1,
        autostart => 1,
        options => 1,
        address => 1,
        netmask => 1,
        gateway => 1,
        broadcast => 1,
        method6 => 1,
        families => 1,
        options6 => 1,
        comments6 => 1,
        address6 => 1,
        netmask6 => 1,
        gateway6 => 1,
        broadcast6 => 1,
        'uplink-id' => 1,
    };

    if (!$first_block) {
        # not printing out options
    } elsif ($d->{type} eq 'bridge') {

        my $ports = $d->{bridge_ports} || 'none';
        $ports =~ s/[;,\s]+/ /g;
        $raw .= "\tbridge-ports $ports\n";
        $done->{bridge_ports} = 1;

        my $br_stp = defined($d->{bridge_stp}) ? $d->{bridge_stp} : 'off';
        my $no_stp = $br_stp eq 'off';

        $raw .= "\tbridge-stp $br_stp\n";
        $done->{bridge_stp} = 1;

        # NOTE: forwarding delay must be 2 <= FD <= 30 if STP is enabled
        if (defined(my $br_fd = $d->{bridge_fd})) {
            if ($no_stp || ($br_fd >= 2 && $br_fd <= 30)) {
                $raw .= "\tbridge-fd $br_fd\n";
            } else {
                # only complain if the user actually set a value, but not for default fallback below
                warn
                    "'$iface': ignoring 'bridge_fd' value '$br_fd', outside of allowed range 2-30\n";
            }
        } elsif ($no_stp) {
            $raw .= "\tbridge-fd 0\n";
        }
        $done->{bridge_fd} = 1;

        if (defined($d->{bridge_vlan_aware})) {
            $raw .= "\tbridge-vlan-aware yes\n";
            my $vlans = $d->{bridge_vids} ? $d->{bridge_vids} : "2-4094";
            $raw .= "\tbridge-vids $vlans\n";
        }
        $done->{bridge_vlan_aware} = 1;
        $done->{bridge_vids} = 1;

        $raw .= "\tmtu $d->{mtu}\n" if $d->{mtu};
        $done->{mtu} = 1;
        $done->{'bridge-disable-mac-learning'} = 1;

    } elsif ($d->{type} eq 'bond') {

        $d->{slaves} =~ s/[;,\s]+/ /g;
        my $slaves = $d->{slaves} || 'none';
        $raw .= "\tbond-slaves $slaves\n";
        $done->{slaves} = 1;

        my $v = defined($d->{'bond_miimon'}) ? $d->{'bond_miimon'} : 100;
        $raw .= "\tbond-miimon $v\n";
        $done->{'bond_miimon'} = 1;

        $v = defined($d->{'bond_mode'}) ? $d->{'bond_mode'} : 'balance-rr';
        $raw .= "\tbond-mode $v\n";
        $done->{'bond_mode'} = 1;

        if (
            $d->{'bond_mode'}
            && $d->{'bond_xmit_hash_policy'}
            && ($d->{'bond_mode'} eq 'balance-xor' || $d->{'bond_mode'} eq '802.3ad')
        ) {
            $raw .= "\tbond-xmit-hash-policy $d->{'bond_xmit_hash_policy'}\n";
        }
        $done->{'bond_xmit_hash_policy'} = 1;

        if ($d->{'bond_mode'} && $d->{'bond_mode'} eq 'active-backup' && $d->{'bond-primary'}) {
            $raw .= "\tbond-primary $d->{'bond-primary'}\n";
        }
        $done->{'bond-primary'} = 1;

        $raw .= "\tmtu $d->{mtu}\n" if $d->{mtu};
        $done->{mtu} = 1;

    } elsif ($d->{type} eq 'vlan') {
        die "$iface: wrong vlan-protocol $d->{'vlan-protocol'}\n"
            if $d->{'vlan-protocol'}
            && $d->{'vlan-protocol'} ne '802.1ad'
            && $d->{'vlan-protocol'} ne '802.1q';

    } elsif ($d->{type} eq 'vxlan') {

        foreach my $k (qw(vxlan-id vxlan-svcnodeip vxlan-physdev vxlan-local-tunnelip)) {
            $raw .= "\t$k $d->{$k}\n" if defined $d->{$k};
            $done->{$k} = 1;
        }

        if ($d->{'vxlan-remoteip'}) {
            foreach my $remoteip (@{ $d->{'vxlan-remoteip'} }) {
                $raw .= "\tvxlan-remoteip $remoteip\n";
            }
            $done->{'vxlan-remoteip'} = 1;
        }

        $raw .= "\tmtu $d->{mtu}\n" if $d->{mtu};
        $done->{mtu} = 1;

    } elsif ($d->{type} eq 'OVSBridge') {

        $raw .= "\tovs_type $d->{type}\n";
        $done->{ovs_type} = 1;

        $raw .= "\tovs_ports $d->{ovs_ports}\n" if $d->{ovs_ports};
        $done->{ovs_ports} = 1;

        $raw .= "\tovs_mtu $d->{mtu}\n" if $d->{mtu};
        $done->{mtu} = 1;

    } elsif ($d->{type} eq 'OVSPort' || $d->{type} eq 'OVSIntPort' || $d->{type} eq 'OVSBond') {

        $d->{autostart} = 0; # started by the bridge

        if (defined($d->{ovs_tag})) {
            &$set_ovs_option($d, tag => $d->{ovs_tag});
        }
        $done->{ovs_tag} = 1;

        if ($d->{type} eq 'OVSBond') {

            $d->{bond_mode} = 'active-backup' if !$d->{bond_mode};

            $ovs_bond_modes->{ $d->{bond_mode} }
                || die "OVS does not support bond mode '$d->{bond_mode}\n";

            if ($d->{bond_mode} eq 'lacp-balance-slb') {
                &$set_ovs_option($d, lacp => 'active');
                &$set_ovs_option($d, bond_mode => 'balance-slb');
            } elsif ($d->{bond_mode} eq 'lacp-balance-tcp') {
                &$set_ovs_option($d, lacp => 'active');
                &$set_ovs_option($d, bond_mode => 'balance-tcp');
            } else {
                &$set_ovs_option($d, lacp => undef);
                &$set_ovs_option($d, bond_mode => $d->{bond_mode});
            }
            $done->{bond_mode} = 1;

            $raw .= "\tovs_bonds $d->{ovs_bonds}\n" if $d->{ovs_bonds};
            $done->{ovs_bonds} = 1;
        }

        $raw .= "\tovs_type $d->{type}\n";
        $done->{ovs_type} = 1;

        if (my $bridge = $d->{ovs_bridge}) {
            if ($ifupdown2) {
                $raw = "auto $iface\n$raw";
            } else {
                $raw = "allow-$bridge $iface\n$raw";
            }

            $raw .= "\tovs_bridge $bridge\n";
            $done->{ovs_bridge} = 1;
        }

        $raw .= "\tovs_mtu $d->{mtu}\n" if $d->{mtu};
        $done->{mtu} = 1;
    }

    if ($first_block) {
        # print other settings
        foreach my $k (sort keys %$d) {
            next if $done->{$k};
            next if !$d->{$k};
            $raw .= "\t$k $d->{$k}\n";
        }
    }

    my $add_options_comments = sub {
        my ($suffix) = @_;

        foreach my $option (@{ $d->{"options$suffix"} }) {
            $raw .= "\t$option\n";
        }

        # add comments
        my $comments = $d->{"comments$suffix"} || '';
        foreach my $cl (split(/\n/, $comments)) {
            $raw .= "#$cl\n";
        }
    };

    if ($family) {
        $add_options_comments->($suffix);
    } else {
        $add_options_comments->('');
        $add_options_comments->('6');
    }

    $raw .= "\n";

    return $raw;
}

sub write_etc_network_interfaces {
    my ($filename, $fh, $config) = @_;
    my $ifupdown2 = -e '/usr/share/ifupdown2/ifupdown2';
    my $raw = __write_etc_network_interfaces($config, $ifupdown2);
    PVE::Tools::safe_print($filename, $fh, encode('UTF-8', $raw));
}

sub __write_etc_network_interfaces {
    my ($config, $ifupdown2) = @_;

    my $ifaces = $config->{ifaces};
    my @options = @{ $config->{options} };

    my $used_ports = {};

    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};

        my ($cidr, $cidr6) = (delete $d->{cidr}, delete $d->{cidr6});
        $d->{address} //= $cidr;
        $d->{address6} //= $cidr6;

        my $ports = '';
        foreach my $k (qw(bridge_ports ovs_ports slaves ovs_bonds)) {
            $ports .= " $d->{$k}" if $d->{$k};
        }

        foreach my $p (PVE::Tools::split_list($ports)) {
            die "port '$p' is already used on interface '$used_ports->{$p}'\n"
                if $used_ports->{$p} && $used_ports->{$p} ne $iface;
            $used_ports->{$p} = $iface;
        }
    }

    # delete unused OVS ports
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        if ($d->{type} eq 'OVSPort' || $d->{type} eq 'OVSIntPort' || $d->{type} eq 'OVSBond') {
            my $brname = $used_ports->{$iface};
            if (!$brname || !$ifaces->{$brname}) {
                $ifaces->{$iface} = {
                    type => 'eth',
                    exists => 1,
                    method => 'manual',
                    families => ['inet'],
                };
                next;
            }
            my $bd = $ifaces->{$brname};
            if ($bd->{type} ne 'OVSBridge') {
                delete $ifaces->{$iface};
                next;
            }
        }
    }

    # create OVS bridge ports
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        if ($d->{type} eq 'OVSBridge' && $d->{ovs_ports}) {
            foreach my $p (split(/\s+/, $d->{ovs_ports})) {
                my $n = $ifaces->{$p};
                die "OVS bridge '$iface' - unable to find port '$p'\n" if !$n;
                $n->{autostart} = 0;
                if ($n->{type} eq 'eth') {
                    $n->{type} = 'OVSPort';
                    $n->{ovs_bridge} = $iface;
                } elsif (
                    $n->{type} eq 'OVSBond'
                    || $n->{type} eq 'OVSPort'
                    || $n->{type} eq 'OVSIntPort'
                ) {
                    $n->{ovs_bridge} = $iface;
                } else {
                    die "interface '$p' is not defined as OVS port/bond\n";
                }

                &$check_mtu($ifaces, $iface, $p);
            }
        }
    }

    # check OVS bond ports
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        if ($d->{type} eq 'OVSBond' && $d->{ovs_bonds}) {
            foreach my $p (split(/\s+/, $d->{ovs_bonds})) {
                my $n = $ifaces->{$p};
                $n->{autostart} = 1;
                die "OVS bond '$iface' - unable to find slave '$p'\n" if !$n;
                die
                    "OVS bond '$iface' - wrong interface type on slave '$p' ('$n->{type}' != 'eth')\n"
                    if $n->{type} ne 'eth';
                &$check_mtu($ifaces, $iface, $p);
            }
        }
    }

    # check bond
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        next if !($d->{type} eq 'bond' && $d->{slaves});

        my $bond_primary_is_slave = undef;
        foreach my $p (split(/\s+/, $d->{slaves})) {
            my $n = $ifaces->{$p};
            $n->{autostart} = 1;

            die "bond '$iface' - unable to find slave '$p'\n" if !$n;
            die
                "bond '$iface' - wrong interface type on slave '$p' ('$n->{type}' != 'eth or bond')\n"
                if ($n->{type} ne 'eth' && $n->{type} ne 'bond');

            $check_mtu->($ifaces, $iface, $p);
            $bond_primary_is_slave = 1 if $d->{'bond-primary'} && $d->{'bond-primary'} eq $p;
        }
        die "bond '$iface' - bond-primary interface is not a slave"
            if $d->{'bond-primary'} && !$bond_primary_is_slave;
    }

    # check vxlan
    my $vxlans = {};
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};

        if ($d->{type} eq 'vxlan' && $d->{'vxlan-id'}) {
            my $vxlanid = $d->{'vxlan-id'};
            die "iface $iface - duplicate vxlan-id $vxlanid already used in $vxlans->{$vxlanid}\n"
                if $vxlans->{$vxlanid};
            $vxlans->{$vxlanid} = $iface;
        }

        my $ips = 0;
        ++$ips if defined $d->{'vxlan-svcnodeip'};
        ++$ips if defined $d->{'vxlan-remoteip'};
        ++$ips if defined $d->{'vxlan-local-tunnelip'};
        if ($ips > 1) {
            die
                "iface $iface - vxlan-svcnodeip, vxlan-remoteip and vxlan-localtunnelip are mutually exclusive\n";
        }

        if (defined($d->{'vxlan-svcnodeip'}) != defined($d->{'vxlan-physdev'})) {
            die "iface $iface - vxlan-svcnodeip and vxlan-physdev must be define together\n";
        }
        #fixme : check if vxlan mtu is lower than 50bytes than physical interface where tunnel is going out
    }

    # check vlan
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        if ($d->{type} eq 'vlan') {

            my $p = undef;
            my $vlanid = undef;

            if ($iface =~ m/^(\S+)\.(\d+)$/) {
                $p = $1;
                $vlanid = $2;
                delete $d->{'vlan-raw-device'} if $d->{'vlan-raw-device'};
                delete $d->{'vlan-id'} if $d->{'vlan-id'};

            } else {
                die "missing vlan-raw-device option" if !$d->{'vlan-raw-device'};
                $p = $d->{'vlan-raw-device'};

                if ($iface =~ m/^vlan(\d+)$/) {
                    $vlanid = $1;
                    delete $d->{'vlan-id'} if $d->{'vlan-id'};
                } else {
                    die "custom vlan interface name need ifupdown2" if !$ifupdown2;
                    die "missing vlan-id option" if !$d->{'vlan-id'};
                    $vlanid = $d->{'vlan-id'};
                }
            }
            my $n = $ifaces->{$p};

            die "vlan '$iface' - vlan-id $vlanid should be <= 4094\n" if $vlanid > 4094;
            die "vlan '$iface' - unable to find parent '$p'\n"
                if !$n;

            if (
                $n->{type} ne 'eth'
                && $n->{type} ne 'bridge'
                && $n->{type} ne 'bond'
                && $n->{type} ne 'vlan'
            ) {
                die "vlan '$iface' - wrong interface type on parent '$p' "
                    . "('$n->{type}' != 'eth|bond|bridge|vlan' )\n";
            }

            &$check_mtu($ifaces, $p, $iface);

        }
    }

    # check uplink
    my $uplinks = {};
    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};
        if (my $uplinkid = $d->{'uplink-id'}) {
            die
                "iface '$iface' - uplink-id $uplinkid is only allowed on physical and linux bond interfaces\n"
                if $d->{type} ne 'eth' && $d->{type} ne 'bond';

            die
                "iface '$iface' - uplink-id $uplinkid is already assigned on '$uplinks->{$uplinkid}'\n"
                if $uplinks->{$uplinkid};

            $uplinks->{$uplinkid} = $iface;
        }
    }

    # check bridgeport option
    my $bridgeports = {};
    my $bridges = {};
    my $ifaces_copy = {%$ifaces};
    foreach my $iface (keys %$ifaces_copy) {
        my $d = $ifaces_copy->{$iface};
        if ($d->{type} eq 'bridge') {
            foreach my $p (split(/\s+/, $d->{bridge_ports} // '')) {
                if ($p =~ m/(\S+)\.(\d+)$/) {
                    my $vlanparent = $1;
                    if (!defined($ifaces_copy->{$p})) {
                        $ifaces_copy->{$p}->{type} = 'vlan';
                        $ifaces_copy->{$p}->{method} = 'manual';
                        $ifaces_copy->{$p}->{method6} = 'manual';
                        $ifaces_copy->{$p}->{mtu} = $ifaces_copy->{$vlanparent}->{mtu}
                            if defined($ifaces_copy->{$1}->{mtu});
                    }
                }
                my $n = $ifaces_copy->{$p};
                die "bridge '$iface' - unable to find bridge port '$p'\n" if !$n;
                die "iface $p - ip address can't be set on interface if bridged in $iface\n"
                    if ($n->{method} && $n->{method} eq 'static' && $n->{address} ne '0.0.0.0')
                    || ($n->{method6} && $n->{method6} eq 'static' && $n->{address6} ne '::');
                &$check_mtu($ifaces_copy, $p, $iface);
                $bridgeports->{$p} = $iface;
            }
            $bridges->{$iface} = $d;
        }
    }

    foreach my $iface (keys %$ifaces) {
        my $d = $ifaces->{$iface};

        foreach my $k (
            qw(bridge-learning bridge-arp-nd-suppress bridge-unicast-flood bridge-multicast-flood bridge-access)
        ) {
            die
                "iface $iface - $k: bridge port specific options can be used only on interfaces attached to a bridge\n"
                if $d->{$k} && !$bridgeports->{$iface};
        }

        if ($d->{'bridge-access'} && !$bridges->{ $bridgeports->{$iface} }->{bridge_vlan_aware}) {
            die
                "iface $iface - bridge-access option can be only used if interface is in a vlan aware bridge\n";
        }
    }

    my $raw = <<'NETWORKDOC';
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

NETWORKDOC

    my $printed = {};

    my $if_type_hash = {
        loopback => 100000,
        dummy => 100000,
        eth => 200000,
        OVSPort => 200000,
        OVSIntPort => 300000,
        OVSBond => 400000,
        bond => 400000,
        bridge => 500000,
        OVSBridge => 500000,
        vlan => 600000,
        vxlan => 600000,
    };

    my $lookup_type_prio = sub {
        my ($iface, $ifaces) = @_;

        my ($rootiface, @rest) = split(/[.:]/, $iface);
        my $childlevel = scalar(@rest);
        my $type = $ifaces->{$rootiface}->{type};
        return if !$type || $type eq 'unknown';

        return $if_type_hash->{$type} + $childlevel;
    };

    foreach my $iface (
        sort {
            my $ref1 = $ifaces->{$a};
            my $ref2 = $ifaces->{$b};
            my $tp1 = &$lookup_type_prio($a, $ifaces);
            my $tp2 = &$lookup_type_prio($b, $ifaces);

            # Only recognized types are in relation to each other. If one type
            # is unknown then only consider the interfaces' priority attributes.
            $tp1 = $tp2 = 0 if !defined($tp1) || !defined($tp2);

            my $p1 = $tp1 + ($ref1->{priority} // 50000);
            my $p2 = $tp2 + ($ref2->{priority} // 50000);

            return $p1 <=> $p2 if $p1 != $p2;

            return $a cmp $b;
        } keys %$ifaces
    ) {
        next if $printed->{$iface};
        my $d = $ifaces->{$iface};
        my $pri = $d->{priority} // 0;
        if (@options && $options[0]->[0] < $pri) {
            do {
                $raw .= (shift @options)->[1] . "\n";
            } while (@options && $options[0]->[0] < $pri);
            $raw .= "\n";
        }

        $printed->{$iface} = 1;
        if ($d->{autostart}) {
            if ($d->{type} eq 'OVSBridge' && !$ifupdown2) {
                # cannot use 'auto' for OVS, would add race with systemd ifup@.service
                $raw .= "allow-ovs $iface\n";
            } else {
                $raw .= "auto $iface\n";
            }
        }

        # if 'inet6' is the only family
        if (
            scalar($d->{families}->@*) == 1
            && defined($d->{families}->[0])
            && $d->{families}->[0] eq 'inet6'
        ) {
            $d->{comments6} = delete $d->{comments};
        }

        my $i = 0; # some options should be printed only once
        $raw .= __interface_to_string($iface, $d, $_, !$i++, $ifupdown2)
            foreach @{ $d->{families} };
    }

    $raw .= $_->[1] . "\n" foreach @options;
    return $raw;
}

register_file(
    'interfaces',
    "/etc/network/interfaces",
    \&read_etc_network_interfaces,
    \&write_etc_network_interfaces,
);

sub read_iscsi_initiatorname {
    my ($filename, $fd) = @_;

    while (defined(my $line = <$fd>)) {
        if ($line =~ m/^InitiatorName=(\S+)$/) {
            return $1;
        }
    }

    return 'undefined';
}

register_file('initiatorname', "/etc/iscsi/initiatorname.iscsi", \&read_iscsi_initiatorname);

1;