# Wrappers for iproute2 utilities
#
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
# 
# 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.
# 
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2008 Vyatta, Inc.
# All Rights Reserved.
# **** End License ****

package VyattaQosUtil;
require Exporter;
@EXPORT	= qw/getRate getBurstSize getProtocol getDsfield getIfIndex interfaceRate/;
use strict;

sub get_num  {
    use POSIX qw(strtod);
    my ($str) = @_;
    $str =~s/^\s+//;
    $str =~s/\s+$//;

    $! = 0;
    my ($num, $unparsed) = strtod($str);
    if (($unparsed == length($str)) || $!) {
	return;	# undefined (bad input)
    }

    if ($unparsed > 0) { return $num, substr($str, -$unparsed); }
    else	       { return $num; }
}

## get_rate("10mbit")
# convert rate specification to number
# from tc/tc_util.c

my %rates = (
    'bit'	=> 1,
    'kibit'	=> 1024,
    'kbit'	=> 1000.,
    'mibit'	=> 1048576.,
    'mbit'	=> 1000000.,
    'gibit'	=> 1073741824.,
    'gbit'	=> 1000000000.,
    'tibit'	=> 1099511627776.,
    'tbit'	=> 1000000000000.,
    'bps'	=> 8.,
    'kibps'	=> 8192.,
    'kbps'	=> 8000.,
    'mibps'	=> 8388608.,
    'mbps'	=> 8000000.,
    'gibps'	=> 8589934592.,
    'gbps'	=> 8000000000.,
    'tibps'	=> 8796093022208.,
    'tbps'	=> 8000000000000.,
);

sub getRate {
    my $rate = shift;
    my ($num, $suffix) = get_num($rate);

    defined $num
	or die "$rate is not a valid bandwidth (not a number)\n";
    ($num >= 0)
	or die "$rate is not a valid bandwidth (negative value)\n";

    if (defined $suffix) {
	my $scale = $rates{lc $suffix};

	if (defined $scale) {
	    return $num * $scale;
	}

	die "$rate is not a valid bandwidth (unknown scale suffix)\n";
    } else {
	# No suffix implies Kbps just as IOS
	return $num * 1000;
    }
}

# Default time units for tc are usec.
my %timeunits = (
    's'		=> 1000000,
    'sec'	=> 1000000,
    'secs'	=> 1000000,
    'ms'	=> 1000,
    'msec'	=> 1000,
    'msecs'	=> 1000,
    'us'	=> 1,
    'usec'	=> 1,
    'usecs'	=> 1,
);

sub getTime {
    my $time = shift;
    my ($num, $suffix) = get_num($time);

    defined $num
	or die "$time is not a valid time interval (not a number)\n";
    ($num >= 0)
	or die "$time is not a valid time interval (negative value)\n";

    if (defined $suffix) {
	my $scale = $timeunits{lc $suffix};

	if (defined $scale) {
	    return $num * $scale;
	}

	die "$time is not a valid time interval (unknown suffix)\n";
    } else {
	# No suffix implies ms
	return $num * 1000;
    }
}



my %scales = (
    'b'		=> 1,
    'k'		=> 1024,
    'kb'	=> 1024,
    'kbit'	=> 1024/8,
    'm'		=> 1024*1024,
    'mb'	=> 1024*1024,
    'mbit'	=> 1024*1024/8,
    'g'		=> 1024*1024*1024, 
    'gb'	=> 1024*1024*1024,
);

sub getBurstSize {
    my $size = shift;
    my ($num, $suffix) = get_num($size);

    defined $num 
	or die "$size is not a valid burst size (not a number)\n";

    ($num >= 0)
	or die "$size is not a valid burst size (negative value)\n";

    if (defined $suffix) {
	my $scale = $scales{lc $suffix};
	defined $scale or
	    die "$size is not a valid burst size (unknown scale suffix)\n";
	$num *= $scale;
    }

    return $num;
}

sub getProtocol {
    my ($str) = @_;

    defined $str or return;
    if ($str =~ /^([0-9]+)|(0x[0-9a-fA-F]+)$/) {
	if ($str < 0 || $str > 255) {
	    die "$str is not a valid protocol number\n";
	}
	return $str;
    }

    my ($name, $aliases, $proto) =  getprotobyname($str);
    (defined $proto)  or die "\"$str\" unknown protocol\n";
    return $proto;
}

# Parse /etc/iproute/rt_dsfield 
# return a hex string "0x10" or undefined
sub getDsfield {
    my ($str) = @_;
    my $match = undef;
    my $dsFileName = '/etc/iproute2/rt_dsfield';
    
    defined $str or return;

    # match number (or hex)
    if ($str =~ /^([0-9]+)|(0x[0-9a-fA-F]+)$/) {
	if ($str < 0 || $str > 63) {
	    die "$str is not a valid DSCP value\n";
	}
	# convert DSCP value to header value used by iproute
	return $str << 2;
    }

    open my $ds, '<', $dsFileName || die "Can't open $dsFileName, $!\n";
    while (<$ds>) {
	next if /^#/;
	chomp;
	my ($value, $name) = split;
	if ($str eq $name) {
	    $match = $value;
	    last;
	}
    }
    close($ds) or die "read $dsFileName error\n";
    
    (defined $match) or die "\"$str\" unknown DSCP value\n";
    return $match;
}

sub getIfIndex {
    my ($str) = @_;

    defined $str or return;
    open my $sysfs, "<", "/sys/class/net/$str/ifindex" || die "Unknown interface $str\n";
    my $ifindex = <$sysfs>;
    close($sysfs) or die "read sysfs error\n";
    chomp $ifindex;
    return $ifindex;
}


## interfaceRate("eth0")
# return result in bits per second
sub interfaceRate {
    my ($interface) = @_;
    my $speed;
    my $config = new VyattaConfig;

    $config->setLevel("interfaces ethernet");
    if ($config->exists("$interface")) {
	$speed  = $config->returnValue("$interface speed");
	if (defined($speed) && $speed ne "auto") {
	    return $speed * 1000000;
	}
    } 

    # During boot it may take time for auto-negotiation
    for (my $retries = 0; $retries < 5; $retries++) {
	$speed = ethtoolRate($interface);
	if (defined $speed) {
	    return $speed;
	}
	sleep 1;
    }

    warn "Could not determine speed for $interface, assuming 100mbit\n";
    return 100 * 1000000;
}

## ethtoolRate("eth0")
# Fetch actual rate using ethtool and format to valid tc rate
sub ethtoolRate {
    my $dev = shift;
    my $rate = undef;

    # Get rate of real device (ignore vlan)
    $dev =~ s/\.[0-9]+$//;

    open(my $ethtool, "/usr/sbin/ethtool $dev 2>/dev/null |")
 	or die "ethtool failed: $!\n";

    # ethtool produces:
    #
    # Settings for eth1:
    # Supported ports: [ TP ]
    # ...
    # Speed: 1000Mb/s
    while (<$ethtool>) {
	my @line = split;
	if ($line[0] =~ /^Speed:/) {
	    $rate = $line[1];
	    $rate =~ s#Mb/s#000000#;
	    last;
	}
    }
    close $ethtool;
    return $rate;
}