#!/bin/bash
# **** 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) 2007 Vyatta, Inc.
# All Rights Reserved.
#
# Authors:      Tom Grennan <tgrennan@vyatta.com>
#               Bob Gilligan <gilligan@vyatta.com>
# Description:	search Vyatta config for interface name given address
#
# **** End License ****

progname=${0##*/}
debug=
match=
attr_address=0:0:0:0:0:0
declare -i ethn=0
udev_persistent_net_rules_file="/etc/udev/rules.d/70-persistent-net.rules"

# Set log_file to "/dev/null" to turn off debugging
log_file="/tmp/vnn_log"

test -r /etc/default/vyatta && source /etc/default/vyatta

# process command line variable overrides

for arg ; do
    case "$arg" in
    --debug )
	debug=echo
	;;
    --*=* )
	arg=${arg#--}
	eval ${arg%=*}=\"${arg#*=}\"
	;;
    *=* )
	eval ${arg%=*}=\"${arg#*=}\"
	;;
    *:*:*:*:*:* )
	attr_address=$arg
	;;
    * )
	kname=$arg
	;;
    esac
done

: ${vyatta_prefix:=/opt/vyatta}
: ${vyatta_sbindir:=${vyatta_prefix}/sbin}
: ${vyatta_sysconfdir:=${vyatta_prefix}/etc}
: ${BOOTFILE:=${vyatta_sysconfdir:-/opt/vyatta/etc}/config/config.boot}
: ${DEFAULT_BOOTFILE:=${vyatta_sysconfdir:-/opt/vyatta/etc}/config.boot.default}

shopt -s extglob nullglob

# load cfg_eth_hwid array from config file as follows
# interface {
# ...
#     ethernet eth# {
#     ...
#	 hw-id XX:XX:XX:XX:XX:XX
#     ...
#     }
# }
#
# cfg_eth_hwid=( "eth#=xx:xx:xx:xx:xx:xx" ... )

declare -a cfg_net_hwid=( $( sed -ne '
    /^interfaces {/,/^}/ {
	/^ *ethernet eth[0-9]* {/,/^    $/ {
	    /^ *ethernet/ {
		s/\r//
		s/.* eth\([0-9]\+\) {$/ eth\1=/
# hold interface name
		h
	    }
	    /^.*hw-id:\?/ {
# translate field name
		s/\r//
		s/.*hw-id:\? *//
# tolower hex mac address
		y/ABCDEF/abcdef/
# exchange hold and pattern space
		x
# concatenate hold and pattern
		G
		s/\n//p
	    }
	}
    }' $BOOTFILE ))

finish ()
{
    local cmd=$1 name=$2 address=$3

    # The output from this program tells udev what name to give this device
    echo $name

    # This file tells rl_system startup script how to update the Vyatta
    # config file.
    touch /tmp/${progname}_${cmd}_${name}_${address} &> /dev/null

    # Remove entry for this MAC addr from the standard udev generated
    # config file, if it exists, so it doesn't rename the interface
    # out from under us.  Remove the subject line plus the comment
    # line above it
    if [ -e  $udev_persistent_net_rules_file ]; then
	sed -i -e "/^#/N;/${address}/d" $udev_persistent_net_rules_file
    fi

    exit $?
}

# Determine whether variable "ethn" conflicts with an ethernet unit
# number that was assigned in previous runs of this script
ethn_conflicts()
{
    # Return value 1 (failure) means no conflicts found.
    # Return value 0 (success) means conflicts were found.
    conflicts=1

    echo "`date`: ethn_conflicts is checking if $ethn has conflicts" >> $log_file
    # Generate list of ethernet unit numbers assigned previously by this script
    used_ethn=""
    for filename in /tmp/vyatta_net_name* ; do
	if [ -e $filename ]; then
	    # strip off everything before the unit number
	    unit=${filename##*vyatta_net_name_*_eth}
	    # strip off everything after the unit number
	    unit=${unit%%_*}
	    # add unit number from this file to the list
	    used_ethn="$used_ethn $unit"
	fi
    done

    echo "`date`: ethn_conflicts: about to run check" >> $log_file

    for this_ethn in $used_ethn ; do
	if [ $ethn -eq $this_ethn ]; then
	    echo "`date`: ethn $ethn conflicts with previously configured $this_ethn" >> $log_file
	    conflicts=0
	    break
	fi
    done

    echo "`date`: ethn_conflicts for ethn $ethn returns $conflicts" >> $log_file
    # return value (exit status) is true, i.e. 0, if there is a conflict
    return $conflicts
}


#
# Find an ethernet unit number that is neither listed in the config
# file nor assigned by this script in earlier runs.
get_free_ethn()
{
    # list of ethernet unit numbers assigned previously by this script
    used_ethn=""
    for filename in /tmp/vyatta_net_name* ; do
	if [ -e $filename ]; then
	    # strip off everything before the unit number
	    unit=${filename##*vyatta_net_name_*_eth}
	    # strip off everything after the unit number
	    unit=${unit%%_*}
	    # add unit number from this file to the list
	    used_ethn="$used_ethn $unit"
	fi
    done

    # Counting up from 0, try to find a free ethernet unit number
    found=0
    for ((ethn_to_use=0 ;  ; ethn_to_use+=1)) ; do
	found=1
	# Check to see if this one is in the config file

	echo "`date`: get_free_ethn: cfg_net_hwid is ${cfg_net_hwid[@]}" >> $log_file

	for name_hwid in ${cfg_net_hwid[@]} ; do
	    name=${name_hwid%=*}
            this_ethn=${name/eth/}
	    echo "`date`: get_free_ethn 1 comparing $ethn_to_use vs $this_ethn" >> $log_file
	    if [ $ethn_to_use -eq $this_ethn ]; then
		found=0
		break
	    fi
	done

	if [ $found -eq 0 ]; then
	    continue
	fi

	echo "`date`: get_free_ethn: used_ethn is $used_ethn" >> $log_file

	# Check to see if this script has assigned this unit number already
	for this_ethn in $used_ethn ; do
	    echo "`date`: get_free_ethn 2 comparing $ethn_to_use vs $this_ethn" >> $log_file
	    if [ $ethn_to_use -eq $this_ethn ]; then
		found=0
		break
	    fi
	done

	if [ $found -eq 1 ]; then
	    break
	fi
    done

    # The return value
    ethn=$ethn_to_use

    echo "`date`: get_free_ethn found $ethn_to_use" >> $log_file
}

# Run with lock held to protect atomicity of access to assigned ethn file
( flock 200

touch $log_file

echo "`date`: vyatta_net_name $kname $attr_address" >> $log_file

if [ ! -f $BOOTFILE ] ; then
    cp $DEFAULT_BOOTFILE $BOOTFILE
    chgrp vyattacfg $BOOTFILE 
    chmod 660 $BOOTFILE
fi

for name_hwid in ${cfg_net_hwid[@]} ; do
    name=${name_hwid%=*}
    hwid=${name_hwid#*=}
    ethn=${name/eth/}
    echo "`date`: Checking $name_hwid against $kname $attr_address" >> $log_file

    if [ "$hwid" == "$attr_address" ] ; then
	# The MAC addr of this interface matches an entry in the config
	# file.  We mod the config file interface sub-block in case it
	# is missing.

	echo "`date`: finish 1: mod $name $attr_address" >> $log_file

	finish mod $name $attr_address
    fi

    if [ "$name" = "$kname" ]; then
	# The kernel name matches an entry in the config file.  Save the
        # config file entry for later examination.
	
	match=$name_hwid
    fi
done

if [ -z "$kname" ]; then
    exit 1
fi

# We have not found a matching hwid in the config file.  See if we can use
# the kernel name.

if [ -z "$match" ] ; then
    # The kernel interface name is not listed in the config file.
    # If the kernel's name is in the standard "ethN" format, and doesn't
    # conflict with any other name we've used, then
    # we can just go ahead and use the kernel's name.  If not, then
    # we will generate a name in the standard format that does not
    # conflict with any names in the config file, or any other names
    # that we have seen.

    non_std_kname=${kname##eth+([0-9])}
    if [ -z "$non_std_kname" ]; then
	# kname is in standard format, so we get the unit number from it.
	ethn=${kname/eth/}

	# We can use this unit number unless it happens to conflict
	# with one we have already assigned.
	if ethn_conflicts ; then
	    echo "`date`: kname $kname conflicts with already assigned unit" >> $log_file
	    get_free_ethn
	fi
    else
	# kname is not in standard format, so we have to generate
	# a unit number
	echo "`date`: kname $kname is non-standard format" >> $log_file
	get_free_ethn
    fi

    echo "`date`: finish 2: add eth$ethn $attr_address" >> $log_file

    finish add eth$ethn $attr_address

elif [ -z "${match#*=}" ] ; then
    # The config file has this interface but the sub-block is missing the hwid
    # field, so we use the kernel name.  In this case, we know that the
    # kernel name is in the standard format because it matched an entry
    # in the config file, and all entries in the config file are in standard
    # format.  This will cause the hwid for this NIC to be added to the
    # entry in the config file.

    echo "`date`: finish 3: mod $kname $attr_address" >> $log_file

    finish mod $kname $attr_address

else
    # The config file has this interface name, but the mac address
    # that of this NIC.  This indicates that the device is either a
    # replacement or new NIC that is being detected earlier than the device
    # configured with this name. Since we don't know which case it is,
    # we must generate a new unit number.
    get_free_ethn
    
    echo "`date`: finish 4: add eth$ethn $attr_address" >> $log_file

    finish add eth$ethn $attr_address
fi

# Should never get here.  If this shows up in the log file, something
# is wrong!
echo "`date`: no finish: kname = $kname, attr_attr = $attr_address, match = $match" >> $log_file

) 200> /tmp/vnn_lock

# Local Variables:
# mode: shell-script
# sh-indentation: 4
# End: