ifenslave

#!/bin/sh

[ "$VERBOSITY" = 1 ] && set -x

[ "$ADDRFAM" = meta ] && exit 0

add_master()
{
	# Return if $BOND_MASTER is already a bonding interface.
	[ -f "/sys/class/net/$BOND_MASTER/bonding/slaves" ] && return

	# If the bonding module is not yet loaded, load it.
	if [ ! -r /sys/class/net/bonding_masters ]; then
		modprobe -q bonding

		FAILED=1
		echo "Waiting for bonding kernel module to be ready (will timeout after 5s)"
		count=0
		while [ "$count" -lt "50" ]; do
			if [ -r /sys/class/net/bonding_masters ]; then
				FAILED=0
				break
			fi
			sleep 0.1
			count=$(($count+1))
		done

		if [ "$FAILED" = "1" ]; then
			echo "/sys/class/net/bonding_masters doesn't exist. Unable to create $BOND_MASTER"
			exit 1
		fi

	fi

	# Create the master interface.
	if ! grep -sq "\\<$BOND_MASTER\\>" /sys/class/net/bonding_masters; then
		echo "+$BOND_MASTER" > /sys/class/net/bonding_masters
	fi
}

sysfs_change_down()
{
	# Called with :
	# $1 = basename of the file in bonding/ to write to.
	# $2 = value to write. Won't write if $2 is empty.
	if [ "$2" ] ; then
		# If the value we plan to write is different from the current one...
		if ! grep -sq "\\<$2\\>" "/sys/class/net/$BOND_MASTER/bonding/$1" ; then
			# ...and the master is up...
			if ip link show "$BOND_MASTER" | grep -sq '[<,]UP[,>]' ; then
				# ...bring the master down.
				ip link set dev "$BOND_MASTER" down
			fi
		fi
		sysfs "$1" "$2"
	fi
}

sysfs()
{
	# Called with :
	# $1 = basename of the file in bonding/ to write to.
	# $2 = value to write. Won't write if $2 is empty.
	if [ "$2" ] ; then
		echo "$2" > "/sys/class/net/$BOND_MASTER/bonding/$1"
		return $?
	fi
	return 0
}

sysfs_add()
{
	#??Called with :
	# $1 = target filename.
	# $2 = values to write.
	for value in $2; do
		# Do not add $2 to $1 if already present.
		if ! grep -sq "\\<$value\\>" /sys/class/net/$BOND_MASTER/bonding/$1
		then
		    sysfs "$1" "+$value"
		fi 
	done
}

# early_setup_master is the place where we do master setup that need to be done before enslavement.
early_setup_master()
{
	# Warning: the order in wich we write into the sysfs files is important.
	# Double check in drivers/net/bonding/bond_sysfs.c in linux kernel source tree 
	# before changing anything here.

	# fail_over_mac must be set before enslavement of any slaves.
	sysfs fail_over_mac "$IF_BOND_FAIL_OVER_MAC"
}

# late_setup_master runs actions that need to happen after enslavement
late_setup_master()
{
	# primary must be set after mode (because only supported in some modes) and after enslavement.
	# The first slave in bond-primary found in current slaves becomes the primary.
	# If no slave in bond-primary is found, then primary does not change.
	for slave in $IF_BOND_PRIMARY ; do
		if grep -sq "\\<$slave\\>" "/sys/class/net/$BOND_MASTER/bonding/slaves" ; then
			sysfs primary "$slave"
			break
		fi
	done

	# primary_reselect should be set after mode (because only supported in some modes), after enslavement
	# and after primary. This is currently (2.6.35-rc1) not enforced by the bonding driver, but it is
	# probably safer to do it in that order.
	sysfs primary_reselect "$IF_BOND_PRIMARY_RESELECT"

	# queue_id must be set after enslavement.
	for iface_queue_id in $IF_BOND_QUEUE_ID
	do
		sysfs iface_queue_id $iface_queue_id
	done

	# active_slave must be set after mode and after enslavement.
	# The slave must be up and the underlying link must be up too.
	# FIXME: We should have a way to write an empty string to active_slave, to set the active_slave to none.
	if [ "$IF_BOND_ACTIVE_SLAVE" ] ; then
		# Need to force interface up before. Bonding will refuse to activate a down interface.
		ip link set "$IF_BOND_ACTIVE_SLAVE" up
		sysfs active_slave "$IF_BOND_ACTIVE_SLAVE"
	fi
}

enslave_slaves()
{
	case "$BOND_SLAVES" in
		none)
			BOND_SLAVES=""
			;;
		all)
			BOND_SLAVES=""
			for device in /sys/class/net/*/device; do
				name=$(basename ${device%*/device})
				[ -n "$BOND_SLAVES" ] && BOND_SLAVES="$BOND_SLAVES $name" || BOND_SLAVES="$name"
			done
			AUTOIF="yes"
			;;
	esac

	[ "$VERBOSITY" = 1 ] && v=-v
	for slave in $BOND_SLAVES ; do
		if ( [ "$AUTOIF" ] && ifquery --state $slave ) ; then
			echo "Not enslaving interface $slave since it is already configured"
		else
			# Ensure $slave is down.
			ip link set "$slave" down 2>/dev/null
			if ! sysfs_add slaves "$slave" 2>/dev/null ; then
				echo "Failed to enslave $slave to $BOND_MASTER. Is $BOND_MASTER ready and a bonding interface ?" >&2
			else
				# Bring up slave if it is the target of an allow-bondX stanza.
				# This is usefull to bring up slaves that need extra setup.
				if [ -z "$(which ifquery)" ] || ifquery --allow \"$BOND_MASTER\" --list | grep -q $slave; then
					ifup $v --allow "$BOND_MASTER" "$slave"
				fi
			fi
		fi
	done
}

setup_master()
{
	# Warning: the order in wich we write into the sysfs files is important.
	# Double check in drivers/net/bonding/bond_sysfs.c in linux kernel source tree 
	# before changing anything here.

	# use_carrier can be set anytime.
	sysfs use_carrier "$IF_BOND_USE_CARRIER"
	# num_grat_arp can be set anytime.
	sysfs num_grat_arp "$IF_BOND_NUM_GRAT_ARP"
	# num_unsol_na can be set anytime.
	sysfs num_unsol_na "$IF_BOND_NUM_UNSOL_NA"

	# xmit_hash_policy can be set anytime.
	# Changing xmit_hash_policy requires $BOND_MASTER to be down.
	sysfs_change_down xmit_hash_policy "$IF_BOND_XMIT_HASH_POLICY"

	# arp_ip_target must be set before arp_interval.
	sysfs_add arp_ip_target "$IF_BOND_ARP_IP_TARGET"
	sysfs arp_interval "$IF_BOND_ARP_INTERVAL"

	# miimon must be set before updelay and downdelay.
	sysfs miimon "$IF_BOND_MIIMON"
	sysfs downdelay "$IF_BOND_DOWNDELAY"
	sysfs updelay "$IF_BOND_UPDELAY"

	# Changing ad_select requires $BOND_MASTER to be down.
	sysfs_change_down ad_select "$IF_BOND_AD_SELECT"

	# Changing mode requires $BOND_MASTER to be down.
	# Mode should be set after miimon or arp_interval, to avoid a warning in syslog.
	sysfs_change_down mode "$IF_BOND_MODE"

	# packets_per_slave allowed for mode balance-rr only.
	sysfs packets_per_slave "$IF_BOND_PACKETS_PER_SLAVE"

	# arp_validate must be after mode (because mode must be active-backup).
	sysfs arp_validate "$IF_BOND_ARP_VALIDATE"

	# lacp_rate must be set after mode (because mode must be 802.3ad).
	# Changing lacp_rate requires $BOND_MASTER to be down.
	sysfs_change_down lacp_rate "$IF_BOND_LACP_RATE"

	# Finally bring the bond up, note that without a slave it won't be usable though
	ip link set dev $BOND_MASTER up
}

# Option slaves deprecated, replaced by bond-slaves, but still supported for backward compatibility.
IF_BOND_SLAVES=${IF_BOND_SLAVES:-$IF_SLAVES}

if [ "$IF_BOND_MASTER" ] ; then
	BOND_MASTER="$IF_BOND_MASTER"
	BOND_SLAVES="$IFACE"
else
	if [ "$IF_BOND_SLAVES" ] ; then
		BOND_MASTER="$IFACE"
		BOND_SLAVES="$IF_BOND_SLAVES"
	fi
fi

# Exit if nothing to do...
[ -z "$BOND_MASTER$BOND_SLAVES" ] && exit

# Always try to create the master, returns if already exists
add_master

if [ "$BOND_MASTER" = "$IFACE" ]; then
	# Setup the master interface
	early_setup_master
	setup_master

	# Indicate that we're done setting up the master
	# this is required as ifstate is modified at the beginning
	# of the interface setup, not at the end
	touch /run/network/ifenslave.$IFACE

	# Wait for a slave to join, continuing without a slave
	# would make dhclient, vconfig or brctl fail, so better wait
	# Timeout after a minute
	FAILED=1
	echo "Waiting for a slave to join $BOND_MASTER (will timeout after 60s)"
	count=0
	while [ "$count" -lt "600" ]; do
		if [ -n "$(cat /sys/class/net/$BOND_MASTER/bonding/slaves)" ]; then
			FAILED=0
			break
		fi
		sleep 0.1
		count=$(($count+1))
	done
	if [ "$FAILED" = "1" ]; then
		echo "No slave joined $BOND_MASTER, continuing anyway"
	else
		# Trigger the udev bridging hook to bridge the bond if needed
		if [ -x /lib/udev/bridge-network-interface ]; then
			INTERFACE=$BOND_MASTER /lib/udev/bridge-network-interface
		fi

		# Trigger the udev bridging hook to tag the bond if needed
		if [ -x /lib/udev/vlan-network-interface ]; then
			INTERFACE=$BOND_MASTER /lib/udev/vlan-network-interface
		fi
	fi
else
	# Wait for the master to be ready
	[ ! -f /run/network/ifenslave.$BOND_MASTER ] && echo "Waiting for bond master $BOND_MASTER to be ready"
	while :; do
		if [ -f /run/network/ifenslave.$BOND_MASTER ]; then
			break
		fi
		sleep 0.1
	done

	# Only setup one slave at once
	BOND_SLAVES=$IFACE enslave_slaves

	# Call late_setup_master every time we add a slave as we don't have a way to know
	# when all the slaves are up
	BOND_SLAVES=$IFACE late_setup_master
fi
exit 0