Alternative to ifenslave-2.6 for setting up ether bonding

gistfile1.txt

#!/bin/sh

# 2014, j.grassler@syseleven.de

# This script is mostly /etc/network/if-pre-up.d/ifenslave with the deadlocks
# and some flexibility ripped out. It is meant to be called as pre-up script for a
# bonding interface. Make sure not to set any bond-master or bond-slaves
# directives in /etc/network/interfaces to prevent the regular ifenslave script
# from interfering. Feel free to set other bonding related options. This script
# will honour them in the same manner as the regular ifenslave script. In
# addition it will honour the following extra options:
#  
#   mtu      the interface's MTU.
#
# All command line arguments are treated as slave interfaces to add to the
# bonding interfaces.
#
# interfaces(5) usage example:
#
# auto eth0  # First bond slave
# iface eth0 inet static
#   address 0.0.0.0
#
# iface eth1 inet static  # First bond slave
#   address 0.0.0.0
#
# auto bond0
# iface bond0 inet static
#   mtu 4000
#   up /etc/network/local/sys11bonding

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


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)"
		for i in $(seq 50); do
			if [ -r /sys/class/net/bonding_masters ]; then
				FAILED=0
				break
			fi
			sleep 0.1
		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
}

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"

	# 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

  if [ -n "$IF_MTU" ]; then
	  ip link set dev $BOND_MASTER mtu $IF_MTU
  else
	  ip link set dev $BOND_MASTER up
  fi
}

BOND_MASTER=${IFACE}
SLAVES=$*

if [ $MODE = 'start' ]; then
  add_master   # creates bond0 device
  setup_master # sets device options in sysfs

  ifenslave ${IFACE} ${SLAVES}  # Adds slaves to device
  touch /run/network/ifenslave.$BOND_MASTER
else
    exit 0   # Make sure we only take action when interfaces are brought up.
fi

exit 0