#!/bin/sh

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

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

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 "$2" > "/sys/class/net/$IFACE/master/bonding/$1"
		return $?
	fi
	return 0
}

# If the stanza bond-give-a-chance is set for a slave interface,
# then force $IFACE to be the primary for some time, then restore the primary to its previous value.

# This stanza is designed to workaround a bug in wpa_supplicant, when used with bonding :

# wpa_supplicant expects Wi-Fi authentication packets on the bond interface, but also sends Wi-Fi authentication packets on the bond interface.
# If the active interface is not the Wi-Fi interface at the time wpa_supplicant tries to authenticate, the Wi-Fi AP won't receive anything, causing the authentication to fail.

# In order for the Wi-Fi authentication to succeed, one needs to give a chance to the Wi-Fi interface to send authentication packets.
# "bond-give-a-chance 10" will set the Wi-Fi interface as the primary interface for 10 seconds, then restore the previous primary interface.
# This is supposed to be enough to give a chance to Wi-Fi to authenticate properly.

if [ "$IF_BOND_GIVE_A_CHANCE" ] ; then
	read -r primary < "/sys/class/net/$IFACE/master/bonding/primary"
	# Set the temporary primary.
	sysfs primary "$IFACE"

	# Wait for the link to be setup, but not longer that $IF_BOND_GIVE_A_CHANGE seconds.
	while [ "$IF_BOND_GIVE_A_CHANCE" -gt 0 ] ; do
		if ip link show "$IFACE" | grep -sq 'state UP'; then
			break
		fi
		sleep 1
		IF_BOND_GIVE_A_CHANCE=$((IF_BOND_GIVE_A_CHANCE - 1))
	done

	# Restore the previous primary.
	sysfs primary "$primary"
fi