#!/bin/sh

set -e

# Copyright (C) 2012, 2020 Natanael Copa <ncopa@alpinelinux.org>
# Copyright (C) 2020 Ariadne Conill <ariadne@dereferenced.org>
# Copyright (C) 2020 Maximilian Wilhelm <max@sdn.clinic>
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# This software is provided 'as is' and without any warranty, express or
# implied.  In no event shall the authors be liable for any damages arising
# from the use of this software.

all_ports_exist() {
	local i=
	for i in "$@"; do
		[ -d /sys/class/net/$i ] || return 1
	done
	return 0
}

wait_ports() {
	local timeout= waitports=
	[ -z "$IF_BRIDGE_WAITPORT" ] && return 0
	set -- $IF_BRIDGE_WAITPORT
	timeout="$1"
	shift
	waitports="$@"
	[ -z "$waitports" ] && waitports="$PORTS"
	while ! all_ports_exist $waitports; do
		[ "$timeout" -eq 0 ] && return 0
		timeout=$(($timeout - 1))
		sleep 1
	done
}

all_ports() {
	local i=
	for i in /sys/class/net/*/ifindex; do
		i=${i%/*}
		i=${i##*/}
		case "$i" in
		lo|$IFACE) continue;;
		*) echo $i;;
		esac
	done
}

add_ports() {
	local port=
	for port in $PORTS; do
		if [ -x /etc/network/if-pre-up.d/vlan ]; then
			env IFACE=$port /etc/network/if-pre-up.d/vlan
		fi
		if [ -n "$IF_BRIDGE_HW" ]; then
			ip link set dev $port addr $IF_BRIDGE_HW
		fi
		brctl addif $IFACE $port && ip link set dev $port up
	done
}

del_ports() {
	local port=
	for port in $PORTS; do
		ip link set dev $port down
		brctl delif $IFACE $port
		if [ -x /etc/network/ip-post-down.d/vlan ]; then
			env IFACE=$port /etc/network/if-post-down.d/vlan
		fi
	done
}

set_bridge_opts() {
	[ -n "$IF_BRIDGE_AGEING" ] \
		&& brctl setageing $IFACE $IF_BRIDGE_AGEING
	[ -n "$IF_BRIDGE_BRIDGEPRIO" ] \
		&& brctl setbridgeprio $IFACE $IF_BRIDGE_BRIDGEPRIO
	[ -n "$IF_BRIDGE_FD" ] \
		&& brctl setfd $IFACE $IF_BRIDGE_FD
	[ -n "$IF_BRIDGE_GCINT" ] \
		&& brctl setgcint $IFACE $IF_BRIDGE_GCINT
	[ -n "$IF_BRIDGE_HELLO" ] \
		&& brctl sethello $IFACE $IF_BRIDGE_HELLO
	[ -n "$IF_BRIDGE_MAXAGE" ] \
		&& brctl setmaxage $IFACE $IF_BRIDGE_MAXAGE
	[ -n "$IF_BRIDGE_PATHCOST" ] \
		&& brctl setpathcost $IFACE $IF_BRIDGE_PATHCOST
	[ -n "$IF_BRIDGE_PORTPRIO" ] \
		&& brctl setportprio $IFACE $IF_BRIDGE_PORTPRIO
	[ -n "$IF_BRIDGE_STP" ] \
		&& brctl stp $IFACE $IF_BRIDGE_STP
}

all_ports_ready() {
	local port=
	for port in $PORTS; do
		case $(cat /sys/class/net/$IFACE/brif/$port/state) in
		""|0|3)	;; # 0 = disabled, 3 = forwarding
		[12]) 	return 1;;
		esac
	done
	return 0
}

find_maxwait() {
	awk '{printf("%.f\n", 2 * $0 / 100); }' \
		/sys/class/net/$IFACE/bridge/forward_delay
}

wait_bridge() {
	local timeout=$IF_BRIDGE_MAXWAIT
	if [ -z "$timeout" ]; then
		timeout=$(find_maxwait)
	fi
	ip link set dev $IFACE up
	while ! all_ports_ready; do
		[ $timeout -eq 0 ] && break
		timeout=$(($timeout - 1))
		sleep 1
	done
}

[ -z "$IF_BRIDGE_PORTS" ] && IF_BRIDGE_PORTS="$IF_REQUIRES"

case "$IF_BRIDGE_PORTS" in
"")	;;
none)	PORTS="";;
all)	PORTS=$(all_ports);;
*)	PORTS="$IF_BRIDGE_PORTS";;
esac

[ -z "$PORTS" ] && ! env | grep -q "^IF_BRIDGE" && exit

case "$PHASE" in
create)
	if [ ! -d "/sys/class/net/${IFACE}" ]; then
		brctl addbr "${IFACE}"
	fi
	;;
pre-up)
	wait_ports
	set_bridge_opts
	add_ports
	wait_bridge
	;;
post-down)
	del_ports
	ip link set dev $IFACE down
	;;
destroy)
	if [ -d "/sys/class/net/${IFACE}" ]; then
		brctl delbr "${IFACE}"
	fi
	;;
esac