#!/bin/sh

setglobal IFNAME = $1
setglobal CMD = $2

proc kill_daemon {
    setglobal NAME = $1
    setglobal PF = $2

    if test ! -r $PF {
	return
    }

    setglobal PID = $[cat $PF]
    if test $PID -gt 0 {
	if ps $PID | grep -q $NAME {
	    kill $PID
	}
    }
    rm $PF
}

if test $CMD = "P2P-GROUP-STARTED" {
    setglobal GIFNAME = $3
    if test $4 = "GO" {
	kill_daemon dhclient /var/run/dhclient-$GIFNAME.pid
	rm /var/run/dhclient.leases-$GIFNAME
	kill_daemon dnsmasq /var/run/dnsmasq.pid-$GIFNAME
	ifconfig $GIFNAME 192.168.42.1 up
	if ! dnsmasq -x /var/run/dnsmasq.pid-$GIFNAME \
	    -i $GIFNAME \
	    -F192.168.42.11,192.168.42.99 {
	    # another dnsmasq instance may be running and blocking us; try to
	    # start with -z to avoid that
	    dnsmasq -x /var/run/dnsmasq.pid-$GIFNAME \
		-i $GIFNAME \
		-F192.168.42.11,192.168.42.99 --listen-address 192.168.42.1 -z -p 0
	}
    }
    if test $4 = "client" {
	kill_daemon dhclient /var/run/dhclient-$GIFNAME.pid
	rm /var/run/dhclient.leases-$GIFNAME
	kill_daemon dnsmasq /var/run/dnsmasq.pid-$GIFNAME
	setglobal ipaddr = $[echo "$ifsjoin(ARGV)" | sed 's/.* ip_addr=\([^ ]*\).*/\1/]
	setglobal ipmask = $[echo "$ifsjoin(ARGV)" | sed 's/.* ip_mask=\([^ ]*\).*/\1/]
	setglobal goipaddr = $[echo "$ifsjoin(ARGV)" | sed 's/.* go_ip_addr=\([^ ]*\).*/\1/]
	if echo "$ipaddr$ipmask$goipaddr" | grep -q ' ' {
	    setglobal ipaddr = ''""
	    setglobal ipmask = ''""
	    setglobal goipaddr = ''""
	}
	if test -n $ipaddr {
	    sudo ifconfig $GIFNAME $ipaddr netmask $ipmask
	    sudo ip ro re default via $goipaddr
	    exit 0
	}
	dhclient -pf /var/run/dhclient-$GIFNAME.pid \
	    -lf /var/run/dhclient.leases-$GIFNAME \
	    -nw \
	    $GIFNAME
    }
}

if test $CMD = "P2P-GROUP-REMOVED" {
    setglobal GIFNAME = $3
    if test $4 = "GO" {
	kill_daemon dnsmasq /var/run/dnsmasq.pid-$GIFNAME
	ifconfig $GIFNAME 0.0.0.0
    }
    if test $4 = "client" {
	kill_daemon dhclient /var/run/dhclient-$GIFNAME.pid
	rm /var/run/dhclient.leases-$GIFNAME
	ifconfig $GIFNAME 0.0.0.0
    }
}

if test $CMD = "P2P-CROSS-CONNECT-ENABLE" {
    setglobal GIFNAME = $3
    setglobal UPLINK = $4
    # enable NAT/masquarade $GIFNAME -> $UPLINK
    iptables -P FORWARD DROP
    iptables -t nat -A POSTROUTING -o $UPLINK -j MASQUERADE
    iptables -A FORWARD -i $UPLINK -o $GIFNAME -m state --state RELATED,ESTABLISHED -j ACCEPT
    iptables -A FORWARD -i $GIFNAME -o $UPLINK -j ACCEPT
    sysctl net.ipv4.ip_forward=1
}

if test $CMD = "P2P-CROSS-CONNECT-DISABLE" {
    setglobal GIFNAME = $3
    setglobal UPLINK = $4
    # disable NAT/masquarade $GIFNAME -> $UPLINK
    sysctl net.ipv4.ip_forward=0
    iptables -t nat -D POSTROUTING -o $UPLINK -j MASQUERADE
    iptables -D FORWARD -i $UPLINK -o $GIFNAME -m state --state RELATED,ESTABLISHED -j ACCEPT
    iptables -D FORWARD -i $GIFNAME -o $UPLINK -j ACCEPT
}