#!/usr/bin/python
# VSYS script to ifdown per-slice virtual network interfaces from the root slice
#   Thom Haddow - 06/10/09
#
# Gets slice name as argv[1]
# Takes remaining args on stdin:
#   - Interface name (eg [tun|tap]<sliceid>-<n>)

import sys
import pwd
import os
import re


if len(sys.argv) != 2: sys.exit(1)

# VSYS scripts get slicename as $1
slicename=sys.argv[1]
sliceid = pwd.getpwnam(slicename).pw_uid


# Read interface name
vif = sys.stdin.readline().strip() # interface name


# Validate interface name
if len(vif)>16:
    print >>sys.stderr, "Interface name %s invalid"%(vif)
    sys.exit(1)

if re.match(r'(tun|tap)%d-\d+' % sliceid, vif ) is None:
    print >>sys.stderr, "Interface name %s does not match slice id %d."%(vif, sliceid)
    sys.exit(1)



# Remove iptables rules
public_src = os.popen("ifconfig | grep $(ip route | grep default | awk '{print $3}' | awk -F. '{print $1\"[.]\"$2}') | head -1 | awk '{print $2}' | awk -F : '{print $2}'").read().rstrip()
cmd_iptables_del_in = "/sbin/iptables -D INPUT -i %s -m mark -m state --state NEW ! --mark %d -j DROP 2>/dev/null" % (vif, sliceid)
cmd_iptables_del_out = "/sbin/iptables -D OUTPUT -o %s -m mark -m state --state NEW ! --mark %d -j DROP 2>/dev/null" % (vif, sliceid)
cmd_iptables_del_pr = "/sbin/iptables -t nat -D POSTROUTING -s $(ip ro | grep 'dev %s' | head -1 | awk '{print $1}') -j SNAT --to-source %s --random 2>/dev/null" % (vif, public_src,)
cmd_gre_del = "ip link del %s 2>/dev/null" % (vif,)
cmd_iptables_del_gre_pr = "/sbin/iptables -t mangle -D INPUT -i %s -m mark --mark 0 -j MARK --set-mark %s 2>/dev/null" % (vif, sliceid)

os.system(cmd_iptables_del_in)
os.system(cmd_iptables_del_out)
os.system(cmd_iptables_del_pr)
os.system(cmd_iptables_del_gre_pr)

# Bring interface down
cmd_ifconfig = "/sbin/ifconfig %s down" % (vif)
os.system(cmd_ifconfig)

# Delete GRE tunnel (if any)
os.system(cmd_gre_del)