Merge lp:~vishvananda/nova/dnsmasq-accept-rules-ms into lp:~hudson-openstack/nova/milestone-proposed

[Vish Ishaya]

Add iptables filter rules for dnsmasq (lp:844935)

On Fedora, the default policy for the INPUT chain in the filter table
is DROP. This means that DHCP and DNS request packets from the guest
get dropped.

Add these rules to allow the traffic through:

 $> sudo iptables -t filter -A nova-network-INPUT -i br0 -p udp -m udp --dport 67 -j ACCEPT
 $> sudo iptables -t filter -A nova-network-INPUT -i br0 -p tcp -m tcp --dport 67 -j ACCEPT
 $> sudo iptables -t filter -A nova-network-INPUT -i br0 -p udp -m udp --dport 53 -j ACCEPT
 $> sudo iptables -t filter -A nova-network-INPUT -i br0 -p tcp -m tcp --dport 53 -j ACCEPT

=== modified file 'nova/network/linux_net.py'
--- nova/network/linux_net.py	2011-09-19 22:05:27 +0000
+++ nova/network/linux_net.py	2011-09-20 09:59:25 +0000
@@ -554,6 +554,18 @@
     utils.execute('dhcp_release', dev, address, mac_address, run_as_root=True)
 
 
+def _add_dnsmasq_accept_rules(dev):
+    """Allow DHCP and DNS traffic through to dnsmasq."""
+    table = iptables_manager.ipv4['filter']
+    for port in [67, 53]:
+        for proto in ['udp', 'tcp']:
+            args = {'dev': dev, 'port': port, 'proto': proto}
+            table.add_rule('INPUT',
+                           '-i %(dev)s -p %(proto)s -m %(proto)s '
+                           '--dport %(port)s -j ACCEPT' % args)
+    iptables_manager.apply()
+
+
 # NOTE(ja): Sending a HUP only reloads the hostfile, so any
 #           configuration options (like dchp-range, vlan, ...)
 #           aren't reloaded.
@@ -616,6 +628,8 @@
 
     _execute(*cmd, run_as_root=True)
 
+    _add_dnsmasq_accept_rules(dev)
+
 
 @utils.synchronized('radvd_start')
 def update_ra(context, dev, network_ref):
@@ -824,7 +838,6 @@
         raise NotImplementedError()
 
 
-
 # plugs interfaces using Linux Bridge
 class LinuxBridgeInterfaceDriver(LinuxNetInterfaceDriver):