[libvirt] [PATCH] network: don't add iptables rules for externally managed networks

[Laine Stump]

From: Laine Stump <laine at redhat.com>

This patch addresses https://bugzilla.redhat.com/show_bug.cgi?id=760442

When a network has any forward type other than route, nat or none, the
network configuration should be done completely external to libvirt -
libvirt only uses these types to allow configuring guests in a manner
that isn't tied to a specific host (all the host-specific information,
in particular interface names, port profile data, and bandwidth
configuration is in the network definition, and the guest
configuration only references it).

Due to a bug in the bridge network driver, libvirt was adding iptables
rules for networks with forward type='bridge' etc. any time libvirtd
was restarted while one of these networks was active.

This patch eliminates that error by only "reloading" iptables rules if
forward type is route, nat, or none.
---
 src/network/bridge_driver.c |   18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 63338a2..44c80e1 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1470,14 +1470,22 @@ networkReloadIptablesRules(struct network_driver *driver)
     VIR_INFO("Reloading iptables rules");
 
     for (i = 0 ; i < driver->networks.count ; i++) {
-        virNetworkObjLock(driver->networks.objs[i]);
-        if (virNetworkObjIsActive(driver->networks.objs[i])) {
-            networkRemoveIptablesRules(driver, driver->networks.objs[i]);
-            if (networkAddIptablesRules(driver, driver->networks.objs[i]) < 0) {
+        virNetworkObjPtr network = driver->networks.objs[i];
+
+        virNetworkObjLock(network);
+        if (virNetworkObjIsActive(network) &&
+            ((network->def->forwardType == VIR_NETWORK_FORWARD_NONE) ||
+             (network->def->forwardType == VIR_NETWORK_FORWARD_NAT) ||
+             (network->def->forwardType == VIR_NETWORK_FORWARD_ROUTE))) {
+            /* Only the three L3 network types that are configured by libvirt
+             * need to have iptables rules reloaded.
+             */
+            networkRemoveIptablesRules(driver, network);
+            if (networkAddIptablesRules(driver, network) < 0) {
                 /* failed to add but already logged */
             }
         }
-        virNetworkObjUnlock(driver->networks.objs[i]);
+        virNetworkObjUnlock(network);
     }
 }
 
-- 
1.7.7.3