From 48aaabd99df66e544acd0fda27fc8ee1dd56f48a Mon Sep 17 00:00:00 2001
From: Laine Stump <laine@laine.org>
Date: Mon, 3 Dec 2012 12:24:46 -0500
Subject: [PATCH] conf: fix virDomainNetGetActualDirect*() and BridgeName()

This resolves:

   https://bugzilla.redhat.com/show_bug.cgi?id=881480

These three functions:

  virDomainNetGetActualBridgeName
  virDomainNetGetActualDirectDev
  virDomainNetGetActualDirectMode

return attributes that are in a union whose contents are interpreted
differently depending on the actual->type and so they should only
return non-0 when actual->type is 'bridge' (in the first case) or
'direct' (in the other two cases, but I had neglected to do that, so
...DirectDev() was returning bridge.brname (which happens to share the
same spot in the union with direct.linkdev) if actual->type was
'bridge', and ...BridgeName was returning direct.linkdev when
actual->type was 'direct'.

How does this involve Bug 881480 (which was about the inability to
switch between two networks that both have "<forward mode='bridge'/>
<bridge name='xxx'/>"? Whenever the return value of
virDomainNetGetActualDirectDev() for the new and old network
definitions doesn't match, qemuDomainChangeNet() requires a "complete
reconnect" of the device, which qemu currently doesn't
support. ...DirectDev() *should* have been returning NULL for old and
new, but was instead returning the old and new bridge names, which
differ.

(The other two functions weren't causing any behavioral problems in
virDomainChangeNet(), but their problem and fix was identical, so I
included them in this same patch).
(cherry picked from commit 3738cf41f1012eca419e8fa0fa0575cb1e0552e3)
---
 src/conf/domain_conf.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index f7f9cbce77..96726f0fc4 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -14814,11 +14814,12 @@ virDomainNetGetActualBridgeName(virDomainNetDefPtr iface)
 {
     if (iface->type == VIR_DOMAIN_NET_TYPE_BRIDGE)
         return iface->data.bridge.brname;
-    if (iface->type != VIR_DOMAIN_NET_TYPE_NETWORK)
-        return NULL;
-    if (!iface->data.network.actual)
-        return NULL;
-    return iface->data.network.actual->data.bridge.brname;
+    if (iface->type == VIR_DOMAIN_NET_TYPE_NETWORK &&
+        iface->data.network.actual &&
+        iface->data.network.actual->type == VIR_DOMAIN_NET_TYPE_BRIDGE) {
+        return iface->data.network.actual->data.bridge.brname;
+    }
+    return NULL;
 }
 
 const char *
@@ -14826,11 +14827,12 @@ virDomainNetGetActualDirectDev(virDomainNetDefPtr iface)
 {
     if (iface->type == VIR_DOMAIN_NET_TYPE_DIRECT)
         return iface->data.direct.linkdev;
-    if (iface->type != VIR_DOMAIN_NET_TYPE_NETWORK)
-        return NULL;
-    if (!iface->data.network.actual)
-        return NULL;
-    return iface->data.network.actual->data.direct.linkdev;
+    if (iface->type == VIR_DOMAIN_NET_TYPE_NETWORK &&
+        iface->data.network.actual &&
+        iface->data.network.actual->type == VIR_DOMAIN_NET_TYPE_DIRECT) {
+        return iface->data.network.actual->data.direct.linkdev;
+    }
+    return NULL;
 }
 
 int
@@ -14838,11 +14840,12 @@ virDomainNetGetActualDirectMode(virDomainNetDefPtr iface)
 {
     if (iface->type == VIR_DOMAIN_NET_TYPE_DIRECT)
         return iface->data.direct.mode;
-    if (iface->type != VIR_DOMAIN_NET_TYPE_NETWORK)
-        return 0;
-    if (!iface->data.network.actual)
-        return 0;
-    return iface->data.network.actual->data.direct.mode;
+    if (iface->type == VIR_DOMAIN_NET_TYPE_NETWORK &&
+        iface->data.network.actual &&
+        iface->data.network.actual->type == VIR_DOMAIN_NET_TYPE_DIRECT) {
+        return iface->data.network.actual->data.direct.mode;
+    }
+    return 0;
 }
 
 virDomainHostdevDefPtr