network: include plugged interface XML in "plugged" network hook

The network hook script gets called whenever an interface is plugged
into or unplugged from a network, but even though the full XML of both
the network and the domain is included, there is no reasonable way to
determine what exact resources the plugged interface is using:

1) Prior to a recent patch which modified the status XML of interfaces
to include the information about actual hardware resources used, it
would be possible to scan through the domain XML output sent to the
hook, and from there find the correct interface, but that interface
definition would not include any runtime info (e.g. bandwidth or vlan
taken from a portgroup, or which physdev was used in case of a macvtap
network).

2) After the patch modifying the status XML of interfaces, the network
name would no longer be included in the domain XML, so it would be
completely impossible to determine which interface was the one being
plugged.

To solve that problem, this patch includes a single <interface>
element at the beginning of the XML sent to the network hook for
"plugged" and "unplugged" (just inside <hookData>) that is the status
XML of the interface being plugged. This XML will include all info
gathered from the chosen network and portgroup.

NB: due to hardcoded spaces in all of the device *Format() functions,
the <interface> element inside the <hookData> will be indented by 6
spaces rather than 2. I had intended to fix this, but it turns out
that to make virDomainNetDefFormat() indentation relative, I would
have to do the same to virDomainDeviceInfoFormat(), and that function
is called from 19 places - making that a prerequisite of this patch
would cause too many merge difficulties if we needed to backport
network hooks, so I chose to ignore the problem here and fix the
problem for *all* devices in a followup later.

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index a6c719df3e4afae97ffff5700f61cf109488a4a5..152bd06b03d0cef1eaaa0c3f3efd8e67fbd84dd7 100644 (file)
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -141,6 +141,7 @@ networkObjFromNetwork(virNetworkPtr net)
 static int
 networkRunHook(virNetworkObjPtr network,
                virDomainDefPtr dom,
+               virDomainNetDefPtr iface,
                int op,
                int sub_op)
 {
@@ -158,6 +159,8 @@ networkRunHook(virNetworkObjPtr network,
 
         virBufferAddLit(&buf, "<hookData>\n");
         virBufferAdjustIndent(&buf, 2);
+        if (iface && virDomainNetDefFormat(&buf, iface, 0) < 0)
+            goto cleanup;
         if (virNetworkDefFormatBuf(&buf, network->def, 0) < 0)
             goto cleanup;
         if (dom && virDomainDefFormatInternal(dom, 0, &buf) < 0)
@@ -2067,7 +2070,7 @@ networkStartNetwork(virNetworkDriverStatePtr driver,
 
     /* Run an early hook to set-up missing devices.
      * If the script raised an error abort the launch. */
-    if (networkRunHook(network, NULL,
+    if (networkRunHook(network, NULL, NULL,
                        VIR_HOOK_NETWORK_OP_START,
                        VIR_HOOK_SUBOP_BEGIN) < 0)
         goto cleanup;
@@ -2092,7 +2095,7 @@ networkStartNetwork(virNetworkDriverStatePtr driver,
     }
 
     /* finally we can call the 'started' hook script if any */
-    if (networkRunHook(network, NULL,
+    if (networkRunHook(network, NULL, NULL,
                        VIR_HOOK_NETWORK_OP_STARTED,
                        VIR_HOOK_SUBOP_BEGIN) < 0)
         goto cleanup;
@@ -2158,7 +2161,7 @@ static int networkShutdownNetwork(virNetworkDriverStatePtr driver,
     }
 
     /* now that we know it's stopped call the hook if present */
-    networkRunHook(network, NULL, VIR_HOOK_NETWORK_OP_STOPPED,
+    networkRunHook(network, NULL, NULL, VIR_HOOK_NETWORK_OP_STOPPED,
                    VIR_HOOK_SUBOP_END);
 
     network->active = 0;
@@ -3659,14 +3662,8 @@ validate:
         }
     }
 
-    /* finally we can call the 'plugged' hook script if any */
-    if (networkRunHook(network, dom,
-                       VIR_HOOK_NETWORK_OP_IFACE_PLUGGED,
-                       VIR_HOOK_SUBOP_BEGIN) < 0)
-        goto error;
-
     if (dev) {
-        /* we are now assured of success, so mark the allocation */
+        /* mark the allocation */
         dev->connections++;
         if (actualType != VIR_DOMAIN_NET_TYPE_HOSTDEV) {
             VIR_DEBUG("Using physical device %s, %d connections",
@@ -3684,6 +3681,19 @@ validate:
         VIR_DEBUG("Using network %s, %d connections",
                   netdef->name, netdef->connections);
     }
+
+    /* finally we can call the 'plugged' hook script if any */
+    if (networkRunHook(network, dom, iface,
+                       VIR_HOOK_NETWORK_OP_IFACE_PLUGGED,
+                       VIR_HOOK_SUBOP_BEGIN) < 0) {
+        /* adjust for failure */
+        if (dev)
+            dev->connections--;
+        if (netdef)
+            netdef->connections--;
+        goto error;
+    }
+
     ret = 0;
 
 cleanup:
@@ -3865,14 +3875,20 @@ networkNotifyActualDevice(virDomainDefPtr dom,
     }
 
 success:
-    /* finally we can call the 'plugged' hook script if any */
-    if (networkRunHook(network, dom, VIR_HOOK_NETWORK_OP_IFACE_PLUGGED,
-                       VIR_HOOK_SUBOP_BEGIN) < 0)
-        goto error;
-
     netdef->connections++;
     VIR_DEBUG("Using network %s, %d connections",
               netdef->name, netdef->connections);
+
+    /* finally we can call the 'plugged' hook script if any */
+    if (networkRunHook(network, dom, iface, VIR_HOOK_NETWORK_OP_IFACE_PLUGGED,
+                       VIR_HOOK_SUBOP_BEGIN) < 0) {
+        /* adjust for failure */
+        if (dev)
+            dev->connections--;
+        netdef->connections--;
+        goto error;
+    }
+
     ret = 0;
 cleanup:
     if (network)
@@ -4018,7 +4034,7 @@ success:
         netdef->connections--;
 
     /* finally we can call the 'unplugged' hook script if any */
-    networkRunHook(network, dom, VIR_HOOK_NETWORK_OP_IFACE_UNPLUGGED,
+    networkRunHook(network, dom, iface, VIR_HOOK_NETWORK_OP_IFACE_UNPLUGGED,
                    VIR_HOOK_SUBOP_BEGIN);
 
     VIR_DEBUG("Releasing network %s, %d connections",