[PATCH 07/10] libxl: prevent attaching multiple netdevs with the same MAC

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

It will not be possible to detach such device later. Also improve
logging in such cases.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
---
 src/libxl/libxl_driver.c | 41 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index ce3a99b..005cc96 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -2787,6 +2787,7 @@ libxlDomainAttachNetDevice(libxlDriverPrivatePtr driver,
     int actualType;
     libxl_device_nic nic;
     int ret = -1;
+    char mac[VIR_MAC_STRING_BUFLEN];
 
     /* preallocate new slot for device */
     if (VIR_REALLOC_N(vm->def->nets, vm->def->nnets + 1) < 0)
@@ -2801,6 +2802,14 @@ libxlDomainAttachNetDevice(libxlDriverPrivatePtr driver,
 
     actualType = virDomainNetGetActualType(net);
 
+    /* -2 means "multiple matches" so then fail also */
+    if (virDomainNetFindIdx(vm->def, net) != -1) {
+        virReportError(VIR_ERR_OPERATION_FAILED,
+                _("device matching mac address %s already exists"),
+                virMacAddrFormat(&net->mac, mac));
+        return -1;
+    }
+
     if (actualType == VIR_DOMAIN_NET_TYPE_HOSTDEV) {
         /* This is really a "smart hostdev", so it should be attached
          * as a hostdev (the hostdev code will reach over into the
@@ -2879,6 +2888,7 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev)
     virDomainHostdevDefPtr hostdev;
     virDomainHostdevDefPtr found;
     virDomainHostdevSubsysPCIPtr pcisrc;
+    char mac[VIR_MAC_STRING_BUFLEN];
 
     switch (dev->type) {
         case VIR_DOMAIN_DEVICE_DISK:
@@ -2896,6 +2906,12 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev)
 
         case VIR_DOMAIN_DEVICE_NET:
             net = dev->data.net;
+            if (virDomainNetFindIdx(vmdef, net) >= 0) {
+                virReportError(VIR_ERR_INVALID_ARG,
+                               _("network device with mac %s already exists."),
+                               virMacAddrFormat(&net->mac, mac));
+                return -1;
+            }
             if (virDomainNetInsert(vmdef, net))
                 return -1;
             dev->data.net = NULL;
@@ -3060,8 +3076,18 @@ libxlDomainDetachNetDevice(libxlDriverPrivatePtr driver,
     char mac[VIR_MAC_STRING_BUFLEN];
     int ret = -1;
 
-    if ((detachidx = virDomainNetFindIdx(vm->def, net)) < 0)
+    if ((detachidx = virDomainNetFindIdx(vm->def, net)) < 0) {
+        if (detachidx == -2) {
+            virReportError(VIR_ERR_OPERATION_FAILED,
+                    _("multiple devices matching mac address %s found"),
+                    virMacAddrFormat(&net->mac, mac));
+        } else {
+            virReportError(VIR_ERR_OPERATION_FAILED,
+                    _("network device %s not found"),
+                    virMacAddrFormat(&net->mac, mac));
+        }
         return -1;
+    }
 
     detach = vm->def->nets[detachidx];
 
@@ -3136,6 +3162,7 @@ libxlDomainDetachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev)
     virDomainHostdevDefPtr hostdev, det_hostdev;
     virDomainNetDefPtr net;
     int idx;
+    char mac[VIR_MAC_STRING_BUFLEN];
 
     switch (dev->type) {
         case VIR_DOMAIN_DEVICE_DISK:
@@ -3150,8 +3177,18 @@ libxlDomainDetachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev)
 
         case VIR_DOMAIN_DEVICE_NET:
             net = dev->data.net;
-            if ((idx = virDomainNetFindIdx(vmdef, net)) < 0)
+            if ((idx = virDomainNetFindIdx(vmdef, net)) < 0) {
+                if (idx == -2) {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                            _("multiple devices matching mac address %s found"),
+                            virMacAddrFormat(&dev->data.net->mac, mac));
+                } else {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                            _("network device %s not found"),
+                            virMacAddrFormat(&dev->data.net->mac, mac));
+                }
                 return -1;
+            }
 
             /* this is guaranteed to succeed */
             virDomainNetDefFree(virDomainNetRemove(vmdef, idx));
-- 
1.8.3.1

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