interface: Fix udev backend bridge device display

The bridge device was showing the vnet devices created for the domains
as connected to the bridge. libvirt should only show host devices when
trying to get the interface definition rather than the domain devices as
well.

src/interface/interface_backend_udev.c

@@ -24,7 +24,9 @@
 #include <libudev.h>
 
 #include "virerror.h"
+#include "c-ctype.h"
 #include "datatypes.h"
+#include "domain_conf.h"
 #include "interface_driver.h"
 #include "interface_conf.h"
 #include "viralloc.h"
@@ -527,6 +529,16 @@ udevIfaceBridgeScanDirFilter(const struct dirent *entry)
     if (STREQ(entry->d_name, ".") || STREQ(entry->d_name, ".."))
         return 0;
 
+    /* Omit the domain interfaces from the list of bridge attached
+     * devices. All we can do is check for the device name matching
+     * vnet%d. Improvements to this check are welcome.
+     */
+    if (strlen(entry->d_name) >= 5) {
+        if (STRPREFIX(entry->d_name, VIR_NET_GENERATED_PREFIX) &&
+            c_isdigit(entry->d_name[4]))
+            return 0;
+    }
+
     return 1;
 }