conf: add prefix in virDomainNetDefParseXML

And use the newly added caps->host.netprefix for free interface
names that match the autogenerated target names.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

src/conf/domain_conf.c

@@ -8434,6 +8434,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
                         xmlNodePtr node,
                         xmlXPathContextPtr ctxt,
                         virHashTablePtr bootHash,
+                        char *prefix,
                         unsigned int flags)
 {
     virDomainNetDefPtr def;
@@ -8600,7 +8601,8 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
                 ifname = virXMLPropString(cur, "dev");
                 if (ifname &&
                     (flags & VIR_DOMAIN_DEF_PARSE_INACTIVE) &&
-                    STRPREFIX(ifname, VIR_NET_GENERATED_PREFIX)) {
+                     (STRPREFIX(ifname, VIR_NET_GENERATED_PREFIX) ||
+                      (prefix && STRPREFIX(ifname, prefix)))) {
                     /* An auto-generated target name, blank it out */
                     VIR_FREE(ifname);
                 }
@@ -12556,6 +12558,7 @@ virDomainDeviceDefParse(const char *xmlStr,
     xmlNodePtr node;
     xmlXPathContextPtr ctxt = NULL;
     virDomainDeviceDefPtr dev = NULL;
+    char *netprefix;
 
     if (!(xml = virXMLParseStringCtxt(xmlStr, _("(device_definition)"), &ctxt)))
         goto error;
@@ -12598,8 +12601,9 @@ virDomainDeviceDefParse(const char *xmlStr,
             goto error;
         break;
     case VIR_DOMAIN_DEVICE_NET:
+        netprefix = caps->host.netprefix;
         if (!(dev->data.net = virDomainNetDefParseXML(xmlopt, node, ctxt,
-                                                      NULL, flags)))
+                                                      NULL, netprefix, flags)))
             goto error;
         break;
     case VIR_DOMAIN_DEVICE_INPUT:
@@ -14747,6 +14751,7 @@ virDomainDefParseXML(xmlDocPtr xml,
     bool usb_other = false;
     bool usb_master = false;
     bool primaryVideo = false;
+    char *netprefix = NULL;
 
     if (flags & VIR_DOMAIN_DEF_PARSE_VALIDATE) {
         char *schema = virFileFindResource("domain.rng",
@@ -15932,11 +15937,13 @@ virDomainDefParseXML(xmlDocPtr xml,
         goto error;
     if (n && VIR_ALLOC_N(def->nets, n) < 0)
         goto error;
+    netprefix = caps->host.netprefix;
     for (i = 0; i < n; i++) {
         virDomainNetDefPtr net = virDomainNetDefParseXML(xmlopt,
                                                          nodes[i],
                                                          ctxt,
                                                          bootHash,
+                                                         netprefix,
                                                          flags);
         if (!net)
             goto error;