util: log all setting of MAC addresses and vlan tags

Having this information available will make it easier to determine the
culprit when MAC or vlan tag appear to not be set, eg.:

  https://bugzilla.redhat.com/1364073

(This patch doesn't fix that bug, just makes it easier to diagnose)

src/util/virnetdev.c

@@ -241,6 +241,7 @@ virNetDevSetMACInternal(const char *ifname,
     int fd = -1;
     int ret = -1;
     struct ifreq ifr;
+    char macstr[VIR_MAC_STRING_BUFLEN];
 
     if ((fd = virNetDevSetupControl(ifname, &ifr)) < 0)
         return -1;
@@ -256,7 +257,6 @@ virNetDevSetMACInternal(const char *ifname,
     virMacAddrGetRaw(macaddr, (unsigned char *)ifr.ifr_hwaddr.sa_data);
 
     if (ioctl(fd, SIOCSIFHWADDR, &ifr) < 0) {
-        char macstr[VIR_MAC_STRING_BUFLEN];
 
         if (quiet && errno == EADDRNOTAVAIL)
             goto cleanup;
@@ -270,6 +270,10 @@ virNetDevSetMACInternal(const char *ifname,
     ret = 0;
 
  cleanup:
+    VIR_DEBUG("SIOCSIFHWADDR %s MAC=%s - %s",
+              ifname, virMacAddrFormat(macaddr, macstr),
+              ret < 0 ? "Fail" : "Success");
+
     VIR_FORCE_CLOSE(fd);
     return ret;
 }
@@ -312,6 +316,9 @@ virNetDevSetMACInternal(const char *ifname,
 
         ret = 0;
  cleanup:
+        VIR_DEBUG("SIOCSIFLLADDR %s MAC=%s - %s", ifname, mac + 1),
+                  ret < 0 ? "Fail" : "Success");
+
         VIR_FORCE_CLOSE(s);
 
         return ret;
@@ -1508,6 +1515,7 @@ virNetDevSetVfConfig(const char *ifname, int vf,
                      bool *allowRetry)
 {
     int rc = -1;
+    char macstr[VIR_MAC_STRING_BUFLEN];
     struct nlmsghdr *resp = NULL;
     struct nlmsgerr *err;
     unsigned int recvbuflen = 0;
@@ -1591,8 +1599,6 @@ virNetDevSetVfConfig(const char *ifname, int vf,
             goto cleanup;
         } else if (err->error) {
             /* other errors are permanent */
-            char macstr[VIR_MAC_STRING_BUFLEN];
-
             virReportSystemError(-err->error,
                                  _("Cannot set interface MAC/vlanid to %s/%d "
                                    "for ifname %s vf %d"),
@@ -1616,6 +1622,11 @@ virNetDevSetVfConfig(const char *ifname, int vf,
 
     rc = 0;
  cleanup:
+    VIR_DEBUG("RTM_SETLINK %s vf %d MAC=%s vlanid=%d - %s",
+              ifname, vf,
+              macaddr ? virMacAddrFormat(macaddr, macstr) : "(unchanged)",
+              vlanid, rc < 0 ? "Fail" : "Success");
+
     nlmsg_free(nl_msg);
     VIR_FREE(resp);
     return rc;