conf: Generate MAC address instead of keeping all zeroes

When we parse <mac address="00:00:00:00:00:00"/> we keep that in memory
and pass it down to the hypervisor. However, that MAC address is not
strictly valid as it is not marked as locally administered (bit 0x02)
but it is not even globally unique. It is also used for loopback device
on Linux, for example. And QEMU sees such MAC address just as "not
specified" and generates a new one that libvirt does not even know
about. So to make the overall experience better we now generate it if
the supplied one is all clear.

Resolves: https://issues.redhat.com/browse/RHEL-974

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index cac00c7f17fa9e5aae0d9aa11812d6f0621e609f..2c8727de54350504655dcca3ca546daf4c2ef2a3 100644 (file)
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -9665,7 +9665,7 @@ virDomainNetDefParseXML(virDomainXMLOption *xmlopt,
             return NULL;
     }
 
-    if (!macaddr) {
+    if (!macaddr || virMacAddrIsAllClear(&def->mac)) {
         virDomainNetGenerateMAC(xmlopt, &def->mac);
         def->mac_generated = true;
     }

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 1e3e407097e74e354a91c92c9eebea9ab6e14e2a..f8cda2f773eb2c0a73e8776cf40511f84c4b5140 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2743,6 +2743,7 @@ virMacAddrCompare;
 virMacAddrFormat;
 virMacAddrGenerate;
 virMacAddrGetRaw;
+virMacAddrIsAllClear;
 virMacAddrIsBroadcastRaw;
 virMacAddrIsMulticast;
 virMacAddrIsUnicast;

diff --git a/src/util/virmacaddr.c b/src/util/virmacaddr.c
index 073f298b5b66d71ea9a40eb79adda742ddd08851..e06bb200fc6842260a79cf90e97ab3bd76b907f1 100644 (file)
--- a/src/util/virmacaddr.c
+++ b/src/util/virmacaddr.c
@@ -246,6 +246,11 @@ virMacAddrIsBroadcastRaw(const unsigned char s[VIR_MAC_BUFLEN])
     return memcmp(virMacAddrBroadcastAddrRaw, s, sizeof(*s)) == 0;
 }
 
+bool virMacAddrIsAllClear(const virMacAddr *addr)
+{
+    return !virMacAddrCmpRaw(addr, (const unsigned char[VIR_MAC_BUFLEN]){0});
+}
+
 void
 virMacAddrFree(virMacAddr *addr)
 {

diff --git a/src/util/virmacaddr.h b/src/util/virmacaddr.h
index f32b58805a6196b82f3b3e6d20409c0d23fad7d9..7b9eb7443bd1f39919e50dd81a83f199069d2d5a 100644 (file)
--- a/src/util/virmacaddr.h
+++ b/src/util/virmacaddr.h
@@ -58,6 +58,7 @@ int virMacAddrParseHex(const char* str,
 bool virMacAddrIsUnicast(const virMacAddr *addr);
 bool virMacAddrIsMulticast(const virMacAddr *addr);
 bool virMacAddrIsBroadcastRaw(const unsigned char s[VIR_MAC_BUFLEN]);
+bool virMacAddrIsAllClear(const virMacAddr *addr);
 void virMacAddrFree(virMacAddr *addr);
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(virMacAddr, virMacAddrFree);

diff --git a/tests/genericxml2xmlindata/network-interface-mac-clear.xml b/tests/genericxml2xmlindata/network-interface-mac-clear.xml
new file mode 100644 (file)
index 0000000..41beda8
--- /dev/null
+++ b/tests/genericxml2xmlindata/network-interface-mac-clear.xml
@@ -0,0 +1,21 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <interface type='bridge'>
+      <mac address='00:00:00:00:00:00'/>
+      <source bridge='br0'/>
+    </interface>
+  </devices>
+</domain>

diff --git a/tests/genericxml2xmloutdata/network-interface-mac-clear.xml b/tests/genericxml2xmloutdata/network-interface-mac-clear.xml
new file mode 100644 (file)
index 0000000..a7935fa
--- /dev/null
+++ b/tests/genericxml2xmloutdata/network-interface-mac-clear.xml
@@ -0,0 +1,21 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <interface type='bridge'>
+      <mac address='52:54:00:00:00:00'/>
+      <source bridge='br0'/>
+    </interface>
+  </devices>
+</domain>

diff --git a/tests/genericxml2xmltest.c b/tests/genericxml2xmltest.c
index ce8073e85a309797d743529c7232c61f59c781fd..3cf9bd8159fb81121120deae56e2ccefb71651ce 100644 (file)
--- a/tests/genericxml2xmltest.c
+++ b/tests/genericxml2xmltest.c
@@ -187,6 +187,7 @@ mymain(void)
     DO_TEST("cpu-cache-disable");
 
     DO_TEST("network-interface-mac-check");
+    DO_TEST_DIFFERENT("network-interface-mac-clear");
 
     DO_TEST_DIFFERENT("chardev-tcp");
     DO_TEST_FAIL_ACTIVE("chardev-tcp-missing-host");
@@ -257,4 +258,5 @@ mymain(void)
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }
 
-VIR_TEST_MAIN(mymain)
+VIR_TEST_MAIN_PRELOAD(mymain,
+                      VIR_TEST_MOCK("virrandom"))