Re: [PATCH] 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(a)redhat.com&gt; --- src/conf/domain_conf.c | 2 +- src/util/virmacaddr.c | 5 +++++ src/util/virmacaddr.h | 1 + .../network-interface-mac-clear.xml | 21 +++++++++++++++++++ .../network-interface-mac-clear.xml | 21 +++++++++++++++++++ tests/genericxml2xmltest.c | 4 +++- 6 files changed, 52 insertions(+), 2 deletions(-) create mode 100644 tests/genericxml2xmlindata/network-interface-mac-clear.xml create mode 100644 tests/genericxml2xmloutdata/network-interface-mac-clear.xml diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index bb4f1fdb948d..652bd09b21b8 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -9675,7 +9675,7 @@ virDomainNetDefParseXML(virDomainXMLOption *xmlopt, return NULL; } - if (!macaddr) { + if (!macaddr || virMacAddrIsAllClear(&def->mac)) { virDomainNetGenerateMAC(xmlopt, &def->mac); def->mac_generated = true; } diff --git a/src/util/virmacaddr.c b/src/util/virmacaddr.c index 073f298b5b66..e06bb200fc68 100644 --- 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 f32b58805a61..7b9eb7443bd1 100644 --- 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);