virNetDevTapInterfaceStats: Allow caller to not swap the statistics

https://bugzilla.redhat.com/show_bug.cgi?id=1497410

The comment in virNetDevTapInterfaceStats() implementation for
Linux states that packets transmitted by domain are received by
the host and vice versa. Well, this is true but not for all types
of interfaces. For instance, for macvtaps when TAP device is
hooked right onto a physical device any packet that domain sends
looks also like a packet sent to the host. Therefore, we should
allow caller to chose if the stats returned should be straight
copy or swapped.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This commit is contained in:
Michal Privoznik 2017-10-02 13:36:56 +02:00
parent c2c47b586f
commit d86fd2402e
9 changed files with 122 additions and 46 deletions

View File

@ -26781,7 +26781,7 @@ virDomainStateReasonFromString(virDomainState state, const char *reason)
*/
virDomainNetType
virDomainNetGetActualType(virDomainNetDefPtr iface)
virDomainNetGetActualType(const virDomainNetDef *iface)
{
if (iface->type != VIR_DOMAIN_NET_TYPE_NETWORK)
return iface->type;

View File

@ -3022,7 +3022,7 @@ int virDomainGraphicsListenAppendSocket(virDomainGraphicsDefPtr def,
const char *socket)
ATTRIBUTE_NONNULL(1);
virDomainNetType virDomainNetGetActualType(virDomainNetDefPtr iface);
virDomainNetType virDomainNetGetActualType(const virDomainNetDef *iface);
const char *virDomainNetGetActualBridgeName(virDomainNetDefPtr iface);
int virDomainNetGetActualBridgeMACTableManager(virDomainNetDefPtr iface);
const char *virDomainNetGetActualDirectDev(virDomainNetDefPtr iface);
@ -3394,4 +3394,39 @@ virDomainGenerateMachineName(const char *drivername,
int id,
const char *name,
bool privileged);
/**
* virDomainNetTypeSharesHostView:
* @net: interface
*
* Some types of interfaces "share" the host view. For instance,
* for macvtap interface, every domain RX is the host RX too. And
* every domain TX is host TX too. IOW, for some types of
* interfaces guest and host are on the same side of RX/TX
* barrier. This is important so that we set up QoS correctly and
* report proper stats.
*/
static inline bool
virDomainNetTypeSharesHostView(const virDomainNetDef *net)
{
virDomainNetType actualType = virDomainNetGetActualType(net);
switch (actualType) {
case VIR_DOMAIN_NET_TYPE_DIRECT:
case VIR_DOMAIN_NET_TYPE_ETHERNET:
return true;
case VIR_DOMAIN_NET_TYPE_USER:
case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
case VIR_DOMAIN_NET_TYPE_SERVER:
case VIR_DOMAIN_NET_TYPE_CLIENT:
case VIR_DOMAIN_NET_TYPE_MCAST:
case VIR_DOMAIN_NET_TYPE_NETWORK:
case VIR_DOMAIN_NET_TYPE_BRIDGE:
case VIR_DOMAIN_NET_TYPE_INTERNAL:
case VIR_DOMAIN_NET_TYPE_HOSTDEV:
case VIR_DOMAIN_NET_TYPE_UDP:
case VIR_DOMAIN_NET_TYPE_LAST:
break;
}
return false;
}
#endif /* __DOMAIN_CONF_H */

View File

@ -4985,7 +4985,8 @@ libxlDomainInterfaceStats(virDomainPtr dom,
goto endjob;
}
if (virNetDevTapInterfaceStats(path, stats) < 0)
if (virNetDevTapInterfaceStats(path, stats,
!virDomainNetTypeSharesHostView(net)) < 0)
goto endjob;
ret = 0;

View File

@ -2878,7 +2878,8 @@ lxcDomainInterfaceStats(virDomainPtr dom,
goto endjob;
}
if (virNetDevTapInterfaceStats(path, stats) < 0)
if (virNetDevTapInterfaceStats(path, stats,
!virDomainNetTypeSharesHostView(net)) < 0)
goto endjob;
ret = 0;

View File

@ -2012,7 +2012,8 @@ openvzDomainInterfaceStats(virDomainPtr dom,
goto cleanup;
}
if (virNetDevTapInterfaceStats(path, stats) < 0)
if (virNetDevTapInterfaceStats(path, stats,
!virDomainNetTypeSharesHostView(net)) < 0)
goto cleanup;
ret = 0;

View File

@ -11040,7 +11040,8 @@ qemuDomainInterfaceStats(virDomainPtr dom,
if (virNetDevOpenvswitchInterfaceStats(path, stats) < 0)
goto cleanup;
} else {
if (virNetDevTapInterfaceStats(path, stats) < 0)
if (virNetDevTapInterfaceStats(path, stats,
!virDomainNetTypeSharesHostView(net)) < 0)
goto cleanup;
}
@ -19559,26 +19560,27 @@ qemuDomainGetStatsInterface(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
/* Check the path is one of the domain's network interfaces. */
for (i = 0; i < dom->def->nnets; i++) {
virDomainNetDefPtr net = dom->def->nets[i];
virDomainNetType actualType;
if (!dom->def->nets[i]->ifname)
if (!net->ifname)
continue;
memset(&tmp, 0, sizeof(tmp));
actualType = virDomainNetGetActualType(dom->def->nets[i]);
actualType = virDomainNetGetActualType(net);
QEMU_ADD_NAME_PARAM(record, maxparams,
"net", "name", i, dom->def->nets[i]->ifname);
"net", "name", i, net->ifname);
if (actualType == VIR_DOMAIN_NET_TYPE_VHOSTUSER) {
if (virNetDevOpenvswitchInterfaceStats(dom->def->nets[i]->ifname,
&tmp) < 0) {
if (virNetDevOpenvswitchInterfaceStats(net->ifname, &tmp) < 0) {
virResetLastError();
continue;
}
} else {
if (virNetDevTapInterfaceStats(dom->def->nets[i]->ifname, &tmp) < 0) {
if (virNetDevTapInterfaceStats(net->ifname, &tmp,
!virDomainNetTypeSharesHostView(net)) < 0) {
virResetLastError();
continue;
}

View File

@ -676,14 +676,27 @@ int virNetDevTapCreateInBridgePort(const char *brname,
}
/*-------------------- interface stats --------------------*/
/* Just reads the named interface, so not Xen or QEMU-specific.
* NB. Caller must check that libvirt user is trying to query
* the interface of a domain they own. We do no such checking.
/**
* virNetDevTapInterfaceStats:
* @ifname: interface
* @stats: where to store statistics
* @swapped: whether to swap RX/TX fields
*
* Fetch RX/TX statistics for given named interface (@ifname) and
* store them at @stats. The returned statistics are always from
* domain POV. Because in some cases this means swapping RX/TX in
* the stats and in others this means no swapping (consider TAP
* vs macvtap) caller might choose if the returned stats should
* be @swapped or not.
*
* Returns 0 on success, -1 otherwise (with error reported).
*/
#ifdef __linux__
int
virNetDevTapInterfaceStats(const char *ifname,
virDomainInterfaceStatsPtr stats)
virDomainInterfaceStatsPtr stats,
bool swapped)
{
int ifname_len;
FILE *fp;
@ -718,30 +731,35 @@ virNetDevTapInterfaceStats(const char *ifname,
*colon = '\0';
if (colon-ifname_len >= line &&
STREQ(colon-ifname_len, ifname)) {
/* IMPORTANT NOTE!
* /proc/net/dev vif<domid>.nn sees the network from the point
* of view of dom0 / hypervisor. So bytes TRANSMITTED by dom0
* are bytes RECEIVED by the domain. That's why the TX/RX fields
* appear to be swapped here.
*/
if (sscanf(colon+1,
"%lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld",
&tx_bytes, &tx_packets, &tx_errs, &tx_drop,
&dummy, &dummy, &dummy, &dummy,
&rx_bytes, &rx_packets, &rx_errs, &rx_drop,
&dummy, &dummy, &dummy, &dummy,
&tx_bytes, &tx_packets, &tx_errs, &tx_drop,
&dummy, &dummy, &dummy, &dummy) != 16)
continue;
stats->rx_bytes = rx_bytes;
stats->rx_packets = rx_packets;
stats->rx_errs = rx_errs;
stats->rx_drop = rx_drop;
stats->tx_bytes = tx_bytes;
stats->tx_packets = tx_packets;
stats->tx_errs = tx_errs;
stats->tx_drop = tx_drop;
VIR_FORCE_FCLOSE(fp);
if (swapped) {
stats->rx_bytes = tx_bytes;
stats->rx_packets = tx_packets;
stats->rx_errs = tx_errs;
stats->rx_drop = tx_drop;
stats->tx_bytes = rx_bytes;
stats->tx_packets = rx_packets;
stats->tx_errs = rx_errs;
stats->tx_drop = rx_drop;
} else {
stats->rx_bytes = rx_bytes;
stats->rx_packets = rx_packets;
stats->rx_errs = rx_errs;
stats->rx_drop = rx_drop;
stats->tx_bytes = tx_bytes;
stats->tx_packets = tx_packets;
stats->tx_errs = tx_errs;
stats->tx_drop = tx_drop;
}
VIR_FORCE_FCLOSE(fp);
return 0;
}
}
@ -754,7 +772,8 @@ virNetDevTapInterfaceStats(const char *ifname,
#elif defined(HAVE_GETIFADDRS) && defined(AF_LINK)
int
virNetDevTapInterfaceStats(const char *ifname,
virDomainInterfaceStatsPtr stats)
virDomainInterfaceStatsPtr stats,
bool swapped)
{
struct ifaddrs *ifap, *ifa;
struct if_data *ifd;
@ -775,18 +794,33 @@ virNetDevTapInterfaceStats(const char *ifname,
if (STREQ(ifa->ifa_name, ifname)) {
ifd = (struct if_data *)ifa->ifa_data;
stats->tx_bytes = ifd->ifi_ibytes;
stats->tx_packets = ifd->ifi_ipackets;
stats->tx_errs = ifd->ifi_ierrors;
stats->tx_drop = ifd->ifi_iqdrops;
stats->rx_bytes = ifd->ifi_obytes;
stats->rx_packets = ifd->ifi_opackets;
stats->rx_errs = ifd->ifi_oerrors;
if (swapped) {
stats->tx_bytes = ifd->ifi_ibytes;
stats->tx_packets = ifd->ifi_ipackets;
stats->tx_errs = ifd->ifi_ierrors;
stats->tx_drop = ifd->ifi_iqdrops;
stats->rx_bytes = ifd->ifi_obytes;
stats->rx_packets = ifd->ifi_opackets;
stats->rx_errs = ifd->ifi_oerrors;
# ifdef HAVE_STRUCT_IF_DATA_IFI_OQDROPS
stats->rx_drop = ifd->ifi_oqdrops;
stats->rx_drop = ifd->ifi_oqdrops;
# else
stats->rx_drop = 0;
stats->rx_drop = 0;
# endif
} else {
stats->tx_bytes = ifd->ifi_obytes;
stats->tx_packets = ifd->ifi_opackets;
stats->tx_errs = ifd->ifi_oerrors;
# ifdef HAVE_STRUCT_IF_DATA_IFI_OQDROPS
stats->tx_drop = ifd->ifi_oqdrops;
# else
stats->tx_drop = 0;
# endif
stats->rx_bytes = ifd->ifi_ibytes;
stats->rx_packets = ifd->ifi_ipackets;
stats->rx_errs = ifd->ifi_ierrors;
stats->rx_drop = ifd->ifi_iqdrops;
}
ret = 0;
break;
@ -803,7 +837,8 @@ virNetDevTapInterfaceStats(const char *ifname,
#else
int
virNetDevTapInterfaceStats(const char *ifname ATTRIBUTE_UNUSED,
virDomainInterfaceStatsPtr stats ATTRIBUTE_UNUSED)
virDomainInterfaceStatsPtr stats ATTRIBUTE_UNUSED,
bool swapped ATTRIBUTE_UNUSED)
{
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("interface stats not implemented on this platform"));

View File

@ -92,7 +92,8 @@ int virNetDevTapCreateInBridgePort(const char *brname,
ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NOINLINE;
int virNetDevTapInterfaceStats(const char *ifname,
virDomainInterfaceStatsPtr stats)
virDomainInterfaceStatsPtr stats,
bool swapped)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
#endif /* __VIR_NETDEV_TAP_H__ */

View File

@ -1468,7 +1468,7 @@ xenHypervisorDomainInterfaceStats(virDomainDefPtr def,
return -1;
}
return virNetDevTapInterfaceStats(path, stats);
return virNetDevTapInterfaceStats(path, stats, true);
#else
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("/proc/net/dev: Interface not found"));