[libvirt] [PATCH RFC 3/7] libxl: implement virDomainInterfaceStats

[Jim Fehlig]

Joao Martins wrote:
> Introduce support for domainInterfaceStats API call for querying
> network interface statistics. Consequently it also enables the
> use of `virsh domifstat <dom> <interface name>` command.
>
> For getting statistics we resort to virNetInterfaceStats and let
> libvirt handle the platform specific nits. Note that the latter
> is not yet supported in FreeBSD.
>
> Signed-off-by: Joao Martins <joao.m.martins at oracle.com>
> ---
>  src/libxl/libxl_driver.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
>
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index 43e9e47..dc83083 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
> @@ -58,6 +58,7 @@
>  #include "virhostdev.h"
>  #include "network/bridge_driver.h"
>  #include "locking/domain_lock.h"
> +#include "virstats.h"
>  
>  #define VIR_FROM_THIS VIR_FROM_LIBXL
>  
> @@ -4640,6 +4641,57 @@ libxlDomainIsUpdated(virDomainPtr dom)
>  }
>  
>  static int
> +libxlDomainInterfaceStats(virDomainPtr dom,
> +                          const char *path,
> +                          virDomainInterfaceStatsPtr stats)
> +{
> +    libxlDriverPrivatePtr driver = dom->conn->privateData;
> +    virDomainObjPtr vm;
> +    int ret = -1;
> +    int domid, devid;
> +
> +    if (!(vm = libxlDomObjFromDomain(dom)))
> +        goto cleanup;
> +
> +    if (virDomainInterfaceStatsEnsureACL(dom->conn, vm->def) < 0)
> +        goto cleanup;
> +
> +    if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_QUERY) < 0)
> +        goto cleanup;
> +
> +    if (!virDomainObjIsActive(vm)) {
> +        virReportError(VIR_ERR_OPERATION_INVALID,
> +                       "%s", _("domain is not running"));
> +        goto endjob;
> +    }
> +
> +    if (sscanf(path, "vif%d.%d", &domid, &devid) != 2) {
> +            virReportError(VIR_ERR_INVALID_ARG, "%s",
> +                           _("invalid path, unknown device"));
> +            goto endjob;
> +    }
> +
> +    if (domid != vm->def->id) {
> +            virReportError(VIR_ERR_INVALID_ARG, "%s",
> +                           _("invalid path, domid doesn't match"));
> +            goto endjob;
> +    }
>   

Should we also ensure the domain has an interface matching devid before
calling virNetInterfaceStats()? I see the qemu driver has such a check,
but virNetInterfaceStats() also reports "Interface not found".

Regards,
Jim

> +
> +    ret = virNetInterfaceStats(path, stats);
> +
> + endjob:
> +    if (!libxlDomainObjEndJob(driver, vm)) {
> +        virObjectUnlock(vm);
> +        vm = NULL;
> +    }
> +
> + cleanup:
> +    if (vm)
> +        virObjectUnlock(vm);
> +    return ret;
> +}
> +
> +static int
>  libxlDomainGetTotalCPUStats(libxlDriverPrivatePtr driver,
>                              virDomainObjPtr vm,
>                              virTypedParameterPtr params,
> @@ -5407,6 +5459,7 @@ static virHypervisorDriver libxlHypervisorDriver = {
>  #endif
>      .nodeGetFreeMemory = libxlNodeGetFreeMemory, /* 0.9.0 */
>      .nodeGetCellsFreeMemory = libxlNodeGetCellsFreeMemory, /* 1.1.1 */
> +    .domainInterfaceStats = libxlDomainInterfaceStats, /* 1.2.20 */
>      .domainMemoryStats = libxlDomainMemoryStats, /* 1.2.20 */
>      .domainGetCPUStats = libxlDomainGetCPUStats, /* 1.2.20 */
>      .connectDomainEventRegister = libxlConnectDomainEventRegister, /* 0.9.0 */
>