[Xen-devel] [PATCH v3 3/8] libxl: implement virDomainInterfaceStats

[Joao Martins <joao.m.martins@xxxxxxxxxx>]

Introduce support for domainInterfaceStats API call for querying
network interface statistics. Consequently it also enables the
use of `virsh domifstat <dom> <interface name>` command.

After succesful guest creation we fill the network
interfaces names based on domain, device id and append suffix
if it's emulated in the following form: vif<domid>.<devid>[-emu]. Because
we need the devid from domain config (which is filled by libxl on domain
create)  we cannot do generate the names in console callback. On domain
cleanup we also clear ifname, in case it was set by libvirt (i.e.
being prefixed with "vif"). We also skip these two steps in case the name
of the interface was manually inserted by the adminstrator.

For getting the interface 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@xxxxxxxxxx>
---
Changes since v2:
 - Clear ifname if it's autogenerated, since otherwise will persist
 on successive domain starts. Change commit message reflecting this
 change.

Changes since v1:
 - Fill <virDomainNetDef>.ifname after domain start with generated
 name from libxl  based on domain id and devid returned by libxl.
 After that path validation don interfaceStats is enterily based
 on ifname pretty much like the other drivers.
 - Modify commit message reflecting the changes mentioned in
 the previous item.
 - Bump version to 1.2.22
---
 src/libxl/libxl_domain.c | 26 ++++++++++++++++++++++++++
 src/libxl/libxl_driver.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 40dcea1..adb4563 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -728,6 +728,17 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
         }
     }
 
+    if ((vm->def->nnets)) {
+        ssize_t i;
+
+        for (i = 0; i < vm->def->nnets; i++) {
+            virDomainNetDefPtr net = vm->def->nets[i];
+
+            if (STRPREFIX(net->ifname, "vif"))
+                VIR_FREE(net->ifname);
+        }
+    }
+
     if (virAsprintf(&file, "%s/%s.xml", cfg->stateDir, vm->def->name) > 0) {
         if (unlink(file) < 0 && errno != ENOENT && errno != ENOTDIR)
             VIR_DEBUG("Failed to remove domain XML for %s", vm->def->name);
@@ -901,6 +912,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, 
virDomainObjPtr vm,
     virDomainDefPtr def = NULL;
     virObjectEventPtr event = NULL;
     libxlSavefileHeader hdr;
+    ssize_t i;
     int ret = -1;
     uint32_t domid = 0;
     char *dom_xml = NULL;
@@ -1023,6 +1035,20 @@ libxlDomainStart(libxlDriverPrivatePtr driver, 
virDomainObjPtr vm,
      */
     vm->def->id = domid;
 
+    for (i = 0; i < vm->def->nnets; i++) {
+        virDomainNetDefPtr net = vm->def->nets[i];
+        libxl_device_nic *x_nic = &d_config.nics[i];
+        const char *suffix =
+            x_nic->nictype != LIBXL_NIC_TYPE_VIF ? "-emu" : "";
+
+        if (net->ifname)
+            continue;
+
+        if (virAsprintf(&net->ifname, "vif%d.%d%s",
+                        domid, x_nic->devid, suffix) < 0)
+            continue;
+    }
+
     /* Always enable domain death events */
     if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW))
         goto cleanup_dom;
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index f4fc7bc..9a5a74c 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
 
@@ -4643,6 +4644,52 @@ libxlDomainIsUpdated(virDomainPtr dom)
 }
 
 static int
+libxlDomainInterfaceStats(virDomainPtr dom,
+                          const char *path,
+                          virDomainInterfaceStatsPtr stats)
+{
+    libxlDriverPrivatePtr driver = dom->conn->privateData;
+    virDomainObjPtr vm;
+    ssize_t i;
+    int ret = -1;
+
+    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;
+    }
+
+    /* Check the path is one of the domain's network interfaces. */
+    for (i = 0; i < vm->def->nnets; i++) {
+        if (vm->def->nets[i]->ifname &&
+            STREQ(vm->def->nets[i]->ifname, path)) {
+            ret = virNetInterfaceStats(path, stats);
+            break;
+        }
+    }
+
+ 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,
@@ -5411,6 +5458,7 @@ static virHypervisorDriver libxlHypervisorDriver = {
 #endif
     .nodeGetFreeMemory = libxlNodeGetFreeMemory, /* 0.9.0 */
     .nodeGetCellsFreeMemory = libxlNodeGetCellsFreeMemory, /* 1.1.1 */
+    .domainInterfaceStats = libxlDomainInterfaceStats, /* 1.2.22 */
     .domainMemoryStats = libxlDomainMemoryStats, /* 1.2.22 */
     .domainGetCPUStats = libxlDomainGetCPUStats, /* 1.2.22 */
     .connectDomainEventRegister = libxlConnectDomainEventRegister, /* 0.9.0 */
-- 
2.1.4


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