This function retrieves the name of the OVS bridge that the given
netdev is attached to. This separate function is necessary because OVS
set the IFLA_MASTER attribute to "ovs-system" for all netdevs that are
attached to an OVS bridge, so the standard method of retrieving the
master can't be used.
Signed-off-by: Laine Stump <laine@laine.org>
---
src/libvirt_private.syms | 1 +
src/util/virnetdevopenvswitch.c | 55 +++++++++++++++++++++++++++++++++++++++++
src/util/virnetdevopenvswitch.h | 6 +++++
3 files changed, 62 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 98913a577a..386f53eeb9 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2364,6 +2364,7 @@ virNetDevMidonetUnbindPort;
virNetDevOpenvswitchAddPort;
virNetDevOpenvswitchGetMigrateData;
virNetDevOpenvswitchGetVhostuserIfname;
+virNetDevOpenvswitchInterfaceGetMaster;
virNetDevOpenvswitchInterfaceStats;
virNetDevOpenvswitchRemovePort;
virNetDevOpenvswitchSetMigrateData;
diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
index f86f698430..af3f2a773d 100644
--- a/src/util/virnetdevopenvswitch.c
+++ b/src/util/virnetdevopenvswitch.c
@@ -404,6 +404,61 @@ virNetDevOpenvswitchInterfaceStats(const char *ifname,
return ret;
}
+
+/**
+ * virNetDeOpenvswitchGetMaster:
+ * @ifname: name of interface we're interested in
+ * @master: used to return a string containing the name of @ifname's "master"
+ * (this is the bridge or bond device that this device is attached to)
+ *
+ * Returns 0 on success, -1 on failure (if @ifname has no master
+ * @master will be NULL, but return value will still be 0 (success)).
+ *
+ * NB: This function is needed because the IFLA_MASTER attribute of an
+ * interface in a netlink dump (see virNetDevGetMaster()) will always
+ * return "ovs-system" for any interface that is attached to an OVS
+ * switch. When that happens, virNetDevOpenvswitchInterfaceGetMaster()
+ * must be called to get the "real" master of the interface.
+ */
+int
+virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
+{
+ virCommandPtr cmd = NULL;
+ int ret = -1;
+ int exitstatus;
+
+ *master = NULL;
+ cmd = virCommandNew(OVSVSCTL);
+ virNetDevOpenvswitchAddTimeout(cmd);
+ virCommandAddArgList(cmd, "iface-to-br", ifname, NULL);
+ virCommandSetOutputBuffer(cmd, master);
+
+ if (virCommandRun(cmd, &exitstatus) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Unable to run command to get OVS master for "
+ "interface %s"), ifname);
+ goto cleanup;
+ }
+
+ /* non-0 exit code just means that the interface has no master in OVS */
+ if (exitstatus != 0)
+ VIR_FREE(*master);
+
+ if (*master) {
+ /* truncate at the first newline */
+ char *nl = strchr(*master, '\n');
+ if (nl)
+ *nl = '\0';
+ }
+
+ VIR_DEBUG("OVS master for %s is %s", ifname, *master ? *master : "(none)");
+
+ ret = 0;
+ cleanup:
+ return ret;
+}
+
+
/**
* virNetDevOpenvswitchVhostuserGetIfname:
* @path: the path of the unix socket
diff --git a/src/util/virnetdevopenvswitch.h b/src/util/virnetdevopenvswitch.h
index 6f6e620c22..331e483018 100644
--- a/src/util/virnetdevopenvswitch.h
+++ b/src/util/virnetdevopenvswitch.h
@@ -47,6 +47,9 @@ int virNetDevOpenvswitchAddPort(const char *brname,
int virNetDevOpenvswitchRemovePort(const char *brname, const char *ifname)
ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+int virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+
int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
@@ -57,6 +60,9 @@ int virNetDevOpenvswitchInterfaceStats(const char *ifname,
virDomainInterfaceStatsPtr stats)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
+int virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
+
int virNetDevOpenvswitchGetVhostuserIfname(const char *path,
char **ifname)
ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NOINLINE;
--
2.14.4
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On 07/02/2018 01:46 AM, Laine Stump wrote:
> This function retrieves the name of the OVS bridge that the given
> netdev is attached to. This separate function is necessary because OVS
> set the IFLA_MASTER attribute to "ovs-system" for all netdevs that are
> attached to an OVS bridge, so the standard method of retrieving the
> master can't be used.
>
> Signed-off-by: Laine Stump <laine@laine.org>
> ---
> src/libvirt_private.syms | 1 +
> src/util/virnetdevopenvswitch.c | 55 +++++++++++++++++++++++++++++++++++++++++
> src/util/virnetdevopenvswitch.h | 6 +++++
> 3 files changed, 62 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 98913a577a..386f53eeb9 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -2364,6 +2364,7 @@ virNetDevMidonetUnbindPort;
> virNetDevOpenvswitchAddPort;
> virNetDevOpenvswitchGetMigrateData;
> virNetDevOpenvswitchGetVhostuserIfname;
> +virNetDevOpenvswitchInterfaceGetMaster;
> virNetDevOpenvswitchInterfaceStats;
> virNetDevOpenvswitchRemovePort;
> virNetDevOpenvswitchSetMigrateData;
> diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
> index f86f698430..af3f2a773d 100644
> --- a/src/util/virnetdevopenvswitch.c
> +++ b/src/util/virnetdevopenvswitch.c
> @@ -404,6 +404,61 @@ virNetDevOpenvswitchInterfaceStats(const char *ifname,
> return ret;
> }
>
> +
> +/**
> + * virNetDeOpenvswitchGetMaster:
> + * @ifname: name of interface we're interested in
> + * @master: used to return a string containing the name of @ifname's "master"
> + * (this is the bridge or bond device that this device is attached to)
> + *
> + * Returns 0 on success, -1 on failure (if @ifname has no master
> + * @master will be NULL, but return value will still be 0 (success)).
> + *
> + * NB: This function is needed because the IFLA_MASTER attribute of an
> + * interface in a netlink dump (see virNetDevGetMaster()) will always
> + * return "ovs-system" for any interface that is attached to an OVS
> + * switch. When that happens, virNetDevOpenvswitchInterfaceGetMaster()
> + * must be called to get the "real" master of the interface.
> + */
> +int
> +virNetDevOpenvswitchInterfaceGetMaster(const char *ifname, char **master)
> +{
> + virCommandPtr cmd = NULL;
> + int ret = -1;
> + int exitstatus;
> +
> + *master = NULL;
> + cmd = virCommandNew(OVSVSCTL);
I'd put an empty line in between these two ^^ because from data POV we
have two different blocks (one initializes variables, the other
constructs @cmd). But it is really a nit pick.
> + virNetDevOpenvswitchAddTimeout(cmd);
> + virCommandAddArgList(cmd, "iface-to-br", ifname, NULL);
> + virCommandSetOutputBuffer(cmd, master);
> +
> + if (virCommandRun(cmd, &exitstatus) < 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Unable to run command to get OVS master for "
> + "interface %s"), ifname);
> + goto cleanup;
> + }
> +
> + /* non-0 exit code just means that the interface has no master in OVS */
> + if (exitstatus != 0)
> + VIR_FREE(*master);
A-ha! We indeed need to do this. I was under impression that just like
other functions of ours if they fail no allocation is done. But this is
different so we need to call VIR_FREE().
Michal
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On 07/02/2018 02:11 AM, Michal Prívozník wrote:
> On 07/02/2018 01:46 AM, Laine Stump wrote:
>> + virNetDevOpenvswitchAddTimeout(cmd);
>> + virCommandAddArgList(cmd, "iface-to-br", ifname, NULL);
>> + virCommandSetOutputBuffer(cmd, master);
>> +
>> + if (virCommandRun(cmd, &exitstatus) < 0) {
>> + virReportError(VIR_ERR_INTERNAL_ERROR,
>> + _("Unable to run command to get OVS master for "
>> + "interface %s"), ifname);
>> + goto cleanup;
>> + }
>> +
>> + /* non-0 exit code just means that the interface has no master in OVS */
>> + if (exitstatus != 0)
>> + VIR_FREE(*master);
> A-ha! We indeed need to do this. I was under impression that just like
> other functions of ours if they fail no allocation is done. But this is
> different so we need to call VIR_FREE().
Right. If ovs-vsctl is run and returns non-0, there still might have
been some sort of output to stdout (or there might not have been, but I
don't want to rely on it).
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