[libvirt] [PATCH 2/3] openvswitch: Add utility functions for getting and setting Open vSwitch per-port data

[Kyle Mestery]

Add utility functions for Open vSwitch to both save
per-port data before a live migration, and restore the
per-port data after a live migration.

Signed-off-by: Kyle Mestery <kmestery at cisco.com>
---
 src/libvirt_private.syms        |  2 ++
 src/util/virnetdevopenvswitch.c | 70 +++++++++++++++++++++++++++++++++++++++++
 src/util/virnetdevopenvswitch.h |  6 ++++
 3 files changed, 78 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index eebc52a..449744e 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1477,7 +1477,9 @@ virNetDevMacVLanVPortProfileRegisterCallback;
 
 # virnetdevopenvswitch.h
 virNetDevOpenvswitchAddPort;
+virNetDevOpenvswitchGetMigrateData;
 virNetDevOpenvswitchRemovePort;
+virNetDevOpenvswitchSetMigrateData;
 
 
 # virnetdevtap.h
diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
index a6993b6..841f693 100644
--- a/src/util/virnetdevopenvswitch.c
+++ b/src/util/virnetdevopenvswitch.c
@@ -179,3 +179,73 @@ int virNetDevOpenvswitchRemovePort(const char *brname ATTRIBUTE_UNUSED, const ch
         virCommandFree(cmd);
         return ret;
 }
+
+/**
+ * virNetDevOpenvswitchGetMigrateData:
+ * @migrate: a pointer to store the data into, allocated by this function
+ * @ifname: name of the interface for which data is being migrated
+ *
+ * Allocates data to be migrated specific to Open vSwitch
+ *
+ * Returns 0 in case of success or -1 in case of failure
+ */
+int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
+{
+    virCommandPtr cmd = NULL;
+    int ret = 0;
+
+    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "get", "Interface",
+                               ifname, "external_ids:PortData", NULL);
+
+    virCommandSetOutputBuffer(cmd, migrate);
+
+    /* Run the command */
+    if (virCommandRun(cmd, NULL) < 0) {
+        virReportSystemError(VIR_ERR_INTERNAL_ERROR,
+                             _("Unable to run command to get OVS port data for "
+                             "interface %s"), ifname);
+        ret = -1;
+        goto error;
+    }
+
+    /* Wipeout the newline */
+    (*migrate)[strlen(*migrate) - 1] = '\0';
+
+error:
+    return ret;
+}
+
+/**
+ * virNetDevOpenvswitchSetMigrateData:
+ * @migrate: the data which was transferred during migration
+ * @ifname: the name of the interface the data is associated with
+ *
+ * Repopulates OVS per-port data on destination host
+ *
+ * Returns 0 in case of success or -1 in case of failure
+ */
+int virNetDevOpenvswitchSetMigrateData(char *migrate, const char *ifname)
+{
+    virCommandPtr cmd = NULL;
+    int ret = 0;
+    virBufferPtr buf;
+
+    if (VIR_ALLOC(buf) < 0) {
+        ret = -1;
+        goto error;
+    }
+
+    virBufferAsprintf(buf, "external_ids:PortData=%s", migrate);
+
+    cmd = virCommandNewArgList(OVSVSCTL, "--timeout=5", "set", "Interface", ifname,
+                               virBufferCurrentContent(buf), NULL);
+    /* Run the command */
+    if ((ret = virCommandRun(cmd, NULL)) < 0) {
+        virReportSystemError(VIR_ERR_INTERNAL_ERROR,
+                             _("Unable to run command to set OVS port data for "
+                             "interface %s"), ifname);
+    }
+
+error:
+    return ret;
+}
diff --git a/src/util/virnetdevopenvswitch.h b/src/util/virnetdevopenvswitch.h
index 7e5b618..147cd6f 100644
--- a/src/util/virnetdevopenvswitch.h
+++ b/src/util/virnetdevopenvswitch.h
@@ -42,4 +42,10 @@ int virNetDevOpenvswitchAddPort(const char *brname,
 int virNetDevOpenvswitchRemovePort(const char *brname, const char *ifname)
     ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 
+int virNetDevOpenvswitchGetMigrateData(char **migrate, const char *ifname)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+
+int virNetDevOpenvswitchSetMigrateData(char *migrate, const char *ifname)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+
 #endif /* __VIR_NETDEV_OPENVSWITCH_H__ */
-- 
1.7.11.4