some but not all of them. However, this behavior may change in future versions.
+Unique flow identifiers
+-----------------------
+
+An alternative to using the original match portion of a key as the handle for
+flow identification is a unique flow identifier, or "UFID". UFIDs are optional
+for both the kernel and user space program.
+
+User space programs that support UFID are expected to provide it during flow
+setup in addition to the flow, then refer to the flow using the UFID for all
+future operations. The kernel is not required to index flows by the original
+flow key if a UFID is specified.
+
+
Basic rule for evolving flow keys
---------------------------------
* a wildcarded match. Omitting attribute is treated as wildcarding all
* corresponding fields. Optional for all requests. If not present,
* all flow key bits are exact match bits.
+ * @OVS_FLOW_ATTR_UFID: A unique identifier for the flow. Causes the flow to
+ * be indexed by this value rather than the %OVS_FLOW_ATTR_KEY%. Optional
+ * for all requests. Present in notifications if the flow was created with a
+ * UFID.
+ * @OVS_FLOW_ATTR_UFID_FLAGS: A 32-bit value of OR'd OVS_UFID_F_* flags that
+ * provide alternative semantics for flow installation and retrieval. Optional
+ * for all requests.
*
* These attributes follow the &struct ovs_header within the Generic Netlink
* payload for %OVS_FLOW_* commands.
OVS_FLOW_ATTR_MASK, /* Sequence of OVS_KEY_ATTR_* attributes. */
OVS_FLOW_ATTR_PROBE, /* Flow operation is a feature probe, error
* logging should be suppressed. */
+ OVS_FLOW_ATTR_UFID, /* Variable length unique flow identifier. */
+ OVS_FLOW_ATTR_UFID_FLAGS,/* u32 of OVS_UFID_F_*. */
__OVS_FLOW_ATTR_MAX
};
#define OVS_FLOW_ATTR_MAX (__OVS_FLOW_ATTR_MAX - 1)
+/**
+ * Omit attributes for notifications.
+ *
+ * If a datapath request contains an OVS_UFID_F_OMIT_* flag, then the datapath
+ * may omit the corresponding 'ovs_flow_attr' from the response.
+ */
+#define OVS_UFID_F_OMIT_KEY (1 << 0)
+#define OVS_UFID_F_OMIT_MASK (1 << 1)
+#define OVS_UFID_F_OMIT_ACTIONS (1 << 2)
+
/**
* enum ovs_sample_attr - Attributes for %OVS_ACTION_ATTR_SAMPLE action.
* @OVS_SAMPLE_ATTR_PROBABILITY: 32-bit fraction of packets to sample with