+struct flow_tnl;
+struct flow_wildcards;
+struct nlattr;
+struct ofpbuf;
+struct simap;
+
+#define ODPP_LOCAL ODP_PORT_C(OVSP_LOCAL)
+#define ODPP_NONE ODP_PORT_C(UINT32_MAX)
+
+void format_odp_actions(struct ds *, const struct nlattr *odp_actions,
+ size_t actions_len);
+int odp_actions_from_string(const char *, const struct simap *port_names,
+ struct ofpbuf *odp_actions);
+
+/* The maximum number of bytes that odp_flow_key_from_flow() appends to a
+ * buffer. This is the upper bound on the length of a nlattr-formatted flow
+ * key that ovs-vswitchd fully understands.
+ *
+ * OVS doesn't insist that ovs-vswitchd and the datapath have exactly the same
+ * idea of a flow, so therefore this value isn't necessarily an upper bound on
+ * the length of a flow key that the datapath can pass to ovs-vswitchd.
+ *
+ * The longest nlattr-formatted flow key appended by odp_flow_key_from_flow()
+ * would be:
+ *
+ * struct pad nl hdr total
+ * ------ --- ------ -----
+ * OVS_KEY_ATTR_PRIORITY 4 -- 4 8
+ * OVS_KEY_ATTR_TUNNEL 0 -- 4 4
+ * - OVS_TUNNEL_KEY_ATTR_ID 8 -- 4 12
+ * - OVS_TUNNEL_KEY_ATTR_IPV4_SRC 4 -- 4 8
+ * - OVS_TUNNEL_KEY_ATTR_IPV4_DST 4 -- 4 8
+ * - OVS_TUNNEL_KEY_ATTR_TOS 1 3 4 8
+ * - OVS_TUNNEL_KEY_ATTR_TTL 1 3 4 8
+ * - OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT 0 -- 4 4
+ * - OVS_TUNNEL_KEY_ATTR_CSUM 0 -- 4 4
+ * OVS_KEY_ATTR_IN_PORT 4 -- 4 8
+ * OVS_KEY_ATTR_SKB_MARK 4 -- 4 8
+ * OVS_KEY_ATTR_ETHERNET 12 -- 4 16
+ * OVS_KEY_ATTR_ETHERTYPE 2 2 4 8 (outer VLAN ethertype)
+ * OVS_KEY_ATTR_8021Q 4 -- 4 8
+ * OVS_KEY_ATTR_ENCAP 0 -- 4 4 (VLAN encapsulation)
+ * OVS_KEY_ATTR_ETHERTYPE 2 2 4 8 (inner VLAN ethertype)
+ * OVS_KEY_ATTR_IPV6 40 -- 4 44
+ * OVS_KEY_ATTR_ICMPV6 2 2 4 8
+ * OVS_KEY_ATTR_ND 28 -- 4 32
+ * ----------------------------------------------------------
+ * total 208
+ *
+ * We include some slack space in case the calculation isn't quite right or we
+ * add another field and forget to adjust this value.
+ */
+#define ODPUTIL_FLOW_KEY_BYTES 256
+
+/* A buffer with sufficient size and alignment to hold an nlattr-formatted flow
+ * key. An array of "struct nlattr" might not, in theory, be sufficiently
+ * aligned because it only contains 16-bit types. */
+struct odputil_keybuf {
+ uint32_t keybuf[DIV_ROUND_UP(ODPUTIL_FLOW_KEY_BYTES, 4)];
+};