* slave. If the switch does not support the specified 'algorithm' parameter,
* it should reject the action.
*
+ * Several algorithms take into account liveness when selecting slaves. The
+ * liveness of a slave is implementation defined (with one exception), but will
+ * generally take into account things like its carrier status and the results
+ * of any link monitoring protocols which happen to be running on it. In order
+ * to give controllers a place-holder value, the OFPP_NONE port is always
+ * considered live.
+ *
* Some slave selection strategies require the use of a hash function, in which
* case the 'fields' and 'basis' parameters should be populated. The 'fields'
* parameter (one of NX_HASH_FIELDS_*) designates which parts of the flow to
* Masking: Not maskable. */
#define NXM_NX_ND_TLL NXM_HEADER (0x0001, 25, 6)
+/* IP fragment information.
+ *
+ * Prereqs:
+ * NXM_OF_ETH_TYPE must be either 0x0800 or 0x86dd.
+ *
+ * Format: 8-bit value with one of the values 0, 1, or 3, as described below.
+ *
+ * Masking: Fully maskable.
+ *
+ * This field has three possible values:
+ *
+ * - A packet that is not an IP fragment has value 0.
+ *
+ * - A packet that is an IP fragment with offset 0 (the first fragment) has
+ * bit 0 set and thus value 1.
+ *
+ * - A packet that is an IP fragment with nonzero offset has bits 0 and 1 set
+ * and thus value 3.
+ *
+ * NX_IP_FRAG_ANY and NX_IP_FRAG_LATER are declared to symbolically represent
+ * the meanings of bits 0 and 1.
+ *
+ * The switch may reject matches against values that can never appear.
+ *
+ * It is important to understand how this field interacts with the OpenFlow IP
+ * fragment handling mode:
+ *
+ * - In OFPC_FRAG_DROP mode, the OpenFlow switch drops all IP fragments
+ * before they reach the flow table, so every packet that is available for
+ * matching will have value 0 in this field.
+ *
+ * - Open vSwitch does not implement OFPC_FRAG_REASM mode, but if it did then
+ * IP fragments would be reassembled before they reached the flow table and
+ * again every packet available for matching would always have value 0.
+ *
+ * - In OFPC_FRAG_NORMAL mode, all three values are possible, but OpenFlow
+ * 1.0 says that fragments' transport ports are always 0, even for the
+ * first fragment, so this does not provide much extra information.
+ *
+ * - In OFPC_FRAG_NX_MATCH mode, all three values are possible. For
+ * fragments with offset 0, Open vSwitch makes L4 header information
+ * available.
+ */
+#define NXM_NX_IP_FRAG NXM_HEADER (0x0001, 26, 1)
+#define NXM_NX_IP_FRAG_W NXM_HEADER_W(0x0001, 26, 1)
+
+/* Bits in the value of NXM_NX_IP_FRAG. */
+#define NX_IP_FRAG_ANY (1 << 0) /* Is this a fragment? */
+#define NX_IP_FRAG_LATER (1 << 1) /* Is this a fragment with nonzero offset? */
/* ## --------------------- ## */
/* ## Requests and replies. ## */