/* Returns the Netlink PID value to supply in OVS_ACTION_ATTR_USERSPACE
* actions as the OVS_USERSPACE_ATTR_PID attribute's value, for use in
- * flows whose packets arrived on port 'port_no'.
+ * flows whose packets arrived on port 'port_no'. In the case where the
+ * provider allocates multiple Netlink PIDs to a single port, it may use
+ * 'hash' to spread load among them. The caller need not use a particular
+ * hash function; a 5-tuple hash is suitable.
+ *
+ * (The datapath implementation might use some different hash function for
+ * distributing packets received via flow misses among PIDs. This means
+ * that packets received via flow misses might be reordered relative to
+ * packets received via userspace actions. This is not ordinarily a
+ * problem.)
*
* A 'port_no' of UINT32_MAX should be treated as a special case. The
* implementation should return a reserved PID, not allocated to any port,
*
* A dpif provider that doesn't have meaningful Netlink PIDs can use NULL
* for this function. This is equivalent to always returning 0. */
- uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no);
+ uint32_t (*port_get_pid)(const struct dpif *dpif, odp_port_t port_no,
+ uint32_t hash);
/* Attempts to begin dumping the ports in a dpif. On success, returns 0
* and initializes '*statep' with any data needed for iteration. On
* updating flows as necessary if it does this. */
int (*recv_set)(struct dpif *dpif, bool enable);
+ /* Refreshes the poll loops and Netlink sockets associated to each port,
+ * when the number of upcall handlers (upcall receiving thread) is changed
+ * to 'n_handlers' and receiving packets for 'dpif' is enabled by
+ * recv_set().
+ *
+ * Since multiple upcall handlers can read upcalls simultaneously from
+ * 'dpif', each port can have multiple Netlink sockets, one per upcall
+ * handler. So, handlers_set() is responsible for the following tasks:
+ *
+ * When receiving upcall is enabled, extends or creates the
+ * configuration to support:
+ *
+ * - 'n_handlers' Netlink sockets for each port.
+ *
+ * - 'n_handlers' poll loops, one for each upcall handler.
+ *
+ * - registering the Netlink sockets for the same upcall handler to
+ * the corresponding poll loop.
+ * */
+ int (*handlers_set)(struct dpif *dpif, uint32_t n_handlers);
+
/* Translates OpenFlow queue ID 'queue_id' (in host byte order) into a
* priority value used for setting packet priority. */
int (*queue_to_priority)(const struct dpif *dpif, uint32_t queue_id,
uint32_t *priority);
- /* Polls for an upcall from 'dpif'. If successful, stores the upcall into
- * '*upcall', using 'buf' for storage. Should only be called if 'recv_set'
- * has been used to enable receiving packets from 'dpif'.
+ /* Polls for an upcall from 'dpif' for an upcall handler. Since there
+ * can be multiple poll loops (see ->handlers_set()), 'handler_id' is
+ * needed as index to identify the corresponding poll loop. If
+ * successful, stores the upcall into '*upcall', using 'buf' for
+ * storage. Should only be called if 'recv_set' has been used to enable
+ * receiving packets from 'dpif'.
*
* The implementation should point 'upcall->key' and 'upcall->userdata'
* (if any) into data in the caller-provided 'buf'. The implementation may
*
* This function must not block. If no upcall is pending when it is
* called, it should return EAGAIN without blocking. */
- int (*recv)(struct dpif *dpif, struct dpif_upcall *upcall,
- struct ofpbuf *buf);
-
- /* Arranges for the poll loop to wake up when 'dpif' has a message queued
- * to be received with the recv member function. */
- void (*recv_wait)(struct dpif *dpif);
+ int (*recv)(struct dpif *dpif, uint32_t handler_id,
+ struct dpif_upcall *upcall, struct ofpbuf *buf);
+
+ /* Arranges for the poll loop for an upcall handler to wake up when 'dpif'
+ * has a message queued to be received with the recv member functions.
+ * Since there can be multiple poll loops (see ->handlers_set()),
+ * 'handler_id' is needed as index to identify the corresponding poll loop.
+ * */
+ void (*recv_wait)(struct dpif *dpif, uint32_t handler_id);
/* Throws away any queued upcalls that 'dpif' currently has ready to
* return. */