void (*rx_destruct)(struct netdev_rx *);
void (*rx_dealloc)(struct netdev_rx *);
- /* Attempts to receive a packet from 'rx' into the 'size' bytes in
- * 'buffer'. If successful, returns the number of bytes in the received
- * packet, otherwise a negative errno value. Returns -EAGAIN immediately
- * if no packet is ready to be received.
+ /* Attempts to receive a packet from 'rx' into the tailroom of 'buffer',
+ * which should initially be empty. If successful, returns 0 and
+ * increments 'buffer->size' by the number of bytes in the received packet,
+ * otherwise a positive errno value. Returns EAGAIN immediately if no
+ * packet is ready to be received.
*
- * Must return -EMSGSIZE, and discard the packet, if the received packet
- * is longer than 'size' bytes.
+ * Must return EMSGSIZE, and discard the packet, if the received packet
+ * is longer than 'ofpbuf_tailroom(buffer)'.
*
- * Specify NULL if this */
- int (*rx_recv)(struct netdev_rx *rx, void *buffer, size_t size);
+ * Implementations may make use of VLAN_HEADER_LEN bytes of tailroom to
+ * add a VLAN header which is obtained out-of-band to the packet. If
+ * this occurs then VLAN_HEADER_LEN bytes of tailroom will no longer be
+ * available for the packet, otherwise it may be used for the packet
+ * itself.
+ *
+ * It is advised that the tailroom of 'buffer' should be
+ * VLAN_HEADER_LEN bytes longer than the MTU to allow space for an
+ * out-of-band VLAN header to be added to the packet.
+ *
+ * This function may be set to null if it would always return EOPNOTSUPP
+ * anyhow. */
+ int (*rx_recv)(struct netdev_rx *rx, struct ofpbuf *buffer);
/* Registers with the poll loop to wake up from the next call to
* poll_block() when a packet is ready to be received with netdev_rx_recv()