-(see Section 9.4.6 "Receive, Process and Transmit Packet's").
-
-.. code-block:: c
-
- /**
- * Interface to dequeue mbufs from tx_q and burst tx
- */
-
- static void
-
- kni_egress(struct kni_port_params *p)
- {
- uint8_t i, nb_kni, port_id;
- unsigned nb_tx, num;
- struct rte_mbuf *pkts_burst[PKT_BURST_SZ];
-
- if (p == NULL)
- return;
-
- nb_kni = p->nb_kni;
- port_id = p->port_id;
-
- for (i = 0; i < nb_kni; i++) {
- /* Burst rx from kni */
- num = rte_kni_rx_burst(p->kni[i], pkts_burst, PKT_BURST_SZ);
- if (unlikely(num > PKT_BURST_SZ)) {
- RTE_LOG(ERR, APP, "Error receiving from KNI\n");
- return;
- }
-
- /* Burst tx to eth */
-
- nb_tx = rte_eth_tx_burst(port_id, 0, pkts_burst, (uint16_t)num);
-
- kni_stats[port_id].tx_packets += nb_tx;
-
- if (unlikely(nb_tx < num)) {
- /* Free mbufs not tx to NIC */
- kni_burst_free_mbufs(&pkts_burst[nb_tx], num - nb_tx);
- kni_stats[port_id].tx_dropped += num - nb_tx;
- }
- }
- }
-
-Callbacks for Kernel Requests
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-To execute specific PMD operations in user space requested by some Linux* commands,
-callbacks must be implemented and filled in the struct rte_kni_ops structure.
-Currently, setting a new MTU and configuring the network interface (up/ down) are supported.
-
-.. code-block:: c
-
- static struct rte_kni_ops kni_ops = {
- .change_mtu = kni_change_mtu,
- .config_network_if = kni_config_network_interface,
- };
-
- /* Callback for request of changing MTU */
-
- static int
- kni_change_mtu(uint8_t port_id, unsigned new_mtu)
- {
- int ret;
- struct rte_eth_conf conf;
-
- if (port_id >= rte_eth_dev_count()) {
- RTE_LOG(ERR, APP, "Invalid port id %d\n", port_id);
- return -EINVAL;
- }
-
- RTE_LOG(INFO, APP, "Change MTU of port %d to %u\n", port_id, new_mtu);
-
- /* Stop specific port */
-
- rte_eth_dev_stop(port_id);
-
- memcpy(&conf, &port_conf, sizeof(conf));
-
- /* Set new MTU */
-
- if (new_mtu > ETHER_MAX_LEN)
- conf.rxmode.jumbo_frame = 1;
- else
- conf.rxmode.jumbo_frame = 0;
-
- /* mtu + length of header + length of FCS = max pkt length */
-
- conf.rxmode.max_rx_pkt_len = new_mtu + KNI_ENET_HEADER_SIZE + KNI_ENET_FCS_SIZE;
-
- ret = rte_eth_dev_configure(port_id, 1, 1, &conf);
- if (ret < 0) {
- RTE_LOG(ERR, APP, "Fail to reconfigure port %d\n", port_id);
- return ret;
- }
-
- /* Restart specific port */
-
- ret = rte_eth_dev_start(port_id);
- if (ret < 0) {
- RTE_LOG(ERR, APP, "Fail to restart port %d\n", port_id);
- return ret;
- }
-
- return 0;
- }
-
- /* Callback for request of configuring network interface up/down */
-
- static int
- kni_config_network_interface(uint8_t port_id, uint8_t if_up)
- {
- int ret = 0;
-
- if (port_id >= rte_eth_dev_count() || port_id >= RTE_MAX_ETHPORTS) {
- RTE_LOG(ERR, APP, "Invalid port id %d\n", port_id);
- return -EINVAL;
- }
-
- RTE_LOG(INFO, APP, "Configure network interface of %d %s\n",
-
- port_id, if_up ? "up" : "down");
-
- if (if_up != 0) {
- /* Configure network interface up */
- rte_eth_dev_stop(port_id);
- ret = rte_eth_dev_start(port_id);
- } else /* Configure network interface down */
- rte_eth_dev_stop(port_id);
-
- if (ret < 0)
- RTE_LOG(ERR, APP, "Failed to start port %d\n", port_id);
- return ret;
- }
-
-.. |kernel_nic| image:: img/kernel_nic.*