Imported Upstream version 16.04
[deb_dpdk.git] / examples / tep_termination / main.c
diff --git a/examples/tep_termination/main.c b/examples/tep_termination/main.c
new file mode 100644 (file)
index 0000000..f97d552
--- /dev/null
@@ -0,0 +1,1275 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arpa/inet.h>
+#include <getopt.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <linux/virtio_net.h>
+#include <linux/virtio_ring.h>
+#include <signal.h>
+#include <stdint.h>
+#include <sys/eventfd.h>
+#include <sys/param.h>
+#include <unistd.h>
+
+#include <rte_atomic.h>
+#include <rte_cycles.h>
+#include <rte_ethdev.h>
+#include <rte_log.h>
+#include <rte_string_fns.h>
+#include <rte_malloc.h>
+#include <rte_virtio_net.h>
+
+#include "main.h"
+#include "vxlan.h"
+#include "vxlan_setup.h"
+
+/* the maximum number of external ports supported */
+#define MAX_SUP_PORTS 1
+
+/**
+ * Calculate the number of buffers needed per port
+ */
+#define NUM_MBUFS_PER_PORT ((MAX_QUEUES * RTE_TEST_RX_DESC_DEFAULT) +\
+                               (nb_switching_cores * MAX_PKT_BURST) +\
+                               (nb_switching_cores * \
+                               RTE_TEST_TX_DESC_DEFAULT) +\
+                               (nb_switching_cores * MBUF_CACHE_SIZE))
+
+#define MBUF_CACHE_SIZE 128
+#define MBUF_SIZE (2048 + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM)
+
+#define MAX_PKT_BURST 32       /* Max burst size for RX/TX */
+#define BURST_TX_DRAIN_US 100  /* TX drain every ~100us */
+
+/* Defines how long we wait between retries on RX */
+#define BURST_RX_WAIT_US 15
+
+#define BURST_RX_RETRIES 4     /* Number of retries on RX. */
+
+#define JUMBO_FRAME_MAX_SIZE    0x2600
+
+/* State of virtio device. */
+#define DEVICE_MAC_LEARNING 0
+#define DEVICE_RX          1
+#define DEVICE_SAFE_REMOVE  2
+
+/* Config_core_flag status definitions. */
+#define REQUEST_DEV_REMOVAL 1
+#define ACK_DEV_REMOVAL     0
+
+/* Configurable number of RX/TX ring descriptors */
+#define RTE_TEST_RX_DESC_DEFAULT 1024
+#define RTE_TEST_TX_DESC_DEFAULT 512
+
+/* Get first 4 bytes in mbuf headroom. */
+#define MBUF_HEADROOM_UINT32(mbuf) (*(uint32_t *)((uint8_t *)(mbuf) \
+               + sizeof(struct rte_mbuf)))
+
+#define INVALID_PORT_ID 0xFF
+
+/* Size of buffers used for snprintfs. */
+#define MAX_PRINT_BUFF 6072
+
+/* Maximum character device basename size. */
+#define MAX_BASENAME_SZ 20
+
+/* Maximum long option length for option parsing. */
+#define MAX_LONG_OPT_SZ 64
+
+/* Used to compare MAC addresses. */
+#define MAC_ADDR_CMP 0xFFFFFFFFFFFFULL
+
+#define CMD_LINE_OPT_NB_DEVICES "nb-devices"
+#define CMD_LINE_OPT_UDP_PORT "udp-port"
+#define CMD_LINE_OPT_TX_CHECKSUM "tx-checksum"
+#define CMD_LINE_OPT_TSO_SEGSZ "tso-segsz"
+#define CMD_LINE_OPT_FILTER_TYPE "filter-type"
+#define CMD_LINE_OPT_ENCAP "encap"
+#define CMD_LINE_OPT_DECAP "decap"
+#define CMD_LINE_OPT_RX_RETRY "rx-retry"
+#define CMD_LINE_OPT_RX_RETRY_DELAY "rx-retry-delay"
+#define CMD_LINE_OPT_RX_RETRY_NUM "rx-retry-num"
+#define CMD_LINE_OPT_STATS "stats"
+#define CMD_LINE_OPT_DEV_BASENAME "dev-basename"
+
+/* mask of enabled ports */
+static uint32_t enabled_port_mask;
+
+/*Number of switching cores enabled*/
+static uint32_t nb_switching_cores;
+
+/* number of devices/queues to support*/
+uint16_t nb_devices = 2;
+
+/* max ring descriptor, ixgbe, i40e, e1000 all are 4096. */
+#define MAX_RING_DESC 4096
+
+struct vpool {
+       struct rte_mempool *pool;
+       struct rte_ring *ring;
+       uint32_t buf_size;
+} vpool_array[MAX_QUEUES+MAX_QUEUES];
+
+/* UDP tunneling port */
+uint16_t udp_port = 4789;
+
+/* enable/disable inner TX checksum */
+uint8_t tx_checksum = 0;
+
+/* TCP segment size */
+uint16_t tso_segsz = 0;
+
+/* enable/disable decapsulation */
+uint8_t rx_decap = 1;
+
+/* enable/disable encapsulation */
+uint8_t tx_encap = 1;
+
+/* RX filter type for tunneling packet */
+uint8_t filter_idx = 1;
+
+/* overlay packet operation */
+struct ol_switch_ops overlay_options = {
+       .port_configure = vxlan_port_init,
+       .tunnel_setup = vxlan_link,
+       .tunnel_destroy = vxlan_unlink,
+       .tx_handle = vxlan_tx_pkts,
+       .rx_handle = vxlan_rx_pkts,
+       .param_handle = NULL,
+};
+
+/* Enable stats. */
+uint32_t enable_stats = 0;
+/* Enable retries on RX. */
+static uint32_t enable_retry = 1;
+/* Specify timeout (in useconds) between retries on RX. */
+static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
+/* Specify the number of retries on RX. */
+static uint32_t burst_rx_retry_num = BURST_RX_RETRIES;
+
+/* Character device basename. Can be set by user. */
+static char dev_basename[MAX_BASENAME_SZ] = "vhost-net";
+
+static unsigned lcore_ids[RTE_MAX_LCORE];
+uint8_t ports[RTE_MAX_ETHPORTS];
+
+static unsigned nb_ports; /**< The number of ports specified in command line */
+
+/* ethernet addresses of ports */
+struct ether_addr ports_eth_addr[RTE_MAX_ETHPORTS];
+
+/* heads for the main used and free linked lists for the data path. */
+static struct virtio_net_data_ll *ll_root_used;
+static struct virtio_net_data_ll *ll_root_free;
+
+/**
+ * Array of data core structures containing information on
+ * individual core linked lists.
+ */
+static struct lcore_info lcore_info[RTE_MAX_LCORE];
+
+/* Used for queueing bursts of TX packets. */
+struct mbuf_table {
+       unsigned len;
+       unsigned txq_id;
+       struct rte_mbuf *m_table[MAX_PKT_BURST];
+};
+
+/* TX queue for each data core. */
+struct mbuf_table lcore_tx_queue[RTE_MAX_LCORE];
+
+struct device_statistics dev_statistics[MAX_DEVICES];
+
+/**
+ * Set character device basename.
+ */
+static int
+us_vhost_parse_basename(const char *q_arg)
+{
+       /* parse number string */
+       if (strlen(q_arg) >= MAX_BASENAME_SZ)
+               return -1;
+       else
+               snprintf((char *)&dev_basename, MAX_BASENAME_SZ, "%s", q_arg);
+
+       return 0;
+}
+
+/**
+ * Parse the portmask provided at run time.
+ */
+static int
+parse_portmask(const char *portmask)
+{
+       char *end = NULL;
+       unsigned long pm;
+
+       /* parse hexadecimal string */
+       pm = strtoul(portmask, &end, 16);
+       if ((portmask[0] == '\0') || (end == NULL) || (*end != '\0'))
+               return -1;
+
+       if (pm == 0)
+               return -1;
+
+       return pm;
+}
+
+/**
+ * Parse num options at run time.
+ */
+static int
+parse_num_opt(const char *q_arg, uint32_t max_valid_value)
+{
+       char *end = NULL;
+       unsigned long num;
+
+       /* parse unsigned int string */
+       num = strtoul(q_arg, &end, 10);
+       if ((q_arg[0] == '\0') || (end == NULL) || (*end != '\0'))
+               return -1;
+
+       if (num > max_valid_value)
+               return -1;
+
+       return num;
+}
+
+/**
+ * Display usage
+ */
+static void
+tep_termination_usage(const char *prgname)
+{
+       RTE_LOG(INFO, VHOST_CONFIG, "%s [EAL options] -- -p PORTMASK\n"
+       "               --udp-port: UDP destination port for VXLAN packet\n"
+       "               --nb-devices[1-64]: The number of virtIO device\n"
+       "               --tx-checksum [0|1]: inner Tx checksum offload\n"
+       "               --tso-segsz [0-N]: TCP segment size\n"
+       "               --decap [0|1]: tunneling packet decapsulation\n"
+       "               --encap [0|1]: tunneling packet encapsulation\n"
+       "               --filter-type[1-3]: filter type for tunneling packet\n"
+       "                   1: Inner MAC and tenent ID\n"
+       "                   2: Inner MAC and VLAN, and tenent ID\n"
+       "                   3: Outer MAC, Inner MAC and tenent ID\n"
+       "               -p PORTMASK: Set mask for ports to be used by application\n"
+       "               --rx-retry [0|1]: disable/enable(default) retries on rx."
+       "                Enable retry if destintation queue is full\n"
+       "               --rx-retry-delay [0-N]: timeout(in usecond) between retries on RX."
+       "                This makes effect only if retries on rx enabled\n"
+       "               --rx-retry-num [0-N]: the number of retries on rx."
+       "                This makes effect only if retries on rx enabled\n"
+       "               --stats [0-N]: 0: Disable stats, N: Time in seconds to print stats\n"
+       "               --dev-basename: The basename to be used for the character device.\n",
+              prgname);
+}
+
+/**
+ * Parse the arguments given in the command line of the application.
+ */
+static int
+tep_termination_parse_args(int argc, char **argv)
+{
+       int opt, ret;
+       int option_index;
+       unsigned i;
+       const char *prgname = argv[0];
+       static struct option long_option[] = {
+               {CMD_LINE_OPT_NB_DEVICES, required_argument, NULL, 0},
+               {CMD_LINE_OPT_UDP_PORT, required_argument, NULL, 0},
+               {CMD_LINE_OPT_TX_CHECKSUM, required_argument, NULL, 0},
+               {CMD_LINE_OPT_TSO_SEGSZ, required_argument, NULL, 0},
+               {CMD_LINE_OPT_DECAP, required_argument, NULL, 0},
+               {CMD_LINE_OPT_ENCAP, required_argument, NULL, 0},
+               {CMD_LINE_OPT_FILTER_TYPE, required_argument, NULL, 0},
+               {CMD_LINE_OPT_RX_RETRY, required_argument, NULL, 0},
+               {CMD_LINE_OPT_RX_RETRY_DELAY, required_argument, NULL, 0},
+               {CMD_LINE_OPT_RX_RETRY_NUM, required_argument, NULL, 0},
+               {CMD_LINE_OPT_STATS, required_argument, NULL, 0},
+               {CMD_LINE_OPT_DEV_BASENAME, required_argument, NULL, 0},
+               {NULL, 0, 0, 0},
+       };
+
+       /* Parse command line */
+       while ((opt = getopt_long(argc, argv, "p:",
+                       long_option, &option_index)) != EOF) {
+               switch (opt) {
+               /* Portmask */
+               case 'p':
+                       enabled_port_mask = parse_portmask(optarg);
+                       if (enabled_port_mask == 0) {
+                               RTE_LOG(INFO, VHOST_CONFIG,
+                                       "Invalid portmask\n");
+                               tep_termination_usage(prgname);
+                               return -1;
+                       }
+                       break;
+               case 0:
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_NB_DEVICES,
+                               sizeof(CMD_LINE_OPT_NB_DEVICES))) {
+                               ret = parse_num_opt(optarg, MAX_DEVICES);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                       "Invalid argument for nb-devices [0-%d]\n",
+                                       MAX_DEVICES);
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       nb_devices = ret;
+                       }
+
+                       /* Enable/disable retries on RX. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_RX_RETRY,
+                               sizeof(CMD_LINE_OPT_RX_RETRY))) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for rx-retry [0|1]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       enable_retry = ret;
+                       }
+
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_TSO_SEGSZ,
+                               sizeof(CMD_LINE_OPT_TSO_SEGSZ))) {
+                               ret = parse_num_opt(optarg, INT16_MAX);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for TCP segment size [0-N]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       tso_segsz = ret;
+                       }
+
+                       if (!strncmp(long_option[option_index].name,
+                                       CMD_LINE_OPT_UDP_PORT,
+                                       sizeof(CMD_LINE_OPT_UDP_PORT))) {
+                               ret = parse_num_opt(optarg, INT16_MAX);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for UDP port [0-N]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       udp_port = ret;
+                       }
+
+                       /* Specify the retries delay time (in useconds) on RX.*/
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_RX_RETRY_DELAY,
+                               sizeof(CMD_LINE_OPT_RX_RETRY_DELAY))) {
+                               ret = parse_num_opt(optarg, INT32_MAX);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for rx-retry-delay [0-N]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       burst_rx_delay_time = ret;
+                       }
+
+                       /* Specify the retries number on RX. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_RX_RETRY_NUM,
+                               sizeof(CMD_LINE_OPT_RX_RETRY_NUM))) {
+                               ret = parse_num_opt(optarg, INT32_MAX);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for rx-retry-num [0-N]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       burst_rx_retry_num = ret;
+                       }
+
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_TX_CHECKSUM,
+                               sizeof(CMD_LINE_OPT_TX_CHECKSUM))) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for tx-checksum [0|1]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       tx_checksum = ret;
+                       }
+
+                       if (!strncmp(long_option[option_index].name,
+                                       CMD_LINE_OPT_FILTER_TYPE,
+                                       sizeof(CMD_LINE_OPT_FILTER_TYPE))) {
+                               ret = parse_num_opt(optarg, 3);
+                               if ((ret == -1) || (ret == 0)) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for filter type [1-3]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       filter_idx = ret - 1;
+                       }
+
+                       /* Enable/disable encapsulation on RX. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_DECAP,
+                               sizeof(CMD_LINE_OPT_DECAP))) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for decap [0|1]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       rx_decap = ret;
+                       }
+
+                       /* Enable/disable encapsulation on TX. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_ENCAP,
+                               sizeof(CMD_LINE_OPT_ENCAP))) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for encap [0|1]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       tx_encap = ret;
+                       }
+
+                       /* Enable/disable stats. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_STATS,
+                               sizeof(CMD_LINE_OPT_STATS))) {
+                               ret = parse_num_opt(optarg, INT32_MAX);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                                       "Invalid argument for stats [0..N]\n");
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               } else
+                                       enable_stats = ret;
+                       }
+
+                       /* Set character device basename. */
+                       if (!strncmp(long_option[option_index].name,
+                               CMD_LINE_OPT_DEV_BASENAME,
+                               sizeof(CMD_LINE_OPT_DEV_BASENAME))) {
+                               if (us_vhost_parse_basename(optarg) == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG,
+                                               "Invalid argument for character "
+                                               "device basename (Max %d characters)\n",
+                                               MAX_BASENAME_SZ);
+                                       tep_termination_usage(prgname);
+                                       return -1;
+                               }
+                       }
+
+                       break;
+
+                       /* Invalid option - print options. */
+               default:
+                       tep_termination_usage(prgname);
+                       return -1;
+               }
+       }
+
+       for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
+               if (enabled_port_mask & (1 << i))
+                       ports[nb_ports++] = (uint8_t)i;
+       }
+
+       if ((nb_ports ==  0) || (nb_ports > MAX_SUP_PORTS)) {
+               RTE_LOG(INFO, VHOST_PORT, "Current enabled port number is %u,"
+                       "but only %u port can be enabled\n", nb_ports,
+                       MAX_SUP_PORTS);
+               return -1;
+       }
+
+       return 0;
+}
+
+/**
+ * Update the global var NB_PORTS and array PORTS
+ * according to system ports number and return valid ports number
+ */
+static unsigned
+check_ports_num(unsigned max_nb_ports)
+{
+       unsigned valid_nb_ports = nb_ports;
+       unsigned portid;
+
+       if (nb_ports > max_nb_ports) {
+               RTE_LOG(INFO, VHOST_PORT, "\nSpecified port number(%u) "
+                       " exceeds total system port number(%u)\n",
+                       nb_ports, max_nb_ports);
+               nb_ports = max_nb_ports;
+       }
+
+       for (portid = 0; portid < nb_ports; portid++) {
+               if (ports[portid] >= max_nb_ports) {
+                       RTE_LOG(INFO, VHOST_PORT,
+                               "\nSpecified port ID(%u) exceeds max "
+                               " system port ID(%u)\n",
+                               ports[portid], (max_nb_ports - 1));
+                       ports[portid] = INVALID_PORT_ID;
+                       valid_nb_ports--;
+               }
+       }
+       return valid_nb_ports;
+}
+
+/**
+ * This function routes the TX packet to the correct interface. This may be a local device
+ * or the physical port.
+ */
+static inline void __attribute__((always_inline))
+virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m)
+{
+       struct mbuf_table *tx_q;
+       struct rte_mbuf **m_table;
+       unsigned len, ret = 0;
+       const uint16_t lcore_id = rte_lcore_id();
+       struct virtio_net *dev = vdev->dev;
+
+       LOG_DEBUG(VHOST_DATA, "(%"PRIu64") TX: MAC address is external\n",
+               dev->device_fh);
+
+       /* Add packet to the port tx queue */
+       tx_q = &lcore_tx_queue[lcore_id];
+       len = tx_q->len;
+
+       tx_q->m_table[len] = m;
+       len++;
+       if (enable_stats) {
+               dev_statistics[dev->device_fh].tx_total++;
+               dev_statistics[dev->device_fh].tx++;
+       }
+
+       if (unlikely(len == MAX_PKT_BURST)) {
+               m_table = (struct rte_mbuf **)tx_q->m_table;
+               ret = overlay_options.tx_handle(ports[0],
+                       (uint16_t)tx_q->txq_id, m_table,
+                       (uint16_t)tx_q->len);
+
+               /* Free any buffers not handled by TX and update
+                * the port stats.
+                */
+               if (unlikely(ret < len)) {
+                       do {
+                               rte_pktmbuf_free(m_table[ret]);
+                       } while (++ret < len);
+               }
+
+               len = 0;
+       }
+
+       tx_q->len = len;
+       return;
+}
+
+/**
+ * This function is called by each data core. It handles all
+ * RX/TX registered with the core. For TX the specific lcore
+ * linked list is used. For RX, MAC addresses are compared
+ * with all devices in the main linked list.
+ */
+static int
+switch_worker(__rte_unused void *arg)
+{
+       struct rte_mempool *mbuf_pool = arg;
+       struct virtio_net *dev = NULL;
+       struct vhost_dev *vdev = NULL;
+       struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
+       struct virtio_net_data_ll *dev_ll;
+       struct mbuf_table *tx_q;
+       volatile struct lcore_ll_info *lcore_ll;
+       const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1)
+                                       / US_PER_S * BURST_TX_DRAIN_US;
+       uint64_t prev_tsc, diff_tsc, cur_tsc, ret_count = 0;
+       unsigned i, ret = 0;
+       const uint16_t lcore_id = rte_lcore_id();
+       const uint16_t num_cores = (uint16_t)rte_lcore_count();
+       uint16_t rx_count = 0;
+       uint16_t tx_count;
+       uint32_t retry = 0;
+
+       RTE_LOG(INFO, VHOST_DATA, "Procesing on Core %u started\n", lcore_id);
+       lcore_ll = lcore_info[lcore_id].lcore_ll;
+       prev_tsc = 0;
+
+       tx_q = &lcore_tx_queue[lcore_id];
+       for (i = 0; i < num_cores; i++) {
+               if (lcore_ids[i] == lcore_id) {
+                       tx_q->txq_id = i;
+                       break;
+               }
+       }
+
+       while (1) {
+               cur_tsc = rte_rdtsc();
+               /*
+                * TX burst queue drain
+                */
+               diff_tsc = cur_tsc - prev_tsc;
+               if (unlikely(diff_tsc > drain_tsc)) {
+
+                       if (tx_q->len) {
+                               LOG_DEBUG(VHOST_DATA, "TX queue drained after "
+                                       "timeout with burst size %u\n",
+                                       tx_q->len);
+                               ret = overlay_options.tx_handle(ports[0],
+                                       (uint16_t)tx_q->txq_id,
+                                       (struct rte_mbuf **)tx_q->m_table,
+                                       (uint16_t)tx_q->len);
+                               if (unlikely(ret < tx_q->len)) {
+                                       do {
+                                               rte_pktmbuf_free(tx_q->m_table[ret]);
+                                       } while (++ret < tx_q->len);
+                               }
+
+                               tx_q->len = 0;
+                       }
+
+                       prev_tsc = cur_tsc;
+
+               }
+
+               rte_prefetch0(lcore_ll->ll_root_used);
+
+               /**
+                * Inform the configuration core that we have exited
+                * the linked list and that no devices are
+                * in use if requested.
+                */
+               if (lcore_ll->dev_removal_flag == REQUEST_DEV_REMOVAL)
+                       lcore_ll->dev_removal_flag = ACK_DEV_REMOVAL;
+
+               /*
+                * Process devices
+                */
+               dev_ll = lcore_ll->ll_root_used;
+
+               while (dev_ll != NULL) {
+                       vdev = dev_ll->vdev;
+                       dev = vdev->dev;
+
+                       if (unlikely(vdev->remove)) {
+                               dev_ll = dev_ll->next;
+                               overlay_options.tunnel_destroy(vdev);
+                               vdev->ready = DEVICE_SAFE_REMOVE;
+                               continue;
+                       }
+                       if (likely(vdev->ready == DEVICE_RX)) {
+                               /* Handle guest RX */
+                               rx_count = rte_eth_rx_burst(ports[0],
+                                       vdev->rx_q, pkts_burst, MAX_PKT_BURST);
+
+                               if (rx_count) {
+                                       /*
+                                       * Retry is enabled and the queue is
+                                       * full then we wait and retry to
+                                       * avoid packet loss. Here MAX_PKT_BURST
+                                       * must be less than virtio queue size
+                                       */
+                                       if (enable_retry && unlikely(rx_count >
+                                               rte_vring_available_entries(dev, VIRTIO_RXQ))) {
+                                               for (retry = 0; retry < burst_rx_retry_num;
+                                                       retry++) {
+                                                       rte_delay_us(burst_rx_delay_time);
+                                                       if (rx_count <= rte_vring_available_entries(dev, VIRTIO_RXQ))
+                                                               break;
+                                               }
+                                       }
+
+                                       ret_count = overlay_options.rx_handle(dev, pkts_burst, rx_count);
+                                       if (enable_stats) {
+                                               rte_atomic64_add(
+                                               &dev_statistics[dev->device_fh].rx_total_atomic,
+                                               rx_count);
+                                               rte_atomic64_add(
+                                               &dev_statistics[dev->device_fh].rx_atomic, ret_count);
+                                       }
+                                       while (likely(rx_count)) {
+                                               rx_count--;
+                                               rte_pktmbuf_free(pkts_burst[rx_count]);
+                                       }
+
+                               }
+                       }
+
+                       if (likely(!vdev->remove)) {
+                               /* Handle guest TX*/
+                               tx_count = rte_vhost_dequeue_burst(dev,
+                                               VIRTIO_TXQ, mbuf_pool,
+                                               pkts_burst, MAX_PKT_BURST);
+                               /* If this is the first received packet we need to learn the MAC */
+                               if (unlikely(vdev->ready == DEVICE_MAC_LEARNING) && tx_count) {
+                                       if (vdev->remove ||
+                                               (overlay_options.tunnel_setup(vdev, pkts_burst[0]) == -1)) {
+                                               while (tx_count)
+                                                       rte_pktmbuf_free(pkts_burst[--tx_count]);
+                                       }
+                               }
+                               while (tx_count)
+                                       virtio_tx_route(vdev, pkts_burst[--tx_count]);
+                       }
+
+                       /* move to the next device in the list */
+                       dev_ll = dev_ll->next;
+               }
+       }
+
+       return 0;
+}
+
+/**
+ * Add an entry to a used linked list. A free entry must first be found
+ * in the free linked list using get_data_ll_free_entry();
+ */
+static void
+add_data_ll_entry(struct virtio_net_data_ll **ll_root_addr,
+       struct virtio_net_data_ll *ll_dev)
+{
+       struct virtio_net_data_ll *ll = *ll_root_addr;
+
+       /* Set next as NULL and use a compiler barrier to avoid reordering. */
+       ll_dev->next = NULL;
+       rte_compiler_barrier();
+
+       /* If ll == NULL then this is the first device. */
+       if (ll) {
+               /* Increment to the tail of the linked list. */
+               while (ll->next != NULL)
+                       ll = ll->next;
+
+               ll->next = ll_dev;
+       } else {
+               *ll_root_addr = ll_dev;
+       }
+}
+
+/**
+ * Remove an entry from a used linked list. The entry must then be added to
+ * the free linked list using put_data_ll_free_entry().
+ */
+static void
+rm_data_ll_entry(struct virtio_net_data_ll **ll_root_addr,
+       struct virtio_net_data_ll *ll_dev,
+       struct virtio_net_data_ll *ll_dev_last)
+{
+       struct virtio_net_data_ll *ll = *ll_root_addr;
+
+       if (unlikely((ll == NULL) || (ll_dev == NULL)))
+               return;
+
+       if (ll_dev == ll)
+               *ll_root_addr = ll_dev->next;
+       else
+               if (likely(ll_dev_last != NULL))
+                       ll_dev_last->next = ll_dev->next;
+               else
+                       RTE_LOG(ERR, VHOST_CONFIG,
+                               "Remove entry form ll failed.\n");
+}
+
+/**
+ * Find and return an entry from the free linked list.
+ */
+static struct virtio_net_data_ll *
+get_data_ll_free_entry(struct virtio_net_data_ll **ll_root_addr)
+{
+       struct virtio_net_data_ll *ll_free = *ll_root_addr;
+       struct virtio_net_data_ll *ll_dev;
+
+       if (ll_free == NULL)
+               return NULL;
+
+       ll_dev = ll_free;
+       *ll_root_addr = ll_free->next;
+
+       return ll_dev;
+}
+
+/**
+ * Place an entry back on to the free linked list.
+ */
+static void
+put_data_ll_free_entry(struct virtio_net_data_ll **ll_root_addr,
+       struct virtio_net_data_ll *ll_dev)
+{
+       struct virtio_net_data_ll *ll_free = *ll_root_addr;
+
+       if (ll_dev == NULL)
+               return;
+
+       ll_dev->next = ll_free;
+       *ll_root_addr = ll_dev;
+}
+
+/**
+ * Creates a linked list of a given size.
+ */
+static struct virtio_net_data_ll *
+alloc_data_ll(uint32_t size)
+{
+       struct virtio_net_data_ll *ll_new;
+       uint32_t i;
+
+       /* Malloc and then chain the linked list. */
+       ll_new = malloc(size * sizeof(struct virtio_net_data_ll));
+       if (ll_new == NULL) {
+               RTE_LOG(ERR, VHOST_CONFIG,
+                       "Failed to allocate memory for ll_new.\n");
+               return NULL;
+       }
+
+       for (i = 0; i < size - 1; i++) {
+               ll_new[i].vdev = NULL;
+               ll_new[i].next = &ll_new[i+1];
+       }
+       ll_new[i].next = NULL;
+
+       return ll_new;
+}
+
+/**
+ * Create the main linked list along with each individual cores
+ * linked list. A used and a free list are created to manage entries.
+ */
+static int
+init_data_ll(void)
+{
+       int lcore;
+
+       RTE_LCORE_FOREACH_SLAVE(lcore) {
+               lcore_info[lcore].lcore_ll =
+                       malloc(sizeof(struct lcore_ll_info));
+               if (lcore_info[lcore].lcore_ll == NULL) {
+                       RTE_LOG(ERR, VHOST_CONFIG,
+                               "Failed to allocate memory for lcore_ll.\n");
+                       return -1;
+               }
+
+               lcore_info[lcore].lcore_ll->device_num = 0;
+               lcore_info[lcore].lcore_ll->dev_removal_flag = ACK_DEV_REMOVAL;
+               lcore_info[lcore].lcore_ll->ll_root_used = NULL;
+               if (nb_devices % nb_switching_cores)
+                       lcore_info[lcore].lcore_ll->ll_root_free =
+                               alloc_data_ll((nb_devices / nb_switching_cores)
+                                               + 1);
+               else
+                       lcore_info[lcore].lcore_ll->ll_root_free =
+                               alloc_data_ll(nb_devices / nb_switching_cores);
+       }
+
+       /* Allocate devices up to a maximum of MAX_DEVICES. */
+       ll_root_free = alloc_data_ll(MIN((nb_devices), MAX_DEVICES));
+
+       return 0;
+}
+
+/**
+ * Remove a device from the specific data core linked list and
+ * from the main linked list. Synchonization occurs through the use
+ * of the lcore dev_removal_flag. Device is made volatile here
+ * to avoid re-ordering of dev->remove=1 which can cause an infinite
+ * loop in the rte_pause loop.
+ */
+static void
+destroy_device(volatile struct virtio_net *dev)
+{
+       struct virtio_net_data_ll *ll_lcore_dev_cur;
+       struct virtio_net_data_ll *ll_main_dev_cur;
+       struct virtio_net_data_ll *ll_lcore_dev_last = NULL;
+       struct virtio_net_data_ll *ll_main_dev_last = NULL;
+       struct vhost_dev *vdev;
+       int lcore;
+
+       dev->flags &= ~VIRTIO_DEV_RUNNING;
+
+       vdev = (struct vhost_dev *)dev->priv;
+
+       /* set the remove flag. */
+       vdev->remove = 1;
+       while (vdev->ready != DEVICE_SAFE_REMOVE)
+               rte_pause();
+
+       /* Search for entry to be removed from lcore ll */
+       ll_lcore_dev_cur = lcore_info[vdev->coreid].lcore_ll->ll_root_used;
+       while (ll_lcore_dev_cur != NULL) {
+               if (ll_lcore_dev_cur->vdev == vdev) {
+                       break;
+               } else {
+                       ll_lcore_dev_last = ll_lcore_dev_cur;
+                       ll_lcore_dev_cur = ll_lcore_dev_cur->next;
+               }
+       }
+
+       if (ll_lcore_dev_cur == NULL) {
+               RTE_LOG(ERR, VHOST_CONFIG,
+                       "(%"PRIu64") Failed to find the dev to be destroy.\n",
+                       dev->device_fh);
+               return;
+       }
+
+       /* Search for entry to be removed from main ll */
+       ll_main_dev_cur = ll_root_used;
+       ll_main_dev_last = NULL;
+       while (ll_main_dev_cur != NULL) {
+               if (ll_main_dev_cur->vdev == vdev) {
+                       break;
+               } else {
+                       ll_main_dev_last = ll_main_dev_cur;
+                       ll_main_dev_cur = ll_main_dev_cur->next;
+               }
+       }
+
+       /* Remove entries from the lcore and main ll. */
+       rm_data_ll_entry(&lcore_info[vdev->coreid].lcore_ll->ll_root_used,
+                       ll_lcore_dev_cur, ll_lcore_dev_last);
+       rm_data_ll_entry(&ll_root_used, ll_main_dev_cur, ll_main_dev_last);
+
+       /* Set the dev_removal_flag on each lcore. */
+       RTE_LCORE_FOREACH_SLAVE(lcore) {
+               lcore_info[lcore].lcore_ll->dev_removal_flag =
+                       REQUEST_DEV_REMOVAL;
+       }
+
+       /*
+        * Once each core has set the dev_removal_flag to
+        * ACK_DEV_REMOVAL we can be sure that they can no longer access
+        * the device removed from the linked lists and that the devices
+        * are no longer in use.
+        */
+       RTE_LCORE_FOREACH_SLAVE(lcore) {
+               while (lcore_info[lcore].lcore_ll->dev_removal_flag
+                       != ACK_DEV_REMOVAL)
+                       rte_pause();
+       }
+
+       /* Add the entries back to the lcore and main free ll.*/
+       put_data_ll_free_entry(&lcore_info[vdev->coreid].lcore_ll->ll_root_free,
+                               ll_lcore_dev_cur);
+       put_data_ll_free_entry(&ll_root_free, ll_main_dev_cur);
+
+       /* Decrement number of device on the lcore. */
+       lcore_info[vdev->coreid].lcore_ll->device_num--;
+
+       RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Device has been removed "
+               "from data core\n", dev->device_fh);
+
+       rte_free(vdev);
+
+}
+
+/**
+ * A new device is added to a data core. First the device is added
+ * to the main linked list and the allocated to a specific data core.
+ */
+static int
+new_device(struct virtio_net *dev)
+{
+       struct virtio_net_data_ll *ll_dev;
+       int lcore, core_add = 0;
+       uint32_t device_num_min = nb_devices;
+       struct vhost_dev *vdev;
+
+       vdev = rte_zmalloc("vhost device", sizeof(*vdev), RTE_CACHE_LINE_SIZE);
+       if (vdev == NULL) {
+               RTE_LOG(INFO, VHOST_DATA,
+                       "(%"PRIu64") Couldn't allocate memory for vhost dev\n",
+                       dev->device_fh);
+               return -1;
+       }
+       vdev->dev = dev;
+       dev->priv = vdev;
+       /* Add device to main ll */
+       ll_dev = get_data_ll_free_entry(&ll_root_free);
+       if (ll_dev == NULL) {
+               RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") No free entry found in"
+                       " linked list Device limit of %d devices per core"
+                       " has been reached\n", dev->device_fh, nb_devices);
+               if (vdev->regions_hpa)
+                       rte_free(vdev->regions_hpa);
+               rte_free(vdev);
+               return -1;
+       }
+       ll_dev->vdev = vdev;
+       add_data_ll_entry(&ll_root_used, ll_dev);
+       vdev->rx_q = dev->device_fh;
+
+       /* reset ready flag */
+       vdev->ready = DEVICE_MAC_LEARNING;
+       vdev->remove = 0;
+
+       /* Find a suitable lcore to add the device. */
+       RTE_LCORE_FOREACH_SLAVE(lcore) {
+               if (lcore_info[lcore].lcore_ll->device_num < device_num_min) {
+                       device_num_min = lcore_info[lcore].lcore_ll->device_num;
+                       core_add = lcore;
+               }
+       }
+       /* Add device to lcore ll */
+       ll_dev = get_data_ll_free_entry(&lcore_info[core_add].lcore_ll->ll_root_free);
+       if (ll_dev == NULL) {
+               RTE_LOG(INFO, VHOST_DATA,
+                       "(%"PRIu64") Failed to add device to data core\n",
+                       dev->device_fh);
+               vdev->ready = DEVICE_SAFE_REMOVE;
+               destroy_device(dev);
+               rte_free(vdev->regions_hpa);
+               rte_free(vdev);
+               return -1;
+       }
+       ll_dev->vdev = vdev;
+       vdev->coreid = core_add;
+
+       add_data_ll_entry(&lcore_info[vdev->coreid].lcore_ll->ll_root_used,
+                       ll_dev);
+
+       /* Initialize device stats */
+       memset(&dev_statistics[dev->device_fh], 0,
+               sizeof(struct device_statistics));
+
+       /* Disable notifications. */
+       rte_vhost_enable_guest_notification(dev, VIRTIO_RXQ, 0);
+       rte_vhost_enable_guest_notification(dev, VIRTIO_TXQ, 0);
+       lcore_info[vdev->coreid].lcore_ll->device_num++;
+       dev->flags |= VIRTIO_DEV_RUNNING;
+
+       RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Device has been added to data core %d\n",
+               dev->device_fh, vdev->coreid);
+
+       return 0;
+}
+
+/**
+ * These callback allow devices to be added to the data core when configuration
+ * has been fully complete.
+ */
+static const struct virtio_net_device_ops virtio_net_device_ops = {
+       .new_device =  new_device,
+       .destroy_device = destroy_device,
+};
+
+/**
+ * This is a thread will wake up after a period to print stats if the user has
+ * enabled them.
+ */
+static void
+print_stats(void)
+{
+       struct virtio_net_data_ll *dev_ll;
+       uint64_t tx_dropped, rx_dropped;
+       uint64_t tx, tx_total, rx, rx_total, rx_ip_csum, rx_l4_csum;
+       uint32_t device_fh;
+       const char clr[] = { 27, '[', '2', 'J', '\0' };
+       const char top_left[] = { 27, '[', '1', ';', '1', 'H', '\0' };
+
+       while (1) {
+               sleep(enable_stats);
+
+               /* Clear screen and move to top left */
+               printf("%s%s", clr, top_left);
+
+               printf("\nDevice statistics ================================");
+
+               dev_ll = ll_root_used;
+               while (dev_ll != NULL) {
+                       device_fh = (uint32_t)dev_ll->vdev->dev->device_fh;
+                       tx_total = dev_statistics[device_fh].tx_total;
+                       tx = dev_statistics[device_fh].tx;
+                       tx_dropped = tx_total - tx;
+
+                       rx_total = rte_atomic64_read(
+                               &dev_statistics[device_fh].rx_total_atomic);
+                       rx = rte_atomic64_read(
+                               &dev_statistics[device_fh].rx_atomic);
+                       rx_dropped = rx_total - rx;
+                       rx_ip_csum = rte_atomic64_read(
+                               &dev_statistics[device_fh].rx_bad_ip_csum);
+                       rx_l4_csum = rte_atomic64_read(
+                               &dev_statistics[device_fh].rx_bad_l4_csum);
+
+                       printf("\nStatistics for device %"PRIu32" ----------"
+                                       "\nTX total:            %"PRIu64""
+                                       "\nTX dropped:          %"PRIu64""
+                                       "\nTX successful:               %"PRIu64""
+                                       "\nRX total:            %"PRIu64""
+                                       "\nRX bad IP csum:      %"PRIu64""
+                                       "\nRX bad L4 csum:      %"PRIu64""
+                                       "\nRX dropped:          %"PRIu64""
+                                       "\nRX successful:               %"PRIu64"",
+                                       device_fh,
+                                       tx_total,
+                                       tx_dropped,
+                                       tx,
+                                       rx_total,
+                                       rx_ip_csum,
+                                       rx_l4_csum,
+                                       rx_dropped,
+                                       rx);
+
+                       dev_ll = dev_ll->next;
+               }
+               printf("\n================================================\n");
+       }
+}
+
+/**
+ * Main function, does initialisation and calls the per-lcore functions. The CUSE
+ * device is also registered here to handle the IOCTLs.
+ */
+int
+main(int argc, char *argv[])
+{
+       struct rte_mempool *mbuf_pool = NULL;
+       unsigned lcore_id, core_id = 0;
+       unsigned nb_ports, valid_nb_ports;
+       int ret;
+       uint8_t portid;
+       uint16_t queue_id;
+       static pthread_t tid;
+       char thread_name[RTE_MAX_THREAD_NAME_LEN];
+
+       /* init EAL */
+       ret = rte_eal_init(argc, argv);
+       if (ret < 0)
+               rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
+       argc -= ret;
+       argv += ret;
+
+       /* parse app arguments */
+       ret = tep_termination_parse_args(argc, argv);
+       if (ret < 0)
+               rte_exit(EXIT_FAILURE, "Invalid argument\n");
+
+       for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++)
+               if (rte_lcore_is_enabled(lcore_id))
+                       lcore_ids[core_id++] = lcore_id;
+
+       /* set the number of swithcing cores available */
+       nb_switching_cores = rte_lcore_count()-1;
+
+       /* Get the number of physical ports. */
+       nb_ports = rte_eth_dev_count();
+       if (nb_ports > RTE_MAX_ETHPORTS)
+               nb_ports = RTE_MAX_ETHPORTS;
+
+       /*
+        * Update the global var NB_PORTS and global array PORTS
+        * and get value of var VALID_NB_PORTS according to system ports number
+        */
+       valid_nb_ports = check_ports_num(nb_ports);
+
+       if ((valid_nb_ports == 0) || (valid_nb_ports > MAX_SUP_PORTS)) {
+               rte_exit(EXIT_FAILURE, "Current enabled port number is %u,"
+                       "but only %u port can be enabled\n", nb_ports,
+                       MAX_SUP_PORTS);
+       }
+       /* Create the mbuf pool. */
+       mbuf_pool = rte_mempool_create(
+                       "MBUF_POOL",
+                       NUM_MBUFS_PER_PORT
+                       * valid_nb_ports,
+                       MBUF_SIZE, MBUF_CACHE_SIZE,
+                       sizeof(struct rte_pktmbuf_pool_private),
+                       rte_pktmbuf_pool_init, NULL,
+                       rte_pktmbuf_init, NULL,
+                       rte_socket_id(), 0);
+       if (mbuf_pool == NULL)
+               rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
+
+       for (queue_id = 0; queue_id < MAX_QUEUES + 1; queue_id++)
+               vpool_array[queue_id].pool = mbuf_pool;
+
+       /* Set log level. */
+       rte_set_log_level(LOG_LEVEL);
+
+       /* initialize all ports */
+       for (portid = 0; portid < nb_ports; portid++) {
+               /* skip ports that are not enabled */
+               if ((enabled_port_mask & (1 << portid)) == 0) {
+                       RTE_LOG(INFO, VHOST_PORT,
+                               "Skipping disabled port %d\n", portid);
+                       continue;
+               }
+               if (overlay_options.port_configure(portid, mbuf_pool) != 0)
+                       rte_exit(EXIT_FAILURE,
+                               "Cannot initialize network ports\n");
+       }
+
+       /* Initialise all linked lists. */
+       if (init_data_ll() == -1)
+               rte_exit(EXIT_FAILURE, "Failed to initialize linked list\n");
+
+       /* Initialize device stats */
+       memset(&dev_statistics, 0, sizeof(dev_statistics));
+
+       /* Enable stats if the user option is set. */
+       if (enable_stats) {
+               ret = pthread_create(&tid, NULL, (void *)print_stats, NULL);
+               if (ret != 0)
+                       rte_exit(EXIT_FAILURE, "Cannot create print-stats thread\n");
+               snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN, "print-stats");
+               ret = rte_thread_setname(tid, thread_name);
+               if (ret != 0)
+                       RTE_LOG(ERR, VHOST_CONFIG, "Cannot set print-stats name\n");
+       }
+
+       /* Launch all data cores. */
+       RTE_LCORE_FOREACH_SLAVE(lcore_id) {
+               rte_eal_remote_launch(switch_worker,
+                       mbuf_pool, lcore_id);
+       }
+       rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_MRG_RXBUF);
+
+       /* Register CUSE device to handle IOCTLs. */
+       ret = rte_vhost_driver_register((char *)&dev_basename);
+       if (ret != 0)
+               rte_exit(EXIT_FAILURE, "CUSE device setup failure.\n");
+
+       rte_vhost_driver_callback_register(&virtio_net_device_ops);
+
+       /* Start CUSE session. */
+       rte_vhost_driver_session_start();
+
+       return 0;
+}