examples/tep_termination/main.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2015 Intel Corporation
 */

#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_vhost.h>
#include <rte_pause.h>

#include "main.h"
#include "vxlan.h"
#include "vxlan_setup.h"

/* the maximum number of external ports supported */
#define MAX_SUP_PORTS 1

#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_DATA_SIZE RTE_MBUF_DEFAULT_BUF_SIZE

#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

/* 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 0xFFFF

/* 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];
uint16_t ports[RTE_MAX_ETHPORTS];

static unsigned nb_ports; 
/* ethernet addresses of ports */
struct rte_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;

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];

static int
us_vhost_parse_basename(const char *q_arg)
{
    /* parse number string */
    if (strlen(q_arg) >= MAX_BASENAME_SZ)
        return -1;
    else
        strlcpy((char *)&dev_basename, q_arg, MAX_BASENAME_SZ);

    return 0;
}

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;
}

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;
}

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);
}

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;
}

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 (!rte_eth_dev_is_valid_port(ports[portid])) {
            RTE_LOG(INFO, VHOST_PORT,
                "\nSpecified port ID(%u) is not valid\n",
                ports[portid]);
            ports[portid] = INVALID_PORT_ID;
            valid_nb_ports--;
        }
    }
    return valid_nb_ports;
}

static __rte_always_inline void
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();

    RTE_LOG_DP(DEBUG, VHOST_DATA, "(%d) TX: MAC address is external\n",
        vdev->vid);

    /* 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[vdev->vid].tx_total++;
        dev_statistics[vdev->vid].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;
}

static int
switch_worker(__rte_unused void *arg)
{
    struct rte_mempool *mbuf_pool = arg;
    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) {
                RTE_LOG_DP(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);

        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;

            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_vhost_avail_entries(vdev->vid, VIRTIO_RXQ))) {
                        for (retry = 0; retry < burst_rx_retry_num;
                            retry++) {
                            rte_delay_us(burst_rx_delay_time);
                            if (rx_count <= rte_vhost_avail_entries(vdev->vid, VIRTIO_RXQ))
                                break;
                        }
                    }

                    ret_count = overlay_options.rx_handle(vdev->vid, pkts_burst, rx_count);
                    if (enable_stats) {
                        rte_atomic64_add(
                        &dev_statistics[vdev->vid].rx_total_atomic,
                        rx_count);
                        rte_atomic64_add(
                        &dev_statistics[vdev->vid].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(vdev->vid,
                        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;
}

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;
    }
}

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");
}

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;
}

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;
}

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;
}

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;
}

static void
destroy_device(int vid)
{
    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 = NULL;
    int lcore;

    ll_main_dev_cur = ll_root_used;
    while (ll_main_dev_cur != NULL) {
        if (ll_main_dev_cur->vdev->vid == vid) {
            vdev = ll_main_dev_cur->vdev;
            break;
        }
    }
    if (!vdev)
        return;

    /* 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,
            "(%d) Failed to find the dev to be destroy.\n", vid);
        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, "(%d) Device has been removed "
        "from data core\n", vid);

    rte_free(vdev);

}

static int
new_device(int vid)
{
    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,
            "(%d) Couldn't allocate memory for vhost dev\n", vid);
        return -1;
    }
    vdev->vid = vid;
    /* Add device to main ll */
    ll_dev = get_data_ll_free_entry(&ll_root_free);
    if (ll_dev == NULL) {
        RTE_LOG(INFO, VHOST_DATA, "(%d) No free entry found in"
            " linked list Device limit of %d devices per core"
            " has been reached\n", vid, 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 = vid;

    /* 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,
            "(%d) Failed to add device to data core\n",
            vid);
        vdev->ready = DEVICE_SAFE_REMOVE;
        destroy_device(vid);
        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[vid], 0,
        sizeof(struct device_statistics));

    /* Disable notifications. */
    rte_vhost_enable_guest_notification(vid, VIRTIO_RXQ, 0);
    rte_vhost_enable_guest_notification(vid, VIRTIO_TXQ, 0);
    lcore_info[vdev->coreid].lcore_ll->device_num++;

    RTE_LOG(INFO, VHOST_DATA, "(%d) Device has been added to data core %d\n",
        vid, vdev->coreid);

    return 0;
}

static const struct vhost_device_ops virtio_net_device_ops = {
    .new_device =  new_device,
    .destroy_device = destroy_device,
};

static void *
print_stats(__rte_unused void *arg)
{
    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;
    int vid;
    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) {
            vid = dev_ll->vdev->vid;
            tx_total = dev_statistics[vid].tx_total;
            tx = dev_statistics[vid].tx;
            tx_dropped = tx_total - tx;

            rx_total = rte_atomic64_read(
                &dev_statistics[vid].rx_total_atomic);
            rx = rte_atomic64_read(
                &dev_statistics[vid].rx_atomic);
            rx_dropped = rx_total - rx;
            rx_ip_csum = rte_atomic64_read(
                &dev_statistics[vid].rx_bad_ip_csum);
            rx_l4_csum = rte_atomic64_read(
                &dev_statistics[vid].rx_bad_l4_csum);

            printf("\nStatistics for device %d ----------"
                    "\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"",
                    vid,
                    tx_total,
                    tx_dropped,
                    tx,
                    rx_total,
                    rx_ip_csum,
                    rx_l4_csum,
                    rx_dropped,
                    rx);

            dev_ll = dev_ll->next;
        }
        printf("\n================================================\n");

        fflush(stdout);
    }

    return NULL;
}

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;
    uint16_t portid;
    uint16_t queue_id;
    static pthread_t tid;

    /* 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_avail();

    /*
     * 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_pktmbuf_pool_create(
            "MBUF_POOL",
            NUM_MBUFS_PER_PORT * valid_nb_ports,
            MBUF_CACHE_SIZE,
            0,
            MBUF_DATA_SIZE,
            rte_socket_id());
    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;

    /* initialize all ports */
    RTE_ETH_FOREACH_DEV(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 = rte_ctrl_thread_create(&tid, "print-stats", NULL,
                    print_stats, NULL);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Cannot create print-stats thread\n");
    }

    /* Launch all data cores. */
    RTE_LCORE_FOREACH_SLAVE(lcore_id) {
        rte_eal_remote_launch(switch_worker,
            mbuf_pool, lcore_id);
    }

    ret = rte_vhost_driver_register((char *)&dev_basename, 0);
    if (ret != 0)
        rte_exit(EXIT_FAILURE, "failed to register vhost driver.\n");

    rte_vhost_driver_disable_features(dev_basename,
        1ULL << VIRTIO_NET_F_MRG_RXBUF);

    ret = rte_vhost_driver_callback_register(dev_basename,
        &virtio_net_device_ops);
    if (ret != 0) {
        rte_exit(EXIT_FAILURE,
            "failed to register vhost driver callbacks.\n");
    }

    if (rte_vhost_driver_start(dev_basename) < 0) {
        rte_exit(EXIT_FAILURE,
            "failed to start vhost driver.\n");
    }

    RTE_LCORE_FOREACH_SLAVE(lcore_id)
        rte_eal_wait_lcore(lcore_id);

    return 0;
}