写一段通过vhost-user-sock读取数据包的dpdk代码-DPDK中文网

以下是一个简单的DPDK应用程序，通过vhost-user-sock读取数据包：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_mbuf.h>
#include <rte_vhost.h>

#define MAX_PACKET_SZ 2048
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250

int main(int argc, char **argv)
{
    int ret;
    unsigned int i, portid;
    struct rte_mempool *mbuf_pool;
    struct rte_eth_conf port_conf = {0};
    struct rte_eth_rxconf rx_conf = {0};

    /* Initialize DPDK EAL */
    ret = rte_eal_init(argc, argv);
    if (ret < 0) {
        rte_exit(EXIT_FAILURE, "Error: Failed to initialize DPDK EAL.\n");
    }

    argc -= ret;
    argv += ret;

    /* Create memory pool for mbufs */
    mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", NUM_MBUFS, MBUF_CACHE_SIZE,
                                        0, RTE_MBUF_DEFAULT_BUF_SIZE,
                                        rte_socket_id());
    if (mbuf_pool == NULL) {
        rte_exit(EXIT_FAILURE, "Error: Failed to create mbuf pool.\n");
    }

    /* Initialize vhost-user interface */
    struct sockaddr_un un = {0};
    const char *socket_path = "/tmp/vhost-user.sock";
    int vhost_sock;

    memset(&un, 0, sizeof(struct sockaddr_un));
    un.sun_family = AF_UNIX;
    strncpy(un.sun_path, socket_path, sizeof(un.sun_path) - 1);

    if ((vhost_sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        rte_exit(EXIT_FAILURE, "Error: Failed to create socket for vhost-user.\n");
    }

    if (connect(vhost_sock, (struct sockaddr *)&un, sizeof(struct sockaddr_un)) == -1) {
        rte_exit(EXIT_FAILURE, "Error: Failed to connect to vhost-user socket.\n");
    }

    /* Configure Ethernet port */
    portid = 0;

    ret = rte_eth_dev_configure(portid, 1, 1, &port_conf);
    if (ret < 0) {
        rte_exit(EXIT_FAILURE, "Error: Failed to configure Ethernet port.\n");
    }

    /* Configure RX queue */
    rx_conf.rx_drop_en = 1;

    ret = rte_eth_rx_queue_setup(portid, 0, 128, rte_eth_dev_socket_id(portid), &rx_conf, mbuf_pool);
    if (ret < 0) {
        rte_exit(EXIT_FAILURE, "Error: Failed to configure RX queue.\n");
    }

    /* Start Ethernet port */
    ret = rte_eth_dev_start(portid);
    if (ret < 0) {
        rte_exit(EXIT_FAILURE, "Error: Failed to start Ethernet port.\n");
    }

    /* Main loop */
    struct rte_mbuf *mbufs[MAX_PACKET_SZ];
    unsigned int num_pkts;
    ssize_t recv_len;

    while (1) {
        recv_len = recv(vhost_sock, mbufs, sizeof(mbufs), MSG_WAITALL);
        if (recv_len <= 0) {
            rte_exit(EXIT_FAILURE, "Error: Failed to receive data from vhost-user socket.\n");
        }

        num_pkts = recv_len / sizeof(struct rte_mbuf *);

        for (i = 0; i < num_pkts; i++) {
            ret = rte_eth_tx_burst(portid, 0, &mbufs[i], 1);
            if (ret < 1) {
                rte_pktmbuf_free(mbufs[i]);
            }
        }
    }

    return 0;
}

这个应用程序初始化了DPDK环境以及vhost-user接口，并通过一个无限循环不断从vhost-user socket中读取消息包。它通过rte_eth_dev_configure和rte_eth_rx_queue_setup设置了Ethernet端口的配置，然后启动了该端口（通过rte_eth_dev_start）。在循环中，收到的消息被发送到Ethernet端口（通过rte_eth_tx_burst），并在发送完成之后释放rte_mbuf缓冲区（通过rte_pktmbuf_free）。