用dpdk写一个网口收包的示例程序。

以下是一个简单的DPDK示例程序，用于网口收包：

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>

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

#define RX_RING_SIZE 128
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
#define BURST_SIZE 32

static const struct rte_eth_conf port_conf_default = {
    .rxmode = {
        .max_rx_pkt_len = ETHER_MAX_LEN,
    },
};

int main(int argc, char *argv[]) {
    int ret;
    uint16_t nb_ports;
    uint16_t portid;
    struct rte_mempool *mbuf_pool;
    struct rte_eth_conf port_conf = port_conf_default;
    struct rte_eth_dev_info dev_info;
    struct rte_eth_rxconf rxq_conf;
    struct rte_eth_dev_tx_buffer *tx_buffer;

    /* Initialize the Environment Abstraction Layer (EAL). */
    ret = rte_eal_init(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");

    argc -= ret;
    argv += ret;

    /* Check that there is at least one port available. */
    nb_ports = rte_eth_dev_count_avail();
    if (nb_ports < 1)
        rte_exit(EXIT_FAILURE, "Error: no ports available\n");

    /* Configure the first Ethernet device. */
    portid = 0;
    ret = rte_eth_dev_configure(portid, 1, 1, &port_conf);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error configuring the Ethernet device\n");

    /* Get the device information. */
    rte_eth_dev_info_get(portid, &dev_info);

    /* Allocate a mbuf pool. */
    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, "Cannot create mbuf pool\n");

    /* Configure the Ethernet device RX queue. */
    rxq_conf = dev_info.default_rxconf;
    rxq_conf.rx_drop_en = 1;
    ret = rte_eth_rx_queue_setup(portid, 0, RX_RING_SIZE,
        rte_eth_dev_socket_id(portid), &rxq_conf, mbuf_pool);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Cannot configure RX queue\n");

    /* Start the Ethernet device. */
    ret = rte_eth_dev_start(portid);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Cannot start Ethernet device\n");

    /* Enable RX in promiscuous mode for the Ethernet device. */
    rte_eth_promiscuous_enable(portid);

    /* Initialize the transmit buffer. */
    tx_buffer = rte_zmalloc_socket("tx_buffer", RTE_ETH_TX_BUFFER_SIZE(BURST_SIZE), 0,
        rte_eth_dev_socket_id(portid));
    if (tx_buffer == NULL)
        rte_exit(EXIT_FAILURE, "Cannot allocate transmit buffer\n");
    rte_eth_tx_buffer_init(tx_buffer, BURST_SIZE);

    /* Receive and transmit packets. */
    struct rte_mbuf *bufs[BURST_SIZE];
    while (true) {
        const uint16_t nb_rx = rte_eth_rx_burst(portid, 0, bufs, BURST_SIZE);
        if (nb_rx == 0)
            continue;
        for (uint16_t i = 0; i < nb_rx; i++) {
            struct rte_mbuf *buf = bufs[i];
            /* Process the packet here. */
            rte_pktmbuf_free(buf);
        }
    }

    return 0;
}

此示例程序初始化EAL、配置和启动第一个以太网设备、创建mbuf池、配置RX队列、启用混杂模式并接收和处理包。可以使用以下命令编译此程序：

$ gcc -o example example.c -I /usr/include/dpdk -L /usr/lib -ldpdk

该程序需要在root权限下运行。