5个dpdk的误区，用代码来解决,从dpdk手写协议栈开始取四个标题-DPDK中文网

误区：DPDK是一个完整的网络协议栈解决方案。解决方案：DPDK本身只提供了数据包处理的基础库，开发者需要自己实现协议栈的其他层级。可以从手写协议栈开始，逐步构建完整的网络协议栈。
误区：DPDK的应用一定要使用hugepage内存。解决方案：虽然使用hugepage内存能够提高性能，但并不是所有应用都需要使用。如果应用程序内存较小，可以考虑使用普通的系统内存。
误区：DPDK只能在特定的硬件上运行。解决方案：DPDK支持多种硬件平台，如x86、ARM等，并且已经被广泛应用于云计算、边缘计算等领域。因此，不存在只能在特定硬件上运行的限制。
误区：DPDK的应用必须使用Linux操作系统。解决方案：DPDK支持多种操作系统，如Linux、FreeBSD、Windows等。因此，在选择操作系统时，应该考虑具体的应用场景和需求。

下面给出从dpdk手写协议栈开始的示例代码：

#include <stdio.h>
#include <stdint.h>
#include <string.h>

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

#define RX_RING_SIZE 128
#define TX_RING_SIZE 512

#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 }
};

static struct rte_mempool *mbuf_pool;

int main(int argc, char *argv[])
{
    int ret;
    uint16_t nb_ports;
    uint16_t portid;
    uint64_t total_packets = 0;
    uint64_t total_bytes = 0;

    /* Initialize EAL */
    ret = rte_eal_init(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error: %s\n", rte_strerror(ret));

    /* Check if there is at least one port available */
    nb_ports = rte_eth_dev_count_avail();
    if (nb_ports == 0)
        rte_exit(EXIT_FAILURE, "Error: No Ethernet ports found.\n");

    /* 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());

    /* Configure each port */
    for (portid = 0; portid < nb_ports; portid++) {
        struct rte_eth_conf port_conf = port_conf_default;
        struct rte_eth_dev_info dev_info;
        uint16_t mtu;

        /* Initialize port */
        ret = rte_eth_dev_configure(portid, 1, 1, &port_conf);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Error: Cannot configure port %u (%d)\n", portid, ret);

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

        /* Set up RX queue */
        ret = rte_eth_rx_queue_setup(portid, 0, RX_RING_SIZE, rte_eth_dev_socket_id(portid), NULL, mbuf_pool);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Error: Cannot set up RX queue for port %u (%d)\n", portid, ret);

        /* Set up TX queue */
        ret = rte_eth_tx_queue_setup(portid, 0, TX_RING_SIZE, rte_eth_dev_socket_id(portid), NULL);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Error: Cannot set up TX queue for port %u (%d)\n", portid, ret);

        /* Set MTU */
        mtu = RTE_MIN(dev_info.max_rx_pktlen, ETHER_MAX_LEN);
        ret = rte_eth_dev_set_mtu(portid, mtu);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Error: Cannot set MTU for port %u (%d)\n", portid, ret);

        /* Start port */
        ret = rte_eth_dev_start(portid);
        if (ret < 0)
            rte_exit(EXIT_FAILURE, "Error: Cannot start port %u (%d)\n", portid, ret);

        printf("Port %u initialized\n", portid);
    }

    /* Main loop */
    while (1) {
        uint16_t nb_rx;
        uint16_t nb_tx;
        uint16_t i;

        /* Receive packets */
        for (portid = 0; portid < nb_ports; portid++) {
            struct rte_mbuf *bufs[BURST_SIZE];

            nb_rx = rte_eth_rx_burst(portid, 0, bufs, BURST_SIZE);
            if (nb_rx > 0) {
                total_packets += nb_rx;
                for (i = 0; i < nb_rx; i++) {
                    total_bytes += bufs[i]->pkt_len;
                    rte_pktmbuf_free(bufs[i]);
                }
            }
        }

        /* Transmit packets */
        for (portid = 0; portid < nb_ports; portid++) {
            struct rte_mbuf *bufs[BURST_SIZE];

            nb_tx = rte_eth_tx_burst(portid, 0, bufs, BURST_SIZE);
            if (nb_tx > 0)
                rte_pktmbuf_free_bulk(bufs, nb_tx);
        }
    }

    return 0;
}