dpdk产生udp报文的api-DPDK中文网

DPDK提供了一些API来生成UDP报文。以下是其中几个常用的API：

rte_pktmbuf_alloc(): 用于分配一个rte_mbuf结构体，该结构体表示一个数据包。
rte_pktmbuf_append(): 用于将数据添加到rte_mbuf中。可以使用此函数添加UDP头和负载数据。
rte_ipv4_udptcp_cksum(): 用于计算IPv4 UDP报文的校验和。
rte_eth_tx_burst(): 将一个或多个rte_mbuf发送到指定的网络接口上。

下面是一个简单的示例代码，它使用DPDK API生成一个带有UDP头和负载数据的UDP报文，并将其发送到指定的网络接口上：

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

#include <rte_common.h>
#include <rte_ethdev.h>
#include <rte_udp.h>

#define MBUF_POOL_SIZE 2048
#define MBUF_CACHE_SIZE 32
#define ETH_PORT_ID 0

int main(int argc, char **argv) {
    int ret;
    struct rte_mempool *mbuf_pool;
    struct rte_eth_dev_info dev_info;
    struct ether_addr dst_mac_addr = { .addr_bytes = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55} };
    struct ether_addr src_mac_addr;
    uint16_t vlan_id = RTE_ETHER_TYPE_VLAN;
    uint32_t src_ip_addr = IPv4(192,168,1,10);
    uint32_t dst_ip_addr = IPv4(192,168,1,20);
    uint16_t src_udp_port = 5000;
    uint16_t dst_udp_port = 6000;
    char payload[] = "Hello World!";
    size_t payload_size = strlen(payload) + 1;

    /* Initialize DPDK */
    ret = rte_eal_init(argc, argv);
    if (ret < 0) {
        rte_exit(EXIT_FAILURE, "Error initializing DPDK\n");
    }

    /* Create a memory pool for mbufs */
    mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", MBUF_POOL_SIZE,
                                        MBUF_CACHE_SIZE, 0, RTE_MBUF_DEFAULT_BUF_SIZE,
                                        rte_socket_id());
    if (mbuf_pool == NULL) {
        rte_exit(EXIT_FAILURE, "Error creating mbuf pool\n");
    }

    /* Get Ethernet device information */
    memset(&dev_info, 0, sizeof(dev_info));
    rte_eth_dev_info_get(ETH_PORT_ID, &dev_info);

   /* Get the MAC address of the Ethernet device */
   rte_eth_macaddr_get(ETH_PORT_ID, &src_mac_addr);

   /* Allocate an mbuf for the UDP packet */
   struct rte_mbuf *pkt_buf = rte_pktmbuf_alloc(mbuf_pool);
   if (pkt_buf == NULL) {
       printf("Failed to allocate mbuf for packet.\n");
       return -1;
   }

   /* Add Ethernet header to packet buffer */
   struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(pkt_buf, struct ether_hdr*);
   eth_hdr->d_addr = dst_mac_addr;
   eth_hdr->s_addr = src_mac_addr;
   eth_hdr->ether_type = htons(RTE_ETHER_TYPE_IPV4);

   /* Add VLAN tag to packet buffer if necessary*/
   if (vlan_id != RTE_ETHER_TYPE_VLAN) {
       struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
       vlan_hdr->vlan_tci = htons(vlan_id);
       vlan_hdr->eth_proto = htons(RTE_ETHER_TYPE_IPV4);
   }

   /* Add IPv4 header to packet buffer */
   struct ipv4_hdr *ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1) + (vlan_id != RTE_ETHER_TYPE_VLAN ? 1 : 0);
   memset(ipv4_hdr, 0, sizeof(*ipv4_hdr));
   ipv4_hdr->version_ihl = IP_VHL_DEF;
   ipv4_hdr->total_length = rte_cpu_to_be_16(sizeof(struct ipv4_hdr) + sizeof(struct udp_hdr) + payload_size);
   ipv4_hdr->src_addr = rte_cpu_to_be_32(src_ip_addr);
   ipv4_hdr->dst_addr = rte_cpu_to_be_32(dst_ip_addr);
   ipv4_hdr->next_proto_id = IPPROTO_UDP;
   ipv4_hdr->time_to_live = IP_DEFTTL;

    /* Add UDP header and payload to packet buffer */
    struct udp_hdr *udp_header =
        (struct udp_hdrr *)(((uint8_t *)ipv4_header) + sizeof(struct ipv4_header));
    memset(udp_header, 0, sizeof(struct udp_hdrr));
    udp_header->src_port = rte_cpu_to_be_16(src_udp_port);
    udp_header->dst_port = rte_cpu_to_be_16(dst_udp_port);
    udp_header->dgram_len =
        rte_cpu_to_be_16(sizeof(struct udp_hdrr) + payload_size);

    char *pkt_data =
        ((char *)udp_header) +
        sizeof(struct udp_hdrr); /* point to the start of the payload */
    memcpy(pkt_data, payload, payload_size);

     /* Calculate UDP checksum */
     udp_header->dgram_cksum = rte_ipv4_udptcp_cksum(ipv4_hdr, udp_header);

    /* Send the packet */
    uint16_t nb_tx = rte_eth_tx_burst(ETH_PORT_ID, 0, &pkt_buf, 1);
    if (nb_tx != 1) {
        printf("Failed to send packet.\n");
        return -1;
    }

    return 0;
}

注意：IPv4宏定义(IPv4())和大端小端转换函数(rte_cpu_to_be_16(),rte_cpu_to_be_32())的定义需要根据具体环境进行修改。