DPDK 实现一个简单的防火墙（基于 L4 规则）-DPDK中文网

使用 DPDK 实现一个简单的防火墙（基于 L4 规则）涉及到处理传入的网络数据包，并根据预设的规则决定是否允许或阻止这些数据包。下面是一个基础示例，展示如何通过 DPDK 创建一个简单的 L4 防火墙，主要关注 TCP 和 UDP 协议。

前提条件

确保您已经安装了 DPDK，并配置了相关环境变量。

示例代码

以下是一个基本的实现示例，演示如何处理数据包并检查源和目的端口。

#include <stdio.h>
#include <stdint.h>
#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_ip.h>
#include <rte_tcp.h>
#include <rte_udp.h>
#include <rte_mbuf.h>

#define NUM_MBUFS 8191
#define MBUF_SIZE (sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM)
#define ALLOWED_TCP_PORT 80 // Allow traffic on port 80 (HTTP)
#define ALLOWED_UDP_PORT 53 // Allow traffic on port 53 (DNS)

static uint16_t port_id;

static void process_packet(struct rte_mbuf *mbuf) {
    struct ether_hdr *eth_hdr;
    struct ipv4_hdr *ipv4_hdr;

    // Parse Ethernet header
    eth_hdr = rte_pktmbuf_mtod(mbuf, struct ether_hdr *);
    
    if (eth_hdr->ether_type == rte_cpu_to_be_16(ETHER_TYPE_IPv4)) {
        ipv4_hdr = (struct ipv4_hdr *)(eth_hdr + 1);
        
        // Check for TCP or UDP protocol
        if (ipv4_hdr->next_proto_id == IPPROTO_TCP) {
            struct tcp_hdr *tcp_hdr = (struct tcp_hdr *)((uint8_t *)ipv4_hdr + (ipv4_hdr->ihl * 4));
            
            printf("Received TCP packet: src_port=%u dst_port=%u\n",
                   ntohs(tcp_hdr->src_port), ntohs(tcp_hdr->dst_port));
                   
            // 检查是否允许此 TCP 包
            if (ntohs(tcp_hdr->dst_port) != ALLOWED_TCP_PORT) {
                printf("Blocked TCP packet to port %u\n", ntohs(tcp_hdr->dst_port));
                rte_pktmbuf_free(mbuf); // 丢弃数据包
                return;
            }
        } else if (ipv4_hdr->next_proto_id == IPPROTO_UDP) {
            struct udp_hdr *udp_hdr = (struct udp_hdr *)((uint8_t *)ipv4_hdr + (ipv4_hdr->ihl * 4));

            printf("Received UDP packet: src_port=%u dst_port=%u\n",
                   ntohs(udp_hdр.src_port), ntohs(udp_hdр.dst_port));

            // 检查是否允许此 UDP 包
            if (ntohs(udp_hdр.dst_port) != ALLOWED_UDP_PORT) {
                printf("Blocked UDP packet to port %u\n", ntohs(udp_hdр.dst_port));
                rte_pktmbuf_free(mbuf); // 丢弃数据包
                return;
            }
        }

        // 如果符合规则，可以继续转发或处理这个包...
    }

    // Free mbuf after processing
    rte_pktmbuf_free(mbuf);
}

int main(int argc, char **argv) {
    int ret;
    uint16_t nb_rxd = 128; // Number of packets to receive

    ret = rte_eal_init(argc, argv);
    if (ret < 0) {
        fprintf(stderr, "Error with EAL initialization\n");
        return -1;
    }

    port_id = atoi(argv[1]); // Get port ID from command line argument
    
    struct rte_eth_conf port_conf_default = { .rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN }};
    
   ret = rte_eth_dev_configure(port_id, 1, 1, &port_conf_default);
    
   if(ret !=0){
      printf("Failed to configure device\n");
      return -1;
   }
    
   ret = rte_eth_rx_queue_setup(port_id, queue_id, nb_rxd,
                          rte_socket_id(), NULL);

   ret = rte_eth_tx_queue_setup(port_id, queue_id, nb_txd,
                          rte_socket_id(), NULL);

   ret = rte_eth_dev_start(port_id);

   while(1){
       struct rte_mbuf *pkts_burst[BURST_SIZE];
       uint16_t rx_count;

       rx_count = rte_eth_rx_burst(port_id, queue_id, pkts_burst,BURST_SIZE);

       for(uint16_t i=0;i<rx_count;i++){
           process_packet(pkts_burst[i]);
       }
       
   }

   return ret;
}