生成一个pf_ring的接收组播的代码

以下是一个使用PF_RING接收组播数据包的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <time.h>

#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <pfring.h>

#define BUFFER_SIZE 65536

int stop = 0;

void sigproc(int sig) {
    stop = 1;
}

int main(int argc, char **argv) {
    pfring *handle;
    struct pfring_pkthdr hdr;
    const u_char *packet;
    char errbuf[PCAP_ERRBUF_SIZE];
    struct sockaddr_in saddr;
    int sock, sockopt, socklen, sockoptlen;
    char buffer[BUFFER_SIZE];

    if (argc != 2) {
        printf("Usage: %s <multicast address>\n", argv[0]);
        return -1;
    }

    // 创建PF_RING句柄
    handle = pfring_open(argv[1], BUFFER_SIZE, PF_RING_PROMISC);
    if (!handle) {
        printf("Failed to open PF_RING handle: %s\n", strerror(errno));
        return -1;
    }

    // 设置接收组播数据包
    if (pfring_set_direction(handle, rx_only_direction) < 0) {
        printf("Failed to set RX direction: %s\n", strerror(errno));
        pfring_close(handle);
        return -1;
    }

    // 绑定到网络接口
    if (pfring_enable_multicast(handle) < 0) {
        printf("Failed to enable multicast: %s\n", strerror(errno));
        pfring_close(handle);
        return -1;
    }

    // 创建UDP套接字
    sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (sock < 0) {
        printf("Failed to create socket: %s\n", strerror(errno));
        pfring_close(handle);
        return -1;
    }

    // 设置套接字选项
    sockopt = 1;
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &sockopt, sizeof(sockopt)) < 0) {
        printf("Failed to set SO_REUSEADDR: %s\n", strerror(errno));
        close(sock);
        pfring_close(handle);
        return -1;
    }

    // 绑定到本地地址和端口
    memset(&saddr, 0, sizeof(saddr));
    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = INADDR_ANY;
    saddr.sin_port = htons(0);
    if (bind(sock, (struct sockaddr *)&saddr, sizeof(saddr)) < 0) {
        printf("Failed to bind to local address: %s\n", strerror(errno));
        close(sock);
        pfring_close(handle);
        return -1;
    }

    // 加入组播组
    memset(&saddr, 0, sizeof(saddr));
    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = inet_addr(argv[1]);
    socklen = sizeof(saddr);
    if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &saddr, socklen) < 0) {
        printf("Failed to join multicast group: %s\n", strerror(errno));
        close(sock);
        pfring_close(handle);
        return -1;
    }

    // 循环接收数据包
    signal(SIGINT, sigproc);
    while (!stop) {
        packet = pfring_recv(handle, &hdr);
        if (packet) {
            // 处理接收到的数据包
            if (hdr.len > BUFFER_SIZE) {
                printf("Packet too large: %d bytes\n", hdr.len);
            } else {
                memcpy(buffer, packet, hdr.len);
                if (sendto(sock, buffer, hdr.len, 0, (struct sockaddr *)&saddr, socklen) < 0) {
                    printf("Failed to send packet: %s\n", strerror(errno));
                }
            }
            pfring_free_packet(handle, packet);
        }
    }

    // 退出程序
    close(sock);
    pfring_close(handle);
    return 0;
}

这个程序使用PF_RING接收组播数据包，并将其转发到一个本地的UDP套接字。你可以使用类似以下命令来运行它：

$ sudo ./recv_multicast 239.0.0.1

其中`239.0.0.1`是你要接收的组播地址。请注意，你需要以root权限运行该程序。