与Wireshark 'dtls‘筛选器等效的WinPcap

#include <pcap.h>

void packet_handler(u_char *user_data, const struct pcap_pkthdr *pkthdr, const u_char *packet) {
    // 这里添加代码来检查数据包是否是 DTLS 数据包
    // 如果是，处理它
}

int main() {
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_t *handle;
    char filter_exp[] = "udp and port 4433"; // DTLS 默认端口是 4433
    struct bpf_program fp;
    bpf_u_int32 mask;
    bpf_u_int32 net;

    // 打开网络设备
    handle = pcap_open_live("eth0", BUFSIZ, 1, 1000, errbuf);
    if (handle == NULL) {
        fprintf(stderr, "Couldn't open device eth0: %s\n", errbuf);
        return 2;
    }

    // 获取网络掩码
    if (pcap_lookupnet("eth0", &net, &mask, errbuf) == -1) {
        fprintf(stderr, "Couldn't get netmask for device eth0: %s\n", errbuf);
        net = 0;
        mask = 0;
    }

    // 编译过滤器
    if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
        fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
        return 2;
    }

    // 应用过滤器
    if (pcap_setfilter(handle, &fp) == -1) {
        fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
        return 2;
    }

    // 开始捕获数据包
    pcap_loop(handle, 0, packet_handler, NULL);

    // 关闭网络设备
    pcap_close(handle);

    return 0;
}