在winpcap中构建udp报文数据包,并且发送数据,使用c++编写有个示例

WinPCAP是一个强大的网络包捕获和分析工具，它允许你在Windows上创建和发送UDP数据包。在C++中，我们可以利用WinPcap库来完成这个任务。以下是一个简单的示例，展示了如何发送UDP数据包：

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

// UDP头部结构体
struct udphdr {
    u_int16_t uh_sport; // 源端口
    u_int16_t uh_dport; // 目标端口
    u_int32_t uh_ulen;  // 数据长度，包括头部
    u_int16_t uh_sum;   // 校验和，一般我们不用设置
};

int main() {
    char errbuf[PCAP_ERRBUF_SIZE]; // 错误信息缓冲区

    // 打开网络设备或抓包接口
    pcap_t* handle = pcap_open_live("eth0", 65536, 1, 1000, errbuf);
    if (handle == NULL) {
        printf("Error opening device: %s\n", errbuf);
        return -1;
    }

    // 创建套接字
    int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (sock < 0) {
        perror("Failed to create socket");
        pcap_close(handle);
        return -1;
    }

    // 设置源和目标IP及端口
    struct sockaddr_in source, dest;
    memset(&source, 0, sizeof(source));
    source.sin_family = AF_INET;
    source.sin_port = htons(1234); // 源端口
    inet_aton("192.168.1.1", &source.sin_addr);

    memset(&dest, 0, sizeof(dest));
    dest.sin_family = AF_INET;
    dest.sin_port = htons(5678); // 目标端口
    inet_aton("192.168.1.2", &dest.sin_addr);

    // 创建UDP头部
    udphdr udp_header;
    udp_header.uh_sport = htons(source.sin_port);
    udp_header.uh_dport = htons(dest.sin_port);
    udp_header.uh_ulen = htons(sizeof(struct udphdr) + strlen("Hello, UDP!")); // 包含头部和数据长度

    // 构造完整的数据包
    char* packet = (char*)malloc(sizeof(struct udphdr) + strlen("Hello, UDP!") + sizeof(source.sin_family) + sizeof(source.sin_addr.s_addr) + sizeof(dest.sin_family) + sizeof(dest.sin_addr.s_addr));
    memcpy(packet, (void*)&udp_header, sizeof(udphdr));
    memcpy(packet + sizeof(udp_header), (void*)&source.sin_family, sizeof(source.sin_family));
    memcpy(packet + sizeof(udp_header) + sizeof(source.sin_family), (void*)&source.sin_addr.s_addr, sizeof(source.sin_addr.s_addr));
    memcpy(packet + sizeof(udp_header) + sizeof(source.sin_family) + sizeof(source.sin_addr.s_addr), (void*)&dest.sin_family, sizeof(dest.sin_family));
    memcpy(packet + sizeof(udp_header) + sizeof(source.sin_family) + sizeof(source.sin_addr.s_addr) + sizeof(dest.sin_family), (void*)&dest.sin_addr.s_addr, sizeof(dest.sin_addr.s_addr));
    memcpy(packet + sizeof(udp_header) + sizeof(source.sin_family) + sizeof(source.sin_addr.s_addr) + sizeof(dest.sin_family) + sizeof(dest.sin_addr.s_addr), "Hello, UDP!", strlen("Hello, UDP!"));

    // 发送数据包
    sendto(sock, packet, sizeof(packet), 0, (struct sockaddr*)&dest, sizeof(dest));
    free(packet);

    // 关闭套接字和设备
    close(sock);
    pcap_close(handle);
    
    printf("UDP packet sent successfully.\n");

    return 0;
}