Windows c语言发送ip广播包

在Windows平台上，可以使用WinPcap或者Npcap库来发送IP广播包。下面是一个简单的示例代码，可以在Visual Studio中编译运行：

#include <stdio.h>
#include <stdlib.h>
#include <pcap.h>
#include <winsock2.h>
#include <iphlpapi.h>

#define MAX_PACKET_SIZE 65535

int main(int argc, char* argv[])
{
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_t* handle;
    struct pcap_pkthdr header;
    const u_char* packet;
    int packet_len;

    // 打开网卡
    handle = pcap_open_live("Ethernet", MAX_PACKET_SIZE, 1, 1000, errbuf);
    if (handle == NULL) {
        fprintf(stderr, "Error opening adapter: %s\n", errbuf);
        return 1;
    }

    // 获取本机IP地址和子网掩码
    ULONG adapter_ip, adapter_mask;
    if (GetAdaptersAddresses(AF_INET, 0, NULL, NULL, NULL) == ERROR_NO_DATA) {
        fprintf(stderr, "Error getting adapter addresses\n");
        return 1;
    }
    PIP_ADAPTER_ADDRESSES adapter_addresses = NULL;
    if (GetAdaptersAddresses(AF_INET, 0, NULL, adapter_addresses, &adapter_mask) == ERROR_BUFFER_OVERFLOW) {
        adapter_addresses = (PIP_ADAPTER_ADDRESSES)malloc(adapter_mask);
        if (adapter_addresses == NULL) {
            fprintf(stderr, "Error allocating memory for adapter addresses\n");
            return 1;
        }
        if (GetAdaptersAddresses(AF_INET, 0, NULL, adapter_addresses, &adapter_mask) != NO_ERROR) {
            fprintf(stderr, "Error getting adapter addresses\n");
            return 1;
        }
    }
    ULONG adapter_index = adapter_addresses->IfIndex;
    adapter_ip = ((PIP_ADAPTER_UNICAST_ADDRESS)adapter_addresses->FirstUnicastAddress)->Address.lpSockaddr->sa_data[2] << 24 |
                 ((PIP_ADAPTER_UNICAST_ADDRESS)adapter_addresses->FirstUnicastAddress)->Address.lpSockaddr->sa_data[3] << 16 |
                 ((PIP_ADAPTER_UNICAST_ADDRESS)adapter_addresses->FirstUnicastAddress)->Address.lpSockaddr->sa_data[4] << 8 |
                 ((PIP_ADAPTER_UNICAST_ADDRESS)adapter_addresses->FirstUnicastAddress)->Address.lpSockaddr->sa_data[5];
    adapter_mask = ((PIP_ADAPTER_UNICAST_ADDRESS)adapter_addresses->FirstUnicastAddress)->OnLinkPrefixLength;
    free(adapter_addresses);

    // 构建IP广播包
    u_char packet_buffer[MAX_PACKET_SIZE];
    packet_len = snprintf(packet_buffer, MAX_PACKET_SIZE, "Destination IP: %d.%d.%d.%d " /* 广播地址 */
                                                        "Source IP: %d.%d.%d.%d " /* 本机IP地址 */
                                                        "Protocol: 17 " /* UDP协议 */
                                                        "Data: Hello, World!",
                          (255 << (32 - adapter_mask)) >> 24, (255 << (32 - adapter_mask)) >> 16, (255 << (32 - adapter_mask)) >> 8, 255,
                          adapter_ip >> 24 & 0xff, adapter_ip >> 16 & 0xff, adapter_ip >> 8 & 0xff, adapter_ip & 0xff);

    // 发送IP广播包
    if (pcap_sendpacket(handle, packet_buffer, packet_len) != 0) {
        fprintf(stderr, "Error sending packet: %s\n", pcap_geterr(handle));
        return 1;
    }

    // 关闭网卡
    pcap_close(handle);
    return 0;
}

需要注意的是，发送IP广播包需要有管理员权限。另外，示例代码中获取本机IP地址和子网掩码需要使用IPHLPAPI库中的API函数，如果需要获取其他信息，可以参考该库中提供的其他函数。