从零构建自己的远控•UDP构建socket通信(5)

先用udp构建一个socket通信示例为后面编写iocp服务器做准备

先编写服务器 3步 初始化套接字  绑定端口  收数据

#include <stdio.h>
#include <winsock2.h>
#include <WS2tcpip.h>
#pragma comment(lib,"ws2_32.lib")

int main()
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }
    //1.初始化套接字
    SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    //2.绑定端口
    sockaddr_in addr;
    //转换大小尾
    addr.sin_family = AF_INET;
    addr.sin_port = htons(0x12345);
    inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
    if (bind(s, (sockaddr*)&addr, sizeof(addr)) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }

    //域名转换
    //struct addrinfo hints = { 0 };
    //hints.ai_family = AF_INET;
    //struct addrinfo* resulut = NULL;
    //struct addrinfo* ptr = NULL;
    //if (getaddrinfo("localhost", NULL, &hints, &resulut))
    //{
    //    printf("getaddrinfo error");
    //    return 0;
    //}
    ////是个链表
    //struct sockaddr_in* sockaddr_ipv4;
    ////循环遍历所有ip地址
    //for (ptr = resulut; ptr != NULL; ptr = ptr->ai_next)
    //{
    //    sockaddr_ipv4 = (struct sockaddr_in*)ptr->ai_addr;
    ///*    printf("\tIPv4 address %s\n",
    //        inet_ntoa(sockaddr_ipv4->sin_addr));*/
    //    char szIP[128];
    //    inet_ntop(AF_INET, &sockaddr_ipv4->sin_addr, szIP, sizeof(szIP));
    //    printf("%s", szIP);

    //}
    //3.收发数据
    printf("recvfrom");
    char szBuffer[256];
    sockaddr_in caddr; //客户端地址
    int nLength = sizeof(caddr);
    while (1)
    {
        int nRet=recvfrom(s, szBuffer,sizeof(szBuffer),0,(sockaddr *)&caddr, &nLength);
        if (nRet==SOCKET_ERROR)
        {
            printf("recvfrom error %08X", WSAGetLastError());
            break;
        }
　　　　szBuffer[nRet] = '\0';

        printf("data:%s bytes:%d\n", szBuffer, nRet);
    }
    //关闭初始化
    closesocket(s);
    //反初始化库
    WSACleanup();
}

客户端 2步 初始化套接字 发消息

#include <stdio.h>
#include <winsock2.h>
#include <WS2tcpip.h>
#pragma comment(lib,"ws2_32.lib")


int main()
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }
    //1.初始化套接字
    SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    sockaddr_in addr;
    //转换大小尾
    addr.sin_family = AF_INET;
    addr.sin_port = htons(0x12345);
    inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);

    //2.收发数据
    char szBuffer[256];
    while (1)
    {
        scanf_s("%s", szBuffer, sizeof(szBuffer));
        //发送数据
         sendto(s, szBuffer, strlen(szBuffer), 0, (sockaddr*)&addr, sizeof(addr));
    
    }
    //关闭初始化
    closesocket(s);
    //反初始化库
    WSACleanup();
}

丢包严重。。 

单线程的简单模拟通信， socket 离不开多线程的 不可能只有一个socket结构 后面要把socket 封装成类 为每一个客户端实例化

 这样代码服务端

#include <stdio.h>
#include <winsock2.h>
#include <WS2tcpip.h>
#pragma comment(lib,"ws2_32.lib")

DWORD WINAPI RecvThread(LPVOID lpParameter)//接收消息线程
{
    SOCKET s = (SOCKET)lpParameter;
    char szBuffer[256];
    sockaddr_in caddr; //客户端地址
    int nLength = sizeof(caddr);
    while (1)
    {
        //接收  返回接收长度
        int nRet = recvfrom(s, szBuffer, sizeof(szBuffer), 0, (sockaddr*)&caddr, &nLength);
        if (nRet == SOCKET_ERROR)
        {
            printf("recvfrom error %08X", WSAGetLastError());
            break;
        }
        szBuffer[nRet] = '\0';

        char IPdotdec[20]; //存放点分十进制IP地址
        struct in_addr s; // IPv4地址结构体
        inet_ntop(AF_INET, &caddr.sin_addr, IPdotdec, 16);//点阵转换ip
        printf("ip:%s port:%d  data:%s bytes:%d\n", IPdotdec, caddr.sin_port, szBuffer, nRet);
    }
}

int main()
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }
    //1.初始化套接字
    SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    //2.绑定端口
    sockaddr_in addr;
    //转换大小尾
    addr.sin_family = AF_INET;
    addr.sin_port = htons(0x12345);
    inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
    if (bind(s, (sockaddr*)&addr, sizeof(addr)) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }


    //3.收发数据
    printf("recvfrom、\n");
    CreateThread(NULL, 0, RecvThread, (LPVOID)s, 0, NULL);
    char szBuffer[256];
    sockaddr_in caddr; //客户端地址
    int nLength = sizeof(caddr);
    while (1)
    {
        //接收  返回接收长度
        int nRet = recvfrom(s, szBuffer, sizeof(szBuffer), 0, (sockaddr*)&caddr, &nLength);
        if (nRet == SOCKET_ERROR)
        {
            printf("recvfrom error %08X", WSAGetLastError());
            break;
        }
        szBuffer[nRet] = '\0';
    
        char IPdotdec[20]; //存放点分十进制IP地址
        inet_ntop(AF_INET, &caddr.sin_addr, IPdotdec, 16);//点阵转换ip
        printf("ip:%s port:%d  data:%s bytes:%d\n", IPdotdec, caddr.sin_port, szBuffer, nRet);
        
        sendto(s,"ok", strlen("ok"), 0, (sockaddr*)&caddr, sizeof(caddr));
    }
    //关闭初始化
    closesocket(s);
    //反初始化库
    WSACleanup();
}

代码端

#include <stdio.h>
#include <winsock2.h>
#include <WS2tcpip.h>
#pragma comment(lib,"ws2_32.lib")

DWORD WINAPI RecvThread(LPVOID lpParameter)//接收消息线程
{
    SOCKET s = (SOCKET)lpParameter;
    char szBuffer[256];
    sockaddr_in caddr; //客户端地址
    int nLength = sizeof(caddr);
    while (1)
    {
        //接收  返回接收长度
        int nRet = recvfrom(s, szBuffer, sizeof(szBuffer), 0, (sockaddr*)&caddr, &nLength);
        if (nRet == SOCKET_ERROR)
        {
            printf("recvfrom error %08X", WSAGetLastError());
            break;
        }
        szBuffer[nRet] = '\0';

        char IPdotdec[20]; //存放点分十进制IP地址
        struct in_addr s; // IPv4地址结构体
        inet_ntop(AF_INET, &caddr.sin_addr, IPdotdec, 16);//点阵转换ip
        printf("ip:%s port:%d  data:%s bytes:%d\n", IPdotdec, caddr.sin_port, szBuffer, nRet);
    }    
}

int main()
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("WSAStartup error%08X", WSAGetLastError());
        return 0;
    }
    //1.初始化套接字
    SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    sockaddr_in addr;
    //转换大小尾
    addr.sin_family = AF_INET;
    addr.sin_port = htons(0x12345);
    inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);


    //2.收发数据
    char szBuffer[256];

    int flag = 1;
    while (1)
    {
        scanf_s("%s", szBuffer, sizeof(szBuffer));
　　　　 fflush(stdin);
        //发送数据
         sendto(s, szBuffer, strlen(szBuffer), 0, (sockaddr*)&addr, sizeof(addr));
         //char IPdotdec[20]; //存放点分十进制IP地址
         //inet_ntop(AF_INET, &addr.sin_addr, IPdotdec, 16);
         //printf("ip :%s  port:%d ", IPdotdec, addr.sin_port);

         if (flag)
         {
             CreateThread(NULL, 0, RecvThread, (LPVOID)s, 0, NULL);
             flag = 0;
         }
    }
    //关闭初始化
    closesocket(s);
    //反初始化库
    WSACleanup();
}

标签：sockaddr,UDP,socket,caddr,szBuffer,构建,printf,sin,addr
来源： https://www.cnblogs.com/feizianquan/p/15158535.html