TCPServer TCPClient三次握手模擬編程

套接字創建和關閉：

SOCKET socket(int af,int type,int protocal);

套接字類型：

SOCK_STREAM 流套接字，TCP提供有連接的可靠傳輸

SOCK_DGRAM 數據包套接字，UDP提供無連接的不可靠傳輸

SOCK_RAW 原始套接字

綁定套接字到指定的IP地址和端口號

int bind(
SOCKET s,//套接字句柄
const struct sockaddr * name,//關聯的本地地址
int namelen//地址的長度
);

監聽

int listen(
SOCKET s,//套接字
int backlog//最大連接數
)

連接

int accept(
SOCKET s,
struct sockaddr* addr,//取得對方的地址信息
int* addrlen//指向地址長度
);

int connect(
  SOCKET s,
  const struct sockaddr FAR* name,//連接的地址信息
  int namelen  //結構長度
);

收發數據

int send(
SOCKET s,
const char FAR* buf,//要發送數據的緩沖區地址
int len,//緩沖區長度
int flags//指定調用方式，通常為0
);
int recv(
SOCKET s,
char FAR* buf,
int len,
int
);

 

TCPSERVER端代碼：

// TCP.cpp : 定義控制台應用程序的入口點。
//

#include "stdafx.h"
#include <winsock2.h>
#include <stdio.h>

#pragma comment(lib,"WS2_32")
class CInitSock
{
public:
    CInitSock(BYTE minorVer=2,BYTE majorVer=2)
    {
        WSADATA wsaData;
        WORD sockVersion = MAKEWORD(minorVer,majorVer);
        if(::WSAStartup(sockVersion,&wsaData)!=0)
        {
            exit(0);
        }
    }
    ~CInitSock()
    {
        ::WSACleanup();
    }
};
CInitSock initSock;
int _tmain(int argc, _TCHAR* argv[])
{
    SOCKET sListen = ::socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(sListen == INVALID_SOCKET)
    {
        printf("Failed socket()\n");
        return 0;
    }
    //填充sockaddr_in結構
    sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(4567);
    sin.sin_addr.S_un.S_addr = INADDR_ANY;
    //綁定這個套接字的一個本地地址
    if(::bind(sListen,(LPSOCKADDR)&sin,sizeof(sin)) == SOCKET_ERROR)
    {
        printf("Failed bind()\n");
        return 0;
    }
    //進入監聽模式
    if(::listen(sListen,2) == SOCKET_ERROR)
    {
        printf("Failed listen()\n");
        return 0;
    }
    //循環接受客戶的連接請求
    sockaddr_in remoteAddr;
    int nAddrLen = sizeof(remoteAddr);
    SOCKET sClient;
    char szText[] = "TCP Server Demo!\r\n";
    while(TRUE)
    {
        //接受新連接
        sClient=::accept(sListen,(SOCKADDR*)&remoteAddr,&nAddrLen);
        if(sClient == INVALID_SOCKET)
        {
            printf("Failed accept()");
            continue;
        }
        printf("接受到一個連接：%s\r\n",inet_ntoa(remoteAddr.sin_addr));
        //向客戶端發送數據
        ::send(sClient,szText,strlen(szText),0);
        //關閉同客戶端的連接
        ::closesocket(sClient);
    }
    ::closesocket(sListen);
    return 0;
}

TCPClient 端代碼：

// TCPClient.cpp : 定義控制台應用程序的入口點。
//

#include "stdafx.h"
#include <winsock2.h>
#include <stdio.h>
#pragma comment(lib,"WS2_32")
class CInitSock
{
public:
    CInitSock(BYTE minorVer=2,BYTE majorVer=2)
    {
        WSADATA wsaData;
        WORD sockVersion = MAKEWORD(minorVer,majorVer);
        if(::WSAStartup(sockVersion,&wsaData)!=0)
        {
            exit(0);
        }
    }
    ~CInitSock()
    {
        ::WSACleanup();
    }
};
CInitSock initSock;

int _tmain(int argc, _TCHAR* argv[])
{
    SOCKET s= ::socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(s==INVALID_SOCKET)
    {
        printf("Failed socket()\n");
        return 0;
    }
    sockaddr_in servAddr;
    servAddr.sin_family=AF_INET;
    servAddr.sin_port=htons(4567);
    servAddr.sin_addr.S_un.S_addr=inet_addr("49.140.16.244");
    if(::connect(s,(sockaddr*)&servAddr,sizeof(servAddr))==-1)
    {
        printf("Failed connect()\n");
        return 0;
    }
    //接受數據
    char buff[256];
    int nRecv=::recv(s,buff,256,0);
    if(nRecv>0)
    {
        buff[nRecv] = '\0';
        printf("接受到數據：%s",buff);
    }
    ::closesocket(s);
    return 0;
}

結果：