【通信协议及编码】实验2：三种I/O模型回送服务器程序设计

一、实验目的

1. 掌握WinSock API I/O模型框架与原理
2. 掌握WinSock API Select I/O模型；
3. 掌握WinSock API WSAEventSelect I/O模型；
4. 掌握WinSock API I/O Completion Port模型。

二、实验环境

1. 操作系统：WINDOWS 7及以上
2. 开发工具：Microsoft VisualBasic6.0
3. 实验设备：PC

三、实验内容

1. 基于Select I/O模型创建一个回送服务器，服务器在5150端口上侦听TCP连接，并将收到的客户机数据回送客户机。
2. 设计一个WSAEventSelect I/O模型，服务器在端口5150侦听TCP连接，回送到客户机数据。
3. 开发一个简单的WinSock回声服务器，应用程序监听端口5150的TCP连接，并将收到的客户机数据回送给客户机。

客户机：

//程序说明:
//    这是一个回送客户机程序。连接TCP server，发送数据，接收服务器回送的数据
//    命令行参数:
//    client [-p:x] [-s:IP] [-n:x] [-o]
//           -p:x      远程服务器端口
//           -s:IP     服务器地址或主机名
//           -n:x      消息的发送次数
//           -o        只发送，不接收 
#include "stdafx.h"
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#pragma comment(lib,"ws2_32.lib")#define DEFAULT_COUNT       20
#define DEFAULT_PORT        5050
#define DEFAULT_BUFFER      2048
#define DEFAULT_MESSAGE     "\'A test message from client\'"char  szServer[128],          // 服务器主机名或地址
szMessage[1024];        // 发送到服务器的消息缓冲区
int   iPort = DEFAULT_PORT;  // 服务器端口
DWORD dwCount = DEFAULT_COUNT; // 发送消息的次数
BOOL  bSendOnly = FALSE;         // 只发送，不接收// 函数用法说明
void usage()
{printf("TcpClient: client [-p:x] [-s:IP] [-n:x] [-o]\n\n");printf("       -p:x      Remote port to send to\n");printf("       -s:IP     Server's IP address or hostname\n");printf("       -n:x      Number of times to send message\n");printf("       -o        Send messages only; don't receive\n");printf("\n");
}// 命令行参数解析
void ValidateArgs(int argc, char **argv)
{int	i;for (i = 1; i < argc; i++){if ((argv[i][0] == '-') || (argv[i][0] == '/')){switch (tolower(argv[i][1])){case 'p':if (strlen(argv[i]) > 3)iPort = atoi(&argv[i][3]);break;case 's':if (strlen(argv[i]) > 3)strcpy_s(szServer, sizeof(szServer), &argv[i][3]);break;case 'n': if (strlen(argv[i]) > 3)dwCount = atol(&argv[i][3]);break;case 'o':bSendOnly = TRUE;break;default:usage();break;}}}
}//    主线程初始化 Winsock, 分析命令行参数, 创建套接字, 连接服务器，发送和接受数据
int main(int argc, char **argv)
{WSADATA       wsd;SOCKET        sClient;char          szBuffer[DEFAULT_BUFFER];int           ret,i;struct sockaddr_in server;struct hostent    *host = NULL;if (argc < 2){usage();exit(1);}// 分析命令行参数，加载WinsockValidateArgs(argc, argv);if (WSAStartup(MAKEWORD(2, 2), &wsd) != 0){printf("Failed to load Winsock library! Error %d\n", WSAGetLastError());return 1;}elseprintf("Winsock library loaded successfully!\n");strcpy_s(szMessage, sizeof(szMessage), DEFAULT_MESSAGE);// 创建套接字，连接服务器sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if (sClient == INVALID_SOCKET){printf("socket() failed with error code %d\n", WSAGetLastError());return 1;}elseprintf("socket() looks fine!\n");server.sin_family = AF_INET;server.sin_port = htons(iPort);server.sin_addr.s_addr = inet_addr(szServer);if (server.sin_addr.s_addr == INADDR_NONE){host = gethostbyname(szServer);if (host == NULL){printf("Unable to resolve server %s\n", szServer);return 1;}elseprintf("The hostname resolved successfully!\n");CopyMemory(&server.sin_addr, host->h_addr_list[0], host->h_length);}if (connect(sClient, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR){printf("connect() failed with error code %d\n", WSAGetLastError());return 1;}elseprintf("connect() is pretty damn fine!\n");// 发送和接收数据printf("Sending and receiving data if any...\n");for (i = 0; i < (int)dwCount; i++){ret = send(sClient, szMessage, strlen(szMessage), 0);if (ret == 0)break;else if (ret == SOCKET_ERROR){printf("send() failed with error code %d\n", WSAGetLastError());break;}printf("send() should be fine. Send %d bytes\n", ret);if (!bSendOnly){ret = recv(sClient, szBuffer, DEFAULT_BUFFER, 0);if (ret == 0)        // 正常关闭{printf("It is a graceful close!\n");break;}else if (ret == SOCKET_ERROR){printf("recv() failed with error code %d\n", WSAGetLastError());break;}szBuffer[ret] = '\0';printf("recv() is OK. Received %d bytes: %s\n", ret, szBuffer);}}if (closesocket(sClient) == 0)printf("closesocket() is OK!\n");elseprintf("closesocket() failed with error code %d\n", WSAGetLastError());if (WSACleanup() == 0)printf("WSACleanup() is fine!\n");elseprintf("WSACleanup() failed with error code %d\n", WSAGetLastError());return 0;
}

1.Select I/O服务器

// 程序说明:
//
//    本程序演示如何基于Winsock 的 select() API I/O 模型创建一个回送服务器。
//    服务器在5150端口上侦听TCP连接
//    将收到的客户机数据再回送客户机，直到可会关闭连接#include <winsock2.h>
#include <windows.h>
#include <stdio.h>#pragma comment(lib,"ws2_32.lib")#define PORT 5150
#define DATA_BUFSIZE 8192typedef struct _SOCKET_INFORMATION {CHAR Buffer[DATA_BUFSIZE];WSABUF DataBuf;SOCKET Socket;OVERLAPPED Overlapped;DWORD BytesSEND;DWORD BytesRECV;
} SOCKET_INFORMATION, *LPSOCKET_INFORMATION;// 原型
BOOL CreateSocketInformation(SOCKET s);
void FreeSocketInformation(DWORD Index);// 全局变量
DWORD TotalSockets = 0;
LPSOCKET_INFORMATION SocketArray[FD_SETSIZE];int main(int argc, char **argv)
{SOCKET ListenSocket;SOCKET AcceptSocket;SOCKADDR_IN InternetAddr;WSADATA wsaData;INT Ret;FD_SET WriteSet;FD_SET ReadSet;DWORD i;DWORD Total;ULONG NonBlock;DWORD Flags;DWORD SendBytes;DWORD RecvBytes;if ((Ret = WSAStartup(0x0202, &wsaData)) != 0){printf("WSAStartup() failed with error %d\n", Ret);WSACleanup();return 1;}elseprintf("WSAStartup() is fine!\n");// 创建用于侦听的套接字if ((ListenSocket = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0,WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET){printf("WSASocket() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSASocket() is OK!\n");InternetAddr.sin_family = AF_INET;InternetAddr.sin_addr.s_addr = htonl(INADDR_ANY);InternetAddr.sin_port = htons(PORT);if (bind(ListenSocket, (PSOCKADDR)&InternetAddr, sizeof(InternetAddr)) == SOCKET_ERROR){printf("bind() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("bind() is OK!\n");if (listen(ListenSocket, 5)){printf("listen() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("listen() is OK!\n");// 将侦听套接字的阻塞模式转为非阻塞模式，这样服务器在等待连接到达期间不会发生阻塞NonBlock = 1;if (ioctlsocket(ListenSocket, FIONBIO, &NonBlock) == SOCKET_ERROR){printf("ioctlsocket() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("ioctlsocket() is OK!\n");while (TRUE){// 初始化等待网络I/O事件通知的读写套接字集合FD_ZERO(&ReadSet);FD_ZERO(&WriteSet);// 将侦听套接字加入套接字读集合FD_SET(ListenSocket, &ReadSet);// 基于当前状态缓冲区为每个套接字设置读/写// 如果缓冲区中有数据将其写入集合，否则读集for (i = 0; i < TotalSockets; i++)if (SocketArray[i]->BytesRECV > SocketArray[i]->BytesSEND)FD_SET(SocketArray[i]->Socket, &WriteSet);elseFD_SET(SocketArray[i]->Socket, &ReadSet);if ((Total = select(0, &ReadSet, &WriteSet, NULL, NULL)) == SOCKET_ERROR){printf("select() returned with error %d\n", WSAGetLastError());return 1;}elseprintf("select() is OK!\n");// 检查到达的连接在侦听套接字if (FD_ISSET(ListenSocket, &ReadSet)){Total--;if ((AcceptSocket = accept(ListenSocket, NULL, NULL)) != INVALID_SOCKET){// 设置套接字AcceptSocket为非阻塞模式// 这样服务器在调用WSASends发送数据时就不会被阻塞NonBlock = 1;if (ioctlsocket(AcceptSocket, FIONBIO, &NonBlock) == SOCKET_ERROR){printf("ioctlsocket(FIONBIO) failed with error %d\n", WSAGetLastError());return 1;}elseprintf("ioctlsocket(FIONBIO) is OK!\n");if (CreateSocketInformation(AcceptSocket) == FALSE){printf("CreateSocketInformation(AcceptSocket) failed!\n");return 1;}elseprintf("CreateSocketInformation() is OK!\n");}else{if (WSAGetLastError() != WSAEWOULDBLOCK){printf("accept() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("accept() is fine!\n");}}// 依次处理所有的套接字，SocketInfo为当前要处理的套接字信息for (i = 0; Total > 0 && i < TotalSockets; i++){LPSOCKET_INFORMATION SocketInfo = SocketArray[i];// 判断当前套接字的可读性，即是否有接入的连接请求或者可以接受数据if (FD_ISSET(SocketInfo->Socket, &ReadSet)){Total--;SocketInfo->DataBuf.buf = SocketInfo->Buffer;SocketInfo->DataBuf.len = DATA_BUFSIZE;Flags = 0;if (WSARecv(SocketInfo->Socket, &(SocketInfo->DataBuf), 1, &RecvBytes,&Flags, NULL, NULL) == SOCKET_ERROR){if (WSAGetLastError() != WSAEWOULDBLOCK){printf("WSARecv() failed with error %d\n", WSAGetLastError());FreeSocketInformation(i);}elseprintf("WSARecv() is OK!\n");continue;}else{SocketInfo->BytesRECV = RecvBytes;// 如果接收到0个字节，则表示对方关闭连接if (RecvBytes == 0){FreeSocketInformation(i);continue;}}}// 如果当前套接字在WriteSet集合中// 则表明if (FD_ISSET(SocketInfo->Socket, &WriteSet)){Total--;SocketInfo->DataBuf.buf = SocketInfo->Buffer + SocketInfo->BytesSEND;SocketInfo->DataBuf.len = SocketInfo->BytesRECV - SocketInfo->BytesSEND;if (WSASend(SocketInfo->Socket, &(SocketInfo->DataBuf), 1, &SendBytes, 0,NULL, NULL) == SOCKET_ERROR){if (WSAGetLastError() != WSAEWOULDBLOCK){printf("WSASend() failed with error %d\n", WSAGetLastError());FreeSocketInformation(i);}elseprintf("WSASend() is OK!\n");continue;}else{SocketInfo->BytesSEND += SendBytes;if (SocketInfo->BytesSEND == SocketInfo->BytesRECV){SocketInfo->BytesSEND = 0;SocketInfo->BytesRECV = 0;}}}}}
}BOOL CreateSocketInformation(SOCKET s)
{LPSOCKET_INFORMATION SI;printf("Accepted socket number %d\n", s);if ((SI = (LPSOCKET_INFORMATION)GlobalAlloc(GPTR, sizeof(SOCKET_INFORMATION))) == NULL){printf("GlobalAlloc() failed with error %d\n", GetLastError());return FALSE;}elseprintf("GlobalAlloc() for SOCKET_INFORMATION is OK!\n");// Prepare SocketInfo structure for useSI->Socket = s;SI->BytesSEND = 0;SI->BytesRECV = 0;SocketArray[TotalSockets] = SI;TotalSockets++;return(TRUE);
}void FreeSocketInformation(DWORD Index)
{LPSOCKET_INFORMATION SI = SocketArray[Index];DWORD i;closesocket(SI->Socket);printf("Closing socket number %d\n", SI->Socket);GlobalFree(SI);// Squash the socket arrayfor (i = Index; i < TotalSockets; i++){SocketArray[i] = SocketArray[i + 1];}TotalSockets--;
}

运行结果：
服务器：

客户机：

2.WSAEventSelect服务器

// WSAEventSelect模型回送服务器
// WSAEventSelect.cpp
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#pragma comment(lib,"ws2_32.lib")
#define PORT 5150
#define DATA_BUFSIZE 8192typedef struct _SOCKET_INFORMATION {CHAR Buffer[DATA_BUFSIZE];WSABUF DataBuf;SOCKET Socket;DWORD BytesSEND;DWORD BytesRECV;
} SOCKET_INFORMATION, *LPSOCKET_INFORMATION;BOOL CreateSocketInformation(SOCKET s);
void FreeSocketInformation(DWORD Event);DWORD EventTotal = 0;
WSAEVENT EventArray[WSA_MAXIMUM_WAIT_EVENTS];
LPSOCKET_INFORMATION SocketArray[WSA_MAXIMUM_WAIT_EVENTS];int main(int argc, char **argv)
{SOCKET Listen;SOCKET Accept;SOCKADDR_IN InternetAddr;LPSOCKET_INFORMATION SocketInfo;DWORD Event;WSANETWORKEVENTS NetworkEvents;WSADATA wsaData;DWORD Flags;DWORD RecvBytes;DWORD SendBytes;if (WSAStartup(0x0202, &wsaData) != 0){printf("WSAStartup() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAStartup() is OK!\n");if ((Listen = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET){printf("socket() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("socket() is OK!\n");if (CreateSocketInformation(Listen) == FALSE)printf("CreateSocketInformation() failed!\n");elseprintf("CreateSocketInformation() is OK lol!\n");if (WSAEventSelect(Listen, EventArray[EventTotal - 1], FD_ACCEPT | FD_CLOSE) == SOCKET_ERROR){printf("WSAEventSelect() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAEventSelect() is pretty fine!\n");InternetAddr.sin_family = AF_INET;InternetAddr.sin_addr.s_addr = htonl(INADDR_ANY);InternetAddr.sin_port = htons(PORT);if (bind(Listen, (PSOCKADDR)&InternetAddr, sizeof(InternetAddr)) == SOCKET_ERROR){printf("bind() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("bind() is OK!\n");if (listen(Listen, 5)){printf("listen() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("listen() is OK!\n");while (TRUE){// 等待套接字接受I/O通知if ((Event = WSAWaitForMultipleEvents(EventTotal, EventArray, FALSE, WSA_INFINITE, FALSE)) == WSA_WAIT_FAILED){printf("WSAWaitForMultipleEvents() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAWaitForMultipleEvents() is pretty damn OK!\n");if (WSAEnumNetworkEvents(SocketArray[Event - WSA_WAIT_EVENT_0]->Socket,EventArray[Event - WSA_WAIT_EVENT_0], &NetworkEvents) == SOCKET_ERROR){printf("WSAEnumNetworkEvents() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAEnumNetworkEvents() should be fine!\n");if (NetworkEvents.lNetworkEvents & FD_ACCEPT){if (NetworkEvents.iErrorCode[FD_ACCEPT_BIT] != 0){printf("FD_ACCEPT failed with error %d\n", NetworkEvents.iErrorCode[FD_ACCEPT_BIT]);break;}if ((Accept = accept(SocketArray[Event - WSA_WAIT_EVENT_0]->Socket, NULL, NULL)) == INVALID_SOCKET){printf("accept() failed with error %d\n", WSAGetLastError());break;}elseprintf("accept() should be OK!\n");if (EventTotal > WSA_MAXIMUM_WAIT_EVENTS){printf("Too many connections - closing socket...\n");closesocket(Accept);break;}CreateSocketInformation(Accept);if (WSAEventSelect(Accept, EventArray[EventTotal - 1], FD_READ | FD_WRITE | FD_CLOSE) == SOCKET_ERROR){printf("WSAEventSelect() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAEventSelect() is OK!\n");printf("Socket %d got connected...\n", Accept);}// 如果读取和写入事件发生，试着对数据缓冲区读取和写入数据if (NetworkEvents.lNetworkEvents & FD_READ || NetworkEvents.lNetworkEvents & FD_WRITE){if (NetworkEvents.lNetworkEvents & FD_READ && NetworkEvents.iErrorCode[FD_READ_BIT] != 0){printf("FD_READ failed with error %d\n", NetworkEvents.iErrorCode[FD_READ_BIT]);break;}elseprintf("FD_READ is OK!\n");if (NetworkEvents.lNetworkEvents & FD_WRITE && NetworkEvents.iErrorCode[FD_WRITE_BIT] != 0){printf("FD_WRITE failed with error %d\n", NetworkEvents.iErrorCode[FD_WRITE_BIT]);break;}elseprintf("FD_WRITE is OK!\n");SocketInfo = SocketArray[Event - WSA_WAIT_EVENT_0];// 当收到的字节数为0时读取数据if (SocketInfo->BytesRECV == 0){SocketInfo->DataBuf.buf = SocketInfo->Buffer;SocketInfo->DataBuf.len = DATA_BUFSIZE;Flags = 0;if (WSARecv(SocketInfo->Socket, &(SocketInfo->DataBuf), 1, &RecvBytes,&Flags, NULL, NULL) == SOCKET_ERROR){if (WSAGetLastError() != WSAEWOULDBLOCK){printf("WSARecv() failed with error %d\n", WSAGetLastError());FreeSocketInformation(Event - WSA_WAIT_EVENT_0);return 1;}}else{printf("WSARecv() is working!\n");SocketInfo->BytesRECV = RecvBytes;}}// 当收到的字节数大于发送的字节数时发送数据if (SocketInfo->BytesRECV > SocketInfo->BytesSEND){SocketInfo->DataBuf.buf = SocketInfo->Buffer + SocketInfo->BytesSEND;SocketInfo->DataBuf.len = SocketInfo->BytesRECV - SocketInfo->BytesSEND;if (WSASend(SocketInfo->Socket, &(SocketInfo->DataBuf), 1, &SendBytes, 0,NULL, NULL) == SOCKET_ERROR){if (WSAGetLastError() != WSAEWOULDBLOCK){printf("WSASend() failed with error %d\n", WSAGetLastError());FreeSocketInformation(Event - WSA_WAIT_EVENT_0);return 1;}}else{printf("WSASend() is fine! Thank you...\n");SocketInfo->BytesSEND += SendBytes;if (SocketInfo->BytesSEND == SocketInfo->BytesRECV){SocketInfo->BytesSEND = 0;SocketInfo->BytesRECV = 0;}}}}if (NetworkEvents.lNetworkEvents & FD_CLOSE){if (NetworkEvents.iErrorCode[FD_CLOSE_BIT] != 0){printf("FD_CLOSE failed with error %d\n", NetworkEvents.iErrorCode[FD_CLOSE_BIT]);break;}elseprintf("FD_CLOSE is OK!\n");printf("Closing socket information %d\n", SocketArray[Event - WSA_WAIT_EVENT_0]->Socket);FreeSocketInformation(Event - WSA_WAIT_EVENT_0);}}return 0;
}BOOL CreateSocketInformation(SOCKET s)
{LPSOCKET_INFORMATION SI;if ((EventArray[EventTotal] = WSACreateEvent()) == WSA_INVALID_EVENT){printf("WSACreateEvent() failed with error %d\n", WSAGetLastError());return FALSE;}elseprintf("WSACreateEvent() is OK!\n");if ((SI = (LPSOCKET_INFORMATION)GlobalAlloc(GPTR, sizeof(SOCKET_INFORMATION))) == NULL){printf("GlobalAlloc() failed with error %d\n", GetLastError());return FALSE;}elseprintf("GlobalAlloc() for LPSOCKET_INFORMATION is OK!\n");// 准备使用SocketInfo结构SI->Socket = s;SI->BytesSEND = 0;SI->BytesRECV = 0;SocketArray[EventTotal] = SI;EventTotal++;return(TRUE);
}void FreeSocketInformation(DWORD Event)
{LPSOCKET_INFORMATION SI = SocketArray[Event];DWORD i;closesocket(SI->Socket);GlobalFree(SI);if (WSACloseEvent(EventArray[Event]) == TRUE)printf("WSACloseEvent() is OK!\n\n");elseprintf("WSACloseEvent() failed miserabily!\n\n");// 将套接字和事件从数组删除for (i = Event; i < EventTotal; i++){EventArray[i] = EventArray[i + 1];SocketArray[i] = SocketArray[i + 1];}EventTotal--;
}

运行结果：
服务器：

客户机：

3.I/O Completion Port

// I/O完成端口服务器程序
//程序名：IOComplete.cpp#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#pragma comment(lib,"ws2_32.lib")
#define PORT 5150
#define DATA_B UFSIZE 8192// 类型定义
typedef struct
{OVERLAPPED Overlapped;WSABUF DataBuf;CHAR Buffer[DATA_BUFSIZE];DWORD BytesSEND;DWORD BytesRECV;
} PER_IO_OPERATION_DATA, *LPPER_IO_OPERATION_DATA;// 结构定义
typedef struct
{SOCKET Socket;
} PER_HANDLE_DATA, *LPPER_HANDLE_DATA;// 原型声明
DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID);int main(int argc, char **argv)
{SOCKADDR_IN InternetAddr;SOCKET Listen;HANDLE ThreadHandle;SOCKET Accept;HANDLE CompletionPort;SYSTEM_INFO SystemInfo;LPPER_HANDLE_DATA PerHandleData;LPPER_IO_OPERATION_DATA PerIoData;int i;DWORD RecvBytes;DWORD Flags;DWORD ThreadID;WSADATA wsaData;DWORD Ret;if ((Ret = WSAStartup((2, 2), &wsaData)) != 0){printf("WSAStartup() failed with error %d\n", Ret);return 1;}elseprintf("WSAStartup() is OK!\n");// 设置一个I/O完成端口if ((CompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0)) == NULL){printf("CreateIoCompletionPort() failed with error %d\n", GetLastError());return 1;}elseprintf("CreateIoCompletionPort() is damn OK!\n");// 测试系统中有多少CPU处理器GetSystemInfo(&SystemInfo);// 基于系统可用的处理器创建工作线程// 为每个处理器创建两个线程for (i = 0; i < (int)SystemInfo.dwNumberOfProcessors * 2; i++){// 创建一个服务器工作线程，并且传递一个完成端口给这个线程if ((ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread, CompletionPort, 0, &ThreadID)) == NULL){printf("CreateThread() failed with error %d\n", GetLastError());return 1;}elseprintf("CreateThread() is OK!\n");// 关闭线程句柄CloseHandle(ThreadHandle);}// 创建服务器监听套接字if ((Listen = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET){printf("WSASocket() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSASocket() is OK!\n");InternetAddr.sin_family = AF_INET;InternetAddr.sin_addr.s_addr = htonl(INADDR_ANY);InternetAddr.sin_port = htons(PORT);if (bind(Listen, (PSOCKADDR)&InternetAddr, sizeof(InternetAddr)) == SOCKET_ERROR){printf("bind() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("bind() is fine!\n");// 开始监听if (listen(Listen, 5) == SOCKET_ERROR){printf("listen() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("listen() is working...\n");// 接受连接并且交给完成端口处理while (TRUE){if ((Accept = WSAAccept(Listen, NULL, NULL, NULL, 0)) == SOCKET_ERROR){printf("WSAAccept() failed with error %d\n", WSAGetLastError());return 1;}elseprintf("WSAAccept() looks fine!\n");// 为套接字分配内存if ((PerHandleData = (LPPER_HANDLE_DATA)GlobalAlloc(GPTR, sizeof(PER_HANDLE_DATA))) == NULL){printf("GlobalAlloc() failed with error %d\n", GetLastError());return 1;}elseprintf("GlobalAlloc() for LPPER_HANDLE_DATA is OK!\n");// 将套接字与完成端口关联起来printf("Socket number %d got connected...\n", Accept);PerHandleData->Socket = Accept;if (CreateIoCompletionPort((HANDLE)Accept, CompletionPort, (DWORD)PerHandleData, 0) == NULL){printf("CreateIoCompletionPort() failed with error %d\n", GetLastError());return 1;}elseprintf("CreateIoCompletionPort() is OK!\n");// 创建一个I/O套接字信息结构体，为下面调用的WSARecv函数服务if ((PerIoData = (LPPER_IO_OPERATION_DATA)GlobalAlloc(GPTR, sizeof(PER_IO_OPERATION_DATA))) == NULL){printf("GlobalAlloc() failed with error %d\n", GetLastError());return 1;}elseprintf("GlobalAlloc() for LPPER_IO_OPERATION_DATA is OK!\n");ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));PerIoData->BytesSEND = 0;PerIoData->BytesRECV = 0;PerIoData->DataBuf.len = DATA_BUFSIZE;PerIoData->DataBuf.buf = PerIoData->Buffer;Flags = 0;if (WSARecv(Accept, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags, &(PerIoData->Overlapped), NULL) == SOCKET_ERROR){if (WSAGetLastError() != ERROR_IO_PENDING){printf("WSARecv() failed with error %d\n", WSAGetLastError());return 1;}}elseprintf("WSARecv() is OK!\n");}//end main
}DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID)
{HANDLE CompletionPort = (HANDLE)CompletionPortID;DWORD BytesTransferred;LPPER_HANDLE_DATA PerHandleData;LPPER_IO_OPERATION_DATA PerIoData;DWORD SendBytes, RecvBytes;DWORD Flags;while (TRUE){if (GetQueuedCompletionStatus(CompletionPort, &BytesTransferred,(LPDWORD)&PerHandleData, (LPOVERLAPPED *)&PerIoData, INFINITE) == 0){printf("GetQueuedCompletionStatus() failed with error %d\n", GetLastError());return 0;}elseprintf("GetQueuedCompletionStatus() is OK!\n");// 检查套接字是否发生了错误，如果发生了错误，关闭套接字并释放相关内存if (BytesTransferred == 0){printf("Closing socket %d\n", PerHandleData->Socket);if (closesocket(PerHandleData->Socket) == SOCKET_ERROR){printf("closesocket() failed with error %d\n", WSAGetLastError());return 0;}elseprintf("closesocket() is fine!\n");GlobalFree(PerHandleData);GlobalFree(PerIoData);continue;}// 如果ByteRECV字段等于0，表示一个WSARecv调用刚刚完成if (PerIoData->BytesRECV == 0){PerIoData->BytesRECV = BytesTransferred;PerIoData->BytesSEND = 0;//printf("客户消息：%s\n",PerIoData->DataBuf.buf);}else{PerIoData->BytesSEND += BytesTransferred;}if (PerIoData->BytesRECV > PerIoData->BytesSEND){// 调用WSASend（）发送，直到所有收到的字节被发送ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));PerIoData->DataBuf.buf = PerIoData->Buffer + PerIoData->BytesSEND;PerIoData->DataBuf.len = PerIoData->BytesRECV - PerIoData->BytesSEND;if (WSASend(PerHandleData->Socket, &(PerIoData->DataBuf), 1, &SendBytes, 0,&(PerIoData->Overlapped), NULL) == SOCKET_ERROR){if (WSAGetLastError() != ERROR_IO_PENDING){printf("WSASend() failed with error %d\n", WSAGetLastError());return 0;}}elseprintf("WSASend() is OK!\n");}else{PerIoData->BytesRECV = 0;// 现在没有多余的数据可以发送，发出另外一个WSARecv（）请求Flags = 0;ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));PerIoData->DataBuf.len = DATA_BUFSIZE;PerIoData->DataBuf.buf = PerIoData->Buffer;if (WSARecv(PerHandleData->Socket, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags,&(PerIoData->Overlapped), NULL) == SOCKET_ERROR){if (WSAGetLastError() != ERROR_IO_PENDING){printf("WSARecv() failed with error %d\n", WSAGetLastError());return 0;}}elseprintf("WSARecv() is OK!\n");}}
}

运行结果：
服务器：

客户机：