A sample that using the completion port I/O model
秋
//
// Description:
//
// This sample illustrates how to develop a simple echo server
Winsock
// application using the completeion port I/O model. This
// sample is implemented as a console-style application and simply
prints
// messages when connections are established and removed from the
server.
// The application listens for TCP connections on port 5150 and
accepts them
// as they arrive. When this application receives data from a
client, it
// simply echos (this is why we call it an echo server) the data
back in
// it's original form until the client closes the connection.
//
// Compile:
//
// cl -o iocmplt iocmplt.cpp ws2_32.lib
//
// Command Line Options:
//
// iocmplt.exe
//
// Note: There are no command line options for this sample.
#include "StdAfx.h"
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#define PORT 5150
#define DATA_BUFSIZE 8192
typedef struct
{
OVERLAPPED Overlapped;
WSABUF DataBuf;
CHAR Buffer[DATA_BUFSIZE];
DWORD BytesSEND;
DWORD BytesRECV;
} PER_IO_OPERATION_DATA, * LPPER_IO_OPERATION_DATA;
typedef struct
{
SOCKET Socket;
} PER_HANDLE_DATA, * LPPER_HANDLE_DATA;
DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID);
void main(void)
{
SOCKADDR_IN InternetAddr;
SOCKET Listen;
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(0x0202, &wsaData)) != 0)
{
printf("WSAStartup failed with error %d\n", Ret);
return;
}
// Setup an I/O completion port.
if ((CompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE,
NULL, 0, 0)) == NULL)
{
printf( "CreateIoCompletionPort failed with error: %d\n",
GetLastError());
return;
}
// Determine how many processors are on the system.
GetSystemInfo(&SystemInfo);
// Create worker threads based on the number of processors available
on the
// system. Create two worker threads for each processor.
for(i = 0; i < SystemInfo.dwNumberOfProcessors * 2; i++)
{
HANDLE ThreadHandle;
// Create a server worker thread and pass the completion port to
the thread.
if ((ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread,
CompletionPort,
0, &ThreadID)) == NULL)
{
printf("CreateThread() failed with error %d\n",
GetLastError());
return;
}
// Close the thread handle
CloseHandle(ThreadHandle);
}
// Create a listening socket
if ((Listen = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0,
WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET)
{
printf("WSASocket() failed with error %d\n", WSAGetLastError());
return;
}
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;
}
// Prepare socket for listening
if (listen(Listen, 5) == SOCKET_ERROR)
{
printf("listen() failed with error %d\n", WSAGetLastError());
return;
}
// Accept connections and assign to the completion port.
while(TRUE)
{
if ((Accept = WSAAccept(Listen, NULL, NULL, NULL, 0)) ==
SOCKET_ERROR)
{
printf("WSAAccept() failed with error %d\n",
WSAGetLastError());
return;
}
// Create a socket information structure to associate with the
socket
if ((PerHandleData = (LPPER_HANDLE_DATA) GlobalAlloc(GPTR,
sizeof(PER_HANDLE_DATA))) == NULL)
{
printf("GlobalAlloc() failed with error %d\n",
GetLastError());
return;
}
// Associate the accepted socket with the original completion
port.
printf("Socket number %d connected\n", Accept);
PerHandleData->Socket = Accept;
if (CreateIoCompletionPort((HANDLE) Accept, CompletionPort,
(DWORD) PerHandleData,
0) == NULL)
{
printf("CreateIoCompletionPort failed with error %d\n",
GetLastError());
return;
}
// Create per I/O socket information structure to associate with
the
// WSARecv call below.
if ((PerIoData = (LPPER_IO_OPERATION_DATA) GlobalAlloc(GPTR,
sizeof(PER_IO_OPERATION_DATA))) == NULL)
{
printf("GlobalAlloc() failed with error %d\n",
GetLastError());
return;
}
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;
}
}
}
}
DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID)
{
HANDLE CompletionPort = (HANDLE) CompletionPortID;
DWORD BytesTransferred;
LPOVERLAPPED Overlapped;
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;
}
// First check to see if an error has occured on the socket and
if so
// then close the socket and cleanup the SOCKET_INFORMATION
structure
// associated with the socket.
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;
}
GlobalFree(PerHandleData);
GlobalFree(PerIoData);
continue;
}
// Check to see if the BytesRECV field equals zero. If this is
so, then
// this means a WSARecv call just completed so update the
BytesRECV field
// with the BytesTransferred value from the completed WSARecv()
call.
if (PerIoData->BytesRECV == 0)
{
PerIoData->BytesRECV = BytesTransferred;
PerIoData->BytesSEND = 0;
}
else
{
PerIoData->BytesSEND += BytesTransferred;
}
if (PerIoData->BytesRECV > PerIoData->BytesSEND)
{
// Post another WSASend() request.
// Since WSASend() is not gauranteed to send all of the bytes
requested,
// continue posting WSASend() calls until all received bytes
are sent.
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;
}
}
}
else
{
PerIoData->BytesRECV = 0;
// Now that there are no more bytes to send post another
WSARecv() request.
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;
}
}
}
}
}
