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yolandalinz 发表于 2013-2-21 17:41 
是c。 测试的对象是wsaBuf.buf, 也就是所谓的端口缓存。这段代码是往一个端口写东西的一部分。一班般还会有 ...
多谢， 这是 winsock() codes for select() 模型，能介绍一下缓冲区的工作原理？
ntSelectModel.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <stdlib.h>
#include "winsock2.h"
#include <conio.h>
//winsock 2.2 library
#pragma comment(lib,"ws2_32.lib")
#define PORT 8888
#define BUFFERSIZE 100
#define ADDR "127.0.0.1"
#define ECHO 0xFE
#define REPLY 0xFF
//套接字环境
typedef struct _tagSOCKET_INFO {
OVERLAPPED overlap;
WSABUF wsaBuf;
char buf[BUFFERSIZE];
SOCKET socket;
DWORD bytesend;
DWORD bytesrecv;
} SOCKET_INFO, * LPSOCKET_INFO;
BOOL CreateSocketInfo(SOCKET s);
void FreeSocketInfo(DWORD Index);
DWORD totalsocks = 0;
LPSOCKET_INFO socklist[FD_SETSIZE];
#pragma hdrstop
//---------------------------------------------------------------------------
#pragma argsused
int main(int argc, char* argv[])
{
//监听、连接套接字
SOCKET listensocket,acceptsocket;
//服务端地址
SOCKADDR_IN serAddr;
WSADATA wsaData;
//select集合
struct fd_set fdwrite,fdread;
//缓冲区准备好的套接字计数
DWORD index,sockok;
//套接字工作模式
ULONG sockmode;
DWORD flags;
//接收发送数据计数
DWORD datasend,datarecv;
//客户端地址
SOCKADDR_IN cliAddr;
int cliAddrLen;
//初始化Winsock 2.2
printf("\nInitialising Winsock...\n");
if (WSAStartup(MAKEWORD(2,2),&wsaData) != 0)
{
fprintf(stderr,"WSAStartup() failed %d\n, WSAGetLastError()");
exit(0);
}
printf("Initialised successfully.\n");
//创建监听socket
printf("\nCreating TCP socket...\n");
if((listensocket = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0,
WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET)
{
printf("Creation of socket failed %d\n", WSAGetLastError());
WSACleanup();
return 0;
}
//设置SOCKADDR_IN地址结构
serAddr.sin_family = AF_INET;
serAddr.sin_addr.s_addr = htonl(INADDR_ANY);
// serAddr.sin_addr.s_addr = inet_addr(ADDR);
serAddr.sin_port = htons(PORT);
//绑定套接字
if (bind(listensocket, (SOCKADDR *) &serAddr, sizeof(serAddr))
== SOCKET_ERROR)
{
printf("bind failed with error %d\n", WSAGetLastError());
closesocket(listensocket);
WSACleanup();
return 0;
}
//监听连接
if (listen(listensocket, 5))
{
printf("listen failed with error %d\n", WSAGetLastError());
closesocket(listensocket);
WSACleanup();
return 0;
}
printf("Listening on the %s:%d...\n",
inet_ntoa(serAddr.sin_addr), htons(serAddr.sin_port));
//更改监听套接字工作模式至非阻塞模式+select
sockmode = 1;
if (ioctlsocket(listensocket, FIONBIO, &sockmode) == SOCKET_ERROR)
{
printf("ioctlsocket() failed \n");
return 0;
}
while(TRUE)
{
//初始化读写套接字集合
FD_ZERO(&fdread);
FD_ZERO(&fdwrite);
//将监听套接字添加到集合中，以便检查连接请求
FD_SET(listensocket, &fdread);
//根据缓冲区当前的状态来为套接字设置可读性及可写性测试
//譬如当收到数据以后则要测试缓冲区的可写性
//否则就测试其可读性
for (index = 0; index < totalsocks; index++)
if (socklist[index]->bytesrecv > socklist[index]->bytesend)
FD_SET(socklist[index]->socket, &fdwrite);
else
FD_SET(socklist[index]->socket, &fdread);
//选择感兴趣的套接字集合
if ((sockok = select(0, &fdread, &fdwrite,
NULL, NULL)) == SOCKET_ERROR)
{
fprintf(stderr, "select failed: %d\n", WSAGetLastError());
return -1;
}
//检查到来的连接请求
if (FD_ISSET(listensocket, &fdread))
{
sockok--;
//cliAddrLen必须初始化为cliAddr的大小
cliAddrLen=sizeof(cliAddr);
if ((acceptsocket = accept(listensocket,
(sockaddr*)&cliAddr,&cliAddrLen)) != INVALID_SOCKET)
{
//接受连接并将新的套接字设置为非阻塞模式
sockmode = 1;
if (ioctlsocket(acceptsocket, FIONBIO, &sockmode) == SOCKET_ERROR)
{
printf("ioctlsocket() failed with error %d\n", WSAGetLastError());
return 0;
}
//为新套接字创建工作环境
if (CreateSocketInfo(acceptsocket) == FALSE)
return 0;
printf("successfully got a connection from %s:%d.\n",
inet_ntoa(cliAddr.sin_addr), ntohs(cliAddr.sin_port));
}
else
{
if (WSAGetLastError() != WSAEWOULDBLOCK)
{
printf("accept() failed with error %d\n", WSAGetLastError());
return 0;
}
}
}
//为所有的sockok套接字检查读写通知
for (index = 0; sockok > 0 && index < totalsocks; index++)
{
LPSOCKET_INFO sockinfo = socklist[index];
//缓冲区可读性测试
if (FD_ISSET(sockinfo->socket, &fdread))
{
sockok--;
sockinfo->wsaBuf.buf = sockinfo->buf;
sockinfo->wsaBuf.len = BUFFERSIZE;
flags = 0;
if (WSARecv(sockinfo->socket,
&(sockinfo->wsaBuf), 1, &datarecv,
&flags, NULL, NULL) == SOCKET_ERROR)
{
if (WSAGetLastError() != WSAEWOULDBLOCK)
{
printf("Receive failed with error\n");
FreeSocketInfo(index);
}
continue;
}
else
{
//cliAddrLen必须初始化为cliAddr的大小
cliAddrLen=sizeof(cliAddr);
//获取客户端地址信息
if(getpeername(sockinfo->socket,(sockaddr*)&cliAddr,&cliAddrLen))
{
printf("getpeername failed with error %d\n", WSAGetLastError());
}
printf( "The following data comes from %s:%d\n",
inet_ntoa(cliAddr.sin_addr),htons(cliAddr.sin_port));
//接收的数据量
sockinfo->bytesrecv = datarecv;
//显示接收到的数据
printf("%s\n",sockinfo->wsaBuf.buf);
printf("Waiting to receive data...\n");
//若发现exit则退出处理循环
if(strncmp(sockinfo->wsaBuf.buf,"exit",sizeof("exit"))==0)
{
printf("exit the receiving loop\n");
break;
}
//连接关闭，则接收到0字节
if (datarecv == 0)
{
FreeSocketInfo(index);
continue;
}
}
}
//缓冲区可写性测试
if (FD_ISSET(sockinfo->socket, &fdwrite))
{
sockok--;
//继续发送剩余部分
sockinfo->wsaBuf.buf = sockinfo->buf + sockinfo->bytesend;
sockinfo->wsaBuf.len = sockinfo->bytesrecv - sockinfo->bytesend;
if (WSASend(sockinfo->socket,
&(sockinfo->wsaBuf), 1, &datasend, 0,
NULL, NULL) == SOCKET_ERROR)
{
if (WSAGetLastError() != WSAEWOULDBLOCK)
{
printf("Send failed with error\n");
FreeSocketInfo(index);
}
continue;
}
else
{
//增加已发送数据计数
sockinfo->bytesend += datasend;
//二者相等时说明接收数据已发送完毕
if (sockinfo->bytesend == sockinfo->bytesrecv)
{
sockinfo->bytesend = 0;
sockinfo->bytesrecv = 0;
ZeroMemory(sockinfo->wsaBuf.buf,BUFFERSIZE);
}
}
}
}
}
WSACleanup();
getch();
return 0;
}
//---------------------------------------------------------------------------
void FreeSocketInfo(DWORD Index)
{
LPSOCKET_INFO sockinfo = socklist[Index];
DWORD loop;
closesocket(sockinfo->socket);
printf("Closing socket.....\n");
GlobalFree(sockinfo);
//从数组中移除
for (loop = Index; loop < totalsocks-1; loop++)
{
socklist[loop] = socklist[loop + 1];
}
//递减已关闭连接套接字的计数
totalsocks--;
'7d
BOOL CreateSocketInfo(SOCKET s)
{
LPSOCKET_INFO sockinfo;
printf("Accepted socket!\n");
//从堆上分配内存
if ((sockinfo = (LPSOCKET_INFO) GlobalAlloc(GPTR,
sizeof(SOCKET_INFO))) == NULL)
{
printf("GlobalAlloc() failed\n");
return FALSE;
}
//套接字相关
sockinfo->socket=s;
sockinfo->bytesend=sockinfo->bytesrecv =0;
socklist[totalsocks]=sockinfo;
//递增已接受连接套接字的计数
totalsocks++;
return TRUE;
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二毛与鱿鱼不得不说的事 (2009-3-28) edith921 
发表于 2013-2-21 13:12
