windows下的网络编程——Select模型实例，一款ECHO服务的实现代码

别的不多说了，看代码吧。

ECHO服务器端：

#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>

#define DEFAULT_PORT	5566
#define BUFFER_SIZE		4096
#define DEFAULT_ADDR_LEN 128
#define MAX_CLIENT (FD_SETSIZE -1)
int nPort	= DEFAULT_PORT;
char szAddr[DEFAULT_ADDR_LEN];
char szBuffer[BUFFER_SIZE];
BOOL bInterface = FALSE;
BOOL bEchoBack	= FALSE;

void usage(void);
void checkArgv(int argc, char **argv);
BOOL insertSocket(SOCKET *pClient, SOCKET s);

int main(int argc, char *argv[])
{
WSAData wsaData;
WORD wVersion = MAKEWORD(2,2);
SOCKET s, sClient;
SOCKADDR_IN sa, saRemote;
int nRet, nLen, i, nLeft, idx, nRecvLen;
SOCKET arrClientSocket[MAX_CLIENT] = {INVALID_SOCKET};

checkArgv(argc, argv);
nRet = WSAStartup(wVersion, &wsaData);

if (SOCKET_ERROR == nRet)
{
printf("/nWindows socket startup error:%d/n", WSAGetLastError());
return 1;
}

printf("Socket initalization...../n");

s = socket(AF_INET, SOCK_STREAM, 0);
if (INVALID_SOCKET == s)
{
printf("/nScoket was created error:%d/n", WSAGetLastError());
return 1;
}

printf("socket was created/n");

nLen = sizeof(SOCKADDR_IN);
memset(&sa, 0, nLen);
sa.sin_family = AF_INET;
sa.sin_port	  = htons(nPort);

if (bInterface)
{
sa.sin_addr.s_addr = inet_addr(szAddr);
}
else
{
sa.sin_addr.s_addr = htonl(INADDR_ANY);
}

nRet = bind(s, (LPSOCKADDR)&sa, nLen);
if (SOCKET_ERROR == nRet)
{
printf("Socket bind error:%d/n", WSAGetLastError());
return 1;
}

printf("bind was successed/n");

nRet = listen(s, 8);
if (SOCKET_ERROR == nRet)
{
printf("Socket listen error:%d/n", WSAGetLastError());
return 1;
}

printf("listen was successed/n");

fd_set fdRead;
for(i = 0;i < MAX_CLIENT; i++)
{
arrClientSocket[i] = INVALID_SOCKET;
}

for(;;)
{
//初始化队列，将所有套接字加入。
FD_ZERO(&fdRead);
FD_SET(s, &fdRead);
for(i = 0; i < MAX_CLIENT; i++)
{
if (INVALID_SOCKET != arrClientSocket[i])
{
FD_SET(arrClientSocket[i], &fdRead);
}
}

nRet = select(0, &fdRead, NULL, NULL, NULL);
if (SOCKET_ERROR == nRet)
{
printf("/nSelect() error:%d/n", WSAGetLastError());
break;
}

if (nRet > 0)
{
//说明有新SOCKET连接到服务器
if(FD_ISSET(s, &fdRead))
{
sClient = accept(s, (LPSOCKADDR)&saRemote, &nLen);
insertSocket(arrClientSocket, sClient);
printf("Sokcet:%d, was accept()/n", sClient);
continue;
}
for(i = 0; i < MAX_CLIENT; i++)
{
if (FD_ISSET(arrClientSocket[i], &fdRead))
{
memset(szBuffer, 0, BUFFER_SIZE);
nRet = recv(arrClientSocket[i], szBuffer, BUFFER_SIZE, 0);
if (nRet <= 0)
{
closesocket(arrClientSocket[i]);
arrClientSocket[i] = INVALID_SOCKET;
continue;
}

nRecvLen = nRet;
printf("Socket:%d, %d, send data:%s/n", arrClientSocket[i], nRet, szBuffer);

if (!bEchoBack)
{
nRet = getpeername(arrClientSocket[i], (LPSOCKADDR)&saRemote, &nLen);
if (SOCKET_ERROR == nRet)
{
printf("/ngetpeername() error:%d/n", WSAGetLastError());
continue;
}
nLeft = nRecvLen;
idx = 0;
while (nLeft > 0)
{
nRet = send(arrClientSocket[i], &szBuffer[idx], nLeft, 0);
if (0 == nRet)
break;
else if (SOCKET_ERROR == nRet)
{
printf("Send() failed:%d/n", WSAGetLastError());
break;
}
nLeft -= nRet;
idx += nRet;
}
}
}
}
}
}
closesocket(s);
WSACleanup();
return 0;
}

void usage(void)
{
printf("usage: selectecho.exe [-p:5566] [-i:127.0.0.1] [-o]/n/n");
printf("/t-p:监听的端口号， 在1024到65535之间/n");
printf("/t-i:监听的服务器地址/n");
printf("/t-o:是否将数据发回客户端/n/n");
ExitProcess(1);
}

void checkArgv(int argc, char **argv)
{
int i;
for(i = 1; i < argc; i++)
{
if(('/' == argv[i][0]) || ('-' == argv[i][1]))
{
switch(tolower(argv[i][1]))
{
case 'p':
nPort = atoi(&argv[i][3]);
break;
case 'i':
memset(szAddr, 0, DEFAULT_ADDR_LEN);
strcpy(szAddr, &argv[i][3]);
bInterface = TRUE;
break;
case 'o':
bEchoBack = TRUE;
break;
default:
usage();
break;
}
}
}
}

BOOL insertSocket(SOCKET *pClient, SOCKET s)
{
int i;
BOOL bResult = FALSE;
for(i = 0; i < MAX_CLIENT; i++)
{
if (INVALID_SOCKET == pClient[i])
{
pClient[i] = s;
bResult = TRUE;
break;
}
}
return bResult;
}

测试用客户端，目前地址写在了程序中，用户可以自行修改。

#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>

#define SERVER_PORT	5566
#define BUFFER_SIZE 4096
#define MAX_ADDR_LEN 128

int nPort = SERVER_PORT;
char szBuffer[BUFFER_SIZE];
char szAddr[MAX_ADDR_LEN];

void usage(void);
void checkArgv(int argc, char **argv);

int main(int argc, char *argv[])
{
int nRet, nLen, nAddrLen, i;
SOCKET s;
SOCKADDR_IN sa;

WSAData wsaData;
WORD wVersion = MAKEWORD(2,2);

checkArgv(argc, argv);

nRet = WSAStartup(wVersion, &wsaData);
if (SOCKET_ERROR == nRet)
{
printf("Socket init error/n");
return 1;
}

s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (INVALID_SOCKET == s)
{
printf("Socket was created failse:%d/n", WSAGetLastError());
closesocket(s);
WSACleanup();
return 1;
}

nAddrLen = sizeof(SOCKADDR_IN);
memset(&sa, 0, nAddrLen);
sa.sin_family = AF_INET;
sa.sin_port	  = htons(nPort);
sa.sin_addr.s_addr = inet_addr("127.0.0.1");

nRet = connect(s, (LPSOCKADDR)&sa, nAddrLen);
if (SOCKET_ERROR == nRet)
{
printf("socket connect() failse:%d/n", WSAGetLastError());
closesocket(s);
WSACleanup();
return 1;
}

for(;;)
{
printf("/nSend Message to ECHO:");
memset(szBuffer, 0, BUFFER_SIZE);
nRet = scanf("%s", szBuffer);
if (BUFFER_SIZE < nRet)
{
szBuffer[BUFFER_SIZE-1] = '/0';
}
if (0 == strcmp("quit",szBuffer)) break;		//输入QUIT退出当前客户端
nRet = send(s, szBuffer, strlen(szBuffer), 0);
if (SOCKET_ERROR == nRet)
{
printf("Socket send() failse:%d/n", WSAGetLastError());
break;
}
memset(szBuffer, 0, BUFFER_SIZE);
nRet = recv(s, szBuffer, BUFFER_SIZE, 0);
printf("Server ECHO back:%s/n", szBuffer);
}

closesocket(s);
WSACleanup();
return 0;
}

void usage(void)
{
printf("usage: selectecho.exe -i:127.0.0.1 [-p:5566]/n");
printf("/t-i:服务器地址/n");
printf("/t-p:服务器端口号， 在1024到65535之间/n");
ExitProcess(1);
}

void checkArgv(int argc, char **argv)
{
int i;
memset(szAddr, 0, MAX_ADDR_LEN);
for(i = 1; i < argc; i++)
{
if(('/' == argv[i][0]) || ('-' == argv[i][1]))
{
switch(tolower(argv[i][1]))
{
case 'p':
nPort = atoi(&argv[i][3]);
break;
case 'i':
strcpy(szAddr, &argv[i][3]);
printf("%s", argv[i][3]);
break;
default:
usage();
break;
}
}
}
}

Windows下的编译命令为：

cl -o 服务器程序名称.exe 源文件名称.cpp WS2_32.lib

客户端编译同上，只是修改文件名即可。