WinSock网络编程经络----读书笔记(1)

一、echo客户/服务器程序

1、网络结构模型

a、集中式系统----有一个大型的中央处理系统，有点是数据容易备份，不易感染病毒，日常生活中的ATM、POS等使用的都是集中式系统

b、分布式系统----具有高度的可靠性、均衡负载、满足不同的需要

c、对等网络模型----P2P网络，每一台主机处于同等地位，既作为客户端，又充当其他主机的服务器，有可非为无结构网络、有结构网络、混合式网络、集中式网络

2、echo客户程序

mySocketClient.cpp：

#include "stdafx.h"
#include "winsock2.h"
#include "iostream"
#pragma comment(lib, "ws2_32")

#define ECHO_DEF_PORT	7	//连接的默认端口
#define ECHO_BUF_SIZE	256	//缓冲区的大小

#define InitSockets()	{				\
	WORD	version;					\
	WSADATA wsaData;					\
	version = MAKEWORD( 2,0 );			\
	WSAStartup(version, &wsaData);	}

#define	CleanupSockets()	WSACleanup()

void DoSoming()
{
	SOCKET echoSoc = 0;
	struct sockaddr_in servAddr;
	unsigned short port = ECHO_DEF_PORT;
	int result	= 0;
	int sendLen = 0;
	char *testSendData = "hello world";
	char recv_buf[ECHO_BUF_SIZE];

	sendLen = strlen(testSendData);

	servAddr.sin_family = AF_INET;
	servAddr.sin_port = htons(port);
	servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

	if (servAddr.sin_addr.s_addr == INADDR_NONE)
	{
		std::cout << "[ECHO] invalid address" << WSAGetLastError() << std::endl;
		exit(-1);
	}

	echoSoc = socket(AF_INET, SOCK_STREAM, 0);
	result = connect(echoSoc, (struct sockaddr *)&servAddr, sizeof(servAddr));

	if (result == 0)
	{
		result = send(echoSoc, testSendData, sendLen, 0);
		result = recv(echoSoc, recv_buf, ECHO_BUF_SIZE, 0);
	}

	if (result > 0)
	{
		recv_buf[result] = 0;
		std::cout << "[Echo Client] receives : " << recv_buf << std::endl;
	}
	else
	{
		std::cout << "[Echo Client] error : " << WSAGetLastError() << std::endl;
	}

	closesocket(echoSoc);
	CleanupSockets();
}

int _tmain(int argc, _TCHAR* argv[])
{
	DoSoming();

	return 0;
}

3、echo服务器程序

mySokcetSer.cpp：

#include "stdafx.h"
#include "winsock2.h"
#include "iostream"
#pragma comment(lib, "ws2_32")

#define ECHO_DEF_PORT	7	//连接的默认端口
#define ECHO_BUF_SIZE	256	//缓冲区的大小

#define InitSockets()	{				\
	WORD	version;					\
	WSADATA wsaData;					\
	version = MAKEWORD( 2,0 );			\
	WSAStartup(version, &wsaData);	}

#define	CleanupSockets()	WSACleanup()

void DoSoming()
{
	SOCKET	echoSoc = 0;
	SOCKET	acptSoc = 0;

	struct sockaddr_in servAddr;
	struct sockaddr_in clntAddr;

	unsigned short port = ECHO_DEF_PORT;
	int result = 0;
	int addrLen = sizeof(struct sockaddr_in);
	char recvBuf[ECHO_BUF_SIZE];

	echoSoc = socket(AF_INET, SOCK_STREAM, 0);

	servAddr.sin_family = AF_INET;
	servAddr.sin_port = htons(port);
	servAddr.sin_addr.s_addr = INADDR_ANY;

	result = bind(echoSoc, (struct sockaddr *)&servAddr, sizeof(servAddr));
	if (result == SOCKET_ERROR)
	{
		std::cout << "[Echo Server] bind error : " << WSAGetLastError() << std::endl;
		closesocket(echoSoc);
		exit(-1);
	}

	listen(echoSoc, SOMAXCONN);

	std::cout << "[Echo Server] is running ... ..." << std::endl;
	while (true)
	{
		acptSoc = accept(echoSoc, (struct sockaddr *)&clntAddr, &addrLen);
		if (acptSoc == INVALID_SOCKET)
		{
			std::cout << "[Echo Server] bind error : " << WSAGetLastError() << std::endl;
			break;
		}

		result = recv(acptSoc, recvBuf, ECHO_BUF_SIZE, 0);
		if (result > 0)
		{
			recvBuf[result] = 0;
			std::cout << "[Echo Server] receives : " << recvBuf << "from : " 
					  << inet_ntoa(clntAddr.sin_addr) << std::endl;

			result = send(acptSoc, recvBuf, result, 0);
		}

		closesocket(acptSoc);
	}

	closesocket(acptSoc);
	CleanupSockets();
}

int _tmain(int argc, _TCHAR* argv[])
{
	DoSoming();

	return 0;
}