TCP/IP 网络数据封包和解包

#pragma once

#define NET_PACKET_DATA_SIZE 1024
#define NET_PACKET_SIZE (sizeof(NetPacketHeader) + NET_PACKET_DATA_SIZE) * 10

/// 网络数据包包头
struct NetPacketHeader
{
unsigned short		wDataSize;	///< 数据包大小，包含封包头和封包数据大小
unsigned short		wOpcode;	///< 操作码
};

/// 网络数据包
struct NetPacket
{
NetPacketHeader		Header;							///< 包头
unsigned char		Data[NET_PACKET_DATA_SIZE];		///< 数据
};

//////////////////////////////////////////////////////////////////////////

/// 网络操作码
enum eNetOpcode
{
NET_TEST1			= 1,
};

/// 测试1的网络数据包定义
struct NetPacket_Test1
{
int		nIndex;
char name[20];
char sex[20];
int age;
char	arrMessage[512];
};

#pragma once

class TCPServer
{
public:
TCPServer();
virtual ~TCPServer();

public:
void run();

/// 接受客户端接入
void acceptClient();

/// 关闭客户端
void closeClient();

/// 发送数据
bool SendData(unsigned short nOpcode, const char* pDataBuffer, const unsigned int& nDataSize);

private:
SOCKET		mServerSocket;	///< 服务器套接字句柄
sockaddr_in	mServerAddr;	///< 服务器地址

SOCKET		mAcceptSocket;	///< 接受的客户端套接字句柄
sockaddr_in	mAcceptAddr;	///< 接收的客户端地址

char		m_cbSendBuf[NET_PACKET_SIZE];
};

#include "stdafx.h"

TCPServer::TCPServer()
: mServerSocket(INVALID_SOCKET)
{
// 创建套接字
mServerSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
if (mServerSocket == INVALID_SOCKET)
{
std::cout << "创建套接字失败!" << std::endl;
return;
}

// 填充服务器的IP和端口号
mServerAddr.sin_family		= AF_INET;
mServerAddr.sin_addr.s_addr	= INADDR_ANY;
mServerAddr.sin_port		= htons((u_short)SERVER_PORT);

// 绑定IP和端口
if ( ::bind(mServerSocket, (sockaddr*)&mServerAddr, sizeof(mServerAddr)) == SOCKET_ERROR)
{
std::cout << "绑定IP和端口失败!" << std::endl;
return;
}

// 监听客户端请求,最大同时连接数设置为10.
if ( ::listen(mServerSocket, SOMAXCONN) == SOCKET_ERROR)
{
std::cout << "监听端口失败!" << std::endl;
return;
}

std::cout << "启动TCP服务器成功!" << std::endl;
}

TCPServer::~TCPServer()
{
::closesocket(mServerSocket);
std::cout << "关闭TCP服务器成功!" << std::endl;
}

void TCPServer::run()
{
// 接收客户端的连接
acceptClient();

int nCount = 0;
for (;;)
{
if (mAcceptSocket == INVALID_SOCKET)
{
std::cout << "客户端主动断开了连接！" << std::endl;
break;
}

// 发送数据包
NetPacket_Test1 msg;//消息类型
msg.nIndex = nCount;
msg.age=23;
strncpy(msg.arrMessage, "北京市朝阳区", sizeof(msg.arrMessage) );
strncpy(msg.name, "天策", sizeof(msg.name) );
strncpy(msg.sex, "男", sizeof(msg.sex) );

bool bRet = SendData(NET_TEST1, (const char*)&msg, sizeof(msg));//强制类型转换为字符串类型
if (bRet)
{
std::cout << "发送数据成功！" << std::endl;
}
else
{
std::cout << "发送数据失败！" << std::endl;
break;
}

++nCount;
}
}

void TCPServer::closeClient()
{
// 判断套接字是否有效
if (mAcceptSocket == INVALID_SOCKET) return;

// 关闭客户端套接字
::closesocket(mAcceptSocket);
std::cout << "客户端套接字已关闭!" << std::endl;
}

void TCPServer::acceptClient()
{
// 以阻塞方式,等待接收客户端连接
int nAcceptAddrLen = sizeof(mAcceptAddr);
mAcceptSocket = ::accept(mServerSocket, (struct sockaddr*)&mAcceptAddr, &nAcceptAddrLen);
std::cout << "接受客户端IP:" << inet_ntoa(mAcceptAddr.sin_addr) << std::endl;
}

bool TCPServer::SendData( unsigned short nOpcode, const char* pDataBuffer, const unsigned int& nDataSize )
{
NetPacketHeader* pHead = (NetPacketHeader*) m_cbSendBuf;
pHead->wOpcode = nOpcode;//操作码

// 数据封包
if ( (nDataSize > 0) && (pDataBuffer != 0) )
{
CopyMemory(pHead+1, pDataBuffer, nDataSize);
}

// 发送消息
const unsigned short nSendSize = nDataSize + sizeof(NetPacketHeader);//包的大小事发送数据的大小加上包头大小
pHead->wDataSize = nSendSize;//包大小
int ret = ::send(mAcceptSocket, m_cbSendBuf, nSendSize, 0);
return (ret > 0) ? true : false;
}

// testTCPServer.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"

int _tmain(int argc, _TCHAR* argv[])
{
TCPServer server;
server.run();

system("pause");
return 0;
}

#pragma once

class TCPClient
{
public:
TCPClient();
virtual ~TCPClient();

public:
/// 主循环
void run();

/// 处理网络消息
bool OnNetMessage(const unsigned short& nOpcode,
const char* pDataBuffer, unsigned short nDataSize);

bool OnNetPacket(NetPacket_Test1* pMsg);

private:
SOCKET				mServerSocket;	///< 服务器套接字句柄
sockaddr_in			mServerAddr;	///< 服务器地址

char				m_cbRecvBuf[NET_PACKET_SIZE];
char				m_cbDataBuf[NET_PACKET_SIZE];
int					m_nRecvSize;
};

#include "stdafx.h"

TCPClient::TCPClient()
{
memset( m_cbRecvBuf, 0, sizeof(m_cbRecvBuf) );
m_nRecvSize = 0;

// 创建套接字
mServerSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
if (mServerSocket == INVALID_SOCKET)
{
std::cout << "创建套接字失败!" << std::endl;
return;
}

// 填充服务器的IP和端口号
mServerAddr.sin_family		= AF_INET;
mServerAddr.sin_addr.s_addr	= inet_addr(SERVER_IP);
mServerAddr.sin_port		= htons((u_short)SERVER_PORT);

// 连接到服务器
if ( ::connect(mServerSocket, (struct sockaddr*)&mServerAddr, sizeof(mServerAddr)))
{
::closesocket(mServerSocket);
std::cout << "连接服务器失败!" << std::endl;
return;
}
}

TCPClient::~TCPClient()
{
::closesocket(mServerSocket);
}

void TCPClient::run()
{
int nCount = 0;
for (;;)
{
// 接收数据
int nRecvSize = ::recv(mServerSocket,
m_cbRecvBuf+m_nRecvSize,
sizeof(m_cbRecvBuf)-m_nRecvSize, 0);
if (nRecvSize <= 0)
{
std::cout << "服务器主动断开连接!" << std::endl;
break;
}

// 保存已经接收数据的大小
m_nRecvSize += nRecvSize;

// 接收到的数据够不够一个包头的长度
while (m_nRecvSize >= sizeof(NetPacketHeader))//已经收到一个完整的包，如果没用收到一个完整的包，此处循环不执行，继续下一轮循环
{
// 收够5个包，主动与服务器断开
if (nCount >= 5)
{
::closesocket(mServerSocket);
break;
}

// 读取包头
NetPacketHeader* pHead = (NetPacketHeader*) (m_cbRecvBuf);
const unsigned short nPacketSize = pHead->wDataSize;

// 判断是否已接收到足够一个完整包的数据
if (m_nRecvSize < nPacketSize)
{
// 还不够拼凑出一个完整包
break;
}

// 拷贝到数据缓存
CopyMemory(m_cbDataBuf, m_cbRecvBuf, nPacketSize);

// 从接收缓存移除
MoveMemory(m_cbRecvBuf, m_cbRecvBuf+nPacketSize, m_nRecvSize);
m_nRecvSize -= nPacketSize;

// 解密数据，以下省略一万字
// ...

// 分派数据包，让应用层进行逻辑处理
pHead = (NetPacketHeader*) (m_cbDataBuf);
const unsigned short nDataSize = nPacketSize - (unsigned short)sizeof(NetPacketHeader);
OnNetMessage(pHead->wOpcode, m_cbDataBuf+sizeof(NetPacketHeader), nDataSize);

++nCount;
}
}

std::cout << "已经和服务器断开连接!" << std::endl;
}

bool TCPClient::OnNetMessage( const unsigned short& nOpcode,
const char* pDataBuffer, unsigned short nDataSize )
{
switch (nOpcode)
{
case NET_TEST1:
{
NetPacket_Test1* pMsg = (NetPacket_Test1*) pDataBuffer;
return OnNetPacket(pMsg);
}
break;

default:
{
std::cout << "收取到未知网络数据包:" << nOpcode << std::endl;
return false;
}
break;
}
}

bool TCPClient::OnNetPacket( NetPacket_Test1* pMsg )
{
std::cout << "索引：" << pMsg->nIndex << "  字符串：" << pMsg->arrMessage <<"name:"<<pMsg->name<<"sex:"<<pMsg->sex<<"age:"<<pMsg->age<< std::endl;
return true;
}

#include "stdafx.h"

int _tmain(int argc, _TCHAR* argv[])
{
TCPClient client;
client.run();

system("pause");
return 0;
}