基于Windows Socket的安全通信(C++实现,附源码)-CFANZ编程社区

先了解一下Socket的相关函数原型

`//加载套接字库` `int` `PASCAL FAR WSAStartup(` `WORD` `wVersionRequired, LPWSADATA lpWSAData);` `//释放套接字库资源` `int` `PASCAL FAR WSACleanup(` `void` `);` `//创建套接字` `SOCKET PASCAL FAR socket (` `int` `af,` `int` `type,` `int` `protocol);` `//关闭套接字` `int` `PASCAL FAR closesocket (SOCKET s);` `//绑定一个IP地址和端口` `int` `PASCAL FAR bind (SOCKET s,` `const` `struct` `sockaddr FAR addr,` `int` `namelen);` `//将套接字置为监听状态` `int` `PASCAL FAR listen (SOCKET s,` `int` `backlog);` `//接受客户端连接请求，并返回新创建的套接字` `SOCKET PASCAL FAR accept (SOCKET s,` `struct` `sockaddr FAR addr,` `int` `FAR addrlen);` `//尝试将本地套接字连接至服务器` `int` `PASCAL FAR connect (SOCKET s,` `const` `struct` `sockaddr FAR name,` `int` `namelen);` `//发送数据` `int` `PASCAL FAR send (SOCKET s,` `const` `char` `FAR * buf,` `int` `len,` `int` `flags);` `//接收数据` `int` `PASCAL FAR recv (SOCKET s,` `char` `FAR * buf,` `int` `len,` `int` `flags);`

使用Socket的程序在使用Socket之前必须调用WSAStartup函数来绑定Socket库

在Constructor中添加如下代码

`int` `error;` `WORD` `wVersionRequested;` `WSADATA wsaData;` `wVersionRequested = MAKEWORD(2, 1);` `//加载2.1版本的Socket库` `if` `(error = WSAStartup(wVersionRequested, &wsaData))` `{` `AfxMessageBox(` `"Link Socket Library Failed!"` `);` `exit` `(0);` `}`

应用程序完成对Socket的使用后应当调用WSACleanup函数来释放Socket库占用的系统资源

在析构函数冲添加如下代码

`WSACleanup();`

Socket通信流程

实现安全通信，应采用面向连接的TCP/IP协议来保证连接的可靠性

面向连接的套接字的系统调用时序图

基于Windows Socket的安全通信(C++实现,附源码)_套接字

添加成员变量及初始化

`//服务器端：` 　　`SOCKET Listener,toClient;` `//用于监听的套接字和连接至客户端的套接字（只是为了实现通信模型，所以不考虑多客户端）` `bool` `listening, connected;` `//指示监听和连接的状态` 　　`AES aes;` `//加密/解密模块` `CTestSocketServerDlg::CTestSocketServerDlg(CWnd* pParent):` `CDialog(CTestSocketServerDlg::IDD, pParent),` `aes((unsigned` `char` `)` `"0123456789abcdef"` `),` `listening(` `false` `),` `connected(` `false` `)` `{` `//Constructor of Server` `}` `//客户端：` 　　`SOCKET toServer;` `//连接至服务器端的套接字` `bool` `connected;` `//指示连接状态` 　　`AES aes;` `//加密/解密模块` `CTestSocketClientDlg::CTestSocketClientDlg(CWnd pParent):` `CDialog(CTestSocketClientDlg::IDD, pParent),` `aes((unsigned` `char` `*)` `"0123456789abcdef"` `),` `connected(` `false` `)` `{` `//Constructor of Client` `}`

为“Start/Stop”按钮注册单击事件处理服务器端初始化及关闭操作

`void` `CTestSocketServerDlg::OnBtnStart()` `{` `if` `(connected \|\| listening)` `//若正在监听或已连接则关闭服务器` `{` `connected =` `false` `;` `listening =` `false` `;` `closesocket(toClient);` `closesocket(Listener);` `m_chat +=` `"Socket Server Stopped!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `UpdateData(` `true` `);` `//创建监听Socket` `struct` `protoent ppe;` `ppe = getprotobyname(` `"tcp"` `);` `if` `((Listener = socket(PF_INET, SOCK_STREAM, ppe->p_proto)) == INVALID_SOCKET)` `{` `m_chat +=` `"Initialize Socket Listener Failed!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `//绑定IP及端口` `struct` `sockaddr_in saddr;` `saddr.sin_family = AF_INET;` `saddr.sin_port = htons(m_port);` `saddr.sin_addr.s_addr = htonl(INADDR_ANY);` `if` `(bind(Listener, (` `struct` `sockaddr )&saddr,` `sizeof` `(saddr)))` `{` `m_chat +=` `"Bind to IPEndPoint Failed! (Port in use?)\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `//开始监听,队列长度1（不考虑多客户端）` `if` `(listen(Listener, 1))` `{` `m_chat +=` `"Listen Failed!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `m_chat +=` `"Socket Server Started!\r\n"` `;` `UpdateData(` `false` `);` `listening =` `true` `;` `AfxBeginThread(Wait4Client,` `this` `);` `//另起线程等待客户端连接` `}`

接收来自客户端的连接请求

`UINT` `Wait4Client(` `LPVOID` `pParam)` `{` `CTestSocketServerDlg * c = (CTestSocketServerDlg ) pParam;` `struct` `sockaddr_in caddr;` `int` `caddrlen =` `sizeof` `(caddr);` `c->toClient = accept(c->Listener, (` `struct` `sockaddr )&caddr, &caddrlen);` `if` `(c->toClient == INVALID_SOCKET)` `//异常处理` `{` `if` `(!c->listening)` `return` `0;` `//服务器端主动关闭，则直接退出` `c->m_chat +=` `"Connect Failed!\r\n"` `;` `c->UpdateData(` `false` `);` `return` `-1;` `}` `else` `{` `c->connected =` `true` `;` `//连接建立，另起线程用于接收信息` `AfxBeginThread(ReceiveMessage, c);` `c->m_chat +=` `"Client: "` `;` `c->m_chat += inet_ntoa(caddr.sin_addr);` `c->m_chat +=` `" Connected!\r\n"` `;` `c->m_ip = inet_ntoa(caddr.sin_addr);` `c->UpdateData(` `false` `);` `}` `return` `0;` `}`

客户端只需要创建Socket并尝试与服务器连接

为“Connect/Disconnect”按钮注册单击事件

`void` `CTestSocketClientDlg::OnBtnConnect()` `{` `if` `(connected)` `//如果已连接，则断开` `{` `connected =` `false` `;` `closesocket(toServer);` `m_chat +=` `"Disconnect to Server!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `UpdateData(` `true` `);` `//创建Socket` `struct` `protoent ppe;` `ppe = getprotobyname(` `"tcp"` `);` `if` `((toServer = socket(PF_INET, SOCK_STREAM, ppe->p_proto)) == INVALID_SOCKET)` `{` `m_chat +=` `"Initialize Socket Listener Failed!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `//尝试连接服务器` `struct` `sockaddr_in saddr;` `saddr.sin_family = AF_INET;` `saddr.sin_port = htons(m_port);` `saddr.sin_addr.s_addr = inet_addr(m_ip);` `if` `(connect(toServer, (` `struct` `sockaddr )&saddr,` `sizeof` `(saddr)))` `{` `m_chat +=` `"Connect Failed!\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `m_chat +=` `"Server: "` `;` `m_chat += inet_ntoa(saddr.sin_addr);` `m_chat +=` `" Connected!\r\n"` `;` `connected =` `true` `;` `UpdateData(` `false` `);` `AfxBeginThread(ReceiveMessage,` `this` `);` `//连接建立，另起线程用于接收信息` `}`

用于循环接收信息的线程

`UINT` `ReceiveMessage(` `LPVOID` `pParam)` `{` `CTestSocketServerDlg * c = (CTestSocketServerDlg ) pParam;` `char` `buffer[1024];` `int` `error;` `//记录recv函数返回值，即接收的字节数，也作异常代码` `while` `(error = recv(c->toClient, buffer, 1024, 0))` `{` `if` `(error == 0 \|\| error == SOCKET_ERROR)` `break` `;` `c->PrintData(` `"Received Data"` `, (unsigned` `char` `)buffer, error);` `c->aes.InvCipher((` `void` `)buffer, error);` `//解密，恢复明文` `c->PrintData(` `"Unencrypted Data"` `, (unsigned` `char` `)buffer, error);` `c->m_chat +=` `"Client:"` `;` `c->m_chat += buffer;` `c->m_chat +=` `"\r\n"` `;` `c->UpdateData(` `false` `);` `}` `c->m_ip =` `"Not Connected..."` `;` `c->UpdateData(` `false` `);` `if` `(!c->connected)` `return` `0;` `//服务器端主动关闭，直接返回` `closesocket(c->toClient);` `c->connected =` `false` `;` `c->m_chat +=` `"Client Disconnected...\r\n"` `;` `c->UpdateData(` `false` `);` `AfxBeginThread(Wait4Client, c);` `return` `0;` `}`

为“Send”按钮注册单击事件，处理数据的加密发送

`void` `CTestSocketServerDlg::OnBtnSend()` `{` `if` `(!connected)` `return` `;` `UpdateData(` `true` `);` `if` `(m_message ==` `""` `)` `return` `;` `int` `len = m_message.GetLength()+1 >= 1024 ? 1024 : m_message.GetLength()+1;` `len = len%16 ? len+16-len%16 : len;` `char` `buffer[1024];` `strcpy` `(buffer,m_message.GetBuffer(0));` `//将message拷贝至buffer数组中` `m_message.ReleaseBuffer();` `PrintData(` `"Input Data"` `, (unsigned` `char` `)buffer, len);` `aes.Cipher((` `void` `)buffer);` `//对数据进行加密` `if` `(send(toClient, buffer, len, 0) == SOCKET_ERROR)` `//发送密文` `{` `m_chat +=` `"Send Failed!(Socket Exception?)\r\n"` `;` `UpdateData(` `false` `);` `return` `;` `}` `PrintData(` `"Encrypted Data"` `, (unsigned` `char` `*)buffer, len);` `m_chat +=` `"Server:"` `+ m_message +` `"\r\n"` `;` `m_message =` `""` `;` `UpdateData(` `false` `);` `}`

发送和接收的时候都用到了一个函数PrintData,用于将明文或密文以16进制输出以便作演示

`void` `CTestSocketServerDlg::PrintData(` `char` `* title, unsigned` `char` `* buffer,` `int` `length)` `{` `int` `i;` `CString temp(` `""` `);` `m_chat +=` `"("` `;` `m_chat += title;` `m_chat +=` `":"` `;` `for` `(i=0; i<length; i++)` `{` `temp.Format(` `"%s%X "` `,(buffer+i)>15?` `""` `:` `"0"` `,(buffer+i));` `m_chat += temp;` `}` `m_chat +=` `")\r\n"` `;` `}`