Question

我想了解更多关于通过互联网发送数据的信息。我一直在寻找很多，但没有任何帮助...... 我正在使用MinGw，请不要说我必须改变我的开发者计划。到目前为止，我从我发现的内容中做到了：它工作得很好但仅适用于我的本地网络。谁能告诉我如何才能通过互联网做同样的事情？

using namespace std;
#pragma once
#include <iostream>
#include "WinSock2.h"
const int STRLEN = 256;

class Socket
{
    protected:
        WSADATA wsaData;
        SOCKET mySocket;
        SOCKET myBackup;
        SOCKET acceptSocket;
        sockaddr_in myAddress;
    public:
        Socket();
        ~Socket();
        bool SendData( char* );
        bool RecvData( char*, int );
        void CloseConnection();
        void GetAndSendMessage();
};

class ServerSocket : public Socket
{
    public:
        void Listen();
        void Bind( int port );
        void StartHosting( int port );
};

class ClientSocket : public Socket
{
    public:
        void ConnectToServer( const char *ipAddress, int port );
};


Socket::Socket()
{
    if( WSAStartup( MAKEWORD(2, 2), &wsaData ) != NO_ERROR )
    {
        cerr<<"Socket Initialization: Error with WSAStartup\n";
        system("pause");
        WSACleanup();
        exit(10);
    }

    //Create a socket
    mySocket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );

    if ( mySocket == INVALID_SOCKET )
    {
        cerr<<"Socket Initialization: Error creating socket"<<endl;
        system("pause");
        WSACleanup();
        exit(11);
    }

    myBackup = mySocket;
}

Socket::~Socket()
{
    WSACleanup();
}

bool Socket::SendData( char *buffer )
{
    send( mySocket, buffer, strlen( buffer ), 0 );
    return true;
}

bool Socket::RecvData( char *buffer, int size )
{
    int i = recv( mySocket, buffer, size, 0 );
    buffer[i] = '\0';
    return true;
}

void Socket::CloseConnection()
{
    //cout<<"CLOSE CONNECTION"<<endl;
    closesocket( mySocket );
    mySocket = myBackup;
}

void Socket::GetAndSendMessage()
{
    char message[STRLEN];
    cin.ignore();//without this, it gets the return char from the last cin and ignores the following one!
    cout<<"Send > ";
    cin.get( message, STRLEN );
    SendData( message );
}

void ServerSocket::StartHosting( int port )
{
     Bind( port );
     Listen();
}

void ServerSocket::Listen()
{
    //cout<<"LISTEN FOR CLIENT..."<<endl;

    if ( listen ( mySocket, 1 ) == SOCKET_ERROR )
    {
        cerr<<"ServerSocket: Error listening on socket\n";
        system("pause");
        WSACleanup();
        exit(15);
    }

    //cout<<"ACCEPT CONNECTION..."<<endl;

    acceptSocket = accept( myBackup, NULL, NULL );
    while ( acceptSocket == SOCKET_ERROR )
    {
        acceptSocket = accept( myBackup, NULL, NULL );
    }
    mySocket = acceptSocket;
}

void ServerSocket::Bind( int port )
{
    myAddress.sin_family = AF_INET;
    myAddress.sin_addr.s_addr = inet_addr( "0.0.0.0" );
    myAddress.sin_port = htons( port );

    //cout<<"BIND TO PORT "<<port<<endl;

    if ( bind ( mySocket, (SOCKADDR*) &myAddress, sizeof( myAddress) ) == SOCKET_ERROR )
    {
        cerr<<"ServerSocket: Failed to connect\n";
        system("pause");
        WSACleanup();
        exit(14);
    }
}

void ClientSocket::ConnectToServer( const char *ipAddress, int port )
{
    myAddress.sin_family = AF_INET;
    myAddress.sin_addr.s_addr = inet_addr( ipAddress );
    myAddress.sin_port = htons( port );

    //cout<<"CONNECTED"<<endl;

    if ( connect( mySocket, (SOCKADDR*) &myAddress, sizeof( myAddress ) ) == SOCKET_ERROR )
    {
        cerr<<"ClientSocket: Failed to connect\n";
        system("pause");
        WSACleanup();
        exit(13);
    } 
}

int main()
{
    int choice;
    int port = 666;
    //char *ipAddress = "127.0.0.1";
    string ipAddress;
    bool done = false;
    char recMessage[STRLEN];
    char sendMessage[STRLEN];
    cout<<"1) Host server"<<endl;
    cout<<"2) Join server"<<endl;
    cout<<"3) Quit"<<endl;
    cin>>choice;
    if ( choice == 3 )
        exit(0);
    else if ( choice == 2 )
    {
        //Client
        cout<<"Enter an IP address, 127.0.0.1 is the loopback address"<<endl;
        cin>>ipAddress;
        ClientSocket sockClient;
        cout<<"ATTEMPTING TO CONNECT..."<<endl;
        sockClient.ConnectToServer( ipAddress.c_str(), port );
        //Connected
        while ( !done )
        {     
            sockClient.GetAndSendMessage();
            cout<<"\t--WAIT--"<<endl;
            sockClient.RecvData( recMessage, STRLEN );
            cout<<"Recv > "<<recMessage<<endl;
            if ( strcmp( recMessage, "end" ) == 0 ||
                        strcmp( sendMessage, "end" ) == 0 )
            {
                done = true;
            }
        }
        sockClient.CloseConnection();
    }
    else if ( choice == 1 )
    {
        //SERVER
        ServerSocket sockServer;
        cout<<"HOSTING..."<<endl;
        sockServer.StartHosting( port );
        //sockServer.StartHosting( port );
        //Connected
        while ( !done )
        {
            cout<<"\t--WAIT--"<<endl;
            sockServer.RecvData( recMessage, STRLEN );
            cout<<"Recv > "<<recMessage<<endl;
            sockServer.GetAndSendMessage();
            if ( strcmp( recMessage, "end" ) == 0 || strcmp( sendMessage, "end" ) == 0 )
            {
                done = true;
            }
        }
    }
}

感谢所有回复的人，但是当我问到应该更改代码的哪一部分以便我可以使用互联网时，你给了我很多东西。显然，我无法理解那里写的一半。仍然没有任何帮助。

Answer 1

如果您想通过互联网使用套接字并希望您的应用程序可以在每个网络设置（包括NAT）上使用，则必须使用TCP Holepunch调用技术（或UDP穿孔也适合）。我认为你的方法不起作用因为端点之间存在一些NAT，所以套接字连接失败。

我建议调查NAT。 Peer-to-Peer Communication Across Network Address Translators

this discussion here on SO

Answer 2

你有什么不明白的？我看到代码，它绑定到本地套接字然后用客户端连接到它。您也可以通过互联网进行此操作但是您不了解该过程的内容是什么？在尝试编写套接字代码之前，我担心您可能需要开始学习TCP / IP的基础知识。这就像试图通过建造航天飞机开始学习工程学一样。

Answer 3

托管从Internet可见的服务的能力非常依赖于您所拥有的Internet连接类型。如果您在NAT后面，则需要设置NAT端口转发。如果您的IP地址是动态的，则需要知道您公开的IP地址（尝试http://www.whatismyip.com/）。

C ++中的互联网套接字

3 个答案: