QT4에서 TCP 클라이언트의 IP 및 포트를 바인딩합니다. [bind QTcpSocket HOWTO]

 1 #ifndef Q_BOUND_TCP_SOCKET_H
 2 #define Q_BOUND_TCP_SOCKET_H
 3 
 4 #include <QTcpSocket>
 5 
 6 /**
 7  * \brief The QBoundTcpSocket class adds binding support
 8  * to tcp client sockets.
 9  *
10  * In Qt 4, it's impossible to bind a tcp client socket to
11  * a specific port or ip address.
12  *
13  * This feature has been added to Qt 5, however with version 4, 
14  * it's still possible to do binding while getting convenience from
15  * the Qt framework.
16  * 
17  * Note:
18  * 
19  * Due to usage of native api, the class currently not supports
20  * platforms other than Linux. If you are familiar with 
21  * native programming interfaces like winsock, porting the code
22  * to other operations systems may be just a piece of cake.
23  * 
24  * A QBoundTcpSocket object will bind and connect to the server
25  * at the same time, because the only way to work around is to
26  * create a socket, bind, connect to server with native API from the
27  * OS, and then pass the socket to QTcpSocket::setSocketDescriptor
28  * with a connected state.
29  */
30 
31 class QBoundTcpSocket : public QTcpSocket
32 {
33 public:
34     /**
35  * \brief Bind the socket and then connect to server
36  *
37  * Note:
38  * 
39  * Before calling, the socket must be in the unconnected state, 
40  * otherwise a value of false is returned.
41  * 
42  * Typical usage:
43  * \code
44  * QBoundTcpSocket socket;
45  * if (socket.bindAndConnect("192.168.1.10", 0, "10.0.0.1", 80))
46  * {
47  * // Now bound and connected
48  * }
49  * else
50  * {
51  * qDebug() << "An error occurred in QBoundTcpSocket::bindAndConnect";
52  * }
53  * \endcode
54  *
55  * \param localAddr Local IP address (e.g., "10.0.0.10").
56  * A value of "0.0.0.0" indicates that 
57  * the default ip address will be used.
58  * \param localPort Local port (e.g., 12345). 
59  * A value of 0 indicates that any port is acceptable.
60  * \param serverAddr IP address of the server (e.g., "10.0.0.1")
61  * \param serverPort Port of the server (e.g., 80)
62  *
63  * \return The return value is true when both binding and connecting 
64  * are successful, and false otherwise.
65 */
66      bool bindAndConnect(const QString &localAddr, quint16 localPort, 
67                          const QString &serverAddr, quint16 serverPort);
68 };
69 
70 #endif /* Q_BOUND_TCP_SOCKET_H */

 1 #include "QBoundTcpSocket.h"
 2 
 3 #ifdef Q_OS_LINUX
 4     #include <arpa/inet.h>
 5 #endif
 6 
 7 bool QBoundTcpSocket::bindAndConnect(const QString &localAddr, quint16 localPort, 
 8                                      const QString &serverAddr, quint16 serverPort)
 9 {
10 #ifdef Q_OS_LINUX
11     int sockfd;
12     int result;
13     struct sockaddr_in localSockAddr;
14     struct sockaddr_in serverSockAddr;
15     bzero(&localSockAddr, sizeof(localSockAddr));
16     bzero(&serverSockAddr, sizeof(serverSockAddr));
17     
18     // create socket
19     sockfd = socket(AF_INET, SOCK_STREAM, 0);
20     if( sockfd == -1 ) 
21     {
22         qDebug() << "QBoundTcpSocket: Cannot create socket";
23         return false;
24     }
25     
26     // bind
27     localSockAddr.sin_family = AF_INET;
28     localSockAddr.sin_port = htons(localPort);
29     localSockAddr.sin_addr.s_addr = inet_addr(localAddr.toLocal8Bit().data());
30 
31     result = bind(sockfd, (struct sockaddr *)&localSockAddr, sizeof(localSockAddr));
32     if( result == -1 ) 
33     {
34         qDebug() << "QBoundTcpSocket: Cannot bind socket";
35         return false;
36     }
37     
38     // connect
39     serverSockAddr.sin_family = AF_INET;
40     serverSockAddr.sin_port = htons(serverPort);
41     serverSockAddr.sin_addr.s_addr = inet_addr(serverAddr.toLocal8Bit().data());
42 
43     result = ::connect(sockfd, (struct sockaddr *)&serverSockAddr, sizeof(serverSockAddr));
44     if( result == -1 ) 
45     {
46         qDebug() << "QBoundTcpSocket: Cannot connect to server";
47         return false;
48     }
49     
50     // set socket descriptor
51     if( !setSocketDescriptor(sockfd, QAbstractSocket::ConnectedState))
52     {
53         qDebug() << "QBoundTcpSocket: Cannot set socket descriptor";
54         return false;
55     }
56     
57     return true;
58 #else
59     qDebug() << "QBoundTcpSocket for Windows/Mac OS is not implemented yet";
60     return false;
61 #endif
62 }