Listening -for incoming Bluetooth connections

This document describes how a Bluetooth device can allow incoming remote -device connections.

Incoming Bluetooth connection examples include:

one end of a chat application,
the Audio Gateway role -in HSP (licensee),
or the Gateway in DUNP -(licensee).

Incoming requests for a Bluetooth connection are handled through the RSocket API -(as with outgoing connections).

To receive an incoming connection a service must open a listening socket, -register the socket with the Bluetooth security manager, and advertise the -socket, then connection requests can be accepted.

How to set up an incoming connection

The steps are -given below:

Get a connection

Connect to the Sockets Server -and select the protocol to be used.

RSocketServ socketServ; -socketServ.Connect(); -_LIT(KL2Cap, "L2CAP"); // or RFCOMM as appropriate

Open a -socket

Open a socket for that protocol.

RSocket listen; -listen.Open(socketServ,KL2Cap);

Create the Bluetooth socket -address

Create a Bluetooth socket address object (TBTSockAddr) -and set its port to the PSM or server channel (for L2CAP or RFCOMM respectively) -and bind the socket to this address. Note you do not have to set the local -Bluetooth device address in the address.

TBTSockAddr addr; -addr.SetPort(KListeningPSM); -User::LeaveIfError(listen.Bind(addr));

Register with the -Bluetooth security manager

Add the connection to the Bluetooth security -manager. Incoming -connections will not work unless they have been registered with the Bluetooth -security manager, thus allowing the incoming traffic through the security -wall, -which by default denies access to all connection attempts. -

RBTSecuritySettings secset; -TRequestStatus status; -TBTServiceSecurity serviceSecurity(aMyUid,KSolBtRFCOMM,aChannel); -serviceSecurity.SetAuthentication(EFalse); -serviceSecurity.SetEncryption(EFalse); -serviceSecurity.SetAuthorisation(EFalse); -serviceSecurity.SetDenied(EFalse); -User::LeaveIfError(secset.RegisterService(serviceSecurity, status)); -User::WaitForRequest(status); -test(status.Int()==KErrNone);

The security profile is created -and packaged in serviceSecurity and -applied using RBTSecuritySettings::RegisterService(). The - security profile overrides the default security settings thereby allowing - incoming connections.

Add to the Bluetooth Service Discovery -Database

Enter record into the database. -RSdpDatabase sdprec; -TSdpServRecordHandle recordHandle = 0; -sdprec.CreateServiceRecordL(*UUIDlist, recordHandle); -

Start listening for connections

Tell the socket -to listen for incoming connections using RSocket::Listen(). - -

User::LeaveIfError(listen.Listen(2));

Start -listening for data over a connection

Create a blank socket and pass -it to the listening socket through -RSocket::Accept(). When this call completes, the socket -passed in a parameter is now fully connected and can be used to send and receive -data. The listening socket remains in place, ready for another socket to be -passed in when the program can handle another connection.RSocket accept; -TRequestStatus status; -User::LeaveIfError(accept.Open(socketServ)); -listen.Accept(accept,status); -User::WaitForRequest(status);

Shutdown remote Bluetooth connection

Shutdown -connection and unregister security settings. When the -receiver wishes to shutdown, it must ensure that it closes the listening socket - as well as any connected ones. This releases the Bluetooth connection to -other -applications. -

accept.Close(); -listen.Close(); -secset.UnregisterService(KSolBtL2CAP, status); -socketServ.Close();

The socket server is closed using the -RHandleBase::Close() method. It will close the handle to -the socket server and destroy it if there are no other referencing objects. - -

Notes

If the channel is already in use, as indicated -if Bind() returns an error, you can find a free channel using -the KRFCOMMGetAvailableServerChannel ioctl.

Also -search the Symbian DevNet for white papers and example applications.

Finding more...

For more information on:

setting security requirements for incoming connections to the service, -see [xref href="GUID-A035B592-F423-5980-8E7E-E726CF24CF3E"]Using Bluetooth -Security Manager[/xref]
advertising the service's availability, see [xref href="GUID-756D831F-F302-594C-8116-144358DD8442"]Using -Bluetooth Service Discovery Database[/xref]

Where Next?

This tutorial set takes you through -all the steps involved in setting up and communicating over a Bluetooth connection.

Listening for Incoming -Bluetooth Connections - This document
Handling -the Local Device Name
Performing -Low-level Configuration
Debugging -the Host Controller
Disconnecting -ACL links

+ + + + + +Listening +for incoming Bluetooth connections +

This document describes how a Bluetooth device can allow incoming remote +device connections.

Incoming Bluetooth connection examples include:

one end of a chat application,
the Audio Gateway role +in HSP (licensee),
or the Gateway in DUNP +(licensee).

Incoming requests for a Bluetooth connection are handled through the RSocket API +(as with outgoing connections).

To receive an incoming connection a service must open a listening socket, +register the socket with the Bluetooth security manager, and advertise the +socket, then connection requests can be accepted.

How to set up an incoming connection

The steps are +given below:

Get a connection

Connect to the Sockets Server +and select the protocol to be used.

RSocketServ socketServ; +socketServ.Connect(); +_LIT(KL2Cap, "L2CAP"); // or RFCOMM as appropriate

Open a +socket

Open a socket for that protocol.

RSocket listen; +listen.Open(socketServ,KL2Cap);

Create the Bluetooth socket +address

Create a Bluetooth socket address object (TBTSockAddr) +and set its port to the PSM or server channel (for L2CAP or RFCOMM respectively) +and bind the socket to this address. Note you do not have to set the local +Bluetooth device address in the address.

TBTSockAddr addr; +addr.SetPort(KListeningPSM); +User::LeaveIfError(listen.Bind(addr));

Register with the +Bluetooth security manager

Add the connection to the Bluetooth security +manager. Incoming +connections will not work unless they have been registered with the Bluetooth +security manager, thus allowing the incoming traffic through the security +wall, +which by default denies access to all connection attempts. +

RBTSecuritySettings secset; +TRequestStatus status; +TBTServiceSecurity serviceSecurity(aMyUid,KSolBtRFCOMM,aChannel); +serviceSecurity.SetAuthentication(EFalse); +serviceSecurity.SetEncryption(EFalse); +serviceSecurity.SetAuthorisation(EFalse); +serviceSecurity.SetDenied(EFalse); +User::LeaveIfError(secset.RegisterService(serviceSecurity, status)); +User::WaitForRequest(status); +test(status.Int()==KErrNone);

The security profile is created +and packaged in serviceSecurity and +applied using RBTSecuritySettings::RegisterService(). The + security profile overrides the default security settings thereby allowing + incoming connections.

Add to the Bluetooth Service Discovery +Database

Enter record into the database. +RSdpDatabase sdprec; +TSdpServRecordHandle recordHandle = 0; +sdprec.CreateServiceRecordL(*UUIDlist, recordHandle); +

Start listening for connections

Tell the socket +to listen for incoming connections using RSocket::Listen(). + +

User::LeaveIfError(listen.Listen(2));

Start +listening for data over a connection

Create a blank socket and pass +it to the listening socket through +RSocket::Accept(). When this call completes, the socket +passed in a parameter is now fully connected and can be used to send and receive +data. The listening socket remains in place, ready for another socket to be +passed in when the program can handle another connection.RSocket accept; +TRequestStatus status; +User::LeaveIfError(accept.Open(socketServ)); +listen.Accept(accept,status); +User::WaitForRequest(status);

Shutdown remote Bluetooth connection

Shutdown +connection and unregister security settings. When the +receiver wishes to shutdown, it must ensure that it closes the listening socket + as well as any connected ones. This releases the Bluetooth connection to +other +applications. +

accept.Close(); +listen.Close(); +secset.UnregisterService(KSolBtL2CAP, status); +socketServ.Close();

The socket server is closed using the +RHandleBase::Close() method. It will close the handle to +the socket server and destroy it if there are no other referencing objects. + +

Notes

If the channel is already in use, as indicated +if Bind() returns an error, you can find a free channel using +the KRFCOMMGetAvailableServerChannel ioctl.

Also +search the Symbian DevNet for white papers and example applications.

Finding more...

For more information on:

setting security requirements for incoming connections to the service, +see [xref href="GUID-A035B592-F423-5980-8E7E-E726CF24CF3E"]Using Bluetooth +Security Manager[/xref]
advertising the service's availability, see [xref href="GUID-756D831F-F302-594C-8116-144358DD8442"]Using +Bluetooth Service Discovery Database[/xref]

Where Next?

This tutorial set takes you through +all the steps involved in setting up and communicating over a Bluetooth connection.

Listening for Incoming +Bluetooth Connections - This document
Handling +the Local Device Name
Performing +Low-level Configuration
Debugging +the Host Controller
Disconnecting +ACL links

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