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<concept id="GUID-70339E6A-63CD-5A74-846C-50771FDAC763" xml:lang="en"><title>Listening

for incoming Bluetooth connections</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This document describes how a Bluetooth device can allow incoming remote

device connections. </p>

<p>Incoming Bluetooth connection examples include: </p>

<ul>

<li id="GUID-F1021810-A06F-5549-837A-3C8B2D99BC19"><p>one end of a chat application, </p> </li>

<li id="GUID-C9417947-7464-5AD2-9DF0-5EC906CF1441"><p>the Audio Gateway role

in HSP (licensee), </p> </li>

<li id="GUID-8662B773-47E0-5C38-B88C-FE18F3370757"><p>or the Gateway in DUNP

(licensee). </p> </li>

</ul>

<p>Incoming requests for a Bluetooth connection are handled through the <xref href="GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0.dita"><apiname>RSocket</apiname></xref> API

(as with outgoing connections). </p>

<p>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. </p>

<section><title>How to set up an incoming connection</title><p>The steps are

given below:</p><p><b>Get a connection</b></p><p>Connect to the Sockets Server

and select the protocol to be used. </p><codeblock xml:space="preserve">RSocketServ socketServ;

socketServ.Connect();

_LIT(KL2Cap, "L2CAP"); // or RFCOMM as appropriate</codeblock><p><b>Open a

socket</b></p><p> Open a socket for that protocol. </p><codeblock xml:space="preserve">RSocket listen;

listen.Open(socketServ,KL2Cap);</codeblock><p><b>Create the Bluetooth socket

address</b></p><p> Create a Bluetooth socket address object (<xref href="GUID-DFE19A3C-9E18-3B27-8748-FA0DB48A599C.dita"><apiname>TBTSockAddr</apiname></xref>)

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. </p><codeblock xml:space="preserve">TBTSockAddr addr;

addr.SetPort(KListeningPSM);

User::LeaveIfError(listen.Bind(addr));</codeblock><p><b>Register with the

Bluetooth security manager</b></p><p>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. 

</p><codeblock xml:space="preserve">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);</codeblock><p>The security profile is created

and packaged in serviceSecurity and

applied using <xref href="GUID-D536FA83-2535-3BF2-AC0D-EA0C7CA806BA.dita#GUID-D536FA83-2535-3BF2-AC0D-EA0C7CA806BA/GUID-026CE232-E988-3C7E-A01D-6C70A3CCFC63"><apiname>RBTSecuritySettings::RegisterService()</apiname></xref>. The

 security profile overrides the default security settings thereby allowing

   incoming connections. </p><p><b>Add to the Bluetooth Service Discovery

Database</b></p><p>Enter record into the database. 

<codeblock xml:space="preserve">RSdpDatabase sdprec;

TSdpServRecordHandle recordHandle = 0;

sdprec.CreateServiceRecordL(*UUIDlist, recordHandle);

</codeblock></p><p><b>Start listening for connections</b></p>  Tell the socket

to listen for incoming connections using <xref href="GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0.dita#GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0/GUID-5360AE38-877F-3F9C-971C-4BCE781B5735"><apiname>RSocket::Listen()</apiname></xref>.

<p><codeblock xml:space="preserve">User::LeaveIfError(listen.Listen(2));</codeblock></p><p><b>Start

listening for data over a connection</b></p> Create a blank socket and pass

it to the listening socket through

<xref href="GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0.dita#GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0/GUID-3D6737DD-447F-323D-9466-0B910A1FFC6A"><apiname>RSocket::Accept()</apiname></xref>. 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.<codeblock xml:space="preserve">RSocket accept;

TRequestStatus status;

User::LeaveIfError(accept.Open(socketServ));

listen.Accept(accept,status);

User::WaitForRequest(status);</codeblock><p><b>Shutdown remote Bluetooth connection</b></p><p>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. 

</p><codeblock xml:space="preserve">accept.Close();

listen.Close();

secset.UnregisterService(KSolBtL2CAP, status);

socketServ.Close();</codeblock><p>The socket server is closed using the

<codeph>RHandleBase::Close()</codeph> method. It will close the handle to

the socket server and destroy it if there are no other referencing objects.

</p></section>

<section><title>Notes</title><p>If the channel is already in use, as indicated

if <codeph>Bind()</codeph> returns an error, you can find a free channel using

the <xref href="GUID-6BFA5331-7860-313B-97A8-7A61562CEE38.dita"><apiname>KRFCOMMGetAvailableServerChannel</apiname></xref> ioctl. </p><p>Also

search the Symbian DevNet for white papers and example applications. </p></section>

<section><title>Finding more...</title><p>  For more information on: </p><ul>

<li><p> setting security requirements for incoming connections to the service,

see [xref href="GUID-A035B592-F423-5980-8E7E-E726CF24CF3E"]Using Bluetooth

Security Manager[/xref]</p></li>

<li><p> advertising the service's availability, see [xref href="GUID-756D831F-F302-594C-8116-144358DD8442"]Using

Bluetooth Service Discovery Database[/xref]</p></li>

</ul></section>

<section><title>Where Next?</title> <p>This tutorial set takes you through

all the steps involved in setting up and communicating over a Bluetooth connection. </p> <ul>

<li id="GUID-3B52879B-627A-5E83-975F-3DC741739E28"><p> <b>Listening for Incoming

Bluetooth Connections</b> - This document </p> </li>

<li id="GUID-8BA24558-70C1-562C-8A18-129958685E79"><p> <xref href="GUID-834BD3BB-B39C-5EE9-8A62-9DC435930F95.dita">Handling

the Local Device Name</xref>  </p> </li>

<li id="GUID-3E74535E-235C-5DF2-9438-101BA38F8ACB"><p> <xref href="GUID-FDA7B932-B9C6-502D-8699-C18C8D86BCC6.dita">Performing

Low-level Configuration</xref>  </p> </li>

<li id="GUID-431BDE6E-163A-5F9F-93CE-B945A25AF649"><p> <xref href="GUID-5C63EF5C-826D-5838-BB7E-12FF4EA1DFCE.dita">Debugging

the Host Controller</xref>  </p> </li>

<li id="GUID-979AE36E-8A4C-500B-B600-DBB8E589C33E"><p> <xref href="GUID-01A0682A-50B1-57AB-9939-6CC8FCCD782D.dita">Disconnecting

ACL links</xref>  </p> </li>

</ul> </section>