How to Create an Explicitly Bound Socket

This topic describes how create an explicitly bound socket.

Start the network interface connection with RConnection::Start() to create an explicitly bound socket.

Creating an explicitly bound socket

Explicitly bound sockets can be created in two ways:

Open a socket and bind the socket to a network interface connection.
- Call RSocket::Open() and pass an RConnection.
  
  RConnection binds to an interface corresponding to the RConnection.
  
  In the following example code, if iConn corresponds to a WiFi RConnection then, after a calling RSocket::Open() the socket is explicitly bound to WiFi.
```
iRecvSock.Open( ss, KAfInet, KSockStream, KProtocolInetTcp, iConn );
```

Open a socket and bind the socket to an IP address of the network interface connection.

Call RSocket::Bind() and bind the socket to an IP address of the network interface connection.

RSocket::Bind() binds the socket to a unique IP address of the network interface connection.

The following example code shows how to open a socket and bind the socket to a unique IP address of the WiFi connection.

// open an implicit socket
TInt err = iRecvSock.Open( iSs, KAfInet, KSockDatagram, KProtocolInetUdp); 
User::LeaveIfError( err );
// This IP address maps to WiFi in the ced.cfg file
_LIT(KRasAddr,"192.168.220.4");
const TInt KPort = 7000;
TInetAddr addr;
err = addr.Input( KRasAddr ); 
User::LeaveIfError( err );
addr.SetPort( KPort );
// Now the socket is explicitly bound to WiFi  
err = iRecvSock.Bind( addr ); 
RDebug::Print( _L("testapp: ETH Bind() = %d"), err ); 
User::LeaveIfError( err );

The following code block shows an extract from the ced.cfg file.

## 
[LANService]
ADD_SECTION
# COMMDB_ID = 1
Name=Ethernet
IfNetworks=ip
IpNetMask=255.0.0.0
IpGateway=0.0.0.0
IpAddrFromServer=FALSE
IpAddr=192.168.1.1
IpDNSAddrFromServer=FALSE
ConfigDaemonManagerName=NetCfgExtnDhcp
ConfigDaemonName=!DhcpServ
FIELD_COUNT=9
END_ADD

ADD_SECTION
# COMMDB_ID = 2
Name=Ethernet WiFi
IfNetworks=ip
IpNetMask=255.0.0.0
IpGateway=0.0.0.0
IpAddrFromServer=FALSE
-// This IP address maps to WiFi
IpAddr=192.168.220.4
IpDNSAddrFromServer=FALSE
IpNameServer1=194.72.6.51
IpNameServer2=194.72.6.52
ConfigDaemonManagerName=NetCfgExtnDhcp
ConfigDaemonName=!DhcpServ
LanServiceExtensionTableName=WLANServiceExtensionTable
LanServiceExtensionTableRecordId=4
FIELD_COUNT=13
END_ADD

The socket is explicitly bound to the specific IP address of the network interface connection.

Explicit binding example

Client A creates a socket with explicit binding using the specified interface connection.

sock1 = RSocket.Open(srv,conn);

ESock creates the socket within the default connection and subconnection.

A socket can also be opened over a sub-connection using RSubConnection. When the socket is opened, a new Service Access Point (SAP) is created for the socket in ESock. The SAP is used to handle inbound and outbound data.

Parent topic: Socket Server Tutorials