[lwip-users] Directly accessing tcp.local_port in a netconn

[Marco Jakobs]

Hi,

 

due to very limited resources I need to do a strange thing ;-)

 

I need to change the listener port of one single TCP listening connection "on the fly" in its idle state.

 

I've got this structure:

 

                // Superserver Connection Handles

                struct

                {

                               struct netconn                 *conn;                                 // Pointer auf die Netconn

                               unsigned char                                  conn_id;                             // ID der zugehörigen Connection, Ist auch Kenner ob die netconn belegt ist (wenn !=0)

                               unsigned char                                  conn_sub;                          // ID der zugehörigen Subconnection

                } ssrv_netconn [anz_supersrv_netconns];

 

The ssrv_netconn[2] is my active listening connection. Within this construct, the listening port has the path:

 

ssrv_netconn[2] -> conn -> pcb -> tcp -> local_port

 

Looks easy, but due to the complicated structure of the netconn in LwIp I have absolutely no clue how I can change the value of "local_port" :-(

 

So, let's say I want to set the "local_port" mentiones above to "1234". How should my C line look like? I've played around a while with combinations of dots and "->", but I can't get that without compiler errors.

 

Any ideas are highly appreciated.

 

VBR,

Marco