Get an interface label from an agent

[Guillermo Rigotti <grigotti@exa.unicen.edu.ar>]

ns developers:


I am implementing CBTv2 in ns. A CBT agent needs to know the local
interface (its label) through a message (CBT PDU) has arrived. I have
not
find an efficient way to do it without modify C code defining a compiled

variable, iif_, as follows:
message.cc, add   : int iif_;
                  modif.:
MessageAgent::MessageAgent():Agent(PT_MESSAGE), iif_(2)
                   add   : bind("iif_", &iif_);
            add(recv): iif_ =
((hdr_cmn*)pkt->access(off_cmn_))->iface();

ns-default.tcl, add : Agent/Message set iif_ -2

then, a CBT agent access the interface label:
  set input_interface_label [messager set iif_]

(messager is an Agent/Message object)

Do anyone knows a way to do it entirely in Tcl?
thanks,

  Guillermo Rigotti