[sr-dev] SIP Congestion/Overload Control

Hi all, I am currently developing a module for offering overload control support as proposed in http://tools.ietf.org/html/draft-ietf-soc-overload-control-02 . As background: the idea behind draft-ietf-soc-overload-control-02 is, that the upstream node ads parameters to the own Via-header to signal the next downstream node its ability to understand overload-control signalling. In case of overload of the downstream node, this node downstream node extends the own Via-Header (sent in replies to the upstream node) with e.g., a droprate. Well, and the job of the oc-module will be to 1) add "oc" to the Via-headers in requests (ok) 2) parse the Via-Header of the replies for oc-droprates and durations (ok) 3) keep a list of overloaded downstream-hosts, the droprate and the duration of the droprate (failed - see below) 4) its own droprate and the duration communicated to other upstream neighbors (failed - see below) The module "oc" (currently) exports the following commands and params static cmd_export_t cmds[]={ {"oc_check_enabled", ... {"oc_check_downstream_overloaded", ... {"oc_setdroprate", oc_setdroprate, ... {0,0,0,0,0} }; static param_export_t params[]={ {"oc_enabled", PARAM_INT, &OC_ENABLED}, {0,0,0} }; and the rpc-methods static rpc_export_t rpc_methods[] = { {"oc.stats",...}, {"oc.set_oc"...}, {"oc.set_oc_duration",...}, {0, 0, 0, 0} }; Well, and now my problem: Manipulating the own Via-Header is (in my understanding) a very tricky part: in msg_translator.c the functions "build_req_buf_from_sip_req()" and "build_res_bug_from_sip_res()" are responsible for adding the own Via-Header and its parameters. So, I had to add a function call to functions inside my oc-module: oc_via_manipulation() and oc_builder(). And here is the problem: I cannot access the shared memory variables of the oc-module like oc_duration and oc_droprate when I call the oc_via_manipulation() and oc_builder()-functions from within "build_req_buf_from_sip_req()" and "build_res_bug_from_sip_res()". My conclusion was, that when calling functions of the oc-module from within the ser-"core", the shared-memory variables set by rpc_methods, cmds and params are not accessible. Honestly, I have now no idea how to continue and would be happy on every idea, br Michael -- Michael Hirschbichler, Mag. Dipl.-Ing. Institute of Telecommunications Vienna University of Technology A-1040 Wien, Favoritenstr. 9-11/388 Phone: +43 1 58801 38846