Wireshark-dev: Re: [Wireshark-dev] Registering Dissector for Private SNAP PID
From: Christopher Merck <[email protected]>
Date: Wed, 3 Apr 2013 14:42:11 +0000
On 2013-03-05, Guy Harris wrote:
> On Mar 5, 2013, at 5:39 AM, Christopher Merck <[email protected]>
> wrote:
>>  I believe the correct way to proceed is to register a new dissector
> table along the lines of "llc.oui",
> I believe the correct way to proceed would be to add llc_add_oui() to
> the Lua API, so that Lua dissectors that need to handle a not-already-
> registered OUI can register that OUI, including a new dissector table
> for PIDs in that OUI, and then a dissector (no matter what language it's
> in) could register in that table.

I almost have this working. But what I don't understand is the fourth argument to llc_add_oui. That structure contains a list of PIDs to register and the table name. However, when I am registering the OUI I don't want to register any PIDs yet, and I have already specified the table_name as the second argument to llc_add_oui.

So, I'm trying to stuff some dummy data into hf_pid, but I get segfaults or assertion errors at runtime.

Any idea what I'm missing?



WSLUA_FUNCTION wslua_llc_add_oui(lua_State* LS) { /* registers a new OUI for LLC/SNAP purposes */
#define WSLUA_ARG_llc_add_oui_OUI 1             /* OUI to register */
#define WSLUA_ARG_llc_add_oui_TABLE_NAME 2      /* name of table to register, should be of the form: llc.<ouiname>_pid*/
#define WSLUA_ARG_llc_add_oui_TABLE_UI_NAME 3   /* name to display in GUI */
        lua_Number oui = luaL_checknumber(LS,WSLUA_ARG_llc_add_oui_OUI);
        const gchar* table_name = luaL_checkstring(LS,WSLUA_ARG_llc_add_oui_TABLE_NAME);
        const gchar* table_ui_name = luaL_checkstring(LS,WSLUA_ARG_llc_add_oui_TABLE_UI_NAME);

        const value_string oui_pid_vals[] = { { 0, NULL } };
        gint hf_llc_oui_pid = -1;
        hf_register_info hf_pid = {
                { "PID", NULL /*table_name*/,
                  FT_UINT16, BASE_HEX, VALS(oui_pid_vals),
                  0x0, NULL, HFILL }
        hf_pid.hfinfo.abbrev = table_name;

llc_add_oui(guint32 oui, const char *table_name, const char *table_ui_name,
    hf_register_info *hf_item)

      // TODO: What do to about the fourth argument?

        llc_add_oui(oui, table_name, table_ui_name, &hf_pid);

        return 0;

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