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wireshark/epan/wslua/wslua_listener.c

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/*
* wslua_listener.c
*
* Wireshark's interface to the Lua Programming Language
*
* Implementation of tap Listeners
*
* (c) 2006, Luis E. Garcia Ontanon <luis@ontanon.org>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
/* WSLUA_MODULE Listener Post-Dissection Packet Analysis */
#include "wslua.h"
WSLUA_CLASS_DEFINE(Listener,FAIL_ON_NULL("Listener"));
/*
A `Listener` is called once for every packet that matches a certain filter or has a certain tap.
It can read the tree, the packet's <<lua_class_Tvb,`Tvb`>> buffer as well as the tapped data, but it cannot add elements to the tree.
*/
static int tap_packet_cb_error_handler(lua_State* L) {
const gchar* error = lua_tostring(L,1);
static gchar* last_error = NULL;
static int repeated = 0;
static int next = 2;
gchar* where = (lua_pinfo) ?
wmem_strdup_printf(NULL, "Lua: on packet %i Error during execution of Listener packet callback",lua_pinfo->num) :
wmem_strdup_printf(NULL, "Lua: Error during execution of Listener packet callback") ;
/* show the error the 1st, 3rd, 5th, 9th, 17th, 33th... time it appears to avoid window flooding */
/* XXX the last series of identical errors won't be shown (the user however gets at least one message) */
if (! last_error) {
report_failure("%s:\n%s",where,error);
last_error = g_strdup(error);
repeated = 0;
next = 2;
wmem_free(NULL, where);
return 0;
}
if (g_str_equal(last_error,error) ) {
repeated++;
if ( repeated == next ) {
report_failure("%s happened %i times:\n %s",where,repeated,error);
next *= 2;
}
} else {
report_failure("%s happened %i times:\n %s",where,repeated,last_error);
g_free(last_error);
last_error = g_strdup(error);
repeated = 0;
next = 2;
report_failure("%s:\n %s",where,error);
}
wmem_free(NULL, where);
return 0;
}
static tap_packet_status lua_tap_packet(void *tapdata, packet_info *pinfo, epan_dissect_t *edt, const void *data) {
Listener tap = (Listener)tapdata;
tap_packet_status retval = TAP_PACKET_DONT_REDRAW;
TreeItem lua_tree_tap;
if (tap->packet_ref == LUA_NOREF) return TAP_PACKET_DONT_REDRAW; /* XXX - report error and return TAP_PACKET_FAILED? */
lua_settop(tap->L,0);
lua_pushcfunction(tap->L,tap_packet_cb_error_handler);
lua_rawgeti(tap->L, LUA_REGISTRYINDEX, tap->packet_ref);
push_Pinfo(tap->L, pinfo);
push_Tvb(tap->L, edt->tvb);
if (tap->extractor) {
tap->extractor(tap->L,data);
} else {
lua_pushnil(tap->L);
}
lua_pinfo = pinfo;
lua_tvb = edt->tvb;
lua_tree_tap = create_TreeItem(edt->tree, NULL);
lua_tree = lua_tree_tap;
switch ( lua_pcall(tap->L,3,1,1) ) {
case 0:
/* XXX - treat 2 as TAP_PACKET_FAILED? */
retval = luaL_optinteger(tap->L,-1,1) == 0 ? TAP_PACKET_DONT_REDRAW : TAP_PACKET_REDRAW;
break;
case LUA_ERRRUN:
/* XXX - TAP_PACKET_FAILED? */
break;
case LUA_ERRMEM:
ws_warning("Memory alloc error while calling listener tap callback packet");
/* XXX - TAP_PACKET_FAILED? */
break;
case LUA_ERRERR:
ws_warning("Error while running the error handler function for listener tap callback");
break;
default:
ws_assert_not_reached();
break;
}
clear_outstanding_Pinfo();
clear_outstanding_Tvb();
lua_pinfo = NULL;
lua_tvb = NULL;
lua_tree = NULL;
g_free(lua_tree_tap);
return retval;
}
static int tap_reset_cb_error_handler(lua_State* L) {
const gchar* error = lua_tostring(L,1);
report_failure("Lua: Error during execution of Listener reset callback:\n %s",error);
return 0;
}
static void lua_tap_reset(void *tapdata) {
Listener tap = (Listener)tapdata;
if (tap->reset_ref == LUA_NOREF) return;
lua_pushcfunction(tap->L,tap_reset_cb_error_handler);
lua_rawgeti(tap->L, LUA_REGISTRYINDEX, tap->reset_ref);
switch ( lua_pcall(tap->L,0,0,lua_gettop(tap->L)-1) ) {
case 0:
break;
case LUA_ERRRUN:
ws_warning("Runtime error while calling a listener's init()");
break;
case LUA_ERRMEM:
ws_warning("Memory alloc error while calling a listener's init()");
break;
case LUA_ERRERR:
ws_warning("Error while running the error handler function for a listener's init()");
break;
default:
ws_assert_not_reached();
break;
}
}
static int tap_draw_cb_error_handler(lua_State* L) {
const gchar* error = lua_tostring(L,1);
report_failure("Lua: Error during execution of Listener draw callback:\n %s",error);
return 0;
}
static void lua_tap_draw(void *tapdata) {
Listener tap = (Listener)tapdata;
const gchar* error;
if (tap->draw_ref == LUA_NOREF) return;
lua_pushcfunction(tap->L,tap_draw_cb_error_handler);
lua_rawgeti(tap->L, LUA_REGISTRYINDEX, tap->draw_ref);
switch ( lua_pcall(tap->L,0,0,lua_gettop(tap->L)-1) ) {
case 0:
/* OK */
break;
case LUA_ERRRUN:
error = lua_tostring(tap->L,-1);
ws_warning("Runtime error while calling a listener's draw(): %s",error);
break;
case LUA_ERRMEM:
ws_warning("Memory alloc error while calling a listener's draw()");
break;
case LUA_ERRERR:
ws_warning("Error while running the error handler function for a listener's draw()");
break;
default:
ws_assert_not_reached();
break;
}
}
/* TODO: we should probably use a Lua table here */
static GPtrArray *listeners = NULL;
static void deregister_Listener (lua_State* L _U_, Listener tap) {
if (tap->all_fields) {
epan_set_always_visible(FALSE);
tap->all_fields = FALSE;
}
remove_tap_listener(tap);
g_free(tap->filter);
g_free(tap->name);
g_free(tap);
}
WSLUA_CONSTRUCTOR Listener_new(lua_State* L) {
/* Creates a new `Listener` tap object. */
#define WSLUA_OPTARG_Listener_new_TAP 1 /* The name of this tap. See <<lua_fn_Listener_list__,`Listener.list()`>> for a way to print valid listener names. */
#define WSLUA_OPTARG_Listener_new_FILTER 2 /*
A display filter to apply to the tap.
The `tap.packet` function will be called for each matching packet.
The default is `nil`, which matches every packet.
Example: "m2tp".
*/
#define WSLUA_OPTARG_Listener_new_ALLFIELDS 3 /*
Whether to generate all fields.
The default is `false`.
Note: This impacts performance. */
const gchar* tap_type = luaL_optstring(L,WSLUA_OPTARG_Listener_new_TAP,"frame");
const gchar* filter = luaL_optstring(L,WSLUA_OPTARG_Listener_new_FILTER,NULL);
const gboolean all_fields = wslua_optbool(L, WSLUA_OPTARG_Listener_new_ALLFIELDS, FALSE);
Listener tap;
GString* error;
tap = (Listener)g_malloc(sizeof(struct _wslua_tap));
tap->name = g_strdup(tap_type);
tap->filter = g_strdup(filter);
tap->extractor = wslua_get_tap_extractor(tap_type);
tap->L = L;
tap->packet_ref = LUA_NOREF;
tap->draw_ref = LUA_NOREF;
tap->reset_ref = LUA_NOREF;
tap->all_fields = all_fields;
/*
* XXX - do all Lua taps require the protocol tree? If not, it might
* be useful to have a way to indicate whether any do.
*
* XXX - do any Lua taps require the columns? If so, we either need
* to request them for this tap, or do so if any Lua taps require them.
*/
error = register_tap_listener(tap_type, tap, tap->filter, TL_REQUIRES_PROTO_TREE, lua_tap_reset, lua_tap_packet, lua_tap_draw, NULL);
if (error) {
g_free(tap->filter);
g_free(tap->name);
g_free(tap);
/* WSLUA_ERROR(new_tap,"tap registration error"); */
lua_pushfstring(L,"Error while registering tap:\n%s",error->str);
g_string_free(error,TRUE);
return luaL_error(L,lua_tostring(L,-1));
}
if (all_fields) {
epan_set_always_visible(TRUE);
}
g_ptr_array_add(listeners, tap);
pushListener(L,tap);
WSLUA_RETURN(1); /* The newly created Listener listener object */
}
/* Allow dissector key names to be sorted alphabetically */
static gint
compare_dissector_key_name(gconstpointer dissector_a, gconstpointer dissector_b)
{
return strcmp((const char*)dissector_a, (const char*)dissector_b);
}
WSLUA_CONSTRUCTOR Listener_list (lua_State *L) { /*
Gets a Lua array table of all registered `Listener` tap names.
Note: This is an expensive operation, and should only be used for troubleshooting.
@since 1.11.3
===== Example
[source,lua]
----
-- Print a list of tap listeners to stdout.
for _,tap_name in pairs(Listener.list()) do
print(tap_name)
end
----
*/
GList* list = get_tap_names();
GList* elist = NULL;
int i = 1;
if (!list) return luaL_error(L,"Cannot retrieve tap name list");
list = g_list_sort(list, (GCompareFunc)compare_dissector_key_name);
elist = g_list_first(list);
lua_newtable(L);
for (i=1; elist; i++, elist = g_list_next(elist)) {
lua_pushstring(L,(const char *) elist->data);
lua_rawseti(L,-2,i);
}
g_list_free(list);
WSLUA_RETURN(1); /* The array table of registered tap names */
}
WSLUA_METHOD Listener_remove(lua_State* L) {
/* Removes a tap `Listener`. */
Listener tap = checkListener(L,1);
if (listeners && g_ptr_array_remove(listeners, tap)) {
deregister_Listener(L, tap);
}
return 0;
}
WSLUA_METAMETHOD Listener__tostring(lua_State* L) {
/* Generates a string of debug info for the tap `Listener`. */
Listener tap = checkListener(L,1);
lua_pushfstring(L,"Listener(%s) filter: %s",tap->name, tap->filter ? tap->filter : "NONE");
return 1;
}
/* WSLUA_ATTRIBUTE Listener_packet WO A function that will be called once every packet matches the
`Listener` listener filter.
When later called by Wireshark, the `packet` function will be given:
1. A `Pinfo` object
2. A `Tvb` object
3. A `tapinfo` table
[source,lua]
----
function tap.packet(pinfo,tvb,tapinfo) ... end
----
[NOTE]
====
`tapinfo` is a table of info based on the `Listener`'s type, or nil.
====
*/
WSLUA_ATTRIBUTE_FUNC_SETTER(Listener,packet);
/* WSLUA_ATTRIBUTE Listener_draw WO A function that will be called once every few seconds to redraw the GUI objects;
in Tshark this funtion is called only at the very end of the capture file.
When later called by Wireshark, the `draw` function will not be given any arguments.
[source,lua]
----
function tap.draw() ... end
----
*/
WSLUA_ATTRIBUTE_FUNC_SETTER(Listener,draw);
/* WSLUA_ATTRIBUTE Listener_reset WO A function that will be called at the end of the capture run.
When later called by Wireshark, the `reset` function will not be given any arguments.
[source,lua]
----
function tap.reset() ... end
----
*/
WSLUA_ATTRIBUTE_FUNC_SETTER(Listener,reset);
static int Listener__gc(lua_State* L _U_) {
/* do NOT free Listener here, only in deregister_Listener */
return 0;
}
/* This table is ultimately registered as a sub-table of the class' metatable,
* and if __index/__newindex is invoked then it calls the appropriate function
* from this table for getting/setting the members.
*/
WSLUA_ATTRIBUTES Listener_attributes[] = {
WSLUA_ATTRIBUTE_WOREG(Listener,packet),
WSLUA_ATTRIBUTE_WOREG(Listener,draw),
WSLUA_ATTRIBUTE_WOREG(Listener,reset),
{ NULL, NULL, NULL }
};
WSLUA_METHODS Listener_methods[] = {
WSLUA_CLASS_FNREG(Listener,new),
WSLUA_CLASS_FNREG(Listener,remove),
WSLUA_CLASS_FNREG(Listener,list),
{ NULL, NULL }
};
WSLUA_META Listener_meta[] = {
WSLUA_CLASS_MTREG(Listener,tostring),
{ NULL, NULL }
};
int Listener_register(lua_State* L) {
wslua_set_tap_enums(L);
listeners = g_ptr_array_new();
WSLUA_REGISTER_CLASS_WITH_ATTRS(Listener);
return 0;
}
static void deregister_tap_listener (gpointer data, gpointer userdata) {
lua_State *L = (lua_State *) userdata;
Listener tap = (Listener) data;
deregister_Listener(L, tap);
}
int wslua_deregister_listeners(lua_State* L) {
g_ptr_array_foreach(listeners, deregister_tap_listener, L);
g_ptr_array_free(listeners, TRUE);
listeners = NULL;
return 0;
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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