User Guide

9.6. How to produce protocol stats
Given that you have a tap interface for the protocol, you can use this to produce some interesting
statistics (well presumably interesting!) from protocol traces.
This can be done in a separate plugin, or in the same plugin that is doing the dissection. The latter
scheme is better, as the tap and stats module typically rely on sharing protocol specific data, which
might get out of step between two different plugins.
Here is a mechanism to produce statistics from the above TAP interface.
Example 9.22. Initialising a stats interface
/* register all http trees */
static void register_foo_stat_trees(void) {
stats_tree_register("foo","foo","Foo/Packet Types",
foo_stats_tree_packet, foo_stats_tree_init, NULL );
}
#ifndef ENABLE_STATIC
//G_MODULE_EXPORT const gchar version[] = "0.0";
G_MODULE_EXPORT void plugin_register_tap_listener(void)
{
register_foo_stat_trees();
}
#endif
Working from the bottom up, first the plugin interface entry point is defined, plu-
gin_register_tap_listener. This simply calls the initialisation function register_foo_stat_trees.
This in turn calls the stats_tree_register function, which takes three strings, and three functions.
1. This is the tap name that is registered.
2. An abbreviation of the stats name.
3. The name of the stats module. A '/' character can be used to make sub menus.
4. The function that will called to generate the stats.
5. A function that can be called to initialise the stats data.
6. A function that will be called to clean up the stats data.
In this case we only need the first two functions, as there is nothing specific to clean up.
Example 9.23. Initialising a stats session
static const guint8* st_str_packets = "Total Packets";
static const guint8* st_str_packet_types = "FOO Packet Types";
static int st_node_packets = -1;
static int st_node_packet_types = -1;
static void foo_stats_tree_init(stats_tree* st) {
st_node_packets = stats_tree_create_node(st, st_str_packets, 0, TRUE);
st_node_packet_types = stats_tree_create_pivot(st, st_str_packet_types, st_node_packets);
}
Packet dissection
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