zeek/scripts/base/protocols/dnp3/main.zeek
Jon Siwek 31f60853c9 GH-646: add new "successful_connection_remove" event
And switch Zeek's base scripts over to using it in place of
"connection_state_remove".  The difference between the two is
that "connection_state_remove" is raised for all events while
"successful_connection_remove" excludes TCP connections that were never
established (just SYN packets).  There can be performance benefits
to this change for some use-cases.

There's also a new event called ``connection_successful`` and a new
``connection`` record field named "successful" to help indicate this new
property of connections.
2019-11-11 19:52:59 -08:00

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##! A very basic DNP3 analysis script that just logs requests and replies.
module DNP3;
@load ./consts
export {
redef enum Log::ID += { LOG };
type Info: record {
## Time of the request.
ts: time &log;
## Unique identifier for the connection.
uid: string &log;
## Identifier for the connection.
id: conn_id &log;
## The name of the function message in the request.
fc_request: string &log &optional;
## The name of the function message in the reply.
fc_reply: string &log &optional;
## The response's "internal indication number".
iin: count &log &optional;
};
## Event that can be handled to access the DNP3 record as it is sent on
## to the logging framework.
global log_dnp3: event(rec: Info);
}
redef record connection += {
dnp3: Info &optional;
};
const ports = { 20000/tcp , 20000/udp };
redef likely_server_ports += { ports };
event zeek_init() &priority=5
{
Log::create_stream(DNP3::LOG, [$columns=Info, $ev=log_dnp3, $path="dnp3"]);
Analyzer::register_for_ports(Analyzer::ANALYZER_DNP3_TCP, ports);
}
event dnp3_application_request_header(c: connection, is_orig: bool, application_control: count, fc: count)
{
if ( ! c?$dnp3 )
c$dnp3 = [$ts=network_time(), $uid=c$uid, $id=c$id];
c$dnp3$ts = network_time();
c$dnp3$fc_request = function_codes[fc];
}
event dnp3_application_response_header(c: connection, is_orig: bool, application_control: count, fc: count, iin: count)
{
if ( ! c?$dnp3 )
c$dnp3 = [$ts=network_time(), $uid=c$uid, $id=c$id];
c$dnp3$ts = network_time();
c$dnp3$fc_reply = function_codes[fc];
c$dnp3$iin = iin;
Log::write(LOG, c$dnp3);
delete c$dnp3;
}
event successful_connection_remove(c: connection) &priority=-5
{
if ( ! c?$dnp3 )
return;
Log::write(LOG, c$dnp3);
delete c$dnp3;
}