From Vern in GH-846: This is a conscious decision in the TCP analysis to
consider a connection's "duration" to run up through the end of its
productive (= data can be delivered) lifetime, not extending beyond that. So
once it's closed, packets seen subsequently (until the state-holding for the
connection times out) get processed in terms of updating the associated
history, but not the duration. This can include (unnecessarily) retransmitted
data packets, like in one of the examples above. An advantage of this definition
of "duration" is it allows more accurate computation of connection data rates.
...the only known cases where the `-` for `connection$service` was
handled is to skip/ignore these analyzers.
Slight suspicion that join_string_set() should maybe become a bif
now determine_service() runs once for each connection.
Closes#2388
This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
The RSTOS0 `conn_state` label is documented as "Originator sent a SYN
followed by a RST, never saw SYN-ACK from responder", but was previously
applied to cases where no originator SYN exists, like a single RST-only
packet.
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.
* All "Broxygen" usages have been replaced in
code, documentation, filenames, etc.
* Sphinx roles/directives like ":bro:see" are now ":zeek:see"
* The "--broxygen" command-line option is now "--zeexygen"
* origin/topic/vern/content-gap-history:
Refined state machine update placement to (1) properly deal with gaps capped by clean FIN handshakes, and (1) fix failure to detect split routing.
added 'g' $history character for content gaps
