We already performed exactly these lookups in the generic code to
populate `flow->guessed_protocol_id_by_ip`: use it!
This code probably needs a deeper review, since it is basicaly a simple
matching on ip + port.
These flows are classifed as `LINE_CALL`; another option was
`RTP/LINE_CALL`. No sure about the best solution...
Extend LINE domains list.
Remove RTP dead code.
0 as size value disable the cache.
The diffs in unit tests are due to the fact that some lookups are
performed before the first insert: before this change these lookups
weren't counted because the cache was not yet initialized, now they are.
Basically:
* "classification by-ip" (i.e. `flow->guessed_protocol_id_by_ip` is
NEVER returned in the protocol stack (i.e.
`flow->detected_protocol_stack[]`);
* if the application is interested into such information, it can access
`ndpi_protocol->protocol_by_ip` itself.
There are mainly 4 points in the code that set the "classification
by-ip" in the protocol stack: the generic `ndpi_set_detected_protocol()`/
`ndpi_detection_giveup()` functions and the HTTP/STUN dissectors.
In the unit tests output, a print about `ndpi_protocol->protocol_by_ip`
has been added for each flow: the huge diff of this commit is mainly due
to that.
Strictly speaking, this change is NOT an API/ABI breakage, but there are
important differences in the classification results. For examples:
* TLS flows without the initial handshake (or without a matching
SNI/certificate) are simply classified as `TLS`;
* similar for HTTP or QUIC flows;
* DNS flows without a matching request domain are simply classified as
`DNS`; we don't have `DNS/Google` anymore just because the server is
8.8.8.8 (that was an outrageous behaviour...);
* flows previusoly classified only "by-ip" are now classified as
`NDPI_PROTOCOL_UNKNOWN`.
See #1425 for other examples of why adding the "classification by-ip" in
the protocol stack is a bad idea.
Please, note that IPV6 is not supported :( (long standing issue in nDPI) i.e.
`ndpi_protocol->protocol_by_ip` wil be always `NDPI_PROTOCOL_UNKNOWN` for
IPv6 flows.
Define `NDPI_CONFIDENCE_MATCH_BY_IP` has been removed.
Close#1687
Add detection over TCP and fix detection over IPv6.
Rename some variables since Stun dissector is no more "udp-centric".
Stun dissector should always classified the flow as `STUN` or
`STUN/Something`.
Don't touch `flow->guessed_host_protocol_id` field, which should be
always be related to "ip-classification" only.
Add (basic) internal stats to the main data structures used by the
library; they might be usefull to check how effective these structures
are.
Add an option to `ndpiReader` to dump them; enabled by default in the
unit tests.
This new option enables/disables dumping of "num dissectors calls"
values, too (see b4cb14ec).
As a general rule, the higher the confidence value, the higher the
"reliability/precision" of the classification.
In other words, this new field provides an hint about "how" the flow
classification has been obtained.
For example, the application may want to ignore classification "by-port"
(they are not real DPI classifications, after all) or give a second
glance at flows classified via LRU caches (because of false positives).
Setting only one value for the confidence field is a bit tricky: more
work is probably needed in the next future to tweak/fix/improve the logic.
Improve Microsoft, GMail, Likee, Whatsapp, DisneyPlus and Tiktok
detection.
Add Vimeo, Fuze, Alibaba and Firebase Crashlytics detection.
Try to differentiate between Messenger/Signal standard flows (i.e chat)
and their VOIP (video)calls (like we already do for Whatsapp and
Snapchat).
Add a partial list of some ADS/Tracking stuff.
Fix Cassandra, Radius and GTP false positives.
Fix DNS, Syslog and SIP false negatives.
Improve GTP (sub)classification: differentiate among GTP-U, GTP_C and
GTP_PRIME.
Fix 3 LGTM warnings.
