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.
Tell "Advertised" ALPN list from "Negotiated" ALPN; the former is
extracted from the CH, the latter from the SH.
Add some entries to the known ALPN list.
Fix printing of "TLS Supported Versions" field.
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.
The host automa is used for two tasks:
* protocol sub-classification (obviously);
* DGA evaluation: the idea is that if a domain is present in this
automa, it can't be a DGA, regardless of its format/name.
In most dissectors both checks are executed, i.e. the code is something
like:
```
ndpi_match_host_subprotocol(..., flow->host_server_name, ...);
ndpi_check_dga_name(..., flow->host_server_name,...);
```
In that common case, we can perform only one automa lookup: if we check the
sub-classification before the DGA, we can avoid the second lookup in
the DGA function itself.
If we have seen Application Data blocks in both directions, it means we
are after the handshake. At that point, extra dissection is useless.
Useful feature with TLS mid-sessions, i.e. sessions without initial
packets.
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).
Since e6b332aa, we have proper support for detecting client/server
direction. So Tinc dissector is now able to properly initialize the
cache entry only when needed and not anymore at the SYN time; initializing
that entry for **every** SYN packets was a complete waste of resources.
Since 4896dabb, the various `struct ndpi_call_function_struct`
structures are not more separate objects and therefore comparing them
using only their pointers is bogus: this bug was triggered by this
change because `ndpi_str->callback_buffer_size_tcp_no_payload` is now 0.
* #1532 did fx TLS appdata detection only partially
* use flow->l4.tcp.tls.message.buffer_used instead of packet->payload
Signed-off-by: lns <matzeton@googlemail.com>
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.
Decoding of ipv6 traffic with extension headers was completely broken,
since the beginning of the L4 header was always set to a wrong value.
Handle the ipv6 fragments in the same way as the ipv4 ones: keep the first
one and drop the others.
The goal is to have a (roughly) idea about how many packets nDPI needs
to properly classify a flow.
Log this information (and guessed flows number too) during unit tests,
to keep track of improvements/regressions across commits.
