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.
Remove some unused fields and re-organize other ones.
In particular:
* Update the parameters of `ndpi_ssl_version2str()` function
* Zattoo, Thunder: these timestamps aren't really used.
* Ftp/mail: these protocols are dissected only over TCP.
* Attention must be paid to TLS.Bittorrent flows to avoid invalid
read/write to `flow->protos.bittorrent.hash` field.
This is the last(?) commit of a long series (see 22241a1d, 227e586e,
730c2360, a8ffcd8b) aiming to reduce library memory consumption.
Before, at nDPI 4.0 (more precisly, at a6b10cf7, because memory stats
were wrong until that commit):
```
nDPI Memory statistics:
nDPI Memory (once): 221.15 KB
Flow Memory (per flow): 2.94 KB
```
Now:
```
nDPI Memory statistics:
nDPI Memory (once): 231.71 KB
Flow Memory (per flow): 1008 B <---------
```
i.e. memory usage per flow has been reduced by 66%, dropping below the
psychological threshold of 1 KB.
To further reduce this value, we probably need to look into #1279:
let's fight this battle another day.
Looking at `struct ndpi_flow_struct` the two bigger fields are
`host_server_name[240]` (mainly for HTTP hostnames and DNS domains) and
`protos.tls_quic.client_requested_server_name[256]`
(for TLS/QUIC SNIs).
This commit aims to reduce `struct ndpi_flow_struct` size, according to
two simple observations:
1) maximum one of these two fields is used for each flow. So it seems safe
to merge them;
2) even if hostnames/SNIs might be very long, in practice they are rarely
longer than a fews tens of bytes. So, using a (single) large buffer is a
waste of memory for all kinds of flows. If we need to truncate the name,
we keep the *last* characters, easing domain matching.
Analyzing some real traffic, it seems safe to assume that the vast
majority of hostnames/SNIs is shorter than 80 bytes.
Hostnames/SNIs are always converted to lowercase.
Attention was given so as to be sure that unit-tests outputs are not
affected by this change.
Because of a bug, TLS/QUIC SNI were always truncated to 64 bytes (the
*first* 64 ones): as a consequence, there were some "Suspicious DGA
domain name" and "TLS Certificate Mismatch" false positives.
We can write to `flow->protos` only after a proper classification.
This issue has been found in Kerberos, DHCP, HTTP, STUN, IMO, FTP,
SMTP, IMAP and POP code.
There are two kinds of fixes:
* write to `flow->protos` only if a final protocol has been detected
* move protocol state out of `flow->protos`
The hard part is to find, for each protocol, the right tradeoff between
memory usage and code complexity.
Handle Kerberos like DNS: if we find a request, we set the protocol
and an extra callback to further parsing the reply.
For all the other protocols, move the state out of `flow->protos`. This
is an issue only for the FTP/MAIL stuff.
Add DHCP Class Identification value to the output of ndpiReader and to
the Jason serialization.
Extend code coverage of fuzz tests.
Close#1343Close#1342
`ndpiReader` is only an example, aiming to show nDPI capabilities
and integration, without any claim about performances.
Nonetheless its memory usage per flow is *huge*, limiting the kinds
of traces that we can test on a "normal" hardware (example: scan
attacks).
The key reason of that behaviour is that we preallocate all the memory
needed for *all* the available features.
Try to reduce memory usage simply allocating some structures only
when they are really needed. Most significant example: JOY algorithms.
This way we should use a lot less memory in the two most common
user-cases:
* `ndpiReader` invoked without any particular flag (i.e `ndpiReader -i
$FILENAME_OR_IFACE`)
* internal unit tests
Before (on x86_64):
```
struct ndpi_flow_info {
[...]
/* size: 7320, cachelines: 115, members: 72 */
```
After:
```
struct ndpi_flow_info {
[...]
/* size: 2128, cachelines: 34, members: 75 */
```
* fixed several memory errors (heap-overflow, unitialized memory, etc)
* ability to build fuzz_process_packet with a main()
allowing to replay crash data generated with fuzz_process_packet
by LLVMs libfuzzer
* temporarily disable fuzzing if `tests/do.sh`
executed with env FUZZY_TESTING_ENABLED=1
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
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.
Fix all the warnings.
Getting rid of "-Wno-unused-parameter" is quite complex because some
parameters usage depends on compilation variable (i.e.
`--enable-debug-messages`).
The "-Werror" flag has been added only in Travis builds to avoid
breaking the builds to users using uncommon/untested
OS/compiler/enviroment.
Tested on:
* x86_64; Ubuntu 20.04; gcc 7,8,9,10,11; clang 7,8,9,10,11,12
* x86_64; CentOS 7.7; gcc 4.8.5 (with "--disable-gcrypt" flag)
* Raspberry 4; Debian 10.10; gcc 8.3.0
* Added ARM build and unit test run for SonarCloud-CI.
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
* Fixed Mingw64 build.
* adapted to SonarCloud-CI workflow
* removed broken and incomplete Windows example (tested on VS2017/VS2019)
* removed unnecessary include (e.g. pthread.h for the library which does not make use of it)
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
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.
* Add support for Snapchat voip calls
Snapchat multiplexes some of its audio/video real time traffic with QUIC
sessions. The peculiarity of these sessions is that they are Q046 and
don't have any SNI.
* Fix tests with libgcrypt disabled
* Fixed memory leaks caused by conditional free'ing for some TLS connections.
* Members of tls_quic struct should also free'd if the detected master protocol is IMAPS / POPS / SMTPS / etc.
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
* Prevent reader_util.c from exit()'ing if maximum flow count reached.
This confuses the fuzzer.
* Improved fuzz/Makefile.am to use LDADD for ../example/libndpiReader.a instead of LDFLAGS.
That way, fuzz_ndpi_reader re-links to ../example/libndpiReader.a if something changed there.
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
