The idea is to remove the limitation of only two protocols ("master" and
"app") in the flow classifcation.
This is quite handy expecially for STUN flows and, in general, for any
flows where there is some kind of transitionf from a cleartext protocol
to TLS: HTTP_PROXY -> TLS/Youtube; SMTP -> SMTPS (via STARTTLS msg).
In the vast majority of the cases, the protocol stack is simply
Master/Application.
Examples of real stacks (from the unit tests) different from the standard
"master/app":
* "STUN.WhatsAppCall.SRTP": a WA call
* "STUN.DTLS.GoogleCall": a Meet call
* "Telegram.STUN.DTLS.TelegramVoip": a Telegram call
* "SMTP.SMTPS.Google": a SMTP connection to Google server started in
cleartext and updated to TLS
* "HTTP.Google.ntop": a HTTP connection to a Google domain (match via
"Host" header) and to a ntop server (match via "Server" header)
The logic to create the stack is still a bit coarse: we have a decade of
code try to push everything in only ywo protocols... Therefore, the
content of the stack is still **highly experimental** and might change
in the next future; do you have any suggestions?
It is quite likely that the legacy fields "master_protocol" and
"app_protocol" will be there for a long time.
Add some helper to use the stack:
```
ndpi_stack_get_upper_proto();
ndpi_stack_get_lower_proto();
bool ndpi_stack_contains(struct ndpi_proto_stack *s, u_int16_t proto_id);
bool ndpi_stack_is_tls_like(struct ndpi_proto_stack *s);
bool ndpi_stack_is_http_like(struct ndpi_proto_stack *s);
```
Be sure new stack logic is compatible with legacy code:
```
assert(ndpi_stack_get_upper_proto(&flow->detected_protocol.protocol_stack) ==
ndpi_get_upper_proto(flow->detected_protocol));
assert(ndpi_stack_get_lower_proto(&flow->detected_protocol.protocol_stack) ==
ndpi_get_lower_proto(flow->detected_protocol));
```
ProtonVPN script have been not working in the last week.
```
Error "Invalid access token"
```
ProtonVPN is doing a major upgrade in its infrastructure:
```
In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary.
Apr 09, 2025 - 11:30 CEST
Scheduled - In the following period from the 9th of April up to the 30th of April, various Proton VPN dedicated servers will be in temporary maintenance mode, for a short duration period, in order to allow us to perform a major infrastructure upgrade, paving the way for overall increased performance and efficiency of our Proton VPN infrastructure.
We apologize for the occasional inconvenience.
Apr 9, 2025 11:30 - Apr 30, 2025 23:30 CEST
```
Let's wait if it works again in the future...
This function is always called once for every flow, as last code
processing the flow itself.
As a first usage example, check here if the flow is unidirectional
(instead of checking it at every packets)
The `suffix_id` is simply an incremental index (see
`ndpi_load_domain_suffixes`), so its value might changes every time we
update the public suffix list.
This cache was added in b6b4967aa, when there was no real Zoom support.
With 63f349319, a proper identification of multimedia stream has been
added, making this cache quite useless: any improvements on Zoom
classification should be properly done in Zoom dissector.
Tested for some months with a few 10Gbits links of residential traffic: the
cache pretty much never returned a valid hit.
