Instead, intruduce StreamTcpDisableAppLayer to disable app layer
tracking and reassembly. StreamTcpAppLayerIsDisabled can be used
to check it.
Replace all uses of FlowSetSessionNoApplayerInspectionFlag and
the FLOW_NO_APPLAYER_INSPECTION.
Implement StreamTcpSetDisableRawReassemblyFlag() which stops raw
reassembly for _NEW_ segments in a stream direction.
It is used only by TLS/SSL now, to flag the streams as encrypted.
Existing segments will still be reassembled and inspected, while
new segments won't be. This allows for pattern based inspection
of the TLS handshake.
Like is the case with completely disabled 'raw' reassembly, the
logic is that the segments are flagged as completed for 'raw' right
away. So they are not considered in raw reassembly anymore.
As no new segments will be considered, the chunk limit check will
return true on the next call.
To be able to register counters from AppLayerGetCtxThread, the
ThreadVars pointer needs to be available in it and thus in it's
callers:
- AppLayerGetCtxThread
- DecodeThreadVarsAlloc
- StreamTcpReassembleInitThreadCtx
StreamMsgs would be stored in a per thread queue before being
attached to the tcp ssn. This is unnecessary, so this patch
removes this queue and puts the smsgs into the ssn directly.
Large patch as it affects a lot of tests.
Preparation for removing flow pointer from StreamMsg. Instead of
getting the ssn indirectly through StreamMsg->flow, we pass it
directly as all callers have it already.
This patch adds a memory counter for HTP memory usage. As
there is no thread variables available in application layer
the counter has been added to the TCP reassembly thread.
app-layer.[ch], app-layer-detect-proto.[ch] and app-layer-parser.[ch].
Things addressed in this commit:
- Brings out a proper separation between protocol detection phase and the
parser phase.
- The dns app layer now is registered such that we don't use "dnstcp" and
"dnsudp" in the rules. A user who previously wrote a rule like this -
"alert dnstcp....." or
"alert dnsudp....."
would now have to use,
alert dns (ipproto:tcp;) or
alert udp (app-layer-protocol:dns;) or
alert ip (ipproto:udp; app-layer-protocol:dns;)
The same rules extend to other another such protocol, dcerpc.
- The app layer parser api now takes in the ipproto while registering
callbacks.
- The app inspection/detection engine also takes an ipproto.
- All app layer parser functions now take direction as STREAM_TOSERVER or
STREAM_TOCLIENT, as opposed to 0 or 1, which was taken by some of the
functions.
- FlowInitialize() and FlowRecycle() now resets proto to 0. This is
needed by unittests, which would try to clean the flow, and that would
call the api, AppLayerParserCleanupParserState(), which would try to
clean the app state, but the app layer now needs an ipproto to figure
out which api to internally call to clean the state, and if the ipproto
is 0, it would return without trying to clean the state.
- A lot of unittests are now updated where if they are using a flow and
they need to use the app layer, we would set a flow ipproto.
- The "app-layer" section in the yaml conf has also been updated as well.
Add counter to the stream reassembly engine to count stream gaps. Stream gaps
are the result of missing packets (usually due to packet loss). This missing
data stops the reassembly for the app layer.
Added stream counters:
- tcp.reassembly_memuse -- current memory use by reassembly in bytes
- tcp.memuse -- current memory use by stream tracking in bytes
- tcp.reused_ssn -- ssn reused by new session with identical tuple
- tcp.no_flow -- TCP packets with no flow - indicating flow engine memory at its limits
The stream engine memory handling needed updating as it didn't scale. Changes:
- pools can now be initialized to size 0, meaning unlimited
- stream engine uses a memcap setting. Sessions, segments and aldata is part
of this, app layer state isn't.
- memory is accounted using a global int that is spinlocked.
- a counter for sessions that have not been picked up because of memcap was
added.
- all reassembly errors are converted to debug msgs.
- Implement "closing" state in flow.
- Add protocol specific timeouts.
- Lots of stream tracking updates, fixing a lot of out of window issues.
- Stream reassembly fixes.
- Implement a new IDS runmode with 4 stream and detect threads.
- Added a BUG_ON macro that aborts the engine if the expression is true.
- Better balance the flow queue handler for traffic that doesn't have flow (like icmp currently).
- Simplify application level protocol in the Tcp Session.
- Add some debugging memory counters.
Victor Julien
Eric Leblond
Anoop Saldanha
Gurvinder Singh
Anoop Saldanha
Pablo Rincon
William Metcalf
Jason Ish
Brian Rectanus