Make stream engine use the streaming buffer API for it's data storage.
This means that the data is stored in a single reassembled sliding
buffer. The subleties of the reassembly, e.g. overlap handling, are
taken care of at segment insertion.
The TcpSegments now have a StreamingBufferSegment that contains an
offset and a length. Using this the segment data can be retrieved
per segment.
Redo segment insertion. The insertion code is moved to it's own file
and is simplified a lot.
A major difference with the previous implementation is that the segment
list now contains overlapping segments if the traffic is that way.
Previously there could be more and smaller segments in the memory list
than what was seen on the wire.
Due to the matching of in memory segments and on the wire segments,
the overlap with different data detection (potential mots attacks)
is much more accurate.
Raw and App reassembly progress is no longer tracked per segment using
flags, but there is now a progress tracker in the TcpStream for each.
When pruning we make sure we don't slide beyond in-use segments. When
both app-layer and raw inspection are beyond the start of the segment
list, the segments might not be freed even though the data in the
streaming buffer is already gone. This is caused by the 'in-use' status
that the segments can implicitly have. This patch accounts for that
when calculating the 'left_edge' of the streaming window.
Raw reassembly still sets up 'StreamMsg' objects for content
inspection. They are set up based on either the full StreamingBuffer,
or based on the StreamingBufferBlocks if there are gaps in the data.
Reworked 'stream needs work' logic. When a flow times out the flow
engine checks whether a TCP flow still needs work. The
StreamNeedsReassembly function is used to test if a stream still has
unreassembled segments or uninspected stream chunks.
This patch updates the function to consider the app and/or raw
progress. It also cleans the function up and adds more meaningful
debug messages. Finally it makes it non-inline.
Unittests have been overhauled, and partly moved into their own files.
Remove lots of dead code.
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
Victor Julien
Jason Ish
Ken Steele