Currently out-of-order segments will result in cutting a stream into
two pieces while the out-of-order segment itself is ignored. For
example, a stream of segments "ABDCE" is interpreted as "AB", "DE" with
"C" ignored. This behavior breaks TLS decryption or prevent application
layer PDUs (such as HTTP requests/responses) from being reconstructed.
To fix this, buffer segments when a gap is detected.
The proposed approach extends the "multi-segment PDU" (MSP) mechanism
which is normally used for linking multiple, sequential TCP segments
into a single PDU. When a gap is detected between segments, it is
assumed that the segments within this gap are out-of-order and will be
received (or retransmitted) later.
The current implementation has a limitation though, if multiple gaps
exist, then the subdissector will only be called when all gaps are
filled (the subdissector will receive segments later than necessary).
For example with "ACEBD", "ABC" can already be processed after "B" is
received (with "E" still buffered), but due to how MSP are extended, it
must receive "D" too before it reassembles "ABCDE". In practice this
could mean that the request/response times between HTTP requests and
responses are slightly off, but at least the stream is correct now.
(These limitations are documented in the User's Guide.)
As the feature fails at least the 802.11 decryption test where packets
are missing (instead of OoO), hide this feature behind a preference.
Tested with captures containing out-of-order TCP segments from the
linked bug reports, comparing the effect of toggling the preference on
the summary output of tshark, the verbose output (-V) and the two-pass
output (-2 or -2V). Captures marked with "ok" just needed "simple"
out-of-order handling. Captures marked with "ok2" additionally required
the reassembly API change to set the correct reassembled length.
This change does "regress" on bug 10289 though when the preference is
enabled as retransmitted single-segment PDUs are now passed to
subdissectors. I added a TODO comment for this unrelated cosmetic issue.
Bug: 3389 # capture 2907 (HTTP) ok
Bug: 4727 # capture 4590 (HTTP) ok
Bug: 9461 # capture 12130 (TLS/HTTP/RPC-over-HTTP +key 12131) ok
Bug: 12006 # capture 14236 (HTTP) ok2; capture 15261 (HTTP) ok
Bug: 13517 # capture 15370 (HTTP) ok; capture 16059 (MQ) ok
Bug: 13754 # capture 15593 (MySQL) ok2
Bug: 14649 # capture 16305 (WebSocket) ok
Change-Id: If3938c5c1c96db8f7f50e39ea779f623ce657d56
Reviewed-on: https://code.wireshark.org/review/27943
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
Add the fileformats and I/O suites. Move some more common code to
subprocesstest.py and add a diffOutput method.
Change-Id: I2ec34e46539022bdce78520645fdca6dfc1a8c1a
Reviewed-on: https://code.wireshark.org/review/27183
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Create Python versions of our various test shell scripts. Add CMake
tests for each suite. Tests can now be run directly via test.py, via the
"test" target, or via ctest, e.g.
ctest --verbose --jobs 3
Add a testing chapter to the Developer's Guide.
Add a way to disable ctest in dpkg-buildpackage.
Suites completed:
- capture
- clopts
- decryption
- dissection
Remaining suites:
- fileformats
- io
- mergecap
- nameres
- text2pcap
- unittests
- wslua
Change-Id: I8936e05edefc76a86b6a7a5da302e7461bbdda0f
Reviewed-on: https://code.wireshark.org/review/27134
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Peter Wu