A given protocol's packet format may depend, for example, on which
lower-level protocol is transporting the protocol in question. For
example, protocols that run atop both byte-stream protocols such as TCP
and TLS, and packet-oriented protocols such as UDP or DTLS, might begin
the packet with a length when running atop a byte-stream protocol, to
indicate where this packet ends and the next packet begins in the byte
stream, but not do so when running atop a packet-oriented protocol.
Dissectors can handle this in various ways:
For example, the dissector could attempt to determine the protocol over
which the packet was transported.
Unfortunately, many of those mechanisms do so by fetching data from the
packet_info structure, and many items in that structure act as global
variables, so that, for example, if there are two two PDUs for protocol
A inside a TCP segment, and the first protocol for PDU A contains a PDU
for protocol B, and protocol B's dissector, or a dissector it calls,
modifies the information in the packet_info structure so that it no
longer indicates that the parent protocol is TCP, the second PDU for
protocol A might not be correctly dissected.
Another such mechanism is to query the previous element in the layers
structure of the packet_info structure, which is a list of protocol IDs.
Unfortunately, that is not a list of earlier protocols in the protocol
stack, it's a list of earlier protocols in the dissection, which means
that, in the above example, when the second PDU for protocol A is
dissected, the list is {...,TCP,A,B,...,A}, which means that the
previous element in the list is not TCP, so, again, the second PDU for
protocol A will not be correctly dissected.
An alternative is to have multiple dissectors for the same protocol,
with the part of the protocol that's independent of the protocol
transporting the PDU being dissected by common code. Protocol B might
have an "over a byte-stream transport" dissector and an "over a packet
transport" dissector, with the first dissector being registered for use
over TCP and TLS and the other dissector being registered for use over
packet protocols. This mechanism, unlike the other mechanisms, is not
dependent on information in the packet_info structure that might be
affected by dissectors other than the one for the protocol that
transports protocol B.
Furthermore, in a LINKTYPE_WIRESHARK_UPPER_PDU pcap or pcapng packet for
protocol B, there might not be any information to indicate the protocol
that transports protocol B, so there would have to be separate
dissectors for protocol B, with separate names, so that a tag giving the
protocol name would differ for B-over-byte-stream and B-over-packets.
So:
We rename EXP_PDU_TAG_PROTO_NAME and EXP_PDU_TAG_HEUR_PROTO_NAME to
EXP_PDU_TAG_DISSECTOR_NAME and EXP_PDU_TAG_HEUR_DISSECTOR_NAME, to
emphasize that they are *not* protocol names, they are dissector names
(which has always been the case - if there's a protocol with that name,
but no dissector with that name, Wireshark will not be able to handle
the packet, as it will try to look up a dissector given that name and
fail).
We fix that exported PDU dissector to refer to those tags as dissector
names, not protocol names.
We update documentation to refer to them as DISSECTOR_NAME tags, not
PROTO_NAME tags. (If there is any documentation for this outside the
Wireshark source, it should be updated as well.)
We add comments for calls to dissector_handle_get_dissector_name() where
the dissector name is shown to the user, to indicate that it might be
that the protocol name should be used.
We update the TLS and DTLS dissectors to show the encapsulated protocol
as the string returned by dissector_handle_get_long_name(); as the
default is "Application Data", it appeaers that a descriptive name,
rather than a short API name, should be used. (We continue to use the
dissector name in debugging messages, to indicate which dissector was
called.)
These display bases work to replace unprintable characters so the
name is a misnomer. In addition they are the same option and this
display behaviour is not something that is configurable.
This does not affect encodings because all our internal text strings
need to be valid UTF-8 and the source encoding is specified using
ENC_*.
Remove the assertion for valid UTF-8 in proto.c because
tvb_get_*_string() must return a valid UTF-8 string, always, and we
don't need to assert that, it is expensive.
Since the gssapi handler can cope fine with ntlm blobs, remove the
heuristic in ntlmssp and call the gssapi dissector directly. In turn
we get kerberos support, including decpryption with keytab etc.
When there are more packets on the stream after credssp, like tpkt-rpd
data, the credssp heuristics fails when invoked by tls and then even the
packets for which the credssp heuristics succeeded do not get dissected
as credssp but as tpkt-continuation data.
To work around that, call the credssp heuristic dissector directly from
the rdp dissector before trying fastpath.
Leave the credssp heursitics in TLS for other protocols such as HTTP
where it may work.
Rename the "ssl" protocol to "tls" and add an "ssl" alias. Prefer "TLS"
over "SSL" in user interface text and in the documentation.
Fix the test_tls_master_secret test while we're here.
Bug: 14922
Change-Id: Iab6ba2c7c4c0f8f6dd0f6d5d90fac5e9486612f8
Reviewed-on: https://code.wireshark.org/review/29649
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Gerald Combs <gerald@wireshark.org>
It has been replaced by cmake.
Change-Id: I83a5eddb8645dbbf6bca9f026066d2e995d8e87a
Reviewed-on: https://code.wireshark.org/review/26969
Petri-Dish: Dario Lombardo <lomato@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
Now that nmake build system has been removed they are not needed anymore.
Change-Id: I88075f955bb4349185859c1af4be22e53de5850f
Reviewed-on: https://code.wireshark.org/review/16050
Petri-Dish: João Valverde <j@v6e.pt>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: João Valverde <j@v6e.pt>
Rather than have a bitmask for each desired field, have a dissector
provide a list of structures that represent data that goes into
the PDU.
Change-Id: I125190cbaee489ebffb7d9f5d8bc6f3be2d06353
Reviewed-on: https://code.wireshark.org/review/16122
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
This will make it easier to determine protocol dependencies.
Some LLC OUI dissector tables didn't have an associated protocol, so they were left without one (-1 used)
Change-Id: I6339f16476510ef3f393d6fb5d8946419bfb4b7d
Reviewed-on: https://code.wireshark.org/review/14446
Reviewed-by: Michael Mann <mmann78@netscape.net>
Add missing newline or remove extra newlines at the end of the file.
Trim trailing whitespace.
Change-Id: I73b7a4e20969bc13f72bf97e981fd5de89d8bb17
Reviewed-on: https://code.wireshark.org/review/14400
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: João Valverde <j@v6e.pt>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Guy Harris