This usage devalues a mechanism for warning users that deserves more
attention than this minor suggestion.
The warning is inconvenient for intermediate and advanced users.
This change implements a unary minus operator.
Filter: tcp.window_size_scalefactor == -tcp.dstport
Instructions:
00000 READ_TREE tcp.window_size_scalefactor -> reg#0
00001 IF_FALSE_GOTO 6
00002 READ_TREE tcp.dstport -> reg#1
00003 IF_FALSE_GOTO 6
00004 MK_MINUS -reg#1 -> reg#2
00005 ANY_EQ reg#0 == reg#2
00006 RETURN
It is supported for integer types, floats and relative time values.
The unsigned integer types are promoted to a 32 bit signed integer.
Unary plus is implemented as a no-op. The plus sign is simply ignored.
Constant arithmetic expressions are computed during compilation.
Overflow with constants is a compile time error. Overflow with
variables is a run time error and silently ignored. Only a debug
message will be printed to the console.
Related to #15504.
Add support for masking of bits. Before the bitwise operator
could only test bits, it did not support clearing bits.
This allows testing if any combination of bits are set/unset
more naturally with a single test. Previously this was only
possible by combining several bitwise predicates.
Bitwise is implemented as a test node, even though it is not.
Maybe the test node should be renamed to something else.
Fixes#17246.
Comparisons require a field-like value on one of the sides,
or both. Change this to require on the LHS or both. There is
realy no reason that I can see to allow the relation to commute,
and it allows removing a lot of unnecessary code and extra tests.
For unparsed values on the RHS of a comparison try
to parse them first as a literal and only then as
a protocol. This is more complicated in code but
should be a use case a lot more common and useful in
practice.
It removes some annoying special cases and applies this
rule consistently to any expression. Consistency is
important otherwise the special cases and exceptions
make the language confusing and difficult to learn.
For values on the LHS the rule remains to first try a
protocol value, then a literal.
Related with issue #17731.
A literal value is a value that cannot be interpreted as a
registered protocol. An unparsed value can be a literal or
an identifier (protocol/field) according to context and the
current disambiguation rules.
Strictly literal here is to be understood to mean "numeric
literal, including numeric arrays, but not strings or character
constants".
The syntax for protocols and some literals like numbers
and bytes/addresses can be ambiguous. Some protocols can
be parsed as a literal, for example the protocol "fc"
(Fibre Channel) can be parsed as 0xFC.
If a numeric protocol is registered that will also take
precedence over any literal, according to the current
rules, thereby breaking numerical comparisons to that
number. The same for an hypothetical protocol named "true",
etc.
To allow the user to disambiguate this meaning introduce
new syntax.
Any value prefixed with ':' or enclosed in <,> will be treated
as a literal value only. The value :fc or <fc> will always
mean 0xFC, under any context. Never a protocol whose filter
name is "fc".
Likewise any value prefixed with a dot will always be parsed
as an identifier (protocol or protocol field) in the language.
Never any literal value parsed from the token "fc".
This allows the user to be explicit about the meaning,
and between the two explicit methods plus the ambiguous one
it doesn't completely break any one meaning.
The difference can be seen in the following two programs:
Filter: frame == fc
Constants:
Instructions:
00000 READ_TREE frame -> reg#0
00001 IF-FALSE-GOTO 5
00002 READ_TREE fc -> reg#1
00003 IF-FALSE-GOTO 5
00004 ANY_EQ reg#0 == reg#1
00005 RETURN
--------
Filter: frame == :fc
Constants:
00000 PUT_FVALUE fc <FT_PROTOCOL> -> reg#1
Instructions:
00000 READ_TREE frame -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_EQ reg#0 == reg#1
00003 RETURN
The filter "frame == fc" is the same as "filter == .fc",
according to the current heuristic, except the first form
will try to parse it as a literal if the name does not
correspond to any registered protocol.
By treating a leading dot as a name in the language we
necessarily disallow writing floats with a leading dot. We
will also disallow writing with an ending dot when using
unparsed values. This is a backward incompatibility but has
the happy side effect of making the expression {1...2}
unambiguous.
This could either mean "1 .. .2" or "1. .. 2". If we require
a leading and ending digit then the meaning is clear:
1.0..0.2 -> 1.0 .. 0.2
Fixes#17731.
Add the option to enter a filter with an absolute time
value in UTC. Otherwise the value is interpreted in
local time.
The syntax used is an "UTC" suffix, for example:
frame.time == "Dec 31, 2002 13:55:31.3 UTC"
This also changes the behavior of "Apply Selected as filter".
Fields using a local time display type will use local time
and fields using UTC display type will be applied using UTC.
Fixes#13268.
To complete the set of equality operators add an "all equal"
operator that matches a frame if all fields match the condition.
The symbol chosen for "all_eq" is "===".
Use that for error messages, including any using test operators.
This allows to always use the same name as the user. It avoids
cases where the user write "a && b" and the message is "a and b"
is syntactically invalid.
It should also allow us to be more consistent with the use of
double quotes.
This reverts commit d635ff4933.
A charconst cannot be a value string, for that reason it is not
redundant with unparsed.
Maybe character constants should be parsed in the lexical scanner
instead.
Before:
Filter: ip.proto == '\g'
dftest: "'\g'" cannot be found among the possible values for ip.proto.
After:
Filter: ip.proto == '\g'
dftest: "'\g'" isn't a valid character constant.
For double quoted strings. This is consistent with single quote
character constants and the C standard. It also avoids common
mistakes where the superfluous backslash is silently suppressed.
A charconst uses the same semantic rules as unparsed so just
use the latter to avoid redundancies.
We keep the use of TOKEN_CHARCONST as an optimization to avoid
an unnecessary name resolution (lookup for a registered field with
the same name as the charconst).
Revert to the original design of having a single pattern to catch
everything as unparsed and also try to be less hackish and fragile
parsing "..".
Strings like "80..90" are tricky because it can be parsed as
INTEGER DOTDOT INTEGER or FLOAT FLOAT.
Deprecate the usage of significant whitespace to separate set elements
(or anywhere else for that matter). This will make the implementation
simpler and cleaner and the language more expressive and user-friendly.
Wireshark defines the relation of equality A == B as
A any_eq B <=> An == Bn for at least one An, Bn.
More accurately I think this is (formally) an equivalence
relation, not true equality.
Whichever definition for "==" we choose we must keep the
definition of "!=" as !(A == B), otherwise it will
lead to logical contradictions like (A == B) AND (A != B)
being true.
Fix the '!=' relation to match the definition of equality:
A != B <=> !(A == B) <=> A all_ne B <=> An != Bn, for
every n.
This has been the recomended way to write "not equal" for a
long time in the documentation, even to the point where != was
deprecated, but it just wasn't implemented consistently in the
language, which has understandably been a persistent source
of confusion. Even a field that is normally well-behaved
with "!=" like "ip.src" or "ip.dst" will produce unexpected
results with encapsulations like IP-over-IP.
The opcode ALL_NE could have been implemented in the compiler
instead using NOT and ANY_EQ but I chose to implement it in
bytecode. It just seemed more elegant and efficient
but the difference was not very significant.
Keep around "~=" for any_ne relation, in case someone depends
on that, and because we don't have an operator for true equality:
A strict_equal B <=> A all_eq B <=> !(A any_ne B).
If there is only one value then any_ne and all_ne are the same
comparison operation.
Implementing this change did not require fixing any tests so it
is unlikely the relation "~=" (any_ne) will be very useful.
Note that the behaviour of the '<' (less than) comparison relation
is a separate, more subtle issue. In the general case the definition
of '<' that is used is only a partial order.
Matches is a special case that looks on the RHS and tries
to convert every unparsed value to a string, regardless
of the LHS type. This is not how types work in the display
filter. Require double-quotes to avoid ambiguity, because
matches doesn't follow normal Wireshark display filter
type rules. It doesn't need nor benefit from the flexibility
provided by unparsed strings in the syntax.
For matches the RHS is always a literal strings except
if the RHS is also a field name, then it complains of an
incompatible type. This is confusing. No type can be compatible
because no type rules are ever considered. Every unparsed value is
a text string except if it happens to coincide with a field
name it also requires double-quoting or it throws a syntax error,
just to be difficult. We could remove this odd quirk but requiring
double-quotes for regular expressions is a better, more elegant
fix.
Before:
Filter: tcp matches "udp"
Constants:
00000 PUT_PCRE udp -> reg#1
Instructions:
00000 READ_TREE tcp -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_MATCHES reg#0 matches reg#1
00003 RETURN
Filter: tcp matches udp
Constants:
00000 PUT_PCRE udp -> reg#1
Instructions:
00000 READ_TREE tcp -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_MATCHES reg#0 matches reg#1
00003 RETURN
Filter: tcp matches udp.srcport
dftest: tcp and udp.srcport are not of compatible types.
Filter: tcp matches udp.srcportt
Constants:
00000 PUT_PCRE udp.srcportt -> reg#1
Instructions:
00000 READ_TREE tcp -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_MATCHES reg#0 matches reg#1
00003 RETURN
After:
Filter: tcp matches "udp"
Constants:
00000 PUT_PCRE udp -> reg#1
Instructions:
00000 READ_TREE tcp -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_MATCHES reg#0 matches reg#1
00003 RETURN
Filter: tcp matches udp
dftest: "udp" was unexpected in this context.
Filter: tcp matches udp.srcport
dftest: "udp.srcport" was unexpected in this context.
Filter: tcp matches udp.srcportt
dftest: "udp.srcportt" was unexpected in this context.
The error message could still be improved.
It won't work with embedded null bytes so don't try. This is
not an additional restriction, it just removes a hidden failure
mode. To support matching embedded NUL bytes we would have
to use an internal string representation other than
null-terminated C strings (which doesn't seem very onerous with
GString).
Before:
Filter: http.user_agent == 41:42:00:43
Constants:
00000 PUT_FVALUE "AB" <FT_STRING> -> reg#1
Instructions:
00000 READ_TREE http.user_agent -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_EQ reg#0 == reg#1
00003 RETURN
After:
Filter: http.user_agent == 41:42:00:43
Constants:
00000 PUT_FVALUE "41:42:00:43" <FT_STRING> -> reg#1
Instructions:
00000 READ_TREE http.user_agent -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_EQ reg#0 == reg#1
00003 RETURN
FT_PROTOCOL and FT_BYTES are the same semantic type, but one is
backed by a GByteArray and the other by a TVBuff. Use the same
semantic rules to parse both. In particular unparsed strings
are not converted to literal strings for protocols.
Before:
Filter: frame contains 0x0000
Constants:
00000 PUT_FVALUE 30:78:30:30:30:30 <FT_PROTOCOL> -> reg#1
Instructions:
00000 READ_TREE frame -> reg#0
00001 IF-FALSE-GOTO 3
00002 ANY_CONTAINS reg#0 contains reg#1
00003 RETURN
Filter: frame[5:] contains 0x0000
dftest: "0x0000" is not a valid byte string.
After:
Filter: frame contains 0x0000
dftest: "0x0000" is not a valid byte string.
Filter: frame[5:] contains 0x0000
dftest: "0x0000" is not a valid byte string.
Related to #17634.
If we have a STRING value in an expression and a numeric comparison
we must also check if it matches a value string before throwing
a type error.
Add appropriate tests to the test suite.
Fixes 4d2f469212.
Allow an entity in the grammar as range body. Perform a stronger
sanity check during semantic analysis everywhere a range is used.
This is both safer (unless we want to allow FIELD bodies only, but
functions are allowed too) and also provides better error messages.
Previously a range of range only compiled on the RHS. Now it can
appear on both sides of a relation.
This fixes a crash with STRING entities similar to #10690 for
UNPARSED.
This also adds back support for slicing functions that was removed
in f3f833ccec (by accident presumably).
Ping #10690
PEP 394[1] says,
"In cases where the script is expected to be executed outside virtual
environments, developers will need to be aware of the following
discrepancies across platforms and installation methods:
* Older Linux distributions will provide a python command that refers
to Python 2, and will likely not provide a python2 command.
* Some newer Linux distributions will provide a python command that
refers to Python 3.
* Some Linux distributions will not provide a python command at all by
default, but will provide a python3 command by default."
Debian has forced the issue by choosing the third option[2]:
"NOTE: Debian testing (bullseye) has removed the "python" package and
the '/usr/bin/python' symlink due to the deprecation of Python 2."
Switch our shebang from "#!/usr/bin/env python" to "#!/usr/bin/env
python3" in some places. Remove some 2/3 version checks if we know we're
running under Python 3. Remove the "coding: utf-8" in a bunch of places
since that's the default in Python 3.
[1]https://www.python.org/dev/peps/pep-0394/#for-python-script-publishers
[2]https://wiki.debian.org/Python
If a display filter contains a set for the set membership operator and
an error occurs, then gen_relation_in() (called via dfw_gencode() will
not take ownership of the set and a memory leak occurs.
Fix this by implementing a free callback for STTYPE_SET nodes which
frees unclaimed data. Add tests to verify the effectiveness, ASAN no
longer complains after this fix.
Bug: 15442
Change-Id: If37cf047660464b2d0304748034d0bc22111e5d6
Reviewed-on: https://code.wireshark.org/review/31758
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Instead of just reporting a mismatching error code, include the program
output. This should help tracking down unexpected errors. While at it,
check the expected error message too.
Change-Id: Ib8fe51cc06b795bb54bfe1e6eaa828c6ba1128ef
Reviewed-on: https://code.wireshark.org/review/31714
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Do not rely on strptime("%b") to parse the month, it does not correctly
recognize English month abbreviations on non-English systems. While at
it, do not try to parse milliseconds if seconds are missing.
Change-Id: Ia049bf362195eef1eba2f04ff7217049fa6a7d9d
Reviewed-on: https://code.wireshark.org/review/31707
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: João Valverde <j@v6e.pt>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
This function can convert non-string fields into strings. This allows the
user to apply string functions (like contains and matches) to non-string fields.
Examples:
string(frame.number) matches "[13579]$" => for odd frames
string(eth.dst) matches "aa\.bb\.cc\.dd\.ee\..." => to match a group of stations
string(snmp.name) matches "^1.2.3.4" => for all OIDs under a specific node
Change-Id: I18173f50ba5314ecdcd1e4b66c7e8ba5b44257ee
Reviewed-on: https://code.wireshark.org/review/31427
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
The buildbot detects random errors on Windows. Log some more details in
order to understand the problem better.
Change-Id: I903457894985273a63b8907b6784a2897cd93d93
Reviewed-on: https://code.wireshark.org/review/31340
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Stop using subprocesstest, drop the (now redundant) DFTestCase base
class and use pytest-style fixtures to inject the dependency on tshark.
This approach makes it easier to switch to pytest in the future.
Most substitutions were automated, so no typos should be present.
Change-Id: I3516029162f87423816937410ff63507ff82e96f
Reviewed-on: https://code.wireshark.org/review/30649
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
'double' tests have been disabled in aa03833 due to format change
in ntp fields.
Change-Id: Id3ab0a736c164bb7fdfed7b5da8856b512308978
Reviewed-on: https://code.wireshark.org/review/30366
Petri-Dish: Dario Lombardo <lomato@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
dfilter/group_double tests have been removed and need to be replaced by leveraging
another protocol.
Bug: 15049
Change-Id: I354a27a5217336ee5c9b1d021a2d3226e3532eec
Reviewed-on: https://code.wireshark.org/review/29035
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Michael Mann <mmann78@netscape.net>
Change the test suite list in CMakeLists.txt to a static list. Add a
CTest coverage unit test.
Change-Id: I8459f320a2d0707618d6d56abdfce80274fddd2d
Reviewed-on: https://code.wireshark.org/review/27377
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Gerald Combs <gerald@wireshark.org>
João Valverde