Add support for display filter binary addition and subtraction.
The grammar is intentionally kept simple for now. The use case
is to add a constant to a protocol field, or (maybe) add two
fields in an expression.
We use signed arithmetic with unsigned numbers, checking for
overflow and casting where necessary to do the conversion.
We could legitimately opt to use traditional modular arithmetic
instead (like C) and if it turns out that that is more useful for
some reason we may want to in the future.
Fixes#15504.
By the time we are using the reference fvalue the tree may have gone
away and with it the fvalue. We need to duplicate the reference
fvalues and take ownership of the memory.
This replaces the current macro reference system with
a completely different implementation. Instead of a macro a reference
is a syntax element. A reference is a constant that can be filled
in the dfilter code after compilation from an existing protocol tree.
It is best understood as a field value that can be read from a fixed
tree that is not the frame being filtered. Usually this fixed tree
is the currently selected frame when the filter is applied. This
allows comparing fields in the filtered frame with fields in the
selected frame.
Because the field reference syntax uses the same sigil notation
as a macro we have to use a heuristic to distinguish them:
if the name has a dot it is a field reference, otherwise
it is a macro name.
The reference is synctatically validated at compile time.
There are two main advantages to this implementation (and a couple of
minor ones):
The protocol tree for each selected frame is only walked if we have a
display filter and if the display filter uses references. Also only the
actual reference values are copied, intead of loading the entire tree
into a hash table (in textual form even).
The other advantage is that the reference is tested like a protocol
field against all the values in the selected frame (if there is more
than one).
Currently the reference fields are not "primed" during dissection, so
the entire tree is walked to find a particular reference (this is
similar to the previous implementation).
If the display filter contains a valid reference and the reference is
not loaded at the time the filter is run the result is the same as a
non existing field for a regular READ_TREE instruction.
Fixes#17599.
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 adds a _ws.ftypes namespace with protocol fields with all
the existing field types.
Currently this is only useful to debug the display filter compiler,
without having to find a real protocol field with the desired type.
Later it may find other uses.
Fix
ui/qt/models/filter_list_model.cpp:299:33: warning: implicit conversion loses integer precision: 'qsizetype' (aka 'long long') to 'int' [-Wshorten-64-to-32]
storage.move(strow, storeTo);
~~~~ ^~~~~~~
when building with Qt 5.
Fixes "make install" to be relocatable using DESTDIR. For that
we cannot use an absolute path as intallation directory target.
This is useful mostly to implement packaging using CPack.
It is a bit awkward to configure a default CMAKE_INSTALL_PREFIX
using WiresharkConfig.cmake but it seems to be working OK.
The previous non-relocatable behaviour may still be useful. It is
relegated to a custom "copy_plugin" target.
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.
Fix
** (wireshark:77415) 10:53:35.149736 [GUI WARNING] -- QObject::connect: No such signal QComboBox::currentIndexChanged(QString) in ui/qt/about_dialog.cpp:352
** (wireshark:77415) 10:53:35.149760 [GUI WARNING] -- QObject::connect: (sender name: 'cmbType')
Use new-style connections everywhere in about_dialog.cpp.
João Valverde