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Minor release notes clean up 

Add a new item about field references and reorganize the
list roughly by relevance.
This commit is contained in:
João Valverde 2022-05-22 20:18:15 +01:00
parent 94fe2b195c
commit 66506483bf
1 changed files with 28 additions and 22 deletions
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50
docbook/release-notes.adoc
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@ -24,6 +24,8 @@ wsbuglink:17779[]
* You must now have a compiler with C11 support in order to build Wireshark.
* Display filter syntax is now more powerful with several new extensions.
Many improvements have been made.
See the “New and Updated Features” section below for more details.
@ -54,6 +56,29 @@ They previously shipped with Qt 5.12.2.
* The display filter syntax has been updated and enhanced:
** A syntax to match a specific layer in the protocol stack has been added.
For example “ip.addr#2 == 1.1.1.1” matches only the inner layer in an IP-over-IP packet.
** Universal quantifiers "any" and "all" have been added to any relational operator.
For example the expression "all tcp.port > 1024" is true if and only if all tcp.port fields match the condition.
Previously only the default behaviour to return true if any one field matches was supported.
** Field references, of the form ${some.field}, are now part of the syntax of display filters. Previously they were implemented as macros.
The new implementation is more efficient and allows matching multiple values, like any other protocol field.
** Arithmetic is supported for numeric fields with the usual operators “+”, “-”, “*”, “/”, and “%”.
Arithmetic expressions must be grouped using curly brackets (not parenthesis).
** New display filter functions max(), min() and abs() have been added.
** Functions can accept expressions as arguments, including other functions.
Previously only protocol fields and slices were syntactically valid function arguments.
** A new syntax to disambiguate literals from identifiers has been added.
Every value with a leading dot is a protocol or protocol field.
Every value in between angle brackets is a literal value.
See the https://www.wireshark.org/docs/wsug_html_chunked/ChWorkBuildDisplayFilterSection.html#_some_protocol_names_can_be_ambiguous[User’s Guide] for details.
** The "bitwise and" operator is now a first-class bit operator, not a boolean operator.
In particular this means it is now possible to mask bits, e.g.: frame[0] & 0x0F == 3.
** Dates and times can be given in UTC using ISO 8601 (with 'Z' timezone) or by appending the suffix "UTC" to the legacy formats.
Otherwise local time is used.
** Integer literal constants may be written in binary (in addition to decimal/octal/hexadecimal) using the prefix "0b" or "0B".
** Logical AND now has higher precedence than logical OR, in line with most programming languages.
** It is now possible to index protocol fields from the end using negative indexes. For example the
following expression tests the last two bytes of the TCP protocol field: tcp[-2:] == AA:BB.
This was a longstanding bug that has been fixed in this release.
** Set elements must be separated using a comma, e.g: {1, 2, "foo"}.
Using only whitespace as a separator was deprecated in 3.6 and is now a syntax error.
** Support for some additional character escape sequences in double quoted strings has been added.
@ -62,37 +87,18 @@ They previously shipped with Qt 5.12.2.
** Unrecognized escape sequences are now treated as a syntax error.
Previously they were treated as a literal character.
In addition to the sequences indicated above, backslash, single quotation and double quotation mark are also valid sequences: \\, \', \".
** The display filter engine now uses PCRE2 instead of GRegex (GLib’s bindings to the older and end-of-life PCRE library).
PCRE2 is compatible with PCRE so any user-visible changes should be minimal.
Some exotic patterns may now be invalid and require rewriting.
** A new strict equality operator "===" or "all_eq" has been added.
The expression "a === b" is true if and only if all a’s are equal to b.
The negation of "===" can now be written as "!==" (any_ne).
** The aliases "any_eq" for "==" and "all_ne" for "!=" have been added.
** The operator "~=" is deprecated and will be removed in a future version.
Use "!==", which has the same meaning instead.
** Dates and times can be given in UTC using ISO 8601 (with 'Z' timezone) or by appending the suffix "UTC" to the legacy formats.
Otherwise local time is used.
** Integer literal constants may be written in binary (in addition to decimal/octal/hexadecimal) using the prefix "0b" or "0B".
** A new syntax to disambiguate literals from identifiers has been added.
Every value with a leading dot is a protocol or protocol field.
Every value with a leading colon or in between angle brackets is a literal value.
See the https://www.wireshark.org/docs/wsug_html_chunked/ChWorkBuildDisplayFilterSection.html#_some_protocol_names_can_be_ambiguous[User’s Guide] for details.
** Floats must be written with a leading and ending digit.
For example the values ".7" and "7." are now invalid as floats.
They must be written "0.7" and "7.0" respectively.
** The "bitwise and" operator is now a first-class bit operator, not a boolean operator.
In particular this means it is now possible to mask bits, e.g.: frame[0] & 0x0F == 3.
** Arithmetic is supported for numeric fields with the usual operators “+”, “-”, “*”, “/”, and “%”.
Arithmetic expressions must be grouped using curly brackets (not parenthesis).
** Logical AND now has higher precedence than logical OR, in line with most programming languages.
** New display filter functions max(), min() and abs() have been added.
** Functions can accept expressions as arguments, including other functions.
Previously only protocol fields and slices were syntactically valid function arguments.
** Adds the universal quantifiers "any" and "all" to any relational operator: all tcp.port > 1024.
** It is now possible to index protocol fields from the end using negative indexes. For example the
following expression tests the last two bytes of the TCP protocol field: tcp[-2:] == AA:BB.
This was a longstanding bug that has been fixed in this release.
** The display filter engine now uses PCRE2 instead of GRegex (GLib’s bindings to the older and end-of-life PCRE library).
PCRE2 is compatible with PCRE so any user-visible changes should be minimal.
Some exotic patterns may now be invalid and require rewriting.
* The `text2pcap` command and the “Import from Hex Dump” feature have been updated and enhanced:
** `text2pcap` supports writing the output file in all the capture file formats that wiretap library supports, using the same `-F` option as `editcap`, `mergecap`, and `tshark`.