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REAME.dissector: remove double spaces. 

Change-Id: I87b9748bb14b148cfc7ffdc5fd5d9059fa2d2299
Reviewed-on: https://code.wireshark.org/review/33522
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Dario Lombardo 2019-06-08 22:53:52 +02:00 committed by Anders Broman
parent e44d4e740e
commit 14553ee358
1 changed files with 149 additions and 149 deletions
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doc/README.dissector
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@ -51,7 +51,7 @@ add to the protocol tree, and work with registered header fields.
Wireshark requires certain things when setting up a protocol dissector. Wireshark requires certain things when setting up a protocol dissector.
We provide basic skeleton code for a dissector that you can copy to a new file We provide basic skeleton code for a dissector that you can copy to a new file
and fill in. Your dissector should follow the naming convention of "packet-" and fill in. Your dissector should follow the naming convention of "packet-"
followed by the abbreviated name for the protocol. It is recommended that where followed by the abbreviated name for the protocol. It is recommended that where
possible you keep to the IANA abbreviated name for the protocol, if there is possible you keep to the IANA abbreviated name for the protocol, if there is
one, or a commonly-used abbreviation for the protocol, if any. one, or a commonly-used abbreviation for the protocol, if any.
@ -84,7 +84,7 @@ need to include additional headers.
In the skeleton sample code the following strings should be substituted with In the skeleton sample code the following strings should be substituted with
your information. your information.
YOUR_NAME Your name, of course. You do want credit, don't you? YOUR_NAME Your name, of course. You do want credit, don't you?
It's the only payment you will receive.... It's the only payment you will receive....
YOUR_EMAIL_ADDRESS Keep those cards and letters coming. YOUR_EMAIL_ADDRESS Keep those cards and letters coming.
PROTONAME The name of the protocol; this is displayed in the PROTONAME The name of the protocol; this is displayed in the
@ -125,8 +125,8 @@ FIELDDISPLAY --For FT_UINT{8,16,24,32,40,48,56,64} and
filters for the field in question. filters for the field in question.
BASE_NO_DISPLAY_VALUE will just display the field name with BASE_NO_DISPLAY_VALUE will just display the field name with
no value. It is intended for byte arrays (FT_BYTES or no value. It is intended for byte arrays (FT_BYTES or
FT_UINT_BYTES) or header fields above a subtree. The FT_UINT_BYTES) or header fields above a subtree. The
value will still be filterable, just not displayed. value will still be filterable, just not displayed.
--For FT_UINT16: --For FT_UINT16:
@ -192,7 +192,7 @@ BITMASK Used to mask a field not 8-bit aligned or with a size other
FIELDDESCR A brief description of the field, or NULL. [Please do not use ""]. FIELDDESCR A brief description of the field, or NULL. [Please do not use ""].
If, for example, PROTONAME is "Internet Bogosity Discovery Protocol", If, for example, PROTONAME is "Internet Bogosity Discovery Protocol",
PROTOSHORTNAME would be "IBDP", and PROTOABBREV would be "ibdp". Try to PROTOSHORTNAME would be "IBDP", and PROTOABBREV would be "ibdp". Try to
conform with IANA names. conform with IANA names.
1.3 The dissector and the data it receives. 1.3 The dissector and the data it receives.
@ -218,7 +218,7 @@ NOTE: See the file /epan/tvbuff.h for more details.
The "tvb" argument to a dissector points to a buffer containing the raw The "tvb" argument to a dissector points to a buffer containing the raw
data to be analyzed by the dissector; for example, for a protocol data to be analyzed by the dissector; for example, for a protocol
running atop UDP, it contains the UDP payload (but not the UDP header, running atop UDP, it contains the UDP payload (but not the UDP header,
or any protocol headers above it). A tvbuffer is an opaque data or any protocol headers above it). A tvbuffer is an opaque data
structure, the internal data structures are hidden and the data must be structure, the internal data structures are hidden and the data must be
accessed via the tvbuffer accessors. accessed via the tvbuffer accessors.
@ -373,7 +373,7 @@ guint32 tvb_get_ipv4(tvbuff_t *tvb, const gint offset);
void tvb_get_ipv6(tvbuff_t *tvb, const gint offset, ws_in6_addr *addr); void tvb_get_ipv6(tvbuff_t *tvb, const gint offset, ws_in6_addr *addr);
NOTE: IPv4 addresses are not to be converted to host byte order before NOTE: IPv4 addresses are not to be converted to host byte order before
being passed to "proto_tree_add_ipv4()". You should use "tvb_get_ipv4()" being passed to "proto_tree_add_ipv4()". You should use "tvb_get_ipv4()"
to fetch them, not "tvb_get_ntohl()" *OR* "tvb_get_letohl()" - don't, to fetch them, not "tvb_get_ntohl()" *OR* "tvb_get_letohl()" - don't,
for example, try to use "tvb_get_ntohl()", find that it gives you the for example, try to use "tvb_get_ntohl()", find that it gives you the
wrong answer on the PC on which you're doing development, and try wrong answer on the PC on which you're doing development, and try
@ -409,9 +409,9 @@ guint8 *tvb_get_stringz_enc(wmem_allocator_t *scope, tvbuff_t *tvb, const gint o
Returns a null-terminated buffer allocated from the specified scope, Returns a null-terminated buffer allocated from the specified scope,
containing data from the specified tvbuff, starting at the specified containing data from the specified tvbuff, starting at the specified
offset, and containing all characters from the tvbuff up to and offset, and containing all characters from the tvbuff up to and
including a terminating null character in the tvbuff. Reads data in the including a terminating null character in the tvbuff. Reads data in the
specified encoding and produces UTF-8 in the buffer. See below for a specified encoding and produces UTF-8 in the buffer. See below for a
list of input encoding values. "*lengthp" will be set to the length of list of input encoding values. "*lengthp" will be set to the length of
the string, including the terminating null. the string, including the terminating null.
The buffer is allocated in the given wmem scope (see README.wmem for more The buffer is allocated in the given wmem scope (see README.wmem for more
@ -422,11 +422,11 @@ const guint8 *tvb_get_const_stringz(tvbuff_t *tvb, const gint offset, gint *leng
Returns a null-terminated const buffer containing data from the Returns a null-terminated const buffer containing data from the
specified tvbuff, starting at the specified offset, and containing all specified tvbuff, starting at the specified offset, and containing all
bytes from the tvbuff up to and including a terminating null character bytes from the tvbuff up to and including a terminating null character
in the tvbuff. "*lengthp" will be set to the length of the string, in the tvbuff. "*lengthp" will be set to the length of the string,
including the terminating null. including the terminating null.
You do not need to free() this buffer; it will happen automatically once You do not need to free() this buffer; it will happen automatically once
the next packet is dissected. This function is slightly more efficient the next packet is dissected. This function is slightly more efficient
than the others because it does not allocate memory and copy the string, than the others because it does not allocate memory and copy the string,
but it does not do any mapping to UTF-8 or checks for valid octet but it does not do any mapping to UTF-8 or checks for valid octet
sequences. sequences.
@ -502,10 +502,10 @@ Returns a buffer containing a copy of the given TVB bytes. The buffer is
allocated in the given wmem scope (see README.wmem for more information). allocated in the given wmem scope (see README.wmem for more information).
Pointer-retrieval: Pointer-retrieval:
/* WARNING! Don't use this function. There is almost always a better way. /* WARNING! Don't use this function. There is almost always a better way.
* It's dangerous because once this pointer is given to the user, there's * It's dangerous because once this pointer is given to the user, there's
* no guarantee that the user will honor the 'length' and not overstep the * no guarantee that the user will honor the 'length' and not overstep the
* boundaries of the buffer. Also see the warning in the Portability section. * boundaries of the buffer. Also see the warning in the Portability section.
*/ */
const guint8* tvb_get_ptr(tvbuff_t *tvb, const gint offset, const gint length); const guint8* tvb_get_ptr(tvbuff_t *tvb, const gint offset, const gint length);
@ -545,7 +545,7 @@ argument, and the COL_ value for the column as their second argument.
1.4.1 The col_set_str function. 1.4.1 The col_set_str function.
'col_set_str' takes a string as its third argument, and sets the value 'col_set_str' takes a string as its third argument, and sets the value
for the column to that value. It assumes that the pointer passed to it for the column to that value. It assumes that the pointer passed to it
points to a string constant or a static "const" array, not to a points to a string constant or a static "const" array, not to a
variable, as it doesn't copy the string, it merely saves the pointer variable, as it doesn't copy the string, it merely saves the pointer
value; the argument can itself be a variable, as long as it always value; the argument can itself be a variable, as long as it always
@ -566,7 +566,7 @@ to "PROTOABBREV":
1.4.2 The col_add_str function. 1.4.2 The col_add_str function.
'col_add_str' takes a string as its third argument, and sets the value 'col_add_str' takes a string as its third argument, and sets the value
for the column to that value. It takes the same arguments as for the column to that value. It takes the same arguments as
'col_set_str', but copies the string, so that if the string is, for 'col_set_str', but copies the string, so that if the string is, for
example, an automatic variable that won't remain in scope when the example, an automatic variable that won't remain in scope when the
dissector returns, it's safe to use. dissector returns, it's safe to use.
@ -576,7 +576,7 @@ dissector returns, it's safe to use.
'col_add_fstr' takes a 'printf'-style format string as its third 'col_add_fstr' takes a 'printf'-style format string as its third
argument, and 'printf'-style arguments corresponding to '%' format argument, and 'printf'-style arguments corresponding to '%' format
items in that string as its subsequent arguments. For example, to set items in that string as its subsequent arguments. For example, to set
the "Info" field to "<XXX> request, <N> bytes", where "reqtype" is a the "Info" field to "<XXX> request, <N> bytes", where "reqtype" is a
string containing the type of the request in the packet and "n" is an string containing the type of the request in the packet and "n" is an
unsigned integer containing the number of bytes in the request: unsigned integer containing the number of bytes in the request:
@ -594,7 +594,7 @@ efficiently.
If the Info column will be filled with information from the packet, that If the Info column will be filled with information from the packet, that
means that some data will be fetched from the packet before the Info means that some data will be fetched from the packet before the Info
column is filled in. If the packet is so small that the data in column is filled in. If the packet is so small that the data in
question cannot be fetched, the routines to fetch the data will throw an question cannot be fetched, the routines to fetch the data will throw an
exception (see the comment at the beginning about tvbuffers improving exception (see the comment at the beginning about tvbuffers improving
the handling of short packets - the tvbuffers keep track of how much the handling of short packets - the tvbuffers keep track of how much
@ -634,10 +634,10 @@ string after it's fetched the data to use when doing that.
Sometimes the value of a column, especially the "Info" column, can't be Sometimes the value of a column, especially the "Info" column, can't be
conveniently constructed at a single point in the dissection process; conveniently constructed at a single point in the dissection process;
for example, it might contain small bits of information from many of the for example, it might contain small bits of information from many of the
fields in the packet. 'col_append_str' takes, as arguments, the same fields in the packet. 'col_append_str' takes, as arguments, the same
arguments as 'col_add_str', but the string is appended to the end of the arguments as 'col_add_str', but the string is appended to the end of the
current value for the column, rather than replacing the value for that current value for the column, rather than replacing the value for that
column. (Note that no blank separates the appended string from the column. (Note that no blank separates the appended string from the
string to which it is appended; if you want a blank there, you must add string to which it is appended; if you want a blank there, you must add
it yourself as part of the string being appended.) it yourself as part of the string being appended.)
@ -663,7 +663,7 @@ identical to what 'col_append_str' and 'col_append_fstr' do.
Sometimes a dissector may be called multiple times for different PDUs in the Sometimes a dissector may be called multiple times for different PDUs in the
same frame (for example in the case of SCTP chunk bundling: several upper same frame (for example in the case of SCTP chunk bundling: several upper
layer data packets may be contained in one SCTP packet). If the upper layer layer data packets may be contained in one SCTP packet). If the upper layer
dissector calls 'col_set_str()' or 'col_clear()' on the Info column when it dissector calls 'col_set_str()' or 'col_clear()' on the Info column when it
begins dissecting each of those PDUs then when the frame is fully dissected begins dissecting each of those PDUs then when the frame is fully dissected
the Info column would contain only the string from the last PDU in the frame. the Info column would contain only the string from the last PDU in the frame.
@ -673,7 +673,7 @@ For example, the SCTP dissector calls 'col_set_fence' on the Info column
after it has called any subdissectors for that chunk so that subdissectors after it has called any subdissectors for that chunk so that subdissectors
of any subsequent chunks may only append to the Info column. of any subsequent chunks may only append to the Info column.
'col_prepend_fence_fstr' prepends data before a fence (moving it if 'col_prepend_fence_fstr' prepends data before a fence (moving it if
necessary). It will create a fence at the end of the prepended data if the necessary). It will create a fence at the end of the prepended data if the
fence does not already exist. fence does not already exist.
@ -711,7 +711,7 @@ proto_tree_draw().
The logical proto_tree needs to know detailed information about the protocols The logical proto_tree needs to know detailed information about the protocols
and fields about which information will be collected from the dissection and fields about which information will be collected from the dissection
routines. By strictly defining (or "typing") the data that can be attached to a routines. By strictly defining (or "typing") the data that can be attached to a
proto tree, searching and filtering becomes possible. This means that for proto tree, searching and filtering becomes possible. This means that for
every protocol and field (which I also call "header fields", since they are every protocol and field (which I also call "header fields", since they are
fields in the protocol headers) which might be attached to a tree, some fields in the protocol headers) which might be attached to a tree, some
information is needed. information is needed.
@ -726,7 +726,7 @@ registration of protocols and fields at run-time, loadable modules of
protocol dissectors (perhaps even user-supplied) is feasible. protocol dissectors (perhaps even user-supplied) is feasible.
To do this, each protocol should have a register routine, which will be To do this, each protocol should have a register routine, which will be
called when Wireshark starts. The code to call the register routines is called when Wireshark starts. The code to call the register routines is
generated automatically; to arrange that a protocol's register routine generated automatically; to arrange that a protocol's register routine
be called at startup: be called at startup:
@ -805,20 +805,20 @@ struct header_field_info {
name (FIELDNAME) name (FIELDNAME)
---------------- ----------------
A string representing the name of the field. This is the name A string representing the name of the field. This is the name
that will appear in the graphical protocol tree. It must be a non-empty that will appear in the graphical protocol tree. It must be a non-empty
string. string.
abbrev (FIELDABBREV) abbrev (FIELDABBREV)
-------------------- --------------------
A string with an abbreviation of the field. The abbreviation should start A string with an abbreviation of the field. The abbreviation should start
with the abbreviation of the parent protocol followed by a period as a with the abbreviation of the parent protocol followed by a period as a
separator. For example, the "src" field in an IP packet would have "ip.src" separator. For example, the "src" field in an IP packet would have "ip.src"
as an abbreviation. It is acceptable to have multiple levels of periods if, as an abbreviation. It is acceptable to have multiple levels of periods if,
for example, you have fields in your protocol that are then subdivided into for example, you have fields in your protocol that are then subdivided into
subfields. For example, TRMAC has multiple error fields, so the abbreviations subfields. For example, TRMAC has multiple error fields, so the abbreviations
follow this pattern: "trmac.errors.iso", "trmac.errors.noniso", etc. follow this pattern: "trmac.errors.iso", "trmac.errors.noniso", etc.
The abbreviation is the identifier used in a display filter. As such it The abbreviation is the identifier used in a display filter. As such it
cannot be an empty string. cannot be an empty string.
type (FIELDTYPE) type (FIELDTYPE)
@ -843,7 +843,7 @@ The type of value this field holds. The current field types are:
FT_FRAMENUM A frame number; if this is used, the "Go FT_FRAMENUM A frame number; if this is used, the "Go
To Corresponding Frame" menu item can To Corresponding Frame" menu item can
work on that field. work on that field.
FT_CHAR An 8-bit ASCII character. It's treated similarly to an FT_CHAR An 8-bit ASCII character. It's treated similarly to an
FT_UINT8, but is displayed as a C-style character FT_UINT8, but is displayed as a C-style character
constant. constant.
FT_UINT8 An 8-bit unsigned integer. FT_UINT8 An 8-bit unsigned integer.
@ -921,12 +921,12 @@ signed integers; the number on the end represent how many bits are used
to represent the number. to represent the number.
Some constraints are imposed on the header fields depending on the type Some constraints are imposed on the header fields depending on the type
(e.g. FT_BYTES) of the field. Fields of type FT_ABSOLUTE_TIME must use (e.g. FT_BYTES) of the field. Fields of type FT_ABSOLUTE_TIME must use
'ABSOLUTE_TIME_{LOCAL,UTC,DOY_UTC}, NULL, 0x0' as values for the 'ABSOLUTE_TIME_{LOCAL,UTC,DOY_UTC}, NULL, 0x0' as values for the
'display, 'strings', and 'bitmask' fields, and all other non-integral 'display, 'strings', and 'bitmask' fields, and all other non-integral
types (i.e.. types that are _not_ FT_INT* and FT_UINT*) must use types (i.e.. types that are _not_ FT_INT* and FT_UINT*) must use
'BASE_NONE, NULL, 0x0' as values for the 'display', 'strings', 'bitmask' 'BASE_NONE, NULL, 0x0' as values for the 'display', 'strings', 'bitmask'
fields. The reason is simply that the type itself implicitly defines the fields. The reason is simply that the type itself implicitly defines the
nature of 'display', 'strings', 'bitmask'. nature of 'display', 'strings', 'bitmask'.
display (FIELDDISPLAY) display (FIELDDISPLAY)
@ -937,7 +937,7 @@ makes for cleaner programs. Right now I still think that overloading
this variable was okay. this variable was okay.
For integer fields (FT_UINT* and FT_INT*), this variable represents the For integer fields (FT_UINT* and FT_INT*), this variable represents the
base in which you would like the value displayed. The acceptable bases base in which you would like the value displayed. The acceptable bases
are: are:
BASE_DEC, BASE_DEC,
@ -982,7 +982,7 @@ wide the parent bitfield is). (If the FT_BOOLEAN 'bitmask' is zero, then
For integer fields a "field-width" is not needed since the type of For integer fields a "field-width" is not needed since the type of
integer itself (FT_UINT8, FT_UINT16, FT_UINT24, FT_UINT32, FT_UINT40, integer itself (FT_UINT8, FT_UINT16, FT_UINT24, FT_UINT32, FT_UINT40,
FT_UINT48, FT_UINT56, FT_UINT64, etc) tells the proto_tree how wide the FT_UINT48, FT_UINT56, FT_UINT64, etc) tells the proto_tree how wide the
parent bitfield is. The same is true of FT_CHAR, as it's an 8-bit parent bitfield is. The same is true of FT_CHAR, as it's an 8-bit
character. character.
For FT_ABSOLUTE_TIME fields, 'display' is used to indicate whether the For FT_ABSOLUTE_TIME fields, 'display' is used to indicate whether the
@ -993,7 +993,7 @@ date should be displayed as "{monthname} {day_of_month}, {year}" or as
Additionally, BASE_NONE is used for 'display' as a NULL-value. That is, for Additionally, BASE_NONE is used for 'display' as a NULL-value. That is, for
non-integers other than FT_ABSOLUTE_TIME fields, and non-bitfield non-integers other than FT_ABSOLUTE_TIME fields, and non-bitfield
FT_BOOLEANs, you'll want to use BASE_NONE in the 'display' field. You may FT_BOOLEANs, you'll want to use BASE_NONE in the 'display' field. You may
not use BASE_NONE for integers. not use BASE_NONE for integers.
It is possible that in the future we will record the endianness of It is possible that in the future we will record the endianness of
@ -1008,7 +1008,7 @@ strings (FIELDCONVERT)
---------------------- ----------------------
-- value_string -- value_string
Some integer fields, of type FT_UINT*, need labels to represent the true Some integer fields, of type FT_UINT*, need labels to represent the true
value of a field. You could think of those fields as having an value of a field. You could think of those fields as having an
enumerated data type, rather than an integral data type. enumerated data type, rather than an integral data type.
A 'value_string' structure is a way to map values to strings. A 'value_string' structure is a way to map values to strings.
@ -1027,7 +1027,7 @@ For fields of that type, you would declare an array of "value_string"s:
}; };
(the last entry in the array must have a NULL 'strptr' value, to (the last entry in the array must have a NULL 'strptr' value, to
indicate the end of the array). The 'strings' field would be set to indicate the end of the array). The 'strings' field would be set to
'VALS(valstringname)'. 'VALS(valstringname)'.
If the field has a numeric rather than an enumerated type, the 'strings' If the field has a numeric rather than an enumerated type, the 'strings'
@ -1035,7 +1035,7 @@ field would be set to NULL.
If BASE_SPECIAL_VALS is also applied to the display bitmask, then if the If BASE_SPECIAL_VALS is also applied to the display bitmask, then if the
numeric value of a field doesn't match any values in the value_string numeric value of a field doesn't match any values in the value_string
then just the numeric value is displayed (i.e. no "Unknown"). This is then just the numeric value is displayed (i.e. no "Unknown"). This is
intended for use when the value_string only gives special names for intended for use when the value_string only gives special names for
certain field values and values not in the value_string are expected. certain field values and values not in the value_string are expected.
@ -1161,7 +1161,7 @@ ORed with 'BASE_RANGE_STRING' (e.g. BASE_DEC|BASE_RANGE_STRING).
-- Booleans -- Booleans
FT_BOOLEANs have a default map of 0 = "False", 1 (or anything else) = "True". FT_BOOLEANs have a default map of 0 = "False", 1 (or anything else) = "True".
Sometimes it is useful to change the labels for boolean values (e.g., Sometimes it is useful to change the labels for boolean values (e.g.,
to "Yes"/"No", "Fast"/"Slow", etc.). For these mappings, a struct called to "Yes"/"No", "Fast"/"Slow", etc.). For these mappings, a struct called
true_false_string is used. true_false_string is used.
typedef struct true_false_string { typedef struct true_false_string {
@ -1178,7 +1178,7 @@ labels, you would declare a "true_false_string"s:
}; };
Its two fields are pointers to the string representing truth, and the Its two fields are pointers to the string representing truth, and the
string representing falsehood. For FT_BOOLEAN fields that need a string representing falsehood. For FT_BOOLEAN fields that need a
'true_false_string' struct, the 'strings' field would be set to 'true_false_string' struct, the 'strings' field would be set to
'TFS(&boolstringname)'. 'TFS(&boolstringname)'.
@ -1211,7 +1211,7 @@ If the field is not a bitfield, then bitmask should be set to 0.
blurb (FIELDDESCR) blurb (FIELDDESCR)
------------------ ------------------
This is a string giving a proper description of the field. It should be This is a string giving a proper description of the field. It should be
at least one grammatically complete sentence, or NULL in which case the at least one grammatically complete sentence, or NULL in which case the
name field is used. (Please do not use ""). name field is used. (Please do not use "").
@ -1318,7 +1318,7 @@ created under an item made by any of the "proto_tree_add_XXX" functions,
so that the tree can be given an arbitrary depth. so that the tree can be given an arbitrary depth.
Subtree types are integers, assigned by Subtree types are integers, assigned by
"proto_register_subtree_array()". To register subtree types, pass an "proto_register_subtree_array()". To register subtree types, pass an
array of pointers to "gint" variables to hold the subtree type values to array of pointers to "gint" variables to hold the subtree type values to
"proto_register_subtree_array()": "proto_register_subtree_array()":
@ -1633,7 +1633,7 @@ protocol or field labels to the proto_tree:
proto_tree_add_ts_23_038_7bits_item(tree, hf_index, tvb, proto_tree_add_ts_23_038_7bits_item(tree, hf_index, tvb,
bit_offset, no_of_chars); bit_offset, no_of_chars);
The 'tree' argument is the tree to which the item is to be added. The The 'tree' argument is the tree to which the item is to be added. The
'tvb' argument is the tvbuff from which the item's value is being 'tvb' argument is the tvbuff from which the item's value is being
extracted; the 'start' argument is the offset from the beginning of that extracted; the 'start' argument is the offset from the beginning of that
tvbuff of the item being added, and the 'length' argument is the length, tvbuff of the item being added, and the 'length' argument is the length,
@ -1654,7 +1654,7 @@ proto_tree_add_item()
--------------------- ---------------------
proto_tree_add_item is used when you wish to do no special formatting. proto_tree_add_item is used when you wish to do no special formatting.
The item added to the GUI tree will contain the name (as passed in the The item added to the GUI tree will contain the name (as passed in the
proto_register_*() function) and a value. The value will be fetched proto_register_*() function) and a value. The value will be fetched
from the tvbuff by proto_tree_add_item(), based on the type of the field from the tvbuff by proto_tree_add_item(), based on the type of the field
and the encoding of the value as specified by the "encoding" argument. and the encoding of the value as specified by the "encoding" argument.
@ -1673,18 +1673,18 @@ argument should be ENC_LITTLE_ENDIAN if the value is little-endian
and ENC_BIG_ENDIAN if it is big-endian. and ENC_BIG_ENDIAN if it is big-endian.
For FT_IPv4 fields, the encoding also specifies the byte order of the For FT_IPv4 fields, the encoding also specifies the byte order of the
value. In almost all cases, the encoding is in network byte order, value. In almost all cases, the encoding is in network byte order,
hence big-endian, but in at least one protocol dissected by Wireshark, hence big-endian, but in at least one protocol dissected by Wireshark,
at least one IPv4 address is byte-swapped, so it's in little-endian at least one IPv4 address is byte-swapped, so it's in little-endian
order. order.
For string fields, the encoding specifies the character set used for the For string fields, the encoding specifies the character set used for the
string and the way individual code points in that character set are string and the way individual code points in that character set are
encoded. For FT_UINT_STRING fields, the byte order of the count must be encoded. For FT_UINT_STRING fields, the byte order of the count must be
specified; for UCS-2 and UTF-16, the byte order of the encoding must be specified; for UCS-2 and UTF-16, the byte order of the encoding must be
specified (for counted UCS-2 and UTF-16 strings, the byte order of the specified (for counted UCS-2 and UTF-16 strings, the byte order of the
count and the 16-bit values in the string must be the same). In other count and the 16-bit values in the string must be the same). In other
cases, ENC_NA should be used. The character encodings that are cases, ENC_NA should be used. The character encodings that are
currently supported are: currently supported are:
ENC_ASCII - ASCII (currently treated as UTF-8; in the future, ENC_ASCII - ASCII (currently treated as UTF-8; in the future,
@ -1723,21 +1723,21 @@ currently supported are:
Other encodings will be added in the future. Other encodings will be added in the future.
For FT_ABSOLUTE_TIME fields, the encoding specifies the form in which For FT_ABSOLUTE_TIME fields, the encoding specifies the form in which
the time stamp is specified, as well as its byte order. The time stamp the time stamp is specified, as well as its byte order. The time stamp
encodings that are currently supported are: encodings that are currently supported are:
ENC_TIME_SECS_NSECS - 8, 12, or 16 bytes. For 8 bytes, the first 4 ENC_TIME_SECS_NSECS - 8, 12, or 16 bytes. For 8 bytes, the first 4
bytes are seconds and the next 4 bytes are nanoseconds; for 12 bytes are seconds and the next 4 bytes are nanoseconds; for 12
bytes, the first 8 bytes are seconds and the next 4 bytes are bytes, the first 8 bytes are seconds and the next 4 bytes are
nanoseconds; for 16 bytes, the first 8 bytes are seconds and nanoseconds; for 16 bytes, the first 8 bytes are seconds and
the next 8 bytes are nanoseconds. The seconds are seconds the next 8 bytes are nanoseconds. The seconds are seconds
since the UN*X epoch (1970-01-01 00:00:00 UTC). (I.e., a UN*X since the UN*X epoch (1970-01-01 00:00:00 UTC). (I.e., a UN*X
struct timespec with a 4-byte or 8-byte time_t or a structure struct timespec with a 4-byte or 8-byte time_t or a structure
with an 8-byte time_t and an 8-byte nanoseconds field.) with an 8-byte time_t and an 8-byte nanoseconds field.)
ENC_TIME_NTP - 8 bytes; the first 4 bytes are seconds since the NTP ENC_TIME_NTP - 8 bytes; the first 4 bytes are seconds since the NTP
epoch (1900-01-01 00:00:00 GMT) and the next 4 bytes are 1/2^32's of epoch (1900-01-01 00:00:00 GMT) and the next 4 bytes are 1/2^32's of
a second since that second. (I.e., a 64-bit count of 1/2^32's of a a second since that second. (I.e., a 64-bit count of 1/2^32's of a
second since the NTP epoch, with the upper 32 bits first and the second since the NTP epoch, with the upper 32 bits first and the
lower 32 bits second, even when little-endian.) lower 32 bits second, even when little-endian.)
@ -1746,13 +1746,13 @@ encodings that are currently supported are:
ENC_TIME_RTPS - 8 bytes; the first 4 bytes are seconds since the UN*X ENC_TIME_RTPS - 8 bytes; the first 4 bytes are seconds since the UN*X
epoch and the next 4 bytes are are 1/2^32's of a second since that epoch and the next 4 bytes are are 1/2^32's of a second since that
second. (I.e., it's the offspring of a mating between UN*X time and second. (I.e., it's the offspring of a mating between UN*X time and
NTP time.) It's used by the Object Management Group's Real-Time NTP time). It's used by the Object Management Group's Real-Time
Publish-Subscribe Wire Protocol for the Data Distribution Service. Publish-Subscribe Wire Protocol for the Data Distribution Service.
ENC_TIME_SECS_USECS - 8 bytes; the first 4 bytes are seconds since the ENC_TIME_SECS_USECS - 8 bytes; the first 4 bytes are seconds since the
UN*X epoch and the next 4 bytes are microseconds since that UN*X epoch and the next 4 bytes are microseconds since that
second. (I.e., a UN*X struct timeval with a 4-byte time_t.) second. (I.e., a UN*X struct timeval with a 4-byte time_t.)
ENC_TIME_SECS - 4 to 8 bytes, representing a value in seconds since ENC_TIME_SECS - 4 to 8 bytes, representing a value in seconds since
the UN*X epoch. the UN*X epoch.
@ -1761,20 +1761,20 @@ encodings that are currently supported are:
since the UN*X epoch. since the UN*X epoch.
ENC_TIME_SECS_NTP - 4 bytes, representing a count of seconds since ENC_TIME_SECS_NTP - 4 bytes, representing a count of seconds since
the NTP epoch. (I.e., seconds since the NTP epoch.) the NTP epoch. (I.e., seconds since the NTP epoch.)
ENC_TIME_RFC_3971 - 8 bytes, representing a count of 1/64ths of a ENC_TIME_RFC_3971 - 8 bytes, representing a count of 1/64ths of a
second since the UN*X epoch; see section 5.3.1 "Timestamp Option" second since the UN*X epoch; see section 5.3.1 "Timestamp Option"
in RFC 3971. in RFC 3971.
ENC_TIME_MSEC_NTP - 4-8 bytes, representing a count of milliseconds since ENC_TIME_MSEC_NTP - 4-8 bytes, representing a count of milliseconds since
the NTP epoch. (I.e., milliseconds since the NTP epoch.) the NTP epoch. (I.e., milliseconds since the NTP epoch.)
For FT_RELATIVE_TIME fields, the encoding specifies the form in which For FT_RELATIVE_TIME fields, the encoding specifies the form in which
the time stamp is specified, as well as its byte order. The time stamp the time stamp is specified, as well as its byte order. The time stamp
encodings that are currently supported are: encodings that are currently supported are:
ENC_TIME_SECS_NSECS - 8, 12, or 16 bytes. For 8 bytes, the first 4 ENC_TIME_SECS_NSECS - 8, 12, or 16 bytes. For 8 bytes, the first 4
bytes are seconds and the next 4 bytes are nanoseconds; for 12 bytes are seconds and the next 4 bytes are nanoseconds; for 12
bytes, the first 8 bytes are seconds and the next 4 bytes are bytes, the first 8 bytes are seconds and the next 4 bytes are
nanoseconds; for 16 bytes, the first 8 bytes are seconds and nanoseconds; for 16 bytes, the first 8 bytes are seconds and
@ -1791,9 +1791,9 @@ For other types, there is no support for proto_tree_add_item().
Now that definitions of fields have detailed information about bitfield Now that definitions of fields have detailed information about bitfield
fields, you can use proto_tree_add_item() with no extra processing to fields, you can use proto_tree_add_item() with no extra processing to
add bitfield values to your tree. Here's an example. Take the Format add bitfield values to your tree. Here's an example. Take the Format
Identifier (FID) field in the Transmission Header (TH) portion of the SNA Identifier (FID) field in the Transmission Header (TH) portion of the SNA
protocol. The FID is the high nibble of the first byte of the TH. The protocol. The FID is the high nibble of the first byte of the TH. The
FID would be registered like this: FID would be registered like this:
name = "Format Identifier" name = "Format Identifier"
@ -1814,7 +1814,7 @@ The code to add the FID to the tree would be;
The definition of the field already has the information about bitmasking The definition of the field already has the information about bitmasking
and bitshifting, so it does the work of masking and shifting for us! and bitshifting, so it does the work of masking and shifting for us!
This also means that you no longer have to create value_string structs This also means that you no longer have to create value_string structs
with the values bitshifted. The value_string for FID looks like this, with the values bitshifted. The value_string for FID looks like this,
even though the FID value is actually contained in the high nibble. even though the FID value is actually contained in the high nibble.
(You'd expect the values to be 0x0, 0x10, 0x20, etc.) (You'd expect the values to be 0x0, 0x10, 0x20, etc.)
@ -1850,7 +1850,7 @@ back (to avoid doing tvb_get_...), and/or wish to have the value be decoded
from the tvbuff in a string-encoded format. from the tvbuff in a string-encoded format.
The item added to the GUI tree will contain the name (as passed in the The item added to the GUI tree will contain the name (as passed in the
proto_register_*() function) and a value. The value will be fetched proto_register_*() function) and a value. The value will be fetched
from the tvbuff, based on the type of the XXX name and the encoding of from the tvbuff, based on the type of the XXX name and the encoding of
the value as specified by the "encoding" argument. the value as specified by the "encoding" argument.
@ -1864,7 +1864,7 @@ encoding, this means that a failure to decode the hex value from the string
results in an expert info error being added to the tree. results in an expert info error being added to the tree.
For string-decoding, the passed-in encoding argument needs to specify the For string-decoding, the passed-in encoding argument needs to specify the
string encoding (e.g., ENC_ASCII, ENC_UTF_8) as well as the format. For string encoding (e.g., ENC_ASCII, ENC_UTF_8) as well as the format. For
some XXX types, the format is constrained - for example for the encoding format some XXX types, the format is constrained - for example for the encoding format
for proto_tree_add_time_item() can only be one of the ENC_ISO_8601_* ones for proto_tree_add_time_item() can only be one of the ENC_ISO_8601_* ones
or ENC_RFC_822 or ENC_RFC_1123. For proto_tree_add_bytes_item() it can only or ENC_RFC_822 or ENC_RFC_1123. For proto_tree_add_bytes_item() it can only
@ -1874,7 +1874,7 @@ proto_tree_add_protocol_format()
-------------------------------- --------------------------------
proto_tree_add_protocol_format is used to add the top-level item for the proto_tree_add_protocol_format is used to add the top-level item for the
protocol when the dissector routine wants complete control over how the protocol when the dissector routine wants complete control over how the
field and value will be represented on the GUI tree. The ID value for field and value will be represented on the GUI tree. The ID value for
the protocol is passed in as the "id" argument; the rest of the the protocol is passed in as the "id" argument; the rest of the
arguments are a "printf"-style format and any arguments for that format. arguments are a "printf"-style format and any arguments for that format.
The caller must include the name of the protocol in the format; it is The caller must include the name of the protocol in the format; it is
@ -1935,7 +1935,7 @@ For proto_tree_add_time(), the 'value_ptr' argument is a pointer to an
"nstime_t", which is a structure containing the time to be added; it has "nstime_t", which is a structure containing the time to be added; it has
'secs' and 'nsecs' members, giving the integral part and the fractional 'secs' and 'nsecs' members, giving the integral part and the fractional
part of a time in units of seconds, with 'nsecs' being the number of part of a time in units of seconds, with 'nsecs' being the number of
nanoseconds. For absolute times, "secs" is a UNIX-style seconds since nanoseconds. For absolute times, "secs" is a UNIX-style seconds since
January 1, 1970, 00:00:00 GMT value. January 1, 1970, 00:00:00 GMT value.
For proto_tree_add_ipxnet(), the 'value' argument is a 32-bit IPX For proto_tree_add_ipxnet(), the 'value' argument is a 32-bit IPX
@ -1965,14 +1965,14 @@ For proto_tree_add_double(), the 'value' argument is a 'double' in the
host's floating-point format. host's floating-point format.
For proto_tree_add_uint(), the 'value' argument is a 32-bit unsigned For proto_tree_add_uint(), the 'value' argument is a 32-bit unsigned
integer value, in host byte order. (This routine cannot be used to add integer value, in host byte order. (This routine cannot be used to add
64-bit integers.) 64-bit integers.)
For proto_tree_add_uint64(), the 'value' argument is a 64-bit unsigned For proto_tree_add_uint64(), the 'value' argument is a 64-bit unsigned
integer value, in host byte order. integer value, in host byte order.
For proto_tree_add_int(), the 'value' argument is a 32-bit signed For proto_tree_add_int(), the 'value' argument is a 32-bit signed
integer value, in host byte order. (This routine cannot be used to add integer value, in host byte order. (This routine cannot be used to add
64-bit integers.) 64-bit integers.)
For proto_tree_add_int64(), the 'value' argument is a 64-bit signed For proto_tree_add_int64(), the 'value' argument is a 64-bit signed
@ -2007,10 +2007,10 @@ proto_tree_add_eui64_format()
---------------------------- ----------------------------
These routines are used to add items to the protocol tree when the These routines are used to add items to the protocol tree when the
dissector routine wants complete control over how the field and value dissector routine wants complete control over how the field and value
will be represented on the GUI tree. The argument giving the value is will be represented on the GUI tree. The argument giving the value is
the same as the corresponding proto_tree_add_XXX() function; the rest of the same as the corresponding proto_tree_add_XXX() function; the rest of
the arguments are a "printf"-style format and any arguments for that the arguments are a "printf"-style format and any arguments for that
format. The caller must include the name of the field in the format; it format. The caller must include the name of the field in the format; it
is not added automatically as in the proto_tree_add_XXX() functions. is not added automatically as in the proto_tree_add_XXX() functions.
proto_tree_add_bytes_format_value() proto_tree_add_bytes_format_value()
@ -2034,7 +2034,7 @@ proto_tree_add_eui64_format_value()
These routines are used to add items to the protocol tree when the These routines are used to add items to the protocol tree when the
dissector routine wants complete control over how the value will be dissector routine wants complete control over how the value will be
represented on the GUI tree. The argument giving the value is the same represented on the GUI tree. The argument giving the value is the same
as the corresponding proto_tree_add_XXX() function; the rest of the as the corresponding proto_tree_add_XXX() function; the rest of the
arguments are a "printf"-style format and any arguments for that format. arguments are a "printf"-style format and any arguments for that format.
With these routines, unlike the proto_tree_add_XXX_format() routines, With these routines, unlike the proto_tree_add_XXX_format() routines,
@ -2048,23 +2048,23 @@ proto_tree_add_checksum()
---------------------------- ----------------------------
proto_tree_add_checksum is used to add a checksum field. The hf field proto_tree_add_checksum is used to add a checksum field. The hf field
provided must be the correct size of the checksum (FT_UINT, FT_UINT16, provided must be the correct size of the checksum (FT_UINT, FT_UINT16,
FT_UINT32, etc). Additional parameters are there to provide "status" FT_UINT32, etc). Additional parameters are there to provide "status"
and expert info depending on whether the checksum matches the provided and expert info depending on whether the checksum matches the provided
value. The "status" and expert info can be used in cases except value. The "status" and expert info can be used in cases except
where PROTO_CHECKSUM_NO_FLAGS is used. where PROTO_CHECKSUM_NO_FLAGS is used.
proto_tree_add_subtree() proto_tree_add_subtree()
--------------------- ---------------------
proto_tree_add_subtree() is used to add a label to the GUI tree and create proto_tree_add_subtree() is used to add a label to the GUI tree and create
a subtree for other fields. It will contain no value, so it is not searchable a subtree for other fields. It will contain no value, so it is not searchable
in the display filter process. in the display filter process.
This should only be used for items with subtrees, which may not This should only be used for items with subtrees, which may not
have values themselves - the items in the subtree are the ones with values. have values themselves - the items in the subtree are the ones with values.
For a subtree, the label on the subtree might reflect some of the items For a subtree, the label on the subtree might reflect some of the items
in the subtree. This means the label can't be set until at least some in the subtree. This means the label can't be set until at least some
of the items in the subtree have been dissected. To do this, use of the items in the subtree have been dissected. To do this, use
'proto_item_set_text()' or 'proto_item_append_text()': 'proto_item_set_text()' or 'proto_item_append_text()':
void void
@ -2096,7 +2096,7 @@ available without dissecting any of the data in the subtree.
Note that an exception might be thrown when trying to extract the values of Note that an exception might be thrown when trying to extract the values of
the items used to set the label, if not all the bytes of the item are the items used to set the label, if not all the bytes of the item are
available. Thus, one should create the item with text that is as available. Thus, one should create the item with text that is as
meaningful as possible, and set it or append additional information to meaningful as possible, and set it or append additional information to
it as the values needed to supply that information are extracted. it as the values needed to supply that information are extracted.
@ -2122,7 +2122,7 @@ Works in the same way but also returns the value of the read bits.
proto_tree_add_split_bits_item_ret_val() proto_tree_add_split_bits_item_ret_val()
----------------------------------- -----------------------------------
Similar, but is used for items that are made of 2 or more smaller sets of bits (crumbs) Similar, but is used for items that are made of 2 or more smaller sets of bits (crumbs)
which are not contiguous, but are concatenated to form the actual value. The size of which are not contiguous, but are concatenated to form the actual value. The size of
the crumbs and the order of assembly are specified in an array of crumb_spec structures. the crumbs and the order of assembly are specified in an array of crumb_spec structures.
proto_tree_add_split_bits_crumb() proto_tree_add_split_bits_crumb()
@ -2151,7 +2151,7 @@ the individual subfields of the bitmask. These fields must either be integers
Each of the entries in 'fields' will be dissected as an item under the Each of the entries in 'fields' will be dissected as an item under the
'header' expansion and also IF the field is a boolean and IF it is set to 1, 'header' expansion and also IF the field is a boolean and IF it is set to 1,
then the name of that boolean field will be printed on the 'header' expansion then the name of that boolean field will be printed on the 'header' expansion
line. For integer type subfields that have a value_string defined, the line. For integer type subfields that have a value_string defined, the
matched string from that value_string will be printed on the expansion line matched string from that value_string will be printed on the expansion line
as well. as well.
@ -2259,7 +2259,7 @@ to the tree, from being visible in the displayed tree.
NOTE that creating hidden fields is actually quite a bad idea from a UI design NOTE that creating hidden fields is actually quite a bad idea from a UI design
perspective because the user (someone who did not write nor has ever seen the perspective because the user (someone who did not write nor has ever seen the
code) has no way of knowing that hidden fields are there to be filtered on code) has no way of knowing that hidden fields are there to be filtered on
thus defeating the whole purpose of putting them there. A Better Way might thus defeating the whole purpose of putting them there. A Better Way might
be to add the fields (that might otherwise be hidden) to a subtree where they be to add the fields (that might otherwise be hidden) to a subtree where they
won't be seen unless the user opens the subtree--but they can be found if the won't be seen unless the user opens the subtree--but they can be found if the
user wants. user wants.
@ -2267,8 +2267,8 @@ user wants.
One use for hidden fields (which would be better implemented using visible One use for hidden fields (which would be better implemented using visible
fields in a subtree) follows: The caller may want a value to be fields in a subtree) follows: The caller may want a value to be
included in a tree so that the packet can be filtered on this field, but included in a tree so that the packet can be filtered on this field, but
the representation of that field in the tree is not appropriate. An the representation of that field in the tree is not appropriate. An
example is the token-ring routing information field (RIF). The best way example is the token-ring routing information field (RIF). The best way
to show the RIF in a GUI is by a sequence of ring and bridge numbers. to show the RIF in a GUI is by a sequence of ring and bridge numbers.
Rings are 3-digit hex numbers, and bridges are single hex digits: Rings are 3-digit hex numbers, and bridges are single hex digits:
@ -2416,7 +2416,7 @@ Where:
next_tvb is the new TVBUFF_SUBSET. next_tvb is the new TVBUFF_SUBSET.
offset is the byte offset of 'tvb' at which the new tvbuff offset is the byte offset of 'tvb' at which the new tvbuff
should start. The first byte is the 0th byte. should start. The first byte is the 0th byte.
To create a new TVBUFF_SUBSET that begins at a specified offset in a To create a new TVBUFF_SUBSET that begins at a specified offset in a
parent tvbuff, with a specified number of bytes in the payload, the parent tvbuff, with a specified number of bytes in the payload, the
@ -2431,7 +2431,7 @@ Where:
next_tvb is the new TVBUFF_SUBSET. next_tvb is the new TVBUFF_SUBSET.
offset is the byte offset of 'tvb' at which the new tvbuff offset is the byte offset of 'tvb' at which the new tvbuff
should start. The first byte is the 0th byte. should start. The first byte is the 0th byte.
reported_length is the number of bytes that the current protocol reported_length is the number of bytes that the current protocol
says should be in the payload. says should be in the payload.
@ -2450,7 +2450,7 @@ Where:
next_tvb is the new TVBUFF_SUBSET. next_tvb is the new TVBUFF_SUBSET.
offset is the byte offset of 'tvb' at which the new tvbuff offset is the byte offset of 'tvb' at which the new tvbuff
should start. The first byte is the 0th byte. should start. The first byte is the 0th byte.
length is the number of bytes in the new TVBUFF_SUBSET. A length length is the number of bytes in the new TVBUFF_SUBSET. A length
argument of -1 says to use as many bytes as are available in argument of -1 says to use as many bytes as are available in
@ -2461,7 +2461,7 @@ Where:
the protocol doesn't say anything about the size of its payload. the protocol doesn't say anything about the size of its payload.
To call a dissector you need to get the handle of the dissector using To call a dissector you need to get the handle of the dissector using
find_dissector(), passing it the string name of the dissector. The setting find_dissector(), passing it the string name of the dissector. The setting
of the handle is usually done once at startup during the proto_reg_handoff of the handle is usually done once at startup during the proto_reg_handoff
function within the calling dissector. function within the calling dissector.
@ -2469,7 +2469,7 @@ function within the calling dissector.
Another way to call a subdissector is to setup a dissector table. A dissector Another way to call a subdissector is to setup a dissector table. A dissector
table is a list of subdissectors grouped by a common identifier (integer or table is a list of subdissectors grouped by a common identifier (integer or
string) in a dissector. Subdissectors will register themselves with the dissector string) in a dissector. Subdissectors will register themselves with the dissector
table using their unique identifier using one of the following APIs: table using their unique identifier using one of the following APIs:
void dissector_add_uint(const char *abbrev, const guint32 pattern, void dissector_add_uint(const char *abbrev, const guint32 pattern,
@ -2540,7 +2540,7 @@ section of epan/dissectors/CMakeLists.txt
./tools/cppcheck/cppcheck.sh <source-filename(s)> ./tools/cppcheck/cppcheck.sh <source-filename(s)>
- TEST YOUR DISSECTOR BEFORE SUBMITTING IT. - TEST YOUR DISSECTOR BEFORE SUBMITTING IT.
Use fuzz-test.sh and/or randpkt against your dissector. These are Use fuzz-test.sh and/or randpkt against your dissector. These are
described at <https://wiki.wireshark.org/FuzzTesting>. described at <https://wiki.wireshark.org/FuzzTesting>.
- Subscribe to <mailto:wireshark-dev[AT]wireshark.org> by sending an email to - Subscribe to <mailto:wireshark-dev[AT]wireshark.org> by sending an email to
@ -2555,7 +2555,7 @@ section of epan/dissectors/CMakeLists.txt
should be a summary of the changes followed by an empty line and a more should be a summary of the changes followed by an empty line and a more
verbose description. verbose description.
- 'git push origin HEAD:refs/for/master' to push the changes to Gerrit. (If - 'git push origin HEAD:refs/for/master' to push the changes to Gerrit. (If
you previously ran 'git config --add remote.origin.push HEAD:refs/for/master' you previously ran 'git config --add remote.origin.push HEAD:refs/for/master'
then only 'git push' is needed.) then only 'git push' is needed.)
@ -2565,13 +2565,13 @@ section of epan/dissectors/CMakeLists.txt
and <https://wiki.wireshark.org/ProtocolReference> and <https://wiki.wireshark.org/ProtocolReference>
- If possible, add sample capture files to the sample captures page at - If possible, add sample capture files to the sample captures page at
<https://wiki.wireshark.org/SampleCaptures>. These files are used by <https://wiki.wireshark.org/SampleCaptures>. These files are used by
the automated build system for fuzz testing. the automated build system for fuzz testing.
- If you don't think the wiki is the right place for your sample capture, - If you don't think the wiki is the right place for your sample capture,
submit a bug report to the Wireshark bug database, found at submit a bug report to the Wireshark bug database, found at
<https://bugs.wireshark.org>, qualified as an enhancement and attach your <https://bugs.wireshark.org>, qualified as an enhancement and attach your
sample capture there. Normally a new dissector won't be accepted without sample capture there. Normally a new dissector won't be accepted without
a sample capture! If you open a bug be sure to cross-link your Gerrit a sample capture! If you open a bug be sure to cross-link your Gerrit
change and bug. change and bug.
@ -2585,8 +2585,8 @@ it is wise to check the relevant header and source files for additional details.
2.2 Following "conversations". 2.2 Following "conversations".
In wireshark a conversation is defined as a series of data packets between two In wireshark a conversation is defined as a series of data packets between two
address:port combinations. A conversation is not sensitive to the direction of address:port combinations. A conversation is not sensitive to the direction of
the packet. The same conversation will be returned for a packet bound from the packet. The same conversation will be returned for a packet bound from
ServerA:1000 to ClientA:2000 and the packet from ClientA:2000 to ServerA:1000. ServerA:1000 to ClientA:2000 and the packet from ClientA:2000 to ServerA:1000.
2.2.1 Conversation Routines 2.2.1 Conversation Routines
@ -2599,12 +2599,12 @@ conversation_delete_proto_data, and conversation_set_dissector.
2.2.1.1 The conversation_init function. 2.2.1.1 The conversation_init function.
This is an internal routine for the conversation code. As such you This is an internal routine for the conversation code. As such you
will not have to call this routine. Just be aware that this routine is will not have to call this routine. Just be aware that this routine is
called at the start of each capture and before the packets are filtered called at the start of each capture and before the packets are filtered
with a display filter. The routine will destroy all stored with a display filter. The routine will destroy all stored
conversations. This routine does NOT clean up any data pointers that are conversations. This routine does NOT clean up any data pointers that are
passed in the conversation_add_proto_data 'data' variable. You are passed in the conversation_add_proto_data 'data' variable. You are
responsible for this clean up if you pass a malloc'ed pointer responsible for this clean up if you pass a malloc'ed pointer
in this variable. in this variable.
@ -2614,13 +2614,13 @@ See item 2.2.1.5 for more information about use of the 'data' pointer.
2.2.1.2 The conversation_new function. 2.2.1.2 The conversation_new function.
This routine will create a new conversation based upon two address/port This routine will create a new conversation based upon two address/port
pairs. If you want to associate with the conversation a pointer to a pairs. If you want to associate with the conversation a pointer to a
private data structure you must use the conversation_add_proto_data private data structure you must use the conversation_add_proto_data
function. The ptype variable is used to differentiate between function. The ptype variable is used to differentiate between
conversations over different protocols, i.e. TCP and UDP. The options conversations over different protocols, i.e. TCP and UDP. The options
variable is used to define a conversation that will accept any destination variable is used to define a conversation that will accept any destination
address and/or port. Set options = 0 if the destination port and address address and/or port. Set options = 0 if the destination port and address
are know when conversation_new is called. See section 2.4 for more are know when conversation_new is called. See section 2.4 for more
information on usage of the options parameter. information on usage of the options parameter.
The conversation_new prototype: The conversation_new prototype:
@ -2642,7 +2642,7 @@ distinguish multiple conversations with the same addr1/port1 and addr2/port2
pair that occur within the same capture session. pair that occur within the same capture session.
"addr1" and "port1" are the first address/port pair; "addr2" and "port2" "addr1" and "port1" are the first address/port pair; "addr2" and "port2"
are the second address/port pair. A conversation doesn't have source are the second address/port pair. A conversation doesn't have source
and destination address/port pairs - packets in a conversation go in and destination address/port pairs - packets in a conversation go in
both directions - so "addr1"/"port1" may be the source or destination both directions - so "addr1"/"port1" may be the source or destination
address/port pair; "addr2"/"port2" would be the other pair. address/port pair; "addr2"/"port2" would be the other pair.
@ -2652,14 +2652,14 @@ conversation lookup will match only the "addr1" address; if NO_PORT2 is
specified, the conversation is set up so that a conversation lookup will specified, the conversation is set up so that a conversation lookup will
match only the "port1" port; if both are specified, i.e. match only the "port1" port; if both are specified, i.e.
NO_ADDR2|NO_PORT2, the conversation is set up so that the lookup will NO_ADDR2|NO_PORT2, the conversation is set up so that the lookup will
match only the "addr1"/"port1" address/port pair. This can be used if a match only the "addr1"/"port1" address/port pair. This can be used if a
packet indicates that, later in the capture, a conversation will be packet indicates that, later in the capture, a conversation will be
created using certain addresses and ports, in the case where the packet created using certain addresses and ports, in the case where the packet
doesn't specify the addresses and ports of both sides. doesn't specify the addresses and ports of both sides.
2.2.1.3 The find_conversation function. 2.2.1.3 The find_conversation function.
Call this routine to look up a conversation. If no conversation is found, Call this routine to look up a conversation. If no conversation is found,
the routine will return a NULL value. the routine will return a NULL value.
The find_conversation prototype: The find_conversation prototype:
@ -2689,10 +2689,10 @@ returned. If (frame_num >= 50 && frame_num < 100), conversation B is returned.
If (frame_num >= 100) conversation C is returned. If (frame_num >= 100) conversation C is returned.
"addr_a" and "port_a" are the first address/port pair; "addr_b" and "addr_a" and "port_a" are the first address/port pair; "addr_b" and
"port_b" are the second address/port pair. Again, as a conversation "port_b" are the second address/port pair. Again, as a conversation
doesn't have source and destination address/port pairs, so doesn't have source and destination address/port pairs, so
"addr_a"/"port_a" may be the source or destination address/port pair; "addr_a"/"port_a" may be the source or destination address/port pair;
"addr_b"/"port_b" would be the other pair. The search will match the "addr_b"/"port_b" would be the other pair. The search will match the
"a" address/port pair against both the "1" and "2" address/port pairs, "a" address/port pair against both the "1" and "2" address/port pairs,
and match the "b" address/port pair against both the "2" and "1" and match the "b" address/port pair against both the "2" and "1"
address/port pairs; you don't have to worry about which side the "a" or address/port pairs; you don't have to worry about which side the "a" or
@ -2701,7 +2701,7 @@ address/port pairs; you don't have to worry about which side the "a" or
If the NO_ADDR_B flag was specified to "find_conversation()", the If the NO_ADDR_B flag was specified to "find_conversation()", the
"addr_b" address will be treated as matching any "wildcarded" address; "addr_b" address will be treated as matching any "wildcarded" address;
if the NO_PORT_B flag was specified, the "port_b" port will be treated if the NO_PORT_B flag was specified, the "port_b" port will be treated
as matching any "wildcarded" port. If both flags are specified, i.e. as matching any "wildcarded" port. If both flags are specified, i.e.
NO_ADDR_B|NO_PORT_B, the "addr_b" address will be treated as matching NO_ADDR_B|NO_PORT_B, the "addr_b" address will be treated as matching
any "wildcarded" address and the "port_b" port will be treated as any "wildcarded" address and the "port_b" port will be treated as
matching any "wildcarded" port. matching any "wildcarded" port.
@ -2754,11 +2754,11 @@ Where:
int proto = registered protocol number int proto = registered protocol number
void *data = dissector data structure void *data = dissector data structure
"conversation" is the value returned by conversation_new. "proto" is a "conversation" is the value returned by conversation_new. "proto" is a
unique protocol number created with proto_register_protocol. Protocols unique protocol number created with proto_register_protocol. Protocols
are typically registered in the proto_register_XXXX section of your are typically registered in the proto_register_XXXX section of your
dissector. "data" is a pointer to the data you wish to associate with the dissector. "data" is a pointer to the data you wish to associate with the
conversation. "data" usually points to "wmem_alloc'd" memory; the conversation. "data" usually points to "wmem_alloc'd" memory; the
memory will be automatically freed each time a new dissection begins memory will be automatically freed each time a new dissection begins
and thus need not be managed (freed) by the dissector. and thus need not be managed (freed) by the dissector.
Using the protocol number allows several dissectors to Using the protocol number allows several dissectors to
@ -2778,17 +2778,17 @@ Where:
conversation_t *conv = the conversation in question conversation_t *conv = the conversation in question
int proto = registered protocol number int proto = registered protocol number
"conversation" is the conversation created with conversation_new. "proto" "conversation" is the conversation created with conversation_new. "proto"
is a unique protocol number created with proto_register_protocol, is a unique protocol number created with proto_register_protocol,
typically in the proto_register_XXXX portion of a dissector. The function typically in the proto_register_XXXX portion of a dissector. The function
returns a pointer to the data requested, or NULL if no data was found. returns a pointer to the data requested, or NULL if no data was found.
2.2.1.8 The conversation_delete_proto_data function. 2.2.1.8 The conversation_delete_proto_data function.
After you are finished with a conversation, you can remove your association After you are finished with a conversation, you can remove your association
with this function. Please note that ONLY the conversation entry is with this function. Please note that ONLY the conversation entry is
removed. If you have allocated any memory for your data (other than with wmem_alloc), removed. If you have allocated any memory for your data (other than with wmem_alloc),
you must free it as well. you must free it as well.
The conversation_delete_proto_data prototype: The conversation_delete_proto_data prototype:
@ -2799,7 +2799,7 @@ Where:
conversation_t *conv = the conversation in question conversation_t *conv = the conversation in question
int proto = registered protocol number int proto = registered protocol number
"conversation" is the conversation created with conversation_new. "proto" "conversation" is the conversation created with conversation_new. "proto"
is a unique protocol number created with proto_register_protocol, is a unique protocol number created with proto_register_protocol,
typically in the proto_register_XXXX portion of a dissector. typically in the proto_register_XXXX portion of a dissector.
@ -2867,7 +2867,7 @@ the tcp-dissector.
2.2.3 The example conversation code using wmem_file_scope memory. 2.2.3 The example conversation code using wmem_file_scope memory.
For a conversation between two IP addresses and ports you can use this as an For a conversation between two IP addresses and ports you can use this as an
example. This example uses wmem_alloc() with wmem_file_scope() to allocate example. This example uses wmem_alloc() with wmem_file_scope() to allocate
memory and stores the data pointer in the conversation 'data' variable. memory and stores the data pointer in the conversation 'data' variable.
/************************ Global values ************************/ /************************ Global values ************************/
@ -2945,15 +2945,15 @@ that starts at the specific frame number.
2.2.5 The example conversation code using conversation index field. 2.2.5 The example conversation code using conversation index field.
Sometimes the conversation isn't enough to define a unique data storage Sometimes the conversation isn't enough to define a unique data storage
value for the network traffic. For example if you are storing information value for the network traffic. For example if you are storing information
about requests carried in a conversation, the request may have an about requests carried in a conversation, the request may have an
identifier that is used to define the request. In this case the identifier that is used to define the request. In this case the
conversation and the identifier are required to find the data storage conversation and the identifier are required to find the data storage
pointer. You can use the conversation data structure index value to pointer. You can use the conversation data structure index value to
uniquely define the conversation. uniquely define the conversation.
See packet-afs.c for an example of how to use the conversation index. In See packet-afs.c for an example of how to use the conversation index. In
this dissector multiple requests are sent in the same conversation. To store this dissector multiple requests are sent in the same conversation. To store
information for each request the dissector has an internal hash table based information for each request the dissector has an internal hash table based
upon the conversation index and values inside the request packets. upon the conversation index and values inside the request packets.
@ -2995,13 +2995,13 @@ upon the conversation index and values inside the request packets.
NOTE: This sections assumes that all information is available to NOTE: This sections assumes that all information is available to
create a complete conversation, source port/address and create a complete conversation, source port/address and
destination port/address. If either the destination port or destination port/address. If either the destination port or
address is known, see section 2.4 Dynamic server port dissector address is known, see section 2.4 Dynamic server port dissector
registration. registration.
For protocols that negotiate a secondary port connection, for example For protocols that negotiate a secondary port connection, for example
packet-msproxy.c, a conversation can install a dissector to handle packet-msproxy.c, a conversation can install a dissector to handle
the secondary protocol dissection. After the conversation is created the secondary protocol dissection. After the conversation is created
for the negotiated ports use the conversation_set_dissector to define for the negotiated ports use the conversation_set_dissector to define
the dissection routine. the dissection routine.
Before we create these conversations or assign a dissector to them we should Before we create these conversations or assign a dissector to them we should
@ -3079,12 +3079,12 @@ proto_register_PROTOABBREV(void)
NOTE: While this example used both NO_ADDR2 and NO_PORT2 to create a NOTE: While this example used both NO_ADDR2 and NO_PORT2 to create a
conversation with only one port and address set, this isn't a conversation with only one port and address set, this isn't a
requirement. Either the second port or the second address can be set requirement. Either the second port or the second address can be set
when the conversation is created. when the conversation is created.
For protocols that define a server address and port for a secondary For protocols that define a server address and port for a secondary
protocol, a conversation can be used to link a protocol dissector to protocol, a conversation can be used to link a protocol dissector to
the server port and address. The key is to create the new the server port and address. The key is to create the new
conversation with the second address and port set to the "accept conversation with the second address and port set to the "accept
any" values. any" values.
@ -3108,8 +3108,8 @@ conversation_set_port2( conversation_t *conv, guint32 port);
conversation_set_addr2( conversation_t *conv, address addr); conversation_set_addr2( conversation_t *conv, address addr);
These routines will change the second address or port for the These routines will change the second address or port for the
conversation. So, the server port conversation will be converted into a conversation. So, the server port conversation will be converted into a
more complete conversation definition. Don't use these routines if you more complete conversation definition. Don't use these routines if you
want to create a conversation between the server and client and retain the want to create a conversation between the server and client and retain the
server port definition, you must create a new conversation. server port definition, you must create a new conversation.
@ -3155,8 +3155,8 @@ static dissector_handle_t sub_dissector_handle;
2.5 Per-packet information. 2.5 Per-packet information.
Information can be stored for each data packet that is processed by the Information can be stored for each data packet that is processed by the
dissector. The information is added with the p_add_proto_data function and dissector. The information is added with the p_add_proto_data function and
retrieved with the p_get_proto_data function. The data pointers passed into retrieved with the p_get_proto_data function. The data pointers passed into
the p_add_proto_data are not managed by the proto_data routines, however the the p_add_proto_data are not managed by the proto_data routines, however the
data pointer memory scope must match that of the scope parameter. data pointer memory scope must match that of the scope parameter.
The two most common use cases for p_add_proto_data/p_get_proto_data are for The two most common use cases for p_add_proto_data/p_get_proto_data are for
@ -3173,7 +3173,7 @@ p_get_proto_data(wmem_allocator_t *scope, packet_info *pinfo, int proto, guint32
Where: Where:
scope - Lifetime of the data to be stored, typically wmem_file_scope() scope - Lifetime of the data to be stored, typically wmem_file_scope()
or pinfo->pool (packet scope). Must match scope of data or pinfo->pool (packet scope). Must match scope of data
allocated. allocated.
pinfo - The packet info pointer. pinfo - The packet info pointer.
proto - Protocol id returned by the proto_register_protocol call proto - Protocol id returned by the proto_register_protocol call
@ -3250,15 +3250,15 @@ Where: module - Returned by the prefs_register_protocol routine
description - Comments added to the preference file above the description - Comments added to the preference file above the
preference value and shown as tooltip in the GUI, or NULL preference value and shown as tooltip in the GUI, or NULL
var - pointer to the storage location that is updated when the var - pointer to the storage location that is updated when the
field is changed in the preference dialog box. Note that field is changed in the preference dialog box. Note that
with string preferences the given pointer is overwritten with string preferences the given pointer is overwritten
with a pointer to a new copy of the string during the with a pointer to a new copy of the string during the
preference registration. The passed-in string may be preference registration. The passed-in string may be
freed, but you must keep another pointer to the string freed, but you must keep another pointer to the string
in order to free it. in order to free it.
base - Base that the unsigned integer is expected to be in, base - Base that the unsigned integer is expected to be in,
see strtoul(3). see strtoul(3).
enumvals - an array of enum_val_t structures. This must be enumvals - an array of enum_val_t structures. This must be
NULL-terminated; the members of that structure are: NULL-terminated; the members of that structure are:
a short name, to be used with the "-o" flag - it a short name, to be used with the "-o" flag - it
@ -3316,17 +3316,17 @@ a preference obsolete is to register it as such:
2.7 Reassembly/desegmentation for protocols running atop TCP. 2.7 Reassembly/desegmentation for protocols running atop TCP.
There are two main ways of reassembling a Protocol Data Unit (PDU) which There are two main ways of reassembling a Protocol Data Unit (PDU) which
spans across multiple TCP segments. The first approach is simpler, but spans across multiple TCP segments. The first approach is simpler, but
assumes you are running atop of TCP when this occurs (but your dissector assumes you are running atop of TCP when this occurs (but your dissector
might run atop of UDP, too, for example), and that your PDUs consist of a might run atop of UDP, too, for example), and that your PDUs consist of a
fixed amount of data that includes enough information to determine the PDU fixed amount of data that includes enough information to determine the PDU
length, possibly followed by additional data. The second method is more length, possibly followed by additional data. The second method is more
generic but requires more code and is less efficient. generic but requires more code and is less efficient.
2.7.1 Using tcp_dissect_pdus(). 2.7.1 Using tcp_dissect_pdus().
For the first method, you register two different dissection methods, one For the first method, you register two different dissection methods, one
for the TCP case, and one for the other cases. It is a good idea to for the TCP case, and one for the other cases. It is a good idea to
also have a dissect_PROTO_common function which will parse the generic also have a dissect_PROTO_common function which will parse the generic
content that you can find in all PDUs which is called from content that you can find in all PDUs which is called from
dissect_PROTO_tcp when the reassembly is complete and from dissect_PROTO_tcp when the reassembly is complete and from
@ -3410,8 +3410,8 @@ If the dissector discovers that the end of the tvbuff does /not/ coincide with
the end of a PDU, (ie, there is half of a PDU at the end of the tvbuff), it can the end of a PDU, (ie, there is half of a PDU at the end of the tvbuff), it can
indicate this to the parent dissector, by updating the pinfo struct. The indicate this to the parent dissector, by updating the pinfo struct. The
desegment_offset field is the offset in the tvbuff at which the dissector will desegment_offset field is the offset in the tvbuff at which the dissector will
continue processing when next called. The desegment_len field should contain continue processing when next called. The desegment_len field should contain
the estimated number of additional bytes required for completing the PDU. Next the estimated number of additional bytes required for completing the PDU. Next
time your dissect_PROTO is called, it will be passed a tvbuff composed of the time your dissect_PROTO is called, it will be passed a tvbuff composed of the
end of the data from the previous tvbuff together with desegment_len more bytes. end of the data from the previous tvbuff together with desegment_len more bytes.
@ -3479,7 +3479,7 @@ loop.
As noted in section 2.7.1, TCP has an API to dissect its PDU that can handle As noted in section 2.7.1, TCP has an API to dissect its PDU that can handle
a PDU spread across multiple packets or multiple PDUs spread across a single a PDU spread across multiple packets or multiple PDUs spread across a single
packet. This section describes a similar mechanism for UDP, but is only packet. This section describes a similar mechanism for UDP, but is only
applicable for one or more PDUs in a single packet. If a protocol runs on top applicable for one or more PDUs in a single packet. If a protocol runs on top
of TCP as well as UDP, a common PDU dissection function can be created for both. of TCP as well as UDP, a common PDU dissection function can be created for both.
@ -3563,7 +3563,7 @@ The arguments to udp_dissect_pdus are:
2.9 PINOs (Protocols in name only) 2.9 PINOs (Protocols in name only)
For the typical dissector there is a 1-1 relationship between it and it's For the typical dissector there is a 1-1 relationship between it and it's
protocol. However, there are times when a protocol needs multiple "names" protocol. However, there are times when a protocol needs multiple "names"
because it has multiple dissection functions going into the same dissector because it has multiple dissection functions going into the same dissector
table. The muliple names removes confusion when picking dissection through table. The muliple names removes confusion when picking dissection through
Decode As functionality. Decode As functionality.
@ -3571,8 +3571,8 @@ Decode As functionality.
Once the "main" protocol name has been created through proto_register_protocol, Once the "main" protocol name has been created through proto_register_protocol,
additional "pinos" can be created with proto_register_protocol_in_name_only. additional "pinos" can be created with proto_register_protocol_in_name_only.
These pinos have all of the naming conventions of a protocol, but are stored These pinos have all of the naming conventions of a protocol, but are stored
separately as to remove confusion from real protocols. "pinos" the main separately as to remove confusion from real protocols. "pinos" the main
protocol's properties for things like enable/disable. i.e. If the "main" protocol's properties for things like enable/disable. i.e. If the "main"
protocol has been disabled, all of its pinos will be disabled as well. protocol has been disabled, all of its pinos will be disabled as well.
Pinos should not have any fields registered with them or heuristic tables Pinos should not have any fields registered with them or heuristic tables
associated with them. associated with them.
@ -3580,8 +3580,8 @@ associated with them.
Another use case for pinos is when a protocol contains a TLV design and it Another use case for pinos is when a protocol contains a TLV design and it
wants to create a dissector table to handle dissection of the "V". Dissector wants to create a dissector table to handle dissection of the "V". Dissector
tables require a "protocol", but the dissection functions for that table tables require a "protocol", but the dissection functions for that table
typically aren't a protocol. In this case proto_register_protocol_in_name_only typically aren't a protocol. In this case proto_register_protocol_in_name_only
creates the necessary placeholder for the dissector table. In addition, because creates the necessary placeholder for the dissector table. In addition, because
a dissector table exists, "V"s of the TLVs can be dissected outside of the a dissector table exists, "V"s of the TLVs can be dissected outside of the
original dissector file. original dissector file.
@ -3606,7 +3606,7 @@ Consider the following example using IP dissection, stolen from packet-ip.c:
register_decode_as(&ip_da); register_decode_as(&ip_da);
ip_da_build_value contains all of the function pointers (typically just 1) that ip_da_build_value contains all of the function pointers (typically just 1) that
can be used to retrieve the value(s) that go into the dissector table. This is can be used to retrieve the value(s) that go into the dissector table. This is
usually data saved by the dissector during packet dissector with an API like usually data saved by the dissector during packet dissector with an API like
p_add_proto_data and retrieved in the "value" function with p_get_proto_data. p_add_proto_data and retrieved in the "value" function with p_get_proto_data.
@ -3617,7 +3617,7 @@ be passed to the dissector table to change the dissection output.
ip_da pulls everything together including the dissector (protocol) name, the ip_da pulls everything together including the dissector (protocol) name, the
"layer type" of the dissector, the dissector table name, the function pointer "layer type" of the dissector, the dissector table name, the function pointer
values as well as handlers for populating, applying and reseting the changes values as well as handlers for populating, applying and reseting the changes
to the dissector table through Decode As GUI functionality. For dissector to the dissector table through Decode As GUI functionality. For dissector
tables that are an integer or string type, the provided "default" handling tables that are an integer or string type, the provided "default" handling
functions shown in the example should suffice. functions shown in the example should suffice.
@ -3778,7 +3778,7 @@ can be passed a null protocol tree pointer, in which case they'll
return a null item pointer, and "proto_item_add_subtree()" returns return a null item pointer, and "proto_item_add_subtree()" returns
a null tree pointer if passed a null item pointer, so, if you're a null tree pointer if passed a null item pointer, so, if you're
careful not to dereference any null tree or item pointers, you can careful not to dereference any null tree or item pointers, you can
accomplish this by doing all the dissection work. This might not accomplish this by doing all the dissection work. This might not
be as efficient as skipping that work if you're not building a be as efficient as skipping that work if you're not building a
protocol tree, but if the code would have a lot of tests whether protocol tree, but if the code would have a lot of tests whether
"tree" is null if you skipped that work, you might still be better "tree" is null if you skipped that work, you might still be better