proto_tree_add_item was valid *before* we short-circuited based on a NULL tree.
This was good in that it removed a common source of really-long-loop bugs. It
was less good in that it cost us about 8% in speed when doing a tree-less
dissection, but we decided the tradeoff was worth it.
After Anders' recent mail to -dev about performance, I started thinking about
how to optimize this. It occurred to me that the vast majority of the logic
involved in the check was dealing with the length value - fetching the actual
length if it was a counted string, calculating the length if it was -1, adding
the length to the offset in a way that was free from overflows, etc.
All of this is (theoretically) unnecessary - simply checking the offset without
worrying about the length will still catch the very-long-loops, since it is the
offset that increases in each iteration, not the length.
All that to justify:
- implement tvb_ensure_offset_exists which throws an exception if the offset is
not within the tvb
- use it instead of all the complicated other logic in the pre-short-circuit
step of proto_tree_add_item and friends
This gives us back about 3/4 of the performance we lost in the original patch.
We're still ~2% slower than without any check, but this is the best I can think
of right now.
svn path=/trunk/; revision=52578
explicit, and frees up the "generic" names (like tvb_memdup) for new signatures
that take the appropriate wmem pool.
Majority of the conversion done with sed.
svn path=/trunk/; revision=52164
haven't reassembled, we're probably moving sequentially through the
packet, which means that we'll run past the end of the fragment rather
than past the end of what would have been the reassembled packet had we
reassembled it.
I.e., there's little reason to care whether we're past the end of the
fragment but not past the end of the packet, or whether we're past the
end of the packet; in either case, we're past the end of the fragment,
and if somebody wants to know whether the packet is malformed by
stopping short of certain fields, they should enable reassembly.
So we get rid of the explicit fragment length in tvbuffs and, instead,
have a "this is a fragment" flag; if that flag is set, we throw
FragmentBoundsError rather than ReportedBoundsError if we run past the
end of the reported data.
(This also means we could flag the tvbuff even if we don't know how
large the reassembled packet will be, e.g. when doing IP reassembly.)
Replace tvb_new_subset_length_fragment() with tvb_new_subset_length()
and a new "set the "this is a fragment flag"" routine.
svn path=/trunk/; revision=48940
first fragment of a non-reassembled packet, and we know the length the
packet would have if it were reassembled, this field holds the length of
the fragment, and the "reported length" field shows the length the
packet would have if it were reassembled, so going past the end of the
fragment but staying within the length of the reassembled packet can be
reported as "dissection would have worked if the packet had been
reassembled" rather than "the packet is too short, so it was probably
malformed".
Add a FragmentBoundsError exception, thrown in the "dissection would
have worked if the packet had been reassembled" case.
Add a new tvb_new_subset_length_fragment() routine to create a new
subset tvb with specified fragment and reported lengths. Use it in the
CLNP dissector.
Add some more sanity checks in the CLNP dissector.
svn path=/trunk/; revision=48917
tvbuff, and a length from that offset, and returns a subset tvbuff
referring to that data (or throws an exception). This does what most if
not all calls to tvb_new_subset() (other than the ones that really
should be calls to tvb_new_subset_remaining()) should be doing, i.e.
setting the reported length of the tvbuff to the specified length and
calculating the appropriate value of the captured length based on that.
We aren't using it yet, but we will....
svn path=/trunk/; revision=47768
tvb_set_subset(); code should use tvb_new_real_data() and various
tvb_new_subset routines. (Neither tvb_new() nor tvb_set_real_data() nor
tvb_set_subset() were exported in libwireshark.def, nor were they used
outside tvbuff.c; tvb_set_real_data() and tvb_set_subset() weren't even
being used *inside* tvbuff.c.)
svn path=/trunk/; revision=47753
routines to create new tvbuffs that do what dissectors need to do, and
those are the only routines that should be used.
svn path=/trunk/; revision=47752
Put the code that's currently common to the ENC_ASCII and ENC_UTF_8
cases in tvb_get_ephemeral_string_enc() into tvb_get_ephemeral_string(),
and call tvb_get_ephemeral_string() in those cases. Skip the
tvb_ensure_bytes_exist() and ensure_contiguous() calls in the ENC_UTF_16
and ENC_UCS_2 cases, as they're unnecessary there.
Update the comment for tvb_get_ephemeral_string_enc().
Make tvb_get_ephemeral_stringz_enc() handle the encodings that
tvb_get_ephemeral_string_enc() does.
svn path=/trunk/; revision=42627
proto_tree_add_item() calls.
Add new "add_packet_field" method to the TreeItem class, taking a
protocol field (*not* a protocol), TvbRange, and encoding value as
arguments.
Add the ENC_ values to init.lua. Make them all hex #defines so
make-init-lua.pl can easily extract them.
Export tvb_unicode_strsize() for use by Lua (and elsewhere as desired).
Note that it handles UTF-16 and UTF-8, and fix the comment to note that
its count of hexadectets *does* include the null terminator (that's what
the code does).
svn path=/trunk/; revision=42621
removes a potential buffer overflow and should fix a bunch of Coverity
errors mentioned in bug 6878.
We might want to do the same for no_of_bits.
svn path=/trunk/; revision=41945
- Essentially no changes from current dissector de facto tvbuff usage;
- Do away with 'usage_counts' and with 'used_in' GSLists;
- Manage tvb chains via a simple doubly linked list.
- API changes:
a. tvb_increment_usage_count() and tvb_decrement_usage_count() no
longer exist;
b. tvb_free_chain() can only be called for the 'top-level' (initial)
tvb of a chain) or for a tvb not in a chain.
c. tvb_free() now just calls tvb_free_chain() [should have no impact
on existing dissectors].
svn path=/trunk/; revision=40264
appropriately; the only valid encoding is big-endian, so we don't
actually do anything different with the argument, so as not to break
code that passed it a gboolean endian flag.
svn path=/trunk/; revision=39237
in README.devloper. Remove g_gnuc.h since it's no longer needed. Remove
tvbuff_init(), tvbuff_cleanup(), reassemble_init(), and
reassemble_cleanup() since they were only used for older GLib versions
which didn't support GSlices. Assume we always support the "matches"
operator.
svn path=/trunk/; revision=37978
make FT_STRING and FT_UINT_STRING handle string encodings.
Get rid of FT_EBCDIC in favor of FT_STRING with ENC_EBCDIC.
Add some URLs for DRDA.
Clean up some stuff in TN3270 and TN5250, including using ENC_ values
for proto_tree_add_item().
svn path=/trunk/; revision=37909
tvb_get_ephemeral_string() but takes an ENC_ value for the character
encoding. Use it in the MQ dissector to fetch strings to put, for
example, into the Info column, so we properly handle EBCDIC strings
there.
svn path=/trunk/; revision=37876
pointer to a NULL-terminated string in the TVB. It is no safer than dissectors
which call tvb_get_strsize() and then tvb_get_ptr() but it makes it clear that
this usage of tvb_get_ptr() is safe.
This function is slightly more efficient than tvb_get_ephemeral_stringz()--but
only as long as we're not using composite TVBs.
svn path=/trunk/; revision=35493
tvb_get_unicode_string()
tvb_get_ephemeral_unicode_string()
These function like their counterparts, tvb_get_string and
tvb_get_epemeral_string, for standard strings.
Also update comment on what the first such function,
tvb_get_ephemeral_unicode_stringz does regarding updating lengthp.
svn path=/trunk/; revision=35344
/*
* Given a tvbuff, an offset into the tvbuff, and a length that starts
* at that offset (which may be -1 for "all the way to the end of the
* tvbuff"), fetch BCD encoded digits from a tvbuff starting from either
* the low or high half byte, formating the digits according to an input digit set,
* if NUll a default digit set of 0-9 returning "?" for overdecadic digits will be used.
* A pointer to the EP allocated string will be returned.
* Note a tvbuff content of 0xf is considered a 'filler' and will end the conversion.
*/
svn path=/trunk/; revision=35286
is a unicode (UTF-16) version of tvb_get_ephemeral_stringz(). It scans
a tvbuff for a UTF-16 string and converts it to UTF-8 upon return.
svn path=/trunk/; revision=35253
