Thanks Chris,
If I remember correctly, apart from an annoying, misleading "malformed
packet" error, I eventually managed to dump all of the block IDs (1-4)
using either :
/* Start counting from 13 */
for (rwe_pos = 13; rwe_pos < tvb_get_guint8(tvb, 13); rwe_pos+=2) {
proto_tree_add_item(felica_tree, hf_felica_block_nbr, tvb,
rwe_pos+1, 1, ENC_BIG_ENDIAN);
}
or
/* Start counting from 13 */
for (rwe_pos = 13; rwe_pos < tvb_get_guint8(tvb, 12); rwe_pos+=2) {
proto_tree_add_item(felica_tree, hf_felica_block_nbr, tvb,
rwe_pos+1, 1, ENC_BIG_ENDIAN);
}
I've found that removing the extraneous "+1" from that code will cause
all of the IDs to be "128" (which is incorrect) - so it's probably
just a case of trying to break the loop at the right time.
For what it's worth, this also seems to work (with caveats):
/* Start counting from 13 */
for (rwe_pos = 13; tvb_get_guint8(tvb, 12) < rwe_pos; rwe_pos+=2) {
printf (rwe_pos);
proto_tree_add_item(felica_tree, hf_felica_block_nbr,
tvb, rwe_pos+1, 1, ENC_BIG_ENDIAN);
}
In that case, I see the following error messages on stdout:
21:01:04 Warn Dissector bug, protocol FeliCa, in packet 5:
More than 1000000 items in the tree -- possible infinite loop
21:01:04 Warn Dissector bug, protocol FeliCa, in packet 8:
More than 1000000 items in the tree -- possible infinite loop
After trying your initial examples, and doing some of my own
experimentation, I've came to the conclusion that I can either
"successfully fail" and obtain all of the block IDs along with an
error message; or "fail successfully" and obtain nothing - since the
conditions being tested are contradictory (e.g. the number of blocks
is less than the position - therefore, we don't move the cursor).
Tyson.
On 22 January 2012 18:16, Chris Maynard <Chris.Maynard@xxxxxxxxx> wrote:
> Tyson Key <tyson.key@...> writes:
>
>> My (partially working) iteration code looks like:
>>
>> /* Start counting from 13 */
>> for (rwe_pos = 13; rwe_pos < tvb_get_guint8(tvb, 13); rwe_pos++) {
>> proto_tree_add_item(felica_tree, hf_felica_block_nbr, tvb,
>> rwe_pos + 1, 1, ENC_BIG_ENDIAN);
>> }
>
> How about something like this:
>
> /* Start counting from 14 */
> for (rwe_pos = 14; rwe_pos < tvb_get_guint8(tvb, 12); rwe_pos+=2) {
> proto_tree_add_item(felica_tree, hf_felica_block_nbr, tvb, rwe_pos, 1,
> ENC_BIG_ENDIAN);
> }
>
> ... or if you want the 0x80 byte highlighted as part of the block number
> (instead of skipping it), then do something like:
>
> /* Start counting from 13 */
> for (rwe_pos = 13; rwe_pos < tvb_get_guint8(tvb, 12); rwe_pos+=2) {
> proto_tree_add_uint(felica_tree, hf_felica_block_nbr, tvb, rwe_pos, 2,
> tvb_get_guint8(tvb, rwe_pos + 1));
> }
>
> - Chris
>
>
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