Hi Pavel, 2016-12-21 15:37 GMT+01:00 Pavel Strnad <strn...@tiscali.cz>:
> Hello, > > I am trying to understand the difference in usage of NO_BOUND or UINT_MAX > in the place of max parameter in dissect_per_constrained_integer() > function. In my case aligned PER variant. > > > > From packet-per.h: > > #define NO_BOUND -1 > > guint32 dissect_per_constrained_integer(tvbuff_t *tvb, guint32 offset, > asn1_ctx_t *actx, proto_tree *tree, int hf_index, guint32 min, guint32 max, > guint32 *value, gboolean has_extension); > > > > Based on that it looks like that there is no different dissection of > following two asn.1 definitions? > Correct, semi-constrained integer does not seem to be managed properly. This matches the comment found in line 1283. > 1) seconds INTEGER (0..4294967295) > > 2) seconds INTEGER (0..MAX) where MAX translates to > NO_BOUND=4294967295 using asn2wrs > > > > Reading X.691 (aligned PER) wireshark seems to dissect well the 1st case > that is using size constraint but not the 2nd case > > where semi-constraint size is used and the length determinant should > include padding bits in the case of aligned PER. > > > > I would like to try to fix it myself but will need some hint how to > differentiate these two cases and keep API unchanged? > IMHO you can't without changing the API. Maybe we would need to extra booleans indicating whether the min and / or max values are bounded or not, and adapt asn2wrs generator accordingly. This way we could drop the NO_BOUND define Note that this sounds like a non trivial project because: - as indicated in the comments, dissect_per_constrained_integer only handle 32 bits integers and dissect_per_constrained_integer_64b only handles 64 bits integers, so both needs to be adapted - MIN or MAX parameters do not seem properly handled in other types also, and any change done in dissect_per_constrained_integer(_64b) needs to be reflected in the caller functions and any other making use of NO_BOUND Regards, Pascal.
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