GATT/ATT use little-endian byte order format for 128-bit UUID. No matter
the system byte order representation, internally the core will handle
128-bit UUID on big-endian format.
Use number instead of "min_len", which is easier to review (with help of
the documented parameter sizes).
valuelen is redundant as *vlen can be used directly.
Both userspace and kernel enforce a minimum ATT MTU of 23 octets, which
is also used as minimum size for buffers passed to ATT encoding
functions. Therefore, it is unnecessary to perform these checks on ATT
requests that are guaranteed to fit into 23 octets.
Also document ATT parameter lengths where a constant is being used for
calculating the PDU length.
Fix these build errors:
attrib/att.c: In function ‘dec_read_by_grp_req’:
attrib/att.c:165:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c:170:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c: In function ‘dec_read_by_type_req’:
attrib/att.c:393:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c:402:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
When encoding an att_data_list we need to make sure that each element
lenght of the data list will not exceed 255, because that information
will be encoded as a octet later.
size_t/ssize_t/off_t/etc are more appropriate for variables denoting
some kind of size than simply using int.
This patch includes a couple of other related changes to avoid gcc
signedness errors resulting from it treating (for whatever reason) const
variables and integer literals as signed.
This patch avoids invalid memory access when decoding ATT read response
PDUs. The ATT_MTU value is a per ATT Bearer value defined by the higher
layer specification.
This patch fixes command timeout handling. Previously attrib_destroy was
explicitly called which ignored any reference holders. This patch fixes
the issue by first passing errors to command callbacks and after that
marking the GAttrib object as stale so no further operations can be
done.
The enconding and decoding of ATT pdus should be kept as much
free of dependences from other parts of the code as possible, so
it can be used in many contexts.
In this case, for encoding and decoding notifications and indications
we did have to pass an instance of an attribute instead of direct
values.
On commit 6a6da5de10 the struct
attribute "data[0]" member was replaced with a dynamically allocated
"data" pointer. This commit fixes remaining places where the old
allocation scheme was still assumed.
This patch puts the new UUID functions into use for GATT-related
code, and adds some convenience functions to ATT API (att.h).
Example GATT server is also changed.
Implement encoders/decoders for Write Request/Response and the handling
on attribute server. The attribute client still uses the Write Command
because currently SetProperty() has no means to wait for the server
response.
