As far as I can tell, no DHCPv6 RFC specifies this option. The handling
for the zero option was added in #17736 by @benpicco to fix issues
encountered while trying to retrieve a DHCHPv6 lease. However, I
strongly suspect that the zero option was encountered in this case due
to an out-of-bounds read performed in RIOT's DHCPv6 client
implementation (i.e. the option parsing loop read beyond the packet
bounds). This issue was fixed in #18307 and I strongly suspect that it
should also fix the issue @benpicco originally encountered in #17736. As
such, I propose that we remove the if statement which treats the zero
option as an end-of-payload marker.
Fixes#18309
Due to the lack of new official avr-libc releases (which includes the
vendor header files needed to support different version of MCUs),
support for new MCUs was lacking. Distributions such as Debian addressed
this by extending the upstream code with vendor header files directly
obtained from Atmel / Microchip, but without paying attention to
details. As such, a naming inconsistency (ASIZE vs ASPACE) between
officially supported MCUs and new MCUs was introduced.
Now that avr-libc 2.1.0 is officially released, hardware support for new
MCUs is provided by upstream out of the box and only ASIZE is used as
name. This commit adds a bit of glue code to create aliases for ASIZE on
older avr-libc versions where needed. This fixes compilation with the
new avr-libc release and results in more consistent code.
As a leftovers from https://github.com/RIOT-OS/RIOT/pull/18355 are still
present that check for `MODULE_SHELL_COMMANDS` rather than
`MODULE_SHELL_CMDS`. This updates the conditionals as needed.
This header-only module provides a `string_utils.h` that currently
only provides the non-standard function `explicit_bzero()` to securely
wipe memory. It may be extended with other utility functions in the
future.
The ztimer64_xtimer_compat module is not automatically enabled when
ztimer provides xtimer compatibility. It does not provide the
xtimer_usec_from_ticks64 function, but that was not particularly used
anyway. A header file became unavailable but was not needed.
