Basic ACL checker gets request field via getters that are
NPE-free, therefore we don't need to worry about function
invocations on nil structures.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
ACL has to classify request senders by roles:
- owner of the container,
- request from container or inner ring node,
- any other request.
According to this roles ACL checker use different
bits of basic ACL to grant or deny access.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
