instead of allowing a NULL nametree in dns_nametree_covered(),
require nametree to exist, and ensure that the nametrees defined
for view and resolver objects are always created.
name trees can now also hold trees of counters. each time a name
dns_nametree_add() is called with a given name, the counter for that
name is incremented; the name is not deleted until dns_nametree_delete()
is called the same number of times.
this is meant to be used for synth-from-dnssec, which is incremented for
each key defined at a name, and decremented when a key is removed, the
name must continue to exist until the number of keys has reached zero.
name trees can now hold either boolean values or bit fields. the
type is selected when the name tree is created.
the behavior of dns_nametree_add() differs slightly beteween the types:
in a boolean tree adding an existing name will return ISC_R_EXISTS,
but in a bitfield tree it simply sets the specified bit in the bitfield
and returns ISC_R_SUCCESS.
the functions for disabling DNSSEC signing algorithms and DS digest
algorithms in resolver.c had a lot of duplicated code.
this commit adds functions to implement a "bitfield tree", which is
(currently) an RBT in which the node data contains arbitrary-sized
bitfields to indicate whether a value has been added at the given
node or not. (it can be changed to a QP trie later.)
it also replaces the functions dns_resolver_disable_algorithm(),
dns_resolver_algorithm_supported(), dns_resolver_disable_ds_digest()
and dns_resolver_ds_digest_supported() with simple wrappers that call
the new functions.
replace the use of RBTs for deny-answer-aliases, the exclude
lists for deny-answer-aliases and deny-answer-addresses, and
dnssec-must-be-secure, with name trees.
this is a QP trie of boolean values to indicate whether a name is
included in or excluded from some policy. this can be used for
synth-from-dnssec, deny-answer-aliases, etc.
as dns_transport_find() is only concerned with finding an exact
match on the specified name it doesn't need to use a tree data
structure internally, we can replace the RBTs with hash tables.
Use the new isc_mem_c*() calloc-like API for allocations that are
zeroed.
In turn, this also fixes couple of incorrect usage of the ISC_MEM_ZERO
for structures that need to be zeroed explicitly.
There are few places where isc_mem_cput() is used on structures with a
flexible member (or similar).
The aim is to match unsafe patterns of allocation size arithmetic
and turn them into safe calls to the new `isc_mem_cget()`,
`isc_mem_creget()`, and `isc_mem_cput()`.
Add new isc_mem_cget(), isc_mem_creget(), and isc_mem_cput() macros to
complement the isc_mem_callocate() (which works like calloc()).
The overflow checks are implemented as macros in the <isc/mem.h>, so
that the compiler can see that the element size is constant: it should
always be `sizeof(something)`.
