cache entry_list: fix crash on insertion via lua

When inserting NS or xNAME, we could get into this place with qry == NULL, and we'd crash when trying to use the memory pool. Let's simply use the stack instead.

@jvcelak: I tested with code like this:

modules.unload('priming') -- annoying log burst

cache.open(100*MB)
cache.clear() -- not required; just practical for testing changes

local ffi = require('ffi')
local c = kres.context().cache
ns_name = todname('ns12.example.com')
local ns_addr = '\127\0\0\9'
local ttl = 2^30 -- 34 years; but cache.max_ttl() will cut it down
local rr = kres.rrset(ns_name, kres.type.A, kres.class.IN, ttl)
assert(rr:add_rdata(ns_addr, #ns_addr))
assert(c:insert(rr, nil, ffi.C.KR_RANK_SECURE + ffi.C.KR_RANK_AUTH))

rr_ns = kres.rrset(todname('example.com'), kres.type.NS, kres.class.IN, ttl)
assert(rr_ns:add_rdata(ns_name, #ns_name))
assert(c:insert(rr_ns, nil, ffi.C.KR_RANK_INSECURE + ffi.C.KR_RANK_AUTH))

c:commit()

EDIT: added KR_RANK_AUTH, as that might be closer to what people expect.

The lower rank can be flipped to control whether the subtree is signed or not. If it is, you might want/need to insert a DS, too.

EDIT years later: factored out TTL and increased to years.

added 8 commits

• be5c1633...3d62d431 - 7 commits from branch master
• 8c655e73 - cache entry_list: fix crash on insertion via lua

Compare with previous version

added bug label

changed milestone to %4.3.0

The example above does not work for me, an explicit query for nic.cz NS ignores cache content:

[00000.00][plan] plan 'nic.cz.' type 'NS' uid [53091.00]
[53091.00][iter]   'nic.cz.' type 'NS' new uid was assigned .01, parent uid .00
[53091.01][cach]   => skipping exact RR: rank 010 (min. 030), new TTL 3582

It start working if I replace ffi.C.KR_RANK_INSECURE with bit.bor(ffi.C.KR_RANK_AUTH, ffi.C.KR_RANK_INSECURE).

Right, for an explicit query you need a child-side record, and KR_RANK_INSECURE by itself is just parent-side. Still, for following a delegation it should be fine.

BTW, + should be fine instead of bor, for simplicity.

added 2 commits

• f95d0cd4 - cache: integration test for explicit NS insertion
• 5aa5f573 - tests: skip Deckard integration tests if sendmmsg is enabled

Compare with previous version

added 15 commits

• 5aa5f573...3466da3a - 12 commits from branch master
• 1263bc98 - cache entry_list: fix crash on insertion via lua
• 18eb1185 - cache: integration test for explicit NS insertion
• 7ed217e8 - tests: skip Deckard integration tests if sendmmsg is enabled

Compare with previous version

merged

mentioned in commit 4eaf63bc

Related: !651 (closed)

mentioned in merge request !651 (closed)

mentioned in issue #428 (closed)

mentioned in merge request !964 (merged)