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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:26:00 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:26:00 +0000 |
commit | 830407e88f9d40d954356c3754f2647f91d5c06a (patch) | |
tree | d6a0ece6feea91f3c656166dbaa884ef8a29740e /modules/serve_stale/serve_stale.lua | |
parent | Initial commit. (diff) | |
download | knot-resolver-upstream/5.6.0.tar.xz knot-resolver-upstream/5.6.0.zip |
Adding upstream version 5.6.0.upstream/5.6.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'modules/serve_stale/serve_stale.lua')
-rw-r--r-- | modules/serve_stale/serve_stale.lua | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/modules/serve_stale/serve_stale.lua b/modules/serve_stale/serve_stale.lua new file mode 100644 index 0000000..faf07fb --- /dev/null +++ b/modules/serve_stale/serve_stale.lua @@ -0,0 +1,42 @@ +-- SPDX-License-Identifier: GPL-3.0-or-later +local M = {} -- the module + +local ffi = require('ffi') + +-- Beware that the timeout is only considered at certain points in time; +-- approximately at multiples of KR_CONN_RTT_MAX. +M.timeout = 3*sec + +M.callback = ffi.cast("kr_stale_cb", + function (ttl) --, name, type, qry) + --log_debug(ffi.C.SRVSTALE, ' => called back with TTL: ' .. tostring(ttl)) + if ttl + 3600 * 24 > 0 then -- at most one day stale + return 1 + else + return -1 + end + end) + +M.layer = { + produce = function (state, req) + local qry = req:current() + -- Don't do anything for priming, prefetching, etc. + -- TODO: not all cases detected ATM. + if qry.flags.NO_CACHE then return state end + + local now = ffi.C.kr_now() + local deadline = qry.creation_time_mono + M.timeout + if now > deadline or qry.flags.NO_NS_FOUND then + log_debug(ffi.C.LOG_GRP_SRVSTALE, ' => no reachable NS, using stale data') + qry.stale_cb = M.callback + -- TODO: probably start the same request that doesn't stale-serve, + -- but first we need some detection of non-interactive / internal requests. + -- resolve(kres.dname2str(qry.sname), qry.stype, qry.sclass) + end + + return state + end, +} + +return M + |