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-- SPDX-License-Identifier: GPL-3.0-or-later
local M = {} -- the module
local ffi = require('ffi')
function M.config(cfg)
if not cfg then return end
-- Beware that the timeout is only considered at certain points in time;
-- approximately at multiples of KR_CONN_RTT_MAX.
M.timeout = cfg.timeout or 3*sec
local targets_split = policy.forward_convert_targets(cfg.options, cfg.targets)
M.data_src = ffi.new('struct kr_query_data_src')
M.data_src.initialized = true
M.data_src.all_set = false
M.data_src.rule_depth = 0
assert(cfg.options.auth or false == false)
M.data_src.flags.is_auth = false
M.data_src.flags.is_tcp = false
assert(cfg.options.dnssec or true == true)
M.data_src.flags.is_nods = false
M.data_src.targets_ptr.len = #cfg.targets * ffi.C.KR_SOCKADDR_SIZE
M.targets_ptr_data = ffi.new('char [?]', M.data_src.targets_ptr.len)
M.data_src.targets_ptr.data = M.targets_ptr_data -- TODO: explain
ffi.C.kr_rule_coalesce_targets(targets_split, M.targets_ptr_data)
end
M.layer = {}
M.layer.produce = function (state, req, pkt)
if not M.data_src or state == kres.FAIL or state == kres.DONE then return state end
local qry = req:current()
if qry.flags.FALLBACK_DISABLE then return state end
-- 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_qry(qry, ffi.C.LOG_GRP_SRVSTALE,
' => no reachable NS, activating fallback forwarding',
kres.dname2str(qry:name()))
qry.data_src = M.data_src
qry.flags.FORWARD = true
qry.flags.STUB = false
if qry.data_src.flags.is_tcp then qry.flags.TCP = true end
ffi.C.kr_make_query(qry, pkt)
end
return state
end
return M
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