diff options
Diffstat (limited to '')
| -rw-r--r-- | modules/prefill/prefill.lua | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/modules/prefill/prefill.lua b/modules/prefill/prefill.lua new file mode 100644 index 0000000..f4a4288 --- /dev/null +++ b/modules/prefill/prefill.lua @@ -0,0 +1,199 @@ +-- SPDX-License-Identifier: GPL-3.0-or-later +local ffi = require('ffi') + +local rz_url = "https://www.internic.net/domain/root.zone" +local rz_local_fname = "root.zone" +local rz_ca_file = nil +local rz_event_id = nil + +local rz_default_interval = 86400 +local rz_https_fail_interval = 600 +local rz_import_error_interval = 600 +local rz_cur_interval = rz_default_interval +local rz_interval_randomizer_limit = 10 +local rz_interval_threshold = 5 +local rz_interval_min = 3600 + +local rz_first_try = true + +local prefill = {} + +-- hack for circular dependency between timer() and fill_cache() +local forward_references = {} + +local function stop_timer() + if rz_event_id then + event.cancel(rz_event_id) + rz_event_id = nil + end +end + +local function timer() + stop_timer() + worker.bg_worker.cq:wrap(forward_references.fill_cache) +end + +local function restart_timer(after) + stop_timer() + rz_event_id = event.after(after * sec, timer) +end + +local function display_delay(time) + local days = math.floor(time / 86400) + local hours = math.floor((time % 86400) / 3600) + local minutes = math.floor((time % 3600) / 60) + local seconds = math.floor(time % 60) + if days > 0 then + return string.format("%d days %02d hours", days, hours) + elseif hours > 0 then + return string.format("%02d hours %02d minutes", hours, minutes) + elseif minutes > 0 then + return string.format("%02d minutes %02d seconds", minutes, seconds) + end + return string.format("%02d seconds", seconds) +end + +-- returns: number of seconds the file is valid for +-- 0 indicates immediate download +local function get_file_ttl(fname) + local mtime = tonumber(ffi.C.kr_file_mtime(fname)) + + if mtime > 0 then + local age = os.time() - mtime + return math.max( + rz_cur_interval - age, + 0) + else + return 0 -- file does not exist, download now + end +end + +local function download(url, fname) + local kluautil = require('kluautil') + local file, rcode, errmsg + file, errmsg = io.open(fname, 'w') + if not file then + error(string.format("[prefil] unable to open file %s (%s)", + fname, errmsg)) + end + + log_info(ffi.C.LOG_GRP_PREFILL, "downloading root zone to file %s ...", fname) + rcode, errmsg = kluautil.kr_https_fetch(url, file, rz_ca_file) + if rcode == nil then + error(string.format("[prefil] fetch of `%s` failed: %s", url, errmsg)) + end + + file:close() +end + +local function import(fname) + local ret = ffi.C.zi_zone_import({ + zone_file = fname, + time_src = ffi.C.ZI_STAMP_MTIM, -- the file might be slightly older + }) + if ret == 0 then + log_info(ffi.C.LOG_GRP_PREFILL, "zone successfully parsed, import started") + else + error(string.format( + "[prefil] zone import failed: %s", ffi.C.knot_strerror(ret) + )) + end +end + +function forward_references.fill_cache() + local file_ttl = get_file_ttl(rz_local_fname) + + if file_ttl > rz_interval_threshold then + log_info(ffi.C.LOG_GRP_PREFILL, "root zone file valid for %s, reusing data from disk", + display_delay(file_ttl)) + else + local ok, errmsg = pcall(download, rz_url, rz_local_fname) + if not ok then + rz_cur_interval = rz_https_fail_interval + - math.random(rz_interval_randomizer_limit) + log_info(ffi.C.LOG_GRP_PREFILL, "cannot download new zone (%s), " + .. "will retry root zone download in %s", + errmsg, display_delay(rz_cur_interval)) + restart_timer(rz_cur_interval) + os.remove(rz_local_fname) + return + end + file_ttl = rz_default_interval + end + -- file is up to date, import + -- import/filter function gets executed after resolver/module + local ok, errmsg = pcall(import, rz_local_fname) + if not ok then + if rz_first_try then + rz_first_try = false + rz_cur_interval = 1 + else + rz_cur_interval = rz_import_error_interval + - math.random(rz_interval_randomizer_limit) + end + log_info(ffi.C.LOG_GRP_PREFILL, "root zone import failed (%s), retry in %s", + errmsg, display_delay(rz_cur_interval)) + else + -- re-download before TTL expires + rz_cur_interval = (file_ttl - rz_interval_threshold + - math.random(rz_interval_randomizer_limit)) + log_info(ffi.C.LOG_GRP_PREFILL, "root zone refresh in %s", + display_delay(rz_cur_interval)) + end + restart_timer(rz_cur_interval) +end + +function prefill.deinit() + stop_timer() +end + +-- process one item from configuration table +-- right now it supports only root zone because +-- prefill module uses global variables +local function config_zone(zone_cfg) + if zone_cfg.interval then + zone_cfg.interval = tonumber(zone_cfg.interval) + if zone_cfg.interval < rz_interval_min then + error(string.format('[prefil] refresh interval %d s is too short, ' + .. 'minimal interval is %d s', + zone_cfg.interval, rz_interval_min)) + end + rz_default_interval = zone_cfg.interval + rz_cur_interval = zone_cfg.interval + end + + rz_ca_file = zone_cfg.ca_file + + if not zone_cfg.url or not string.match(zone_cfg.url, '^https://') then + error('[prefil] option url must contain a ' + .. 'https:// URL of a zone file') + else + rz_url = zone_cfg.url + end +end + +function prefill.config(config) + if config == nil then return end -- e.g. just modules = { 'prefill' } + local root_configured = false + if type(config) ~= 'table' then + error('[prefil] configuration must be in table ' + .. '{owner name = {per-zone config}}') + end + for owner, zone_cfg in pairs(config) do + if owner ~= '.' then + error('[prefil] only root zone can be imported ' + .. 'at the moment') + else + config_zone(zone_cfg) + root_configured = true + end + end + if not root_configured then + error('[prefil] this module version requires configuration ' + .. 'for root zone') + end + + restart_timer(0) -- start now +end + +return prefill |