diff options
Diffstat (limited to 'net/resolvers/basic.lua')
| -rw-r--r-- | net/resolvers/basic.lua | 164 |
1 files changed, 84 insertions, 80 deletions
diff --git a/net/resolvers/basic.lua b/net/resolvers/basic.lua index 305bce76..3ef916a2 100644 --- a/net/resolvers/basic.lua +++ b/net/resolvers/basic.lua @@ -2,13 +2,61 @@ local adns = require "net.adns"; local inet_pton = require "util.net".pton; local inet_ntop = require "util.net".ntop; local idna_to_ascii = require "util.encodings".idna.to_ascii; -local unpack = table.unpack or unpack; -- luacheck: ignore 113 +local promise = require "util.promise"; +local t_move = require "util.table".move; local methods = {}; local resolver_mt = { __index = methods }; -- FIXME RFC 6724 +local function do_dns_lookup(self, dns_resolver, record_type, name, allow_insecure) + return promise.new(function (resolve, reject) + local ipv = (record_type == "A" and "4") or (record_type == "AAAA" and "6") or nil; + if ipv and self.extra["use_ipv"..ipv] == false then + return reject(("IPv%s disabled - %s lookup skipped"):format(ipv, record_type)); + elseif record_type == "TLSA" and self.extra.use_dane ~= true then + return reject("DANE disabled - TLSA lookup skipped"); + end + dns_resolver:lookup(function (answer, err) + if not answer then + return reject(err); + elseif answer.bogus then + return reject(("Validation error in %s lookup"):format(record_type)); + elseif not (answer.secure or allow_insecure) then + return reject(("Insecure response in %s lookup"):format(record_type)); + elseif answer.status and #answer == 0 then + return reject(("%s in %s lookup"):format(answer.status, record_type)); + end + + local targets = { secure = answer.secure }; + for _, record in ipairs(answer) do + if ipv then + table.insert(targets, { self.conn_type..ipv, record[record_type:lower()], self.port, self.extra }); + else + table.insert(targets, record[record_type:lower()]); + end + end + return resolve(targets); + end, name, record_type, "IN"); + end); +end + +local function merge_targets(ipv4_targets, ipv6_targets) + local result = { secure = ipv4_targets.secure and ipv6_targets.secure }; + local common_length = math.min(#ipv4_targets, #ipv6_targets); + for i = 1, common_length do + table.insert(result, ipv6_targets[i]); + table.insert(result, ipv4_targets[i]); + end + if common_length < #ipv4_targets then + t_move(ipv4_targets, common_length+1, #ipv4_targets, common_length+1, result); + elseif common_length < #ipv6_targets then + t_move(ipv6_targets, common_length+1, #ipv6_targets, common_length+1, result); + end + return result; +end + -- Find the next target to connect to, and -- pass it to cb() function methods:next(cb) @@ -18,7 +66,7 @@ function methods:next(cb) return; end local next_target = table.remove(self.targets, 1); - cb(unpack(next_target, 1, 4)); + cb(next_target[1], next_target[2], next_target[3], next_target[4], not not self.targets[1]); return; end @@ -28,91 +76,47 @@ function methods:next(cb) return; end - local secure = true; - local tlsa = {}; - local targets = {}; - local n = 3; - local function ready() - n = n - 1; - if n > 0 then return; end - self.targets = targets; + -- Resolve DNS to target list + local dns_resolver = adns.resolver(); + + local dns_lookups = { + ipv4 = do_dns_lookup(self, dns_resolver, "A", self.hostname, true); + ipv6 = do_dns_lookup(self, dns_resolver, "AAAA", self.hostname, true); + tlsa = do_dns_lookup(self, dns_resolver, "TLSA", ("_%d._%s.%s"):format(self.port, self.conn_type, self.hostname)); + }; + + promise.all_settled(dns_lookups):next(function (dns_results) + -- Combine targets, assign to self.targets, self:next(cb) + local have_ipv4 = dns_results.ipv4.status == "fulfilled"; + local have_ipv6 = dns_results.ipv6.status == "fulfilled"; + + if have_ipv4 and have_ipv6 then + self.targets = merge_targets(dns_results.ipv4.value, dns_results.ipv6.value); + elseif have_ipv4 then + self.targets = dns_results.ipv4.value; + elseif have_ipv6 then + self.targets = dns_results.ipv6.value; + else + self.targets = {}; + end + if self.extra and self.extra.use_dane then - if secure and tlsa[1] then - self.extra.tlsa = tlsa; + if self.targets.secure and dns_results.tlsa.status == "fulfilled" then + self.extra.tlsa = dns_results.tlsa.value; self.extra.dane_hostname = self.hostname; else self.extra.tlsa = nil; self.extra.dane_hostname = nil; end + elseif self.extra and self.extra.srv_secure then + self.extra.secure_hostname = self.hostname; end - self:next(cb); - end - -- Resolve DNS to target list - local dns_resolver = adns.resolver(); - - if not self.extra or self.extra.use_ipv4 ~= false then - dns_resolver:lookup(function (answer, err) - if answer then - secure = secure and answer.secure; - for _, record in ipairs(answer) do - table.insert(targets, { self.conn_type.."4", record.a, self.port, self.extra }); - end - if answer.bogus then - self.last_error = "Validation error in A lookup"; - elseif answer.status then - self.last_error = answer.status .. " in A lookup"; - end - else - self.last_error = err; - end - ready(); - end, self.hostname, "A", "IN"); - else - ready(); - end - - if not self.extra or self.extra.use_ipv6 ~= false then - dns_resolver:lookup(function (answer, err) - if answer then - secure = secure and answer.secure; - for _, record in ipairs(answer) do - table.insert(targets, { self.conn_type.."6", record.aaaa, self.port, self.extra }); - end - if answer.bogus then - self.last_error = "Validation error in AAAA lookup"; - elseif answer.status then - self.last_error = answer.status .. " in AAAA lookup"; - end - else - self.last_error = err; - end - ready(); - end, self.hostname, "AAAA", "IN"); - else - ready(); - end - - if self.extra and self.extra.use_dane == true then - dns_resolver:lookup(function (answer, err) - if answer then - secure = secure and answer.secure; - for _, record in ipairs(answer) do - table.insert(tlsa, record.tlsa); - end - if answer.bogus then - self.last_error = "Validation error in TLSA lookup"; - elseif answer.status then - self.last_error = answer.status .. " in TLSA lookup"; - end - else - self.last_error = err; - end - ready(); - end, ("_%d._tcp.%s"):format(self.port, self.hostname), "TLSA", "IN"); - else - ready(); - end + self:next(cb); + end):catch(function (err) + self.last_error = err; + self.targets = {}; + end); end local function new(hostname, port, conn_type, extra) @@ -137,7 +141,7 @@ local function new(hostname, port, conn_type, extra) hostname = ascii_host; port = port; conn_type = conn_type; - extra = extra; + extra = extra or {}; targets = targets; }, resolver_mt); end |