diff options
Diffstat (limited to 'net/resolvers')
| -rw-r--r-- | net/resolvers/basic.lua | 160 | ||||
| -rw-r--r-- | net/resolvers/service.lua | 81 |
2 files changed, 148 insertions, 93 deletions
diff --git a/net/resolvers/basic.lua b/net/resolvers/basic.lua index 305bce76..15338ff4 100644 --- a/net/resolvers/basic.lua +++ b/net/resolvers/basic.lua @@ -2,13 +2,59 @@ 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) + 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 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 +64,7 @@ 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 +74,45 @@ 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); + ipv6 = do_dns_lookup(self, dns_resolver, "AAAA", self.hostname); + 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 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 +137,7 @@ 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 diff --git a/net/resolvers/service.lua b/net/resolvers/service.lua index 3810cac8..a7ce76a3 100644 --- a/net/resolvers/service.lua +++ b/net/resolvers/service.lua @@ -2,23 +2,78 @@ local adns = require "net.adns"; local basic = require "net.resolvers.basic"; local inet_pton = require "util.net".pton; local idna_to_ascii = require "util.encodings".idna.to_ascii; -local unpack = table.unpack or unpack; -- luacheck: ignore 113 local methods = {}; local resolver_mt = { __index = methods }; +local function new_target_selector(rrset) + local rr_count = rrset and #rrset; + if not rr_count or rr_count == 0 then + rrset = nil; + else + table.sort(rrset, function (a, b) return a.srv.priority < b.srv.priority end); + end + local rrset_pos = 1; + local priority_bucket, bucket_total_weight, bucket_len, bucket_used; + return function () + if not rrset then return; end + + if not priority_bucket or bucket_used >= bucket_len then + if rrset_pos > rr_count then return; end -- Used up all records + + -- Going to start on a new priority now. Gather up all the next + -- records with the same priority and add them to priority_bucket + priority_bucket, bucket_total_weight, bucket_len, bucket_used = {}, 0, 0, 0; + local current_priority; + repeat + local curr_record = rrset[rrset_pos].srv; + if not current_priority then + current_priority = curr_record.priority; + elseif current_priority ~= curr_record.priority then + break; + end + table.insert(priority_bucket, curr_record); + bucket_total_weight = bucket_total_weight + curr_record.weight; + bucket_len = bucket_len + 1; + rrset_pos = rrset_pos + 1; + until rrset_pos > rr_count; + end + + bucket_used = bucket_used + 1; + local n, running_total = math.random(0, bucket_total_weight), 0; + local target_record; + for i = 1, bucket_len do + local candidate = priority_bucket[i]; + if candidate then + running_total = running_total + candidate.weight; + if running_total >= n then + target_record = candidate; + bucket_total_weight = bucket_total_weight - candidate.weight; + priority_bucket[i] = nil; + break; + end + end + end + return target_record; + end; +end + -- Find the next target to connect to, and -- pass it to cb() function methods:next(cb) - if self.targets then - if not self.resolver then - if #self.targets == 0 then + if self.resolver or self._get_next_target then + if not self.resolver then -- Do we have a basic resolver currently? + -- We don't, so fetch a new SRV target, create a new basic resolver for it + local next_srv_target = self._get_next_target and self._get_next_target(); + if not next_srv_target then + -- No more SRV targets left cb(nil); return; end - local next_target = table.remove(self.targets, 1); - self.resolver = basic.new(unpack(next_target, 1, 4)); + -- Create a new basic resolver for this SRV target + self.resolver = basic.new(next_srv_target.target, next_srv_target.port, self.conn_type, self.extra); end + -- Look up the next (basic) target from the current target's resolver self.resolver:next(function (...) if self.resolver then self.last_error = self.resolver.last_error; @@ -31,6 +86,9 @@ function methods:next(cb) end end); return; + elseif self.in_progress then + cb(nil); + return; end if not self.hostname then @@ -39,9 +97,9 @@ function methods:next(cb) return; end - local targets = {}; + self.in_progress = true; + local function ready() - self.targets = targets; self:next(cb); end @@ -63,7 +121,7 @@ function methods:next(cb) if #answer == 0 then if self.extra and self.extra.default_port then - table.insert(targets, { self.hostname, self.extra.default_port, self.conn_type, self.extra }); + self.resolver = basic.new(self.hostname, self.extra.default_port, self.conn_type, self.extra); else self.last_error = "zero SRV records found"; end @@ -77,10 +135,7 @@ function methods:next(cb) return; end - table.sort(answer, function (a, b) return a.srv.priority < b.srv.priority end); - for _, record in ipairs(answer) do - table.insert(targets, { record.srv.target, record.srv.port, self.conn_type, self.extra }); - end + self._get_next_target = new_target_selector(answer); else self.last_error = err; end |