diff options
Diffstat (limited to 'net/resolvers')
| -rw-r--r-- | net/resolvers/service.lua | 81 |
1 files changed, 68 insertions, 13 deletions
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 |