mod_s2s: Use a separate resolver object for each outgoing session
Cleaner approach hopefully fixes problems with some peoples' DNS
hanging after a while, failed DNS when a large number of queries
are made at once, and source port re-use.
Related issues: #487, 761, #991, #992, #1001
--- a/plugins/mod_s2s/mod_s2s.lua Mon Sep 25 23:06:00 2017 +0100
+++ b/plugins/mod_s2s/mod_s2s.lua Mon Sep 25 23:12:47 2017 +0100
@@ -174,6 +174,7 @@
-- Stream is authorised, and ready for normal stanzas
function mark_connected(session)
+
local sendq = session.sendq;
local from, to = session.from_host, session.to_host;
@@ -205,6 +206,7 @@
session.sendq = nil;
end
+ session.resolver = nil;
session.ip_hosts = nil;
session.srv_hosts = nil;
end
--- a/plugins/mod_s2s/s2sout.lib.lua Mon Sep 25 23:06:00 2017 +0100
+++ b/plugins/mod_s2s/s2sout.lib.lua Mon Sep 25 23:12:47 2017 +0100
@@ -49,6 +49,8 @@
initialize_filters(host_session);
host_session.version = 1;
+ host_session.resolver = adns.resolver();
+
-- Kick the connection attempting machine into life
if not s2sout.attempt_connection(host_session) then
-- Intentionally not returning here, the
@@ -84,9 +86,7 @@
if not err then -- This is our first attempt
log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
host_session.connecting = true;
- local handle;
- handle = adns.lookup(function (answer)
- handle = nil;
+ host_session.resolver:lookup(function (answer)
local srv_hosts = { answer = answer };
host_session.srv_hosts = srv_hosts;
host_session.srv_choice = 0;
@@ -168,7 +168,7 @@
local have_other_result = not(has_ipv4) or not(has_ipv6) or false;
if has_ipv4 then
- handle4 = adns.lookup(function (reply, err)
+ handle4 = host_session.resolver:lookup(function (reply, err)
handle4 = nil;
if reply and reply[#reply] and reply[#reply].a then
@@ -206,7 +206,7 @@
end
if has_ipv6 then
- handle6 = adns.lookup(function (reply, err)
+ handle6 = host_session.resolver:lookup(function (reply, err)
handle6 = nil;
if reply and reply[#reply] and reply[#reply].aaaa then