File

net/connect.lua @ 12056:e62025f949f9

mod_smacks: Limit queue memory consumption using new util This brings back the queue size limit that was once added, then removed because destroying the session when reaching the limit was not great. Instead, the queue wraps and overwrites the oldest unacked stanza on the assumption that it will probably be acked anyway and thus does not need to be delivered. If those discarded stanzas turn out to be needed on resumption then the resumption fails.
author Kim Alvefur <zash@zash.se>
date Tue, 14 Dec 2021 20:00:45 +0100
parent 11903:baf69f254753
child 12205:a2e6605303fa
line wrap: on
line source

local server = require "net.server";
local log = require "util.logger".init("net.connect");
local new_id = require "util.id".short;

-- TODO #1246 Happy Eyeballs
-- FIXME RFC 6724
-- FIXME Error propagation from resolvers doesn't work
-- FIXME #1428 Reuse DNS resolver object between service and basic resolver
-- FIXME #1429 Close DNS resolver object when done

local pending_connection_methods = {};
local pending_connection_mt = {
	__name = "pending_connection";
	__index = pending_connection_methods;
	__tostring = function (p)
		return "<pending connection "..p.id.." to "..tostring(p.target_resolver.hostname)..">";
	end;
};

function pending_connection_methods:log(level, message, ...)
	log(level, "[pending connection %s] "..message, self.id, ...);
end

-- pending_connections_map[conn] = pending_connection
local pending_connections_map = {};

local pending_connection_listeners = {};

local function attempt_connection(p)
	p:log("debug", "Checking for targets...");
	if p.conn then
		pending_connections_map[p.conn] = nil;
		p.conn = nil;
	end
	p.target_resolver:next(function (conn_type, ip, port, extra)
		if not conn_type then
			-- No more targets to try
			p:log("debug", "No more connection targets to try", p.target_resolver.last_error);
			if p.listeners.onfail then
				p.listeners.onfail(p.data, p.last_error or p.target_resolver.last_error or "unable to resolve service");
			end
			return;
		end
		p:log("debug", "Next target to try is %s:%d", ip, port);
		local conn, err = server.addclient(ip, port, pending_connection_listeners, p.options.pattern or "*a", p.options.sslctx, conn_type, extra);
		if not conn then
			log("debug", "Connection attempt failed immediately: %s", err);
			p.last_error = err or "unknown reason";
			return attempt_connection(p);
		end
		p.conn = conn;
		pending_connections_map[conn] = p;
	end);
end

function pending_connection_listeners.onconnect(conn)
	local p = pending_connections_map[conn];
	if not p then
		log("warn", "Successful connection, but unexpected! Closing.");
		conn:close();
		return;
	end
	pending_connections_map[conn] = nil;
	p:log("debug", "Successfully connected");
	conn:setlistener(p.listeners, p.data);
	return p.listeners.onconnect(conn);
end

function pending_connection_listeners.ondisconnect(conn, reason)
	local p = pending_connections_map[conn];
	if not p then
		log("warn", "Failed connection, but unexpected!");
		return;
	end
	p.last_error = reason or "unknown reason";
	p:log("debug", "Connection attempt failed: %s", p.last_error);
	attempt_connection(p);
end

local function connect(target_resolver, listeners, options, data)
	local p = setmetatable({
		id = new_id();
		target_resolver = target_resolver;
		listeners = assert(listeners);
		options = options or {};
		data = data;
	}, pending_connection_mt);

	p:log("debug", "Starting connection process");
	attempt_connection(p);
end

return {
	connect = connect;
};