-- Prosody IM -- Copyright (C) 2009-2012 Tobias Markmann -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local st = require "util.stanza"; local zlib = require "zlib"; local pcall = pcall; local tostring = tostring; local xmlns_compression_feature = "http://jabber.org/features/compress" local xmlns_compression_protocol = "http://jabber.org/protocol/compress" local xmlns_stream = "http://etherx.jabber.org/streams"; local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up(); local add_filter = require "util.filters".add_filter; local compression_level = module:get_option_number("compression_level", 7); if not compression_level or compression_level < 1 or compression_level > 9 then module:log("warn", "Invalid compression level in config: %s", tostring(compression_level)); module:log("warn", "Module loading aborted. Compression won't be available."); return; end module:hook("stream-features", function(event) local origin, features = event.origin, event.features; if not origin.compressed and (origin.type == "c2s" or origin.type == "s2sin" or origin.type == "s2sout") then -- FIXME only advertise compression support when TLS layer has no compression enabled features:add_child(compression_stream_feature); end end); module:hook("s2s-stream-features", function(event) local origin, features = event.origin, event.features; -- FIXME only advertise compression support when TLS layer has no compression enabled if not origin.compressed and (origin.type == "c2s" or origin.type == "s2sin" or origin.type == "s2sout") then features:add_child(compression_stream_feature); end end); -- Hook to activate compression if remote server supports it. module:hook_stanza(xmlns_stream, "features", function (session, stanza) if not session.compressed and (session.type == "c2s" or session.type == "s2sin" or session.type == "s2sout") then -- does remote server support compression? local comp_st = stanza:child_with_name("compression"); if comp_st then -- do we support the mechanism for a in comp_st:children() do local algorithm = a[1] if algorithm == "zlib" then session.sends2s(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib")) session.log("debug", "Enabled compression using zlib.") return true; end end session.log("debug", "Remote server supports no compression algorithm we support.") end end end , 250); -- returns either nil or a fully functional ready to use inflate stream local function get_deflate_stream(session) local status, deflate_stream = pcall(zlib.deflate, compression_level); if status == false then local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); (session.sends2s or session.send)(error_st); session.log("error", "Failed to create zlib.deflate filter."); module:log("error", "%s", tostring(deflate_stream)); return end return deflate_stream end -- returns either nil or a fully functional ready to use inflate stream local function get_inflate_stream(session) local status, inflate_stream = pcall(zlib.inflate); if status == false then local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); (session.sends2s or session.send)(error_st); session.log("error", "Failed to create zlib.inflate filter."); module:log("error", "%s", tostring(inflate_stream)); return end return inflate_stream end -- setup compression for a stream local function setup_compression(session, deflate_stream) add_filter(session, "bytes/out", function(t) local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync'); if status == false then module:log("warn", "%s", tostring(compressed)); session:close({ condition = "undefined-condition"; text = compressed; extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed"); }); return; end return compressed; end); end -- setup decompression for a stream local function setup_decompression(session, inflate_stream) add_filter(session, "bytes/in", function(data) local status, decompressed, eof = pcall(inflate_stream, data); if status == false then module:log("warn", "%s", tostring(decompressed)); session:close({ condition = "undefined-condition"; text = decompressed; extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed"); }); return; end return decompressed; end); end module:hook("stanza/http://jabber.org/protocol/compress:compressed", function(event) local session = event.origin; if session.type == "s2sout_unauthed" or session.type == "s2sout" then session.log("debug", "Activating compression...") -- create deflate and inflate streams local deflate_stream = get_deflate_stream(session); if not deflate_stream then return true; end local inflate_stream = get_inflate_stream(session); if not inflate_stream then return true; end -- setup compression for session.w setup_compression(session, deflate_stream); -- setup decompression for session.data setup_decompression(session, inflate_stream); session:reset_stream(); local default_stream_attr = {xmlns = "jabber:server", ["xmlns:stream"] = "http://etherx.jabber.org/streams", ["xmlns:db"] = 'jabber:server:dialback', version = "1.0", to = session.to_host, from = session.from_host}; session.sends2s("<?xml version='1.0'?>"); session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag()); session.compressed = true; return true; end end); module:hook("stanza/http://jabber.org/protocol/compress:compress", function(event) local session, stanza = event.origin, event.stanza; if session.type == "c2s" or session.type == "s2sin" or session.type == "c2s_unauthed" or session.type == "s2sin_unauthed" then -- fail if we are already compressed if session.compressed then local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); (session.sends2s or session.send)(error_st); session.log("debug", "Client tried to establish another compression layer."); return true; end -- checking if the compression method is supported local method = stanza:child_with_name("method"); method = method and (method[1] or ""); if method == "zlib" then session.log("debug", "zlib compression enabled."); -- create deflate and inflate streams local deflate_stream = get_deflate_stream(session); if not deflate_stream then return true; end local inflate_stream = get_inflate_stream(session); if not inflate_stream then return true; end (session.sends2s or session.send)(st.stanza("compressed", {xmlns=xmlns_compression_protocol})); session:reset_stream(); -- setup compression for session.w setup_compression(session, deflate_stream); -- setup decompression for session.data setup_decompression(session, inflate_stream); session.compressed = true; elseif method then session.log("debug", "%s compression selected, but we don't support it.", tostring(method)); local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method"); (session.sends2s or session.send)(error_st); else (session.sends2s or session.send)(st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed")); end return true; end end);