2 -- Copyright (C) 2009 Tobias Markmann
4 -- This project is MIT/X11 licensed. Please see the
5 -- COPYING file in the source package for more information.
8 local st = require "util.stanza";
9 local zlib = require "zlib";
11 local xmlns_compression_feature = "http://jabber.org/features/compress"
12 local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
13 local xmlns_stream = "http://etherx.jabber.org/streams";
14 local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up();
16 local compression_level = module:get_option("compression_level");
17 -- if not defined assume admin wants best compression
18 if compression_level == nil then compression_level = 9 end;
21 compression_level = tonumber(compression_level);
22 if not compression_level or compression_level < 1 or compression_level > 9 then
23 module:log("warn", "Invalid compression level in config: %s", tostring(compression_level));
24 module:log("warn", "Module loading aborted. Compression won't be available.");
28 module:add_event_hook("stream-features",
29 function (session, features)
30 if not session.compressed then
31 -- FIXME only advertise compression support when TLS layer has no compression enabled
32 features:add_child(compression_stream_feature);
37 module:hook("s2s-stream-features",
39 local session, features = data.session, data.features;
40 -- FIXME only advertise compression support when TLS layer has no compression enabled
41 if not session.compressed then
42 features:add_child(compression_stream_feature);
47 -- Hook to activate compression if remote server supports it.
48 module:hook_stanza(xmlns_stream, "features",
49 function (session, stanza)
50 if not session.compressed then
51 -- does remote server support compression?
52 local comp_st = stanza:child_with_name("compression");
54 -- do we support the mechanism
55 for a in comp_st:children() do
56 local algorithm = a[1]
57 if algorithm == "zlib" then
58 session.sends2s(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib"))
59 session.log("info", "Enabled compression using zlib.")
63 session.log("debug", "Remote server supports no compression algorithm we support.")
70 -- returns either nil or a fully functional ready to use inflate stream
71 local function get_deflate_stream(session)
72 local status, deflate_stream = pcall(zlib.deflate, compression_level);
73 if status == false then
74 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
75 (session.sends2s or session.send)(error_st);
76 session.log("error", "Failed to create zlib.deflate filter.");
77 module:log("error", deflate_stream);
83 -- returns either nil or a fully functional ready to use inflate stream
84 local function get_inflate_stream(session)
85 local status, inflate_stream = pcall(zlib.inflate);
86 if status == false then
87 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
88 (session.sends2s or session.send)(error_st);
89 session.log("error", "Failed to create zlib.deflate filter.");
90 module:log("error", inflate_stream);
96 -- setup compression for a stream
97 local function setup_compression(session, deflate_stream)
98 local old_send = (session.sends2s or session.send);
100 local new_send = function(t)
101 --TODO: Better code injection in the sending process
103 local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
104 if status == false then
106 condition = "undefined-condition";
108 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
110 module:log("warn", compressed);
113 session.conn:write(compressed);
116 if session.sends2s then session.sends2s = new_send
117 elseif session.send then session.send = new_send end
120 -- setup decompression for a stream
121 local function setup_decompression(session, inflate_stream)
122 local old_data = session.data
123 session.data = function(conn, data)
124 local status, decompressed, eof = pcall(inflate_stream, data);
125 if status == false then
127 condition = "undefined-condition";
129 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
131 module:log("warn", decompressed);
134 old_data(conn, decompressed);
138 module:add_handler({"s2sout_unauthed", "s2sout"}, "compressed", xmlns_compression_protocol,
139 function(session ,stanza)
140 session.log("debug", "Activating compression...")
141 -- create deflate and inflate streams
142 deflate_stream = get_deflate_stream(session);
143 if not deflate_stream then return end
145 inflate_stream = get_inflate_stream(session);
146 if not inflate_stream then return end
148 -- setup compression for session.w
149 setup_compression(session, deflate_stream);
151 -- setup decompression for session.data
152 setup_decompression(session, inflate_stream);
153 local session_reset_stream = session.reset_stream;
154 session.reset_stream = function(session)
155 session_reset_stream(session);
156 setup_decompression(session, inflate_stream);
159 session:reset_stream();
160 local default_stream_attr = {xmlns = "jabber:server", ["xmlns:stream"] = "http://etherx.jabber.org/streams",
161 ["xmlns:db"] = 'jabber:server:dialback', version = "1.0", to = session.to_host, from = session.from_host};
162 session.sends2s("<?xml version='1.0'?>");
163 session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag());
164 session.compressed = true;
168 module:add_handler({"c2s_unauthed", "c2s", "s2sin_unauthed", "s2sin"}, "compress", xmlns_compression_protocol,
169 function(session, stanza)
170 -- fail if we are already compressed
171 if session.compressed then
172 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
173 (session.sends2s or session.send)(error_st);
174 session.log("warn", "Tried to establish another compression layer.");
177 -- checking if the compression method is supported
178 local method = stanza:child_with_name("method")[1];
179 if method == "zlib" then
180 session.log("info", method.." compression selected.");
182 -- create deflate and inflate streams
183 deflate_stream = get_deflate_stream(session);
184 if not deflate_stream then return end
186 inflate_stream = get_inflate_stream(session);
187 if not inflate_stream then return end
189 (session.sends2s or session.send)(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
190 session:reset_stream();
192 -- setup compression for session.w
193 setup_compression(session, deflate_stream);
195 -- setup decompression for session.data
196 setup_decompression(session, inflate_stream);
198 local session_reset_stream = session.reset_stream;
199 session.reset_stream = function(session)
200 session_reset_stream(session);
201 setup_decompression(session, inflate_stream);
204 session.compressed = true;
206 session.log("info", method.." compression selected. But we don't support it.");
207 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
208 (session.sends2s or session.send)(error_st);