aboutsummaryrefslogtreecommitdiffstats
path: root/plugins/mod_compression.lua
blob: 802e182227fa9899a1d445d37844a40ed272f2a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
-- Prosody IM
-- Copyright (C) 2009 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 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 compression_level = module:get_option("compression_level");
-- if not defined assume admin wants best compression
if compression_level == nil then compression_level = 9 end;


compression_level = tonumber(compression_level);
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:add_event_hook("stream-features",
		function (session, features)
			if not session.compressed 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 (data)
			local session, features = data.session, data.features;
			-- FIXME only advertise compression support when TLS layer has no compression enabled
			if not session.compressed then 
				features:add_child(compression_stream_feature);
			end
		end
);

-- S2Sout handling aka the client perspective in the S2S connection
module:hook_stanza(xmlns_stream, "features",
		function (session, stanza)
			if not session.compressed 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("info", "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", 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.deflate filter.");
		module:log("error", inflate_stream);
		return
	end
	return inflate_stream
end

-- setup compression for a stream
local function setup_compression(session, deflate_stream)
	local old_send = (session.sends2s or session.send);
	
	local new_send = function(t)
			--TODO: Better code injection in the sending process
			session.log(t)
			local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
			if status == false then
				session:close({
					condition = "undefined-condition";
					text = compressed;
					extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
				});
				module:log("warn", compressed);
				return;
			end
			session.conn:write(compressed);
		end;
	
	if session.sends2s then session.sends2s = new_send
	elseif session.send then session.send = new_send end
end

-- setup decompression for a stream
local function setup_decompression(session, inflate_stream)
	local old_data = session.data
	session.data = function(conn, data)
			local status, decompressed, eof = pcall(inflate_stream, data);
			if status == false then
				session:close({
					condition = "undefined-condition";
					text = decompressed;
					extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
				});
				module:log("warn", decompressed);
				return;
			end
			old_data(conn, decompressed);
		end;
end

-- TODO Support compression on S2S level too.
module:add_handler({"s2sout_unauthed", "s2sout"}, "compressed", xmlns_compression_protocol, 
		function(session ,stanza)
			session.log("debug", "Activating compression...")
			-- create deflate and inflate streams
			deflate_stream = get_deflate_stream(session);
			if not deflate_stream then return end
			
			inflate_stream = get_inflate_stream(session);
			if not inflate_stream then return end
			
			-- setup compression for session.w
			setup_compression(session, deflate_stream);
				
			-- setup decompression for session.data
			setup_decompression(session, inflate_stream);
			local session_reset_stream = session.reset_stream;
			session.reset_stream = function(session)
					session_reset_stream(session);
					setup_decompression(session, inflate_stream);
					return true;
				end;
			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;
		end
);

module:add_handler({"c2s_unauthed", "c2s", "s2sin_unauthed", "s2sin"}, "compress", xmlns_compression_protocol,
		function(session, stanza)
			-- fail if we are already compressed
			if session.compressed then
				local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
				(session.sends2s or session.send)(error_st);
				session.log("warn", "Tried to establish another compression layer.");
			end
			
			-- checking if the compression method is supported
			local method = stanza:child_with_name("method")[1];
			if method == "zlib" then
				session.log("info", method.." compression selected.");
				
				-- create deflate and inflate streams
				deflate_stream = get_deflate_stream(session);
				if not deflate_stream then return end
				
				inflate_stream = get_inflate_stream(session);
				if not inflate_stream then return 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);
				
				local session_reset_stream = session.reset_stream;
				session.reset_stream = function(session)
						session_reset_stream(session);
						setup_decompression(session, inflate_stream);
						return true;
					end;
				session.compressed = true;
			else
				session.log("info", method.." compression selected. But we don't support it.");
				local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
				(session.sends2s or session.send)(error_st);
			end
		end
);