plugins/mod_compression.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2009 Tobias Markmann
   3 --
   4 -- This project is MIT/X11 licensed. Please see the
   5 -- COPYING file in the source package for more information.
   6 --
   7
   8 local st = require "util.stanza";
   9 local zlib = require "zlib";
  10 local pcall = pcall;
  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();
  15
  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;
  19
  20
  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.");
  25         return;
  26 end
  27
  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);
  33                         end
  34                 end
  35 );
  36
  37 module:hook("s2s-stream-features",
  38                 function (data)
  39                         local session, features = data.session, data.features;
  40                         -- FIXME only advertise compression support when TLS layer has no compression enabled
  41                         features:add_child(compression_stream_feature);
  42                 end
  43 );
  44
  45 -- S2Sout handling aka the client perspective in the S2S connection
  46 module:hook_stanza(xmlns_stream, "features",
  47                 function (session, stanza)
  48                         if not session.compressed then
  49                                 module:log("debug", "FEATURES: "..stanza:pretty_print())
  50                                 -- does remote server support compression?
  51                                 local comp_st = stanza:child_with_name("compression");
  52                                 if comp_st then
  53                                         -- do we support the mechanism
  54                                         for a in comp_st:children() do
  55                                                 local algorithm = a[1]
  56                                                 if algorithm == "zlib" then
  57                                                         session.sends2s(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib"))
  58                                                         session.log("info", "Enabled compression using zlib.")
  59                                                         return true;
  60                                                 end
  61                                         end
  62                                         session.log("debug", "Remote server supports no compression algorithm we support.")
  63                                 end
  64                         end
  65                 end
  66 , 250);
  67
  68 -- TODO Support compression on S2S level too.
  69 module:add_handler({"s2sout_unauthed", "s2sout"}, "compressed", xmlns_compression_protocol,
  70                 function(session ,stanza)
  71                         session.log("debug", "Activating compression...")
  72                 end
  73 );
  74
  75 module:add_handler({"c2s_unauthed", "c2s", "s2sin_unauthed", "s2sin"}, "compress", xmlns_compression_protocol,
  76                 function(session, stanza)
  77                         -- fail if we are already compressed
  78                         if session.compressed then
  79                                 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
  80                                 session.send(error_st);
  81                                 session.log("warn", "Tried to establish another compression layer.");
  82                         end
  83
  84                         -- checking if the compression method is supported
  85                         local method = stanza:child_with_name("method")[1];
  86                         if method == "zlib" then
  87                                 session.log("info", method.." compression selected.");
  88                                 (session.sends2s or session.send)(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
  89                                 session:reset_stream();
  90
  91                                 -- create deflate and inflate streams
  92                                 local status, deflate_stream = pcall(zlib.deflate, compression_level);
  93                                 if status == false then
  94                                         local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
  95                                         (session.sends2s or session.send)(error_st);
  96                                         session.log("error", "Failed to create zlib.deflate filter.");
  97                                         module:log("error", deflate_stream);
  98                                         return
  99                                 end
 100
 101                                 local status, inflate_stream = pcall(zlib.inflate);
 102                                 if status == false then
 103                                         local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
 104                                         (session.sends2s or session.send)(error_st);
 105                                         session.log("error", "Failed to create zlib.deflate filter.");
 106                                         module:log("error", inflate_stream);
 107                                         return
 108                                 end
 109
 110                                 -- setup compression for session.w
 111                                 local function setup_compression(session)
 112                                         local old_send = session.send;
 113
 114                                         session.send = function(t)
 115                                                         local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
 116                                                         if status == false then
 117                                                                 session:close({
 118                                                                         condition = "undefined-condition";
 119                                                                         text = compressed;
 120                                                                         extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
 121                                                                 });
 122                                                                 module:log("warn", compressed);
 123                                                                 return;
 124                                                         end
 125                                                         old_send(compressed);
 126                                                 end;
 127                                 end
 128                                 setup_compression(session);
 129
 130                                 -- setup decompression for session.data
 131                                 local function setup_decompression(session)
 132                                         local old_data = session.data
 133                                         session.data = function(conn, data)
 134                                                         local status, decompressed, eof = pcall(inflate_stream, data);
 135                                                         if status == false then
 136                                                                 session:close({
 137                                                                         condition = "undefined-condition";
 138                                                                         text = decompressed;
 139                                                                         extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
 140                                                                 });
 141                                                                 module:log("warn", decompressed);
 142                                                                 return;
 143                                                         end
 144                                                         old_data(conn, decompressed);
 145                                                 end;
 146                                 end
 147                                 setup_decompression(session);
 148
 149                                 local session_reset_stream = session.reset_stream;
 150                                 session.reset_stream = function(session)
 151                                                 session_reset_stream(session);
 152                                                 setup_decompression(session);
 153                                                 return true;
 154                                         end;
 155                                 session.compressed = true;
 156                         else
 157                                 session.log("info", method.." compression selected. But we don't support it.");
 158                                 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
 159                                 (session.sends2s or session.send)(error_st);
 160                         end
 161                 end
 162 );
 163