--- a/mod_websocket/mod_websocket.lua Fri Oct 05 05:49:22 2012 +0500
+++ b/mod_websocket/mod_websocket.lua Fri Oct 05 16:57:34 2012 +0200
@@ -47,6 +47,8 @@
local counter = 0;
local tmp_byte;
+ if #frame < 2 then return; end
+
tmp_byte = string.byte(frame, pos);
result.FIN = band(tmp_byte, 0x80) > 0;
result.RSV1 = band(tmp_byte, 0x40) > 0;
@@ -67,11 +69,15 @@
result.length = 0;
end
+ if #frame < (2 + length_bytes) then return; end
+
for i = 1, length_bytes do
pos = pos + 1;
result.length = result.length * 256 + string.byte(frame, pos);
end
+ if #frame < (2 + length_bytes + (result.MASK and 4 or 0) + result.length) then return; end
+
if result.MASK then
result.key = {string.byte(frame, pos+1), string.byte(frame, pos+2),
string.byte(frame, pos+3), string.byte(frame, pos+4)}
@@ -86,16 +92,17 @@
result.data = frame:sub(pos + 1, pos + result.length);
end
- return result;
+ return result, 2 + length_bytes + (result.MASK and 4 or 0) + result.length;
end
local function build_frame(desc)
local length;
local result = "";
+ local data = desc.data or "";
result = result .. string.char(0x80 * (desc.FIN and 1 or 0) + desc.opcode);
- length = #desc.data;
+ length = #data;
if length <= 125 then -- 7-bit length
result = result .. string.char(length);
elseif length <= 0xFFFF then -- 2-byte length
@@ -108,7 +115,7 @@
end
end
- result = result .. desc.data;
+ result = result .. data;
return result;
end
@@ -296,26 +303,71 @@
session.stream:reset();
end
+ local function websocket_close(code, message)
+ local data = string.char(code/0x100) .. string.char(code%0x100) .. message;
+ conn:write(build_frame({opcode = 0x8, FIN = true, data = data}));
+ conn:close();
+ end
+
local filter = session.filter;
- local buffer = "";
- function session.data(data)
- local frame = parse_frame(data);
+ local dataBuffer;
+ local function handle_frame(frame)
+ module:log("debug", "Websocket received: %s (%i bytes)", frame.data, #frame.data);
+
+ -- Error cases
+ if frame.RSV1 or frame.RSV2 or frame.RSV3 then -- Reserved bits non zero
+ websocket_close(1002, "Reserved bits not zero");
+ return false;
+ end
+
+ if frame.opcode >= 0x8 and frame.length > 125 then -- Control frame with too much payload
+ websocket_close(1002, "Payload too large");
+ return false;
+ end
+
+ if frame.opcode >= 0x8 and not frame.FIN then -- Fragmented control frame
+ websocket_close(1002, "Fragmented control frame");
+ return false;
+ end
- module:log("debug", "Websocket received: %s (%i bytes)", frame.data, #frame.data);
- if frame.opcode == 0x0 or frame.opcode == 0x1 then -- Text or continuation frame
- buffer = buffer .. frame.data;
+ if (frame.opcode > 0x2 and frame.opcode < 0x8) or (frame.opcode > 0xA) then
+ websocket_close(1002, "Reserved opcode");
+ return false;
+ end
+
+ if frame.opcode == 0x0 and not dataBuffer then
+ websocket_close(1002, "Unexpected continuation frame");
+ return false;
+ end
+
+ if (frame.opcode == 0x1 or frame.opcode == 0x2) and dataBuffer then
+ websocket_close(1002, "Continuation frame expected");
+ return false;
+ end
+
+ -- Valid cases
+ if frame.opcode == 0x0 then -- Continuation frame
+ dataBuffer = dataBuffer .. frame.data;
+ elseif frame.opcode == 0x1 then -- Text frame
+ dataBuffer = frame.data;
+ elseif frame.opcode == 0x2 then -- Binary frame
+ websocket_close(1003, "Only text frames are supported");
+ return false;
+ elseif frame.opcode == 0x8 then -- Close request
+ websocket_close(1000, "Goodbye");
+ return false;
elseif frame.opcode == 0x9 then -- Ping frame
frame.opcode = 0xA;
conn:write(build_frame(frame));
- return;
+ return true;
else
log("warn", "Received frame with unsupported opcode %i", frame.opcode);
- return;
+ return true;
end
if frame.FIN then
- data = buffer;
- buffer = "";
+ data = dataBuffer;
+ dataBuffer = nil;
-- COMPAT: Current client implementations send a self-closing <stream:stream>
if self_closing_stream then
@@ -330,6 +382,19 @@
session:close("not-well-formed");
end
end
+ return true;
+ end
+
+ local frameBuffer = "";
+ function session.data(data)
+ frameBuffer = frameBuffer .. data;
+ local frame, length = parse_frame(frameBuffer);
+
+ while frame do
+ frameBuffer = frameBuffer:sub(length + 1);
+ if not handle_frame(frame) then return; end
+ frame, length = parse_frame(frameBuffer);
+ end
end
function session.send(s)
@@ -381,6 +446,8 @@
</body></html>]];
end
+ -- TODO: Handle requested subprotocols
+
response.conn:setlistener(listener);
response.status = "101 Switching Protocols";
response.headers.Upgrade = "websocket";