Merge pull request #659 from Blightmud/telnet_charset_negotiation

Introduces CHARSET negotiation (RFC-2066)

resources/lua/telnet_charset.lua

@@ -0,0 +1,74 @@
+local PROTOCOL = 42
+local REQUEST = 1
+local ACCEPTED = 2
+local REJECTED = 3
+
+local ACCEPTED_ENCODINGS = {
+ "UTF-8",
+ "ASCII",
+ "US-ASCII",
+}
+
+local unpack = table.unpack
+local lower = string.lower
+
+core.enable_protocol(PROTOCOL)
+
+local function split(istr, sep)
+ if sep == nil then
+ sep = "%s"
+ end
+ local t={}
+ for str in string.gmatch(istr, "([^" .. sep .. "]+)") do
+ table.insert(t, str)
+ end
+ return t
+end
+
+local function string_to_bytes(str)
+ local values = {}
+ for i, v in utf8.codes(str) do
+ values[i] = v
+ end
+ return values
+end
+
+local function send_accept(option)
+ blight.debug("TELCHR[sending]: ACCEPTED " .. option)
+ local payload = string_to_bytes(option)
+ table.insert(payload, 1, ACCEPTED)
+ core.subneg_send(PROTOCOL, payload)
+end
+
+local function send_reject()
+ blight.debug("TELCHR[sending]: REJECTED")
+ core.subneg_send(PROTOCOL, { REJECTED })
+end
+
+core.subneg_recv(function (proto, recv)
+ if proto ~= PROTOCOL or recv[1] ~= REQUEST then
+ return
+ end
+
+ table.remove(recv, 1) -- Remove the negotiation type
+ local sep = utf8.char(recv[1]) -- Extract separator
+ table.remove(recv, 1) -- Remove first separator
+ local options = utf8.char(unpack(recv))
+ blight.debug("TELCHR[received]: " .. options)
+
+ for _,opt in ipairs(split(options, sep)) do
+ for _,accepted in ipairs(ACCEPTED_ENCODINGS) do
+ if lower(opt) == lower(accepted) then
+ send_accept(opt)
+ return
+ end
+ end
+ end
+ send_reject()
+end)
+
+core.on_protocol_enabled(function (proto)
+ if proto == PROTOCOL then
+ mud.add_tag("TELCHR")
+ end
+end)

src/lua/lua_script.rs

@@ -122,6 +122,9 @@ fn create_default_lua_state(
  state
  .load(include_str!("../../resources/lua/plugins.lua"))
  .exec()?;
+ state
+ .load(include_str!("../../resources/lua/telnet_charset.lua"))
+ .exec()?;
 
  let lua_gmcp = state
  .load(include_str!("../../resources/lua/gmcp.lua"))