mirror of
https://github.com/bjc/prosody.git
synced 2025-04-03 21:27:38 +03:00
net.stun: New library that implements STUN/TURN parsing/serialization
This commit is contained in:
Matthew Wild
parent
ab835fed13
commit
5cfe0d220d
1 changed files with 292 additions and 0 deletions
292
net/stun.lua
Normal file
292
net/stun.lua
Normal file
|
|
@ -0,0 +1,292 @@
|
|||
local base64 = require "util.encodings".base64;
|
||||
local hashes = require "util.hashes";
|
||||
local net = require "util.net";
|
||||
local random = require "util.random";
|
||||
local struct = require "util.struct";
|
||||
|
||||
--- Private helpers
|
||||
|
||||
-- XORs a string with another string
|
||||
local function sxor(x, y)
|
||||
local r = {};
|
||||
for i = 1, #x do
|
||||
r[i] = string.char(bit32.bxor(x:byte(i), y:byte(i)));
|
||||
end
|
||||
return table.concat(r);
|
||||
end
|
||||
|
||||
--- Public helpers
|
||||
|
||||
-- Following draft-uberti-behave-turn-rest-00, convert a 'secret' string
|
||||
-- into a username/password pair that can be used to auth to a TURN server
|
||||
local function get_user_pass_from_secret(secret, ttl, opt_username)
|
||||
ttl = ttl or 86400;
|
||||
local username;
|
||||
if opt_username then
|
||||
username = ("%d:%s"):format(os.time() + ttl, opt_username);
|
||||
else
|
||||
username = ("%d"):format(os.time() + ttl);
|
||||
end
|
||||
local password = base64.encode(hashes.hmac_sha1(secret, username));
|
||||
return username, password, ttl;
|
||||
end
|
||||
|
||||
-- Following RFC 8489 9.2, convert credentials to a HMAC key for signing
|
||||
local function get_long_term_auth_key(realm, username, password)
|
||||
return hashes.md5(username..":"..realm..":"..password);
|
||||
end
|
||||
|
||||
--- Packet building/parsing
|
||||
|
||||
local packet_methods = {};
|
||||
local packet_mt = { __index = packet_methods };
|
||||
|
||||
local magic_cookie = string.char(0x21, 0x12, 0xA4, 0x42);
|
||||
|
||||
local methods = {
|
||||
binding = 0x001;
|
||||
-- TURN
|
||||
allocate = 0x003;
|
||||
refresh = 0x004;
|
||||
send = 0x006;
|
||||
data = 0x007;
|
||||
create_permission = 0x008;
|
||||
channel_bind = 0x009;
|
||||
};
|
||||
local method_lookup = {};
|
||||
for name, value in pairs(methods) do
|
||||
method_lookup[name] = value;
|
||||
method_lookup[value] = name;
|
||||
end
|
||||
|
||||
local classes = {
|
||||
request = 0;
|
||||
indication = 1;
|
||||
success = 2;
|
||||
error = 3;
|
||||
};
|
||||
local class_lookup = {};
|
||||
for name, value in pairs(classes) do
|
||||
class_lookup[name] = value;
|
||||
class_lookup[value] = name;
|
||||
end
|
||||
|
||||
local attributes = {
|
||||
["mapped-address"] = 0x0001;
|
||||
["username"] = 0x0006;
|
||||
["message-integrity"] = 0x0008;
|
||||
["error-code"] = 0x0009;
|
||||
["unknown-attributes"] = 0x000A;
|
||||
["realm"] = 0x0014;
|
||||
["nonce"] = 0x0015;
|
||||
["xor-mapped-address"] = 0x0020;
|
||||
["software"] = 0x8022;
|
||||
["alternate-server"] = 0x8023;
|
||||
["fingerprint"] = 0x8028;
|
||||
["message-integrity-sha256"] = 0x001C;
|
||||
["password-algorithm"] = 0x001D;
|
||||
["userhash"] = 0x001E;
|
||||
["password-algorithms"] = 0x8002;
|
||||
["alternate-domains"] = 0x8003;
|
||||
|
||||
-- TURN
|
||||
["requested-transport"] = 0x0019;
|
||||
};
|
||||
local attribute_lookup = {};
|
||||
for name, value in pairs(attributes) do
|
||||
attribute_lookup[name] = value;
|
||||
attribute_lookup[value] = name;
|
||||
end
|
||||
|
||||
function packet_methods:serialize_header(length)
|
||||
assert(#self.transaction_id == 12, "invalid transaction id length");
|
||||
local header = struct.pack(">I2I2",
|
||||
self.type,
|
||||
length
|
||||
)..magic_cookie..self.transaction_id;
|
||||
return header;
|
||||
end
|
||||
|
||||
function packet_methods:serialize()
|
||||
local payload = table.concat(self.attributes);
|
||||
return self:serialize_header(#payload)..payload;
|
||||
end
|
||||
|
||||
function packet_methods:is_request()
|
||||
return bit32.band(self.type, 0x0110) == 0x0000;
|
||||
end
|
||||
|
||||
function packet_methods:is_indication()
|
||||
return bit32.band(self.type, 0x0110) == 0x0010;
|
||||
end
|
||||
|
||||
function packet_methods:is_success_resp()
|
||||
return bit32.band(self.type, 0x0110) == 0x0100;
|
||||
end
|
||||
|
||||
function packet_methods:is_err_resp()
|
||||
return bit32.band(self.type, 0x0110) == 0x0110;
|
||||
end
|
||||
|
||||
function packet_methods:get_method()
|
||||
local method = bit32.bor(
|
||||
bit32.rshift(bit32.band(self.type, 0x3E00), 2),
|
||||
bit32.rshift(bit32.band(self.type, 0x00E0), 1),
|
||||
bit32.band(self.type, 0x000F)
|
||||
);
|
||||
return method, method_lookup[method];
|
||||
end
|
||||
|
||||
function packet_methods:get_class()
|
||||
local class = bit32.bor(
|
||||
bit32.rshift(bit32.band(self.type, 0x0100), 7),
|
||||
bit32.rshift(bit32.band(self.type, 0x0010), 4)
|
||||
);
|
||||
return class, class_lookup[class];
|
||||
end
|
||||
|
||||
function packet_methods:set_type(method, class)
|
||||
if type(method) == "string" then
|
||||
method = assert(method_lookup[method:lower()], "unknown method: "..method);
|
||||
end
|
||||
if type(class) == "string" then
|
||||
class = assert(classes[class], "unknown class: "..class);
|
||||
end
|
||||
self.type = bit32.bor(
|
||||
bit32.lshift(bit32.band(method, 0x1F80), 2),
|
||||
bit32.lshift(bit32.band(method, 0x0070), 1),
|
||||
bit32.band(method, 0x000F),
|
||||
bit32.lshift(bit32.band(class, 0x0002), 7),
|
||||
bit32.lshift(bit32.band(class, 0x0001), 4)
|
||||
);
|
||||
end
|
||||
|
||||
local function _serialize_attribute(attr_type, value)
|
||||
local len = #value;
|
||||
local padding = string.rep("\0", (4 - len)%4);
|
||||
return struct.pack(">I2I2",
|
||||
attr_type, len
|
||||
)..value..padding;
|
||||
end
|
||||
|
||||
function packet_methods:add_attribute(attr_type, value)
|
||||
if type(attr_type) == "string" then
|
||||
attr_type = assert(attributes[attr_type], "unknown attribute: "..attr_type);
|
||||
end
|
||||
table.insert(self.attributes, _serialize_attribute(attr_type, value));
|
||||
end
|
||||
|
||||
function packet_methods:deserialize(bytes)
|
||||
local type, len, cookie = struct.unpack(">I2I2I4", bytes);
|
||||
assert(#bytes == (len + 20), "incorrect packet length");
|
||||
assert(cookie == 0x2112A442, "invalid magic cookie");
|
||||
self.type = type;
|
||||
self.transaction_id = bytes:sub(9, 20);
|
||||
self.attributes = {};
|
||||
local pos = 21;
|
||||
while pos < #bytes do
|
||||
local attr_hdr = bytes:sub(pos, pos+3);
|
||||
assert(#attr_hdr == 4, "packet truncated in attribute header");
|
||||
local attr_type, attr_len = struct.unpack(">I2I2", attr_hdr); --luacheck: ignore 211/attr_type
|
||||
if attr_len == 0 then
|
||||
table.insert(self.attributes, attr_hdr);
|
||||
pos = pos + 20;
|
||||
else
|
||||
local data = bytes:sub(pos + 4, pos + 3 + attr_len);
|
||||
assert(#data == attr_len, "packet truncated in attribute value");
|
||||
table.insert(self.attributes, attr_hdr..data);
|
||||
local n_padding = (4 - attr_len)%4;
|
||||
pos = pos + 4 + attr_len + n_padding;
|
||||
end
|
||||
end
|
||||
return self;
|
||||
end
|
||||
|
||||
function packet_methods:get_attribute(attr_type)
|
||||
if type(attr_type) == "string" then
|
||||
attr_type = assert(attribute_lookup[attr_type:lower()], "unknown attribute: "..attr_type);
|
||||
end
|
||||
for _, attribute in ipairs(self.attributes) do
|
||||
if struct.unpack(">I2", attribute) == attr_type then
|
||||
return attribute:sub(5);
|
||||
end
|
||||
end
|
||||
end
|
||||
|
||||
local addr_families = { "IPv4", "IPv6" };
|
||||
function packet_methods:get_mapped_address()
|
||||
local data = self:get_attribute("mapped-address");
|
||||
if not data then return; end
|
||||
local family, port = struct.unpack("x>BI2", data);
|
||||
local addr = data:sub(5);
|
||||
return {
|
||||
family = addr_families[family] or "unknown";
|
||||
port = port;
|
||||
address = net.ntop(addr);
|
||||
};
|
||||
end
|
||||
|
||||
function packet_methods:get_xor_mapped_address()
|
||||
local data = self:get_attribute("xor-mapped-address");
|
||||
if not data then return; end
|
||||
local family, port = struct.unpack("x>BI2", data);
|
||||
local addr = sxor(data:sub(5), magic_cookie..self.transaction_id);
|
||||
return {
|
||||
family = addr_families[family] or "unknown";
|
||||
port = bit32.bxor(port, 0x2112);
|
||||
address = net.ntop(addr);
|
||||
address_raw = data:sub(5);
|
||||
};
|
||||
end
|
||||
|
||||
function packet_methods:add_message_integrity(key)
|
||||
-- Add attribute with a dummy value so we can artificially increase
|
||||
-- the packet 'length'
|
||||
self:add_attribute("message-integrity", string.rep("\0", 20));
|
||||
-- Get the packet data, minus the message-integrity attribute itself
|
||||
local pkt = self:serialize():sub(1, -25);
|
||||
local hash = hashes.hmac_sha1(key, pkt, false);
|
||||
self.attributes[#self.attributes] = nil;
|
||||
assert(#hash == 20, "invalid hash length");
|
||||
self:add_attribute("message-integrity", hash);
|
||||
end
|
||||
|
||||
do
|
||||
local transports = {
|
||||
udp = 0x11;
|
||||
};
|
||||
function packet_methods:add_requested_transport(transport)
|
||||
local transport_code = transports[transport];
|
||||
assert(transport_code, "unsupported transport: "..tostring(transport));
|
||||
self:add_attribute("requested-transport", string.char(
|
||||
transport_code, 0x00, 0x00, 0x00
|
||||
));
|
||||
end
|
||||
end
|
||||
|
||||
function packet_methods:get_error()
|
||||
local err_attr = self:get_attribute("error-code");
|
||||
if not err_attr then
|
||||
return nil;
|
||||
end
|
||||
local number = err_attr:byte(4);
|
||||
local class = bit32.band(0x07, err_attr:byte(3));
|
||||
local msg = err_attr:sub(5);
|
||||
return (class*100)+number, msg;
|
||||
end
|
||||
|
||||
local function new_packet(method, class)
|
||||
local p = setmetatable({
|
||||
transaction_id = random.bytes(12);
|
||||
length = 0;
|
||||
attributes = {};
|
||||
}, packet_mt);
|
||||
p:set_type(method or "binding", class or "request");
|
||||
return p;
|
||||
end
|
||||
|
||||
return {
|
||||
new_packet = new_packet;
|
||||
get_user_pass_from_secret = get_user_pass_from_secret;
|
||||
get_long_term_auth_key = get_long_term_auth_key;
|
||||
};
|
||||
Loading…
Add table
Add a link
Reference in a new issue