mumble-web-proxy/src/connection.rs
2019-02-09 10:40:38 +01:00

623 lines
25 KiB
Rust

use futures::stream;
use futures::{Future, Sink, Stream};
use libnice::ice;
use mumble_protocol::control::msgs;
use mumble_protocol::control::ControlPacket;
use mumble_protocol::voice::VoicePacket;
use mumble_protocol::voice::VoicePacketPayload;
use mumble_protocol::Clientbound;
use mumble_protocol::Serverbound;
use openssl::asn1::Asn1Time;
use openssl::hash::MessageDigest;
use openssl::pkey::{PKey, Private};
use openssl::rsa::Rsa;
use openssl::ssl::{SslAcceptor, SslAcceptorBuilder, SslMethod};
use openssl::x509::X509;
use rtp::rfc3550::{
RtcpCompoundPacket, RtcpPacket, RtcpPacketReader, RtcpPacketWriter, RtpFixedHeader, RtpPacket,
RtpPacketReader, RtpPacketWriter,
};
use rtp::rfc5761::{MuxPacketReader, MuxPacketWriter, MuxedPacket};
use rtp::rfc5764::{DtlsSrtp, DtlsSrtpHandshakeResult};
use rtp::traits::{ReadPacket, WritePacket};
use std::collections::BTreeMap;
use std::ffi::CString;
use std::net::IpAddr;
use std::time::{Duration, Instant};
use tokio::io;
use tokio::prelude::*;
use tokio::timer::Delay;
use webrtc_sdp::attribute_type::SdpAttribute;
use error::Error;
use utils::EitherS;
use Config;
type SessionId = u32;
struct User {
session: u32, // mumble session id
ssrc: u32, // ssrc id
active: bool, // whether the user is currently transmitting audio
timeout: Option<Delay>, // assume end of transmission if silent until then
start_voice_seq_num: u64,
highest_voice_seq_num: u64,
rtp_seq_num_offset: u32, // u32 because we also derive the timestamp from it
}
impl User {
fn set_inactive(&mut self) -> impl Stream<Item = Frame, Error = Error> {
self.timeout = None;
if self.active {
self.active = false;
self.rtp_seq_num_offset = self
.rtp_seq_num_offset
.wrapping_add((self.highest_voice_seq_num - self.start_voice_seq_num) as u32 + 1);
self.start_voice_seq_num = 0;
self.highest_voice_seq_num = 0;
let mut msg = msgs::TalkingState::new();
msg.set_session(self.session);
EitherS::A(stream::once(Ok(Frame::Client(msg.into()))))
} else {
EitherS::B(stream::empty())
}
}
fn set_active(&mut self, target: u8) -> impl Stream<Item = Frame, Error = Error> {
let when = Instant::now() + Duration::from_millis(400);
self.timeout = Some(Delay::new(when));
if self.active {
EitherS::A(stream::empty())
} else {
self.active = true;
let mut msg = msgs::TalkingState::new();
msg.set_session(self.session);
msg.set_target(target.into());
EitherS::B(stream::once(Ok(Frame::Client(msg.into()))))
}
}
}
pub struct Connection {
config: Config,
inbound_client: Box<Stream<Item = ControlPacket<Serverbound>, Error = Error>>,
outbound_client: Box<Sink<SinkItem = ControlPacket<Clientbound>, SinkError = Error>>,
inbound_server: Box<Stream<Item = ControlPacket<Clientbound>, Error = Error>>,
outbound_server: Box<Sink<SinkItem = ControlPacket<Serverbound>, SinkError = Error>>,
next_clientbound_frame: Option<ControlPacket<Clientbound>>,
next_serverbound_frame: Option<ControlPacket<Serverbound>>,
next_rtp_frame: Option<Vec<u8>>,
stream_to_be_sent: Option<Box<Stream<Item = Frame, Error = Error>>>,
ice: Option<(ice::Agent, ice::Stream)>,
dtls_srtp_future: Option<DtlsSrtpHandshakeResult<ice::StreamComponent, SslAcceptorBuilder>>,
dtls_srtp: Option<DtlsSrtp<ice::StreamComponent, SslAcceptorBuilder>>,
dtls_key: PKey<Private>,
dtls_cert: X509,
rtp_reader: MuxPacketReader<RtpPacketReader, RtcpPacketReader>,
rtp_writer: MuxPacketWriter<RtpPacketWriter, RtcpPacketWriter>,
target: Option<u8>, // only if client is talking
next_ssrc: u32,
free_ssrcs: Vec<u32>,
sessions: BTreeMap<SessionId, User>,
}
impl Connection {
pub fn new<CSi, CSt, SSi, SSt>(
config: Config,
client_sink: CSi,
client_stream: CSt,
server_sink: SSi,
server_stream: SSt,
) -> Self
where
CSi: Sink<SinkItem = ControlPacket<Clientbound>, SinkError = Error> + 'static,
CSt: Stream<Item = ControlPacket<Serverbound>, Error = Error> + 'static,
SSi: Sink<SinkItem = ControlPacket<Serverbound>, SinkError = Error> + 'static,
SSt: Stream<Item = ControlPacket<Clientbound>, Error = Error> + 'static,
{
let rsa = Rsa::generate(2048).unwrap();
let key = PKey::from_rsa(rsa).unwrap();
let mut cert_builder = X509::builder().unwrap();
cert_builder
.set_not_after(&Asn1Time::days_from_now(1).unwrap())
.unwrap();
cert_builder
.set_not_before(&Asn1Time::days_from_now(0).unwrap())
.unwrap();
cert_builder.set_pubkey(&key).unwrap();
cert_builder.sign(&key, MessageDigest::sha256()).unwrap();
let cert = cert_builder.build();
Self {
config,
inbound_client: Box::new(client_stream),
outbound_client: Box::new(client_sink),
inbound_server: Box::new(server_stream),
outbound_server: Box::new(server_sink),
next_clientbound_frame: None,
next_serverbound_frame: None,
next_rtp_frame: None,
stream_to_be_sent: None,
ice: None,
dtls_srtp_future: None,
dtls_srtp: None,
dtls_key: key,
dtls_cert: cert,
rtp_reader: MuxPacketReader::new(RtpPacketReader, RtcpPacketReader),
rtp_writer: MuxPacketWriter::new(RtpPacketWriter, RtcpPacketWriter),
target: None,
next_ssrc: 1,
free_ssrcs: Vec::new(),
sessions: BTreeMap::new(),
}
}
fn allocate_ssrc(&mut self, session_id: SessionId) -> &mut User {
let ssrc = self.free_ssrcs.pop().unwrap_or_else(|| {
let ssrc = self.next_ssrc;
self.next_ssrc += 1;
if let Some(ref mut dtls_srtp) = self.dtls_srtp {
dtls_srtp.add_incoming_unknown_ssrcs(1);
dtls_srtp.add_outgoing_unknown_ssrcs(1);
}
ssrc
});
let user = User {
session: session_id,
ssrc,
active: false,
timeout: None,
start_voice_seq_num: 0,
highest_voice_seq_num: 0,
rtp_seq_num_offset: 0,
};
self.sessions.insert(session_id, user);
self.sessions.get_mut(&session_id).unwrap()
}
fn free_ssrc(&mut self, session_id: SessionId) {
if let Some(user) = self.sessions.remove(&session_id) {
self.free_ssrcs.push(user.ssrc)
}
}
fn setup_ice(&mut self) -> impl Stream<Item = Frame, Error = Error> {
// Setup ICE agent
let mut agent = ice::Agent::new_rfc5245();
agent.set_software("mumble-web-proxy");
// Setup ICE stream
let mut stream = match {
let mut builder = agent.stream_builder(1);
if self.config.min_port != 1 || self.config.max_port != u16::max_value() {
builder.set_port_range(self.config.min_port, self.config.max_port);
}
builder.build()
} {
Ok(stream) => stream,
Err(err) => {
return stream::once(Err(io::Error::new(io::ErrorKind::Other, err).into()));
}
};
let component = stream.take_components().pop().expect("one component");
// Send WebRTC details to the client
let mut msg = msgs::WebRTC::new();
msg.set_dtls_fingerprint(
self.dtls_cert
.digest(MessageDigest::sha256())
.unwrap()
.iter()
.map(|byte| format!("{:02X}", byte))
.collect::<Vec<_>>()
.join(":"),
);
msg.set_ice_pwd(stream.get_local_pwd().to_owned());
msg.set_ice_ufrag(stream.get_local_ufrag().to_owned());
// Store ice agent and stream for later use
self.ice = Some((agent, stream));
// Prepare to accept the DTLS connection
let mut acceptor = SslAcceptor::mozilla_modern(SslMethod::dtls()).unwrap();
acceptor.set_certificate(&self.dtls_cert).unwrap();
acceptor.set_private_key(&self.dtls_key).unwrap();
// FIXME: verify remote fingerprint
self.dtls_srtp_future = Some(DtlsSrtp::handshake(component, acceptor));
stream::once(Ok(Frame::Client(msg.into())))
}
fn handle_voice_packet(
&mut self,
packet: VoicePacket<Clientbound>,
) -> impl Stream<Item = Frame, Error = Error> {
let (target, session_id, seq_num, opus_data, last_bit) = match packet {
VoicePacket::Audio {
target,
session_id,
seq_num,
payload: VoicePacketPayload::Opus(data, last_bit),
..
} => (target, session_id, seq_num, data, last_bit),
_ => return EitherS::B(stream::empty()),
};
// NOTE: the mumble packet id increases by 1 per 10ms of audio contained
// whereas rtp seq_num should increase by 1 per packet, regardless of audio,
// but firefox seems to be just fine if we skip over rtp seq_nums.
// NOTE: we rely on the srtp layer to prevent two-time-pads and by doing so,
// allow for (reasonable) jitter of incoming voice packets.
let user = match self.sessions.get_mut(&(session_id as u32)) {
Some(s) => s,
None => return EitherS::B(stream::empty()),
};
let rtp_ssrc = user.ssrc;
let mut first_in_transmission = if user.active {
false
} else {
user.start_voice_seq_num = seq_num;
user.highest_voice_seq_num = seq_num;
true
};
let offset = seq_num - user.start_voice_seq_num;
let mut rtp_seq_num = user.rtp_seq_num_offset + offset as u32;
let activity_stream = if last_bit {
if seq_num <= user.highest_voice_seq_num {
// Horribly delayed end packet from a previous stream, just drop it
// (or single packet stream which would be inaudible anyway)
return EitherS::B(stream::empty());
}
// this is the last packet of this voice transmission -> reset counters
// doing that will effectively trash any delayed packets but that's just
// a flaw in the mumble protocol and there's nothing we can do about it.
EitherS::B(user.set_inactive())
} else {
EitherS::A(
if seq_num == user.highest_voice_seq_num && seq_num != user.start_voice_seq_num {
// re-transmission, drop it
return EitherS::B(stream::empty());
} else if seq_num >= user.highest_voice_seq_num
&& seq_num < user.highest_voice_seq_num + 100
{
// probably same voice transmission (also not too far in the future)
user.highest_voice_seq_num = seq_num;
EitherS::A(user.set_active(target))
} else if seq_num < user.highest_voice_seq_num
&& seq_num + 100 > user.highest_voice_seq_num
{
// slightly delayed but probably same voice transmission
EitherS::A(user.set_active(target))
} else {
// Either significant jitter (>2s) or we missed the end of the last
// transmission. Since >2s jitter will break opus horribly anyway,
// we assume the latter and start a new transmission
let stream = user.set_inactive();
first_in_transmission = true;
user.start_voice_seq_num = seq_num;
user.highest_voice_seq_num = seq_num;
rtp_seq_num = user.rtp_seq_num_offset;
EitherS::B(stream.chain(user.set_active(target)))
},
)
};
let rtp_time = 480 * rtp_seq_num;
let rtp = RtpPacket {
header: RtpFixedHeader {
padding: false,
marker: first_in_transmission,
payload_type: 97,
seq_num: rtp_seq_num as u16,
timestamp: rtp_time as u32,
ssrc: rtp_ssrc,
csrc_list: Vec::new(),
extension: None,
},
payload: opus_data.to_vec(),
padding: Vec::new(),
};
let frame = Frame::Rtp(MuxedPacket::Rtp(rtp));
EitherS::A(activity_stream.chain(stream::once(Ok(frame))))
}
fn process_packet_from_server(
&mut self,
packet: ControlPacket<Clientbound>,
) -> impl Stream<Item = Frame, Error = Error> {
match packet {
ControlPacket::UDPTunnel(voice) => EitherS::A(self.handle_voice_packet(*voice)),
ControlPacket::UserState(mut message) => {
let session_id = message.get_session();
if !self.sessions.contains_key(&session_id) {
let user = self.allocate_ssrc(session_id);
message.set_ssrc(user.ssrc);
}
EitherS::B(stream::once(Ok(Frame::Client((*message).into()))))
}
ControlPacket::UserRemove(message) => {
self.free_ssrc(message.get_session());
EitherS::B(stream::once(Ok(Frame::Client((*message).into()))))
}
other => EitherS::B(stream::once(Ok(Frame::Client(other)))),
}
}
fn process_packet_from_client(
&mut self,
packet: ControlPacket<Serverbound>,
) -> Box<Stream<Item = Frame, Error = Error>> {
match packet {
ControlPacket::Authenticate(mut message) => {
println!("MSG Authenticate: {:?}", message);
if message.get_webrtc() {
// strip webrtc support from the connection (we will be providing it)
message.clear_webrtc();
// and make sure opus is marked as supported
message.set_opus(true);
let stream = self.setup_ice();
Box::new(stream::once(Ok(Frame::Server((*message).into()))).chain(stream))
} else {
Box::new(stream::once(Ok(Frame::Server((*message).into()))))
}
}
ControlPacket::WebRTC(mut message) => {
println!("Got WebRTC: {:?}", message);
if let Some((_, stream)) = &mut self.ice {
if let (Ok(ufrag), Ok(pwd)) = (
CString::new(message.take_ice_ufrag()),
CString::new(message.take_ice_pwd()),
) {
stream.set_remote_credentials(ufrag, pwd);
}
// FIXME trigger ICE-restart if required
// FIXME store and use remote dtls fingerprint
}
Box::new(stream::empty())
}
ControlPacket::IceCandidate(mut message) => {
let candidate = message.take_content();
println!("Got ice candidate: {:?}", candidate);
if let Some((_, stream)) = &mut self.ice {
match format!("candidate:{}", candidate).parse() {
Ok(SdpAttribute::Candidate(candidate)) => {
stream.add_remote_candidate(candidate)
}
Ok(_) => unreachable!(),
Err(err) => {
return Box::new(stream::once(Err(io::Error::new(
io::ErrorKind::Other,
format!("Error parsing ICE candidate: {}", err),
)
.into())));
}
}
}
Box::new(stream::empty())
}
ControlPacket::TalkingState(message) => {
self.target = if message.has_target() {
Some(message.get_target() as u8)
} else {
None
};
Box::new(stream::empty())
}
other => Box::new(stream::once(Ok(Frame::Server(other)))),
}
}
fn process_rtp_packet(&mut self, buf: &[u8]) -> impl Stream<Item = Frame, Error = Error> {
stream::iter_result(match self.rtp_reader.read_packet(&mut &buf[..]) {
Ok(MuxedPacket::Rtp(rtp)) => {
if let Some(target) = self.target {
// FIXME derive mumble seq_num from rtp timestamp to properly handle
// packet reordering and loss (done). But maybe keep it low?
let seq_num = rtp.header.timestamp / 480;
let voice_packet = VoicePacket::Audio {
_dst: std::marker::PhantomData::<Serverbound>,
target,
session_id: (),
seq_num: seq_num.into(),
payload: VoicePacketPayload::Opus(rtp.payload.into(), false),
position_info: None,
};
Some(Ok(Frame::Server(voice_packet.into())))
} else {
None
}
}
Ok(MuxedPacket::Rtcp(_rtcp)) => None,
Err(_err) => None, // FIXME maybe not silently drop the error?
})
}
}
impl Future for Connection {
type Item = ();
type Error = Error;
fn poll(&mut self) -> Poll<(), Error> {
'poll: loop {
if let Some((agent, _)) = &mut self.ice {
agent.poll()?;
}
// If there's a frame pending to be sent, sent it before everything else
if let Some(frame) = self.next_serverbound_frame.take() {
match self.outbound_server.start_send(frame)? {
AsyncSink::NotReady(frame) => {
self.next_serverbound_frame = Some(frame);
return Ok(Async::NotReady);
}
AsyncSink::Ready => {}
}
}
if let Some(frame) = self.next_clientbound_frame.take() {
match self.outbound_client.start_send(frame)? {
AsyncSink::NotReady(frame) => {
self.next_clientbound_frame = Some(frame);
return Ok(Async::NotReady);
}
AsyncSink::Ready => {}
}
}
if let Some(frame) = self.next_rtp_frame.take() {
if let Some(ref mut dtls_srtp) = self.dtls_srtp {
match dtls_srtp.start_send(frame)? {
AsyncSink::NotReady(frame) => {
self.next_rtp_frame = Some(frame);
return Ok(Async::NotReady);
}
AsyncSink::Ready => {}
}
} else {
// RTP not yet setup, just drop the frame
}
}
// Send out all pending frames
if self.stream_to_be_sent.is_some() {
match self.stream_to_be_sent.as_mut().unwrap().poll()? {
Async::NotReady => return Ok(Async::NotReady),
Async::Ready(Some(frame)) => {
match frame {
Frame::Server(frame) => self.next_serverbound_frame = Some(frame),
Frame::Client(frame) => self.next_clientbound_frame = Some(frame),
Frame::Rtp(frame) => {
let mut buf = Vec::new();
self.rtp_writer.write_packet(&mut buf, &frame)?;
self.next_rtp_frame = Some(buf)
}
}
continue 'poll;
}
Async::Ready(None) => {
self.stream_to_be_sent = None;
}
}
}
// All frames have been sent (or queued), flush any buffers in the output path
self.outbound_client.poll_complete()?;
self.outbound_server.poll_complete()?;
if let Some(ref mut dtls_srtp) = self.dtls_srtp {
dtls_srtp.poll_complete()?;
}
// Check/register voice timeouts
// Note that this must be ran if any new sessions are added or timeouts are
// modified as otherwise we may be blocking on IO and won't get notified of
// timeouts. In particular, this means that it has to always be called if
// we suspect that we may be blocking on inbound IO (outbound is less critical
// since any action taken as a result of timeouts will have to wait for it
// anyway), hence this being positioned above the code for incoming packets below.
// (same applies to the other futures directly below it)
for session in self.sessions.values_mut() {
if let Async::Ready(Some(())) = session.timeout.poll()? {
let stream = session.set_inactive();
self.stream_to_be_sent = Some(Box::new(stream));
continue 'poll;
}
}
// Poll ice stream for new candidates
if let Some((_, stream)) = &mut self.ice {
if let Async::Ready(Some(mut candidate)) = stream.poll()? {
println!("Local ice candidate: {}", candidate.to_string());
// Map to public addresses (if configured)
let config = &self.config;
match (&mut candidate.address, config.public_v4, config.public_v6) {
(IpAddr::V4(addr), Some(public), _) => {
*addr = public;
}
(IpAddr::V6(addr), _, Some(public)) => {
*addr = public;
}
_ => {} // non configured
};
// Got a new candidate, send it to the client
let mut msg = msgs::IceCandidate::new();
msg.set_content(format!("candidate:{}", candidate.to_string()));
let frame = Frame::Client(msg.into());
self.stream_to_be_sent = Some(Box::new(stream::once(Ok(frame))));
continue 'poll;
}
}
// Poll dtls_srtp future if required
if let Async::Ready(Some(mut dtls_srtp)) = self.dtls_srtp_future.poll()? {
self.dtls_srtp_future = None;
println!("DTLS-SRTP connection established.");
dtls_srtp.add_incoming_unknown_ssrcs(self.next_ssrc as usize);
dtls_srtp.add_outgoing_unknown_ssrcs(self.next_ssrc as usize);
self.dtls_srtp = Some(dtls_srtp);
}
// Finally check for incoming packets
match self.inbound_server.poll()? {
Async::NotReady => {}
Async::Ready(Some(frame)) => {
let stream = self.process_packet_from_server(frame);
self.stream_to_be_sent = Some(Box::new(stream));
continue 'poll;
}
Async::Ready(None) => return Ok(Async::Ready(())),
}
match self.inbound_client.poll()? {
Async::NotReady => {}
Async::Ready(Some(frame)) => {
let stream = self.process_packet_from_client(frame);
self.stream_to_be_sent = Some(Box::new(stream));
continue 'poll;
}
Async::Ready(None) => return Ok(Async::Ready(())),
}
if self.dtls_srtp.is_some() {
match self.dtls_srtp.as_mut().unwrap().poll()? {
Async::NotReady => {}
Async::Ready(Some(frame)) => {
let stream = self.process_rtp_packet(&frame);
self.stream_to_be_sent = Some(Box::new(stream));
continue 'poll;
}
Async::Ready(None) => return Ok(Async::Ready(())),
}
}
return Ok(Async::NotReady);
}
}
}
#[derive(Clone)]
enum Frame {
Server(ControlPacket<Serverbound>),
Client(ControlPacket<Clientbound>),
Rtp(MuxedPacket<RtpPacket, RtcpCompoundPacket<RtcpPacket>>),
}