631 lines
15 KiB
Rust
631 lines
15 KiB
Rust
use std::{
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error::Error,
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collections::*,
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convert::Infallible,
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iter::FromIterator,
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net::SocketAddr,
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sync::{
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Arc,
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},
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time::Duration,
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};
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use dashmap::DashMap;
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use futures::{
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FutureExt,
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stream::StreamExt,
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};
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use handlebars::Handlebars;
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use hyper::{
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Body,
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Method,
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Request,
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Response,
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Server,
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StatusCode,
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};
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use hyper::service::{make_service_fn, service_fn};
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use serde::{
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Deserialize,
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Serialize,
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};
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use tokio::{
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spawn,
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sync::{
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Mutex,
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mpsc,
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oneshot,
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RwLock,
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watch,
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},
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time::delay_for,
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};
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use tracing::{
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debug, error, info, trace,
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instrument,
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};
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use crate::{
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http_serde,
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prefix_match,
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};
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/*
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Here's what we need to handle:
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When a request comes in:
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- Park the client in response_rendezvous
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- Look up the server ID in request_rendezvous
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- If a server is parked, unpark it and send the request
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- Otherwise, queue the request
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When a server comes to listen:
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- Look up the server ID in request_rendezvous
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- Either return all pending requests, or park the server
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When a server comes to respond:
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- Look up the parked client in response_rendezvous
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- Unpark the client and begin streaming
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So we need these lookups to be fast:
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- Server IDs, where (1 server) or (0 or many clients)
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can be parked
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- Request IDs, where 1 client is parked
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*/
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#[derive (Debug)]
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enum RelayError {
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RelayShuttingDown,
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}
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enum RequestRendezvous {
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ParkedClients (Vec <http_serde::WrappedRequest>),
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ParkedServer (oneshot::Sender <Result <http_serde::WrappedRequest, RelayError>>),
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}
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type ResponseRendezvous = oneshot::Sender <Result <(http_serde::ResponseParts, Body), RelayError>>;
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// Stuff we need to load from the config file and use to
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// set up the HTTP server
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#[derive (Default, Deserialize)]
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pub struct ConfigFile {
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pub port: Option <u16>,
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pub server_tripcodes: HashMap <String, String>,
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}
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// Stuff we actually need at runtime
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struct Config {
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server_tripcodes: HashMap <String, blake3::Hash>,
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}
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impl From <&ConfigFile> for Config {
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fn from (f: &ConfigFile) -> Self {
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let trips = HashMap::from_iter (f.server_tripcodes.iter ()
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.map (|(k, v)| {
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use std::convert::TryInto;
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let bytes: Vec <u8> = base64::decode (v).unwrap ();
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let bytes: [u8; 32] = (&bytes [..]).try_into ().unwrap ();
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let v = blake3::Hash::from (bytes);
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(k.clone (), v)
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}));
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Self {
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server_tripcodes: trips,
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}
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}
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}
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pub struct RelayState {
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config: Config,
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handlebars: Arc <Handlebars <'static>>,
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// Key: Server ID
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request_rendezvous: Mutex <HashMap <String, RequestRendezvous>>,
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// Key: Request ID
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response_rendezvous: RwLock <DashMap <String, ResponseRendezvous>>,
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shutdown_watch_tx: watch::Sender <bool>,
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shutdown_watch_rx: watch::Receiver <bool>,
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}
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impl From <&ConfigFile> for RelayState {
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fn from (config_file: &ConfigFile) -> Self {
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let (shutdown_watch_tx, shutdown_watch_rx) = watch::channel (false);
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Self {
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config: Config::from (config_file),
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handlebars: Arc::new (load_templates ().unwrap ()),
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request_rendezvous: Default::default (),
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response_rendezvous: Default::default (),
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shutdown_watch_tx,
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shutdown_watch_rx,
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}
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}
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}
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impl RelayState {
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pub async fn list_servers (&self) -> Vec <String> {
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self.request_rendezvous.lock ().await.iter ()
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.map (|(k, _)| (*k).clone ())
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.collect ()
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}
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}
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fn ok_reply <B: Into <Body>> (b: B)
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-> Response <Body>
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{
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Response::builder ().status (StatusCode::OK).body (b.into ()).unwrap ()
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}
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fn error_reply (status: StatusCode, b: &str)
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-> Response <Body>
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{
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Response::builder ()
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.status (status)
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.header ("content-type", "text/plain")
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.body (format! ("{}\n", b).into ()).unwrap ()
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}
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// Servers will come here and either handle queued requests from parked clients,
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// or park themselves until a request comes in.
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async fn handle_http_listen (
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state: Arc <RelayState>,
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watcher_code: String,
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api_key: &[u8],
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)
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-> Response <Body>
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{
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let trip_error = error_reply (StatusCode::UNAUTHORIZED, "Bad X-ApiKey");
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let expected_tripcode = match state.config.server_tripcodes.get (&watcher_code) {
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None => {
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error! ("Denied http_listen for non-existent server name {}", watcher_code);
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return trip_error;
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},
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Some (x) => x,
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};
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let actual_tripcode = blake3::hash (api_key);
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if expected_tripcode != &actual_tripcode {
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error! ("Denied http_listen for bad tripcode {}", base64::encode (actual_tripcode.as_bytes ()));
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return trip_error;
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}
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use RequestRendezvous::*;
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let (tx, rx) = oneshot::channel ();
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{
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let mut request_rendezvous = state.request_rendezvous.lock ().await;
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if let Some (ParkedClients (v)) = request_rendezvous.remove (&watcher_code)
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{
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if ! v.is_empty () {
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// 1 or more clients were parked - Make the server
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// handle them immediately
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debug! ("Sending {} parked requests to server {}", v.len (), watcher_code);
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return ok_reply (rmp_serde::to_vec (&v).unwrap ());
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}
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}
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debug! ("Parking server {}", watcher_code);
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request_rendezvous.insert (watcher_code.clone (), ParkedServer (tx));
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}
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// No clients were parked - make the server long-poll
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futures::select! {
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x = rx.fuse () => match x {
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Ok (Ok (one_req)) => {
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debug! ("Unparking server {}", watcher_code);
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ok_reply (rmp_serde::to_vec (&vec! [one_req]).unwrap ())
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},
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Ok (Err (RelayError::RelayShuttingDown)) => error_reply (StatusCode::SERVICE_UNAVAILABLE, "Server is shutting down, try again soon"),
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Err (_) => error_reply (StatusCode::INTERNAL_SERVER_ERROR, "Server error"),
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},
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_ = delay_for (Duration::from_secs (30)).fuse () => {
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debug! ("Timed out http_listen for server {}", watcher_code);
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return error_reply (StatusCode::NO_CONTENT, "No requests now, long-poll again")
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}
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}
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}
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// Servers will come here to stream responses to clients
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async fn handle_http_response (
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req: Request <Body>,
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state: Arc <RelayState>,
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req_id: String,
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)
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-> Response <Body>
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{
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let (parts, mut body) = req.into_parts ();
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let resp_parts: http_serde::ResponseParts = rmp_serde::from_read_ref (&base64::decode (parts.headers.get (crate::PTTH_MAGIC_HEADER).unwrap ()).unwrap ()).unwrap ();
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// Intercept the body packets here so we can check when the stream
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// ends or errors out
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#[derive (Debug)]
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enum BodyFinishedReason {
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StreamFinished,
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ClientDisconnected,
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}
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use BodyFinishedReason::*;
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let (mut body_tx, body_rx) = mpsc::channel (2);
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let (body_finished_tx, body_finished_rx) = oneshot::channel ();
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let mut shutdown_watch_rx = state.shutdown_watch_rx.clone ();
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spawn (async move {
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if shutdown_watch_rx.recv ().await == Some (false) {
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loop {
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let item = body.next ().await;
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if let Some (item) = item {
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if let Ok (bytes) = &item {
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trace! ("Relaying {} bytes", bytes.len ());
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}
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futures::select! {
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x = body_tx.send (item).fuse () => if let Err (_) = x {
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info! ("Body closed while relaying. (Client hung up?)");
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body_finished_tx.send (ClientDisconnected).unwrap ();
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break;
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},
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_ = shutdown_watch_rx.recv ().fuse () => {
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debug! ("Closing stream: relay is shutting down");
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break;
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},
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}
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}
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else {
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debug! ("Finished relaying bytes");
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body_finished_tx.send (StreamFinished).unwrap ();
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break;
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}
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}
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}
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else {
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debug! ("Can't relay bytes, relay is shutting down");
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}
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});
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let body = Body::wrap_stream (body_rx);
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let tx = {
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let response_rendezvous = state.response_rendezvous.read ().await;
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match response_rendezvous.remove (&req_id) {
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None => {
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error! ("Server tried to respond to non-existent request");
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return error_reply (StatusCode::BAD_REQUEST, "Request ID not found in response_rendezvous");
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},
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Some ((_, x)) => x,
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}
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};
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// UKAUFFY4 (Send half)
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if tx.send (Ok ((resp_parts, body))).is_err () {
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let msg = "Failed to connect to client";
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error! (msg);
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return error_reply (StatusCode::BAD_GATEWAY, msg);
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}
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debug! ("Connected server to client for streaming.");
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match body_finished_rx.await {
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Ok (StreamFinished) => {
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error_reply (StatusCode::OK, "StreamFinished")
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},
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Ok (ClientDisconnected) => {
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error_reply (StatusCode::OK, "ClientDisconnected")
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},
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Err (e) => {
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debug! ("body_finished_rx {}", e);
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error_reply (StatusCode::OK, "body_finished_rx Err")
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},
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}
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}
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// Clients will come here to start requests, and always park for at least
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// a short amount of time.
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async fn handle_http_request (
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req: http::request::Parts,
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uri: String,
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state: Arc <RelayState>,
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watcher_code: String
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)
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-> Response <Body>
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{
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if ! state.config.server_tripcodes.contains_key (&watcher_code) {
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return error_reply (StatusCode::NOT_FOUND, "Unknown server");
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}
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let req = match http_serde::RequestParts::from_hyper (req.method, uri, req.headers) {
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Ok (x) => x,
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_ => return error_reply (StatusCode::BAD_REQUEST, "Bad request"),
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};
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let (tx, rx) = oneshot::channel ();
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let req_id = ulid::Ulid::new ().to_string ();
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{
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let response_rendezvous = state.response_rendezvous.read ().await;
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response_rendezvous.insert (req_id.clone (), tx);
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}
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trace! ("Created request {}", req_id);
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{
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let mut request_rendezvous = state.request_rendezvous.lock ().await;
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let wrapped = http_serde::WrappedRequest {
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id: req_id.clone (),
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req,
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};
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use RequestRendezvous::*;
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let new_rendezvous = match request_rendezvous.remove (&watcher_code) {
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Some (ParkedClients (mut v)) => {
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debug! ("Parking request {} ({} already queued)", req_id, v.len ());
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v.push (wrapped);
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ParkedClients (v)
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},
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Some (ParkedServer (s)) => {
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// If sending to the server fails, queue it
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match s.send (Ok (wrapped)) {
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Ok (()) => {
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// TODO: This can actually still fail, if the server
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// disconnects right as we're sending this.
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// Then what?
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debug! (
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"Sending request {} directly to server {}",
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req_id,
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watcher_code,
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);
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ParkedClients (vec! [])
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},
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Err (Ok (wrapped)) => {
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debug! ("Parking request {}", req_id);
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ParkedClients (vec! [wrapped])
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},
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Err (_) => unreachable! (),
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}
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},
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None => {
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debug! ("Parking request {}", req_id);
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ParkedClients (vec! [wrapped])
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},
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};
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request_rendezvous.insert (watcher_code, new_rendezvous);
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}
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let timeout = tokio::time::delay_for (std::time::Duration::from_secs (30));
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let received = tokio::select! {
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val = rx => val,
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() = timeout => {
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debug! ("Timed out request {}", req_id);
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return error_reply (StatusCode::GATEWAY_TIMEOUT, "Remote server never responded")
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},
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};
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// UKAUFFY4 (Receive half)
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match received {
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Ok (Ok ((parts, body))) => {
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let mut resp = Response::builder ()
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.status (hyper::StatusCode::from (parts.status_code));
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for (k, v) in parts.headers.into_iter () {
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resp = resp.header (&k, v);
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}
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debug! ("Unparked request {}", req_id);
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resp.body (body)
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.unwrap ()
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},
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Ok (Err (RelayError::RelayShuttingDown)) => {
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error_reply (StatusCode::GATEWAY_TIMEOUT, "Relay shutting down")
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},
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Err (_) => {
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debug! ("Responder sender dropped for request {}", req_id);
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error_reply (StatusCode::GATEWAY_TIMEOUT, "Remote server timed out")
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},
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}
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}
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|
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#[instrument (level = "trace", skip (req, state))]
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async fn handle_all (req: Request <Body>, state: Arc <RelayState>)
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-> Result <Response <Body>, Infallible>
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{
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let path = req.uri ().path ();
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//println! ("{}", path);
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debug! ("Request path: {}", path);
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let api_key = req.headers ().get ("X-ApiKey");
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if req.method () == Method::POST {
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// This is stuff the server can use. Clients can't
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// POST right now
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return Ok (if let Some (request_code) = prefix_match ("/7ZSFUKGV/http_response/", path) {
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let request_code = request_code.into ();
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handle_http_response (req, state, request_code).await
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}
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else {
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error_reply (StatusCode::BAD_REQUEST, "Can't POST this")
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});
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}
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Ok (if let Some (listen_code) = prefix_match ("/7ZSFUKGV/http_listen/", path) {
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let api_key = match api_key {
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None => return Ok (error_reply (StatusCode::UNAUTHORIZED, "Can't register as server without an API key")),
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Some (x) => x,
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};
|
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handle_http_listen (state, listen_code.into (), api_key.as_bytes ()).await
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}
|
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else if let Some (rest) = prefix_match ("/frontend/servers/", path) {
|
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if rest == "" {
|
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#[derive (Serialize)]
|
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struct ServerEntry <'a> {
|
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path: &'a str,
|
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name: &'a str,
|
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}
|
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|
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#[derive (Serialize)]
|
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struct ServerListPage <'a> {
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servers: Vec <ServerEntry <'a>>,
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}
|
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|
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let names = state.list_servers ().await;
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|
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//println! ("Found {} servers", names.len ());
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let page = ServerListPage {
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servers: names.iter ()
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.map (|name| ServerEntry {
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name: &name,
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path: &name,
|
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})
|
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.collect (),
|
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};
|
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|
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let s = state.handlebars.render ("relay_server_list", &page).unwrap ();
|
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ok_reply (s)
|
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}
|
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else if let Some (idx) = rest.find ('/') {
|
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let listen_code = String::from (&rest [0..idx]);
|
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let path = String::from (&rest [idx..]);
|
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let (parts, _) = req.into_parts ();
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|
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handle_http_request (parts, path, state, listen_code).await
|
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}
|
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else {
|
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error_reply (StatusCode::BAD_REQUEST, "Bad URI format")
|
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}
|
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}
|
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else if path == "/" {
|
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let s = state.handlebars.render ("relay_root", &()).unwrap ();
|
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ok_reply (s)
|
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}
|
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else if path == "/frontend/relay_up_check" {
|
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error_reply (StatusCode::OK, "Relay is up")
|
|
}
|
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else {
|
|
error_reply (StatusCode::OK, "Hi")
|
|
})
|
|
}
|
|
|
|
pub fn load_templates ()
|
|
-> Result <Handlebars <'static>, Box <dyn Error>>
|
|
{
|
|
let mut handlebars = Handlebars::new ();
|
|
handlebars.set_strict_mode (true);
|
|
|
|
for (k, v) in vec! [
|
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("relay_server_list", "relay_server_list.html"),
|
|
("relay_root", "relay_root.html"),
|
|
].into_iter () {
|
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handlebars.register_template_file (k, format! ("ptth_handlebars/{}", v))?;
|
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}
|
|
|
|
Ok (handlebars)
|
|
}
|
|
|
|
pub async fn run_relay (
|
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state: Arc <RelayState>,
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shutdown_oneshot: oneshot::Receiver <()>
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)
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-> Result <(), Box <dyn Error>>
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{
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let addr = SocketAddr::from ((
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[0, 0, 0, 0],
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4000,
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));
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|
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{
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let mut tripcode_set = HashSet::new ();
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|
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for (_, v) in state.config.server_tripcodes.iter () {
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if ! tripcode_set.insert (v) {
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panic! ("Two servers have the same tripcode. That is not allowed.");
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}
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}
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}
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|
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info! ("Loaded {} server tripcodes", state.config.server_tripcodes.len ());
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|
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let make_svc = make_service_fn (|_conn| {
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let state = state.clone ();
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|
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async {
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Ok::<_, Infallible> (service_fn (move |req| {
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let state = state.clone ();
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|
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|
handle_all (req, state)
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|
}))
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|
}
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|
});
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|
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let server = Server::bind (&addr)
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.serve (make_svc);
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|
|
|
|
|
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server.with_graceful_shutdown (async {
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|
shutdown_oneshot.await.ok ();
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|
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|
state.shutdown_watch_tx.broadcast (true).unwrap ();
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|
|
|
use RelayError::*;
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|
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|
let mut response_rendezvous = state.response_rendezvous.write ().await;
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|
let mut swapped = DashMap::default ();
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|
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|
std::mem::swap (&mut swapped, &mut response_rendezvous);
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|
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|
for (_, sender) in swapped.into_iter () {
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|
sender.send (Err (RelayShuttingDown)).ok ();
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|
}
|
|
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|
let mut request_rendezvous = state.request_rendezvous.lock ().await;
|
|
|
|
for (_, x) in request_rendezvous.drain () {
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|
use RequestRendezvous::*;
|
|
|
|
match x {
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|
ParkedClients (_) => (),
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|
ParkedServer (sender) => drop (sender.send (Err (RelayShuttingDown))),
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|
}
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|
}
|
|
|
|
debug! ("Performed all cleanup");
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|
}).await?;
|
|
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|
Ok (())
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|
}
|
|
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|
#[cfg (test)]
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|
mod tests {
|
|
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|
}
|