Line data Source code
1 : //! Server-side asynchronous Postgres connection, as limited as we need.
2 : //! To use, create PostgresBackend and run() it, passing the Handler
3 : //! implementation determining how to process the queries. Currently its API
4 : //! is rather narrow, but we can extend it once required.
5 : #![deny(unsafe_code)]
6 : #![deny(clippy::undocumented_unsafe_blocks)]
7 : use anyhow::Context;
8 : use bytes::Bytes;
9 : use futures::pin_mut;
10 : use serde::{Deserialize, Serialize};
11 : use std::io::ErrorKind;
12 : use std::net::SocketAddr;
13 : use std::pin::Pin;
14 : use std::sync::Arc;
15 : use std::task::{ready, Poll};
16 : use std::{fmt, io};
17 : use std::{future::Future, str::FromStr};
18 : use tokio::io::{AsyncRead, AsyncWrite};
19 : use tokio_rustls::TlsAcceptor;
20 : use tracing::{debug, error, info, trace, warn};
21 :
22 : use pq_proto::framed::{ConnectionError, Framed, FramedReader, FramedWriter};
23 : use pq_proto::{
24 : BeMessage, FeMessage, FeStartupPacket, ProtocolError, SQLSTATE_ADMIN_SHUTDOWN,
25 : SQLSTATE_INTERNAL_ERROR, SQLSTATE_SUCCESSFUL_COMPLETION,
26 : };
27 :
28 : /// An error, occurred during query processing:
29 : /// either during the connection ([`ConnectionError`]) or before/after it.
30 116 : #[derive(thiserror::Error, Debug)]
31 : pub enum QueryError {
32 : /// The connection was lost while processing the query.
33 : #[error(transparent)]
34 : Disconnected(#[from] ConnectionError),
35 : /// We were instructed to shutdown while processing the query
36 : #[error("Shutting down")]
37 : Shutdown,
38 : /// Query handler indicated that client should reconnect
39 : #[error("Server requested reconnect")]
40 : Reconnect,
41 : /// Query named an entity that was not found
42 : #[error("Not found: {0}")]
43 : NotFound(std::borrow::Cow<'static, str>),
44 : /// Authentication failure
45 : #[error("Unauthorized: {0}")]
46 : Unauthorized(std::borrow::Cow<'static, str>),
47 : #[error("Simulated Connection Error")]
48 : SimulatedConnectionError,
49 : /// Some other error
50 : #[error(transparent)]
51 : Other(#[from] anyhow::Error),
52 : }
53 :
54 : impl From<io::Error> for QueryError {
55 450 : fn from(e: io::Error) -> Self {
56 450 : Self::Disconnected(ConnectionError::Io(e))
57 450 : }
58 : }
59 :
60 : impl QueryError {
61 183 : pub fn pg_error_code(&self) -> &'static [u8; 5] {
62 183 : match self {
63 116 : Self::Disconnected(_) | Self::SimulatedConnectionError | Self::Reconnect => b"08006", // connection failure
64 0 : Self::Shutdown => SQLSTATE_ADMIN_SHUTDOWN,
65 23 : Self::Unauthorized(_) | Self::NotFound(_) => SQLSTATE_INTERNAL_ERROR,
66 44 : Self::Other(_) => SQLSTATE_INTERNAL_ERROR, // internal error
67 : }
68 183 : }
69 : }
70 :
71 : /// Returns true if the given error is a normal consequence of a network issue,
72 : /// or the client closing the connection. These errors can happen during normal
73 : /// operations, and don't indicate a bug in our code.
74 1302 : pub fn is_expected_io_error(e: &io::Error) -> bool {
75 : use io::ErrorKind::*;
76 0 : matches!(
77 1302 : e.kind(),
78 : BrokenPipe | ConnectionRefused | ConnectionAborted | ConnectionReset | TimedOut
79 : )
80 1302 : }
81 :
82 : #[async_trait::async_trait]
83 : pub trait Handler<IO> {
84 : /// Handle single query.
85 : /// postgres_backend will issue ReadyForQuery after calling this (this
86 : /// might be not what we want after CopyData streaming, but currently we don't
87 : /// care). It will also flush out the output buffer.
88 : async fn process_query(
89 : &mut self,
90 : pgb: &mut PostgresBackend<IO>,
91 : query_string: &str,
92 : ) -> Result<(), QueryError>;
93 :
94 : /// Called on startup packet receival, allows to process params.
95 : ///
96 : /// If Ok(false) is returned postgres_backend will skip auth -- that is needed for new users
97 : /// creation is the proxy code. That is quite hacky and ad-hoc solution, may be we could allow
98 : /// to override whole init logic in implementations.
99 7 : fn startup(
100 7 : &mut self,
101 7 : _pgb: &mut PostgresBackend<IO>,
102 7 : _sm: &FeStartupPacket,
103 7 : ) -> Result<(), QueryError> {
104 7 : Ok(())
105 7 : }
106 :
107 : /// Check auth jwt
108 0 : fn check_auth_jwt(
109 0 : &mut self,
110 0 : _pgb: &mut PostgresBackend<IO>,
111 0 : _jwt_response: &[u8],
112 0 : ) -> Result<(), QueryError> {
113 0 : Err(QueryError::Other(anyhow::anyhow!("JWT auth failed")))
114 0 : }
115 : }
116 :
117 : /// PostgresBackend protocol state.
118 : /// XXX: The order of the constructors matters.
119 66024 : #[derive(Clone, Copy, PartialEq, Eq, PartialOrd)]
120 : pub enum ProtoState {
121 : /// Nothing happened yet.
122 : Initialization,
123 : /// Encryption handshake is done; waiting for encrypted Startup message.
124 : Encrypted,
125 : /// Waiting for password (auth token).
126 : Authentication,
127 : /// Performed handshake and auth, ReadyForQuery is issued.
128 : Established,
129 : Closed,
130 : }
131 :
132 0 : #[derive(Clone, Copy)]
133 : pub enum ProcessMsgResult {
134 : Continue,
135 : Break,
136 : }
137 :
138 : /// Either plain TCP stream or encrypted one, implementing AsyncRead + AsyncWrite.
139 : pub enum MaybeTlsStream<IO> {
140 : Unencrypted(IO),
141 : Tls(Box<tokio_rustls::server::TlsStream<IO>>),
142 : }
143 :
144 : impl<IO: AsyncRead + AsyncWrite + Unpin> AsyncWrite for MaybeTlsStream<IO> {
145 9165064 : fn poll_write(
146 9165064 : self: Pin<&mut Self>,
147 9165064 : cx: &mut std::task::Context<'_>,
148 9165064 : buf: &[u8],
149 9165064 : ) -> Poll<io::Result<usize>> {
150 9165064 : match self.get_mut() {
151 9165060 : Self::Unencrypted(stream) => Pin::new(stream).poll_write(cx, buf),
152 4 : Self::Tls(stream) => Pin::new(stream).poll_write(cx, buf),
153 : }
154 9165064 : }
155 9175788 : fn poll_flush(self: Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> Poll<io::Result<()>> {
156 9175788 : match self.get_mut() {
157 9175784 : Self::Unencrypted(stream) => Pin::new(stream).poll_flush(cx),
158 4 : Self::Tls(stream) => Pin::new(stream).poll_flush(cx),
159 : }
160 9175788 : }
161 13204 : fn poll_shutdown(
162 13204 : self: Pin<&mut Self>,
163 13204 : cx: &mut std::task::Context<'_>,
164 13204 : ) -> Poll<io::Result<()>> {
165 13204 : match self.get_mut() {
166 13204 : Self::Unencrypted(stream) => Pin::new(stream).poll_shutdown(cx),
167 0 : Self::Tls(stream) => Pin::new(stream).poll_shutdown(cx),
168 : }
169 13204 : }
170 : }
171 : impl<IO: AsyncRead + AsyncWrite + Unpin> AsyncRead for MaybeTlsStream<IO> {
172 20137743 : fn poll_read(
173 20137743 : self: Pin<&mut Self>,
174 20137743 : cx: &mut std::task::Context<'_>,
175 20137743 : buf: &mut tokio::io::ReadBuf<'_>,
176 20137743 : ) -> Poll<io::Result<()>> {
177 20137743 : match self.get_mut() {
178 20137733 : Self::Unencrypted(stream) => Pin::new(stream).poll_read(cx, buf),
179 10 : Self::Tls(stream) => Pin::new(stream).poll_read(cx, buf),
180 : }
181 20137743 : }
182 : }
183 :
184 50578 : #[derive(Debug, PartialEq, Eq, Clone, Copy, Serialize, Deserialize)]
185 : pub enum AuthType {
186 : Trust,
187 : // This mimics postgres's AuthenticationCleartextPassword but instead of password expects JWT
188 : NeonJWT,
189 : }
190 :
191 : impl FromStr for AuthType {
192 : type Err = anyhow::Error;
193 :
194 1984 : fn from_str(s: &str) -> Result<Self, Self::Err> {
195 1984 : match s {
196 1984 : "Trust" => Ok(Self::Trust),
197 44 : "NeonJWT" => Ok(Self::NeonJWT),
198 0 : _ => anyhow::bail!("invalid value \"{s}\" for auth type"),
199 : }
200 1984 : }
201 : }
202 :
203 : impl fmt::Display for AuthType {
204 1986 : fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
205 1986 : f.write_str(match self {
206 1942 : AuthType::Trust => "Trust",
207 44 : AuthType::NeonJWT => "NeonJWT",
208 : })
209 1986 : }
210 : }
211 :
212 : /// Either full duplex Framed or write only half; the latter is left in
213 : /// PostgresBackend after call to `split`. In principle we could always store a
214 : /// pair of splitted handles, but that would force to to pay splitting price
215 : /// (Arc and kinda mutex inside polling) for all uses (e.g. pageserver).
216 : enum MaybeWriteOnly<IO> {
217 : Full(Framed<MaybeTlsStream<IO>>),
218 : WriteOnly(FramedWriter<MaybeTlsStream<IO>>),
219 : Broken, // temporary value palmed off during the split
220 : }
221 :
222 : impl<IO: AsyncRead + AsyncWrite + Unpin> MaybeWriteOnly<IO> {
223 26003 : async fn read_startup_message(&mut self) -> Result<Option<FeStartupPacket>, ConnectionError> {
224 26003 : match self {
225 26003 : MaybeWriteOnly::Full(framed) => framed.read_startup_message().await,
226 : MaybeWriteOnly::WriteOnly(_) => {
227 0 : Err(io::Error::new(ErrorKind::Other, "reading from write only half").into())
228 : }
229 0 : MaybeWriteOnly::Broken => panic!("IO on invalid MaybeWriteOnly"),
230 : }
231 26003 : }
232 :
233 5757732 : async fn read_message(&mut self) -> Result<Option<FeMessage>, ConnectionError> {
234 5757732 : match self {
235 5757732 : MaybeWriteOnly::Full(framed) => framed.read_message().await,
236 : MaybeWriteOnly::WriteOnly(_) => {
237 0 : Err(io::Error::new(ErrorKind::Other, "reading from write only half").into())
238 : }
239 0 : MaybeWriteOnly::Broken => panic!("IO on invalid MaybeWriteOnly"),
240 : }
241 5757538 : }
242 :
243 9181355 : fn write_message_noflush(&mut self, msg: &BeMessage<'_>) -> Result<(), ProtocolError> {
244 9181355 : match self {
245 6712864 : MaybeWriteOnly::Full(framed) => framed.write_message(msg),
246 2468491 : MaybeWriteOnly::WriteOnly(framed_writer) => framed_writer.write_message_noflush(msg),
247 0 : MaybeWriteOnly::Broken => panic!("IO on invalid MaybeWriteOnly"),
248 : }
249 9181355 : }
250 :
251 9171578 : async fn flush(&mut self) -> io::Result<()> {
252 9171578 : match self {
253 6703087 : MaybeWriteOnly::Full(framed) => framed.flush().await,
254 2468491 : MaybeWriteOnly::WriteOnly(framed_writer) => framed_writer.flush().await,
255 0 : MaybeWriteOnly::Broken => panic!("IO on invalid MaybeWriteOnly"),
256 : }
257 9163044 : }
258 :
259 : /// Cancellation safe as long as the underlying IO is cancellation safe.
260 13569 : async fn shutdown(&mut self) -> io::Result<()> {
261 13569 : match self {
262 13569 : MaybeWriteOnly::Full(framed) => framed.shutdown().await,
263 0 : MaybeWriteOnly::WriteOnly(framed_writer) => framed_writer.shutdown().await,
264 0 : MaybeWriteOnly::Broken => panic!("IO on invalid MaybeWriteOnly"),
265 : }
266 13569 : }
267 : }
268 :
269 : pub struct PostgresBackend<IO> {
270 : framed: MaybeWriteOnly<IO>,
271 :
272 : pub state: ProtoState,
273 :
274 : auth_type: AuthType,
275 :
276 : peer_addr: SocketAddr,
277 : pub tls_config: Option<Arc<rustls::ServerConfig>>,
278 : }
279 :
280 : pub type PostgresBackendTCP = PostgresBackend<tokio::net::TcpStream>;
281 :
282 0 : pub fn query_from_cstring(query_string: Bytes) -> Vec<u8> {
283 0 : let mut query_string = query_string.to_vec();
284 0 : if let Some(ch) = query_string.last() {
285 0 : if *ch == 0 {
286 0 : query_string.pop();
287 0 : }
288 0 : }
289 0 : query_string
290 0 : }
291 :
292 : /// Cast a byte slice to a string slice, dropping null terminator if there's one.
293 14786 : fn cstr_to_str(bytes: &[u8]) -> anyhow::Result<&str> {
294 14786 : let without_null = bytes.strip_suffix(&[0]).unwrap_or(bytes);
295 14786 : std::str::from_utf8(without_null).map_err(|e| e.into())
296 14786 : }
297 :
298 : impl PostgresBackend<tokio::net::TcpStream> {
299 7 : pub fn new(
300 7 : socket: tokio::net::TcpStream,
301 7 : auth_type: AuthType,
302 7 : tls_config: Option<Arc<rustls::ServerConfig>>,
303 7 : ) -> io::Result<Self> {
304 7 : let peer_addr = socket.peer_addr()?;
305 7 : let stream = MaybeTlsStream::Unencrypted(socket);
306 7 :
307 7 : Ok(Self {
308 7 : framed: MaybeWriteOnly::Full(Framed::new(stream)),
309 7 : state: ProtoState::Initialization,
310 7 : auth_type,
311 7 : tls_config,
312 7 : peer_addr,
313 7 : })
314 7 : }
315 : }
316 :
317 : impl<IO: AsyncRead + AsyncWrite + Unpin> PostgresBackend<IO> {
318 14011 : pub fn new_from_io(
319 14011 : socket: IO,
320 14011 : peer_addr: SocketAddr,
321 14011 : auth_type: AuthType,
322 14011 : tls_config: Option<Arc<rustls::ServerConfig>>,
323 14011 : ) -> io::Result<Self> {
324 14011 : let stream = MaybeTlsStream::Unencrypted(socket);
325 14011 :
326 14011 : Ok(Self {
327 14011 : framed: MaybeWriteOnly::Full(Framed::new(stream)),
328 14011 : state: ProtoState::Initialization,
329 14011 : auth_type,
330 14011 : tls_config,
331 14011 : peer_addr,
332 14011 : })
333 14011 : }
334 :
335 2613 : pub fn get_peer_addr(&self) -> &SocketAddr {
336 2613 : &self.peer_addr
337 2613 : }
338 :
339 : /// Read full message or return None if connection is cleanly closed with no
340 : /// unprocessed data.
341 5757543 : pub async fn read_message(&mut self) -> Result<Option<FeMessage>, ConnectionError> {
342 5757543 : if let ProtoState::Closed = self.state {
343 27 : Ok(None)
344 : } else {
345 5757516 : match self.framed.read_message().await {
346 5757255 : Ok(m) => {
347 0 : trace!("read msg {:?}", m);
348 5757255 : Ok(m)
349 : }
350 67 : Err(e) => {
351 67 : // remember not to try to read anymore
352 67 : self.state = ProtoState::Closed;
353 67 : Err(e)
354 : }
355 : }
356 : }
357 5757349 : }
358 :
359 : /// Write message into internal output buffer, doesn't flush it. Technically
360 : /// error type can be only ProtocolError here (if, unlikely, serialization
361 : /// fails), but callers typically wrap it anyway.
362 9181355 : pub fn write_message_noflush(
363 9181355 : &mut self,
364 9181355 : message: &BeMessage<'_>,
365 9181355 : ) -> Result<&mut Self, ConnectionError> {
366 9181355 : self.framed.write_message_noflush(message)?;
367 9181355 : trace!("wrote msg {:?}", message);
368 9181355 : Ok(self)
369 9181355 : }
370 :
371 : /// Flush output buffer into the socket.
372 9171578 : pub async fn flush(&mut self) -> io::Result<()> {
373 9171578 : self.framed.flush().await
374 9163044 : }
375 :
376 : /// Polling version of `flush()`, saves the caller need to pin.
377 1024407 : pub fn poll_flush(
378 1024407 : &mut self,
379 1024407 : cx: &mut std::task::Context<'_>,
380 1024407 : ) -> Poll<Result<(), std::io::Error>> {
381 1024407 : let flush_fut = self.flush();
382 1024407 : pin_mut!(flush_fut);
383 1024407 : flush_fut.poll(cx)
384 1024407 : }
385 :
386 : /// Write message into internal output buffer and flush it to the stream.
387 2497404 : pub async fn write_message(
388 2497404 : &mut self,
389 2497404 : message: &BeMessage<'_>,
390 2497404 : ) -> Result<&mut Self, ConnectionError> {
391 2497404 : self.write_message_noflush(message)?;
392 2497404 : self.flush().await?;
393 2497382 : Ok(self)
394 2497392 : }
395 :
396 : /// Returns an AsyncWrite implementation that wraps all the data written
397 : /// to it in CopyData messages, and writes them to the connection
398 : ///
399 : /// The caller is responsible for sending CopyOutResponse and CopyDone messages.
400 609 : pub fn copyout_writer(&mut self) -> CopyDataWriter<IO> {
401 609 : CopyDataWriter { pgb: self }
402 609 : }
403 :
404 : /// Wrapper for run_message_loop() that shuts down socket when we are done
405 14018 : pub async fn run<F, S>(
406 14018 : mut self,
407 14018 : handler: &mut impl Handler<IO>,
408 14018 : shutdown_watcher: F,
409 14018 : ) -> Result<(), QueryError>
410 14018 : where
411 14018 : F: Fn() -> S + Clone,
412 14018 : S: Future,
413 14018 : {
414 14018 : let ret = self
415 14018 : .run_message_loop(handler, shutdown_watcher.clone())
416 14064302 : .await;
417 :
418 13569 : tokio::select! {
419 13569 : _ = shutdown_watcher() => {
420 13569 : // do nothing; we most likely got already stopped by shutdown and will log it next.
421 13569 : }
422 13569 : _ = self.framed.shutdown() => {
423 13569 : // socket might be already closed, e.g. if previously received error,
424 13569 : // so ignore result.
425 13569 : },
426 13569 : }
427 :
428 466 : match ret {
429 13103 : Ok(()) => Ok(()),
430 : Err(QueryError::Shutdown) => {
431 0 : info!("Stopped due to shutdown");
432 0 : Ok(())
433 : }
434 : Err(QueryError::Reconnect) => {
435 : // Dropping out of this loop implicitly disconnects
436 0 : info!("Stopped due to handler reconnect request");
437 0 : Ok(())
438 : }
439 406 : Err(QueryError::Disconnected(e)) => {
440 406 : info!("Disconnected ({e:#})");
441 : // Disconnection is not an error: we just use it that way internally to drop
442 : // out of loops.
443 406 : Ok(())
444 : }
445 60 : e => e,
446 : }
447 13569 : }
448 :
449 14018 : async fn run_message_loop<F, S>(
450 14018 : &mut self,
451 14018 : handler: &mut impl Handler<IO>,
452 14018 : shutdown_watcher: F,
453 14018 : ) -> Result<(), QueryError>
454 14018 : where
455 14018 : F: Fn() -> S,
456 14018 : S: Future,
457 14018 : {
458 0 : trace!("postgres backend to {:?} started", self.peer_addr);
459 :
460 14018 : tokio::select!(
461 : biased;
462 :
463 : _ = shutdown_watcher() => {
464 : // We were requested to shut down.
465 0 : tracing::info!("shutdown request received during handshake");
466 : return Err(QueryError::Shutdown)
467 : },
468 :
469 14018 : handshake_r = self.handshake(handler) => {
470 : handshake_r?;
471 : }
472 : );
473 :
474 : // Authentication completed
475 14012 : let mut query_string = Bytes::new();
476 32236 : while let Some(msg) = tokio::select!(
477 : biased;
478 : _ = shutdown_watcher() => {
479 : // We were requested to shut down.
480 0 : tracing::info!("shutdown request received in run_message_loop");
481 : return Err(QueryError::Shutdown)
482 : },
483 32232 : msg = self.read_message() => { msg },
484 36 : )? {
485 0 : trace!("got message {:?}", msg);
486 :
487 14022412 : let result = self.process_message(handler, msg, &mut query_string).await;
488 20174 : tokio::select!(
489 : biased;
490 : _ = shutdown_watcher() => {
491 : // We were requested to shut down.
492 0 : tracing::info!("shutdown request received during response flush");
493 :
494 : // If we exited process_message with a shutdown error, there may be
495 : // some valid response content on in our transmit buffer: permit sending
496 : // this within a short timeout. This is a best effort thing so we don't
497 : // care about the result.
498 : tokio::time::timeout(std::time::Duration::from_millis(500), self.flush()).await.ok();
499 :
500 : return Err(QueryError::Shutdown)
501 : },
502 20174 : flush_r = self.flush() => {
503 : flush_r?;
504 : }
505 : );
506 :
507 19809 : match result? {
508 : ProcessMsgResult::Continue => {
509 18224 : continue;
510 : }
511 1526 : ProcessMsgResult::Break => break,
512 : }
513 : }
514 :
515 0 : trace!("postgres backend to {:?} exited", self.peer_addr);
516 13103 : Ok(())
517 13569 : }
518 :
519 : /// Try to upgrade MaybeTlsStream into actual TLS one, performing handshake.
520 2 : async fn tls_upgrade(
521 2 : src: MaybeTlsStream<IO>,
522 2 : tls_config: Arc<rustls::ServerConfig>,
523 2 : ) -> anyhow::Result<MaybeTlsStream<IO>> {
524 2 : match src {
525 2 : MaybeTlsStream::Unencrypted(s) => {
526 2 : let acceptor = TlsAcceptor::from(tls_config);
527 4 : let tls_stream = acceptor.accept(s).await?;
528 2 : Ok(MaybeTlsStream::Tls(Box::new(tls_stream)))
529 : }
530 : MaybeTlsStream::Tls(_) => {
531 0 : anyhow::bail!("TLS already started");
532 : }
533 : }
534 2 : }
535 :
536 2 : async fn start_tls(&mut self) -> anyhow::Result<()> {
537 2 : // temporary replace stream with fake to cook TLS one, Indiana Jones style
538 2 : match std::mem::replace(&mut self.framed, MaybeWriteOnly::Broken) {
539 2 : MaybeWriteOnly::Full(framed) => {
540 2 : let tls_config = self
541 2 : .tls_config
542 2 : .as_ref()
543 2 : .context("start_tls called without conf")?
544 2 : .clone();
545 2 : let tls_framed = framed
546 2 : .map_stream(|s| PostgresBackend::tls_upgrade(s, tls_config))
547 4 : .await?;
548 : // push back ready TLS stream
549 2 : self.framed = MaybeWriteOnly::Full(tls_framed);
550 2 : Ok(())
551 : }
552 : MaybeWriteOnly::WriteOnly(_) => {
553 0 : anyhow::bail!("TLS upgrade attempt in split state")
554 : }
555 0 : MaybeWriteOnly::Broken => panic!("TLS upgrade on framed in invalid state"),
556 : }
557 2 : }
558 :
559 : /// Split off owned read part from which messages can be read in different
560 : /// task/thread.
561 2613 : pub fn split(&mut self) -> anyhow::Result<PostgresBackendReader<IO>> {
562 2613 : // temporary replace stream with fake to cook split one, Indiana Jones style
563 2613 : match std::mem::replace(&mut self.framed, MaybeWriteOnly::Broken) {
564 2613 : MaybeWriteOnly::Full(framed) => {
565 2613 : let (reader, writer) = framed.split();
566 2613 : self.framed = MaybeWriteOnly::WriteOnly(writer);
567 2613 : Ok(PostgresBackendReader {
568 2613 : reader,
569 2613 : closed: false,
570 2613 : })
571 : }
572 : MaybeWriteOnly::WriteOnly(_) => {
573 0 : anyhow::bail!("PostgresBackend is already split")
574 : }
575 0 : MaybeWriteOnly::Broken => panic!("split on framed in invalid state"),
576 : }
577 2613 : }
578 :
579 : /// Join read part back.
580 2183 : pub fn unsplit(&mut self, reader: PostgresBackendReader<IO>) -> anyhow::Result<()> {
581 2183 : // temporary replace stream with fake to cook joined one, Indiana Jones style
582 2183 : match std::mem::replace(&mut self.framed, MaybeWriteOnly::Broken) {
583 : MaybeWriteOnly::Full(_) => {
584 0 : anyhow::bail!("PostgresBackend is not split")
585 : }
586 2183 : MaybeWriteOnly::WriteOnly(writer) => {
587 2183 : let joined = Framed::unsplit(reader.reader, writer);
588 2183 : self.framed = MaybeWriteOnly::Full(joined);
589 2183 : // if reader encountered connection error, do not attempt reading anymore
590 2183 : if reader.closed {
591 214 : self.state = ProtoState::Closed;
592 1969 : }
593 2183 : Ok(())
594 : }
595 0 : MaybeWriteOnly::Broken => panic!("unsplit on framed in invalid state"),
596 : }
597 2183 : }
598 :
599 : /// Perform handshake with the client, transitioning to Established.
600 : /// In case of EOF during handshake logs this, sets state to Closed and returns Ok(()).
601 14018 : async fn handshake(&mut self, handler: &mut impl Handler<IO>) -> Result<(), QueryError> {
602 40021 : while self.state < ProtoState::Authentication {
603 26003 : match self.framed.read_startup_message().await? {
604 26003 : Some(msg) => {
605 26003 : self.process_startup_message(handler, msg).await?;
606 : }
607 : None => {
608 0 : trace!(
609 0 : "postgres backend to {:?} received EOF during handshake",
610 0 : self.peer_addr
611 0 : );
612 0 : self.state = ProtoState::Closed;
613 0 : return Err(QueryError::Disconnected(ConnectionError::Protocol(
614 0 : ProtocolError::Protocol("EOF during handshake".to_string()),
615 0 : )));
616 : }
617 : }
618 : }
619 :
620 : // Perform auth, if needed.
621 14018 : if self.state == ProtoState::Authentication {
622 216 : match self.framed.read_message().await? {
623 211 : Some(FeMessage::PasswordMessage(m)) => {
624 211 : assert!(self.auth_type == AuthType::NeonJWT);
625 :
626 211 : let (_, jwt_response) = m.split_last().context("protocol violation")?;
627 :
628 211 : if let Err(e) = handler.check_auth_jwt(self, jwt_response) {
629 1 : self.write_message_noflush(&BeMessage::ErrorResponse(
630 1 : &short_error(&e),
631 1 : Some(e.pg_error_code()),
632 1 : ))?;
633 1 : return Err(e);
634 210 : }
635 210 :
636 210 : self.write_message_noflush(&BeMessage::AuthenticationOk)?
637 210 : .write_message_noflush(&BeMessage::CLIENT_ENCODING)?
638 210 : .write_message(&BeMessage::ReadyForQuery)
639 0 : .await?;
640 210 : self.state = ProtoState::Established;
641 : }
642 0 : Some(m) => {
643 0 : return Err(QueryError::Other(anyhow::anyhow!(
644 0 : "Unexpected message {:?} while waiting for handshake",
645 0 : m
646 0 : )));
647 : }
648 : None => {
649 0 : trace!(
650 0 : "postgres backend to {:?} received EOF during auth",
651 0 : self.peer_addr
652 0 : );
653 5 : self.state = ProtoState::Closed;
654 5 : return Err(QueryError::Disconnected(ConnectionError::Protocol(
655 5 : ProtocolError::Protocol("EOF during auth".to_string()),
656 5 : )));
657 : }
658 : }
659 13802 : }
660 :
661 14012 : Ok(())
662 14018 : }
663 :
664 : /// Process startup packet:
665 : /// - transition to Established if auth type is trust
666 : /// - transition to Authentication if auth type is NeonJWT.
667 : /// - or perform TLS handshake -- then need to call this again to receive
668 : /// actual startup packet.
669 26003 : async fn process_startup_message(
670 26003 : &mut self,
671 26003 : handler: &mut impl Handler<IO>,
672 26003 : msg: FeStartupPacket,
673 26003 : ) -> Result<(), QueryError> {
674 26003 : assert!(self.state < ProtoState::Authentication);
675 26003 : let have_tls = self.tls_config.is_some();
676 26003 : match msg {
677 : FeStartupPacket::SslRequest => {
678 0 : debug!("SSL requested");
679 :
680 11985 : self.write_message(&BeMessage::EncryptionResponse(have_tls))
681 0 : .await?;
682 :
683 11985 : if have_tls {
684 4 : self.start_tls().await?;
685 2 : self.state = ProtoState::Encrypted;
686 11983 : }
687 : }
688 : FeStartupPacket::GssEncRequest => {
689 0 : debug!("GSS requested");
690 0 : self.write_message(&BeMessage::EncryptionResponse(false))
691 0 : .await?;
692 : }
693 : FeStartupPacket::StartupMessage { .. } => {
694 14018 : if have_tls && !matches!(self.state, ProtoState::Encrypted) {
695 0 : self.write_message(&BeMessage::ErrorResponse("must connect with TLS", None))
696 0 : .await?;
697 0 : return Err(QueryError::Other(anyhow::anyhow!(
698 0 : "client did not connect with TLS"
699 0 : )));
700 14018 : }
701 14018 :
702 14018 : // NB: startup() may change self.auth_type -- we are using that in proxy code
703 14018 : // to bypass auth for new users.
704 14018 : handler.startup(self, &msg)?;
705 :
706 14018 : match self.auth_type {
707 : AuthType::Trust => {
708 13802 : self.write_message_noflush(&BeMessage::AuthenticationOk)?
709 13802 : .write_message_noflush(&BeMessage::CLIENT_ENCODING)?
710 13802 : .write_message_noflush(&BeMessage::INTEGER_DATETIMES)?
711 : // The async python driver requires a valid server_version
712 13802 : .write_message_noflush(&BeMessage::server_version("14.1"))?
713 13802 : .write_message(&BeMessage::ReadyForQuery)
714 0 : .await?;
715 13802 : self.state = ProtoState::Established;
716 : }
717 : AuthType::NeonJWT => {
718 216 : self.write_message(&BeMessage::AuthenticationCleartextPassword)
719 0 : .await?;
720 216 : self.state = ProtoState::Authentication;
721 : }
722 : }
723 : }
724 : FeStartupPacket::CancelRequest { .. } => {
725 0 : return Err(QueryError::Other(anyhow::anyhow!(
726 0 : "Unexpected CancelRequest message during handshake"
727 0 : )));
728 : }
729 : }
730 26003 : Ok(())
731 26003 : }
732 :
733 20619 : async fn process_message(
734 20619 : &mut self,
735 20619 : handler: &mut impl Handler<IO>,
736 20619 : msg: FeMessage,
737 20619 : unnamed_query_string: &mut Bytes,
738 20619 : ) -> Result<ProcessMsgResult, QueryError> {
739 20619 : // Allow only startup and password messages during auth. Otherwise client would be able to bypass auth
740 20619 : // TODO: change that to proper top-level match of protocol state with separate message handling for each state
741 20619 : assert!(self.state == ProtoState::Established);
742 :
743 20619 : match msg {
744 14154 : FeMessage::Query(body) => {
745 : // remove null terminator
746 14154 : let query_string = cstr_to_str(&body)?;
747 :
748 0 : trace!("got query {query_string:?}");
749 13999059 : if let Err(e) = handler.process_query(self, query_string).await {
750 318 : match e {
751 183 : QueryError::Shutdown => return Ok(ProcessMsgResult::Break),
752 : QueryError::SimulatedConnectionError => {
753 2 : return Err(QueryError::SimulatedConnectionError)
754 : }
755 133 : e => {
756 133 : log_query_error(query_string, &e);
757 133 : let short_error = short_error(&e);
758 133 : self.write_message_noflush(&BeMessage::ErrorResponse(
759 133 : &short_error,
760 133 : Some(e.pg_error_code()),
761 133 : ))?;
762 : }
763 : }
764 13392 : }
765 13524 : self.write_message_noflush(&BeMessage::ReadyForQuery)?;
766 : }
767 :
768 632 : FeMessage::Parse(m) => {
769 632 : *unnamed_query_string = m.query_string;
770 632 : self.write_message_noflush(&BeMessage::ParseComplete)?;
771 : }
772 :
773 : FeMessage::Describe(_) => {
774 632 : self.write_message_noflush(&BeMessage::ParameterDescription)?
775 632 : .write_message_noflush(&BeMessage::NoData)?;
776 : }
777 :
778 : FeMessage::Bind(_) => {
779 632 : self.write_message_noflush(&BeMessage::BindComplete)?;
780 : }
781 :
782 : FeMessage::Close(_) => {
783 631 : self.write_message_noflush(&BeMessage::CloseComplete)?;
784 : }
785 :
786 : FeMessage::Execute(_) => {
787 632 : let query_string = cstr_to_str(unnamed_query_string)?;
788 0 : trace!("got execute {query_string:?}");
789 23353 : if let Err(e) = handler.process_query(self, query_string).await {
790 48 : log_query_error(query_string, &e);
791 48 : self.write_message_noflush(&BeMessage::ErrorResponse(
792 48 : &e.to_string(),
793 48 : Some(e.pg_error_code()),
794 48 : ))?;
795 584 : }
796 : // NOTE there is no ReadyForQuery message. This handler is used
797 : // for basebackup and it uses CopyOut which doesn't require
798 : // ReadyForQuery message and backend just switches back to
799 : // processing mode after sending CopyDone or ErrorResponse.
800 : }
801 :
802 : FeMessage::Sync => {
803 1906 : self.write_message_noflush(&BeMessage::ReadyForQuery)?;
804 : }
805 :
806 : FeMessage::Terminate => {
807 1343 : return Ok(ProcessMsgResult::Break);
808 : }
809 :
810 : // We prefer explicit pattern matching to wildcards, because
811 : // this helps us spot the places where new variants are missing
812 : FeMessage::CopyData(_)
813 : | FeMessage::CopyDone
814 : | FeMessage::CopyFail
815 : | FeMessage::PasswordMessage(_) => {
816 57 : return Err(QueryError::Other(anyhow::anyhow!(
817 57 : "unexpected message type: {msg:?}",
818 57 : )));
819 : }
820 : }
821 :
822 18589 : Ok(ProcessMsgResult::Continue)
823 20174 : }
824 :
825 : /// Log as info/error result of handling COPY stream and send back
826 : /// ErrorResponse if that makes sense. Shutdown the stream if we got
827 : /// Terminate. TODO: transition into waiting for Sync msg if we initiate the
828 : /// close.
829 2183 : pub async fn handle_copy_stream_end(&mut self, end: CopyStreamHandlerEnd) {
830 : use CopyStreamHandlerEnd::*;
831 :
832 2183 : let expected_end = match &end {
833 1957 : ServerInitiated(_) | CopyDone | CopyFail | Terminate | EOF => true,
834 223 : CopyStreamHandlerEnd::Disconnected(ConnectionError::Io(io_error))
835 223 : if is_expected_io_error(io_error) =>
836 223 : {
837 223 : true
838 : }
839 3 : _ => false,
840 : };
841 2183 : if expected_end {
842 2180 : info!("terminated: {:#}", end);
843 : } else {
844 3 : error!("terminated: {:?}", end);
845 : }
846 :
847 : // Note: no current usages ever send this
848 2183 : if let CopyDone = &end {
849 0 : if let Err(e) = self.write_message(&BeMessage::CopyDone).await {
850 0 : error!("failed to send CopyDone: {}", e);
851 0 : }
852 2183 : }
853 :
854 2183 : if let Terminate = &end {
855 25 : self.state = ProtoState::Closed;
856 2158 : }
857 :
858 2183 : let err_to_send_and_errcode = match &end {
859 54 : ServerInitiated(_) => Some((end.to_string(), SQLSTATE_SUCCESSFUL_COMPLETION)),
860 3 : Other(_) => Some((format!("{end:#}"), SQLSTATE_INTERNAL_ERROR)),
861 : // Note: CopyFail in duplex copy is somewhat unexpected (at least to
862 : // PG walsender; evidently and per my docs reading client should
863 : // finish it with CopyDone). It is not a problem to recover from it
864 : // finishing the stream in both directions like we do, but note that
865 : // sync rust-postgres client (which we don't use anymore) hangs if
866 : // socket is not closed here.
867 : // https://github.com/sfackler/rust-postgres/issues/755
868 : // https://github.com/neondatabase/neon/issues/935
869 : //
870 : // Currently, the version of tokio_postgres replication patch we use
871 : // sends this when it closes the stream (e.g. pageserver decided to
872 : // switch conn to another safekeeper and client gets dropped).
873 : // Moreover, seems like 'connection' task errors with 'unexpected
874 : // message from server' when it receives ErrorResponse (anything but
875 : // CopyData/CopyDone) back.
876 30 : CopyFail => Some((end.to_string(), SQLSTATE_SUCCESSFUL_COMPLETION)),
877 2096 : _ => None,
878 : };
879 2183 : if let Some((err, errcode)) = err_to_send_and_errcode {
880 87 : if let Err(ee) = self
881 87 : .write_message(&BeMessage::ErrorResponse(&err, Some(errcode)))
882 1 : .await
883 : {
884 1 : error!("failed to send ErrorResponse: {}", ee);
885 86 : }
886 2096 : }
887 2183 : }
888 : }
889 :
890 : pub struct PostgresBackendReader<IO> {
891 : reader: FramedReader<MaybeTlsStream<IO>>,
892 : closed: bool, // true if received error closing the connection
893 : }
894 :
895 : impl<IO: AsyncRead + AsyncWrite + Unpin> PostgresBackendReader<IO> {
896 : /// Read full message or return None if connection is cleanly closed with no
897 : /// unprocessed data.
898 3472140 : pub async fn read_message(&mut self) -> Result<Option<FeMessage>, ConnectionError> {
899 6573318 : match self.reader.read_message().await {
900 3471431 : Ok(m) => {
901 0 : trace!("read msg {:?}", m);
902 3471431 : Ok(m)
903 : }
904 214 : Err(e) => {
905 214 : self.closed = true;
906 214 : Err(e)
907 : }
908 : }
909 3471645 : }
910 :
911 : /// Get CopyData contents of the next message in COPY stream or error
912 : /// closing it. The error type is wider than actual errors which can happen
913 : /// here -- it includes 'Other' and 'ServerInitiated', but that's ok for
914 : /// current callers.
915 3472140 : pub async fn read_copy_message(&mut self) -> Result<Bytes, CopyStreamHandlerEnd> {
916 6573318 : match self.read_message().await? {
917 3469583 : Some(msg) => match msg {
918 3469528 : FeMessage::CopyData(m) => Ok(m),
919 0 : FeMessage::CopyDone => Err(CopyStreamHandlerEnd::CopyDone),
920 30 : FeMessage::CopyFail => Err(CopyStreamHandlerEnd::CopyFail),
921 25 : FeMessage::Terminate => Err(CopyStreamHandlerEnd::Terminate),
922 0 : _ => Err(CopyStreamHandlerEnd::from(ConnectionError::Protocol(
923 0 : ProtocolError::Protocol(format!("unexpected message in COPY stream {:?}", msg)),
924 0 : ))),
925 : },
926 1848 : None => Err(CopyStreamHandlerEnd::EOF),
927 : }
928 3471645 : }
929 : }
930 :
931 : ///
932 : /// A futures::AsyncWrite implementation that wraps all data written to it in CopyData
933 : /// messages.
934 : ///
935 :
936 : pub struct CopyDataWriter<'a, IO> {
937 : pgb: &'a mut PostgresBackend<IO>,
938 : }
939 :
940 : impl<'a, IO: AsyncRead + AsyncWrite + Unpin> AsyncWrite for CopyDataWriter<'a, IO> {
941 983738 : fn poll_write(
942 983738 : self: Pin<&mut Self>,
943 983738 : cx: &mut std::task::Context<'_>,
944 983738 : buf: &[u8],
945 983738 : ) -> Poll<Result<usize, std::io::Error>> {
946 983738 : let this = self.get_mut();
947 :
948 : // It's not strictly required to flush between each message, but makes it easier
949 : // to view in wireshark, and usually the messages that the callers write are
950 : // decently-sized anyway.
951 983738 : if let Err(err) = ready!(this.pgb.poll_flush(cx)) {
952 0 : return Poll::Ready(Err(err));
953 975476 : }
954 975476 :
955 975476 : // CopyData
956 975476 : // XXX: if the input is large, we should split it into multiple messages.
957 975476 : // Not sure what the threshold should be, but the ultimate hard limit is that
958 975476 : // the length cannot exceed u32.
959 975476 : this.pgb
960 975476 : .write_message_noflush(&BeMessage::CopyData(buf))
961 975476 : // write_message only writes to the buffer, so it can fail iff the
962 975476 : // message is invaid, but CopyData can't be invalid.
963 975476 : .map_err(|_| io::Error::new(ErrorKind::Other, "failed to serialize CopyData"))?;
964 :
965 975476 : Poll::Ready(Ok(buf.len()))
966 983738 : }
967 :
968 40499 : fn poll_flush(
969 40499 : self: Pin<&mut Self>,
970 40499 : cx: &mut std::task::Context<'_>,
971 40499 : ) -> Poll<Result<(), std::io::Error>> {
972 40499 : let this = self.get_mut();
973 40499 : this.pgb.poll_flush(cx)
974 40499 : }
975 :
976 170 : fn poll_shutdown(
977 170 : self: Pin<&mut Self>,
978 170 : cx: &mut std::task::Context<'_>,
979 170 : ) -> Poll<Result<(), std::io::Error>> {
980 170 : let this = self.get_mut();
981 170 : this.pgb.poll_flush(cx)
982 170 : }
983 : }
984 :
985 133 : pub fn short_error(e: &QueryError) -> String {
986 133 : match e {
987 116 : QueryError::Disconnected(connection_error) => connection_error.to_string(),
988 0 : QueryError::Reconnect => "reconnect".to_string(),
989 0 : QueryError::Shutdown => "shutdown".to_string(),
990 12 : QueryError::NotFound(_) => "not found".to_string(),
991 5 : QueryError::Unauthorized(_e) => "JWT authentication error".to_string(),
992 0 : QueryError::SimulatedConnectionError => "simulated connection error".to_string(),
993 0 : QueryError::Other(e) => format!("{e:#}"),
994 : }
995 133 : }
996 :
997 181 : fn log_query_error(query: &str, e: &QueryError) {
998 116 : match e {
999 116 : QueryError::Disconnected(ConnectionError::Io(io_error)) => {
1000 116 : if is_expected_io_error(io_error) {
1001 116 : info!("query handler for '{query}' failed with expected io error: {io_error}");
1002 : } else {
1003 0 : error!("query handler for '{query}' failed with io error: {io_error}");
1004 : }
1005 : }
1006 0 : QueryError::Disconnected(other_connection_error) => {
1007 0 : error!("query handler for '{query}' failed with connection error: {other_connection_error:?}")
1008 : }
1009 : QueryError::SimulatedConnectionError => {
1010 0 : error!("query handler for query '{query}' failed due to a simulated connection error")
1011 : }
1012 : QueryError::Reconnect => {
1013 0 : info!("query handler for '{query}' requested client to reconnect")
1014 : }
1015 : QueryError::Shutdown => {
1016 0 : info!("query handler for '{query}' cancelled during tenant shutdown")
1017 : }
1018 18 : QueryError::NotFound(reason) => {
1019 18 : info!("query handler for '{query}' entity not found: {reason}")
1020 : }
1021 4 : QueryError::Unauthorized(e) => {
1022 4 : warn!("query handler for '{query}' failed with authentication error: {e}");
1023 : }
1024 43 : QueryError::Other(e) => {
1025 43 : error!("query handler for '{query}' failed: {e:?}");
1026 : }
1027 : }
1028 181 : }
1029 :
1030 : /// Something finishing handling of COPY stream, see handle_copy_stream_end.
1031 : /// This is not always a real error, but it allows to use ? and thiserror impls.
1032 2267 : #[derive(thiserror::Error, Debug)]
1033 : pub enum CopyStreamHandlerEnd {
1034 : /// Handler initiates the end of streaming.
1035 : #[error("{0}")]
1036 : ServerInitiated(String),
1037 : #[error("received CopyDone")]
1038 : CopyDone,
1039 : #[error("received CopyFail")]
1040 : CopyFail,
1041 : #[error("received Terminate")]
1042 : Terminate,
1043 : #[error("EOF on COPY stream")]
1044 : EOF,
1045 : /// The connection was lost
1046 : #[error("connection error: {0}")]
1047 : Disconnected(#[from] ConnectionError),
1048 : /// Some other error
1049 : #[error(transparent)]
1050 : Other(#[from] anyhow::Error),
1051 : }
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