1 files changed, 333 insertions, 0 deletions
diff --git a/ext/http/websocket_upgrade.rs b/ext/http/websocket_upgrade.rs
new file mode 100644
index 000000000..042a46721
--- /dev/null
+++ b/ext/http/websocket_upgrade.rs
@@ -0,0 +1,333 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use bytes::Bytes;
+use bytes::BytesMut;
+use deno_core::error::AnyError;
+use httparse::Status;
+use hyper::http::HeaderName;
+use hyper::http::HeaderValue;
+use hyper::Body;
+use hyper::Response;
+use memmem::Searcher;
+use memmem::TwoWaySearcher;
+use once_cell::sync::OnceCell;
+
+use crate::http_error;
+
+/// Given a buffer that ends in `\n\n` or `\r\n\r\n`, returns a parsed [`Request<Body>`].
+fn parse_response(
+  header_bytes: &[u8],
+) -> Result<(usize, Response<Body>), AnyError> {
+  let mut headers = [httparse::EMPTY_HEADER; 16];
+  let status = httparse::parse_headers(header_bytes, &mut headers)?;
+  match status {
+    Status::Complete((index, parsed)) => {
+      let mut resp = Response::builder().status(101).body(Body::empty())?;
+      for header in parsed.iter() {
+        resp.headers_mut().append(
+          HeaderName::from_bytes(header.name.as_bytes())?,
+          HeaderValue::from_str(std::str::from_utf8(header.value)?)?,
+        );
+      }
+      Ok((index, resp))
+    }
+    _ => Err(http_error("invalid headers")),
+  }
+}
+
+/// Find a newline in a slice.
+fn find_newline(slice: &[u8]) -> Option<usize> {
+  for (i, byte) in slice.iter().enumerate() {
+    if *byte == b'\n' {
+      return Some(i);
+    }
+  }
+  None
+}
+
+/// WebSocket upgrade state machine states.
+#[derive(Default)]
+enum WebSocketUpgradeState {
+  #[default]
+  Initial,
+  StatusLine,
+  Headers,
+  Complete,
+}
+
+static HEADER_SEARCHER: OnceCell<TwoWaySearcher> = OnceCell::new();
+static HEADER_SEARCHER2: OnceCell<TwoWaySearcher> = OnceCell::new();
+
+#[derive(Default)]
+pub struct WebSocketUpgrade {
+  state: WebSocketUpgradeState,
+  buf: BytesMut,
+}
+
+impl WebSocketUpgrade {
+  /// Ensures that the status line starts with "HTTP/1.1 101 " which matches all of the node.js
+  /// WebSocket libraries that are known. We don't care about the trailing status text.
+  fn validate_status(&self, status: &[u8]) -> Result<(), AnyError> {
+    if status.starts_with(b"HTTP/1.1 101 ") {
+      Ok(())
+    } else {
+      Err(http_error("invalid HTTP status line"))
+    }
+  }
+
+  /// Writes bytes to our upgrade buffer, returning [`Ok(None)`] if we need to keep feeding it data,
+  /// [`Ok(Some(Response))`] if we got a valid upgrade header, or [`Err`] if something went badly.
+  pub fn write(
+    &mut self,
+    bytes: &[u8],
+  ) -> Result<Option<(Response<Body>, Bytes)>, AnyError> {
+    use WebSocketUpgradeState::*;
+
+    match self.state {
+      Initial => {
+        if let Some(index) = find_newline(bytes) {
+          let (status, rest) = bytes.split_at(index + 1);
+          self.validate_status(status)?;
+
+          // Fast path for the most common node.js WebSocket libraries that use \r\n as the
+          // separator between header lines and send the whole response in one packet.
+          if rest.ends_with(b"\r\n\r\n") {
+            let (index, response) = parse_response(rest)?;
+            if index == rest.len() {
+              return Ok(Some((response, Bytes::default())));
+            } else {
+              let bytes = Bytes::copy_from_slice(&rest[index..]);
+              return Ok(Some((response, bytes)));
+            }
+          }
+
+          self.state = Headers;
+          self.write(rest)
+        } else {
+          self.state = StatusLine;
+          self.buf.extend_from_slice(bytes);
+          Ok(None)
+        }
+      }
+      StatusLine => {
+        if let Some(index) = find_newline(bytes) {
+          let (status, rest) = bytes.split_at(index + 1);
+          self.buf.extend_from_slice(status);
+          self.validate_status(&self.buf)?;
+          self.buf.clear();
+          // Recursively process this write
+          self.state = Headers;
+          self.write(rest)
+        } else {
+          self.buf.extend_from_slice(bytes);
+          Ok(None)
+        }
+      }
+      Headers => {
+        self.buf.extend_from_slice(bytes);
+        let header_searcher =
+          HEADER_SEARCHER.get_or_init(|| TwoWaySearcher::new(b"\r\n\r\n"));
+        let header_searcher2 =
+          HEADER_SEARCHER2.get_or_init(|| TwoWaySearcher::new(b"\n\n"));
+        if let Some(..) = header_searcher.search_in(&self.buf) {
+          let (index, response) = parse_response(&self.buf)?;
+          let mut buf = std::mem::take(&mut self.buf);
+          self.state = Complete;
+          Ok(Some((response, buf.split_off(index).freeze())))
+        } else if let Some(..) = header_searcher2.search_in(&self.buf) {
+          let (index, response) = parse_response(&self.buf)?;
+          let mut buf = std::mem::take(&mut self.buf);
+          self.state = Complete;
+          Ok(Some((response, buf.split_off(index).freeze())))
+        } else {
+          Ok(None)
+        }
+      }
+      Complete => {
+        Err(http_error("attempted to write to completed upgrade buffer"))
+      }
+    }
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  type ExpectedResponseAndHead = Option<(Response<Body>, &'static [u8])>;
+
+  fn assert_response(
+    result: Result<Option<(Response<Body>, Bytes)>, AnyError>,
+    expected: Result<ExpectedResponseAndHead, &'static str>,
+    chunk_info: Option<(usize, usize)>,
+  ) {
+    let formatted = format!("{result:?}");
+    match expected {
+      Ok(Some((resp1, remainder1))) => match result {
+        Ok(Some((resp2, remainder2))) => {
+          assert_eq!(format!("{resp1:?}"), format!("{resp2:?}"));
+          if let Some((byte_len, chunk_size)) = chunk_info {
+            // We need to compute how many bytes should be in the trailing data
+
+            // We know how many bytes of header data we had
+            let last_packet_header_size =
+              (byte_len - remainder1.len() + chunk_size - 1) % chunk_size + 1;
+
+            // Which means we can compute how much was in the remainder
+            let remaining =
+              (chunk_size - last_packet_header_size).min(remainder1.len());
+
+            assert_eq!(remainder1[..remaining], remainder2);
+          } else {
+            assert_eq!(remainder1, remainder2);
+          }
+        }
+        _ => panic!("Expected Ok(Some(...)), was {formatted}"),
+      },
+      Ok(None) => assert!(
+        result.ok().unwrap().is_none(),
+        "Expected Ok(None), was {formatted}",
+      ),
+      Err(e) => assert_eq!(
+        e,
+        result.err().map(|e| format!("{e:?}")).unwrap_or_default(),
+        "Expected error, was {formatted}",
+      ),
+    }
+  }
+
+  fn validate_upgrade_all_at_once(
+    s: &str,
+    expected: Result<ExpectedResponseAndHead, &'static str>,
+  ) {
+    let mut upgrade = WebSocketUpgrade::default();
+    let res = upgrade.write(s.as_bytes());
+
+    assert_response(res, expected, None);
+  }
+
+  fn validate_upgrade_chunks(
+    s: &str,
+    size: usize,
+    expected: Result<ExpectedResponseAndHead, &'static str>,
+  ) {
+    let chunk_info = Some((s.as_bytes().len(), size));
+    let mut upgrade = WebSocketUpgrade::default();
+    let mut result = Ok(None);
+    for chunk in s.as_bytes().chunks(size) {
+      result = upgrade.write(chunk);
+      if let Ok(Some(..)) = &result {
+        assert_response(result, expected, chunk_info);
+        return;
+      }
+    }
+    assert_response(result, expected, chunk_info);
+  }
+
+  fn validate_upgrade(
+    s: &str,
+    expected: fn() -> Result<ExpectedResponseAndHead, &'static str>,
+  ) {
+    validate_upgrade_all_at_once(s, expected());
+    validate_upgrade_chunks(s, 1, expected());
+    validate_upgrade_chunks(s, 2, expected());
+    validate_upgrade_chunks(s, 10, expected());
+
+    // Replace \n with \r\n, but only in headers
+    let (headers, trailing) = s.split_once("\n\n").unwrap();
+    let s = headers.replace('\n', "\r\n") + "\r\n\r\n" + trailing;
+    let s = s.as_ref();
+
+    validate_upgrade_all_at_once(s, expected());
+    validate_upgrade_chunks(s, 1, expected());
+    validate_upgrade_chunks(s, 2, expected());
+    validate_upgrade_chunks(s, 10, expected());
+  }
+
+  #[test]
+  fn upgrade1() {
+    validate_upgrade(
+      "HTTP/1.1 101 Switching Protocols\nConnection: Upgrade\n\n",
+      || {
+        let mut expected =
+          Response::builder().status(101).body(Body::empty()).unwrap();
+        expected.headers_mut().append(
+          HeaderName::from_static("connection"),
+          HeaderValue::from_static("Upgrade"),
+        );
+        Ok(Some((expected, b"")))
+      },
+    );
+  }
+
+  #[test]
+  fn upgrade_trailing() {
+    validate_upgrade(
+      "HTTP/1.1 101 Switching Protocols\nConnection: Upgrade\n\ntrailing data",
+      || {
+        let mut expected =
+          Response::builder().status(101).body(Body::empty()).unwrap();
+        expected.headers_mut().append(
+          HeaderName::from_static("connection"),
+          HeaderValue::from_static("Upgrade"),
+        );
+        Ok(Some((expected, b"trailing data")))
+      },
+    );
+  }
+
+  #[test]
+  fn upgrade_trailing_with_newlines() {
+    validate_upgrade(
+      "HTTP/1.1 101 Switching Protocols\nConnection: Upgrade\n\ntrailing data\r\n\r\n",
+      || {
+        let mut expected =
+          Response::builder().status(101).body(Body::empty()).unwrap();
+        expected.headers_mut().append(
+          HeaderName::from_static("connection"),
+          HeaderValue::from_static("Upgrade"),
+        );
+        Ok(Some((expected, b"trailing data\r\n\r\n")))
+      },
+    );
+  }
+
+  #[test]
+  fn upgrade2() {
+    validate_upgrade(
+      "HTTP/1.1 101 Switching Protocols\nConnection: Upgrade\nOther: 123\n\n",
+      || {
+        let mut expected =
+          Response::builder().status(101).body(Body::empty()).unwrap();
+        expected.headers_mut().append(
+          HeaderName::from_static("connection"),
+          HeaderValue::from_static("Upgrade"),
+        );
+        expected.headers_mut().append(
+          HeaderName::from_static("other"),
+          HeaderValue::from_static("123"),
+        );
+        Ok(Some((expected, b"")))
+      },
+    );
+  }
+
+  #[test]
+  fn upgrade_invalid_status() {
+    validate_upgrade("HTTP/1.1 200 OK\nConnection: Upgrade\n\n", || {
+      Err("invalid HTTP status line")
+    });
+  }
+
+  #[test]
+  fn upgrade_too_many_headers() {
+    let headers = (0..20)
+      .map(|i| format!("h{i}: {i}"))
+      .collect::<Vec<_>>()
+      .join("\n");
+    validate_upgrade(
+      &format!("HTTP/1.1 101 Switching Protocols\n{headers}\n\n"),
+      || Err("too many headers"),
+    );
+  }
+}