tor_proto/stream/
resolve.rs

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1//! Declare a type for streams that do hostname lookups
2
3use crate::memquota::StreamAccount;
4use crate::stream::StreamReader;
5use crate::{Error, Result};
6use tor_cell::relaycell::msg::Resolved;
7use tor_cell::relaycell::RelayCmd;
8use tor_cell::restricted_msg;
9
10use super::AnyCmdChecker;
11
12/// A ResolveStream represents a pending DNS request made with a RESOLVE
13/// cell.
14pub struct ResolveStream {
15    /// The underlying RawCellStream.
16    s: StreamReader,
17
18    /// The memory quota account that should be used for this "stream"'s data
19    ///
20    /// Exists to keep the account alive
21    _memquota: StreamAccount,
22}
23
24restricted_msg! {
25    /// An allowable reply for a RESOLVE message.
26    enum ResolveResponseMsg : RelayMsg {
27        End,
28        Resolved,
29    }
30}
31
32impl ResolveStream {
33    /// Wrap a RawCellStream into a ResolveStream.
34    ///
35    /// Call only after sending a RESOLVE cell.
36    pub(crate) fn new(s: StreamReader, memquota: StreamAccount) -> Self {
37        ResolveStream {
38            s,
39            _memquota: memquota,
40        }
41    }
42
43    /// Read a message from this stream telling us the answer to our
44    /// name lookup request.
45    pub async fn read_msg(&mut self) -> Result<Resolved> {
46        use ResolveResponseMsg::*;
47        let cell = self.s.recv().await?;
48        let msg = match cell.decode::<ResolveResponseMsg>() {
49            Ok(cell) => cell.into_msg(),
50            Err(e) => {
51                self.s.protocol_error();
52                return Err(Error::from_bytes_err(e, "response on a resolve stream"));
53            }
54        };
55        match msg {
56            End(e) => Err(Error::EndReceived(e.reason())),
57            Resolved(r) => Ok(r),
58        }
59    }
60}
61
62/// A `CmdChecker` that enforces correctness for incoming commands on an
63/// outbound resolve stream.
64#[derive(Debug, Default)]
65pub(crate) struct ResolveCmdChecker {}
66
67impl super::CmdChecker for ResolveCmdChecker {
68    fn check_msg(
69        &mut self,
70        msg: &tor_cell::relaycell::UnparsedRelayMsg,
71    ) -> Result<super::StreamStatus> {
72        use super::StreamStatus::Closed;
73        match msg.cmd() {
74            RelayCmd::RESOLVED => Ok(Closed),
75            RelayCmd::END => Ok(Closed),
76            _ => Err(Error::StreamProto(format!(
77                "Unexpected {} on resolve stream",
78                msg.cmd()
79            ))),
80        }
81    }
82
83    fn consume_checked_msg(&mut self, msg: tor_cell::relaycell::UnparsedRelayMsg) -> Result<()> {
84        let _ = msg
85            .decode::<ResolveResponseMsg>()
86            .map_err(|err| Error::from_bytes_err(err, "message on resolve stream."))?;
87        Ok(())
88    }
89}
90
91impl ResolveCmdChecker {
92    /// Return a new boxed `DataCmdChecker` in a state suitable for a newly
93    /// constructed connection.
94    pub(crate) fn new_any() -> AnyCmdChecker {
95        Box::<Self>::default()
96    }
97}
tor_proto/stream/resolve.rs

tor_proto/stream/
resolve.rs
