#
actix_tls/connect/
resolver.rs

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201

    use std::{
        future::Future,
        io,
        net::SocketAddr,
        pin::Pin,
        rc::Rc,
        task::{Context, Poll},
        vec::IntoIter,
    };

    use actix_rt::task::{spawn_blocking, JoinHandle};
    use actix_service::{Service, ServiceFactory};
    use actix_utils::future::{ok, Ready};
    use futures_core::{future::LocalBoxFuture, ready};
    use tracing::trace;

    use super::{ConnectError, ConnectInfo, Host, Resolve};

    /// DNS resolver service factory.
    #[derive(Clone, Default)]
    pub struct Resolver {
        resolver: ResolverService,
    }

    impl Resolver {
        /// Constructs a new resolver factory with a custom resolver.
        pub fn custom(resolver: impl Resolve + 'static) -> Self {
            Self {
                resolver: ResolverService::custom(resolver),
            }
        }

        /// Returns a new resolver service.
        pub fn service(&self) -> ResolverService {
            self.resolver.clone()
        }
    }

    impl<R: Host> ServiceFactory<ConnectInfo<R>> for Resolver {
        type Response = ConnectInfo<R>;
        type Error = ConnectError;
        type Config = ();
        type Service = ResolverService;
        type InitError = ();
        type Future = Ready<Result<Self::Service, Self::InitError>>;

        fn new_service(&self, _: ()) -> Self::Future {
            ok(self.resolver.clone())
        }
    }

    #[derive(Clone)]
    enum ResolverKind {
        /// Built-in DNS resolver.
        ///
        /// See [`std::net::ToSocketAddrs`] trait.
        Default,

        /// Custom, user-provided DNS resolver.
        Custom(Rc<dyn Resolve>),
    }

    impl Default for ResolverKind {
        fn default() -> Self {
            Self::Default
        }
    }

    /// DNS resolver service.
    #[derive(Clone, Default)]
    pub struct ResolverService {
        kind: ResolverKind,
    }

    impl ResolverService {
        /// Constructor for custom Resolve trait object and use it as resolver.
        pub fn custom(resolver: impl Resolve + 'static) -> Self {
            Self {
                kind: ResolverKind::Custom(Rc::new(resolver)),
            }
        }

        /// Resolve DNS with default resolver.
        fn default_lookup<R: Host>(
            req: &ConnectInfo<R>,
        ) -> JoinHandle<io::Result<IntoIter<SocketAddr>>> {
            // reconstruct host; concatenate hostname and port together
            let host = format!("{}:{}", req.hostname(), req.port());

            // run blocking DNS lookup in thread pool since DNS lookups can take upwards of seconds on
            // some platforms if conditions are poor and OS-level cache is not populated
            spawn_blocking(move || std::net::ToSocketAddrs::to_socket_addrs(&host))
        }
    }

    impl<R: Host> Service<ConnectInfo<R>> for ResolverService {
        type Response = ConnectInfo<R>;
        type Error = ConnectError;
        type Future = ResolverFut<R>;

        actix_service::always_ready!();

        fn call(&self, req: ConnectInfo<R>) -> Self::Future {
            if req.addr.is_resolved() {
                // socket address(es) already resolved; return existing connection request
                ResolverFut::Resolved(Some(req))
            } else if let Ok(ip) = req.hostname().parse() {
                // request hostname is valid ip address; add address to request and return
                let addr = SocketAddr::new(ip, req.port());
                let req = req.set_addr(Some(addr));
                ResolverFut::Resolved(Some(req))
            } else {
                trace!("DNS resolver: resolving host {:?}", req.hostname());

                match &self.kind {
                    ResolverKind::Default => {
                        let fut = Self::default_lookup(&req);
                        ResolverFut::LookUp(fut, Some(req))
                    }

                    ResolverKind::Custom(resolver) => {
                        let resolver = Rc::clone(resolver);

                        ResolverFut::LookupCustom(Box::pin(async move {
                            let addrs = resolver
                                .lookup(req.hostname(), req.port())
                                .await
                                .map_err(ConnectError::Resolver)?;

                            let req = req.set_addrs(addrs);

                            if req.addr.is_unresolved() {
                                Err(ConnectError::NoRecords)
                            } else {
                                Ok(req)
                            }
                        }))
                    }
                }
            }
        }
    }

    /// Future for resolver service.
    #[doc(hidden)]
    pub enum ResolverFut<R: Host> {
        Resolved(Option<ConnectInfo<R>>),
        LookUp(
            JoinHandle<io::Result<IntoIter<SocketAddr>>>,
            Option<ConnectInfo<R>>,
        ),
        LookupCustom(LocalBoxFuture<'static, Result<ConnectInfo<R>, ConnectError>>),
    }

    impl<R: Host> Future for ResolverFut<R> {
        type Output = Result<ConnectInfo<R>, ConnectError>;

        fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
            match self.get_mut() {
                Self::Resolved(conn) => Poll::Ready(Ok(conn
                    .take()
                    .expect("ResolverFuture polled after finished"))),

                Self::LookUp(fut, req) => {
                    let res = match ready!(Pin::new(fut).poll(cx)) {
                        Ok(Ok(res)) => Ok(res),
                        Ok(Err(err)) => Err(ConnectError::Resolver(Box::new(err))),
                        Err(err) => Err(ConnectError::Io(err.into())),
                    };

                    let req = req.take().unwrap();

                    let addrs = res.map_err(|err| {
                        trace!(
                            "DNS resolver: failed to resolve host {:?} err: {:?}",
                            req.hostname(),
                            err
                        );

                        err
                    })?;

                    let req = req.set_addrs(addrs);

                    trace!(
                        "DNS resolver: host {:?} resolved to {:?}",
                        req.hostname(),
                        req.addrs()
                    );

                    if req.addr.is_unresolved() {
                        Poll::Ready(Err(ConnectError::NoRecords))
                    } else {
                        Poll::Ready(Ok(req))
                    }
                }

                Self::LookupCustom(fut) => fut.as_mut().poll(cx),
            }
        }
    }