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
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
use std::future;
use std::io;
use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};

/// Converts or resolves without blocking to one or more `SocketAddr` values.
///
/// # DNS
///
/// Implementations of `ToSocketAddrs` for string types require a DNS lookup.
///
/// # Calling
///
/// Currently, this trait is only used as an argument to Tokio functions that
/// need to reference a target socket address. To perform a `SocketAddr`
/// conversion directly, use [`lookup_host()`](super::lookup_host()).
///
/// This trait is sealed and is intended to be opaque. The details of the trait
/// will change. Stabilization is pending enhancements to the Rust language.
pub trait ToSocketAddrs: sealed::ToSocketAddrsPriv {}

type ReadyFuture<T> = future::Ready<io::Result<T>>;

cfg_net! {
    pub(crate) fn to_socket_addrs<T>(arg: T) -> T::Future
    where
        T: ToSocketAddrs,
    {
        arg.to_socket_addrs(sealed::Internal)
    }
}

// ===== impl &impl ToSocketAddrs =====

impl<T: ToSocketAddrs + ?Sized> ToSocketAddrs for &T {}

impl<T> sealed::ToSocketAddrsPriv for &T
where
    T: sealed::ToSocketAddrsPriv + ?Sized,
{
    type Iter = T::Iter;
    type Future = T::Future;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        (**self).to_socket_addrs(sealed::Internal)
    }
}

// ===== impl SocketAddr =====

impl ToSocketAddrs for SocketAddr {}

impl sealed::ToSocketAddrsPriv for SocketAddr {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        let iter = Some(*self).into_iter();
        future::ready(Ok(iter))
    }
}

// ===== impl SocketAddrV4 =====

impl ToSocketAddrs for SocketAddrV4 {}

impl sealed::ToSocketAddrsPriv for SocketAddrV4 {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        SocketAddr::V4(*self).to_socket_addrs(sealed::Internal)
    }
}

// ===== impl SocketAddrV6 =====

impl ToSocketAddrs for SocketAddrV6 {}

impl sealed::ToSocketAddrsPriv for SocketAddrV6 {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        SocketAddr::V6(*self).to_socket_addrs(sealed::Internal)
    }
}

// ===== impl (IpAddr, u16) =====

impl ToSocketAddrs for (IpAddr, u16) {}

impl sealed::ToSocketAddrsPriv for (IpAddr, u16) {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        let iter = Some(SocketAddr::from(*self)).into_iter();
        future::ready(Ok(iter))
    }
}

// ===== impl (Ipv4Addr, u16) =====

impl ToSocketAddrs for (Ipv4Addr, u16) {}

impl sealed::ToSocketAddrsPriv for (Ipv4Addr, u16) {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        let (ip, port) = *self;
        SocketAddrV4::new(ip, port).to_socket_addrs(sealed::Internal)
    }
}

// ===== impl (Ipv6Addr, u16) =====

impl ToSocketAddrs for (Ipv6Addr, u16) {}

impl sealed::ToSocketAddrsPriv for (Ipv6Addr, u16) {
    type Iter = std::option::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        let (ip, port) = *self;
        SocketAddrV6::new(ip, port, 0, 0).to_socket_addrs(sealed::Internal)
    }
}

// ===== impl &[SocketAddr] =====

impl ToSocketAddrs for &[SocketAddr] {}

impl sealed::ToSocketAddrsPriv for &[SocketAddr] {
    type Iter = std::vec::IntoIter<SocketAddr>;
    type Future = ReadyFuture<Self::Iter>;

    fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
        // Clippy doesn't like the `to_vec()` call here (as it will allocate,
        // while `self.iter().copied()` would not), but it's actually necessary
        // in order to ensure that the returned iterator is valid for the
        // `'static` lifetime, which the borrowed `slice::Iter` iterator would
        // not be.
        // Note that we can't actually add an `allow` attribute for
        // `clippy::unnecessary_to_owned` here, as Tokio's CI runs clippy lints
        // on Rust 1.52 to avoid breaking LTS releases of Tokio. Users of newer
        // Rust versions who see this lint should just ignore it.
        let iter = self.to_vec().into_iter();
        future::ready(Ok(iter))
    }
}

cfg_net! {
    // ===== impl str =====

    impl ToSocketAddrs for str {}

    impl sealed::ToSocketAddrsPriv for str {
        type Iter = sealed::OneOrMore;
        type Future = sealed::MaybeReady;

        fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
            use crate::blocking::spawn_blocking;
            use sealed::MaybeReady;

            // First check if the input parses as a socket address
            let res: Result<SocketAddr, _> = self.parse();

            if let Ok(addr) = res {
                return MaybeReady(sealed::State::Ready(Some(addr)));
            }

            // Run DNS lookup on the blocking pool
            let s = self.to_owned();

            MaybeReady(sealed::State::Blocking(spawn_blocking(move || {
                std::net::ToSocketAddrs::to_socket_addrs(&s)
            })))
        }
    }

    // ===== impl (&str, u16) =====

    impl ToSocketAddrs for (&str, u16) {}

    impl sealed::ToSocketAddrsPriv for (&str, u16) {
        type Iter = sealed::OneOrMore;
        type Future = sealed::MaybeReady;

        fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
            use crate::blocking::spawn_blocking;
            use sealed::MaybeReady;

            let (host, port) = *self;

            // try to parse the host as a regular IP address first
            if let Ok(addr) = host.parse::<Ipv4Addr>() {
                let addr = SocketAddrV4::new(addr, port);
                let addr = SocketAddr::V4(addr);

                return MaybeReady(sealed::State::Ready(Some(addr)));
            }

            if let Ok(addr) = host.parse::<Ipv6Addr>() {
                let addr = SocketAddrV6::new(addr, port, 0, 0);
                let addr = SocketAddr::V6(addr);

                return MaybeReady(sealed::State::Ready(Some(addr)));
            }

            let host = host.to_owned();

            MaybeReady(sealed::State::Blocking(spawn_blocking(move || {
                std::net::ToSocketAddrs::to_socket_addrs(&(&host[..], port))
            })))
        }
    }

    // ===== impl (String, u16) =====

    impl ToSocketAddrs for (String, u16) {}

    impl sealed::ToSocketAddrsPriv for (String, u16) {
        type Iter = sealed::OneOrMore;
        type Future = sealed::MaybeReady;

        fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
            (self.0.as_str(), self.1).to_socket_addrs(sealed::Internal)
        }
    }

    // ===== impl String =====

    impl ToSocketAddrs for String {}

    impl sealed::ToSocketAddrsPriv for String {
        type Iter = <str as sealed::ToSocketAddrsPriv>::Iter;
        type Future = <str as sealed::ToSocketAddrsPriv>::Future;

        fn to_socket_addrs(&self, _: sealed::Internal) -> Self::Future {
            (&self[..]).to_socket_addrs(sealed::Internal)
        }
    }
}

pub(crate) mod sealed {
    //! The contents of this trait are intended to remain private and __not__
    //! part of the `ToSocketAddrs` public API. The details will change over
    //! time.

    use std::future::Future;
    use std::io;
    use std::net::SocketAddr;

    #[doc(hidden)]
    pub trait ToSocketAddrsPriv {
        type Iter: Iterator<Item = SocketAddr> + Send + 'static;
        type Future: Future<Output = io::Result<Self::Iter>> + Send + 'static;

        fn to_socket_addrs(&self, internal: Internal) -> Self::Future;
    }

    #[allow(missing_debug_implementations)]
    pub struct Internal;

    cfg_net! {
        use crate::blocking::JoinHandle;

        use std::option;
        use std::pin::Pin;
        use std::task::{Context, Poll};
        use std::vec;

        #[doc(hidden)]
        #[derive(Debug)]
        pub struct MaybeReady(pub(super) State);

        #[derive(Debug)]
        pub(super) enum State {
            Ready(Option<SocketAddr>),
            Blocking(JoinHandle<io::Result<vec::IntoIter<SocketAddr>>>),
        }

        #[doc(hidden)]
        #[derive(Debug)]
        pub enum OneOrMore {
            One(option::IntoIter<SocketAddr>),
            More(vec::IntoIter<SocketAddr>),
        }

        impl Future for MaybeReady {
            type Output = io::Result<OneOrMore>;

            fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
                match self.0 {
                    State::Ready(ref mut i) => {
                        let iter = OneOrMore::One(i.take().into_iter());
                        Poll::Ready(Ok(iter))
                    }
                    State::Blocking(ref mut rx) => {
                        let res = ready!(Pin::new(rx).poll(cx))?.map(OneOrMore::More);

                        Poll::Ready(res)
                    }
                }
            }
        }

        impl Iterator for OneOrMore {
            type Item = SocketAddr;

            fn next(&mut self) -> Option<Self::Item> {
                match self {
                    OneOrMore::One(i) => i.next(),
                    OneOrMore::More(i) => i.next(),
                }
            }

            fn size_hint(&self) -> (usize, Option<usize>) {
                match self {
                    OneOrMore::One(i) => i.size_hint(),
                    OneOrMore::More(i) => i.size_hint(),
                }
            }
        }
    }
}