1 // Copyright (c) 2023 Huawei Device Co., Ltd.
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
4 // You may obtain a copy of the License at
5 //
6 //     http://www.apache.org/licenses/LICENSE-2.0
7 //
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13 
14 //! `Resolver` trait and `DefaultDnsResolver` implementation.
15 
16 use std::future::Future;
17 use std::io;
18 use std::io::Error;
19 use std::net::{SocketAddr, ToSocketAddrs};
20 use std::pin::Pin;
21 use std::task::{Context, Poll};
22 use std::vec::IntoIter;
23 
24 use crate::runtime::JoinHandle;
25 
26 /// `SocketAddr` resolved by `Resolver`.
27 pub type Addrs = Box<dyn Iterator<Item = SocketAddr> + Sync + Send>;
28 /// Possible errors that this resolver may generate when attempting to
29 /// resolve.
30 pub type StdError = Box<dyn std::error::Error + Send + Sync>;
31 /// Futures generated by this resolve when attempting to resolve an address.
32 pub type SocketFuture = Pin<Box<dyn Future<Output = Result<Addrs, StdError>> + Sync + Send>>;
33 
34 /// `Resolver` trait used by `async_impl::connector::HttpConnector`. `Resolver`
35 /// provides asynchronous dns resolve interfaces.
36 pub trait Resolver: Send + Sync + 'static {
37     /// resolve domain to a `SocketAddr` `Future`.
resolvenull38     fn resolve(&self, domain: &str) -> SocketFuture;
39 }
40 
41 /// `SocketAddr` resolved by `DefaultDnsResolver`.
42 pub struct ResolvedAddrs {
43     iter: IntoIter<SocketAddr>,
44 }
45 
46 impl ResolvedAddrs {
47     pub(super) fn new(iter: IntoIter<SocketAddr>) -> Self {
48         Self { iter }
49     }
50 
51     // The first ip in the dns record is the preferred addrs type.
52     pub(super) fn split_preferred_addrs(self) -> (Vec<SocketAddr>, Vec<SocketAddr>) {
53         // get preferred address family type.
54         let is_ipv6 = self
55             .iter
56             .as_slice()
57             .first()
58             .map(SocketAddr::is_ipv6)
59             .unwrap_or(false);
60         self.iter
61             .partition::<Vec<_>, _>(|addr| addr.is_ipv6() == is_ipv6)
62     }
63 }
64 
65 impl Iterator for ResolvedAddrs {
66     type Item = SocketAddr;
67 
nextnull68     fn next(&mut self) -> Option<Self::Item> {
69         self.iter.next()
70     }
71 }
72 
73 /// Futures generated by `DefaultDnsResolver`.
74 pub struct DefaultDnsFuture {
75     inner: JoinHandle<Result<ResolvedAddrs, Error>>,
76 }
77 
78 impl Future for DefaultDnsFuture {
79     type Output = Result<Addrs, StdError>;
80 
pollnull81     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
82         Pin::new(&mut self.inner).poll(cx).map(|res| match res {
83             Ok(Ok(addrs)) => Ok(Box::new(addrs) as Addrs),
84             Ok(Err(err)) => Err(Box::new(err) as StdError),
85             Err(err) => Err(Box::new(Error::new(io::ErrorKind::Interrupted, err)) as StdError),
86         })
87     }
88 }
89 
90 /// Default dns resolver used by the `Client`。
91 #[derive(Default)]
92 pub struct DefaultDnsResolver {}
93 
94 impl Resolver for DefaultDnsResolver {
resolvenull95     fn resolve(&self, domain: &str) -> SocketFuture {
96         let domain: Box<str> = domain.into();
97         let blocking = crate::runtime::spawn_blocking(move || {
98             (*domain)
99                 .to_socket_addrs()
100                 .map(|iter| ResolvedAddrs { iter })
101         });
102         Box::pin(DefaultDnsFuture { inner: blocking })
103     }
104 }
105 
106 #[cfg(test)]
107 mod ut_dns_resolver {
108     use crate::async_impl::{DefaultDnsResolver, Resolver};
109 
110     /// UT test cases for `FrameDecoder::decode`.
111     ///
112     /// # Brief
113     ///
114     /// Test a simple complete DATA frame.
115     /// 1. Creates a `FrameDecoder`.
116     /// 2. Calls its `FrameDecoder::decode` method.
117     /// 3. Checks the results.
118     #[test]
119     #[cfg(feature = "ylong_base")]
ut_resolver_std_dns_resolver_resolvenull120     fn ut_resolver_std_dns_resolver_resolve() {
121         ylong_runtime::block_on(async move {
122             let resolver = DefaultDnsResolver {};
123             let sockets = resolver
124                 .resolve("www.baidu.com:80")
125                 .await
126                 .expect("dns resolver resolve domain occurs err");
127             let mut size = 0;
128             for _socket in sockets.into_iter() {
129                 size += 1;
130             }
131             assert!(size > 0);
132         });
133     }
134 
135     /// UT test cases for `FrameDecoder::decode`.
136     ///
137     /// # Brief
138     ///
139     /// Test a simple complete DATA frame.
140     /// 1. Creates a `FrameDecoder`.
141     /// 2. Calls its `FrameDecoder::decode` method.
142     /// 3. Checks the results.
143     #[test]
144     #[cfg(feature = "tokio_base")]
ut_resolver_std_dns_resolver_resolvenull145     fn ut_resolver_std_dns_resolver_resolve() {
146         let runtime = tokio::runtime::Builder::new_multi_thread()
147             .worker_threads(1)
148             .enable_all()
149             .build()
150             .expect("Build runtime failed.");
151         runtime.block_on(async move {
152             let resolver = DefaultDnsResolver {};
153             let sockets = resolver
154                 .resolve("www.baidu.com:80")
155                 .await
156                 .expect("dns resolver resolve domain occurs err");
157             let mut size = 0;
158             for _socket in sockets.into_iter() {
159                 size += 1;
160             }
161             assert!(size > 0);
162         });
163     }
164 }
165