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Mercurial > core / rust/lib/net/src/engine/dns/resolver.rs

changeset 698: 96958d3eb5b0
parent: 3d78bed56188
author: Richard Westhaver <ellis@rwest.io>
date: Fri, 04 Oct 2024 22:04:59 -0400
permissions: -rw-r--r--
description: fixes 
     1 use crate::Result;
     2 
     3 use hickory_resolver::{
     4   config::{NameServerConfig, Protocol, ResolverConfig, ResolverOpts},
     5   error::ResolveErrorKind,
     6   TokioAsyncResolver,
     7 };
     8 use std::{
     9   future::Future,
    10   net::{IpAddr, Ipv4Addr, SocketAddr, SocketAddrV4},
    11 };
    12 
    13 pub trait Lookup: Send + 'static {
    14   fn lookup(
    15     &self,
    16     ip: IpAddr,
    17   ) -> impl Future<Output = Option<String>> + Send + '_;
    18 }
    19 
    20 #[repr(transparent)]
    21 pub struct Resolver(pub TokioAsyncResolver);
    22 unsafe impl Send for Resolver {}
    23 impl Resolver {
    24   pub async fn new(dns_server: &Option<Ipv4Addr>) -> Result<Self> {
    25     let resolver = match dns_server {
    26       Some(dns_server_address) => {
    27         let mut config = ResolverConfig::new();
    28         let options = ResolverOpts::default();
    29         let socket = SocketAddr::V4(SocketAddrV4::new(*dns_server_address, 53));
    30         let nameserver_config = NameServerConfig {
    31           socket_addr: socket,
    32           protocol: Protocol::Udp,
    33           tls_dns_name: None,
    34           trust_negative_responses: false,
    35           bind_addr: None,
    36         };
    37         config.add_name_server(nameserver_config);
    38         TokioAsyncResolver::tokio(config, options)
    39       }
    40       None => TokioAsyncResolver::tokio_from_system_conf().unwrap(),
    41     };
    42     Ok(Self(resolver))
    43   }
    44 }
    45 
    46 impl Lookup for Resolver {
    47   async fn lookup(&self, ip: IpAddr) -> Option<String> {
    48     let lookup_future = self.0.reverse_lookup(ip);
    49     match lookup_future.await {
    50       Ok(names) => {
    51         // Take the first result and convert it to a string
    52         names.into_iter().next().map(|x| x.to_string())
    53       }
    54       Err(e) => match e.kind() {
    55         // If the IP is not associated with a hostname, store the IP
    56         // so that we don't retry indefinitely
    57         ResolveErrorKind::NoRecordsFound { .. } => Some(ip.to_string()),
    58         _ => None,
    59       },
    60     }
    61   }
    62 }