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
|
//! Resolve a Minecraft server address into an IP address and port.
use std::{
net::{IpAddr, SocketAddr},
sync::LazyLock,
};
pub use hickory_resolver::net::NetError as ResolveError;
use hickory_resolver::{
Resolver, TokioResolver,
config::{GOOGLE, ResolverConfig},
net::runtime::TokioRuntimeProvider,
proto::rr::{Name, RData},
};
use tracing::warn;
use crate::address::ServerAddr;
#[doc(hidden)]
#[deprecated(note = "Renamed to ResolveError")]
pub type ResolverError = ResolveError;
static RESOLVER: LazyLock<TokioResolver> = LazyLock::new(|| {
Resolver::builder_tokio()
.unwrap_or_else(|_| {
warn!("System DNS resolver unavailable; falling back to Google DNS.");
Resolver::builder_with_config(
ResolverConfig::udp_and_tcp(&GOOGLE),
TokioRuntimeProvider::new(),
)
})
.build()
.unwrap()
});
/// Resolve a Minecraft server address into an IP address and port.
///
/// If it's already an IP address, it's returned as-is.
pub async fn resolve_address(mut address: &ServerAddr) -> Result<SocketAddr, ResolveError> {
let redirect = resolve_srv_redirect(address).await;
if let Ok(redirect_target) = &redirect {
address = redirect_target;
}
resolve_ip_without_redirects(address).await
}
async fn resolve_ip_without_redirects(address: &ServerAddr) -> Result<SocketAddr, ResolveError> {
if let Ok(ip) = address.host.parse::<IpAddr>() {
// no need to do a lookup
return Ok(SocketAddr::new(ip, address.port));
}
let name = Name::from_ascii(&address.host)?;
let lookup_ip = RESOLVER.lookup_ip(name).await?;
let ip = lookup_ip
.iter()
.next()
.ok_or(ResolveError::from("No A/AAAA record found"))?;
Ok(SocketAddr::new(ip, address.port))
}
async fn resolve_srv_redirect(address: &ServerAddr) -> Result<ServerAddr, ResolveError> {
if address.port != 25565 {
return Err(ResolveError::from("Port must be 25565 to do a SRV lookup"));
}
let query = format!("_minecraft._tcp.{}", address.host);
let res = RESOLVER.srv_lookup(query).await?;
let srv = res
.answers()
.first()
.ok_or(ResolveError::from("No SRV record found"))?;
let RData::SRV(srv) = &srv.data else {
return Err(ResolveError::from(
"Record returned from SRV lookup wasn't SRV",
));
};
Ok(ServerAddr {
host: srv.target.to_ascii(),
port: srv.port,
})
}
|
