# dns-lookup
[](https://crates.io/crates/dns-lookup)
A small wrapper for libc to perform simple DNS lookups.
You can use the `lookup_host` function to get a list of IP Addresses for a
given hostname, and the `lookup_name` function to get the reverse dns entry for
the given IP Address.
PS: If you only need a single result, consider
[ToSocketAddrs](https://doc.rust-lang.org/std/net/trait.ToSocketAddrs.html) in libstd.
The library also includes a safe wrapper for `getaddrinfo` and `getnameinfo`.
[Documentation](https://docs.rs/dns-lookup/)
## Usage
### Simple API
```rust
use dns_lookup::{lookup_host, lookup_addr};
{
let hostname = "localhost";
let ips: Vec<std::net::IpAddr> = lookup_host(hostname).unwrap();
assert!(ips.contains(&"127.0.0.1".parse().unwrap()));
}
{
let ip: std::net::IpAddr = "127.0.0.1".parse().unwrap();
let host = lookup_addr(&ip).unwrap();
// The string "localhost" on unix, and the hostname on Windows.
}
```
### libc API
```rust
{
extern crate dns_lookup;
use dns_lookup::{getaddrinfo, AddrInfoHints, SockType};
fn main() {
let hostname = "localhost";
let service = "ssh";
let hints = AddrInfoHints {
socktype: SockType::Stream.into(),
.. AddrInfoHints::default()
};
let sockets =
getaddrinfo(Some(hostname), Some(service), Some(hints))
.unwrap().collect::<std::io::Result<Vec<_>>>().unwrap();
for socket in sockets {
// Try connecting to socket
println!("{:?}", socket);
}
}
}
{
use dns_lookup::getnameinfo;
use std::net::{IpAddr, SocketAddr};
let ip: IpAddr = "127.0.0.1".parse().unwrap();
let port = 22;
let socket: SocketAddr = (ip, port).into();
let (name, service) = match getnameinfo(&socket, 0) {
Ok((n, s)) => (n, s),
Err(e) => panic!("Failed to lookup socket {:?}", e),
};
println!("{:?} {:?}", name, service);
let _ = (name, service);
}
{
use dns_lookup::gethostname;
let hostname = gethostname().unwrap();
}
```