c_ares/
ptr.rs

1use std::fmt;
2use std::os::raw::{c_int, c_uchar, c_void};
3use std::ptr;
4use std::slice;
5
6use itertools::Itertools;
7
8use crate::error::{Error, Result};
9use crate::hostent::{HasHostent, HostAliasResultsIter, HostentOwned};
10use crate::panic;
11
12/// The result of a successful PTR lookup.
13#[derive(Debug)]
14pub struct PTRResults {
15    hostent: HostentOwned,
16}
17
18impl PTRResults {
19    /// Obtain a `PTRResults` from the response to a PTR lookup.
20    pub fn parse_from(data: &[u8]) -> Result<PTRResults> {
21        let mut hostent: *mut c_types::hostent = ptr::null_mut();
22        let dummy_ip = [0, 0, 0, 0];
23        let parse_status = unsafe {
24            #[allow(clippy::useless_conversion)]
25            c_ares_sys::ares_parse_ptr_reply(
26                data.as_ptr(),
27                data.len() as c_int,
28                dummy_ip.as_ptr().cast(),
29                dummy_ip.len() as c_int,
30                c_types::AF_INET.into(),
31                &mut hostent,
32            )
33        };
34        if parse_status == c_ares_sys::ares_status_t::ARES_SUCCESS as i32 {
35            let result = PTRResults::new(hostent);
36            Ok(result)
37        } else {
38            Err(Error::from(parse_status))
39        }
40    }
41
42    fn new(hostent: *mut c_types::hostent) -> Self {
43        PTRResults {
44            hostent: HostentOwned::new(hostent),
45        }
46    }
47
48    /// Returns the hostname from this `PTRResults`.
49    pub fn hostname(&self) -> &str {
50        self.hostent.hostname()
51    }
52
53    /// Returns an iterator over the host aliases in this `PTRResults`.
54    pub fn aliases(&self) -> HostAliasResultsIter {
55        self.hostent.aliases()
56    }
57}
58
59impl fmt::Display for PTRResults {
60    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
61        write!(fmt, "Hostname: {}, ", self.hostname())?;
62        let aliases = self.aliases().format(", ");
63        write!(fmt, "Aliases: [{aliases}]")
64    }
65}
66
67pub(crate) unsafe extern "C" fn query_ptr_callback<F>(
68    arg: *mut c_void,
69    status: c_int,
70    _timeouts: c_int,
71    abuf: *mut c_uchar,
72    alen: c_int,
73) where
74    F: FnOnce(Result<PTRResults>) + Send + 'static,
75{
76    ares_callback!(arg.cast::<F>(), status, abuf, alen, PTRResults::parse_from);
77}
c_ares/ptr.rs

c_ares/
ptr.rs
