simple_dns/dns/rdata/
mx.rs

1use crate::{
2    bytes_buffer::BytesBuffer,
3    dns::{Name, WireFormat},
4    lib::{Seek, Write},
5};
6
7use super::RR;
8
9/// MX is used to acquire mail exchange information
10#[derive(Debug, PartialEq, Eq, Hash, Clone)]
11pub struct MX<'a> {
12    /// A 16 bit integer which specifies the preference given to this RR among others at the same owner.  
13    /// Lower values are preferred.
14    pub preference: u16,
15
16    /// A [Name](`Name`) which specifies a host willing to act as a mail exchange for the owner name.
17    pub exchange: Name<'a>,
18}
19
20impl RR for MX<'_> {
21    const TYPE_CODE: u16 = 15;
22}
23
24impl MX<'_> {
25    /// Transforms the inner data into its owned type
26    pub fn into_owned<'b>(self) -> MX<'b> {
27        MX {
28            preference: self.preference,
29            exchange: self.exchange.into_owned(),
30        }
31    }
32}
33
34impl<'a> WireFormat<'a> for MX<'a> {
35    const MINIMUM_LEN: usize = 2;
36
37    fn parse(data: &mut BytesBuffer<'a>) -> crate::Result<Self>
38    where
39        Self: Sized,
40    {
41        let preference = data.get_u16()?;
42        let exchange = Name::parse(data)?;
43
44        Ok(Self {
45            preference,
46            exchange,
47        })
48    }
49
50    fn write_to<T: Write>(&self, out: &mut T) -> crate::Result<()> {
51        out.write_all(&self.preference.to_be_bytes())?;
52        self.exchange.write_to(out)
53    }
54
55    fn write_compressed_to<T: Write + Seek>(
56        &'a self,
57        out: &mut T,
58        name_refs: &mut crate::lib::BTreeMap<&[crate::Label<'a>], u16>,
59    ) -> crate::Result<()> {
60        out.write_all(&self.preference.to_be_bytes())?;
61        self.exchange.write_compressed_to(out, name_refs)
62    }
63
64    fn len(&self) -> usize {
65        self.exchange.len() + Self::MINIMUM_LEN
66    }
67}
68
69#[cfg(test)]
70mod tests {
71    use super::*;
72    use crate::lib::{ToString, Vec};
73
74    #[test]
75    fn parse_and_write_mx() {
76        let mx = MX {
77            preference: 10,
78            exchange: Name::new("e.exchange.com").unwrap(),
79        };
80
81        let mut data = Vec::new();
82        assert!(mx.write_to(&mut data).is_ok());
83
84        let mx = MX::parse(&mut data[..].into());
85        assert!(mx.is_ok());
86        let mx = mx.unwrap();
87
88        assert_eq!(data.len(), mx.len());
89        assert_eq!(10, mx.preference);
90        assert_eq!("e.exchange.com", mx.exchange.to_string());
91    }
92
93    #[test]
94    #[cfg(feature = "std")]
95    fn parse_sample() -> Result<(), Box<dyn std::error::Error>> {
96        use crate::{rdata::RData, ResourceRecord};
97        let sample_file = std::fs::read("samples/zonefile/MX.sample")?;
98
99        let sample_rdata = match ResourceRecord::parse(&mut sample_file[..].into())?.rdata {
100            RData::MX(rdata) => rdata,
101            _ => unreachable!(),
102        };
103
104        assert_eq!(sample_rdata.preference, 10);
105        assert_eq!(sample_rdata.exchange, "VENERA.sample".try_into()?);
106        Ok(())
107    }
108}
simple_dns/dns/rdata/mx.rs

simple_dns/dns/rdata/
mx.rs
