simple_dns/dns/rdata/
srv.rs

1use crate::{bytes_buffer::BytesBuffer, dns::WireFormat, lib::Write, Name};
2
3use super::RR;
4
5/// SRV records specifies the location of the server(s) for a specific protocol and domain.
6#[derive(Debug, PartialEq, Eq, Hash, Clone)]
7pub struct SRV<'a> {
8    /// The priority of this target host.  
9    /// A client MUST attempt to contact the target host with the lowest-numbered priority it can
10    /// reach; target hosts with the same priority SHOULD be tried in an order defined by the weight field.
11    pub priority: u16,
12    /// A server selection mechanism.  
13    /// The weight field specifies arelative weight for entries with the same priority.  
14    /// Larger weights SHOULD be given a proportionately higher probability of being selected.
15    pub weight: u16,
16    /// The port on this target host of this service
17    pub port: u16,
18    /// The domain name of the target host
19    pub target: Name<'a>,
20}
21
22impl RR for SRV<'_> {
23    const TYPE_CODE: u16 = 33;
24}
25
26impl SRV<'_> {
27    /// Transforms the inner data into its owned type
28    pub fn into_owned<'b>(self) -> SRV<'b> {
29        SRV {
30            priority: self.priority,
31            weight: self.weight,
32            port: self.port,
33            target: self.target.into_owned(),
34        }
35    }
36}
37
38impl<'a> WireFormat<'a> for SRV<'a> {
39    const MINIMUM_LEN: usize = 6;
40
41    fn parse(data: &mut BytesBuffer<'a>) -> crate::Result<Self>
42    where
43        Self: Sized,
44    {
45        let priority = data.get_u16()?;
46        let weight = data.get_u16()?;
47        let port = data.get_u16()?;
48        let target = Name::parse(data)?;
49
50        Ok(Self {
51            priority,
52            weight,
53            port,
54            target,
55        })
56    }
57
58    fn write_to<T: Write>(&self, out: &mut T) -> crate::Result<()> {
59        out.write_all(&self.priority.to_be_bytes())?;
60        out.write_all(&self.weight.to_be_bytes())?;
61        out.write_all(&self.port.to_be_bytes())?;
62
63        self.target.write_to(out)
64    }
65
66    fn len(&self) -> usize {
67        self.target.len() + Self::MINIMUM_LEN
68    }
69}
70
71#[cfg(test)]
72mod tests {
73    use super::*;
74    use crate::lib::Vec;
75
76    #[test]
77    fn parse_and_write_srv() {
78        let srv = SRV {
79            priority: 1,
80            weight: 2,
81            port: 3,
82            target: Name::new("_srv._tcp.example.com").unwrap(),
83        };
84
85        let mut bytes = Vec::new();
86        assert!(srv.write_to(&mut bytes).is_ok());
87
88        let srv = SRV::parse(&mut bytes[..].into());
89        assert!(srv.is_ok());
90        let srv = srv.unwrap();
91
92        assert_eq!(1, srv.priority);
93        assert_eq!(2, srv.weight);
94        assert_eq!(3, srv.port);
95        assert_eq!(bytes.len(), srv.len());
96    }
97
98    #[test]
99    fn srv_should_not_be_compressed() {
100        use crate::lib::Cursor;
101
102        let srv = SRV {
103            priority: 1,
104            weight: 2,
105            port: 3,
106            target: Name::new("_srv._tcp.example.com").unwrap(),
107        };
108
109        let mut plain = Vec::new();
110        let mut compressed = Cursor::new(Vec::new());
111        let mut names = Default::default();
112
113        assert!(srv.write_to(&mut plain).is_ok());
114        assert!(srv.write_compressed_to(&mut compressed, &mut names).is_ok());
115
116        assert_eq!(plain, compressed.into_inner());
117    }
118
119    #[test]
120    #[cfg(feature = "std")]
121    fn parse_sample() -> Result<(), Box<dyn std::error::Error>> {
122        use crate::{rdata::RData, ResourceRecord};
123        let sample_file = std::fs::read("samples/zonefile/SRV.sample")?;
124
125        let sample_rdata = match ResourceRecord::parse(&mut sample_file[..].into())?.rdata {
126            RData::SRV(rdata) => rdata,
127            _ => unreachable!(),
128        };
129
130        assert_eq!(sample_rdata.priority, 65535);
131        assert_eq!(sample_rdata.weight, 65535);
132        assert_eq!(sample_rdata.port, 65535);
133        assert_eq!(sample_rdata.target, "old-slow-box.sample".try_into()?);
134
135        Ok(())
136    }
137}
simple_dns/dns/rdata/srv.rs

simple_dns/dns/rdata/
srv.rs
