dns_server/
dns_class.rs

1use crate::{read_u16_be, write_u16_be, DnsError};
2use fixed_buffer::FixedBuf;
3
4/// > `CLASS` fields appear in resource records.  The following `CLASS` mnemonics and values are
5/// > defined:
6/// >
7/// > - `IN` 1 the Internet
8/// > - `CS` 2 the CSNET class (Obsolete - used only for examples in some obsolete RFCs)
9/// > - `CH` 3 the CHAOS class
10/// > - `HS` 4 Hesiod [Dyer 87]
11/// >
12/// >
13/// > `QCLASS` fields appear in the question section of a query.  `QCLASS` values are a superset of
14/// > `CLASS` values; every `CLASS` is a valid `QCLASS`.  In addition to `CLASS` values, the following
15/// > `QCLASSes` are defined:
16/// >
17/// > - `*` 255 any class
18///
19/// <https://datatracker.ietf.org/doc/html/rfc1035#section-3.2.4>
20#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
21pub enum DnsClass {
22    Internet,
23    Any,
24    Unknown(u16),
25}
26impl DnsClass {
27    #[must_use]
28    pub fn new(value: u16) -> Self {
29        match value {
30            1 => DnsClass::Internet,
31            255 => DnsClass::Any,
32            other => DnsClass::Unknown(other),
33        }
34    }
35
36    #[must_use]
37    pub fn num(&self) -> u16 {
38        match self {
39            DnsClass::Internet => 1,
40            DnsClass::Any => 255,
41            DnsClass::Unknown(other) => *other,
42        }
43    }
44
45    /// # Errors
46    /// Returns an error when `buf` does not contain two bytes.
47    pub fn read<const N: usize>(buf: &mut FixedBuf<N>) -> Result<Self, DnsError> {
48        Ok(Self::new(read_u16_be(buf)?))
49    }
50
51    /// # Errors
52    /// Returns an error when `buf` is full.
53    pub fn write<const N: usize>(&self, out: &mut FixedBuf<N>) -> Result<(), DnsError> {
54        write_u16_be(out, self.num())
55    }
56}
dns_server/dns_class.rs

dns_server/
dns_class.rs
