dnsi 0.2.0

A tool for investigating the DNS.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

//! The lookup command of _dnsi._

use crate::error::Error;
use domain::base::name::UncertainName;
use domain::resolv::stub::StubResolver;
use std::net::IpAddr;
use std::str::FromStr;

//------------ Lookup --------------------------------------------------------

#[derive(Clone, Debug, clap::Args)]
pub struct Lookup {
    /// The host or address to look up.
    #[arg(value_name = "HOST_OR_ADDR")]
    names: Vec<ServerName>,
}

/// # Executing the command
///
impl Lookup {
    pub fn execute(self) -> Result<(), Error> {
        tokio::runtime::Builder::new_multi_thread()
            .enable_all()
            .build()
            .unwrap()
            .block_on(self.async_execute())
    }

    pub async fn async_execute(self) -> Result<(), Error> {
        let resolver = StubResolver::new();

        let mut res = Ok(());
        let mut names = self.names.iter();

        if let Some(name) = names.next() {
            res = res.and(self.execute_one_name(&resolver, name).await);
        }

        for name in names {
            println!();
            res = res.and(self.execute_one_name(&resolver, name).await);
        }

        res.map_err(|_| "not all lookups have succeeded".into())
    }

    async fn execute_one_name(
        &self,
        resolver: &StubResolver,
        name: &ServerName,
    ) -> Result<(), ()> {
        let res = match name {
            ServerName::Name(host) => forward(resolver, host).await,
            ServerName::Addr(addr) => reverse(resolver, *addr).await,
        };

        if let Err(err) = res {
            eprintln!("{err}");
            return Err(());
        }

        Ok(())
    }
}

async fn forward(
    resolver: &StubResolver,
    name: &UncertainName<Vec<u8>>,
) -> Result<(), Error> {
    let answer = match name {
        UncertainName::Absolute(ref name) => {
            resolver.lookup_host(name).await?
        }
        UncertainName::Relative(ref name) => {
            resolver.search_host(name).await?
        }
    };

    print!("{name}");

    let canon = answer.canonical_name();
    if canon != answer.qname() {
        print!(" (alias for {canon})");
    }

    println!();

    let addrs: Vec<_> = answer.iter().collect();
    if addrs.is_empty() {
        println!("  <no addresses found>");
    } else {
        for addr in addrs {
            println!("  {addr}");
        }
    }

    Ok(())
}

async fn reverse(resolver: &StubResolver, addr: IpAddr) -> Result<(), Error> {
    let answer = resolver.lookup_addr(addr).await?;
    println!("{addr}");

    let hosts: Vec<_> = answer.iter().collect();
    if hosts.is_empty() {
        println!("  <no hosts found>");
    } else {
        for name in hosts {
            println!("  {name}");
        }
    }

    Ok(())
}

//------------ ServerName ---------------------------------------------------

#[derive(Clone, Debug)]
enum ServerName {
    Name(UncertainName<Vec<u8>>),
    Addr(IpAddr),
}

impl FromStr for ServerName {
    type Err = &'static str;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if let Ok(addr) = IpAddr::from_str(s) {
            Ok(ServerName::Addr(addr))
        } else {
            UncertainName::from_str(s)
                .map(Self::Name)
                .map_err(|_| "illegal host name or address")
        }
    }
}