iasc 0.1.0

an Ip-address And Subnet-mask Calculator
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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206

//! # Ip address And Subnet mask Converter
//! This CLI tool can convert some Network's address to another address.
//!
//! ## Usage
//! ```shell
//! iasc --conversion-type prefix-to-subnet --prefix-length 24
//! # Output
//! 255.255.255.0
//! ```
//! ```shell
//! iasc --conversion-type subnet-to-prefix --subnet-mask "255.255.255.0"
//! # Output
//! 24
//! ```

use clap::Parser;
use clap::ValueEnum;
use std::net::Ipv4Addr;

pub type SubnetMask = Ipv4Addr;

#[derive(Debug, Parser)]
#[command(version, about, author)]
pub struct Args {
    /// Specify the IP address.
    #[arg(long)]
    pub ip_address: Option<String>,

    /// Specify the subnet mask.
    #[arg(long)]
    pub subnet_mask: Option<String>,

    /// Specify the prefix length.
    #[arg(long)]
    pub prefix_length: Option<usize>,

    /// Specify the conversion type.
    #[arg(short, long)]
    pub conversion_type: Option<ConversionType>,
}

/// This enum is used whether the user wants to convert subnet mask to prefix length or prefix length to subnet mask.
#[derive(Clone, Debug, ValueEnum)]
pub enum ConversionType {
    SubnetToPrefix,
    PrefixToSubnet,
}

impl std::str::FromStr for ConversionType {
    type Err = String;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "subnet-to-prefix" => Ok(ConversionType::SubnetToPrefix),
            "prefix-to-subnet" => Ok(ConversionType::PrefixToSubnet),
            _ => Err(String::from("Invalid conversion type")),
        }
    }
}

/// Calculate the prefix length from the given subnet mask.
pub fn subnet_to_prefix(subnet: SubnetMask) -> Result<PrefixLength, String> {
    let subnet_string: String = subnet.to_string();
    match &subnet_string[..] {
        "255.255.255.255" => Ok(PrefixLength::new(32)?),
        "255.255.255.254" => Ok(PrefixLength::new(31)?),
        "255.255.255.252" => Ok(PrefixLength::new(30)?),
        "255.255.255.248" => Ok(PrefixLength::new(29)?),
        "255.255.255.240" => Ok(PrefixLength::new(28)?),
        "255.255.255.224" => Ok(PrefixLength::new(27)?),
        "255.255.255.192" => Ok(PrefixLength::new(26)?),
        "255.255.255.128" => Ok(PrefixLength::new(25)?),
        "255.255.255.0" => Ok(PrefixLength::new(24)?),
        "255.255.254.0" => Ok(PrefixLength::new(23)?),
        "255.255.252.0" => Ok(PrefixLength::new(22)?),
        "255.255.248.0" => Ok(PrefixLength::new(21)?),
        "255.255.240.0" => Ok(PrefixLength::new(20)?),
        "255.255.224.0" => Ok(PrefixLength::new(19)?),
        "255.255.192.0" => Ok(PrefixLength::new(18)?),
        "255.255.128.0" => Ok(PrefixLength::new(17)?),
        "255.255.0.0" => Ok(PrefixLength::new(16)?),
        "255.254.0.0" => Ok(PrefixLength::new(15)?),
        "255.252.0.0" => Ok(PrefixLength::new(14)?),
        "255.248.0.0" => Ok(PrefixLength::new(13)?),
        "255.240.0.0" => Ok(PrefixLength::new(12)?),
        "255.224.0.0" => Ok(PrefixLength::new(11)?),
        "255.192.0.0" => Ok(PrefixLength::new(10)?),
        "255.128.0.0" => Ok(PrefixLength::new(9)?),
        "255.0.0.0" => Ok(PrefixLength::new(8)?),
        "254.0.0.0" => Ok(PrefixLength::new(7)?),
        "252.0.0.0" => Ok(PrefixLength::new(6)?),
        "248.0.0.0" => Ok(PrefixLength::new(5)?),
        "240.0.0.0" => Ok(PrefixLength::new(4)?),
        "224.0.0.0" => Ok(PrefixLength::new(3)?),
        "192.0.0.0" => Ok(PrefixLength::new(2)?),
        "128.0.0.0" => Ok(PrefixLength::new(1)?),
        _ => Err(String::from(
            "Cannot calcurate the SubnetMask... Perhaps, do you input invalid SubnetMask?",
        )),
    }
}

/// Calculate the subnet mask from the given prefix length.
pub fn prefix_to_subnet(prefix: PrefixLength) -> Result<SubnetMask, String> {
    let prefix_string: String = prefix.to_string();
    match &prefix_string[..] {
        "32" => Ok(SubnetMask::new(255, 255, 255, 255)),
        "31" => Ok(SubnetMask::new(255, 255, 255, 254)),
        "30" => Ok(SubnetMask::new(255, 255, 255, 252)),
        "29" => Ok(SubnetMask::new(255, 255, 255, 248)),
        "28" => Ok(SubnetMask::new(255, 255, 255, 240)),
        "27" => Ok(SubnetMask::new(255, 255, 255, 224)),
        "26" => Ok(SubnetMask::new(255, 255, 255, 192)),
        "25" => Ok(SubnetMask::new(255, 255, 255, 128)),
        "24" => Ok(SubnetMask::new(255, 255, 255, 0)),
        "23" => Ok(SubnetMask::new(255, 255, 254, 0)),
        "22" => Ok(SubnetMask::new(255, 255, 252, 0)),
        "21" => Ok(SubnetMask::new(255, 255, 248, 0)),
        "20" => Ok(SubnetMask::new(255, 255, 240, 0)),
        "19" => Ok(SubnetMask::new(255, 255, 224, 0)),
        "18" => Ok(SubnetMask::new(255, 255, 192, 0)),
        "17" => Ok(SubnetMask::new(255, 255, 128, 0)),
        "16" => Ok(SubnetMask::new(255, 255, 0, 0)),
        "15" => Ok(SubnetMask::new(255, 254, 0, 0)),
        "14" => Ok(SubnetMask::new(255, 252, 0, 0)),
        "13" => Ok(SubnetMask::new(255, 248, 0, 0)),
        "12" => Ok(SubnetMask::new(255, 240, 0, 0)),
        "11" => Ok(SubnetMask::new(255, 224, 0, 0)),
        "10" => Ok(SubnetMask::new(255, 192, 0, 0)),
        "9" => Ok(SubnetMask::new(255, 128, 0, 0)),
        "8" => Ok(SubnetMask::new(255, 0, 0, 0)),
        "7" => Ok(SubnetMask::new(254, 0, 0, 0)),
        "6" => Ok(SubnetMask::new(252, 0, 0, 0)),
        "5" => Ok(SubnetMask::new(248, 0, 0, 0)),
        "4" => Ok(SubnetMask::new(240, 0, 0, 0)),
        "3" => Ok(SubnetMask::new(224, 0, 0, 0)),
        "2" => Ok(SubnetMask::new(192, 0, 0, 0)),
        "1" => Ok(SubnetMask::new(128, 0, 0, 0)),
        _ => Err(String::from(
            "Cannot calcurate the PrefixLength... Perhaps, do you input invalid PrefixLength?",
        )),
    }
}

#[derive(Debug)]
pub struct PrefixLength {
    /// The length of the prefix.
    pub length: u8,
}

impl std::fmt::Display for PrefixLength {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.length)
    }
}

impl PrefixLength {
    pub fn new(length: usize) -> Result<Self, String> {
        match length {
            0 => Err(String::from("Prefix length must not be 0")),
            1..=32 => Ok(PrefixLength {
                length: length as u8,
            }),
            33.. => Err(String::from("Prefix length must not be greater than 32")),
        }
    }
}

#[cfg(test)]
mod test {
    use crate::{prefix_to_subnet, subnet_to_prefix, PrefixLength, SubnetMask};

    #[test]
    fn test_prefix_to_subnet() {
        let prefix: PrefixLength = PrefixLength::new(24).unwrap();

        assert_eq!(
            prefix_to_subnet(prefix).unwrap().to_string(),
            "255.255.255.0"
        );
    }

    #[test]
    #[should_panic(expected = "Prefix length must not be greater than 32")]
    fn test_invalid_prefix() {
        let _invalid_prefix: PrefixLength = PrefixLength::new(33).unwrap();
    }

    #[test]
    #[should_panic(expected = "Prefix length must not be 0")]
    fn test_zero_prefix() {
        let _zero_prefix: PrefixLength = PrefixLength::new(0).unwrap();
    }

    #[test]
    fn test_subnet_to_prefix() {
        const SUBNET: SubnetMask = SubnetMask::new(255, 255, 255, 0);
        const INVALID_SUBNET: SubnetMask = SubnetMask::new(255, 255, 255, 123);

        assert_eq!(subnet_to_prefix(SUBNET).unwrap().to_string(), "24");
        assert_eq!(
            subnet_to_prefix(INVALID_SUBNET).unwrap_err(),
            "Cannot calcurate the SubnetMask... Perhaps, do you input invalid SubnetMask?"
        );
    }
}