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
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
// Copyright 2015-2023 Benjamin Fry <benjaminfry@me.com>
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

//! start of authority record defining ownership and defaults for the zone

use std::fmt;

#[cfg(feature = "serde-config")]
use serde::{Deserialize, Serialize};

use crate::{
    error::ProtoResult,
    rr::{domain::Name, RData, RecordData, RecordType},
    serialize::binary::{BinDecodable, BinDecoder, BinEncodable, BinEncoder},
};

/// [RFC 1035, DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION, November 1987](https://tools.ietf.org/html/rfc1035)
///
/// ```text
/// 3.3.13. SOA RDATA format
///
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     /                     MNAME                     /
///     /                                               /
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     /                     RNAME                     /
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     |                    SERIAL                     |
///     |                                               |
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     |                    REFRESH                    |
///     |                                               |
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     |                     RETRY                     |
///     |                                               |
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     |                    EXPIRE                     |
///     |                                               |
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///     |                    MINIMUM                    |
///     |                                               |
///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
///
/// where:
///
/// SOA records cause no additional section processing.
///
/// All times are in units of seconds.
///
/// Most of these fields are pertinent only for name server maintenance
/// operations.  However, MINIMUM is used in all query operations that
/// retrieve RRs from a zone.  Whenever a RR is sent in a response to a
/// query, the TTL field is set to the maximum of the TTL field from the RR
/// and the MINIMUM field in the appropriate SOA.  Thus MINIMUM is a lower
/// bound on the TTL field for all RRs in a zone.  Note that this use of
/// MINIMUM should occur when the RRs are copied into the response and not
/// when the zone is loaded from a Zone File or via a zone transfer.  The
/// reason for this provision is to allow future dynamic update facilities to
/// change the SOA RR with known semantics.
/// ```
#[cfg_attr(feature = "serde-config", derive(Deserialize, Serialize))]
#[derive(Debug, PartialEq, Eq, Hash, Clone)]
pub struct SOA {
    mname: Name,
    rname: Name,
    serial: u32,
    refresh: i32,
    retry: i32,
    expire: i32,
    minimum: u32,
}

impl SOA {
    /// Creates a new SOA record data.
    ///
    /// # Arguments
    ///
    /// * `mname` - the name of the primary or authority for this zone.
    /// * `rname` - the name of the responsible party for this zone, e.g. an email address.
    /// * `serial` - the serial number of the zone, used for caching purposes.
    /// * `refresh` - the amount of time to wait before a zone is resynched.
    /// * `retry` - the minimum period to wait if there is a failure during refresh.
    /// * `expire` - the time until this primary is no longer authoritative for the zone.
    /// * `minimum` - no zone records should have time-to-live values less than this minimum.
    ///
    /// # Return value
    ///
    /// The newly created SOA record data.
    pub fn new(
        mname: Name,
        rname: Name,
        serial: u32,
        refresh: i32,
        retry: i32,
        expire: i32,
        minimum: u32,
    ) -> Self {
        Self {
            mname,
            rname,
            serial,
            refresh,
            retry,
            expire,
            minimum,
        }
    }

    /// Increments the serial number by one
    pub fn increment_serial(&mut self) {
        self.serial += 1; // TODO: what to do on overflow?
    }

    /// ```text
    /// MNAME           The <domain-name> of the name server that was the
    ///                 original or primary source of data for this zone.
    /// ```
    ///
    /// # Return value
    ///
    /// The `domain-name` of the name server that was the original or primary source of data for
    /// this zone, i.e. the Primary Name Server.
    pub fn mname(&self) -> &Name {
        &self.mname
    }

    /// ```text
    /// RNAME           A <domain-name> which specifies the mailbox of the
    ///                 person responsible for this zone.
    /// ```
    ///
    /// # Return value
    ///
    /// A `domain-name` which specifies the mailbox of the person responsible for this zone, i.e.
    /// the responsible name.
    pub fn rname(&self) -> &Name {
        &self.rname
    }

    /// ```text
    /// SERIAL          The unsigned 32 bit version number of the original copy
    ///                 of the zone.  Zone transfers preserve this value.  This
    ///                 value wraps and should be compared using sequence space
    ///                 arithmetic.
    /// ```
    ///
    /// # Return value
    ///
    /// The unsigned 32 bit version number of the original copy of the zone. Zone transfers
    /// preserve this value. This value wraps and should be compared using sequence space arithmetic.
    pub fn serial(&self) -> u32 {
        self.serial
    }

    /// ```text
    /// REFRESH         A 32 bit time interval before the zone should be
    ///                 refreshed.
    /// ```
    ///
    /// # Return value
    ///
    /// A 32 bit time interval before the zone should be refreshed, in seconds.
    pub fn refresh(&self) -> i32 {
        self.refresh
    }

    /// ```text
    /// RETRY           A 32 bit time interval that should elapse before a
    ///                 failed refresh should be retried.
    /// ```
    ///
    /// # Return value
    ///
    /// A 32 bit time interval that should elapse before a failed refresh should be retried,
    /// in seconds.
    pub fn retry(&self) -> i32 {
        self.retry
    }

    /// ```text
    /// EXPIRE          A 32 bit time value that specifies the upper limit on
    ///                 the time interval that can elapse before the zone is no
    ///                 longer authoritative.
    /// ```
    ///
    /// # Return value
    ///
    /// A 32 bit time value that specifies the upper limit on the time interval that can elapse
    /// before the zone is no longer authoritative, in seconds
    pub fn expire(&self) -> i32 {
        self.expire
    }

    /// ```text
    /// MINIMUM         The unsigned 32 bit minimum TTL field that should be
    ///                 exported with any RR from this zone.
    /// ```
    ///
    /// # Return value
    ///
    /// The unsigned 32 bit minimum TTL field that should be exported with any RR from this zone.
    pub fn minimum(&self) -> u32 {
        self.minimum
    }
}

impl BinEncodable for SOA {
    /// [RFC 4034](https://tools.ietf.org/html/rfc4034#section-6), DNSSEC Resource Records, March 2005
    ///
    /// This is accurate for all currently known name records.
    ///
    /// ```text
    /// 6.2.  Canonical RR Form
    ///
    ///    For the purposes of DNS security, the canonical form of an RR is the
    ///    wire format of the RR where:
    ///
    ///    ...
    ///
    ///    3.  if the type of the RR is NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
    ///        HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX,
    ///        SRV, DNAME, A6, RRSIG, or (rfc6840 removes NSEC), all uppercase
    ///        US-ASCII letters in the DNS names contained within the RDATA are replaced
    ///        by the corresponding lowercase US-ASCII letters;
    /// ```
    fn emit(&self, encoder: &mut BinEncoder<'_>) -> ProtoResult<()> {
        let is_canonical_names = encoder.is_canonical_names();

        // to_lowercase for rfc4034 and rfc6840
        self.mname
            .emit_with_lowercase(encoder, is_canonical_names)?;
        self.rname
            .emit_with_lowercase(encoder, is_canonical_names)?;
        encoder.emit_u32(self.serial)?;
        encoder.emit_i32(self.refresh)?;
        encoder.emit_i32(self.retry)?;
        encoder.emit_i32(self.expire)?;
        encoder.emit_u32(self.minimum)?;
        Ok(())
    }
}

impl<'r> BinDecodable<'r> for SOA {
    fn read(decoder: &mut BinDecoder<'r>) -> ProtoResult<Self> {
        Ok(Self {
            mname: Name::read(decoder)?,
            rname: Name::read(decoder)?,
            serial: decoder.read_u32()?.unverified(/*any u32 is valid*/),
            refresh: decoder.read_i32()?.unverified(/*any i32 is valid*/),
            retry: decoder.read_i32()?.unverified(/*any i32 is valid*/),
            expire: decoder.read_i32()?.unverified(/*any i32 is valid*/),
            minimum: decoder.read_u32()?.unverified(/*any u32 is valid*/),
        })
    }
}

impl RecordData for SOA {
    fn try_from_rdata(data: RData) -> Result<Self, RData> {
        match data {
            RData::SOA(soa) => Ok(soa),
            _ => Err(data),
        }
    }

    fn try_borrow(data: &RData) -> Option<&Self> {
        match data {
            RData::SOA(soa) => Some(soa),
            _ => None,
        }
    }

    fn record_type(&self) -> RecordType {
        RecordType::SOA
    }

    fn into_rdata(self) -> RData {
        RData::SOA(self)
    }
}

/// [RFC 1033](https://tools.ietf.org/html/rfc1033), DOMAIN OPERATIONS GUIDE, November 1987
///
/// ```text
/// SOA  (Start Of Authority)
///
/// <name>  [<ttl>]  [<class>]  SOA  <origin>  <person>  (
///    <serial>
///    <refresh>
///    <retry>
///    <expire>
///    <minimum> )
///
/// The Start Of Authority record designates the start of a zone.  The
/// zone ends at the next SOA record.
///
/// <name> is the name of the zone.
///
/// <origin> is the name of the host on which the master zone file
/// resides.
///
/// <person> is a mailbox for the person responsible for the zone.  It is
/// formatted like a mailing address but the at-sign that normally
/// separates the user from the host name is replaced with a dot.
///
/// <serial> is the version number of the zone file.  It should be
/// incremented anytime a change is made to data in the zone.
///
/// <refresh> is how long, in seconds, a secondary name server is to
/// check with the primary name server to see if an update is needed.  A
/// good value here would be one hour (3600).
///
/// <retry> is how long, in seconds, a secondary name server is to retry
/// after a failure to check for a refresh.  A good value here would be
/// 10 minutes (600).
///
/// <expire> is the upper limit, in seconds, that a secondary name server
/// is to use the data before it expires for lack of getting a refresh.
/// You want this to be rather large, and a nice value is 3600000, about
/// 42 days.
///
/// <minimum> is the minimum number of seconds to be used for TTL values
/// in RRs.  A minimum of at least a day is a good value here (86400).
///
/// There should only be one SOA record per zone.  A sample SOA record
/// would look something like:
///
/// @   IN   SOA   SRI-NIC.ARPA.   HOSTMASTER.SRI-NIC.ARPA. (
///     45         ;serial
///     3600       ;refresh
///     600        ;retry
///     3600000    ;expire
///     86400 )    ;minimum
/// ```
impl fmt::Display for SOA {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        write!(
            f,
            "{mname} {rname} {serial} {refresh} {retry} {expire} {min}",
            mname = self.mname,
            rname = self.rname,
            serial = self.serial,
            refresh = self.refresh,
            retry = self.retry,
            expire = self.expire,
            min = self.minimum
        )
    }
}

#[cfg(test)]
mod tests {
    #![allow(clippy::dbg_macro, clippy::print_stdout)]

    use crate::{rr::RecordDataDecodable, serialize::binary::Restrict};

    use super::*;

    #[test]
    fn test() {
        use std::str::FromStr;

        let rdata = SOA::new(
            Name::from_str("m.example.com").unwrap(),
            Name::from_str("r.example.com").unwrap(),
            1,
            2,
            3,
            4,
            5,
        );

        let mut bytes = Vec::new();
        let mut encoder: BinEncoder<'_> = BinEncoder::new(&mut bytes);
        assert!(rdata.emit(&mut encoder).is_ok());
        let bytes = encoder.into_bytes();
        let len = bytes.len() as u16;

        println!("bytes: {bytes:?}");

        let mut decoder: BinDecoder<'_> = BinDecoder::new(bytes);
        let read_rdata = SOA::read_data(&mut decoder, Restrict::new(len)).expect("Decoding error");
        assert_eq!(rdata, read_rdata);
    }
}