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test(dns): pin zero through the wire format and the zone file #233

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Merged
Meldiron merged 1 commit into from
Sep 8, 2026
Merged

test(dns): pin zero through the wire format and the zone file #233

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94 changes: 94 additions & 0 deletions packages/dns/tests/unit/DNS/Message/RecordTest.php
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -150,6 +150,100 @@ public function testDecodeSrvRecordParsesFields(): void
$this->assertSame(\strlen($data), $offset);
}

public function testEncodeMxRecordWithZeroPriorityMatchesBytes(): void
{
// Zero is the highest priority a mail exchange can be given, and it is a value the sender
// chose rather than one it omitted. It has to reach the wire as two zero octets.
$record = new Record(
name: 'mail.example.com',
type: Record::TYPE_MX,
class: Record::CLASS_IN,
ttl: 3600,
rdata: 'mail.exchange.example.com',
priority: 0,
);

// Raw RR: mail.example.com. 3600 IN MX 0 mail.exchange.example.com.
$expected = "\x04mail\x07example\x03com\x00"
. "\x00\x0F"
. "\x00\x01"
. "\x00\x00\x0E\x10"
. "\x00\x1D"
. "\x00\x00"
. "\x04mail\x08exchange\x07example\x03com\x00";

$this->assertSame($expected, $record->encode());
}

public function testDecodeMxRecordWithZeroPriorityParsesFields(): void
{
// Raw RR: mail.example.com. 3600 IN MX 0 mail.exchange.example.com.
$data = "\x04mail\x07example\x03com\x00"
. "\x00\x0F"
. "\x00\x01"
. "\x00\x00\x0E\x10"
. "\x00\x1D"
. "\x00\x00"
. "\x04mail\x08exchange\x07example\x03com\x00";

$offset = 0;
$record = Record::decode($data, $offset);

// A zero read off the wire stays a zero, rather than becoming the null that means "this
// record type carries no priority".
$this->assertSame(0, $record->priority);
$this->assertSame('mail.exchange.example.com', $record->rdata);
$this->assertSame(\strlen($data), $offset);
}

public function testEncodeSrvRecordWithZeroNumericsMatchesBytes(): void
{
// RFC 2782 gives all three fields a meaning at zero: highest priority, no share of the
// weighted draw, and the port that marks the service unavailable on this target.
$record = new Record(
name: '_sip._tcp.example.com',
type: Record::TYPE_SRV,
class: Record::CLASS_IN,
ttl: 7200,
rdata: 'sip.example.com',
priority: 0,
weight: 0,
port: 0,
);

// Raw RR: _sip._tcp.example.com. 7200 IN SRV 0 0 0 sip.example.com.
$expected = "\x04_sip\x04_tcp\x07example\x03com\x00"
. "\x00\x21"
. "\x00\x01"
. "\x00\x00\x1C\x20"
. "\x00\x17"
. "\x00\x00\x00\x00\x00\x00"
. "\x03sip\x07example\x03com\x00";

$this->assertSame($expected, $record->encode());
}

public function testDecodeSrvRecordWithZeroNumericsParsesFields(): void
{
// Raw RR: _sip._tcp.example.com. 7200 IN SRV 0 0 0 sip.example.com.
$data = "\x04_sip\x04_tcp\x07example\x03com\x00"
. "\x00\x21"
. "\x00\x01"
. "\x00\x00\x1C\x20"
. "\x00\x17"
. "\x00\x00\x00\x00\x00\x00"
. "\x03sip\x07example\x03com\x00";

$offset = 0;
$record = Record::decode($data, $offset);

$this->assertSame(0, $record->priority);
$this->assertSame(0, $record->weight);
$this->assertSame(0, $record->port);
$this->assertSame('sip.example.com', $record->rdata);
$this->assertSame(\strlen($data), $offset);
}

public function testEncodeTxtRecordMatchesBytes(): void
{
$record = new Record(
Expand Down
47 changes: 47 additions & 0 deletions packages/dns/tests/unit/DNS/Zone/FileTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -411,6 +411,53 @@ public function testExportBasicZone(): void
$this->assertSame('mail.example.com', $roundTrip->records[2]->name);
}

public function testExportAndImportKeepZeroMxPriority(): void
{
// The zone file is the only thing a resolver reads. A priority of 0 written as an empty
// field does not just lose the priority: the line stops parsing, and an import failure
// takes every other record in the zone with it.
$zone = new Zone(
'example.com',
[
new Record('mail.example.com', Record::TYPE_MX, Record::CLASS_IN, 300, 'mail.example.com', priority: 0),
],
new Record('example.com', Record::TYPE_SOA, Record::CLASS_IN, 1800, 'ns1.example.com. admin.example.com. 2025011801 7200 3600 1209600 1800'),
);

$exported = File::export($zone, includeComments: false);
$this->assertStringContainsString("mail\t300\tIN\tMX\t0 mail\n", $exported);

$roundTrip = File::import($exported);
$record = $this->findRecord($roundTrip->records, Record::TYPE_MX);

$this->assertInstanceOf(Record::class, $record);
$this->assertSame(0, $record->priority);
$this->assertSame('mail.example.com', $record->rdata);
}

public function testExportAndImportKeepZeroSrvNumerics(): void
{
$zone = new Zone(
'example.com',
[
new Record('_sip._tcp.example.com', Record::TYPE_SRV, Record::CLASS_IN, 300, 'sip.example.com', priority: 0, weight: 0, port: 0),
],
new Record('example.com', Record::TYPE_SOA, Record::CLASS_IN, 1800, 'ns1.example.com. admin.example.com. 2025011801 7200 3600 1209600 1800'),
);

$exported = File::export($zone, includeComments: false);
$this->assertStringContainsString("_sip._tcp\t300\tIN\tSRV\t0 0 0 sip\n", $exported);

$roundTrip = File::import($exported);
$record = $this->findRecord($roundTrip->records, Record::TYPE_SRV);

$this->assertInstanceOf(Record::class, $record);
$this->assertSame(0, $record->priority);
$this->assertSame(0, $record->weight);
$this->assertSame(0, $record->port);
$this->assertSame('sip.example.com', $record->rdata);
}

public function testImportSupportsPtrRecords(): void
{
$soa = self::DEFAULT_SOA;
Expand Down
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