| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| import 'dart:convert'; |
| import 'dart:io'; |
| import 'dart:typed_data'; |
| |
| import 'package:meta/meta.dart'; |
| import 'constants.dart'; |
| import 'packet.dart'; |
| |
| /// Enumeration of support resource record types. |
| abstract class ResourceRecordType { |
| // This class is intended to be used as a namespace, and should not be |
| // extended directly. |
| ResourceRecordType._(); |
| |
| /// An IPv4 Address record, also known as an "A" record. It has a value of 1. |
| static const int addressIPv4 = 1; |
| |
| /// An IPv6 Address record, also known as an "AAAA" record. It has a vaule of |
| /// 28. |
| static const int addressIPv6 = 28; |
| |
| /// An IP Address reverse map record, also known as a "PTR" recored. It has a |
| /// value of 12. |
| static const int serverPointer = 12; |
| |
| /// An available service record, also known as an "SRV" record. It has a |
| /// value of 33. |
| static const int service = 33; |
| |
| /// A text record, also known as a "TXT" record. It has a value of 16. |
| static const int text = 16; |
| |
| // TODO(dnfield): Support ANY in some meaningful way. Might be server only. |
| // /// A query for all records of all types known to the name server. |
| // static const int any = 255; |
| |
| /// Checks that a given int is a valid ResourceRecordType. |
| /// |
| /// This method is intended to be called only from an `assert()`. |
| static bool debugAssertValid(int resourceRecordType) { |
| return resourceRecordType == addressIPv4 || |
| resourceRecordType == addressIPv6 || |
| resourceRecordType == serverPointer || |
| resourceRecordType == service || |
| resourceRecordType == text; |
| } |
| |
| /// Prints a debug-friendly version of the resource record type value. |
| static String toDebugString(int resourceRecordType) { |
| switch (resourceRecordType) { |
| case addressIPv4: |
| return 'A (IPv4 Address)'; |
| case addressIPv6: |
| return 'AAAA (IPv6 Address)'; |
| case serverPointer: |
| return 'PTR (Domain Name Pointer)'; |
| case service: |
| return 'SRV (Service record)'; |
| case text: |
| return 'TXT (Text)'; |
| } |
| return 'Unknown ($resourceRecordType)'; |
| } |
| } |
| |
| /// Represents a DNS query. |
| @immutable |
| class ResourceRecordQuery { |
| /// Creates a new ResourceRecordQuery. |
| /// |
| /// Most callers should prefer one of the named constructors. |
| ResourceRecordQuery( |
| this.resourceRecordType, |
| this.fullyQualifiedName, |
| this.questionType, |
| ) : assert(ResourceRecordType.debugAssertValid(resourceRecordType)); |
| |
| /// An A (IPv4) query. |
| ResourceRecordQuery.addressIPv4( |
| String name, { |
| bool isMulticast = true, |
| }) : this( |
| ResourceRecordType.addressIPv4, |
| name, |
| isMulticast ? QuestionType.multicast : QuestionType.unicast, |
| ); |
| |
| /// An AAAA (IPv6) query. |
| ResourceRecordQuery.addressIPv6( |
| String name, { |
| bool isMulticast = true, |
| }) : this( |
| ResourceRecordType.addressIPv6, |
| name, |
| isMulticast ? QuestionType.multicast : QuestionType.unicast, |
| ); |
| |
| /// A PTR (Server pointer) query. |
| ResourceRecordQuery.serverPointer( |
| String name, { |
| bool isMulticast = true, |
| }) : this( |
| ResourceRecordType.serverPointer, |
| name, |
| isMulticast ? QuestionType.multicast : QuestionType.unicast, |
| ); |
| |
| /// An SRV (Service) query. |
| ResourceRecordQuery.service( |
| String name, { |
| bool isMulticast = true, |
| }) : this( |
| ResourceRecordType.service, |
| name, |
| isMulticast ? QuestionType.multicast : QuestionType.unicast, |
| ); |
| |
| /// A TXT (Text record) query. |
| ResourceRecordQuery.text( |
| String name, { |
| bool isMulticast = true, |
| }) : this( |
| ResourceRecordType.text, |
| name, |
| isMulticast ? QuestionType.multicast : QuestionType.unicast, |
| ); |
| |
| /// Tye type of resource record - one of [ResourceRecordType]'s values. |
| final int resourceRecordType; |
| |
| /// The Fully Qualified Domain Name associated with the request. |
| final String fullyQualifiedName; |
| |
| /// The [QuestionType], i.e. multicast or unicast. |
| final int questionType; |
| |
| /// Convenience accessor to determine whether the question type is multicast. |
| bool get isMulticast => questionType == QuestionType.multicast; |
| |
| /// Convenience accessor to determine whether the question type is unicast. |
| bool get isUnicast => questionType == QuestionType.unicast; |
| |
| /// Encodes this query to the raw wire format. |
| List<int> encode() { |
| return encodeMDnsQuery( |
| fullyQualifiedName, |
| type: resourceRecordType, |
| multicast: isMulticast, |
| ); |
| } |
| |
| @override |
| int get hashCode => |
| Object.hash(resourceRecordType, fullyQualifiedName, questionType); |
| |
| @override |
| bool operator ==(Object other) { |
| return other is ResourceRecordQuery && |
| other.resourceRecordType == resourceRecordType && |
| other.fullyQualifiedName == fullyQualifiedName && |
| other.questionType == questionType; |
| } |
| |
| @override |
| String toString() => |
| 'ResourceRecordQuery{$fullyQualifiedName, type: ${ResourceRecordType.toDebugString(resourceRecordType)}, isMulticast: $isMulticast}'; |
| } |
| |
| /// Base implementation of DNS resource records (RRs). |
| @immutable |
| abstract class ResourceRecord { |
| /// Creates a new ResourceRecord. |
| const ResourceRecord(this.resourceRecordType, this.name, this.validUntil); |
| |
| /// The FQDN for this record. |
| final String name; |
| |
| /// The epoch time at which point this record is valid for in the cache. |
| final int validUntil; |
| |
| /// The raw resource record value. See [ResourceRecordType] for supported values. |
| final int resourceRecordType; |
| |
| String get _additionalInfo; |
| |
| @override |
| String toString() => |
| '$runtimeType{$name, validUntil: ${DateTime.fromMillisecondsSinceEpoch(validUntil)}, $_additionalInfo}'; |
| |
| @override |
| int get hashCode => Object.hash(name, validUntil, resourceRecordType); |
| |
| @override |
| bool operator ==(Object other) { |
| return other is ResourceRecord && |
| other.name == name && |
| other.validUntil == validUntil && |
| other.resourceRecordType == resourceRecordType; |
| } |
| |
| /// Low level method for encoding this record into an mDNS packet. |
| /// |
| /// Subclasses should provide the packet format of their encapsulated data |
| /// into a `Uint8List`, which could then be used to write a pakcet to send |
| /// as a response for this record type. |
| Uint8List encodeResponseRecord(); |
| } |
| |
| /// A Service Pointer for reverse mapping an IP address (DNS "PTR"). |
| class PtrResourceRecord extends ResourceRecord { |
| /// Creates a new PtrResourceRecord. |
| const PtrResourceRecord( |
| String name, |
| int validUntil, { |
| required this.domainName, |
| }) : super(ResourceRecordType.serverPointer, name, validUntil); |
| |
| /// The FQDN for this record. |
| final String domainName; |
| |
| @override |
| String get _additionalInfo => 'domainName: $domainName'; |
| |
| @override |
| int get hashCode => Object.hash(domainName.hashCode, super.hashCode); |
| |
| @override |
| bool operator ==(Object other) { |
| return super == other && |
| other is PtrResourceRecord && |
| other.domainName == domainName; |
| } |
| |
| @override |
| Uint8List encodeResponseRecord() { |
| return Uint8List.fromList(utf8.encode(domainName)); |
| } |
| } |
| |
| /// An IP Address record for IPv4 (DNS "A") or IPv6 (DNS "AAAA") records. |
| class IPAddressResourceRecord extends ResourceRecord { |
| /// Creates a new IPAddressResourceRecord. |
| IPAddressResourceRecord( |
| String name, |
| int validUntil, { |
| required this.address, |
| }) : super( |
| address.type == InternetAddressType.IPv4 |
| ? ResourceRecordType.addressIPv4 |
| : ResourceRecordType.addressIPv6, |
| name, |
| validUntil); |
| |
| /// The [InternetAddress] for this record. |
| final InternetAddress address; |
| |
| @override |
| String get _additionalInfo => 'address: $address'; |
| |
| @override |
| int get hashCode => Object.hash(address.hashCode, super.hashCode); |
| |
| @override |
| bool operator ==(Object other) { |
| return super == other && |
| other is IPAddressResourceRecord && |
| other.address == address; |
| } |
| |
| @override |
| Uint8List encodeResponseRecord() { |
| return Uint8List.fromList(address.rawAddress); |
| } |
| } |
| |
| /// A Service record, capturing a host target and port (DNS "SRV"). |
| class SrvResourceRecord extends ResourceRecord { |
| /// Creates a new service record. |
| const SrvResourceRecord( |
| String name, |
| int validUntil, { |
| required this.target, |
| required this.port, |
| required this.priority, |
| required this.weight, |
| }) : super(ResourceRecordType.service, name, validUntil); |
| |
| /// The hostname for this record. |
| final String target; |
| |
| /// The port for this record. |
| final int port; |
| |
| /// The relative priority of this service. |
| final int priority; |
| |
| /// The weight (used when multiple services have the same priority). |
| final int weight; |
| |
| @override |
| String get _additionalInfo => |
| 'target: $target, port: $port, priority: $priority, weight: $weight'; |
| |
| @override |
| int get hashCode => |
| Object.hash(target, port, priority, weight, super.hashCode); |
| |
| @override |
| bool operator ==(Object other) { |
| return super == other && |
| other is SrvResourceRecord && |
| other.target == target && |
| other.port == port && |
| other.priority == priority && |
| other.weight == weight; |
| } |
| |
| @override |
| Uint8List encodeResponseRecord() { |
| final List<int> data = utf8.encode(target); |
| final Uint8List result = Uint8List(data.length + 7); |
| final ByteData resultData = ByteData.view(result.buffer); |
| resultData.setUint16(0, priority); |
| resultData.setUint16(2, weight); |
| resultData.setUint16(4, port); |
| result[6] = data.length; |
| return result..setRange(7, data.length, data); |
| } |
| } |
| |
| /// A Text record, contianing additional textual data (DNS "TXT"). |
| class TxtResourceRecord extends ResourceRecord { |
| /// Creates a new text record. |
| const TxtResourceRecord( |
| String name, |
| int validUntil, { |
| required this.text, |
| }) : super(ResourceRecordType.text, name, validUntil); |
| |
| /// The raw text from this record. |
| final String text; |
| |
| @override |
| String get _additionalInfo => 'text: $text'; |
| |
| @override |
| int get hashCode => Object.hash(text.hashCode, super.hashCode); |
| |
| @override |
| bool operator ==(Object other) => |
| super == other && other is TxtResourceRecord && other.text == text; |
| |
| @override |
| Uint8List encodeResponseRecord() { |
| return Uint8List.fromList(utf8.encode(text)); |
| } |
| } |