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WeightedRoundRobin: added new app.

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This commit is contained in:
Shreyas Zare
2023-05-27 13:28:37 +05:30
parent 9d8a2deaba
commit 7af52d1f3e
4 changed files with 398 additions and 0 deletions
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196
Apps/WeightedRoundRobinApp/Address.cs Normal file
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/*
Technitium DNS Server
Copyright (C) 2023 Shreyas Zare (shreyas@technitium.com)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
using DnsServerCore.ApplicationCommon;
using System;
using System.Collections.Generic;
using System.Net;
using System.Security.Cryptography;
using System.Text.Json;
using System.Threading.Tasks;
using TechnitiumLibrary.Net.Dns;
using TechnitiumLibrary.Net.Dns.ResourceRecords;
namespace WeightedRoundRobin
{
public class Address : IDnsApplication, IDnsAppRecordRequestHandler
{
#region IDisposable
public void Dispose()
{
//do nothing
}
#endregion
#region public
public Task InitializeAsync(IDnsServer dnsServer, string config)
{
return Task.CompletedTask;
}
public Task<DnsDatagram> ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, bool isRecursionAllowed, string zoneName, string appRecordName, uint appRecordTtl, string appRecordData)
{
DnsQuestionRecord question = request.Question[0];
if (!question.Name.Equals(appRecordName, StringComparison.OrdinalIgnoreCase))
return Task.FromResult<DnsDatagram>(null);
string jsonPropertyName;
switch (question.Type)
{
case DnsResourceRecordType.A:
jsonPropertyName = "ipv4Addresses";
break;
case DnsResourceRecordType.AAAA:
jsonPropertyName = "ipv6Addresses";
break;
default:
return Task.FromResult<DnsDatagram>(null);
}
List<WeightedAddress> addresses;
int totalWeight = 0;
using (JsonDocument jsonDocument = JsonDocument.Parse(appRecordData))
{
JsonElement jsonAppRecordData = jsonDocument.RootElement;
if (!jsonAppRecordData.TryGetProperty(jsonPropertyName, out JsonElement jsonAddresses) || (jsonAddresses.ValueKind == JsonValueKind.Null))
return Task.FromResult<DnsDatagram>(null);
addresses = new List<WeightedAddress>(jsonAddresses.GetArrayLength());
foreach (JsonElement jsonAddressEntry in jsonAddresses.EnumerateArray())
{
if (jsonAddressEntry.TryGetProperty("enabled", out JsonElement jsonEnabled) && (jsonEnabled.ValueKind != JsonValueKind.Null) && !jsonEnabled.GetBoolean())
continue;
if (!jsonAddressEntry.TryGetProperty("address", out JsonElement jsonAddress) || (jsonAddress.ValueKind == JsonValueKind.Null) || !IPAddress.TryParse(jsonAddress.GetString(), out IPAddress address))
continue;
if (!jsonAddressEntry.TryGetProperty("weight", out JsonElement jsonWeight) || (jsonWeight.ValueKind == JsonValueKind.Null))
continue;
int weight = jsonWeight.GetInt32();
if (weight < 1)
continue;
addresses.Add(new WeightedAddress() { Address = address, Weight = weight });
totalWeight += weight;
}
}
if (addresses.Count == 0)
return Task.FromResult<DnsDatagram>(null);
int randomSelection = RandomNumberGenerator.GetInt32(1, 101);
int rangeFrom;
int rangeTo = 0;
DnsResourceRecord answer = null;
for (int i = 0; i < addresses.Count; i++)
{
rangeFrom = rangeTo + 1;
if (i == addresses.Count - 1)
rangeTo = 100;
else
rangeTo += addresses[i].Weight * 100 / totalWeight;
if ((rangeFrom <= randomSelection) && (randomSelection <= rangeTo))
{
switch (question.Type)
{
case DnsResourceRecordType.A:
answer = new DnsResourceRecord(question.Name, question.Type, DnsClass.IN, appRecordTtl, new DnsARecordData(addresses[i].Address));
break;
case DnsResourceRecordType.AAAA:
answer = new DnsResourceRecord(question.Name, question.Type, DnsClass.IN, appRecordTtl, new DnsAAAARecordData(addresses[i].Address));
break;
default:
throw new InvalidOperationException();
}
break;
}
}
if (answer is null)
throw new InvalidOperationException();
return Task.FromResult(new DnsDatagram(request.Identifier, true, request.OPCODE, true, false, request.RecursionDesired, isRecursionAllowed, false, false, DnsResponseCode.NoError, request.Question, new DnsResourceRecord[] { answer }));
}
#endregion
#region properties
public string Description
{ get { return "Returns an A or AAAA record using weighted round-robin load balancing."; } }
public string ApplicationRecordDataTemplate
{
get
{
return @"{
""ipv4Addresses"": [
{
""address"": ""1.1.1.1"",
""weight"": 5,
""enabled"": true
},
{
""address"": ""2.2.2.2"",
""weight"": 3,
""enabled"": true
}
],
""ipv6Addresses"": [
{
""address"": ""::1"",
""weight"": 2,
""enabled"": true
},
{
""address"": ""::2"",
""weight"": 3,
""enabled"": true
}
]
}";
}
}
#endregion
struct WeightedAddress
{
public IPAddress Address;
public int Weight;
}
}
}

159
Apps/WeightedRoundRobinApp/CNAME.cs Normal file
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/*
Technitium DNS Server
Copyright (C) 2023 Shreyas Zare (shreyas@technitium.com)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
using DnsServerCore.ApplicationCommon;
using System;
using System.Collections.Generic;
using System.Net;
using System.Security.Cryptography;
using System.Text.Json;
using System.Threading.Tasks;
using TechnitiumLibrary.Net.Dns;
using TechnitiumLibrary.Net.Dns.ResourceRecords;
namespace WeightedRoundRobin
{
public class CNAME : IDnsApplication, IDnsAppRecordRequestHandler
{
#region IDisposable
public void Dispose()
{
//do nothing
}
#endregion
#region public
public Task InitializeAsync(IDnsServer dnsServer, string config)
{
return Task.CompletedTask;
}
public Task<DnsDatagram> ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, bool isRecursionAllowed, string zoneName, string appRecordName, uint appRecordTtl, string appRecordData)
{
DnsQuestionRecord question = request.Question[0];
if (!question.Name.Equals(appRecordName, StringComparison.OrdinalIgnoreCase))
return Task.FromResult<DnsDatagram>(null);
List<WeightedDomain> domainNames;
int totalWeight = 0;
using (JsonDocument jsonDocument = JsonDocument.Parse(appRecordData))
{
JsonElement jsonAppRecordData = jsonDocument.RootElement;
if (!jsonAppRecordData.TryGetProperty("cnames", out JsonElement jsonCnames) || (jsonCnames.ValueKind == JsonValueKind.Null))
return Task.FromResult<DnsDatagram>(null);
domainNames = new List<WeightedDomain>(jsonCnames.GetArrayLength());
foreach (JsonElement jsonCnameEntry in jsonCnames.EnumerateArray())
{
if (jsonCnameEntry.TryGetProperty("enabled", out JsonElement jsonEnabled) && (jsonEnabled.ValueKind != JsonValueKind.Null) && !jsonEnabled.GetBoolean())
continue;
if (!jsonCnameEntry.TryGetProperty("domain", out JsonElement jsonDomain) || (jsonDomain.ValueKind == JsonValueKind.Null))
continue;
if (!jsonCnameEntry.TryGetProperty("weight", out JsonElement jsonWeight) || (jsonWeight.ValueKind == JsonValueKind.Null))
continue;
int weight = jsonWeight.GetInt32();
if (weight < 1)
continue;
domainNames.Add(new WeightedDomain() { Domain = jsonDomain.GetString(), Weight = weight });
totalWeight += weight;
}
}
if (domainNames.Count == 0)
return Task.FromResult<DnsDatagram>(null);
int randomSelection = RandomNumberGenerator.GetInt32(1, 101);
int rangeFrom;
int rangeTo = 0;
DnsResourceRecord answer = null;
for (int i = 0; i < domainNames.Count; i++)
{
rangeFrom = rangeTo + 1;
if (i == domainNames.Count - 1)
rangeTo = 100;
else
rangeTo += domainNames[i].Weight * 100 / totalWeight;
if ((rangeFrom <= randomSelection) && (randomSelection <= rangeTo))
{
if (question.Name.Equals(zoneName, StringComparison.OrdinalIgnoreCase)) //check for zone apex
answer = new DnsResourceRecord(question.Name, DnsResourceRecordType.ANAME, DnsClass.IN, appRecordTtl, new DnsANAMERecordData(domainNames[i].Domain)); //use ANAME
else
answer = new DnsResourceRecord(question.Name, DnsResourceRecordType.CNAME, DnsClass.IN, appRecordTtl, new DnsCNAMERecordData(domainNames[i].Domain));
break;
}
}
if (answer is null)
throw new InvalidOperationException();
return Task.FromResult(new DnsDatagram(request.Identifier, true, request.OPCODE, true, false, request.RecursionDesired, isRecursionAllowed, false, false, DnsResponseCode.NoError, request.Question, new DnsResourceRecord[] { answer }));
}
#endregion
#region properties
public string Description
{ get { return "Returns a CNAME record using weighted round-robin load balancing."; } }
public string ApplicationRecordDataTemplate
{
get
{
return @"{
""cnames"": [
{
""domain"": ""example.com"",
""weight"": 5,
""enabled"": true
},
{
""domain"": ""example.net"",
""weight"": 3,
""enabled"": true
}
]
}";
}
}
#endregion
struct WeightedDomain
{
public string Domain;
public int Weight;
}
}
}

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Apps/WeightedRoundRobinApp/WeightedRoundRobinApp.csproj Normal file
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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net7.0</TargetFramework>
<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
<Version>1.0</Version>
<Company>Technitium</Company>
<Product>Technitium DNS Server</Product>
<Authors>Shreyas Zare</Authors>
<AssemblyName>WeightedRoundRobinApp</AssemblyName>
<RootNamespace>WeightedRoundRobin</RootNamespace>
<PackageProjectUrl>https://technitium.com/dns/</PackageProjectUrl>
<RepositoryUrl>https://github.com/TechnitiumSoftware/DnsServer</RepositoryUrl>
<Description>Allows creating APP records in a primary and forwarder zones that can return A or AAAA records, or CNAME record using weighted round-robin load balancing.</Description>
<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
<OutputType>Library</OutputType>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\..\DnsServerCore.ApplicationCommon\DnsServerCore.ApplicationCommon.csproj">
<Private>false</Private>
</ProjectReference>
</ItemGroup>
<ItemGroup>
<Reference Include="TechnitiumLibrary">
<HintPath>..\..\..\TechnitiumLibrary\bin\TechnitiumLibrary.dll</HintPath>
<Private>false</Private>
</Reference>
<Reference Include="TechnitiumLibrary.Net">
<HintPath>..\..\..\TechnitiumLibrary\bin\TechnitiumLibrary.Net.dll</HintPath>
<Private>false</Private>
</Reference>
</ItemGroup>
<ItemGroup>
<None Update="dnsApp.config">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
</ItemGroup>
</Project>

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Apps/WeightedRoundRobinApp/dnsApp.config Normal file
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#This app requires no config.