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Add macOS IP_BOUND_IF/IPV6_BOUND_IF socket binding for interface-specific UDP listeners #2040

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Add macOS IP_BOUND_IF/IPV6_BOUND_IF socket binding for interface-specific UDP listeners #2040

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102 changes: 90 additions & 12 deletions DnsServerCore/Dns/DnsServer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ You should have received a copy of the GNU General Public License
using System.Net.Mail;
using System.Net.Quic;
using System.Net.Security;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Runtime.ExceptionServices;
using System.Runtime.InteropServices;
Expand Down Expand Up @@ -98,6 +99,11 @@ enum ServiceState
const int SOL_SOCKET = 1;
const int SO_BINDTODEVICE = 25;

const int IPPROTO_IP = 0;
const int IP_BOUND_IF = 25;
const int IPPROTO_IPV6 = 41;
const int IPV6_BOUND_IF = 125;

readonly static char[] commaSeparator = new char[] { ',' };

internal const int MAX_CNAME_HOPS = 16;
Expand Down Expand Up @@ -1718,6 +1724,20 @@ private Socket GetUdpListenerSocket(AddressFamily addressFamily)
return udpListener;
}

private static int GetInterfaceIndex(string interfaceName)
{
foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
{
if (ni.Name.Equals(interfaceName, StringComparison.Ordinal))
{
IPInterfaceProperties ipProps = ni.GetIPProperties();
return ipProps.GetIPv4Properties()?.Index ?? ipProps.GetIPv6Properties()?.Index ?? 0;
}
}

return 0;
}

private async Task ReadUdpRequestAsync(Socket udpListener, DnsTransportProtocol protocol)
{
bool sendTruncationResponse;
Expand Down Expand Up @@ -6647,16 +6667,45 @@ public async Task StartAsync(bool throwIfBindFails = false)
{
udpListener = GetUdpListenerSocket(localEP.AddressFamily);

if ((localEP is InterfaceEndPoint intEP) && (intEP.InterfaceName is not null) && RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
if (localEP is InterfaceEndPoint intEP && intEP.InterfaceName is not null)
{
try
if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
{
udpListener.SetRawSocketOption(SOL_SOCKET, SO_BINDTODEVICE, Encoding.ASCII.GetBytes(intEP.InterfaceName));
_log.Write(localEP, DnsTransportProtocol.Udp, $"Socket was bound to device '{intEP.InterfaceName}' successfully.");
try
{
udpListener.SetRawSocketOption(SOL_SOCKET, SO_BINDTODEVICE, Encoding.ASCII.GetBytes(intEP.InterfaceName));
_log.Write(localEP, DnsTransportProtocol.Udp, $"Socket was bound to device '{intEP.InterfaceName}' successfully.");
}
catch (Exception ex)
{
_log.Write(ex);
}
}
catch (Exception ex)
else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
{
_log.Write(ex);
try
{
int interfaceIndex = GetInterfaceIndex(intEP.InterfaceName);
if (interfaceIndex > 0)
{
byte[] interfaceIndexBytes = BitConverter.GetBytes(interfaceIndex);

if (localEP.AddressFamily == AddressFamily.InterNetwork)
udpListener.SetRawSocketOption(IPPROTO_IP, IP_BOUND_IF, interfaceIndexBytes);
else
udpListener.SetRawSocketOption(IPPROTO_IPV6, IPV6_BOUND_IF, interfaceIndexBytes);

_log.Write(localEP, DnsTransportProtocol.Udp, $"Socket was bound to interface '{intEP.InterfaceName}' (index {interfaceIndex}) successfully.");
}
else
{
_log.Write(localEP, DnsTransportProtocol.Udp, $"Failed to bind socket to interface '{intEP.InterfaceName}': interface not found.");
}
}
catch (Exception ex)
{
_log.Write(ex);
}
}
}

Expand Down Expand Up @@ -6701,16 +6750,45 @@ public async Task StartAsync(bool throwIfBindFails = false)
{
udpProxyListener = GetUdpListenerSocket(udpProxyEP.AddressFamily);

if ((localEP is InterfaceEndPoint intEP) && (intEP.InterfaceName is not null) && RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
if (localEP is InterfaceEndPoint intEP && intEP.InterfaceName is not null)
{
try
if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
{
udpProxyListener.SetRawSocketOption(SOL_SOCKET, SO_BINDTODEVICE, Encoding.ASCII.GetBytes(intEP.InterfaceName));
_log.Write(udpProxyEP, DnsTransportProtocol.UdpProxy, $"Socket was bound to device '{intEP.InterfaceName}' successfully.");
try
{
udpProxyListener.SetRawSocketOption(SOL_SOCKET, SO_BINDTODEVICE, Encoding.ASCII.GetBytes(intEP.InterfaceName));
_log.Write(udpProxyEP, DnsTransportProtocol.UdpProxy, $"Socket was bound to device '{intEP.InterfaceName}' successfully.");
}
catch (Exception ex)
{
_log.Write(ex);
}
}
catch (Exception ex)
else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
{
_log.Write(ex);
try
{
int interfaceIndex = GetInterfaceIndex(intEP.InterfaceName);
if (interfaceIndex > 0)
{
byte[] interfaceIndexBytes = BitConverter.GetBytes(interfaceIndex);

if (udpProxyEP.AddressFamily == AddressFamily.InterNetwork)
udpProxyListener.SetRawSocketOption(IPPROTO_IP, IP_BOUND_IF, interfaceIndexBytes);
else
udpProxyListener.SetRawSocketOption(IPPROTO_IPV6, IPV6_BOUND_IF, interfaceIndexBytes);

_log.Write(udpProxyEP, DnsTransportProtocol.UdpProxy, $"Socket was bound to interface '{intEP.InterfaceName}' (index {interfaceIndex}) successfully.");
}
else
{
_log.Write(udpProxyEP, DnsTransportProtocol.UdpProxy, $"Failed to bind socket to interface '{intEP.InterfaceName}': interface not found.");
}
}
catch (Exception ex)
{
_log.Write(ex);
}
}
}

Expand Down