avoid allocations in SendTo and Quic

src/libraries/Common/src/Interop/BSD/System.Native/Interop.SocketAddress.cs

@@ -0,0 +1,42 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in
+        {
+            public byte sin_len;
+            public byte sin_family;
+            public ushort sin_port;
+            public fixed byte sin_addr[4];
+            private fixed byte sin_zero[8];
+
+            public void SetAddressFamily(int family)
+            {
+                sin_family = (byte)family;
+            }
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in6
+        {
+            public byte sin_len;
+            public byte sin6_family;
+            public ushort sin6_port;
+            public uint sin6_flowinfo;
+            public fixed byte sin6_addr[16];
+            public uint sin6_scope_id;
+
+            public void SetAddressFamily(int family)
+            {
+                sin6_family = (byte)family;
+            }
+        }
+    }
+}

src/libraries/Common/src/Interop/FreeBSD/System.Native/Interop.SocketAddress.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        internal const int AF_INET = 2;
+        internal const int AF_INET6 = 28;
+    }
+}

src/libraries/Common/src/Interop/Linux/System.Native/Interop.SocketAddress.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        internal const int AF_INET = 2;
+        internal const int AF_INET6 = 10;
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in
+        {
+            public ushort sin_family;
+            public ushort sin_port;
+            public fixed byte sin_addr[4];
+            private fixed byte sin_zero[8];
+
+            public void SetAddressFamily(int family)
+            {
+                sin_family = (ushort)family;
+            }
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in6
+        {
+            public ushort sin6_family;
+            public ushort sin6_port;
+            public uint sin6_flowinfo;
+            public fixed byte sin6_addr[16];
+            public uint sin6_scope_id;
+
+            public void SetAddressFamily(int family)
+            {
+                sin6_family = (ushort)family;
+            }
+        }
+    }
+}

src/libraries/Common/src/Interop/OSX/System.Native/Interop.SocketAddress.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        internal const int AF_INET = 2;
+        internal const int AF_INET6 = 30;
+    }
+}

src/libraries/Common/src/Interop/Windows/WinSock/Interop.SocketAddress.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        internal const int AF_INET = 2;
+        internal const int AF_INET6 = 23;
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in
+        {
+            public ushort sin_family;
+            public ushort sin_port;
+            public fixed byte sin_addr[4];
+            private fixed byte sin_zero[8];
+
+            public void SetAddressFamily(int family)
+            {
+                sin_family = (ushort)family;
+            }
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal unsafe struct sockaddr_in6
+        {
+            public ushort sin6_family;
+            public ushort sin6_port;
+            public uint sin6_flowinfo;
+            public fixed byte sin6_addr[16];
+            public uint sin6_scope_id;
+
+            public void SetAddressFamily(int family)
+            {
+                sin6_family = (ushort)family;
+            }
+        }
+    }
+}

src/libraries/Common/src/Interop/Windows/WinSock/Interop.WSASendTo.cs

@@ -18,7 +18,7 @@ private static unsafe partial SocketError WSASendTo(
             int bufferCount,
             out int bytesTransferred,
             SocketFlags socketFlags,
-            IntPtr socketAddress,
+            byte* socketAddress,
             int socketAddressSize,
             NativeOverlapped* overlapped,
             IntPtr completionRoutine);
@@ -29,7 +29,7 @@ internal static unsafe SocketError WSASendTo(
             int bufferCount,
             out int bytesTransferred,
             SocketFlags socketFlags,
-            IntPtr socketAddress,
+            byte* socketAddress,
             int socketAddressSize,
             NativeOverlapped* overlapped,
             IntPtr completionRoutine)
@@ -47,7 +47,7 @@ internal static unsafe SocketError WSASendTo(
             int bufferCount,
             [Out] out int bytesTransferred,
             SocketFlags socketFlags,
-            IntPtr socketAddress,
+            byte* socketAddress,
             int socketAddressSize,
             NativeOverlapped* overlapped,
             IntPtr completionRoutine)

src/libraries/Common/src/Interop/Windows/WinSock/Interop.sendto.cs

@@ -17,5 +17,14 @@ internal static unsafe partial int sendto(
             SocketFlags socketFlags,
             byte[] socketAddress,
             int socketAddressSize);
+
+        [LibraryImport(Interop.Libraries.Ws2_32, SetLastError = true)]
+        internal static unsafe partial int sendto(
+           SafeSocketHandle socketHandle,
+           byte* pinnedBuffer,
+           int len,
+           SocketFlags socketFlags,
+           ReadOnlySpan<byte> socketAddress,
+           int socketAddressSize);
     }
 }

src/libraries/Common/src/System/Net/SockAddr.cs

@@ -0,0 +1,150 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+
+namespace System.Net.Sockets
+{
+    [StructLayout(LayoutKind.Explicit)]
+    internal partial struct SockAddr
+    {
+        internal const int IPv4AddressSize = 4;
+        internal const int IPv6AddressSize = 16;
+
+        private static ReadOnlySpan<byte> V4MappedPrefix=> new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff};
+
+        [FieldOffset(0)]
+        public Interop.Sys.sockaddr_in Ipv4;
+        [FieldOffset(0)]
+        public Interop.Sys.sockaddr_in6 Ipv6;
+
+        public int Family => Ipv4.sin_family;
+
+        public unsafe SockAddr(IPEndPoint endPoint) : this(endPoint, endPoint.Address.AddressFamily)
+        {
+        }
+
+        public unsafe SockAddr(IPEndPoint endPoint, AddressFamily addressFamily)
+        {
+            if (addressFamily == endPoint.Address.AddressFamily)
+            {
+                if (endPoint.AddressFamily == AddressFamily.InterNetwork)
+                {
+                    Ipv4.sin_family = Interop.Sys.AF_INET;
+                    Ipv4.sin_port = (ushort)IPAddress.HostToNetworkOrder((short)endPoint.Port);
+                    Span<byte> address = MemoryMarshal.CreateSpan(ref Ipv4.sin_addr[0], IPv4AddressSize);
+                    if (!endPoint.Address.TryWriteBytes(address, out int bytesWritten) || bytesWritten != IPv4AddressSize)
+                    {
+                        throw new SocketException((int)SocketError.InvalidArgument);
+                    }
+                }
+                else if (endPoint.AddressFamily == AddressFamily.InterNetworkV6)
+                {
+                    Ipv6.sin6_family = Interop.Sys.AF_INET6;
+                    Ipv6.sin6_port = (ushort)IPAddress.HostToNetworkOrder((short)endPoint.Port);
+                    Span<byte> address = MemoryMarshal.CreateSpan(ref Ipv6.sin6_addr[0], IPv6AddressSize);
+                    if (!endPoint.Address.TryWriteBytes(address, out int bytesWritten) || bytesWritten != IPv6AddressSize)
+                    {
+                        throw new SocketException((int)SocketError.InvalidArgument);
+                    }
+                }
+                else
+                {
+                    // Next IP version???
+                    throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+                }
+            }
+            else if (endPoint.Address.AddressFamily == AddressFamily.InterNetwork && addressFamily == AddressFamily.InterNetworkV6)
+            {
+                // Map IPv4 to IPv4. This is currently only supported cases when AddressFamily does not match.
+                Ipv6.sin6_family = Interop.Sys.AF_INET6;
+                Ipv6.sin6_port = (ushort)IPAddress.HostToNetworkOrder((short)endPoint.Port);
+                Span<byte> address = MemoryMarshal.CreateSpan(ref Ipv6.sin6_addr[0], IPv6AddressSize);
+
+                V4MappedPrefix.CopyTo(address);
+                if (!endPoint.Address.TryWriteBytes(address.Slice(V4MappedPrefix.Length), out int bytesWritten) || bytesWritten != IPv4AddressSize)
+                {
+                    throw new SocketException((int)SocketError.InvalidArgument);
+                }
+            }
+            else
+            {
+                throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+            }
+        }
+
+        public AddressFamily AddressFamily
+        {
+            get
+            {
+                switch (Family)
+                {
+                    case Interop.Sys.AF_INET: return AddressFamily.InterNetwork;
+                    case Interop.Sys.AF_INET6: return AddressFamily.InterNetworkV6;
+                    default:
+                        throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+                }
+            }
+        }
+
+        public unsafe int Length
+        {
+            get
+            {
+                switch (Family)
+                {
+                    case Interop.Sys.AF_INET: return sizeof(Interop.Sys.sockaddr_in);
+                    case Interop.Sys.AF_INET6: return sizeof(Interop.Sys.sockaddr_in6);
+                    default:
+                        throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+                }
+            }
+        }
+
+        public unsafe ReadOnlySpan<byte> AsBytes()
+        {
+            return MemoryMarshal.AsBytes(MemoryMarshal.CreateReadOnlySpan(ref this, 1)).Slice(0, Length);
+        }
+
+        public ushort GetPort()
+        {
+            if (AddressFamily == AddressFamily.InterNetworkV6)
+            {
+                return (ushort)IPAddress.NetworkToHostOrder((short)Ipv6.sin6_port);
+            }
+            else if (AddressFamily == AddressFamily.InterNetwork)
+            {
+                return (ushort)IPAddress.NetworkToHostOrder((short)Ipv4.sin_port);
+            }
+            else
+            {
+                throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+            }
+        }
+
+        public unsafe IPAddress GetIPAddress()
+        {
+            if (AddressFamily == AddressFamily.InterNetworkV6)
+            {
+                return new IPAddress(MemoryMarshal.CreateSpan(ref Ipv6.sin6_addr[0], IPv6AddressSize), Ipv6.sin6_scope_id);
+            }
+            else if (AddressFamily == AddressFamily.InterNetwork)
+            {
+                return new IPAddress(MemoryMarshal.CreateSpan(ref Ipv4.sin_addr[0], IPv4AddressSize));
+            }
+            else
+            {
+                throw new SocketException((int)SocketError.AddressFamilyNotSupported);
+            }
+        }
+
+        public IPEndPoint GetIPEndPoint()
+        {
+            return new IPEndPoint(GetIPAddress(), GetPort());
+        }
+
+        public void SetAddressFamily(AddressFamily family) => Ipv4.SetAddressFamily((int)family);
+    }
+}