From a7c4a365e864256728b49bd1cddda154ef00f9ef Mon Sep 17 00:00:00 2001
From: rinrab <tima@chemodax.net>
Date: Sat, 20 Jan 2024 18:49:57 +0100
Subject: [PATCH] Create `RasApi.DisconnectAll()` function.

---
 AOVpnManager.Tests/RasApiTests.cs | 25 +++++++++++
 AOVpnManager/RasApi.cs            | 74 +++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)
 create mode 100644 AOVpnManager.Tests/RasApiTests.cs
 create mode 100644 AOVpnManager/RasApi.cs

diff --git a/AOVpnManager.Tests/RasApiTests.cs b/AOVpnManager.Tests/RasApiTests.cs
new file mode 100644
index 0000000..fdb81bc
--- /dev/null
+++ b/AOVpnManager.Tests/RasApiTests.cs
@@ -0,0 +1,25 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Diagnostics;
+
+namespace AOVpnManager.Tests
+{
+    [TestClass]
+    public class RasApiTests
+    {
+        [TestMethod]
+        public void HangupAllTest()
+        {
+            if (!Debugger.IsAttached)
+            {
+                return;
+            }
+
+            RasApi.DisconnectAll((x) =>
+            {
+                Console.WriteLine(x);
+                return true;
+            });
+        }
+    }
+}
diff --git a/AOVpnManager/RasApi.cs b/AOVpnManager/RasApi.cs
new file mode 100644
index 0000000..50ffdee
--- /dev/null
+++ b/AOVpnManager/RasApi.cs
@@ -0,0 +1,74 @@
+using System;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+
+namespace AOVpnManager
+{
+    public static class RasApi
+    {
+        public static void DisconnectAll(Predicate<string> filter)
+        {
+            uint dwSize = (uint)Marshal.SizeOf(typeof(RASCONN));
+            uint count = 1;
+            RASCONN[] connections;
+            while (true)
+            {
+                uint cb = dwSize * count;
+                connections = new RASCONN[count];
+                connections[0].dwSize = dwSize;
+
+                int err = RasEnumConnections(connections, ref cb, ref count);
+
+                if (err == 0)
+                {
+                    break;
+                }
+                else if (err != ERROR_BUFFER_TOO_SMALL)
+                {
+                    throw new Win32Exception(err);
+                }
+
+                count = (cb + dwSize - 1) / dwSize;
+            }
+
+            for (int i = 0; i < count; i++)
+            {
+                if (filter(connections[i].szEntryName))
+                {
+                    RasHangUp(connections[i].hrasconn);
+                }
+            }
+        }
+
+        const int RAS_MaxEntryName = 256;
+        const int RAS_MaxDeviceType = 16;
+        const int RAS_MaxDeviceName = 128;
+
+        const int ERROR_BUFFER_TOO_SMALL = 603;
+
+        [StructLayout(LayoutKind.Sequential, Pack = 4, CharSet = CharSet.Auto)]
+        private struct RASCONN
+        {
+            public uint dwSize;
+
+            public IntPtr hrasconn;
+
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxEntryName + 1)]
+            public string szEntryName;
+
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceType + 1)]
+            public string szDeviceType;
+
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceName + 1)]
+            public string szDeviceName;
+
+            // We don't care about other feilds.
+        }
+
+        [DllImport("Rasapi32.dll", ExactSpelling = false, CharSet = CharSet.Auto, SetLastError = false)]
+        private static extern int RasEnumConnections([In, Out] RASCONN[] connections, ref uint cb, ref uint count);
+
+        [DllImport("Rasapi32.dll", ExactSpelling = false, CharSet = CharSet.Auto, SetLastError = false)]
+        private static extern int RasHangUp(IntPtr rasconn);
+    }
+}