Linux Tap Support (#335)

.appveyor.yml

@@ -29,7 +29,7 @@ for:
   build_script:
     - dotnet build -c Release
   test_script:
-    - bash scripts/test.sh --filter "TestCategory!=Performance&TestCategory!=RemotePcap&TestCategory!=WinDivert&TestCategory!=WinpkFilter&TestCategory!=WinTap"
+    - bash scripts/test.sh --filter "TestCategory!=Performance&TestCategory!=RemotePcap&TestCategory!=WinDivert&TestCategory!=WinpkFilter"
 
 -
   matrix:
@@ -42,7 +42,7 @@ for:
   build_script:
     - dotnet build -c Release
   test_script:
-    - bash scripts/test.sh --filter "TestCategory!=RemotePcap&TestCategory!=WinDivert&TestCategory!=WinTap"
+    - bash scripts/test.sh --filter "TestCategory!=RemotePcap&TestCategory!=WinDivert"
 
 -
   matrix:
@@ -51,7 +51,7 @@ for:
   install:
     - sudo -E bash scripts/install-libpcap.sh
   test_script:
-    - sudo -E bash scripts/test.sh
+    - sudo -E bash scripts/test.sh --filter "TestCategory!=Tunneling"
 
 -
   matrix:

.circleci/config.yml

@@ -25,6 +25,7 @@ jobs:
     steps:
       - checkout
       - run: sudo -E bash scripts/install-dotnet.sh
+      - run: sudo -E bash scripts/install-tap.sh
       # Download and compile latest libpcap
       - when:
           condition: { equal: [ libpcap-script, << parameters.libpcap >> ] }

.github/workflows/dotnet-core.yml

@@ -21,6 +21,8 @@ jobs:
       run: dotnet restore
     - name: Install libpcap
       run: sudo -E bash scripts/install-libpcap.sh
+    - name: Install tap
+      run: sudo -E bash scripts/install-tap.sh
     - name: Build sharppcap assembly
       run: dotnet build SharpPcap/SharpPcap.csproj
     - name: Test

.semaphore/semaphore.yml

@@ -20,6 +20,7 @@ blocks:
         - commands:
             - checkout
             - sudo -E bash scripts/install-libpcap.sh
+            - sudo -E bash scripts/install-tap.sh
             - sudo -E bash scripts/install-dotnet.sh
             - sudo -E bash scripts/test.sh --filter "TestCategory!=Performance"
           name: Test

SharpPcap/ARP.cs

@@ -111,79 +111,88 @@ public PhysicalAddress Resolve(System.Net.IPAddress destIP,
             {
                 throw new InvalidOperationException("Unable to find local mac address");
             }
+            using (var device = new LibPcapLiveDevice(pcapInterface))
+            {
+                //open the device with 20ms timeout
+                device.Open(mode: DeviceModes.Promiscuous, read_timeout: 20);
+                return Resolve(device, destIP, localIP, localMAC, Timeout);
+            }
+        }
 
+        internal static PhysicalAddress Resolve(
+            ILiveDevice device,
+            System.Net.IPAddress destIP,
+            System.Net.IPAddress localIP,
+            PhysicalAddress localMAC,
+            TimeSpan timeout)
+        {
             //Build a new ARP request packet
             var request = BuildRequest(destIP, localMAC, localIP);
 
             //create a "tcpdump" filter for allowing only arp replies to be read
             String arpFilter = "arp and ether dst " + localMAC.ToString();
 
-            using (var device = new LibPcapLiveDevice(pcapInterface))
-            {
-                //open the device with 20ms timeout
-                device.Open(mode: DeviceModes.Promiscuous, read_timeout: 20);
+            //set the filter
+            device.Filter = arpFilter;
 
-                //set the filter
-                device.Filter = arpFilter;
+            // set a last request time that will trigger sending the
+            // arp request immediately
+            var lastRequestTime = DateTime.FromBinary(0);
 
-                // set a last request time that will trigger sending the
-                // arp request immediately
-                var lastRequestTime = DateTime.FromBinary(0);
+            var requestInterval = new TimeSpan(0, 0, 1);
 
-                var requestInterval = new TimeSpan(0, 0, 1);
+            PacketDotNet.ArpPacket arpPacket = null;
 
-                PacketDotNet.ArpPacket arpPacket = null;
-
-                // attempt to resolve the address with the current timeout
-                var timeoutDateTime = DateTime.Now + Timeout;
-                while (DateTime.Now < timeoutDateTime)
+            // attempt to resolve the address with the current timeout
+            var timeoutDateTime = DateTime.Now + timeout;
+            while (DateTime.Now < timeoutDateTime)
+            {
+                if (requestInterval < (DateTime.Now - lastRequestTime))
                 {
-                    if (requestInterval < (DateTime.Now - lastRequestTime))
-                    {
-                        // inject the packet to the wire
-                        device.SendPacket(request);
-                        lastRequestTime = DateTime.Now;
-                    }
-
-                    //read the next packet from the network
-                    var retval = device.GetNextPacket(out PacketCapture e);
-                    if (retval != GetPacketStatus.PacketRead)
-                    {
-                        continue;
-                    }
-                    var reply = e.GetPacket();
-
-                    // parse the packet
-                    var packet = PacketDotNet.Packet.ParsePacket(reply.LinkLayerType, reply.Data);
-
-                    // is this an arp packet?
-                    arpPacket = packet.Extract<PacketDotNet.ArpPacket>();
-                    if (arpPacket == null)
-                    {
-                        continue;
-                    }
+                    // inject the packet to the wire
+                    device.SendPacket(request);
+                    lastRequestTime = DateTime.Now;
+                }
 
-                    //if this is the reply we're looking for, stop
-                    if (arpPacket.SenderProtocolAddress.Equals(destIP))
-                    {
-                        break;
-                    }
+                //read the next packet from the network
+                var retval = device.GetNextPacket(out PacketCapture e);
+                if (retval != GetPacketStatus.PacketRead)
+                {
+                    continue;
                 }
+                var reply = e.GetPacket();
 
-                // the timeout happened
-                if (DateTime.Now >= timeoutDateTime)
+                // parse the packet
+                var packet = PacketDotNet.Packet.ParsePacket(reply.LinkLayerType, reply.Data);
+
+                // is this an arp packet?
+                arpPacket = packet.Extract<PacketDotNet.ArpPacket>();
+                if (arpPacket == null)
                 {
-                    return null;
+                    continue;
                 }
-                else
+
+                //if this is the reply we're looking for, stop
+                if (arpPacket.SenderProtocolAddress.Equals(destIP))
                 {
-                    //return the resolved MAC address
-                    return arpPacket.SenderHardwareAddress;
+                    break;
                 }
             }
+
+            // the timeout happened
+            if (DateTime.Now >= timeoutDateTime)
+            {
+                return null;
+            }
+            else
+            {
+                //return the resolved MAC address
+                return arpPacket.SenderHardwareAddress;
+            }
         }
 
-        private PacketDotNet.Packet BuildRequest(System.Net.IPAddress destinationIP,
+
+        private static PacketDotNet.Packet BuildRequest(System.Net.IPAddress destinationIP,
                                                  PhysicalAddress localMac,
                                                  System.Net.IPAddress localIP)
         {

SharpPcap/BaseLiveDevice.cs

@@ -82,14 +82,16 @@ protected void RaiseOnPacketArrival(PacketCapture capture)
         public GetPacketStatus GetNextPacket(out PacketCapture e)
         {
             var sw = Stopwatch.StartNew();
-            do
+            var timeout = ReadTimeout - sw.Elapsed;
+            while (timeout.TotalMilliseconds > 0)
             {
-                var status = GetUnfilteredPacket(out e, ReadTimeout - sw.Elapsed);
+                var status = GetUnfilteredPacket(out e, timeout);
                 if (FilterProgram?.Matches(e.Data) ?? true)
                 {
                     return status;
                 }
-            } while (sw.Elapsed < ReadTimeout);
+                timeout = ReadTimeout - sw.Elapsed;
+            }
             e = default;
             return GetPacketStatus.ReadTimeout;
         }

SharpPcap/LibPcap/PcapDeviceCaptureLoop.cs

@@ -66,7 +66,18 @@ public virtual void StartCapture()
                     throw new DeviceNotReadyException("No delegates assigned to OnPacketArrival, no where for captured packets to go.");
 
                 var cancellationToken = threadCancellationTokenSource.Token;
-                captureThread = new Thread(() => this.CaptureThread(cancellationToken));
+                captureThread = new Thread(() =>
+                {
+                    try
+                    {
+                        CaptureThread(cancellationToken);
+                    }
+                    catch
+                    {
+                        // a thread is not allowed to throw, otherwise it causes system crash
+                        // most common case is misuse of API or concurent access to device
+                    }
+                });
                 captureThread.Start();
             }
         }

SharpPcap/LibPcap/PcapUnmanagedStructures.cs

@@ -95,10 +95,9 @@ public struct sockaddr_in
             //       understand way
 
             // pad the size of sockaddr_in out to 16 bytes
-            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
             // Disable warnings around this unused field
 #pragma warning disable 0169
-            private readonly byte[] pad;
+            private readonly ulong pad;
 #pragma warning restore 0169
         };
 

SharpPcap/Tunneling/IPAddressConfiguration.cs

@@ -0,0 +1,14 @@
+using System.Net;
+
+namespace SharpPcap.Tunneling
+{
+    /// <summary>
+    /// IP Address configuration of the tunnel interface
+    /// </summary>
+    public class IPAddressConfiguration
+    {
+        // property names based on UnicastIPAddressInformation
+        public IPAddress Address { get; set; }
+        public IPAddress IPv4Mask { get; set; }
+    }
+}

SharpPcap/Tunneling/ITunnelDriver.cs

@@ -0,0 +1,15 @@
+using Microsoft.Win32.SafeHandles;
+using System;
+using System.IO;
+using System.Net.NetworkInformation;
+
+namespace SharpPcap.Tunneling
+{
+    internal interface ITunnelDriver
+    {
+        bool IsTunnelInterface(NetworkInterface networkInterface);
+        FileStream Open(NetworkInterface networkInterface, IPAddressConfiguration address, DeviceConfiguration configuration);
+        Version GetVersion(NetworkInterface networkInterface, SafeFileHandle handle);
+    }
+
+}