翻录filter

xljiulang · Sep 27, 2022 · 397b881 · 397b881
1 parent c84b0bc
commit 397b881
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Showing 3 changed files with 146 additions and 14 deletions.
diff --git a/App/Program.cs b/App/Program.cs
@@ -7,11 +7,16 @@ internal class Program
     {
         unsafe static void Main(string[] args)
         {
-            using var divert = new WinDivert("true", WinDivertLayer.Network);
-            using var packet = new WinDivertPacket();
-            var addr = new WinDivertAddress();
+            //using var divert = new WinDivert("((true) and (tcp)) and (tcp.Rst)", WinDivertLayer.Network);
+            // using var packet = new WinDivertPacket();
+            // var addr = new WinDivertAddress();
 
-            var filter = Filter.True().And(f => f.IsUdp == true).And(item => item.Tcp.Rst).ToFilter();
+            var filter = Filter
+                .True()
+                .And(f => !f.TcpProtocol)
+                .And(f => f.Ip.SrcAddr == System.Net.IPAddress.Loopback)
+                .And(item => item.Tcp.Rst)
+                .ToFilter();
 
             //divert.Recv(packet, ref addr);
             //var result = packet.GetParseResult();

diff --git a/WindivertDotnet/Filter.ToString.cs b/WindivertDotnet/Filter.ToString.cs
@@ -1,5 +1,7 @@
 using System;
+using System.Collections.Generic;
 using System.Linq.Expressions;
+using System.Reflection;
 using System.Text;
 
 namespace WindivertDotnet
@@ -13,13 +15,47 @@ public static string ToFilter(this Expression<Func<IFilter, bool>> expression)
             return visitor.ToString();
         }
 
-        private class FilterVisitor : ExpressionVisitor
+        private class FilterVisitor
         {
             private readonly StringBuilder builder = new();
 
-
-            protected override Expression VisitBinary(BinaryExpression node)
+            public void Visit(Expression node)
             {
+                if (node.NodeType == ExpressionType.Constant
+                    && node is ConstantExpression constantExpression)
+                {
+                    this.VisitConstant(constantExpression);
+                }
+                else if (node.NodeType == ExpressionType.MemberAccess
+                    && node is MemberExpression memberExpression)
+                {
+                    this.VisitMember(memberExpression);
+                }
+                else if (node.NodeType == ExpressionType.Lambda
+                    && node is LambdaExpression lambdaExpression)
+                {
+                    this.Visit(lambdaExpression.Body);
+                }
+                else if (node is BinaryExpression binaryExpression)
+                {
+                    this.VisitBinary(binaryExpression);
+                }
+            }
+
+            private void VisitBinary(BinaryExpression node)
+            {
+                if (node.Left is BinaryExpression leftBinaryExpression)
+                {
+                    builder.Append("(");
+                    this.VisitBinary(leftBinaryExpression);
+                    builder.Append(")");
+                }
+                else
+                {
+                    this.Visit(node.Left);
+                }
+
+
                 switch (node.NodeType)
                 {
                     case ExpressionType.And:
@@ -30,10 +66,79 @@ protected override Expression VisitBinary(BinaryExpression node)
                     case ExpressionType.Or:
                     case ExpressionType.OrElse:
                         builder.Append(" or ");
-                        break;                         
+                        break;
+
+                    case ExpressionType.Equal:
+                        builder.Append(" == ");
+                        break;
+
+                    case ExpressionType.NotEqual:
+                        builder.Append(" != ");
+                        break;
+
+                    case ExpressionType.GreaterThan:
+                        builder.Append(" > ");
+                        break;
+
+                    case ExpressionType.GreaterThanOrEqual:
+                        builder.Append(" >= ");
+                        break;
+
+                    case ExpressionType.LessThan:
+                        builder.Append(" < ");
+                        break;
+
+                    case ExpressionType.LessThanOrEqual:
+                        builder.Append(" <= ");
+                        break;
+                }
+
+                if (node.Right is BinaryExpression rightBinaryExpression)
+                {
+                    builder.Append("(");
+                    this.VisitBinary(rightBinaryExpression);
+                    builder.Append(")");
+                }
+                else
+                {
+                    this.Visit(node.Right);
+                }
+            }
+
+            private void VisitConstant(ConstantExpression node)
+            {
+                if (node.Value is bool bValue)
+                {
+                    builder.Append(bValue.ToString().ToLowerInvariant());
+                }
+                else
+                {
+                    builder.Append(node.Value?.ToString());
                 }
+            }
+
+            private void VisitMember(MemberExpression node)
+            {
+                var names = new Stack<string>();
+                VisitMember(node, names);
+                var name = string.Join('.', names);
+                builder.Append(name);
+            }
 
-                return base.VisitBinary(node);
+            private static void VisitMember(MemberExpression node, Stack<string> names)
+            {
+                var name = node.Member.Name;
+                var filterName = node.Member.GetCustomAttribute<IFilter.FilterNameAttribute>();
+                if (filterName != null)
+                {
+                    name = filterName.Name;
+                }
+
+                names.Push(name);
+                if (node.Expression is MemberExpression expression)
+                {
+                    VisitMember(expression, names);
+                }
             }
 
             public override string ToString()

diff --git a/WindivertDotnet/IFilter.cs b/WindivertDotnet/IFilter.cs
@@ -1,4 +1,5 @@
-using System.Net;
+using System;
+using System.Net;
 
 namespace WindivertDotnet
 {
@@ -7,24 +8,33 @@ namespace WindivertDotnet
     /// </summary>
     public interface IFilter
     {
+        [FilterName("outbound")]
         bool Outbound { get; }
 
+        [FilterName("inbound")]
         bool Inbound { get; }
 
+        [FilterName("ip")]
         IIP Ip { get; }
 
-        bool IsTcp { get; }
+        [FilterName("tcp")]
+        bool TcpProtocol { get; }
 
+        [FilterName("tcp")]
         ITcp Tcp { get; }
 
-        bool IsUdp { get; }
+        [FilterName("udp")]
+        bool UdpProtocol { get; }
 
+        [FilterName("udp")]
         IUdp Udp { get; }
 
+        [FilterName("ifIdx")]
         int IfIdx { get; }
 
+        [FilterName("subIfIdx")]
         int SubIfIdx { get; }
- 
+
         public interface IIP
         {
             int Checksum { get; }
@@ -49,7 +59,7 @@ public interface ITransfer
             int SrcPort { get; }
             int DstPort { get; }
         }
-         
+
         public interface ITcp : ITransfer
         {
             int SeqNum { get; }
@@ -62,5 +72,17 @@ public interface IUdp : ITransfer
         {
             int Length { get; }
         }
+
+
+        [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
+        public sealed class FilterNameAttribute : Attribute
+        {
+            public string Name { get; }
+
+            public FilterNameAttribute(string name)
+            {
+                this.Name = name;
+            }
+        }
     }
 }