add FragmentFlag

xljiulang · Oct 28, 2022 · 0c6ab3c · 0c6ab3c
1 parent e1b3b25
commit 0c6ab3c
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Showing 3 changed files with 78 additions and 4 deletions.
diff --git a/WindivertDotnet.Test/IPHeaderTest.cs b/WindivertDotnet.Test/IPHeaderTest.cs
@@ -19,7 +19,7 @@ public unsafe void IPV4ReadTest()
                 Assert.Equal(packet.TimeToLive, header.TTL);
                 Assert.Equal((byte)packet.Protocol, (byte)header.Protocol);
                 Assert.Equal(packet.SourceAddress, header.SrcAddr);
-                Assert.Equal(packet.DestinationAddress, header.DstAddr);                
+                Assert.Equal(packet.DestinationAddress, header.DstAddr);
             }
         }
 
@@ -36,12 +36,13 @@ public unsafe void IPV4WriteTest()
                 DstAddr = dstAddr,
                 SrcAddr = srcAddr,
                 TOS = 3,
-                FragOff0 = 4,
                 HdrLength = 5,
                 Id = 6,
                 Length = 7,
                 Protocol = ProtocolType.Ggp,
-                TTL = 8
+                TTL = 8,
+                FragmentFlags = FragmentFlag.MoreFragments,
+                FragmentOffset = 9,
             };
 
 
@@ -51,13 +52,15 @@ public unsafe void IPV4WriteTest()
             Assert.Equal(dstAddr, header.DstAddr);
             Assert.Equal(srcAddr, header.SrcAddr);
             Assert.Equal(3, header.TOS);
-            Assert.Equal(4, header.FragOff0);
             Assert.Equal(5, header.HdrLength);
             Assert.Equal(6, header.Id);
 
             Assert.Equal(7, header.Length);
             Assert.Equal(ProtocolType.Ggp, header.Protocol);
             Assert.Equal(8, header.TTL);
+
+            Assert.Equal(FragmentFlag.MoreFragments, header.FragmentFlags);
+            Assert.Equal(9, header.FragmentOffset);
         }
 
         [Fact]

diff --git a/WindivertDotnet/FragmentFlag.cs b/WindivertDotnet/FragmentFlag.cs
@@ -0,0 +1,26 @@
+using System;
+
+namespace WindivertDotnet
+{
+    /// <summary>
+    /// IPv4标记位
+    /// </summary>
+    [Flags]
+    public enum FragmentFlag : ushort
+    { 
+        /// <summary>
+        /// 有分片
+        /// </summary>
+        MoreFragments = 0x1,
+
+        /// <summary>
+        /// 无分片
+        /// </summary>
+        DontFragment = 0x02,
+
+        /// <summary>
+        /// 保护
+        /// </summary>
+        Reserved = 0x04,
+    }
+}
diff --git a/WindivertDotnet/IPV4Header.cs b/WindivertDotnet/IPV4Header.cs
@@ -80,6 +80,51 @@ public ushort FragOff0
             set => fragOff0 = BinaryPrimitives.ReverseEndianness(value);
         }
 
+        /// <summary>
+        /// 标记位
+        /// </summary>
+        public FragmentFlag FragmentFlags
+        {
+            get => (FragmentFlag)MoveRight(fragOff0, 13);
+            set => fragOff0 = (ushort)(MoveLeft((ushort)value, 13) | MoveLeftRight(fragOff0, 3));
+        }
+
+        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+        private ushort FragmentOffsetRaw
+        {
+            get => MoveLeftRight(fragOff0, 3);
+            set => fragOff0 = (ushort)(MoveRightLeft(fragOff0, 13) | MoveLeftRight(value, 3));
+        }
+
+        /// <summary>
+        /// 分片偏移量13位
+        /// </summary>
+        public ushort FragmentOffset
+        {
+            get => BinaryPrimitives.ReverseEndianness(this.FragmentOffsetRaw);
+            set => this.FragmentOffsetRaw = BinaryPrimitives.ReverseEndianness(value);
+        }
+
+        private static ushort MoveLeft(ushort value, byte count)
+        {
+            return (ushort)(value << count);
+        }
+
+        private static ushort MoveRight(ushort value, byte count)
+        {
+            return (ushort)(value >> count);
+        }
+
+        private static ushort MoveLeftRight(ushort value, byte count)
+        {
+            return MoveRight(MoveLeft(value, count), count);
+        }
+
+        private static ushort MoveRightLeft(ushort value, byte count)
+        {
+            return MoveLeft(MoveRight(value, count), count);
+        }
+
         /// <summary>
         /// 获取或设置生存时间
         /// </summary>