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Redirector/IPEventHandler.cpp

@@ -2,9 +2,45 @@
 
 #include "Utils.h"
 
-#include <stdio.h>
+USHORT IPv4Checksum(PBYTE buffer, ULONG64 size)
+{
+	UINT32 sum = 0;
+	for (int i = 0; i < size; i += 2)
+	{
+		sum += (buffer[i] << 8) + buffer[i + 1];
+	}
 
-using namespace std;
+	if ((size % 2) == 1)
+	{
+		sum += buffer[size - 1] << 8;
+	}
+
+	while (sum > 0xffff)
+	{
+		sum = (sum >> 16) + (sum & 0xffff);
+	}
+
+	return ~sum & 0xffff;
+}
+
+USHORT ICMPChecksum(PBYTE buffer, ULONG64 size)
+{
+	UINT32 sum = 0;
+	for (int i = 0; i < size; i += 2)
+	{
+		sum += buffer[i] + (buffer[i + 1] << 8);
+	}
+
+	if ((size % 2) == 1)
+	{
+		sum += buffer[size - 1];
+	}
+
+	sum = (sum >> 16) + (sum & 0xffff);
+	sum += (sum >> 16);
+
+	return ~sum & 0xffff;
+}
 
 void ipSend(const char* buffer, int length, PNF_IP_PACKET_OPTIONS options)
 {