made PREFIX_PRESERVING work for IPv6

git-svn-id: file:///home/svn/mapi/trunk@877 8d5bb341-7cf1-0310-8cf6-ba355fef3186

src/anonflib/anon_prefix_preserving.c

@@ -18,7 +18,7 @@ UINT8 m_key[16]; //128 bit secret key
 UINT8 m_pad[16]; //128 bit secret pad
 
 int init_prefix(Mode mode,Direction dir,const UINT8 * key,KeyLength keyLen,UINT8 * initVector);
-void prefix_preserving_anonymize_field(unsigned char *raw_addr); 
+void prefix_preserving_anonymize_field(unsigned char *raw_addr, int len); 
 
 
 static UINT8 S[256]=
@@ -1618,9 +1618,51 @@ UINT32 anonymize(const UINT32 orig_addr) {
     return result ^ orig_addr;
 }
 
+void anonymize6(unsigned char *raw_addr) {
+    UINT8 rin_output[16];
+    UINT8 rin_input[16];
+    static const UINT8 mask[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };
+    UINT8 maskbit, addrbyte;
+    int pos;
+    memcpy(rin_input, m_pad, 16);
+
+    // For each prefixes with length from 0 to 127, generate a bit using the Rijndael cipher,
+    // which is used as a pseudorandom function here. The bits generated in every rounds
+    // are combineed into a pseudorandom one-time-pad.
+    //
+    //Padding: The most significant pos bits are taken from orig_addr. The other 128-pos 
+    //bits are taken from m_pad. The variables first4bytes_pad and first4bytes_input are used
+    //to handle the annoying byte order problem.
+
+    //Encryption: The Rijndael cipher is used as pseudorandom function. During each 
+    //round, only the first bit of rin_output is used.
+    blockEncrypt(rin_input, 128, rin_output);	
+    for (pos = 0; pos < 127; pos++) {
+	maskbit = mask[pos % 8];
+	addrbyte = raw_addr[pos / 8];
+	
+	// xor bit "pos" of address with first rin_output bit
+	if (rin_output[0] & 0x80)
+	    raw_addr[pos / 8] ^= maskbit;
+
+	// copy bit "pos" (0 is MSB, 127 is LSB) from original address to rin_input
+	if ((rin_input[pos / 8] & maskbit) != (addrbyte & maskbit))
+	    rin_input[pos / 8] ^= maskbit;
+	
+	//Encryption: The Rijndael cipher is used as pseudorandom function. During each 
+	//round, only the first bit of rin_output is used.
+	blockEncrypt(rin_input, 128, rin_output);	
+    }
+    // xor bit 127 (LSB) of address with first rin_output bit
+    if (rin_output[0] & 0x80)
+	raw_addr[15] ^= 0x01;
+    
+    return;
+}
+
 int inited=0;
 
-void prefix_preserving_anonymize_field(unsigned char *raw_addr) {
+void prefix_preserving_anonymize_field(unsigned char *raw_addr, int len) {
 	unsigned char my_key[32] = 
     {21,34,23,141,51,164,207,128,19,10,91,22,73,144,125,16,
      216,152,143,131,121,121,101,39,98,87,76,45,42,132,34,2};
@@ -1632,6 +1674,12 @@ void prefix_preserving_anonymize_field(unsigned char *raw_addr) {
 		inited=1;
 	}
 
+	if (len == 16) {
+	    anonymize6(raw_addr);
+	    return;
+	}
+
+	/* IPv4, len == 4 */
 	p=raw_addr[0];
 	raw_addr[0]=raw_addr[3];
 	raw_addr[3]=p;

src/anonflib/anonymization.h

@@ -325,7 +325,7 @@ extern void PrintPacket(FILE *fp, mapipacket *p,int datalink);
 extern void gen_table();
 
 extern void pattern_fill_field(unsigned char *field, int len, int pattern_type, void *pattern);
-extern void prefix_preserving_anonymize_field(unsigned char *raw_addr);
+extern void prefix_preserving_anonymize_field(unsigned char *raw_addr, int len);
 extern void random_field(unsigned char *field, int len);
 extern void filename_random_field(unsigned char *p, int len);
 extern void map_distribution(unsigned char *field, short len, int distribution_type, int arg1, int arg2);

src/anonflib/anonymize.c

@@ -875,7 +875,7 @@ void apply_function_to_field(int function,int protocol,int field,unsigned char *
 			//checkSwap(field_pointer,field);	
 			break;
 		case PREFIX_PRESERVING:
-			prefix_preserving_anonymize_field(field_pointer);
+			prefix_preserving_anonymize_field(field_pointer, len);
 			break;
 		case PREFIX_PRESERVING_MAP:
 			hide_addr(field_pointer);