From 203bbbcedf282fa360a1699885b4cc1948e82850 Mon Sep 17 00:00:00 2001
From: Othmar Gsenger <otti@wirdorange.org>
Date: Sun, 27 Jan 2013 23:28:42 +0000
Subject: uid check in eeprom working

git-svn-id: https://svn.spreadspace.org/avr/trunk@80 aa12f405-d877-488e-9caf-2d797e2a1cc7
---
 usb-i2c-sl018/tuer-rfid.c | 53 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 12 deletions(-)

(limited to 'usb-i2c-sl018')

diff --git a/usb-i2c-sl018/tuer-rfid.c b/usb-i2c-sl018/tuer-rfid.c
index 244315c..3d47edd 100644
--- a/usb-i2c-sl018/tuer-rfid.c
+++ b/usb-i2c-sl018/tuer-rfid.c
@@ -46,6 +46,7 @@
 typedef union
 {
   uint64_t uint;
+  uint32_t uint32[2];
   unsigned char byte[8];
 } keyslot_t;
 keyslot_t EEMEM keyslots[EEPROM_SIZE/sizeof(keyslot_t)];
@@ -77,6 +78,19 @@ uint8_t card_status =0;
 
 FILE usb_stream;
 FILE * usb = &usb_stream;
+
+#define KEY_LEN_MAX (sizeof(keyslot_t) - 1)
+
+/* this generates a Fletcher8 checksum  */
+/* code from: http://stackoverflow.com/questions/13491700/8-bit-fletcher-checksum-of-16-byte-data */
+unsigned char generate_csum(unsigned char* data)
+{
+  uint16_t sum1 = 0xf, sum2 = 0xf, len = KEY_LEN_MAX;
+  do { sum2 += ( sum1 += *data++ ); } while (--len);
+  return sum2<<4 | sum1;
+}
+
+
 /*
              LUFA Library
      Copyright (C) Dean Camera, 2012.
@@ -162,18 +176,26 @@ unsigned char sl018_send_buffer(const unsigned char * buffer)
 bool check_card(unsigned char * uid, uint8_t uid_len)
 {
   keyslot_t card;
+  keyslot_t eeprom_ks;
   card.uint=0;
   for (uint8_t pos=0; pos<uid_len; pos++)
-    card.byte[pos]=uid[pos];
-  keyslot_t * ks;
-  for(ks=keyslots;ks<keyslots+EEPROM_SIZE/sizeof(keyslot_t);ks++)
+    card.byte[pos]=uid[uid_len-pos-1];
+  card.byte[KEY_LEN_MAX]=generate_csum(&card.byte[0]);
+  keyslot_t * ks=keyslots;
+  bool valid=0;
+  for(uint8_t ks_num=0;ks_num<(EEPROM_SIZE/sizeof(card));ks_num++)
   {
-    if(card.uint==ks->uint)
+    eeprom_read_block(&eeprom_ks,&ks[ks_num],sizeof(eeprom_ks));
+    if(card.uint==eeprom_ks.uint)
     {
-      fprintf(usb,"Found\n");
-      return 1;
+      valid=1;
+      // break; //this breaks security
     }
   }
+  if (valid)
+  {
+    return 1;
+  } 
   return 0;
 }
 
@@ -230,7 +252,6 @@ bool sl018_send_buffer_check_error(const unsigned char * buffer)
   } else {
     if(twi_message->status)
     {
-      CDC_Device_SendString(&VirtualSerial_CDC_Interface, "SL018 Cmd,Error: ");
       fprintf(usb,"SL018 Cmd,Error: %02X,%02X\n\r",twi_message->command,twi_message->status);
       return 0;
     }
@@ -280,11 +301,19 @@ void card_in_action(void)
   fprintf(usb, "CARD IN: ");
   if(sl018_send_buffer_check_error(SL018CMD_ComSelectCard))
   {
-   for (pos=twi_message->len - 4 ; pos< 255; pos--)
-   {
-     fprintf(usb,"%02X",twi_message->data[pos]);
-   }
-   fprintf(usb, "\n\r");
+    for (pos=twi_message->len - 4 ; pos< 255; pos--)
+    {
+      fprintf(usb,"%02X",twi_message->data[pos]);
+    }
+    fprintf(usb, "\n\r");
+    uint8_t type = twi_message->data[twi_message->len-1-sizeof(twi_message->command)-sizeof(twi_message->status)];
+    if (0<type && type < 7)
+    {
+      if(check_card(&twi_message->data[0],twi_message->len-1-sizeof(twi_message->command)-sizeof(twi_message->status)))
+        fprintf(usb,"open\n\r");
+    } else {
+      fprintf(usb,"Unknown Card Type %02x\n\r",type);
+    }
   }  
 }
 
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