lib/ber.c

   1 /* Author : Rahul G rahul@smartbridges.com */
   2
   3
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <stdlib.h>
   7
   8 /* This function takes the oid in dot format ( 1.3.6.1.4.410.... ) and encodes
   9  * the oid using ber rules. oid_out should be allocated by the application..
  10  * encode_oid returns the length of the encoded buffer.
  11  */
  12 int encode_oid(char* oid, unsigned char* oid_out)
  13 {
  14         char* ptr;
  15         int count=0,  oct_count=2;
  16         int num_val=0, oct1=0;
  17         char val[32];
  18         int last=0,len=0;
  19
  20         oid_out[0]=0x06 ; /* 00000110 */
  21         while(( (ptr=strchr(oid,'.')) != 0) || last == 0 )
  22         {
  23                 if(ptr != 0)
  24                         len=ptr-oid;
  25                 else
  26                         len=strlen(oid);
  27
  28                 strncpy(val,oid,len);
  29                 val[len]='\0';
  30                 num_val=atoi(val);
  31 /*get the first two sub id's*/
  32                 if(count == 0)
  33                 {
  34                         oct1=40* num_val;
  35                         count++;
  36                         oid=ptr+1;
  37                         continue;
  38                 }
  39                 if(count == 1)
  40                 {
  41                         oct1+=num_val;
  42                         oid_out[oct_count]=oct1;
  43                         oct_count++;
  44                         oid=ptr+1;
  45                         count++;
  46                         continue;
  47                 }
  48                 else
  49                 {
  50                         int i, loop, j;
  51                         for(i=31;i>= 0; i--)
  52                         {
  53                                 unsigned int mask= (num_val>>(i)) & ~(~0x0000<<1);
  54                                 if(mask)
  55                                 {
  56                                         i++;
  57                                         break;
  58                                 }
  59                         }
  60                         loop=  i/ 7;
  61                         for(j=loop; j>= 0; j--)
  62                         {
  63                                 oid_out[oct_count]= (num_val >> (j*7)) &  ~(~0x0000 << 7);
  64                                 oid_out[oct_count] |= 0x80; /* turn the msb to 1 */
  65                                 oct_count++;
  66                         }
  67                         oid_out[oct_count - 1] &= 0x7f; /* turn the msb back to zero for the last octect */
  68                 }
  69                 if(ptr != 0)
  70                 {
  71                         oid=ptr+1;
  72                 }
  73                 else
  74                 {
  75                         last=1;
  76                 }
  77         }
  78
  79 //Insert the octect length
  80         oid_out[1]=oct_count-2;
  81         return oct_count;
  82
  83 }
  84
  85 /*
  86 int main()
  87 {
  88
  89         unsigned char oid_ut[512];
  90         int k,ret;
  91 //      ret=encode_oid("1.3.6.1.4.1.410.1.1.1.1.0",oid_ut);
  92         ret=encode_oid("1.2.840.113549.1",oid_ut);
  93
  94         for(k=0; k< ret; k++)
  95                 printf("%.2x ",oid_ut[k]);
  96         printf("\n");
  97         return 0;
  98 }
  99
 100 */
 101