string is not tokenized properly

Question

I am applying one formula over ip address. but it gives me some random output sometimes, which is weired. sometimes it does not tokenize properly, and sometimes it gives 0 value. Ratio of error regenaration is almost 2-5 in a 1000 sample.
calling function = formula(IPADDRESS); which I am calling with hundreds of different IPs per second.

 int formula ( char ip[]){

            char *token = NULL;
            unsigned long value;
            int finalv;
            char ipaddress[16];
            char delims[]=".";        
            int octet=3;
            value = 0;
            FILE *fp;
            fp = fopen(LOGFILE, "a");
            strcpy(ipaddress,ip);
            fprintf(fp, "%s\n",ipaddress);
            token = strtok( ipaddress,delims);

            while( token != NULL ) {
               fprintf(fp,"%d",(atoi(token));
               if ( atoi(token) != 0 ){
                    if(octet ==3)
                            value = value + (255 * 255 * 255 * (atoi(token)));
                    else if(octet ==2)
                            value = value + (255 * 255 * (atoi(token)));
                    else if(octet ==1)
                            value = value + (255 * (atoi(token)));
                    else if(octet ==0)
                            value = value + (atoi(token));
               }
                    octet--;
               token = strtok( NULL,delims);
            }

            finalv = value % 9999;

            fprintf(fp, " -- %d \n",(int)finalv);
            if(fp)
                    fclose(fp);
            return (int)v;
    }

OUTPUTFILE : (I have Given only false outputs)

172.17.82.255
 172  0  1  -- 1983
--
172.254.254.254
 172  0  0  0  -- 1728
--
172.255.255.225
 172  0  -- 1728
--
172.255.255.255
 172  21  0  1  -- 7390
--
172.255.84.255
 172  0  8  -- 3768

Answer 1

Instead of looping over strtok(), the

int a=0, b=0, c=0, d=0 ;
int value ;
sscanf( ip, "%d.%d.%d.%d", &a, &b, &c, &d );
value = ( ( a * 255 + b ) * 255 + c ) * 255 + d ;
finalv = value % 9999

should, I think, give you the same answers. (Although as pointed out in the comments, the 255s may be meant to be 256).