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range.c

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "range.h"
#include <string.h>
#include <stdlib.h>
#include "errors.h"

#ifndef INADDR_NONE
# define INADDR_NONE (in_addr_t)-1
#endif

extern int quiet;

/* is_ip checks if supplied string is an ip address in dotted-decimal
   notation, and fills both members of range structure with its numerical value
   (host byte order)/ Returns 1 on success, 0 on failure */
int is_ip(char* string, struct ip_range* range) {
      unsigned long addr;

      addr = inet_addr(string);
      if(addr != INADDR_NONE) {
            range->start_ip = ntohl(addr);
            range->end_ip     = ntohl(addr);
            return 1;
      } else return 0;
}; 

/* is_range1 checks if supplied string is an IP address range in
   form xxx.xxx.xxx.xxx/xx (as in 192.168.1.2/24) and fills
   range structure with start and end ip addresses of the interval.
   Returns 1 on success, 0 on failure */
int is_range1(char* string, struct ip_range* range) {
      char* separator;
      unsigned long mask;
      char* ip;

      if((ip = (char *)malloc(strlen(string)+1))==NULL) 
            err_die("Malloc failed", quiet);

      if (strlen(string)>19) return 0;
      if(separator=(char*)strchr(string,'/')) {
            separator++;
            mask=atoi(separator);
            if(mask<=0 || mask>32) return 0;
            strcpy(ip, string);
            ip[abs(string-separator)-1]=0;
            if((range->start_ip=inet_addr(ip)) == INADDR_NONE) return 0;
/*          mask=((1<<mask)-1)<<(sizeof(mask)*8-mask); */
            if (mask == 32)
                  mask = ~0;
            else
                  mask=((1<<mask)-1)<<(sizeof(mask)*8-mask);

            range->start_ip=ntohl(range->start_ip); // We store ips in host byte order
            range->start_ip &= mask;
            range->end_ip = range->start_ip | ( ~ mask);
            free(ip);
            return 1;
      }
      free(ip);
      return 0;
};


/* next_address function writes next ip address in range after prev_addr to
   structure pointed by next_addr. Returns 1 if next ip found and 0 otherwise */ 
int next_address(const struct ip_range* range, const struct in_addr* prev_addr, 
             struct in_addr* next_addr) {
      unsigned long pa; // previous address, host byte order
      
      if(prev_addr) {
            pa = ntohl(prev_addr->s_addr);
            if(pa < range->end_ip) {
                  next_addr->s_addr=htonl(++pa); 
                  return 1;
            } else return 0;
      } else {
            next_addr->s_addr=htonl(range->start_ip);
            return 1;
      };
};
      
/* is_range2 checks if supplied string is an IP address range in
   form xxx.xxx.xxx.xxx-xxx (as in 192.168.1.2-15) and fills
   range structure with start and end ip addresses of the interval.
   Returns 1 on success, 0 on failure */
int is_range2(char* string, struct ip_range* range) {
      unsigned long last_octet; /*last octet of last ip in range*/
      char* separator;
      unsigned long addr;
      char* ip;

      if((ip = (char *)malloc(strlen(string)+1))==NULL) 
            err_die("Malloc failed", quiet);
      strcpy(ip,string);

      if(separator = (char*)strchr(ip,'-')) {
            *separator=0;
            separator++;
            last_octet = atoi(separator);
            if(last_octet<0 || last_octet > 255) {
                  free(ip);
                  return 0;
            };
            addr = inet_addr(ip);
            if(addr == INADDR_NONE) {
                  free(ip);
                  return 0;
            };
            range->start_ip = ntohl(addr);
            range->end_ip = (range->start_ip & 0xffffff00) | last_octet;
            if (range->end_ip < range->start_ip) { 
                  free(ip);
                  return 0;
            };
            free(ip);
            return 1;
      }
      free(ip);
      return 0;
};

int print_range(const struct ip_range* range) {
      struct in_addr *addr;
      
      if((addr = (struct in_addr*)malloc(sizeof(struct in_addr)))==NULL) 
            err_die("Malloc failed", quiet);
      
      next_address(range, 0, addr);
      printf("%s\n",inet_ntoa(*addr));
      
      while(next_address(range, addr, addr)) {
              printf("%s\n",inet_ntoa(*addr));
      };
      free(addr);
};

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