/* Original at http://www.BeidelmanSoftware.com/utils/namedgen.c
 * namedgen.c V1.0 28-April-2008 <keith@BeidelmanSoftware.com>
 *
 * Generate a named include script to add all master and slave zones.
 * Master zones are found by scanning /var/named/master for zone files, 
 * which are named exactly the same as the zone for which they represent.  
 * Reverse PTR zones are found by scanning /var/named/rev for zone files.  
 * These zone files must be named x, x.y, or x.y.z, depending on if thy are 
 * /8, /16, or /24 VLSM addresses.  Slave zones are listed in file ./slaves.  
 * This file has 2 entries per slave zone, the master zone's ip, and the 
 * name of the zone.  There must be a /var/named/slaves and a 
 * /var/named/slaves/rev directory on the server, with write permissions for
 * named, so it can fetch the slave zones off the master named server.
 * named will transfer the files to these directories when it is started
 * (or restarted with /etc/rc.d/init.d/named restart).
 * 
 * Building this Utility:
 * 1. Get Source: wget http://www.beidelmansoftware.com/utils/namedgen.c
 * 2.    Compile: gcc -o namedgen namedgen.c
 *
 * Using this Utility:
 * 1. ./namedgen > namedgen-config
 * 2. Add include "namedgen-config"; to named.conf
 * 3. start or restart named with "/etc/rc.d/init.d/named restart".
 *
 */

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

#define NAMED           "/var/named"              // named root
#define MASTER_PATH	NAMED "/master"		  // master zone directory	
#define REV_PATH        NAMED "/rev"              // master reverse dir
#define SLAVE_PATH      NAMED "/namedgen/slaves"  // slave file

char *master =
  "zone \"%s\"\n"
  "  {\n"
  "  type master;\n"
  "  file \"master/%s\";\n"
  "  };\n"
  "\n";

char *masterrev = 
  "zone \"%s.in-addr.arpa\"\n"
  "  {\n"
  "  type master;\n"
  "  file \"rev/%s\";\n"
  "  };\n"
  "\n";

char *slave = 
  "zone \"%s\"\n"
  "  {\n"
  "  type slave;\n"
  "  masters { %s; };\n"
  "  file \"slave/%s\";\n"
  "  };\n"
  "\n";

char *slaverev = 
  "zone \"%s.in-addr.arpa\"\n"
  "  {\n"
  "  type slave;\n"
  "  masters { %s; };\n"
  "  file \"slave/rev/%s\";\n"
  "  };\n"
  "\n";

int reverse (char *domain, char *rdomain)
{
int ip[4], i, ndots, number;


  ndots = 0;
  for (i = 0; i < 3; i++) ip[i] = 0;
  while (*domain)
    {
    if (!isdigit (*domain)) return 0;
    number = 0;
    while (isdigit (*domain))
      {
      number = number * 10 + (*domain - '0');
      if (number < 0 || number > 255) return 0;
      domain++;
      }
    ip[ndots] = number;
    if (*domain == '\0') break;
    if (*domain == '.' && ndots < 3)
      {
      ndots++;
      domain++;
      }
    else
      return 0;
    }
  *rdomain = '\0';
  while (ndots >= 0)
    {
    rdomain += sprintf (rdomain, "%d", ip[ndots]);
    ndots--;
    if (ndots >= 0) strcpy (rdomain++, ".");
    }
  return 1;
}

main ()
{
char domain[1024], rdomain[1024], auth[20];
DIR *dir;
FILE *f;
struct dirent *de;

  if ((dir = opendir (MASTER_PATH)) != NULL)
    {
    while (de = readdir (dir))
      if (de->d_name[0] != '.')
        printf (master, de->d_name, de->d_name);
    closedir (dir);
    }

  if ((dir = opendir (REV_PATH)) != NULL)
    {
    while (de = readdir (dir))
      if (de->d_name[0] != '.')
        if (reverse (de->d_name, rdomain))
          printf (masterrev, rdomain, de->d_name);
        else
          fprintf (stderr, "Can't reverse arpa: %s\n", de->d_name);
    closedir (dir);
    }

  if ((f = fopen (SLAVE_PATH, "r")) != NULL)
    {
    while (fscanf (f, "%s %s\n", auth, domain) == 2)
      if (reverse (domain, rdomain))
        printf (slaverev, rdomain, auth, domain);
      else
        printf (slave, domain, auth, domain);
    fclose (f);
    }
}