/*
 * Copyright (c) 2001 - s23a <s23a@mail.ru>
 *
 * [ resolver.c ]
 * 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <fcntl.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>


#define MAX_FILE  25
#define MAX_PATTERN  40
#define LOG_FILE  "pattern"
#define FORMAT_ADDR  "%s"

#define VERSION "0.9"
#define TITLE  "Resolver v"VERSION"  by s23a <s23a@mail.ru>"


char address[35];  /* IP address */

int usage(const char*);
int check_addr(int *);
int extract_addr(int *);
int search_pattern(char *, char*);


int
main(argc, argv)
  int argc;
  char *argv[];
{
  struct hostent *host, *gethostbyaddr();
  char oval[4], *file = NULL, *pattern = NULL, **ptr;
  int final[8], opts, lflag, sflag, aflag, s;
  register int acount, bcount, ccount, a_single, b_single, c_single, d_single;
  FILE *fildes = stdout, *sfile;

  a_single = b_single = c_single = d_single = 0;
  acount = bcount = ccount = 0;
  lflag = sflag = aflag = 0;
  
  while ((opts = getopt(argc, argv, "hf:s:a")) != EOF) {
    switch (opts) {
      case 'f':
        if (strlen(optarg) > MAX_FILE) {
          printf("logfile too long.\n");
          exit(-1);
        }
        file = optarg;
        ++lflag;
        break;
      case 's':
        if (strlen(optarg) > MAX_PATTERN) {
          printf("pattern too long.\n");
          exit(-1);
        }
        pattern = optarg;
        ++sflag;
        break;
      case 'a':
        ++aflag;
        break;
      case 'h':
      default:
        usage(argv[0]);
        break;
    }
  }

  if (argc == 1) 
    usage(argv[0]);

  argc -= optind;
        argv += optind;

  if (argc != 1)
    usage(argv[0]);

  sscanf(*argv, FORMAT_ADDR, address);
  
  extract_addr(final);

  check_addr(final);

  if (lflag) {
    if ((fildes = fopen(file, "a")) != 0) {
      if ((s = open("/dev/tty", O_RDWR)) != -1) {
        ioctl(s, TIOCNOTTY, (char*) NULL);
        close(s);
      }
    }
    else {
      perror("open()");
      exit(-1);
    }
  }

  if (sflag)
    if ((sfile = fopen(LOG_FILE, "a")) == 0) {
      perror("open()");
      exit(-1);
    }

  if(!final[1])
    ++a_single;
  if(!final[3])
    ++b_single;
  if(!final[5])
    ++c_single;
  if(!final[7])
    ++d_single;

  if(a_single)
    goto A_Sing;  

  while (final[0] < final[1]) {
    final[0]+=1;

A_Sing:      
    fprintf((lflag)? fildes: stdout, " |--[A]=[**] %d-(%d)...[**]\n", final[0], final[1]);
    fprintf((lflag)? fildes: stdout, " |   |\n");

    acount=final[2];
    if(b_single)    
                  goto B_Sing;

    while (final[2] < final[3]) {
      final[2]+=1;

B_Sing:      
      fprintf((lflag)? fildes: stdout ," |   |--[B]: %d.%d-(%d)...\n", final[0], final[2], final[3]);  
      fprintf((lflag)? fildes: stdout, " |   |   |\n");
    
      bcount=final[4];
            if(c_single) 
                           goto C_Sing;

      while (final[4] < final[5]) {
        final[4]+=1;

C_Sing:      
        fprintf((lflag)? fildes: stdout," |   |   |--[C]: %d.%d.%d-(%d)...\n", final[0], final[2], final[4], final[5]);

        ccount=final[6];
        if (d_single)
          goto D_Sing;
      
    while (final[6] < final[7]) {
      final[6]+=1;

D_Sing:          
      oval[0]=(unsigned char) final[0];
      oval[1]=(unsigned char) final[2];
      oval[2]=(unsigned char) final[4];
      oval[3]=(unsigned char) final[6];

      if((host = gethostbyaddr(oval, 4, AF_INET)) != NULL) {
        if (sflag) {
          if(search_pattern(pattern, host->h_name)) {
            fprintf(sfile, "%d.%d.%d.%d => %s\n", final[0], final[2], 
                  final[4], final[6], host->h_name);
            fflush(sfile);
          }
        }

                     fprintf(((lflag)?fildes:stdout), " |   |   |   |-- %d.%d.%d.%d => %s\n", 
          final[0], final[2], final[4], final[6], host->h_name);
  
        if (aflag) {
          ptr = host->h_aliases;
          while (*ptr != NULL) {
            fprintf(((lflag)?fildes:stdout)," |   |   |   |   + %d.%d.%d.%d => %s [alias]\n", final[0], final[2], final[4], final[6], *ptr);
            ++ptr;
            if (*ptr == NULL)
              fprintf(((lflag)?fildes: stdout), " |   |   |   |\n");
          }
        }
                                fflush(fildes);
      }
        }
        final[6]=ccount;
                  fprintf(((lflag)?fildes: stdout), " |   |   |\n");
      }
      final[4]=bcount;
              fprintf(((lflag)?fildes: stdout), " |   |\n");
    }
    final[2]=acount;
            fprintf(((lflag)?fildes: stdout), " |\n");
  }

  return (0);
}


int
search_pattern(s1, s2)
  char *s1;
  char *s2;
{
  register int i, j;
  int x, y, count, yes;

  i = j = x = y = count = 0;

  if(strlen(s1) > strlen(s2)) {
    printf("warning: pattern > name\n");
    exit(-1);
  }

  x = ((strlen(s2) / strlen(s1)) -1);
  y = strlen(s2) % strlen(s1);

  for (i=0; i<(strlen(s1) * x + 1 + y); i++, s2++) {
    yes=1;
    for (j=0; j<(strlen(s1)); j++)
      if (*(s1 + j) != *(s2 + j))
        yes=0;
    if (yes)
      ++count;
  }

  return (count);
}


int
extract_addr(fin)
  int *fin;
{
  char *p=NULL, a[4][8], *pa=NULL;
  register int i, j, num=0;
  
  pa = (char*)a;
  bzero((char*)a, 32);               

        for(i=0; i<8; i++)
                *(fin+i)=0;

        for (i=0, (p = strtok(address, ".")); p; (p = strtok(NULL, ".")), ++i) {
    if (i == 4) {
      printf("error: format address incorrect.\n");
      exit(-1);
    }
    strncpy((pa+(i*8)+0), p, 7);
    *(pa+(i*8)+8)='\0';
  }
                                    
        p=NULL;                 

        for (j=0; j<4; j++) {
                for (i=0, (p = strtok((pa+(j*8)+0), "-")); p; (p = strtok(NULL,"-")), i++, num++) {
       if((num == 1) || (num == 3) || (num == 5)) {
                                if(i==0) {
                                        *(fin+num)=0;
                                        *(fin+(num+1))=atoi(p);
                                        ++num;          
                                }       
                                else    
                                        *(fin+num)=atoi(p);
                        }               
                        else            
                                *(fin+num)=atoi(p);
                }               
        }       
          
        return (0);
}


int
check_addr(fin)
  int *fin;
{
  register int i;

  for (i=0; i<8; i++)
    if(*(fin+i)<0 || *(fin+i)>255) {
      (void)printf("error: addres format incorrect\n");
      exit(-1);
    }
    
  return (0);
}


int
usage(progname)
  const char *progname;
{
  (void)printf("\n%s\n", TITLE);
  (void)printf("\nusage: %s [options] ip
   -f <file>  - output to a logfile
   -s <pattern> - search pattern and output to a logfile
   -a     - show hostname aliases\n", progname);
  exit(1);
}