
/***************************************************************************
 * TargetGroup.cc -- The "TargetGroup" class holds a group of IP           *
 * addresses, such as those from a '/16' or '10.*.*.*' specification.  It  *
 * also has a trivial HostGroupState class which handles a bunch of        *
 * expressions that go into TargetGroup classes.                           *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1996-2006 Insecure.Com LLC. Nmap is    *
 * also a registered trademark of Insecure.Com LLC.  This program is free  *
 * software; you may redistribute and/or modify it under the terms of the  *
 * GNU General Public License as published by the Free Software            *
 * Foundation; Version 2 with the clarifications and exceptions described  *
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 *   not derivative works.)                                                * 
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 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
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 * with Nmap.                                                              *
 *                                                                         *
 ***************************************************************************/

/* $Id: TargetGroup.cc 6237 2007-11-15 23:01:32Z kris $ */

#include "TargetGroup.h"
#include "NmapOps.h"
#include "nmap_error.h"

extern NmapOps o;

TargetGroup::TargetGroup() {
  Initialize();
}

// Bring back (or start with) original state
void TargetGroup::Initialize() {
  targets_type = TYPE_NONE;
  memset(addresses, 0, sizeof(addresses));
  memset(current, 0, sizeof(current));
  memset(last, 0, sizeof(last));
  ipsleft = 0;
}

/* take the object back to the beginning without  (mdmcl)
 * reinitalizing the data structures */  
int  TargetGroup::rewind() {

  /* For netmasks we must set the current address to the
   * starting address and calculate the ips by distance */
  if (targets_type == IPV4_NETMASK) {
      currentaddr = startaddr;
      if (startaddr.s_addr <= endaddr.s_addr) { 
	ipsleft = endaddr.s_addr - startaddr.s_addr + 1;
	return 0; 
      }
      else
        assert(0);
  }
  /* For ranges, we easily set current to zero and calculate
   * the ips by the number of values in the columns */
  else if (targets_type == IPV4_RANGES) {
    memset((char *)current, 0, sizeof(current));
    ipsleft = (last[0] + 1) * (last[1] + 1) *
      (last[2] + 1) * (last[3] + 1);
    return 0;
  }
#if HAVE_IPV6
  /* For IPV6 there is only one address, this function doesn't
   * make much sence for IPv6 does it? */
  else if (targets_type == IPV6_ADDRESS) {
    ipsleft = 1;
    return 0;
  }
#endif 

  /* If we got this far there must be an error, wrong type */
  return -1;
}

 /* Initializes (or reinitializes) the object with a new expression, such
    as 192.168.0.0/16 , 10.1.0-5.1-254 , or fe80::202:e3ff:fe14:1102 .  
    Returns 0 for success */  
int TargetGroup::parse_expr(const char * const target_expr, int af) {

  int i=0,j=0,k=0;
  int start, end;
  char *r,*s, *target_net;
  char *addy[5];
  char *hostexp = strdup(target_expr);
  struct hostent *target;
  unsigned long longtmp;
  int namedhost = 0;

  if (targets_type != TYPE_NONE)
    Initialize();

  ipsleft = 0;

  if (af == AF_INET) {
  
    if (strchr(hostexp, ':'))
      fatal("Invalid host expression: %s -- colons only allowed in IPv6 addresses, and then you need the -6 switch", hostexp);

    /*struct in_addr current_in;*/
    addy[0] = addy[1] = addy[2] = addy[3] = addy[4] = NULL;
    addy[0] = r = hostexp;
    /* First we break the expression up into the four parts of the IP address
       + the optional '/mask' */
    target_net = strtok(hostexp, "/");
    s = strtok(NULL, "");    /* find the end of the token from hostexp */
    netmask  = ( s ) ? atoi(s) : 32;
    if ((int) netmask <= 0 || netmask > 32) {
      error("Illegal netmask value (%d), must be /1 - /32 .  Assuming /32 (one host)", netmask);
      netmask = 32;
    }
    for(i=0; *(hostexp + i); i++) 
      if (isupper((int) *(hostexp +i)) || islower((int) *(hostexp +i))) {
	namedhost = 1;
	break;
      }
    if (netmask != 32 || namedhost) {
      targets_type = IPV4_NETMASK;
      if (!inet_pton(AF_INET, target_net, &(startaddr))) {
	if ((target = gethostbyname(target_net))) {
          int count=0;

	  memcpy(&(startaddr), target->h_addr_list[0], sizeof(struct in_addr));

          while (target->h_addr_list[count]) count++;

          if (count > 1)
             error("Warning: Hostname %s resolves to %d IPs. Using %s.", target_net, count, inet_ntoa(*((struct in_addr *)target->h_addr_list[0])));
	} else {
	  error("Failed to resolve given hostname/IP: %s.  Note that you can't use '/mask' AND '1-4,7,100-' style IP ranges", target_net);
	  free(hostexp);
	  return 1;
	}
      } 
      longtmp = ntohl(startaddr.s_addr);
      startaddr.s_addr = longtmp & (unsigned long) (0 - (1<<(32 - netmask)));
      endaddr.s_addr = longtmp | (unsigned long)  ((1<<(32 - netmask)) - 1);
      currentaddr = startaddr;
      if (startaddr.s_addr <= endaddr.s_addr) { 
	ipsleft = endaddr.s_addr - startaddr.s_addr + 1;
	free(hostexp); 
	return 0; 
      }
      fprintf(stderr, "Host specification invalid");
      free(hostexp);
      return 1;
    }
    else {
      targets_type = IPV4_RANGES;
      i=0;

      while(*++r) {
	if (*r == '.' && ++i < 4) {
	  *r = '\0';
	  addy[i] = r + 1;
	}
	else if (*r != '*' && *r != ',' && *r != '-' && !isdigit((int)*r)) 
	  fatal("Invalid character in  host specification.  Note in particular that square brackets [] are no longer allowed.  They were redundant and can simply be removed.");
      }
      if (i != 3) fatal("Invalid target host specification: %s", target_expr);
      
      for(i=0; i < 4; i++) {
	j=0;
	do {
	  s = strchr(addy[i],',');
	  if (s) *s = '\0';
	  if (*addy[i] == '*') { start = 0; end = 255; } 
	  else if (*addy[i] == '-') {
	    start = 0;
	    if (!(addy[i] + 1)) end = 255;
	    else end = atoi(addy[i]+ 1);
	  }
	  else {
	    start = end = atoi(addy[i]);
	    if ((r = strchr(addy[i],'-')) && *(r+1) ) end = atoi(r + 1);
	    else if (r && !*(r+1)) end = 255;
	  }
	  /*	  if (o.debugging > 2)
		  log_write(LOG_STDOUT, "The first host is %d, and the last one is %d\n", start, end); */
	  if (start < 0 || start > end || start > 255 || end > 255)
	    fatal("Your host specifications are illegal!");
	  if (j + (end - start) > 255) 
	    fatal("Your host specifications are illegal!");
	  for(k=start; k <= end; k++)
	    addresses[i][j++] = k;
	  last[i] = j-1;
	  if (s) addy[i] = s + 1;
	} while (s);
      }
    }
  memset((char *)current, 0, sizeof(current));
  ipsleft = (last[0] + 1) * (last[1] + 1) *
    (last[2] + 1) * (last[3] + 1);
  }
  else {
#if HAVE_IPV6
    int rc = 0;
    assert(af == AF_INET6);
    if (strchr(hostexp, '/')) {
      fatal("Invalid host expression: %s -- slash not allowed.  IPv6 addresses can currently only be specified individually", hostexp);
    }
    targets_type = IPV6_ADDRESS;
    struct addrinfo hints;
    struct addrinfo *result = NULL;
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = PF_INET6;
    rc = getaddrinfo(hostexp, NULL, &hints, &result);
    if (rc != 0) {
      error("Failed to resolve given IPv6 hostname/IP: %s.  Note that you can't use '/mask' or '[1-4,7,100-]' style ranges for IPv6.  Error code %d: %s", hostexp, rc, gai_strerror(rc));
      free(hostexp);
      if (result) freeaddrinfo(result);
      return 1;
    }
    assert(result->ai_addrlen == sizeof(struct sockaddr_in6));
    struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) result->ai_addr;
    memcpy(ip6.s6_addr, sin6->sin6_addr.s6_addr, 16);
    ipsleft = 1;
    freeaddrinfo(result);
#else // HAVE_IPV6
    fatal("IPv6 not supported on your platform");
#endif // HAVE_IPV6
  }

  free(hostexp);
  return 0;
}

/* For ranges, skip all hosts in an octet,                  (mdmcl)
 * get_next_host should be used for skipping the last octet :-) 
 * returns: number of hosts skipped */
int TargetGroup::skip_range(_octet_nums octet) {
  unsigned long hosts_skipped = 0, /* number of hosts skipped */
      oct = 0;           /* octect number */
      int i = 0;                 /* simple lcv */

  /* This function is only supported for RANGES! */
  if (targets_type != IPV4_RANGES)
    return -1;

  switch (octet) {
    case FIRST_OCTET:
      oct = 0;
      hosts_skipped = (last[1] + 1) * (last[2] + 1) * (last[3] + 1);
      break;
    case SECOND_OCTET:
      oct = 1;
      hosts_skipped = (last[2] + 1) * (last[3] + 1);
      break;
    case THIRD_OCTET:
      oct = 2;
      hosts_skipped = (last[3] + 1);
      break;
    default:  /* Hmm, how'd you do that */
      return -1;
  }

  /* catch if we try to take more than are left */
  assert(ipsleft + 1>= hosts_skipped);

  /* increment the next octect that we can above us */
  for (i = oct; i >= 0; i--) {
    if (current[i] < last[i]) {
      current[i]++;
      break;
    }
    else
      current[i] = 0;
  }

  /* reset all the ones below us to zero */
  for (i = oct+1; i <= 3; i++) {
    current[i] = 0;
  }

  /* we actually don't skip the current, it was accounted for 
   * by get_next_host */
  ipsleft -= hosts_skipped - 1;
 
  return hosts_skipped;
}

 /* Grab the next host from this expression (if any) and updates its internal
    state to reflect that the IP was given out.  Returns 0 and
    fills in ss if successful.  ss must point to a pre-allocated
    sockaddr_storage structure */
int TargetGroup::get_next_host(struct sockaddr_storage *ss, size_t *sslen) {

  int octet;
  struct sockaddr_in *sin = (struct sockaddr_in *) ss;
  struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) ss;
  startover: /* to handle nmap --resume where I have already
		scanned many of the IPs */  
  assert(ss);
  assert(sslen);


  if (ipsleft == 0)
    return -1;
  
  if (targets_type == IPV4_NETMASK) {
    memset(sin, 0, sizeof(struct sockaddr_in));
    sin->sin_family = AF_INET;
    *sslen = sizeof(struct sockaddr_in);
#if HAVE_SOCKADDR_SA_LEN
    sin->sin_len = *sslen;
#endif
    
    if (currentaddr.s_addr <= endaddr.s_addr) {
      sin->sin_addr.s_addr = htonl(currentaddr.s_addr++);
    } else {
      error("Bogus target structure passed to %s", __func__);
      ipsleft = 0;
      return -1;
    }
  }
  else if (targets_type == IPV4_RANGES) {
    memset(sin, 0, sizeof(struct sockaddr_in));
    sin->sin_family = AF_INET;
    *sslen = sizeof(struct sockaddr_in);
#if HAVE_SOCKADDR_SA_LEN
    sin->sin_len = *sslen;
#endif
    if (o.debugging > 2) {
      log_write(LOG_STDOUT, "doing %d.%d.%d.%d = %d.%d.%d.%d\n", current[0], current[1], current[2], current[3], addresses[0][current[0]],addresses[1][current[1]],addresses[2][current[2]],addresses[3][current[3]]);
    }
    /* Set the IP to the current value of everything */
    sin->sin_addr.s_addr = htonl(addresses[0][current[0]] << 24 | 
			addresses[1][current[1]] << 16 |
			addresses[2][current[2]] << 8 | 
			addresses[3][current[3]]);
    
    /* Now we nudge up to the next IP */
    for(octet = 3; octet >= 0; octet--) {
      if (current[octet] < last[octet]) {
	/* OK, this is the column I have room to nudge upwards */
	current[octet]++;
	break;
      } else {
	/* This octet is finished so I reset it to the beginning */
	current[octet] = 0;
      }
    }
    if (octet == -1) {
      /* It didn't find anything to bump up, I must have taken the last IP */
      assert(ipsleft == 1);
      /* So I set current to last with the very final octet up one ... */
      /* Note that this may make current[3] == 256 */
      current[0] = last[0]; current[1] = last[1];
      current[2] = last[2]; current[3] = last[3] + 1;
    } else {
      assert(ipsleft > 1); /* There must be at least one more IP left */
    }
  } else {
    assert(targets_type == IPV6_ADDRESS);
    assert(ipsleft == 1);
#if HAVE_IPV6
    *sslen = sizeof(struct sockaddr_in6);
    memset(sin6, 0, *sslen);
    sin6->sin6_family = AF_INET6;
#ifdef SIN_LEN
    sin6->sin6_len = *sslen;
#endif /* SIN_LEN */
    memcpy(sin6->sin6_addr.s6_addr, ip6.s6_addr, 16);
#else
    fatal("IPV6 not supported on this platform");
#endif // HAVE_IPV6
  }
  ipsleft--;
  
  /* If we are resuming from a previous scan, we have already finished
     scans up to o.resume_ip.  */
  if (sin->sin_family == AF_INET && o.resume_ip.s_addr) {
    if (o.resume_ip.s_addr == sin->sin_addr.s_addr)
      o.resume_ip.s_addr = 0; /* So that we will KEEP the next one */
    goto startover; /* Try again */
  }

  return 0;
}

/* Returns the last given host, so that it will be given again next
     time get_next_host is called.  Obviously, you should only call
     this if you have fetched at least 1 host since parse_expr() was
     called */
int TargetGroup::return_last_host() {
  int octet;

  ipsleft++;
  if (targets_type == IPV4_NETMASK) {
    assert(currentaddr.s_addr > startaddr.s_addr);
    currentaddr.s_addr--;
  } else if (targets_type == IPV4_RANGES) {
    for(octet = 3; octet >= 0; octet--) {
      if (current[octet] > 0) {
	/* OK, this is the column I have room to nudge downwards */
	current[octet]--;
	break;
      } else {
	/* This octet is already at the beginning, so I set it to the end */
	current[octet] = last[octet];
      }
    }
    assert(octet != -1);
  } else {
    assert(targets_type == IPV6_ADDRESS);
    assert(ipsleft == 1);    
  }
  return 0;
}

/* Lookahead is the number of hosts that can be
   checked (such as ping scanned) in advance.  Randomize causes each
   group of up to lookahead hosts to be internally shuffled around.
   The target_expressions array MUST REMAIN VALID IN MEMORY as long as
   this class instance is used -- the array is NOT copied.
 */
HostGroupState::HostGroupState(int lookahead, int rnd, 
			       char *expr[], int numexpr) {
  assert(lookahead > 0);
  hostbatch = (Target **) safe_zalloc(sizeof(Target *) * lookahead);
  max_batch_sz = lookahead;
  current_batch_sz = 0;
  next_batch_no = 0;
  randomize = rnd;
  target_expressions = expr;
  num_expressions = numexpr;
  next_expression = 0;
}

HostGroupState::~HostGroupState() {
  free(hostbatch);
}
