TargetGroup.cc

/***************************************************************************
 * 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************************
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 * also a registered trademark of Insecure.Com LLC.  This program is free  *
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 *                                                                         *
 ***************************************************************************/

/* $Id$ */

#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 = ((unsigned long long) (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 = (unsigned long long) (last[0] + 1) *
              (unsigned long long) (last[1] + 1) *
              (unsigned long long) (last[2] + 1) *
              (unsigned long long) (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;
  namedhost = 0;

  if (targets_type != TYPE_NONE)
    Initialize();

  ipsleft = 0;

  resolvedaddrs.clear();

  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 = hostexp;
    s = strchr(hostexp, '/'); /* Find the slash if there is one */
    if (s) {
      char *tail;
      long netmask_long;
      
      *s = '\0';  /* Make sure target_net is terminated before the /## */
      s++;        /* Point s at the netmask */
      if (!isdigit((int) (unsigned char) *s)) {
        error("Illegal netmask value, must be /0 - /32 .  Assuming /32 (one host)");
        netmask = 32;
      } else {
        netmask_long = strtol(s, (char**) &tail, 10);
        if (*tail != '\0' || tail == s || netmask_long < 0 || netmask_long > 32) {
          error("Illegal netmask value, must be /0 - /32 .  Assuming /32 (one host)");
          netmask = 32;
        } else
          netmask = (u32) netmask_long;
      }
    } else
      netmask = 32;
    resolvedname = hostexp;
    for(i=0; *(hostexp + i); i++) 
      if (isupper((int) (unsigned char) *(hostexp +i)) ||
          islower((int) (unsigned char) *(hostexp +i))) {
        namedhost = 1;
        break;
      }
    if (netmask != 32 || namedhost) {
      struct in_addr addr;

      targets_type = IPV4_NETMASK;
      if (!inet_pton(AF_INET, target_net, &(addr))) {
        if ((target = gethostbyname(target_net))) {
          int count=0;

          memcpy(&(addr), target->h_addr_list[0], sizeof(addr));

          while (target->h_addr_list[count]) {
            struct sockaddr_storage ss;
            struct sockaddr_in *sin = (struct sockaddr_in *) &ss;

            sin->sin_family = AF_INET;
            sin->sin_addr = addr;
            resolvedaddrs.push_back(ss);
            count++;
          }

          if (count > 1 && o.verbose > 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;
        }
      } 
      if (netmask) {
        unsigned long longtmp = ntohl(addr.s_addr);
        startaddr.s_addr = longtmp & (unsigned long) (0 - (1<<(32 - netmask)));
        endaddr.s_addr = longtmp | (unsigned long)  ((1<<(32 - netmask)) - 1);
      } else {
        /* The above calculations don't work for a /0 netmask, though at first
         * glance it appears that they would
         */
        startaddr.s_addr = 0;
        endaddr.s_addr = 0xffffffff;
      }
      currentaddr = startaddr;
      if (startaddr.s_addr <= endaddr.s_addr) { 
        ipsleft = ((unsigned long long) (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) (unsigned char) *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.");
        *r++;
      }
      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) == '\0') 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 = (unsigned long long) (last[0] + 1) *
              (unsigned long long) (last[1] + 1) *
              (unsigned long long) (last[2] + 1) *
              (unsigned long long) (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 || result == NULL) {
      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, sin6, sizeof(struct sockaddr_in6));
    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;

  /* The decision to skip a range was based on the address that came immediately
     before what our current array contains now. For example, if we have just
     handed out 0.0.0.0 from the the range 0-5.0.0.0, and we're asked to skip
     the first octet, we want to advance to 1.0.0.0. But 1.0.0.0 is what is in
     the current array right now, because TargetGroup::get_next_host advances
     the array after returning an address. If we didn't step back we would
     erroneously skip ahead to 2.0.0.0. */
  return_last_host();

  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;
  }

  ipsleft -= hosts_skipped;
 
  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.sin6_addr.s6_addr, 16);
    sin6->sin6_scope_id = ip6.sin6_scope_id;
#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;
}

/* Returns true iff the given address is the one that was resolved to create
   this target group; i.e., not one of the addresses derived from it with a
   netmask. */
bool TargetGroup::is_resolved_address(const struct sockaddr_storage *ss)
{
  const struct sockaddr_in *sin, *sin_resolved;
  struct sockaddr_storage resolvedaddr;

  if (targets_type != IPV4_NETMASK || ss->ss_family != AF_INET
      || resolvedaddrs.empty()) {
    return false;
  }
  resolvedaddr = *resolvedaddrs.begin();
  if (resolvedaddr.ss_family != AF_INET)
    return false;

  sin = (struct sockaddr_in *) ss;
  sin_resolved = (struct sockaddr_in *) &resolvedaddr;

  return sin->sin_addr.s_addr == sin_resolved->sin_addr.s_addr;
}

/* Return a string of the name or address that was resolved for this group. */
const char *TargetGroup::get_resolved_name(void)
{
  return resolvedname.c_str();
}

/* Return the list of addresses that the name for this group resolved to, if
   it came from a name resolution. */
const std::list<struct sockaddr_storage> &TargetGroup::get_resolved_addrs(void)
{
  return resolvedaddrs;
}

/* 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);
}