nmap/protocols.cc

/***************************************************************************
 * protocols.cc -- Functions relating to the protocol scan and mapping     *
 * between IPproto Number <-> name.                                        *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1996-2019 Insecure.Com LLC ("The Nmap  *
 * Project"). Nmap is also a registered trademark of the Nmap Project.     *
 * 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 ("GPL"), BUT ONLY WITH ALL OF THE   *
 * CLARIFICATIONS AND EXCEPTIONS DESCRIBED HEREIN.  This guarantees your   *
 * right to use, modify, and redistribute this software under certain      *
 * conditions.  If you wish to embed Nmap technology into proprietary      *
 * software, we sell alternative licenses (contact sales@nmap.com).        *
 * Dozens of software vendors already license Nmap technology such as      *
 * host discovery, port scanning, OS detection, version detection, and     *
 * the Nmap Scripting Engine.                                              *
 *                                                                         *
 * Note that the GPL places important restrictions on "derivative works",  *
 * yet it does not provide a detailed definition of that term.  To avoid   *
 * misunderstandings, we interpret that term as broadly as copyright law   *
 * allows.  For example, we consider an application to constitute a        *
 * derivative work for the purpose of this license if it does any of the   *
 * following with any software or content covered by this license          *
 * ("Covered Software"):                                                   *
 *                                                                         *
 * o Integrates source code from Covered Software.                         *
 *                                                                         *
 * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db   *
 * or nmap-service-probes.                                                 *
 *                                                                         *
 * o Is designed specifically to execute Covered Software and parse the    *
 * results (as opposed to typical shell or execution-menu apps, which will *
 * execute anything you tell them to).                                     *
 *                                                                         *
 * o Includes Covered Software in a proprietary executable installer.  The *
 * installers produced by InstallShield are an example of this.  Including *
 * Nmap with other software in compressed or archival form does not        *
 * trigger this provision, provided appropriate open source decompression  *
 * or de-archiving software is widely available for no charge.  For the    *
 * purposes of this license, an installer is considered to include Covered *
 * Software even if it actually retrieves a copy of Covered Software from  *
 * another source during runtime (such as by downloading it from the       *
 * Internet).                                                              *
 *                                                                         *
 * o Links (statically or dynamically) to a library which does any of the  *
 * above.                                                                  *
 *                                                                         *
 * o Executes a helper program, module, or script to do any of the above.  *
 *                                                                         *
 * This list is not exclusive, but is meant to clarify our interpretation  *
 * of derived works with some common examples.  Other people may interpret *
 * the plain GPL differently, so we consider this a special exception to   *
 * the GPL that we apply to Covered Software.  Works which meet any of     *
 * these conditions must conform to all of the terms of this license,      *
 * particularly including the GPL Section 3 requirements of providing      *
 * source code and allowing free redistribution of the work as a whole.    *
 *                                                                         *
 * As another special exception to the GPL terms, the Nmap Project grants  *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included docs/licenses/OpenSSL.txt file, and distribute   *
 * linked combinations including the two.                                  *
 *                                                                         *
 * The Nmap Project has permission to redistribute Npcap, a packet         *
 * capturing driver and library for the Microsoft Windows platform.        *
 * Npcap is a separate work with it's own license rather than this Nmap    *
 * license.  Since the Npcap license does not permit redistribution        *
 * without special permission, our Nmap Windows binary packages which      *
 * contain Npcap may not be redistributed without special permission.      *
 *                                                                         *
 * Any redistribution of Covered Software, including any derived works,    *
 * must obey and carry forward all of the terms of this license, including *
 * obeying all GPL rules and restrictions.  For example, source code of    *
 * the whole work must be provided and free redistribution must be         *
 * allowed.  All GPL references to "this License", are to be treated as    *
 * including the terms and conditions of this license text as well.        *
 *                                                                         *
 * Because this license imposes special exceptions to the GPL, Covered     *
 * Work may not be combined (even as part of a larger work) with plain GPL *
 * software.  The terms, conditions, and exceptions of this license must   *
 * be included as well.  This license is incompatible with some other open *
 * source licenses as well.  In some cases we can relicense portions of    *
 * Nmap or grant special permissions to use it in other open source        *
 * software.  Please contact fyodor@nmap.org with any such requests.       *
 * Similarly, we don't incorporate incompatible open source software into  *
 * Covered Software without special permission from the copyright holders. *
 *                                                                         *
 * If you have any questions about the licensing restrictions on using     *
 * Nmap in other works, we are happy to help.  As mentioned above, we also *
 * offer an alternative license to integrate Nmap into proprietary         *
 * applications and appliances.  These contracts have been sold to dozens  *
 * of software vendors, and generally include a perpetual license as well  *
 * as providing support and updates.  They also fund the continued         *
 * development of Nmap.  Please email sales@nmap.com for further           *
 * information.                                                            *
 *                                                                         *
 * If you have received a written license agreement or contract for        *
 * Covered Software stating terms other than these, you may choose to use  *
 * and redistribute Covered Software under those terms instead of these.   *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes.          *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to the dev@nmap.org mailing list for possible incorporation into the    *
 * main distribution.  By sending these changes to Fyodor or one of the    *
 * Insecure.Org development mailing lists, or checking them into the Nmap  *
 * source code repository, it is understood (unless you specify            *
 * otherwise) that you are offering the Nmap Project the unlimited,        *
 * non-exclusive right to reuse, modify, and relicense the code.  Nmap     *
 * will always be available Open Source, but this is important because     *
 * the inability to relicense code has caused devastating problems for     *
 * other Free Software projects (such as KDE and NASM).  We also           *
 * occasionally relicense the code to third parties as discussed above.    *
 * If you wish to specify special license conditions of your               *
 * contributions, just say so when you send them.                          *
 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of              *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Nmap      *
 * license file for more details (it's in a COPYING file included with     *
 * Nmap, and also available from https://svn.nmap.org/nmap/COPYING)        *
 *                                                                         *
 ***************************************************************************/

/* $Id$ */

#include "protocols.h"
#include "NmapOps.h"
#include "services.h"
#include "charpool.h"
#include "nmap_error.h"
#include "utils.h"

extern NmapOps o;
static int numipprots = 0;
static struct protocol_list *protocol_table[PROTOCOL_TABLE_SIZE];
static int protocols_initialized = 0;

static int nmap_protocols_init() {
  if (protocols_initialized) return 0;

  char filename[512];
  FILE *fp;
  char protocolname[128];
  unsigned short protno;
  char *p;
  char line[1024];
  int lineno = 0;
  struct protocol_list *current, *previous;
  int res;

  if (nmap_fetchfile(filename, sizeof(filename), "nmap-protocols") != 1) {
    error("Unable to find nmap-protocols!  Resorting to /etc/protocols");
    strcpy(filename, "/etc/protocols");
  }

  fp = fopen(filename, "r");
  if (!fp) {
    fatal("Unable to open %s for reading protocol information", filename);
  }
  /* Record where this data file was found. */
  o.loaded_data_files["nmap-protocols"] = filename;

  memset(protocol_table, 0, sizeof(protocol_table));

  while(fgets(line, sizeof(line), fp)) {
    lineno++;
    p = line;
    while(*p && isspace((int) (unsigned char) *p))
      p++;
    if (*p == '#')
      continue;
    res = sscanf(line, "%127s %hu", protocolname, &protno);
    if (res !=2)
      continue;

    /* Now we make sure our protocols don't have duplicates */
    for(current = protocol_table[protno % PROTOCOL_TABLE_SIZE], previous = NULL;
        current; current = current->next) {
      if (protno == current->protoent->p_proto) {
        if (o.debugging) {
          error("Protocol %d is duplicated in protocols file %s", ntohs(protno), filename);
        }
        break;
      }
      previous = current;
    }
    if (current)
      continue;

    numipprots++;

    current = (struct protocol_list *) cp_alloc(sizeof(struct protocol_list));
    current->protoent = (struct protoent *) cp_alloc(sizeof(struct protoent));
    current->next = NULL;
    if (previous == NULL) {
      protocol_table[protno % PROTOCOL_TABLE_SIZE] = current;
    } else {
      previous->next = current;
    }
    current->protoent->p_name = cp_strdup(protocolname);
    current->protoent->p_proto = protno;
    current->protoent->p_aliases = NULL;
  }
  fclose(fp);
  protocols_initialized = 1;
  return 0;
}


/* Adds protocols whose names match mask to porttbl.
 * Increases the prot_count in ports by the number of protocols added.
 * Returns the number of protocols added.
 */


int addprotocolsfromservmask(char *mask, u8 *porttbl) {
  struct protocol_list *current;
  int bucket, t=0;

  if (!protocols_initialized && nmap_protocols_init() == -1)
    fatal("%s: Couldn't get protocol numbers", __func__);

  for(bucket = 0; bucket < PROTOCOL_TABLE_SIZE; bucket++) {
    for(current = protocol_table[bucket % PROTOCOL_TABLE_SIZE]; current; current = current->next) {
      if (wildtest(mask, current->protoent->p_name)) {
        porttbl[ntohs(current->protoent->p_proto)] |= SCAN_PROTOCOLS;
        t++;
      }
    }
  }

  return t;

}


struct protoent *nmap_getprotbynum(int num) {
  struct protocol_list *current;

  if (nmap_protocols_init() == -1)
    return NULL;

  for(current = protocol_table[num % PROTOCOL_TABLE_SIZE];
      current; current = current->next) {
    if (num == current->protoent->p_proto)
      return current->protoent;
  }

  /* Couldn't find it ... oh well. */
  return NULL;
}