nmap/protocols.cc

/***************************************************************************
 * protocols.cc -- Functions relating to the protocol scan and mapping     *
 * between IPproto Number <-> name.                                        *
 *                                                                         *
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/* $Id$ */

#include "protocols.h"
#include "NmapOps.h"
#include "string_pool.h"
#include "nmap_error.h"
#include "utils.h"

#include <map>

extern NmapOps o;

struct strcmp_comparator {
  bool operator()(const char *a, const char *b) const {
    return strcmp(a, b) < 0;
  }
};

// IP Protocol number is 8 bits wide
// protocol_table[IPPROTO_TCP] == {"tcp", 6}
static struct nprotoent *protocol_table[UCHAR_MAX];
// proto_map["tcp"] = {"tcp", 6}
typedef std::map<const char *, struct nprotoent, strcmp_comparator> ProtoMap;
static ProtoMap proto_map;

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

  char filename[512];
  FILE *fp;
  char protocolname[128];
  unsigned short protno;
  char *p;
  char line[1024];
  int lineno = 0;
  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) {
    pfatal("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 == '#' || *p == '\0')
      continue;
    res = sscanf(line, "%127s %hu", protocolname, &protno);
    if (res !=2 || protno > UCHAR_MAX) {
      error("Parse error in protocols file %s line %d", filename, lineno);
      continue;
    }

    struct nprotoent ent;
    // Using string_pool means we don't have to copy this data; the pointer is unique!
    ent.p_name = string_pool_insert(protocolname);
    ent.p_proto = protno;
    std::pair<ProtoMap::iterator, bool> status = proto_map.insert(std::pair<const char *, struct nprotoent>(ent.p_name, ent));

    /* Now we make sure our protocols don't have duplicates */
    if (!status.second) {
      if (o.debugging > 1) {
        error("Protocol %d (%s) has duplicate number (%d) in protocols file %s", status.first->second.p_proto, ent.p_name, protno, filename);
      }
      continue;
    }

    if (protocol_table[protno]) {
      if (o.debugging > 1) {
        error("Protocol %d (%s) has duplicate name (%s) in protocols file %s", protno, protocol_table[protno]->p_name, ent.p_name, filename);
      }
      continue;
    }

    protocol_table[protno] = &status.first->second;
  }
  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) {
  ProtoMap::const_iterator it;
  int t=0;

  if (nmap_protocols_init() != 0)
    fatal("%s: Couldn't get protocol numbers", __func__);

  // Check for easy ones: plain string match.
  it = proto_map.find(mask);
  if (it != proto_map.end()) {
    // Matched! No need to try wildtest on everything.
    porttbl[it->second.p_proto] |= SCAN_PROTOCOLS;
    return 1;
  }
  // No match? iterate and use wildtest.
  for(it = proto_map.begin(); it != proto_map.end(); it++) {
    if (wildtest(mask, it->second.p_name)) {
      porttbl[it->second.p_proto] |= SCAN_PROTOCOLS;
      t++;
    }
  }

  return t;

}


const struct nprotoent *nmap_getprotbynum(int num) {

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

  assert(num >= 0 && num < UCHAR_MAX);
  return protocol_table[num];
}

const struct nprotoent *nmap_getprotbyname(const char *name) {

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

  ProtoMap::const_iterator it = proto_map.find(name);
  if (it != proto_map.end()) {
    return &it->second;
  }
  return NULL;
}