etherent.c

This directory contains source code for tcpdump, a tool for network monitoring and data acquisition

/* 
 * Copyright (c) 1990, 1993, 1994, 1995, 1996
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <ctype.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <net/bpf.h>
#include <pc-name.h>

/*
 * Hex digit to integer.
 */
static int xdtoi (int c)
{
  if (isdigit (c))
    return c - '0';
  if (islower (c))
    return c - 'a' + 10;
  return (c - 'A' + 10);
}

static int skip_space (FILE * f)
{
  int c;

  do
  {
    c = getc (f);
  }
  while (isspace (c) && c != '\n');

  return (c);
}

static int skip_line (FILE * f)
{
  int c;

  do
  {
    c = getc (f);
  }
  while (c != '\n' && c != EOF);

  return (c);
}

struct pcap_etherent *pcap_next_etherent (FILE *fp)
{
  static struct pcap_etherent e;
  int    c, d, i;
  char  *bp;

  memset (&e, 0, sizeof(e));
  do
  {
    /* Find addr */
    c = skip_space (fp);
    if (c == '\n')
       continue;

    /* If this is a comment, or first thing on line
     * cannot be ethernet address, skip the line
     */
    if (!isxdigit (c))
    {
      c = skip_line (fp);
      continue;
    }

    /* must be the start of an address
     */
    for (i = 0; i < 6; i += 1)
    {
      d = xdtoi (c);
      c = getc (fp);
      if (isxdigit (c))
      {
        d <<= 4;
        d |= xdtoi (c);
        c = getc (fp);
      }
      e.addr[i] = d;
      if (c != ':')
        break;
      c = getc (fp);
    }
    if (c == EOF)
      break;

    /* Must be whitespace
     */
    if (!isspace (c))
    {
      c = skip_line(fp);
      continue;
    }
    c = skip_space (fp);

    /* hit end of line... */
    if (c == '\n')
       continue;

    if (c == '#')
    {
      c = skip_line (fp);
      continue;
    }

    /* pick up name */
    bp = e.name;

    /* Use 'd' to prevent buffer overflow. */
    d = sizeof(e.name) - 1;
    do
    {
      *bp++ = c;
      c = getc (fp);
    }
    while (!isspace (c) && c != EOF && --d > 0);
    *bp = '\0';

    /* Eat trailing junk */
    if (c != '\n')
      skip_line (fp);

    return (&e);
  }
  while (c != EOF);

  return (NULL);
}