/*      $NetBSD: etherent.c,v 1.6 2024/09/02 15:33:36 christos Exp $    */

/*
* 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 <sys/cdefs.h>
__RCSID("$NetBSD: etherent.c,v 1.6 2024/09/02 15:33:36 christos Exp $");

#include <config.h>

#include <pcap-types.h>

#include <memory.h>
#include <stdio.h>
#include <string.h>

#include "pcap-int.h"

#include <pcap/namedb.h>

#include "thread-local.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

static inline int skip_space(FILE *);
static inline int skip_line(FILE *);

/* Hex digit to integer. */
static inline u_char
xdtoi(u_char c)
{
       if (c >= '0' && c <= '9')
               return (u_char)(c - '0');
       else if (c >= 'a' && c <= 'f')
               return (u_char)(c - 'a' + 10);
       else
               return (u_char)(c - 'A' + 10);
}

/*
* Skip linear white space (space and tab) and any CRs before LF.
* Stop when we hit a non-white-space character or an end-of-line LF.
*/
static inline int
skip_space(FILE *f)
{
       int c;

       do {
               c = getc(f);
       } while (c == ' ' || c == '\t' || c == '\r');

       return c;
}

static inline 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)
{
       register int c, i;
       u_char d;
       char *bp;
       size_t namesize;
       static thread_local struct pcap_etherent e;

       memset((char *)&e, 0, sizeof(e));
       for (;;) {
               /* Find addr */
               c = skip_space(fp);
               if (c == EOF)
                       return (NULL);
               if (c == '\n')
                       continue;

               /* If this is a comment, or first thing on line
                  cannot be Ethernet address, skip the line. */
               if (!PCAP_ISXDIGIT(c)) {
                       c = skip_line(fp);
                       if (c == EOF)
                               return (NULL);
                       continue;
               }

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

               /* Must be whitespace */
               if (c != ' ' && c != '\t' && c != '\r' && c != '\n') {
                       c = skip_line(fp);
                       if (c == EOF)
                               return (NULL);
                       continue;
               }
               c = skip_space(fp);
               if (c == EOF)
                       return (NULL);

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

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

               /* pick up name */
               bp = e.name;
               /* Use 'namesize' to prevent buffer overflow. */
               namesize = sizeof(e.name) - 1;
               do {
                       *bp++ = (u_char)c;
                       c = getc(fp);
                       if (c == EOF)
                               return (NULL);
               } while (c != ' ' && c != '\t' && c != '\r' && c != '\n'
                   && --namesize != 0);
               *bp = '\0';

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

               return &e;
       }
}