The Tcpdump Group git mirrors - libpcap/blob - etherent.c

   1 /*
   2  * Copyright (c) 1990, 1993, 1994, 1995, 1996
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <pcap-types.h>
  27
  28 #include <ctype.h>
  29 #include <memory.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32
  33 #include "pcap-int.h"
  34
  35 #include <pcap/namedb.h>
  36
  37 #ifdef HAVE_OS_PROTO_H
  38 #include "os-proto.h"
  39 #endif
  40
  41 static inline int skip_space(FILE *);
  42 static inline int skip_line(FILE *);
  43
  44 /* Hex digit to integer. */
  45 static inline u_char
  46 xdtoi(u_char c)
  47 {
  48         if (isdigit(c))
  49                 return (u_char)(c - '0');
  50         else if (islower(c))
  51                 return (u_char)(c - 'a' + 10);
  52         else
  53                 return (u_char)(c - 'A' + 10);
  54 }
  55
  56 static inline int
  57 skip_space(FILE *f)
  58 {
  59         int c;
  60
  61         do {
  62                 c = getc(f);
  63         } while (isspace(c) && c != '\n');
  64
  65         return c;
  66 }
  67
  68 static inline int
  69 skip_line(FILE *f)
  70 {
  71         int c;
  72
  73         do
  74                 c = getc(f);
  75         while (c != '\n' && c != EOF);
  76
  77         return c;
  78 }
  79
  80 struct pcap_etherent *
  81 pcap_next_etherent(FILE *fp)
  82 {
  83         register int c, i;
  84         u_char d;
  85         char *bp;
  86         size_t namesize;
  87         static struct pcap_etherent e;
  88
  89         memset((char *)&e, 0, sizeof(e));
  90         for (;;) {
  91                 /* Find addr */
  92                 c = skip_space(fp);
  93                 if (c == EOF)
  94                         return (NULL);
  95                 if (c == '\n')
  96                         continue;
  97
  98                 /* If this is a comment, or first thing on line
  99                    cannot be Ethernet address, skip the line. */
 100                 if (!isxdigit(c)) {
 101                         c = skip_line(fp);
 102                         if (c == EOF)
 103                                 return (NULL);
 104                         continue;
 105                 }
 106
 107                 /* must be the start of an address */
 108                 for (i = 0; i < 6; i += 1) {
 109                         d = xdtoi((u_char)c);
 110                         c = getc(fp);
 111                         if (c == EOF)
 112                                 return (NULL);
 113                         if (isxdigit(c)) {
 114                                 d <<= 4;
 115                                 d |= xdtoi((u_char)c);
 116                                 c = getc(fp);
 117                                 if (c == EOF)
 118                                         return (NULL);
 119                         }
 120                         e.addr[i] = d;
 121                         if (c != ':')
 122                                 break;
 123                         c = getc(fp);
 124                         if (c == EOF)
 125                                 return (NULL);
 126                 }
 127
 128                 /* Must be whitespace */
 129                 if (!isspace(c)) {
 130                         c = skip_line(fp);
 131                         if (c == EOF)
 132                                 return (NULL);
 133                         continue;
 134                 }
 135                 c = skip_space(fp);
 136                 if (c == EOF)
 137                         return (NULL);
 138
 139                 /* hit end of line... */
 140                 if (c == '\n')
 141                         continue;
 142
 143                 if (c == '#') {
 144                         c = skip_line(fp);
 145                         if (c == EOF)
 146                                 return (NULL);
 147                         continue;
 148                 }
 149
 150                 /* pick up name */
 151                 bp = e.name;
 152                 /* Use 'namesize' to prevent buffer overflow. */
 153                 namesize = sizeof(e.name) - 1;
 154                 do {
 155                         *bp++ = (u_char)c;
 156                         c = getc(fp);
 157                         if (c == EOF)
 158                                 return (NULL);
 159                 } while (!isspace(c) && --namesize != 0);
 160                 *bp = '\0';
 161
 162                 /* Eat trailing junk */
 163                 if (c != '\n')
 164                         (void)skip_line(fp);
 165
 166                 return &e;
 167         }
 168 }