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 xdtoi(int);
  42 static inline int skip_space(FILE *);
  43 static inline int skip_line(FILE *);
  44
  45 /* Hex digit to integer. */
  46 static inline int
  47 xdtoi(int c)
  48 {
  49         if (isdigit(c))
  50                 return c - '0';
  51         else if (islower(c))
  52                 return c - 'a' + 10;
  53         else
  54                 return c - 'A' + 10;
  55 }
  56
  57 static inline int
  58 skip_space(FILE *f)
  59 {
  60         int c;
  61
  62         do {
  63                 c = getc(f);
  64         } while (isspace(c) && c != '\n');
  65
  66         return c;
  67 }
  68
  69 static inline int
  70 skip_line(FILE *f)
  71 {
  72         int c;
  73
  74         do
  75                 c = getc(f);
  76         while (c != '\n' && c != EOF);
  77
  78         return c;
  79 }
  80
  81 struct pcap_etherent *
  82 pcap_next_etherent(FILE *fp)
  83 {
  84         register int c, d, i;
  85         char *bp;
  86         static struct pcap_etherent e;
  87
  88         memset((char *)&e, 0, sizeof(e));
  89         for (;;) {
  90                 /* Find addr */
  91                 c = skip_space(fp);
  92                 if (c == EOF)
  93                         return (NULL);
  94                 if (c == '\n')
  95                         continue;
  96
  97                 /* If this is a comment, or first thing on line
  98                    cannot be Ethernet address, skip the line. */
  99                 if (!isxdigit(c)) {
 100                         c = skip_line(fp);
 101                         if (c == EOF)
 102                                 return (NULL);
 103                         continue;
 104                 }
 105
 106                 /* must be the start of an address */
 107                 for (i = 0; i < 6; i += 1) {
 108                         d = xdtoi(c);
 109                         c = getc(fp);
 110                         if (c == EOF)
 111                                 return (NULL);
 112                         if (isxdigit(c)) {
 113                                 d <<= 4;
 114                                 d |= xdtoi(c);
 115                                 c = getc(fp);
 116                                 if (c == EOF)
 117                                         return (NULL);
 118                         }
 119                         e.addr[i] = d;
 120                         if (c != ':')
 121                                 break;
 122                         c = getc(fp);
 123                         if (c == EOF)
 124                                 return (NULL);
 125                 }
 126
 127                 /* Must be whitespace */
 128                 if (!isspace(c)) {
 129                         c = skip_line(fp);
 130                         if (c == EOF)
 131                                 return (NULL);
 132                         continue;
 133                 }
 134                 c = skip_space(fp);
 135                 if (c == EOF)
 136                         return (NULL);
 137
 138                 /* hit end of line... */
 139                 if (c == '\n')
 140                         continue;
 141
 142                 if (c == '#') {
 143                         c = skip_line(fp);
 144                         if (c == EOF)
 145                                 return (NULL);
 146                         continue;
 147                 }
 148
 149                 /* pick up name */
 150                 bp = e.name;
 151                 /* Use 'd' to prevent buffer overflow. */
 152                 d = sizeof(e.name) - 1;
 153                 do {
 154                         *bp++ = c;
 155                         c = getc(fp);
 156                         if (c == EOF)
 157                                 return (NULL);
 158                 } while (!isspace(c) && --d > 0);
 159                 *bp = '\0';
 160
 161                 /* Eat trailing junk */
 162                 if (c != '\n')
 163                         (void)skip_line(fp);
 164
 165                 return &e;
 166         }
 167 }