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 <memory.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31
  32 #include "pcap-int.h"
  33
  34 #include <pcap/namedb.h>
  35
  36 #ifdef HAVE_OS_PROTO_H
  37 #include "os-proto.h"
  38 #endif
  39
  40 static inline int skip_space(FILE *);
  41 static inline int skip_line(FILE *);
  42
  43 /* Hex digit to integer. */
  44 static inline u_char
  45 xdtoi(u_char c)
  46 {
  47         if (c >= '0' && c <= '9')
  48                 return (u_char)(c - '0');
  49         else if (c >= 'a' && c <= 'f')
  50                 return (u_char)(c - 'a' + 10);
  51         else
  52                 return (u_char)(c - 'A' + 10);
  53 }
  54
  55 /*
  56  * Skip linear white space (space and tab) and any CRs before LF.
  57  * Stop when we hit a non-white-space character or an end-of-line LF.
  58  */
  59 static inline int
  60 skip_space(FILE *f)
  61 {
  62         int c;
  63
  64         do {
  65                 c = getc(f);
  66         } while (c == ' ' || c == '\t' || c == '\r');
  67
  68         return c;
  69 }
  70
  71 static inline int
  72 skip_line(FILE *f)
  73 {
  74         int c;
  75
  76         do
  77                 c = getc(f);
  78         while (c != '\n' && c != EOF);
  79
  80         return c;
  81 }
  82
  83 struct pcap_etherent *
  84 pcap_next_etherent(FILE *fp)
  85 {
  86         register int c, i;
  87         u_char d;
  88         char *bp;
  89         size_t namesize;
  90         static struct pcap_etherent e;
  91
  92         memset((char *)&e, 0, sizeof(e));
  93         for (;;) {
  94                 /* Find addr */
  95                 c = skip_space(fp);
  96                 if (c == EOF)
  97                         return (NULL);
  98                 if (c == '\n')
  99                         continue;
 100
 101                 /* If this is a comment, or first thing on line
 102                    cannot be Ethernet address, skip the line. */
 103                 if (!PCAP_ISXDIGIT(c)) {
 104                         c = skip_line(fp);
 105                         if (c == EOF)
 106                                 return (NULL);
 107                         continue;
 108                 }
 109
 110                 /* must be the start of an address */
 111                 for (i = 0; i < 6; i += 1) {
 112                         d = xdtoi((u_char)c);
 113                         c = getc(fp);
 114                         if (c == EOF)
 115                                 return (NULL);
 116                         if (PCAP_ISXDIGIT(c)) {
 117                                 d <<= 4;
 118                                 d |= xdtoi((u_char)c);
 119                                 c = getc(fp);
 120                                 if (c == EOF)
 121                                         return (NULL);
 122                         }
 123                         e.addr[i] = d;
 124                         if (c != ':')
 125                                 break;
 126                         c = getc(fp);
 127                         if (c == EOF)
 128                                 return (NULL);
 129                 }
 130
 131                 /* Must be whitespace */
 132                 if (c != ' ' && c != '\t' && c != '\r' && c != '\n') {
 133                         c = skip_line(fp);
 134                         if (c == EOF)
 135                                 return (NULL);
 136                         continue;
 137                 }
 138                 c = skip_space(fp);
 139                 if (c == EOF)
 140                         return (NULL);
 141
 142                 /* hit end of line... */
 143                 if (c == '\n')
 144                         continue;
 145
 146                 if (c == '#') {
 147                         c = skip_line(fp);
 148                         if (c == EOF)
 149                                 return (NULL);
 150                         continue;
 151                 }
 152
 153                 /* pick up name */
 154                 bp = e.name;
 155                 /* Use 'namesize' to prevent buffer overflow. */
 156                 namesize = sizeof(e.name) - 1;
 157                 do {
 158                         *bp++ = (u_char)c;
 159                         c = getc(fp);
 160                         if (c == EOF)
 161                                 return (NULL);
 162                 } while (c != ' ' && c != '\t' && c != '\r' && c != '\n'
 163                     && --namesize != 0);
 164                 *bp = '\0';
 165
 166                 /* Eat trailing junk */
 167                 if (c != '\n')
 168                         (void)skip_line(fp);
 169
 170                 return &e;
 171         }
 172 }