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      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 }
    169