xref: /freebsd/contrib/libpcap/etherent.c (revision a0409676120c1e558d0ade943019934e0f15118d)
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