xref: /freebsd/contrib/libpcap/etherent.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
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 }
173