linkaddr.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if defined(LIBC_SCCS) && !defined(lint)
33static char sccsid[] = "@(#)linkaddr.c	8.1 (Berkeley) 6/4/93";
34#endif /* LIBC_SCCS and not lint */
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: stable/11/lib/libc/net/linkaddr.c 330897 2018-03-14 03:19:51Z eadler $");
37
38#include <sys/types.h>
39#include <sys/socket.h>
40#include <net/if.h>
41#include <net/if_dl.h>
42#include <string.h>
43
44/* States*/
45#define NAMING	0
46#define GOTONE	1
47#define GOTTWO	2
48#define RESET	3
49/* Inputs */
50#define	DIGIT	(4*0)
51#define	END	(4*1)
52#define DELIM	(4*2)
53#define LETTER	(4*3)
54
55void
56link_addr(const char *addr, struct sockaddr_dl *sdl)
57{
58	char *cp = sdl->sdl_data;
59	char *cplim = sdl->sdl_len + (char *)sdl;
60	int byte = 0, state = NAMING, new;
61
62	bzero((char *)&sdl->sdl_family, sdl->sdl_len - 1);
63	sdl->sdl_family = AF_LINK;
64	do {
65		state &= ~LETTER;
66		if ((*addr >= '0') && (*addr <= '9')) {
67			new = *addr - '0';
68		} else if ((*addr >= 'a') && (*addr <= 'f')) {
69			new = *addr - 'a' + 10;
70		} else if ((*addr >= 'A') && (*addr <= 'F')) {
71			new = *addr - 'A' + 10;
72		} else if (*addr == 0) {
73			state |= END;
74		} else if (state == NAMING &&
75			   (((*addr >= 'A') && (*addr <= 'Z')) ||
76			   ((*addr >= 'a') && (*addr <= 'z'))))
77			state |= LETTER;
78		else
79			state |= DELIM;
80		addr++;
81		switch (state /* | INPUT */) {
82		case NAMING | DIGIT:
83		case NAMING | LETTER:
84			*cp++ = addr[-1];
85			continue;
86		case NAMING | DELIM:
87			state = RESET;
88			sdl->sdl_nlen = cp - sdl->sdl_data;
89			continue;
90		case GOTTWO | DIGIT:
91			*cp++ = byte;
92			/* FALLTHROUGH */
93		case RESET | DIGIT:
94			state = GOTONE;
95			byte = new;
96			continue;
97		case GOTONE | DIGIT:
98			state = GOTTWO;
99			byte = new + (byte << 4);
100			continue;
101		default: /* | DELIM */
102			state = RESET;
103			*cp++ = byte;
104			byte = 0;
105			continue;
106		case GOTONE | END:
107		case GOTTWO | END:
108			*cp++ = byte;
109			/* FALLTHROUGH */
110		case RESET | END:
111			break;
112		}
113		break;
114	} while (cp < cplim);
115	sdl->sdl_alen = cp - LLADDR(sdl);
116	new = cp - (char *)sdl;
117	if (new > sizeof(*sdl))
118		sdl->sdl_len = new;
119	return;
120}
121
122static const char hexlist[] = "0123456789abcdef";
123
124char *
125link_ntoa(const struct sockaddr_dl *sdl)
126{
127	static char obuf[64];
128	_Static_assert(sizeof(obuf) >= IFNAMSIZ + 20, "obuf is too small");
129	char *out;
130	const u_char *in, *inlim;
131	int namelen, i, rem;
132
133	namelen = (sdl->sdl_nlen <= IFNAMSIZ) ? sdl->sdl_nlen : IFNAMSIZ;
134
135	out = obuf;
136	rem = sizeof(obuf);
137	if (namelen > 0) {
138		bcopy(sdl->sdl_data, out, namelen);
139		out += namelen;
140		rem -= namelen;
141		if (sdl->sdl_alen > 0) {
142			*out++ = ':';
143			rem--;
144		}
145	}
146
147	in = (const u_char *)sdl->sdl_data + sdl->sdl_nlen;
148	inlim = in + sdl->sdl_alen;
149
150	while (in < inlim && rem > 1) {
151		if (in != (const u_char *)sdl->sdl_data + sdl->sdl_nlen) {
152			*out++ = '.';
153			rem--;
154		}
155		i = *in++;
156		if (i > 0xf) {
157			if (rem < 3)
158				break;
159			*out++ = hexlist[i >> 4];
160			*out++ = hexlist[i & 0xf];
161			rem -= 2;
162		} else {
163			if (rem < 2)
164				break;
165			*out++ = hexlist[i];
166			rem--;
167		}
168	}
169	*out = 0;
170	return (obuf);
171}
172