linkaddr.c revision 309692 
1/*-
2 * Copyright (c) 1990, 1993
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 the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)linkaddr.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: releng/11.0/lib/libc/net/linkaddr.c 309692 2016-12-07 23:29:42Z glebius $");
35
36#include <sys/types.h>
37#include <sys/socket.h>
38#include <net/if.h>
39#include <net/if_dl.h>
40#include <string.h>
41
42/* States*/
43#define NAMING	0
44#define GOTONE	1
45#define GOTTWO	2
46#define RESET	3
47/* Inputs */
48#define	DIGIT	(4*0)
49#define	END	(4*1)
50#define DELIM	(4*2)
51#define LETTER	(4*3)
52
53void
54link_addr(const char *addr, struct sockaddr_dl *sdl)
55{
56	char *cp = sdl->sdl_data;
57	char *cplim = sdl->sdl_len + (char *)sdl;
58	int byte = 0, state = NAMING, new;
59
60	bzero((char *)&sdl->sdl_family, sdl->sdl_len - 1);
61	sdl->sdl_family = AF_LINK;
62	do {
63		state &= ~LETTER;
64		if ((*addr >= '0') && (*addr <= '9')) {
65			new = *addr - '0';
66		} else if ((*addr >= 'a') && (*addr <= 'f')) {
67			new = *addr - 'a' + 10;
68		} else if ((*addr >= 'A') && (*addr <= 'F')) {
69			new = *addr - 'A' + 10;
70		} else if (*addr == 0) {
71			state |= END;
72		} else if (state == NAMING &&
73			   (((*addr >= 'A') && (*addr <= 'Z')) ||
74			   ((*addr >= 'a') && (*addr <= 'z'))))
75			state |= LETTER;
76		else
77			state |= DELIM;
78		addr++;
79		switch (state /* | INPUT */) {
80		case NAMING | DIGIT:
81		case NAMING | LETTER:
82			*cp++ = addr[-1];
83			continue;
84		case NAMING | DELIM:
85			state = RESET;
86			sdl->sdl_nlen = cp - sdl->sdl_data;
87			continue;
88		case GOTTWO | DIGIT:
89			*cp++ = byte;
90			/* FALLTHROUGH */
91		case RESET | DIGIT:
92			state = GOTONE;
93			byte = new;
94			continue;
95		case GOTONE | DIGIT:
96			state = GOTTWO;
97			byte = new + (byte << 4);
98			continue;
99		default: /* | DELIM */
100			state = RESET;
101			*cp++ = byte;
102			byte = 0;
103			continue;
104		case GOTONE | END:
105		case GOTTWO | END:
106			*cp++ = byte;
107			/* FALLTHROUGH */
108		case RESET | END:
109			break;
110		}
111		break;
112	} while (cp < cplim);
113	sdl->sdl_alen = cp - LLADDR(sdl);
114	new = cp - (char *)sdl;
115	if (new > sizeof(*sdl))
116		sdl->sdl_len = new;
117	return;
118}
119
120static const char hexlist[] = "0123456789abcdef";
121
122char *
123link_ntoa(const struct sockaddr_dl *sdl)
124{
125	static char obuf[64];
126	_Static_assert(sizeof(obuf) >= IFNAMSIZ + 20, "obuf is too small");
127	char *out;
128	const u_char *in, *inlim;
129	int namelen, i, rem;
130
131	namelen = (sdl->sdl_nlen <= IFNAMSIZ) ? sdl->sdl_nlen : IFNAMSIZ;
132
133	out = obuf;
134	rem = sizeof(obuf);
135	if (namelen > 0) {
136		bcopy(sdl->sdl_data, out, namelen);
137		out += namelen;
138		rem -= namelen;
139		if (sdl->sdl_alen > 0) {
140			*out++ = ':';
141			rem--;
142		}
143	}
144
145	in = (const u_char *)sdl->sdl_data + sdl->sdl_nlen;
146	inlim = in + sdl->sdl_alen;
147
148	while (in < inlim && rem > 1) {
149		if (in != (const u_char *)sdl->sdl_data + sdl->sdl_nlen) {
150			*out++ = '.';
151			rem--;
152		}
153		i = *in++;
154		if (i > 0xf) {
155			if (rem < 3)
156				break;
157			*out++ = hexlist[i >> 4];
158			*out++ = hexlist[i & 0xf];
159			rem -= 2;
160		} else {
161			if (rem < 2)
162				break;
163			*out++ = hexlist[i];
164			rem--;
165		}
166	}
167	*out = 0;
168	return (obuf);
169}
170