1 /* $NetBSD: linkaddr.c,v 1.23 2022/04/19 20:32:15 rillig Exp $ */
2
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 * 3. 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 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)linkaddr.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: linkaddr.c,v 1.23 2022/04/19 20:32:15 rillig Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include <sys/types.h>
42 #include <sys/socket.h>
43 #include <net/if_dl.h>
44
45 #include <assert.h>
46 #include <string.h>
47
48 /* States*/
49 #define NAMING 0
50 #define GOTONE 1
51 #define GOTTWO 2
52 #define RESET 3
53 /* Inputs */
54 #define DIGIT (4*0)
55 #define END (4*1)
56 #define DELIM (4*2)
57 #define LETTER (4*3)
58
59 void
link_addr(const char * addr,struct sockaddr_dl * sdl)60 link_addr(const char *addr, struct sockaddr_dl *sdl)
61 {
62 char *cp = sdl->sdl_data;
63 char *cplim = sdl->sdl_len + (char *)(void *)sdl;
64 int byte = 0, state = NAMING;
65 size_t newaddr = 0; /* pacify gcc */
66
67 _DIAGASSERT(addr != NULL);
68 _DIAGASSERT(sdl != NULL);
69
70 (void)memset(&sdl->sdl_family, 0, (size_t)sdl->sdl_len - 1);
71 sdl->sdl_family = AF_LINK;
72 do {
73 state &= ~LETTER;
74 if ((*addr >= '0') && (*addr <= '9')) {
75 newaddr = *addr - '0';
76 } else if ((*addr >= 'a') && (*addr <= 'f')) {
77 newaddr = *addr - 'a' + 10;
78 } else if ((*addr >= 'A') && (*addr <= 'F')) {
79 newaddr = *addr - 'A' + 10;
80 } else if (*addr == 0) {
81 state |= END;
82 } else if (state == NAMING &&
83 (((*addr >= 'A') && (*addr <= 'Z')) ||
84 ((*addr >= 'a') && (*addr <= 'z'))))
85 state |= LETTER;
86 else
87 state |= DELIM;
88 addr++;
89 switch (state /* | INPUT */) {
90 case NAMING | DIGIT:
91 case NAMING | LETTER:
92 *cp++ = addr[-1];
93 continue;
94 case NAMING | DELIM:
95 state = RESET;
96 _DIAGASSERT(__type_fit(uint8_t, cp - sdl->sdl_data));
97 sdl->sdl_nlen = (uint8_t)(cp - sdl->sdl_data);
98 continue;
99 case GOTTWO | DIGIT:
100 *cp++ = byte;
101 /* FALLTHROUGH */
102 case RESET | DIGIT:
103 state = GOTONE;
104 byte = (int)newaddr;
105 continue;
106 case GOTONE | DIGIT:
107 state = GOTTWO;
108 byte = (int)newaddr + (byte << 4);
109 continue;
110 default: /* | DELIM */
111 state = RESET;
112 *cp++ = byte;
113 byte = 0;
114 continue;
115 case GOTONE | END:
116 case GOTTWO | END:
117 *cp++ = byte;
118 /* FALLTHROUGH */
119 case RESET | END:
120 break;
121 }
122 break;
123 } while (cp < cplim);
124
125 _DIAGASSERT(__type_fit(uint8_t, cp - LLADDR(sdl)));
126 sdl->sdl_alen = (uint8_t)(cp - LLADDR(sdl));
127 newaddr = cp - (char *)(void *)sdl;
128 if (newaddr > sizeof(*sdl)) {
129 _DIAGASSERT(__type_fit(uint8_t, newaddr));
130 sdl->sdl_len = (uint8_t)newaddr;
131 }
132 return;
133 }
134
135 static const char hexlist[16] = "0123456789abcdef";
136
137 char *
link_ntoa(const struct sockaddr_dl * sdl)138 link_ntoa(const struct sockaddr_dl *sdl)
139 {
140 static char obuf[64];
141 char *out = obuf;
142 size_t i;
143 const u_char *in = (const u_char *)CLLADDR(sdl);
144 const u_char *inlim = in + sdl->sdl_alen;
145 int firsttime = 1;
146
147 _DIAGASSERT(sdl != NULL);
148
149 #define ADDC(ch) \
150 do { \
151 if (out >= obuf + sizeof(obuf) - 1) \
152 return obuf; \
153 *out++ = (ch); \
154 } while (0)
155
156 /*
157 * This is not needed on the first call, as the static
158 * obuf wil be fully init'd to 0 by default. But after
159 * obuf has been returned to userspace the first time,
160 * anything may have been written to it, so, let's be safe.
161 *
162 * (An alternative method would be to make ADDC() more
163 * complex:
164 * if (out < obuf + sizeof(obuf) - ((ch) != '\0'))
165 * *out++ = (ch);
166 * so it never returns, and the final ADDC(0) always works
167 * but that evaluates 'ch' twice, and is slower, so ...)
168 */
169 obuf[sizeof(obuf) - 1] = '\0';
170
171 if (sdl->sdl_nlen) {
172 if (sdl->sdl_nlen >= sizeof(obuf))
173 i = sizeof(obuf) - 1;
174 else
175 i = sdl->sdl_nlen;
176 (void)memcpy(obuf, sdl->sdl_data, i);
177 out += i;
178 if (sdl->sdl_alen)
179 ADDC(':');
180 }
181 while (in < inlim) {
182 if (firsttime)
183 firsttime = 0;
184 else
185 ADDC('.');
186 i = *in++;
187 if (i > 0xf) {
188 size_t j = i & 0xf;
189 i >>= 4;
190 ADDC(hexlist[i]);
191 ADDC(hexlist[j]);
192 } else
193 ADDC(hexlist[i]);
194 }
195 ADDC('\0');
196 return obuf;
197 }
198