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 * 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/types.h> 33 #include <sys/socket.h> 34 35 #include <net/if.h> 36 #include <net/if_dl.h> 37 38 #include <assert.h> 39 #include <stdint.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 53 void 54 link_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 } 119 120 char * 121 link_ntoa(const struct sockaddr_dl *sdl) 122 { 123 static char obuf[64]; 124 size_t buflen; 125 _Static_assert(sizeof(obuf) >= IFNAMSIZ + 20, "obuf is too small"); 126 127 /* 128 * Ignoring the return value of link_ntoa_r() is safe here because it 129 * always writes the terminating NUL. This preserves the traditional 130 * behaviour of link_ntoa(). 131 */ 132 buflen = sizeof(obuf); 133 (void)link_ntoa_r(sdl, obuf, &buflen); 134 return obuf; 135 } 136 137 int 138 link_ntoa_r(const struct sockaddr_dl *sdl, char *obuf, size_t *buflen) 139 { 140 static const char hexlist[] = "0123456789abcdef"; 141 char *out; 142 const u_char *in, *inlim; 143 int namelen, i, rem; 144 size_t needed; 145 146 assert(sdl); 147 assert(buflen); 148 /* obuf may be null */ 149 150 needed = 1; /* 1 for the NUL */ 151 out = obuf; 152 if (obuf) 153 rem = *buflen; 154 else 155 rem = 0; 156 157 /* 158 * Check if at least n bytes are available in the output buffer, plus 1 for the 159 * trailing NUL. If not, set rem = 0 so we stop writing. 160 * Either way, increment needed by the amount we would have written. 161 */ 162 #define CHECK(n) do { \ 163 if ((SIZE_MAX - (n)) >= needed) \ 164 needed += (n); \ 165 if (rem >= ((n) + 1)) \ 166 rem -= (n); \ 167 else \ 168 rem = 0; \ 169 } while (0) 170 171 /* 172 * Write the char c to the output buffer, unless the buffer is full. 173 * Note that if obuf is NULL, rem is always zero. 174 */ 175 #define OUT(c) do { \ 176 if (rem > 0) \ 177 *out++ = (c); \ 178 } while (0) 179 180 namelen = (sdl->sdl_nlen <= IFNAMSIZ) ? sdl->sdl_nlen : IFNAMSIZ; 181 if (namelen > 0) { 182 CHECK(namelen); 183 if (rem > 0) { 184 bcopy(sdl->sdl_data, out, namelen); 185 out += namelen; 186 } 187 188 if (sdl->sdl_alen > 0) { 189 CHECK(1); 190 OUT(':'); 191 } 192 } 193 194 in = (const u_char *)LLADDR(sdl); 195 inlim = in + sdl->sdl_alen; 196 197 while (in < inlim) { 198 if (in != (const u_char *)LLADDR(sdl)) { 199 CHECK(1); 200 OUT('.'); 201 } 202 i = *in++; 203 if (i > 0xf) { 204 CHECK(2); 205 OUT(hexlist[i >> 4]); 206 OUT(hexlist[i & 0xf]); 207 } else { 208 CHECK(1); 209 OUT(hexlist[i]); 210 } 211 } 212 213 #undef CHECK 214 #undef OUT 215 216 /* 217 * We always leave enough room for the NUL if possible, but the user 218 * might have passed a NULL or zero-length buffer. 219 */ 220 if (out && *buflen) 221 *out = '\0'; 222 223 *buflen = needed; 224 return ((rem > 0) ? 0 : -1); 225 } 226