lib/libc/net/linkaddr.c

   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  * 3. 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  * @(#)linkaddr.c       8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: head/lib/libc/net/linkaddr.c 309688 2016-12-07 23:18:00Z glebius $
  31  */
  32
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <net/if.h>
  36 #include <net/if_dl.h>
  37 #include <string.h>
  38
  39 /* States*/
  40 #define NAMING  0
  41 #define GOTONE  1
  42 #define GOTTWO  2
  43 #define RESET   3
  44 /* Inputs */
  45 #define DIGIT   (4*0)
  46 #define END     (4*1)
  47 #define DELIM   (4*2)
  48 #define LETTER  (4*3)
  49
  50 void
  51 link_addr(const char *addr, struct sockaddr_dl *sdl)
  52 {
  53         char *cp = sdl->sdl_data;
  54         char *cplim = sdl->sdl_len + (char *)sdl;
  55         int byte = 0, state = NAMING, new;
  56
  57         bzero((char *)&sdl->sdl_family, sdl->sdl_len - 1);
  58         sdl->sdl_family = AF_LINK;
  59         do {
  60                 state &= ~LETTER;
  61                 if ((*addr >= '0') && (*addr <= '9')) {
  62                         new = *addr - '0';
  63                 } else if ((*addr >= 'a') && (*addr <= 'f')) {
  64                         new = *addr - 'a' + 10;
  65                 } else if ((*addr >= 'A') && (*addr <= 'F')) {
  66                         new = *addr - 'A' + 10;
  67                 } else if (*addr == 0) {
  68                         state |= END;
  69                 } else if (state == NAMING &&
  70                            (((*addr >= 'A') && (*addr <= 'Z')) ||
  71                            ((*addr >= 'a') && (*addr <= 'z'))))
  72                         state |= LETTER;
  73                 else
  74                         state |= DELIM;
  75                 addr++;
  76                 switch (state /* | INPUT */) {
  77                 case NAMING | DIGIT:
  78                 case NAMING | LETTER:
  79                         *cp++ = addr[-1];
  80                         continue;
  81                 case NAMING | DELIM:
  82                         state = RESET;
  83                         sdl->sdl_nlen = cp - sdl->sdl_data;
  84                         continue;
  85                 case GOTTWO | DIGIT:
  86                         *cp++ = byte;
  87                         /* FALLTHROUGH */
  88                 case RESET | DIGIT:
  89                         state = GOTONE;
  90                         byte = new;
  91                         continue;
  92                 case GOTONE | DIGIT:
  93                         state = GOTTWO;
  94                         byte = new + (byte << 4);
  95                         continue;
  96                 default: /* | DELIM */
  97                         state = RESET;
  98                         *cp++ = byte;
  99                         byte = 0;
 100                         continue;
 101                 case GOTONE | END:
 102                 case GOTTWO | END:
 103                         *cp++ = byte;
 104                         /* FALLTHROUGH */
 105                 case RESET | END:
 106                         break;
 107                 }
 108                 break;
 109         } while (cp < cplim);
 110         sdl->sdl_alen = cp - LLADDR(sdl);
 111         new = cp - (char *)sdl;
 112         if (new > sizeof(*sdl))
 113                 sdl->sdl_len = new;
 114         return;
 115 }
 116
 117 static const char hexlist[] = "0123456789abcdef";
 118
 119 char *
 120 link_ntoa(const struct sockaddr_dl *sdl)
 121 {
 122         static char obuf[64];
 123         _Static_assert(sizeof(obuf) >= IFNAMSIZ + 20, "obuf is too small");
 124         char *out;
 125         const u_char *in, *inlim;
 126         int namelen, i, rem;
 127
 128         namelen = (sdl->sdl_nlen <= IFNAMSIZ) ? sdl->sdl_nlen : IFNAMSIZ;
 129
 130         out = obuf;
 131         rem = sizeof(obuf);
 132         if (namelen > 0) {
 133                 bcopy(sdl->sdl_data, out, namelen);
 134                 out += namelen;
 135                 rem -= namelen;
 136                 if (sdl->sdl_alen > 0) {
 137                         *out++ = ':';
 138                         rem--;
 139                 }
 140         }
 141
 142         in = (const u_char *)sdl->sdl_data + sdl->sdl_nlen;
 143         inlim = in + sdl->sdl_alen;
 144
 145         while (in < inlim && rem > 1) {
 146                 if (in != (const u_char *)sdl->sdl_data + sdl->sdl_nlen) {
 147                         *out++ = '.';
 148                         rem--;
 149                 }
 150                 i = *in++;
 151                 if (i > 0xf) {
 152                         if (rem < 3)
 153                                 break;
 154                         *out++ = hexlist[i >> 4];
 155                         *out++ = hexlist[i & 0xf];
 156                         rem -= 2;
 157                 } else {
 158                         if (rem < 2)
 159                                 break;
 160                         *out++ = hexlist[i];
 161                         rem--;
 162                 }
 163         }
 164         *out = 0;
 165         return (obuf);
 166 }