lib/libc/net/ethers.c

   1 /*      $NetBSD: ethers.c,v 1.23 2012/03/20 17:44:18 matt Exp $ */
   2
   3 /*
   4  * ethers(3N) a la Sun.
   5  *
   6  * Written by Roland McGrath <roland@frob.com> 10/14/93.
   7  * Public domain.
   8  */
   9
  10 #include <sys/cdefs.h>
  11 #if defined(LIBC_SCCS) && !defined(lint)
  12 __RCSID("$NetBSD: ethers.c,v 1.23 2012/03/20 17:44:18 matt Exp $");
  13 #endif /* LIBC_SCCS and not lint */
  14
  15 #include "namespace.h"
  16 #include <sys/param.h>
  17 #include <sys/socket.h>
  18
  19 #include <net/if.h>
  20 #include <net/if_ether.h>
  21 #include <netinet/in.h>
  22
  23 #include <assert.h>
  24 #include <errno.h>
  25 #include <paths.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 #ifdef YP
  31 #include <rpcsvc/ypclnt.h>
  32 #endif
  33
  34 #ifdef __weak_alias
  35 __weak_alias(ether_aton,_ether_aton)
  36 __weak_alias(ether_hostton,_ether_hostton)
  37 __weak_alias(ether_line,_ether_line)
  38 __weak_alias(ether_ntoa,_ether_ntoa)
  39 __weak_alias(ether_ntohost,_ether_ntohost)
  40 #endif
  41
  42 #ifndef _PATH_ETHERS
  43 #define _PATH_ETHERS "/etc/ethers"
  44 #endif
  45
  46 char *
  47 ether_ntoa(const struct ether_addr *e)
  48 {
  49         static char a[18];
  50
  51         _DIAGASSERT(e != NULL);
  52
  53         (void) snprintf(a, sizeof a, "%02x:%02x:%02x:%02x:%02x:%02x",
  54             e->ether_addr_octet[0], e->ether_addr_octet[1],
  55             e->ether_addr_octet[2], e->ether_addr_octet[3],
  56             e->ether_addr_octet[4], e->ether_addr_octet[5]);
  57         return a;
  58 }
  59
  60 struct ether_addr *
  61 ether_aton(const char *s)
  62 {
  63         static struct ether_addr n;
  64         u_int i[6];
  65
  66         _DIAGASSERT(s != NULL);
  67
  68         if (sscanf(s, " %x:%x:%x:%x:%x:%x ", &i[0], &i[1],
  69             &i[2], &i[3], &i[4], &i[5]) == 6) {
  70                 n.ether_addr_octet[0] = (u_char)i[0];
  71                 n.ether_addr_octet[1] = (u_char)i[1];
  72                 n.ether_addr_octet[2] = (u_char)i[2];
  73                 n.ether_addr_octet[3] = (u_char)i[3];
  74                 n.ether_addr_octet[4] = (u_char)i[4];
  75                 n.ether_addr_octet[5] = (u_char)i[5];
  76                 return &n;
  77         }
  78         return NULL;
  79 }
  80
  81 int
  82 ether_ntohost(char *hostname, const struct ether_addr *e)
  83 {
  84         FILE *f;
  85         char *p;
  86         size_t len;
  87         struct ether_addr try;
  88 #ifdef YP
  89         char trybuf[sizeof "xx:xx:xx:xx:xx:xx"];
  90         int trylen;
  91 #endif
  92
  93         _DIAGASSERT(hostname != NULL);
  94         _DIAGASSERT(e != NULL);
  95
  96 #ifdef YP
  97         trylen = snprintf(trybuf, sizeof trybuf, "%x:%x:%x:%x:%x:%x",
  98             e->ether_addr_octet[0], e->ether_addr_octet[1],
  99             e->ether_addr_octet[2], e->ether_addr_octet[3],
 100             e->ether_addr_octet[4], e->ether_addr_octet[5]);
 101 #endif
 102
 103         f = fopen(_PATH_ETHERS, "r");
 104         if (f == NULL)
 105                 return -1;
 106         while ((p = fgetln(f, &len)) != NULL) {
 107                 if (p[len - 1] != '\n')
 108                         continue;               /* skip lines w/o \n */
 109                 p[--len] = '\0';
 110 #ifdef YP
 111                 /* A + in the file means try YP now.  */
 112                 if (len == 1 && *p == '+') {
 113                         char *ypbuf, *ypdom;
 114                         int ypbuflen;
 115
 116                         if (yp_get_default_domain(&ypdom))
 117                                 continue;
 118                         if (yp_match(ypdom, "ethers.byaddr", trybuf,
 119                             trylen, &ypbuf, &ypbuflen))
 120                                 continue;
 121                         if (ether_line(ypbuf, &try, hostname) == 0) {
 122                                 free(ypbuf);
 123                                 (void)fclose(f);
 124                                 return 0;
 125                         }
 126                         free(ypbuf);
 127                         continue;
 128                 }
 129 #endif
 130                 if (ether_line(p, &try, hostname) == 0 &&
 131                     memcmp(&try, e, sizeof try) == 0) {
 132                         (void)fclose(f);
 133                         return 0;
 134                 }
 135         }
 136         (void)fclose(f);
 137         errno = ENOENT;
 138         return -1;
 139 }
 140
 141 int
 142 ether_hostton(const char *hostname, struct ether_addr *e)
 143 {
 144         FILE *f;
 145         char *p;
 146         size_t len;
 147         char try[MAXHOSTNAMELEN + 1];
 148 #ifdef YP
 149         int hostlen = (int)strlen(hostname);
 150 #endif
 151
 152         _DIAGASSERT(hostname != NULL);
 153         _DIAGASSERT(e != NULL);
 154
 155         f = fopen(_PATH_ETHERS, "r");
 156         if (f==NULL)
 157                 return -1;
 158
 159         while ((p = fgetln(f, &len)) != NULL) {
 160                 if (p[len - 1] != '\n')
 161                         continue;               /* skip lines w/o \n */
 162                 p[--len] = '\0';
 163 #ifdef YP
 164                 /* A + in the file means try YP now.  */
 165                 if (len == 1 && *p == '+') {
 166                         char *ypbuf, *ypdom;
 167                         int ypbuflen;
 168
 169                         if (yp_get_default_domain(&ypdom))
 170                                 continue;
 171                         if (yp_match(ypdom, "ethers.byname", hostname, hostlen,
 172                             &ypbuf, &ypbuflen))
 173                                 continue;
 174                         if (ether_line(ypbuf, e, try) == 0) {
 175                                 free(ypbuf);
 176                                 (void)fclose(f);
 177                                 return 0;
 178                         }
 179                         free(ypbuf);
 180                         continue;
 181                 }
 182 #endif
 183                 if (ether_line(p, e, try) == 0 && strcmp(hostname, try) == 0) {
 184                         (void)fclose(f);
 185                         return 0;
 186                 }
 187         }
 188         (void)fclose(f);
 189         errno = ENOENT;
 190         return -1;
 191 }
 192
 193 int
 194 ether_line(const char *l, struct ether_addr *e, char *hostname)
 195 {
 196         u_int i[6];
 197
 198 #define S2(arg) #arg
 199 #define S1(arg) S2(arg)
 200         static const char fmt[] = " %x:%x:%x:%x:%x:%x"
 201             " %" S1(MAXHOSTNAMELEN) "s\n";
 202 #undef S2
 203 #undef S1
 204
 205         _DIAGASSERT(l != NULL);
 206         _DIAGASSERT(e != NULL);
 207         _DIAGASSERT(hostname != NULL);
 208
 209         if (sscanf(l, fmt,
 210             &i[0], &i[1], &i[2], &i[3], &i[4], &i[5], hostname) == 7) {
 211                 e->ether_addr_octet[0] = (u_char)i[0];
 212                 e->ether_addr_octet[1] = (u_char)i[1];
 213                 e->ether_addr_octet[2] = (u_char)i[2];
 214                 e->ether_addr_octet[3] = (u_char)i[3];
 215                 e->ether_addr_octet[4] = (u_char)i[4];
 216                 e->ether_addr_octet[5] = (u_char)i[5];
 217                 return 0;
 218         }
 219         errno = EINVAL;
 220         return -1;
 221 }