lib/libc/ip/gethnmadr.c

   1 /*
   2  * Copyright (c) 1985, 1988 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that: (1) source distributions retain this entire copyright
   7  * notice and comment, and (2) distributions including binaries display
   8  * the following acknowledgement:  ``This product includes software
   9  * developed by the University of California, Berkeley and its contributors''
  10  * in the documentation or other materials provided with the distribution
  11  * and in all advertising materials mentioning features or use of this
  12  * software. Neither the name of the University nor the names of its
  13  * contributors may be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static char sccsid[] = "@(#)gethostnamadr.c     6.41 (Berkeley) 6/1/90";
  22 #endif /* LIBC_SCCS and not lint */
  23
  24 #ifdef _MINIX
  25 #include <sys/types.h>
  26 #include <ctype.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29
  30 #include <net/hton.h>
  31 #include <net/gen/nameser.h>
  32 #include <net/gen/netdb.h>
  33 #include <net/gen/in.h>
  34 #include <net/gen/inet.h>
  35 #include <net/gen/resolv.h>
  36 #include <net/gen/socket.h>
  37 #else
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <netinet/in.h>
  41 #include <ctype.h>
  42 #include <netdb.h>
  43 #include <stdio.h>
  44 #include <arpa/inet.h>
  45 #include <arpa/nameser.h>
  46 #include <resolv.h>
  47 #endif /* AMOEABA */
  48
  49 #define MAXALIASES      35
  50 #define MAXADDRS        35
  51
  52 static char *h_addr_ptrs[MAXADDRS + 1];
  53
  54 #ifdef _MINIX
  55 union querybuf;
  56
  57 extern int dn_skipname _ARGS(( const u_char *comp_dn, const u_char *eom ));
  58 #define getshort _getshort
  59 static struct hostent *getanswer _ARGS(( union querybuf *answer, int anslen,
  60         int iquery ));
  61 #define bcmp memcmp
  62 #define bcopy(s, d, l) memcpy(d, s, l)
  63 #endif /* _MINIX */
  64
  65 static struct hostent host;
  66 static char *host_aliases[MAXALIASES];
  67 static char hostbuf[BUFSIZ+1];
  68 static struct in_addr host_addr;
  69
  70 #ifndef _MINIX
  71 char *strpbrk();
  72 #endif /* !_MINIX */
  73
  74 #if PACKETSZ > 1024
  75 #define MAXPACKET       PACKETSZ
  76 #else
  77 #define MAXPACKET       1024
  78 #endif
  79
  80 typedef union querybuf
  81 {
  82         dns_hdr_t hdr;
  83         u_char buf[MAXPACKET];
  84 } querybuf_t;
  85
  86 typedef union align {
  87     long al;
  88     char ac;
  89 } align_t;
  90
  91 static struct hostent *
  92 getanswer(answer, anslen, iquery)
  93         querybuf_t *answer;
  94         int anslen;
  95         int iquery;
  96 {
  97         register dns_hdr_t *hp;
  98         register u_char *cp;
  99         register int n;
 100         u_char *eom;
 101         char *bp, **ap;
 102         int type, class, buflen, ancount, qdcount;
 103         int haveanswer, getclass = C_ANY;
 104         char **hap;
 105
 106         eom = answer->buf + anslen;
 107         /*
 108          * find first satisfactory answer
 109          */
 110         hp = &answer->hdr;
 111         ancount = ntohs(hp->dh_ancount);
 112         qdcount = ntohs(hp->dh_qdcount);
 113         bp = hostbuf;
 114         buflen = sizeof(hostbuf);
 115         cp = answer->buf + sizeof(dns_hdr_t);
 116         if (qdcount) {
 117                 if (iquery) {
 118                         if ((n = dn_expand((u_char *)answer->buf, eom,
 119                              cp, (u_char *)bp, buflen)) < 0) {
 120                                 h_errno = NO_RECOVERY;
 121                                 return ((struct hostent *) NULL);
 122                         }
 123                         cp += n + QFIXEDSZ;
 124                         host.h_name = bp;
 125                         n = strlen(bp) + 1;
 126                         bp += n;
 127                         buflen -= n;
 128                 } else
 129                         cp += dn_skipname(cp, eom) + QFIXEDSZ;
 130                 while (--qdcount > 0)
 131                         cp += dn_skipname(cp, eom) + QFIXEDSZ;
 132         } else if (iquery) {
 133                 if (hp->dh_flag1 & DHF_AA)
 134                         h_errno = HOST_NOT_FOUND;
 135                 else
 136                         h_errno = TRY_AGAIN;
 137                 return ((struct hostent *) NULL);
 138         }
 139         ap = host_aliases;
 140         *ap = NULL;
 141         host.h_aliases = host_aliases;
 142         hap = h_addr_ptrs;
 143         *hap = NULL;
 144 #if BSD >= 43 || defined(h_addr)        /* new-style hostent structure */
 145         host.h_addr_list = h_addr_ptrs;
 146 #endif
 147         haveanswer = 0;
 148         while (--ancount >= 0 && cp < eom) {
 149                 if ((n = dn_expand((u_char *)answer->buf, eom, cp, (u_char *)bp,
 150                         buflen)) < 0)
 151                         break;
 152                 cp += n;
 153                 type = getshort(cp);
 154                 cp += sizeof(u_short);
 155                 class = getshort(cp);
 156                 cp += sizeof(u_short) + sizeof(u_long);
 157                 n = getshort(cp);
 158                 cp += sizeof(u_short);
 159                 if (type == T_CNAME) {
 160                         cp += n;
 161                         if (ap >= &host_aliases[MAXALIASES-1])
 162                                 continue;
 163                         *ap++ = bp;
 164                         n = strlen(bp) + 1;
 165                         bp += n;
 166                         buflen -= n;
 167                         continue;
 168                 }
 169                 if (iquery && type == T_PTR) {
 170                         if ((n = dn_expand((u8_t *)answer->buf, eom,
 171                             cp, (u8_t *)bp, buflen)) < 0) {
 172                                 cp += n;
 173                                 continue;
 174                         }
 175                         cp += n;
 176                         host.h_name = bp;
 177                         return(&host);
 178                 }
 179                 if (iquery || type != T_A)  {
 180 #ifdef DEBUG
 181                         if (_res.options & RES_DEBUG)
 182                                 printf("unexpected answer type %d, size %d\n",
 183                                         type, n);
 184 #endif
 185                         cp += n;
 186                         continue;
 187                 }
 188                 if (haveanswer) {
 189                         if (n != host.h_length) {
 190                                 cp += n;
 191                                 continue;
 192                         }
 193                         if (class != getclass) {
 194                                 cp += n;
 195                                 continue;
 196                         }
 197                 } else {
 198                         host.h_length = n;
 199                         getclass = class;
 200                         host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
 201                         if (!iquery) {
 202                                 host.h_name = bp;
 203                                 bp += strlen(bp) + 1;
 204                         }
 205                 }
 206
 207                 bp += (size_t)(sizeof(align_t) -
 208                                                 ((u_long)bp % sizeof(align_t)));
 209
 210                 if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
 211 #ifdef DEBUG
 212                         if (_res.options & RES_DEBUG)
 213                                 printf("size (%d) too big\n", n);
 214 #endif
 215                         break;
 216                 }
 217                 bcopy(cp, *hap++ = bp, n);
 218                 bp +=n;
 219                 cp += n;
 220                 haveanswer++;
 221         }
 222         if (haveanswer) {
 223                 *ap = NULL;
 224 #if BSD >= 43 || defined(h_addr)        /* new-style hostent structure */
 225                 *hap = NULL;
 226 #else
 227                 host.h_addr = h_addr_ptrs[0];
 228 #endif
 229                 return (&host);
 230         } else {
 231                 h_errno = TRY_AGAIN;
 232                 return ((struct hostent *) NULL);
 233         }
 234 }
 235
 236 struct hostent *
 237 gethostbyname(name)
 238         _CONST char *name;
 239 {
 240         querybuf_t buf;
 241         register _CONST char *cp;
 242         int n;
 243
 244         /*
 245          * disallow names consisting only of digits/dots, unless
 246          * they end in a dot.
 247          */
 248         if (isdigit(name[0]))
 249                 for (cp = name;; ++cp) {
 250                         if (!*cp) {
 251                                 if (*--cp == '.')
 252                                         break;
 253                                 /*
 254                                  * All-numeric, no dot at the end.
 255                                  * Fake up a hostent as if we'd actually
 256                                  * done a lookup.  What if someone types
 257                                  * 255.255.255.255?  The test below will
 258                                  * succeed spuriously... ???
 259                                  */
 260                                 if ((host_addr.s_addr = inet_addr(name)) == -1) {
 261                                         h_errno = HOST_NOT_FOUND;
 262                                         return((struct hostent *) NULL);
 263                                 }
 264                                 host.h_name = (char *) name;
 265                                 host.h_aliases = host_aliases;
 266                                 host_aliases[0] = NULL;
 267                                 host.h_addrtype = AF_INET;
 268                                 host.h_length = sizeof(u_long);
 269                                 h_addr_ptrs[0] = (char *)&host_addr;
 270                                 h_addr_ptrs[1] = (char *)0;
 271 #if BSD >= 43 || defined(h_addr)        /* new-style hostent structure */
 272                                 host.h_addr_list = h_addr_ptrs;
 273 #else
 274                                 host.h_addr = h_addr_ptrs[0];
 275 #endif
 276                                 return (&host);
 277                         }
 278                         if (!isdigit(*cp) && *cp != '.')
 279                                 break;
 280                 }
 281
 282         if ((n = res_search((char*)name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
 283 #ifdef DEBUG
 284                 if (_res.options & RES_DEBUG)
 285                         printf("res_search failed\n");
 286 #endif
 287                 return ((struct hostent *) NULL);
 288         }
 289         return (getanswer(&buf, n, 0));
 290 }
 291
 292 struct hostent *
 293 gethostbyaddr(addr, len, type)
 294         const char *addr;
 295         int len, type;
 296 {
 297         int n;
 298         querybuf_t buf;
 299         register struct hostent *hp;
 300         char qbuf[MAXDNAME];
 301
 302         if (type != AF_INET)
 303                 return ((struct hostent *) NULL);
 304         (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 305                 ((unsigned)addr[3] & 0xff),
 306                 ((unsigned)addr[2] & 0xff),
 307                 ((unsigned)addr[1] & 0xff),
 308                 ((unsigned)addr[0] & 0xff));
 309         n = res_query(qbuf, C_IN, T_PTR, (u8_t *)&buf, sizeof(buf));
 310         if (n < 0) {
 311 #ifdef DEBUG
 312                 if (_res.options & RES_DEBUG)
 313                         printf("res_query failed\n");
 314 #endif
 315                 return ((struct hostent *) NULL);
 316         }
 317         hp = getanswer(&buf, n, 1);
 318         if (hp == NULL)
 319                 return ((struct hostent *) NULL);
 320         hp->h_addrtype = type;
 321         hp->h_length = len;
 322         h_addr_ptrs[0] = (char *)&host_addr;
 323         h_addr_ptrs[1] = (char *)0;
 324         host_addr = *(struct in_addr *)addr;
 325 #if BSD < 43 && !defined(h_addr)        /* new-style hostent structure */
 326         hp->h_addr = h_addr_ptrs[0];
 327 #endif
 328         return(hp);
 329 }