1 /*- 2 * Copyright (c) 1985, 1988, 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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * - 33 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 34 * 35 * Permission to use, copy, modify, and distribute this software for any 36 * purpose with or without fee is hereby granted, provided that the above 37 * copyright notice and this permission notice appear in all copies, and that 38 * the name of Digital Equipment Corporation not be used in advertising or 39 * publicity pertaining to distribution of the document or software without 40 * specific, written prior permission. 41 * 42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 44 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 49 * SOFTWARE. 50 * - 51 * --Copyright-- 52 */ 53 54 #if defined(LIBC_SCCS) && !defined(lint) 55 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 56 static char rcsid[] = "$Id: getnetbydns.c,v 1.1 1994/09/25 02:12:20 pst Exp $"; 57 #endif /* LIBC_SCCS and not lint */ 58 59 #include <sys/param.h> 60 #include <sys/socket.h> 61 #include <netinet/in.h> 62 #include <arpa/inet.h> 63 #include <arpa/nameser.h> 64 #include <netdb.h> 65 #include <resolv.h> 66 #include <stdio.h> 67 #include <ctype.h> 68 #include <errno.h> 69 #include <string.h> 70 #include <syslog.h> 71 72 #define BYNAME 0 73 #define BYADDR 1 74 75 #define MAXALIASES 35 76 #define MAXADDRS 35 77 78 #if PACKETSZ > 1024 79 #define MAXPACKET PACKETSZ 80 #else 81 #define MAXPACKET 1024 82 #endif 83 84 typedef union { 85 HEADER hdr; 86 u_char buf[MAXPACKET]; 87 } querybuf; 88 89 typedef union { 90 int32_t al; 91 char ac; 92 } align; 93 94 extern int h_errno; 95 96 static struct netent * 97 getnetanswer(answer, anslen, net_i) 98 querybuf *answer; 99 int anslen; 100 int net_i; 101 { 102 103 register HEADER *hp; 104 register u_char *cp; 105 register int n; 106 u_char *eom; 107 int type, class, buflen, ancount, qdcount, 108 haveanswer, i, nchar; 109 char aux1[30], aux2[30], ans[30], 110 *in, *st, *pauxt, *bp, **ap, 111 *paux1 = &aux1[0], 112 *paux2 = &aux2[0], 113 flag = 0; 114 static struct netent net_entry; 115 static char *net_aliases[MAXALIASES], 116 netbuf[BUFSIZ+1]; 117 118 /* 119 * find first satisfactory answer 120 * 121 * answer --> +------------+ ( MESSAGE ) 122 * | Header | 123 * +------------+ 124 * | Question | the question for the name server 125 * +------------+ 126 * | Answer | RRs answering the question 127 * +------------+ 128 * | Authority | RRs pointing toward an authority 129 * | Additional | RRs holding additional information 130 * +------------+ 131 */ 132 eom = answer->buf + anslen; 133 hp = &answer->hdr; 134 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 135 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 136 bp = netbuf; 137 buflen = sizeof(netbuf); 138 cp = answer->buf + HFIXEDSZ; 139 if (!qdcount) { 140 if (hp->aa) 141 h_errno = HOST_NOT_FOUND; 142 else 143 h_errno = TRY_AGAIN; 144 145 return ((struct netent *) NULL); 146 } 147 while (qdcount-- > 0){ 148 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 149 } 150 ap = net_aliases; 151 *ap = NULL; 152 net_entry.n_aliases = net_aliases; 153 haveanswer = 0; 154 while (--ancount >= 0 && cp < eom) { 155 n = dn_expand(answer->buf, eom, cp, bp, buflen); 156 if (n < 0) 157 break; 158 cp += n; 159 ans[0] = '\0'; 160 (void)strcpy(&ans[0], bp); 161 GETSHORT(type, cp); 162 GETSHORT(class, cp); 163 cp += INT32SZ; /* TTL */ 164 GETSHORT(n, cp); 165 if (class == C_IN && type == T_PTR) { 166 n = dn_expand(answer->buf, eom, cp, bp, buflen); 167 if (n < 0) { 168 cp += n; 169 return (NULL); 170 } 171 cp += n; 172 *ap++ = bp; 173 bp += (strlen(bp) + 1); 174 net_entry.n_addrtype = (class == C_IN) 175 ? AF_INET 176 : AF_UNSPEC; 177 haveanswer++; 178 } 179 } 180 if (haveanswer) { 181 *ap = NULL; 182 switch (net_i) { 183 case BYADDR : 184 net_entry.n_name = *net_entry.n_aliases; 185 net_entry.n_net = 0L; 186 break; 187 case BYNAME : 188 in = *net_entry.n_aliases; 189 net_entry.n_name = &ans[0]; 190 aux2[0] = '\0'; 191 for (i = 0; i < 4; i++) { 192 for (st = in, nchar = 0; 193 *st != '.'; 194 st++, nchar++) 195 ; 196 if (nchar != 1 || *in != '0' || flag) { 197 flag = 1; 198 (void)strncpy(paux1, 199 (i==0) ?in :in-1, 200 (i==0) ?nchar :nchar+1); 201 paux1[(i==0) ?nchar :nchar+1] = '\0'; 202 pauxt = paux2; 203 paux2 = strcat(paux1, paux2); 204 paux1 = pauxt; 205 } 206 in = ++st; 207 } 208 net_entry.n_net = inet_network(paux2); 209 } 210 net_entry.n_aliases++; 211 return (&net_entry); 212 } else { 213 h_errno = TRY_AGAIN; 214 return ((struct netent *) NULL); 215 } 216 } 217 218 struct netent * 219 _getnetbydnsaddr(net, net_type) 220 register long net; 221 register int net_type; 222 { 223 unsigned int netbr[4]; 224 int nn, anslen; 225 querybuf buf; 226 char qbuf[MAXDNAME]; 227 unsigned long net2; 228 struct netent *net_entry; 229 230 if (net_type != AF_INET) 231 return (NULL); 232 233 for (nn = 4, net2 = net; net2; net2 >>= 8) { 234 netbr[--nn] = net2 & 0xff; 235 } 236 switch (nn) { 237 case 3: /* Class A */ 238 (void)sprintf(qbuf, "0.0.0.%u.in-addr.arpa", 239 netbr[3]); 240 break; 241 case 2: /* Class B */ 242 (void)sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", 243 netbr[3], netbr[2]); 244 break; 245 case 1: /* Class C */ 246 (void)sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", 247 netbr[3], netbr[2], netbr[1]); 248 break; 249 case 0: /* Class D - E */ 250 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 251 netbr[3], netbr[2], netbr[1], netbr[0]); 252 break; 253 } 254 anslen = res_query(qbuf, C_IN, T_PTR, buf.buf, sizeof buf.buf); 255 if (anslen < 0) { 256 if (_res.options & RES_DEBUG) 257 printf("res_query failed\n"); 258 return (NULL); 259 } 260 net_entry = getnetanswer(&buf, anslen, BYADDR); 261 if (net_entry) { 262 unsigned u_net = net; /* maybe net should be unsigned ? */ 263 264 /* Strip trailing zeros */ 265 while ((u_net & 0xff) == 0 && u_net != 0) { 266 u_net >>= 8; 267 } 268 net_entry->n_net = u_net; 269 } 270 return (net_entry); 271 } 272 273 struct netent * 274 _getnetbydnsname(net) 275 register const char *net; 276 { 277 int anslen; 278 querybuf buf; 279 char qbuf[MAXDNAME]; 280 281 (void)strcpy(&qbuf[0],net); 282 anslen = res_search(qbuf, C_IN, T_PTR, buf.buf, sizeof buf.buf); 283 if (anslen < 0) { 284 if (_res.options & RES_DEBUG) 285 printf("res_query failed\n"); 286 return NULL; 287 } 288 return getnetanswer(&buf, anslen, BYNAME); 289 } 290 291 void 292 _setnetdnsent(stayopen) 293 int stayopen; 294 { 295 if (stayopen) 296 _res.options |= RES_STAYOPEN | RES_USEVC; 297 } 298 299 void 300 _endnetdnsent() 301 { 302 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 303 _res_close(); 304 } 305