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 1.3 1995/05/30 05:40:46 rgrimes 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 <unistd.h> 68 #include <ctype.h> 69 #include <errno.h> 70 #include <string.h> 71 #include <syslog.h> 72 73 #define BYNAME 0 74 #define BYADDR 1 75 76 #define MAXALIASES 35 77 #define MAXADDRS 35 78 79 #if PACKETSZ > 1024 80 #define MAXPACKET PACKETSZ 81 #else 82 #define MAXPACKET 1024 83 #endif 84 85 typedef union { 86 HEADER hdr; 87 u_char buf[MAXPACKET]; 88 } querybuf; 89 90 typedef union { 91 int32_t al; 92 char ac; 93 } align; 94 95 extern int h_errno; 96 97 static struct netent * 98 getnetanswer(answer, anslen, net_i) 99 querybuf *answer; 100 int anslen; 101 int net_i; 102 { 103 104 register HEADER *hp; 105 register u_char *cp; 106 register int n; 107 u_char *eom; 108 int type, class, buflen, ancount, qdcount, 109 haveanswer, i, nchar; 110 char aux1[30], aux2[30], ans[30], 111 *in, *st, *pauxt, *bp, **ap, 112 *paux1 = &aux1[0], 113 *paux2 = &aux2[0], 114 flag = 0; 115 static struct netent net_entry; 116 static char *net_aliases[MAXALIASES], 117 netbuf[BUFSIZ+1]; 118 119 /* 120 * find first satisfactory answer 121 * 122 * answer --> +------------+ ( MESSAGE ) 123 * | Header | 124 * +------------+ 125 * | Question | the question for the name server 126 * +------------+ 127 * | Answer | RRs answering the question 128 * +------------+ 129 * | Authority | RRs pointing toward an authority 130 * | Additional | RRs holding additional information 131 * +------------+ 132 */ 133 eom = answer->buf + anslen; 134 hp = &answer->hdr; 135 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 136 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 137 bp = netbuf; 138 buflen = sizeof(netbuf); 139 cp = answer->buf + HFIXEDSZ; 140 if (!qdcount) { 141 if (hp->aa) 142 h_errno = HOST_NOT_FOUND; 143 else 144 h_errno = TRY_AGAIN; 145 146 return ((struct netent *) NULL); 147 } 148 while (qdcount-- > 0){ 149 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 150 } 151 ap = net_aliases; 152 *ap = NULL; 153 net_entry.n_aliases = net_aliases; 154 haveanswer = 0; 155 while (--ancount >= 0 && cp < eom) { 156 n = dn_expand(answer->buf, eom, cp, bp, buflen); 157 if (n < 0) 158 break; 159 cp += n; 160 ans[0] = '\0'; 161 (void)strcpy(&ans[0], bp); 162 GETSHORT(type, cp); 163 GETSHORT(class, cp); 164 cp += INT32SZ; /* TTL */ 165 GETSHORT(n, cp); 166 if (class == C_IN && type == T_PTR) { 167 n = dn_expand(answer->buf, eom, cp, bp, buflen); 168 if (n < 0) { 169 cp += n; 170 return (NULL); 171 } 172 cp += n; 173 *ap++ = bp; 174 bp += (strlen(bp) + 1); 175 net_entry.n_addrtype = (class == C_IN) 176 ? AF_INET 177 : AF_UNSPEC; 178 haveanswer++; 179 } 180 } 181 if (haveanswer) { 182 *ap = NULL; 183 switch (net_i) { 184 case BYADDR : 185 net_entry.n_name = *net_entry.n_aliases; 186 net_entry.n_net = 0L; 187 break; 188 case BYNAME : 189 in = *net_entry.n_aliases; 190 net_entry.n_name = &ans[0]; 191 aux2[0] = '\0'; 192 for (i = 0; i < 4; i++) { 193 for (st = in, nchar = 0; 194 *st != '.'; 195 st++, nchar++) 196 ; 197 if (nchar != 1 || *in != '0' || flag) { 198 flag = 1; 199 (void)strncpy(paux1, 200 (i==0) ?in :in-1, 201 (i==0) ?nchar :nchar+1); 202 paux1[(i==0) ?nchar :nchar+1] = '\0'; 203 pauxt = paux2; 204 paux2 = strcat(paux1, paux2); 205 paux1 = pauxt; 206 } 207 in = ++st; 208 } 209 net_entry.n_net = inet_network(paux2); 210 } 211 net_entry.n_aliases++; 212 return (&net_entry); 213 } else { 214 h_errno = TRY_AGAIN; 215 return ((struct netent *) NULL); 216 } 217 } 218 219 struct netent * 220 _getnetbydnsaddr(net, net_type) 221 register long net; 222 register int net_type; 223 { 224 unsigned int netbr[4]; 225 int nn, anslen; 226 querybuf buf; 227 char qbuf[MAXDNAME]; 228 unsigned long net2; 229 struct netent *net_entry; 230 231 if (net_type != AF_INET) 232 return (NULL); 233 234 for (nn = 4, net2 = net; net2; net2 >>= 8) { 235 netbr[--nn] = net2 & 0xff; 236 } 237 switch (nn) { 238 case 3: /* Class A */ 239 (void)sprintf(qbuf, "0.0.0.%u.in-addr.arpa", 240 netbr[3]); 241 break; 242 case 2: /* Class B */ 243 (void)sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", 244 netbr[3], netbr[2]); 245 break; 246 case 1: /* Class C */ 247 (void)sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", 248 netbr[3], netbr[2], netbr[1]); 249 break; 250 case 0: /* Class D - E */ 251 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 252 netbr[3], netbr[2], netbr[1], netbr[0]); 253 break; 254 } 255 anslen = res_query(qbuf, C_IN, T_PTR, buf.buf, sizeof buf.buf); 256 if (anslen < 0) { 257 if (_res.options & RES_DEBUG) 258 printf("res_query failed\n"); 259 return (NULL); 260 } 261 net_entry = getnetanswer(&buf, anslen, BYADDR); 262 if (net_entry) { 263 unsigned u_net = net; /* maybe net should be unsigned ? */ 264 265 /* Strip trailing zeros */ 266 while ((u_net & 0xff) == 0 && u_net != 0) { 267 u_net >>= 8; 268 } 269 net_entry->n_net = u_net; 270 } 271 return (net_entry); 272 } 273 274 struct netent * 275 _getnetbydnsname(net) 276 register const char *net; 277 { 278 int anslen; 279 querybuf buf; 280 char qbuf[MAXDNAME]; 281 282 (void)strcpy(&qbuf[0],net); 283 anslen = res_search(qbuf, C_IN, T_PTR, buf.buf, sizeof buf.buf); 284 if (anslen < 0) { 285 if (_res.options & RES_DEBUG) 286 printf("res_query failed\n"); 287 return NULL; 288 } 289 return getnetanswer(&buf, anslen, BYNAME); 290 } 291 292 void 293 _setnetdnsent(stayopen) 294 int stayopen; 295 { 296 if (stayopen) 297 _res.options |= RES_STAYOPEN | RES_USEVC; 298 } 299 300 void 301 _endnetdnsent() 302 { 303 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 304 _res_close(); 305 } 306