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 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 54 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 55 * 56 * Permission to use, copy, modify, and distribute this software for any 57 * purpose with or without fee is hereby granted, provided that the above 58 * copyright notice and this permission notice appear in all copies. 59 */ 60 61 #if defined(LIBC_SCCS) && !defined(lint) 62 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 63 static char rcsid[] = "$Id: getnetbydns.c,v 1.6 1996/07/12 18:54:37 jkh Exp $"; 64 #endif /* LIBC_SCCS and not lint */ 65 66 #include <sys/param.h> 67 #include <sys/socket.h> 68 #include <netinet/in.h> 69 #include <arpa/inet.h> 70 #include <arpa/nameser.h> 71 72 #include <stdio.h> 73 #include <netdb.h> 74 #include <resolv.h> 75 #include <ctype.h> 76 #include <errno.h> 77 #include <string.h> 78 #include <unistd.h> 79 #include <syslog.h> 80 81 #include "res_config.h" 82 83 extern void _res_close __P((void)); 84 extern int h_errno; 85 86 #define BYADDR 0 87 #define BYNAME 1 88 #define MAXALIASES 35 89 90 #if PACKETSZ > 1024 91 #define MAXPACKET PACKETSZ 92 #else 93 #define MAXPACKET 1024 94 #endif 95 96 typedef union { 97 HEADER hdr; 98 u_char buf[MAXPACKET]; 99 } querybuf; 100 101 typedef union { 102 long al; 103 char ac; 104 } align; 105 106 static struct netent * 107 getnetanswer(answer, anslen, net_i) 108 querybuf *answer; 109 int anslen; 110 int net_i; 111 { 112 113 register HEADER *hp; 114 register u_char *cp; 115 register int n; 116 u_char *eom; 117 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 118 char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap, 119 *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 120 static struct netent net_entry; 121 static char *net_aliases[MAXALIASES], netbuf[BUFSIZ+1]; 122 123 /* 124 * find first satisfactory answer 125 * 126 * answer --> +------------+ ( MESSAGE ) 127 * | Header | 128 * +------------+ 129 * | Question | the question for the name server 130 * +------------+ 131 * | Answer | RRs answering the question 132 * +------------+ 133 * | Authority | RRs pointing toward an authority 134 * | Additional | RRs holding additional information 135 * +------------+ 136 */ 137 eom = answer->buf + anslen; 138 hp = &answer->hdr; 139 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 140 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 141 bp = netbuf; 142 buflen = sizeof(netbuf); 143 cp = answer->buf + HFIXEDSZ; 144 if (!qdcount) { 145 if (hp->aa) 146 h_errno = HOST_NOT_FOUND; 147 else 148 h_errno = TRY_AGAIN; 149 return (NULL); 150 } 151 while (qdcount-- > 0) 152 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 153 ap = net_aliases; 154 *ap = NULL; 155 net_entry.n_aliases = net_aliases; 156 haveanswer = 0; 157 while (--ancount >= 0 && cp < eom) { 158 n = dn_expand(answer->buf, eom, cp, bp, buflen); 159 if ((n < 0) || !res_dnok(bp)) 160 break; 161 cp += n; 162 ans[0] = '\0'; 163 (void)strcpy(&ans[0], bp); 164 GETSHORT(type, cp); 165 GETSHORT(class, cp); 166 cp += INT32SZ; /* TTL */ 167 GETSHORT(n, cp); 168 if (class == C_IN && type == T_PTR) { 169 n = dn_expand(answer->buf, eom, cp, bp, buflen); 170 if ((n < 0) || !res_hnok(bp)) { 171 cp += n; 172 return (NULL); 173 } 174 cp += n; 175 *ap++ = bp; 176 bp += strlen(bp) + 1; 177 net_entry.n_addrtype = 178 (class == C_IN) ? AF_INET : AF_UNSPEC; 179 haveanswer++; 180 } 181 } 182 if (haveanswer) { 183 *ap = NULL; 184 switch (net_i) { 185 case BYADDR: 186 net_entry.n_name = *net_entry.n_aliases; 187 net_entry.n_net = 0L; 188 break; 189 case BYNAME: 190 in = *net_entry.n_aliases; 191 net_entry.n_name = &ans[0]; 192 aux2[0] = '\0'; 193 for (i = 0; i < 4; i++) { 194 for (st = in, nchar = 0; 195 *st != '.'; 196 st++, nchar++) 197 ; 198 if (nchar != 1 || *in != '0' || flag) { 199 flag = 1; 200 (void)strncpy(paux1, 201 (i==0) ? in : in-1, 202 (i==0) ?nchar : nchar+1); 203 paux1[(i==0) ? nchar : nchar+1] = '\0'; 204 pauxt = paux2; 205 paux2 = strcat(paux1, paux2); 206 paux1 = pauxt; 207 } 208 in = ++st; 209 } 210 net_entry.n_net = inet_network(paux2); 211 break; 212 } 213 net_entry.n_aliases++; 214 return (&net_entry); 215 } 216 h_errno = TRY_AGAIN; 217 return (NULL); 218 } 219 220 struct netent * 221 _getnetbydnsaddr(net, net_type) 222 register unsigned long net; 223 register int net_type; 224 { 225 unsigned int netbr[4]; 226 int nn, anslen; 227 querybuf buf; 228 char qbuf[MAXDNAME]; 229 unsigned long net2; 230 struct netent *net_entry; 231 232 if (net_type != AF_INET) 233 return (NULL); 234 235 for (nn = 4, net2 = net; net2; net2 >>= 8) 236 netbr[--nn] = net2 & 0xff; 237 switch (nn) { 238 case 3: /* Class A */ 239 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 240 break; 241 case 2: /* Class B */ 242 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 243 break; 244 case 1: /* Class C */ 245 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 246 netbr[1]); 247 break; 248 case 0: /* Class D - E */ 249 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 250 netbr[1], netbr[0]); 251 break; 252 } 253 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); 254 if (anslen < 0) { 255 #ifdef DEBUG 256 if (_res.options & RES_DEBUG) 257 printf("res_query failed\n"); 258 #endif 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 net_entry->n_net = u_net; 269 return (net_entry); 270 } 271 return (NULL); 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 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 283 h_errno = NETDB_INTERNAL; 284 return (NULL); 285 } 286 strcpy(&qbuf[0], net); 287 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf)); 288 if (anslen < 0) { 289 #ifdef DEBUG 290 if (_res.options & RES_DEBUG) 291 printf("res_query failed\n"); 292 #endif 293 return (NULL); 294 } 295 return getnetanswer(&buf, anslen, BYNAME); 296 } 297 298 void 299 _setnetdnsent(stayopen) 300 int stayopen; 301 { 302 if (stayopen) 303 _res.options |= RES_STAYOPEN | RES_USEVC; 304 } 305 306 void 307 _endnetdnsent() 308 { 309 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 310 _res_close(); 311 } 312