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 * @(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93 54 * $FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.13.2.4 2002/10/11 11:07:13 ume Exp $ 55 * $DragonFly: src/lib/libc/net/getnetbydns.c,v 1.3 2004/10/25 19:38:01 drhodus Exp $ 56 */ 57 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 58 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 59 * 60 * Permission to use, copy, modify, and distribute this software for any 61 * purpose with or without fee is hereby granted, provided that the above 62 * copyright notice and this permission notice appear in all copies. 63 */ 64 65 #include <sys/param.h> 66 #include <sys/socket.h> 67 #include <netinet/in.h> 68 #include <arpa/inet.h> 69 #include <arpa/nameser.h> 70 71 #include <stdio.h> 72 #include <stdlib.h> 73 #include <netdb.h> 74 #include <resolv.h> 75 #include <ctype.h> 76 #include <string.h> 77 #include <unistd.h> 78 #include <syslog.h> 79 80 #include "res_config.h" 81 82 extern int h_errno; 83 84 #define BYADDR 0 85 #define BYNAME 1 86 #define MAXALIASES 35 87 88 #define MAXPACKET (64*1024) 89 90 typedef union { 91 HEADER hdr; 92 u_char buf[MAXPACKET]; 93 } querybuf; 94 95 typedef union { 96 long al; 97 char ac; 98 } align; 99 100 static struct netent * 101 getnetanswer(answer, anslen, net_i) 102 querybuf *answer; 103 int anslen; 104 int net_i; 105 { 106 107 HEADER *hp; 108 u_char *cp; 109 int n; 110 u_char *eom; 111 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 112 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN]; 113 char *in, *st, *pauxt, *bp, **ap; 114 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 115 static struct netent net_entry; 116 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 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 return (NULL); 145 } 146 while (qdcount-- > 0) 147 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 148 ap = net_aliases; 149 *ap = NULL; 150 net_entry.n_aliases = net_aliases; 151 haveanswer = 0; 152 while (--ancount >= 0 && cp < eom) { 153 n = dn_expand(answer->buf, eom, cp, bp, buflen); 154 if ((n < 0) || !res_dnok(bp)) 155 break; 156 cp += n; 157 ans[0] = '\0'; 158 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 159 ans[sizeof(ans) - 1] = '\0'; 160 GETSHORT(type, cp); 161 GETSHORT(class, cp); 162 cp += INT32SZ; /* TTL */ 163 GETSHORT(n, cp); 164 if (class == C_IN && type == T_PTR) { 165 n = dn_expand(answer->buf, eom, cp, bp, buflen); 166 if ((n < 0) || !res_hnok(bp)) { 167 cp += n; 168 return (NULL); 169 } 170 cp += n; 171 *ap++ = bp; 172 n = strlen(bp) + 1; 173 bp += n; 174 buflen -= n; 175 net_entry.n_addrtype = 176 (class == C_IN) ? AF_INET : 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 break; 210 } 211 net_entry.n_aliases++; 212 return (&net_entry); 213 } 214 h_errno = TRY_AGAIN; 215 return (NULL); 216 } 217 218 struct netent * 219 _getnetbydnsaddr(net, net_type) 220 unsigned long net; 221 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 switch (nn) { 236 case 3: /* Class A */ 237 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 238 break; 239 case 2: /* Class B */ 240 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 241 break; 242 case 1: /* Class C */ 243 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 244 netbr[1]); 245 break; 246 case 0: /* Class D - E */ 247 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 248 netbr[1], netbr[0]); 249 break; 250 } 251 if ((buf = malloc(sizeof(*buf))) == NULL) { 252 h_errno = NETDB_INTERNAL; 253 return (NULL); 254 } 255 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 256 if (anslen < 0) { 257 free(buf); 258 #ifdef DEBUG 259 if (_res.options & RES_DEBUG) 260 printf("res_search failed\n"); 261 #endif 262 return (NULL); 263 } else if (anslen > sizeof(*buf)) { 264 free(buf); 265 #ifdef DEBUG 266 if (_res.options & RES_DEBUG) 267 printf("res_search static buffer too small\n"); 268 #endif 269 return (NULL); 270 } 271 net_entry = getnetanswer(buf, anslen, BYADDR); 272 free(buf); 273 if (net_entry) { 274 unsigned u_net = net; /* maybe net should be unsigned ? */ 275 276 /* Strip trailing zeros */ 277 while ((u_net & 0xff) == 0 && u_net != 0) 278 u_net >>= 8; 279 net_entry->n_net = u_net; 280 return (net_entry); 281 } 282 return (NULL); 283 } 284 285 struct netent * 286 _getnetbydnsname(net) 287 const char *net; 288 { 289 int anslen; 290 querybuf *buf; 291 char qbuf[MAXDNAME]; 292 struct netent *net_entry; 293 294 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 295 h_errno = NETDB_INTERNAL; 296 return (NULL); 297 } 298 if ((buf = malloc(sizeof(*buf))) == NULL) { 299 h_errno = NETDB_INTERNAL; 300 return (NULL); 301 } 302 strncpy(qbuf, net, sizeof(qbuf) - 1); 303 qbuf[sizeof(qbuf) - 1] = '\0'; 304 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 305 if (anslen < 0) { 306 free(buf); 307 #ifdef DEBUG 308 if (_res.options & RES_DEBUG) 309 printf("res_search failed\n"); 310 #endif 311 return (NULL); 312 } else if (anslen > sizeof(*buf)) { 313 free(buf); 314 #ifdef DEBUG 315 if (_res.options & RES_DEBUG) 316 printf("res_search static buffer too small\n"); 317 #endif 318 return (NULL); 319 } 320 net_entry = getnetanswer(buf, anslen, BYNAME); 321 free(buf); 322 return net_entry; 323 } 324 325 void 326 _setnetdnsent(stayopen) 327 int stayopen; 328 { 329 if (stayopen) 330 _res.options |= RES_STAYOPEN | RES_USEVC; 331 } 332 333 void 334 _endnetdnsent() 335 { 336 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 337 res_close(); 338 } 339