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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * - 29 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 30 * 31 * Permission to use, copy, modify, and distribute this software for any 32 * purpose with or without fee is hereby granted, provided that the above 33 * copyright notice and this permission notice appear in all copies, and that 34 * the name of Digital Equipment Corporation not be used in advertising or 35 * publicity pertaining to distribution of the document or software without 36 * specific, written prior permission. 37 * 38 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 39 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 40 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 41 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 42 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 43 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 44 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 45 * SOFTWARE. 46 * - 47 * --Copyright-- 48 * 49 * @(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93 50 * $FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.13.2.4 2002/10/11 11:07:13 ume Exp $ 51 * $DragonFly: src/lib/libc/net/getnetbydns.c,v 1.4 2005/09/19 09:34:53 asmodai Exp $ 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 #include <sys/param.h> 62 #include <sys/socket.h> 63 #include <netinet/in.h> 64 #include <arpa/inet.h> 65 #include <arpa/nameser.h> 66 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <netdb.h> 70 #include <resolv.h> 71 #include <ctype.h> 72 #include <string.h> 73 #include <unistd.h> 74 #include <syslog.h> 75 76 #include "res_config.h" 77 78 extern int h_errno; 79 80 #define BYADDR 0 81 #define BYNAME 1 82 #define MAXALIASES 35 83 84 #define MAXPACKET (64*1024) 85 86 typedef union { 87 HEADER hdr; 88 u_char buf[MAXPACKET]; 89 } querybuf; 90 91 typedef union { 92 long al; 93 char ac; 94 } align; 95 96 static struct netent * 97 getnetanswer(answer, anslen, net_i) 98 querybuf *answer; 99 int anslen; 100 int net_i; 101 { 102 103 HEADER *hp; 104 u_char *cp; 105 int n; 106 u_char *eom; 107 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 108 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN]; 109 char *in, *st, *pauxt, *bp, **ap; 110 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 111 static struct netent net_entry; 112 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 113 114 /* 115 * find first satisfactory answer 116 * 117 * answer --> +------------+ ( MESSAGE ) 118 * | Header | 119 * +------------+ 120 * | Question | the question for the name server 121 * +------------+ 122 * | Answer | RRs answering the question 123 * +------------+ 124 * | Authority | RRs pointing toward an authority 125 * | Additional | RRs holding additional information 126 * +------------+ 127 */ 128 eom = answer->buf + anslen; 129 hp = &answer->hdr; 130 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 131 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 132 bp = netbuf; 133 buflen = sizeof(netbuf); 134 cp = answer->buf + HFIXEDSZ; 135 if (!qdcount) { 136 if (hp->aa) 137 h_errno = HOST_NOT_FOUND; 138 else 139 h_errno = TRY_AGAIN; 140 return (NULL); 141 } 142 while (qdcount-- > 0) 143 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 144 ap = net_aliases; 145 *ap = NULL; 146 net_entry.n_aliases = net_aliases; 147 haveanswer = 0; 148 while (--ancount >= 0 && cp < eom) { 149 n = dn_expand(answer->buf, eom, cp, bp, buflen); 150 if ((n < 0) || !res_dnok(bp)) 151 break; 152 cp += n; 153 ans[0] = '\0'; 154 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 155 ans[sizeof(ans) - 1] = '\0'; 156 GETSHORT(type, cp); 157 GETSHORT(class, cp); 158 cp += INT32SZ; /* TTL */ 159 GETSHORT(n, cp); 160 if (class == C_IN && type == T_PTR) { 161 n = dn_expand(answer->buf, eom, cp, bp, buflen); 162 if ((n < 0) || !res_hnok(bp)) { 163 cp += n; 164 return (NULL); 165 } 166 cp += n; 167 *ap++ = bp; 168 n = strlen(bp) + 1; 169 bp += n; 170 buflen -= n; 171 net_entry.n_addrtype = 172 (class == C_IN) ? AF_INET : AF_UNSPEC; 173 haveanswer++; 174 } 175 } 176 if (haveanswer) { 177 *ap = NULL; 178 switch (net_i) { 179 case BYADDR: 180 net_entry.n_name = *net_entry.n_aliases; 181 net_entry.n_net = 0L; 182 break; 183 case BYNAME: 184 in = *net_entry.n_aliases; 185 net_entry.n_name = &ans[0]; 186 aux2[0] = '\0'; 187 for (i = 0; i < 4; i++) { 188 for (st = in, nchar = 0; 189 *st != '.'; 190 st++, nchar++) 191 ; 192 if (nchar != 1 || *in != '0' || flag) { 193 flag = 1; 194 (void)strncpy(paux1, 195 (i==0) ? in : in-1, 196 (i==0) ?nchar : nchar+1); 197 paux1[(i==0) ? nchar : nchar+1] = '\0'; 198 pauxt = paux2; 199 paux2 = strcat(paux1, paux2); 200 paux1 = pauxt; 201 } 202 in = ++st; 203 } 204 net_entry.n_net = inet_network(paux2); 205 break; 206 } 207 net_entry.n_aliases++; 208 return (&net_entry); 209 } 210 h_errno = TRY_AGAIN; 211 return (NULL); 212 } 213 214 struct netent * 215 _getnetbydnsaddr(net, net_type) 216 unsigned long net; 217 int net_type; 218 { 219 unsigned int netbr[4]; 220 int nn, anslen; 221 querybuf *buf; 222 char qbuf[MAXDNAME]; 223 unsigned long net2; 224 struct netent *net_entry; 225 226 if (net_type != AF_INET) 227 return (NULL); 228 229 for (nn = 4, net2 = net; net2; net2 >>= 8) 230 netbr[--nn] = net2 & 0xff; 231 switch (nn) { 232 case 3: /* Class A */ 233 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 234 break; 235 case 2: /* Class B */ 236 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 237 break; 238 case 1: /* Class C */ 239 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 240 netbr[1]); 241 break; 242 case 0: /* Class D - E */ 243 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 244 netbr[1], netbr[0]); 245 break; 246 } 247 if ((buf = malloc(sizeof(*buf))) == NULL) { 248 h_errno = NETDB_INTERNAL; 249 return (NULL); 250 } 251 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 252 if (anslen < 0) { 253 free(buf); 254 #ifdef DEBUG 255 if (_res.options & RES_DEBUG) 256 printf("res_search failed\n"); 257 #endif 258 return (NULL); 259 } else if (anslen > sizeof(*buf)) { 260 free(buf); 261 #ifdef DEBUG 262 if (_res.options & RES_DEBUG) 263 printf("res_search static buffer too small\n"); 264 #endif 265 return (NULL); 266 } 267 net_entry = getnetanswer(buf, anslen, BYADDR); 268 free(buf); 269 if (net_entry) { 270 unsigned u_net = net; /* maybe net should be unsigned ? */ 271 272 /* Strip trailing zeros */ 273 while ((u_net & 0xff) == 0 && u_net != 0) 274 u_net >>= 8; 275 net_entry->n_net = u_net; 276 return (net_entry); 277 } 278 return (NULL); 279 } 280 281 struct netent * 282 _getnetbydnsname(net) 283 const char *net; 284 { 285 int anslen; 286 querybuf *buf; 287 char qbuf[MAXDNAME]; 288 struct netent *net_entry; 289 290 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 291 h_errno = NETDB_INTERNAL; 292 return (NULL); 293 } 294 if ((buf = malloc(sizeof(*buf))) == NULL) { 295 h_errno = NETDB_INTERNAL; 296 return (NULL); 297 } 298 strncpy(qbuf, net, sizeof(qbuf) - 1); 299 qbuf[sizeof(qbuf) - 1] = '\0'; 300 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 301 if (anslen < 0) { 302 free(buf); 303 #ifdef DEBUG 304 if (_res.options & RES_DEBUG) 305 printf("res_search failed\n"); 306 #endif 307 return (NULL); 308 } else if (anslen > sizeof(*buf)) { 309 free(buf); 310 #ifdef DEBUG 311 if (_res.options & RES_DEBUG) 312 printf("res_search static buffer too small\n"); 313 #endif 314 return (NULL); 315 } 316 net_entry = getnetanswer(buf, anslen, BYNAME); 317 free(buf); 318 return net_entry; 319 } 320 321 void 322 _setnetdnsent(stayopen) 323 int stayopen; 324 { 325 if (stayopen) 326 _res.options |= RES_STAYOPEN | RES_USEVC; 327 } 328 329 void 330 _endnetdnsent() 331 { 332 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 333 res_close(); 334 } 335