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[] = "$FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.13.2.4 2002/10/11 11:07:13 ume 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 <stdlib.h> 74 #include <netdb.h> 75 #include <resolv.h> 76 #include <ctype.h> 77 #include <string.h> 78 #include <unistd.h> 79 #include <syslog.h> 80 81 #include "res_config.h" 82 83 extern int h_errno; 84 85 #define BYADDR 0 86 #define BYNAME 1 87 #define MAXALIASES 35 88 89 #define MAXPACKET (64*1024) 90 91 typedef union { 92 HEADER hdr; 93 u_char buf[MAXPACKET]; 94 } querybuf; 95 96 typedef union { 97 long al; 98 char ac; 99 } align; 100 101 static struct netent * 102 getnetanswer(answer, anslen, net_i) 103 querybuf *answer; 104 int anslen; 105 int net_i; 106 { 107 108 register HEADER *hp; 109 register u_char *cp; 110 register int n; 111 u_char *eom; 112 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 113 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN]; 114 char *in, *st, *pauxt, *bp, **ap; 115 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 116 static struct netent net_entry; 117 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 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 return (NULL); 146 } 147 while (qdcount-- > 0) 148 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 149 ap = net_aliases; 150 *ap = NULL; 151 net_entry.n_aliases = net_aliases; 152 haveanswer = 0; 153 while (--ancount >= 0 && cp < eom) { 154 n = dn_expand(answer->buf, eom, cp, bp, buflen); 155 if ((n < 0) || !res_dnok(bp)) 156 break; 157 cp += n; 158 ans[0] = '\0'; 159 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 160 ans[sizeof(ans) - 1] = '\0'; 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) || !res_hnok(bp)) { 168 cp += n; 169 return (NULL); 170 } 171 cp += n; 172 *ap++ = bp; 173 n = strlen(bp) + 1; 174 bp += n; 175 buflen -= n; 176 net_entry.n_addrtype = 177 (class == C_IN) ? AF_INET : 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 break; 211 } 212 net_entry.n_aliases++; 213 return (&net_entry); 214 } 215 h_errno = TRY_AGAIN; 216 return (NULL); 217 } 218 219 struct netent * 220 _getnetbydnsaddr(net, net_type) 221 register unsigned 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 switch (nn) { 237 case 3: /* Class A */ 238 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 239 break; 240 case 2: /* Class B */ 241 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 242 break; 243 case 1: /* Class C */ 244 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 245 netbr[1]); 246 break; 247 case 0: /* Class D - E */ 248 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 249 netbr[1], netbr[0]); 250 break; 251 } 252 if ((buf = malloc(sizeof(*buf))) == NULL) { 253 h_errno = NETDB_INTERNAL; 254 return (NULL); 255 } 256 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 257 if (anslen < 0) { 258 free(buf); 259 #ifdef DEBUG 260 if (_res.options & RES_DEBUG) 261 printf("res_search failed\n"); 262 #endif 263 return (NULL); 264 } else if (anslen > sizeof(*buf)) { 265 free(buf); 266 #ifdef DEBUG 267 if (_res.options & RES_DEBUG) 268 printf("res_search static buffer too small\n"); 269 #endif 270 return (NULL); 271 } 272 net_entry = getnetanswer(buf, anslen, BYADDR); 273 free(buf); 274 if (net_entry) { 275 unsigned u_net = net; /* maybe net should be unsigned ? */ 276 277 /* Strip trailing zeros */ 278 while ((u_net & 0xff) == 0 && u_net != 0) 279 u_net >>= 8; 280 net_entry->n_net = u_net; 281 return (net_entry); 282 } 283 return (NULL); 284 } 285 286 struct netent * 287 _getnetbydnsname(net) 288 register const char *net; 289 { 290 int anslen; 291 querybuf *buf; 292 char qbuf[MAXDNAME]; 293 struct netent *net_entry; 294 295 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 296 h_errno = NETDB_INTERNAL; 297 return (NULL); 298 } 299 if ((buf = malloc(sizeof(*buf))) == NULL) { 300 h_errno = NETDB_INTERNAL; 301 return (NULL); 302 } 303 strncpy(qbuf, net, sizeof(qbuf) - 1); 304 qbuf[sizeof(qbuf) - 1] = '\0'; 305 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 306 if (anslen < 0) { 307 free(buf); 308 #ifdef DEBUG 309 if (_res.options & RES_DEBUG) 310 printf("res_search failed\n"); 311 #endif 312 return (NULL); 313 } else if (anslen > sizeof(*buf)) { 314 free(buf); 315 #ifdef DEBUG 316 if (_res.options & RES_DEBUG) 317 printf("res_search static buffer too small\n"); 318 #endif 319 return (NULL); 320 } 321 net_entry = getnetanswer(buf, anslen, BYNAME); 322 free(buf); 323 return net_entry; 324 } 325 326 void 327 _setnetdnsent(stayopen) 328 int stayopen; 329 { 330 if (stayopen) 331 _res.options |= RES_STAYOPEN | RES_USEVC; 332 } 333 334 void 335 _endnetdnsent() 336 { 337 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 338 res_close(); 339 } 340