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 1.5 2005/11/13 02:04:47 swildner 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(querybuf *answer, int anslen, int net_i) 98 { 99 100 HEADER *hp; 101 u_char *cp; 102 int n; 103 u_char *eom; 104 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 105 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN]; 106 char *in, *st, *pauxt, *bp, **ap; 107 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 108 static struct netent net_entry; 109 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 110 111 /* 112 * find first satisfactory answer 113 * 114 * answer --> +------------+ ( MESSAGE ) 115 * | Header | 116 * +------------+ 117 * | Question | the question for the name server 118 * +------------+ 119 * | Answer | RRs answering the question 120 * +------------+ 121 * | Authority | RRs pointing toward an authority 122 * | Additional | RRs holding additional information 123 * +------------+ 124 */ 125 eom = answer->buf + anslen; 126 hp = &answer->hdr; 127 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 128 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 129 bp = netbuf; 130 buflen = sizeof(netbuf); 131 cp = answer->buf + HFIXEDSZ; 132 if (!qdcount) { 133 if (hp->aa) 134 h_errno = HOST_NOT_FOUND; 135 else 136 h_errno = TRY_AGAIN; 137 return (NULL); 138 } 139 while (qdcount-- > 0) 140 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 141 ap = net_aliases; 142 *ap = NULL; 143 net_entry.n_aliases = net_aliases; 144 haveanswer = 0; 145 while (--ancount >= 0 && cp < eom) { 146 n = dn_expand(answer->buf, eom, cp, bp, buflen); 147 if ((n < 0) || !res_dnok(bp)) 148 break; 149 cp += n; 150 ans[0] = '\0'; 151 strncpy(&ans[0], bp, sizeof(ans) - 1); 152 ans[sizeof(ans) - 1] = '\0'; 153 GETSHORT(type, cp); 154 GETSHORT(class, cp); 155 cp += INT32SZ; /* TTL */ 156 GETSHORT(n, cp); 157 if (class == C_IN && type == T_PTR) { 158 n = dn_expand(answer->buf, eom, cp, bp, buflen); 159 if ((n < 0) || !res_hnok(bp)) { 160 cp += n; 161 return (NULL); 162 } 163 cp += n; 164 *ap++ = bp; 165 n = strlen(bp) + 1; 166 bp += n; 167 buflen -= n; 168 net_entry.n_addrtype = 169 (class == C_IN) ? AF_INET : AF_UNSPEC; 170 haveanswer++; 171 } 172 } 173 if (haveanswer) { 174 *ap = NULL; 175 switch (net_i) { 176 case BYADDR: 177 net_entry.n_name = *net_entry.n_aliases; 178 net_entry.n_net = 0L; 179 break; 180 case BYNAME: 181 in = *net_entry.n_aliases; 182 net_entry.n_name = &ans[0]; 183 aux2[0] = '\0'; 184 for (i = 0; i < 4; i++) { 185 for (st = in, nchar = 0; 186 *st != '.'; 187 st++, nchar++) 188 ; 189 if (nchar != 1 || *in != '0' || flag) { 190 flag = 1; 191 strncpy(paux1, (i==0) ? in : in-1, 192 (i==0) ? nchar : nchar+1); 193 paux1[(i==0) ? nchar : nchar+1] = '\0'; 194 pauxt = paux2; 195 paux2 = strcat(paux1, paux2); 196 paux1 = pauxt; 197 } 198 in = ++st; 199 } 200 net_entry.n_net = inet_network(paux2); 201 break; 202 } 203 net_entry.n_aliases++; 204 return (&net_entry); 205 } 206 h_errno = TRY_AGAIN; 207 return (NULL); 208 } 209 210 struct netent * 211 _getnetbydnsaddr(unsigned long net, int net_type) 212 { 213 unsigned int netbr[4]; 214 int nn, anslen; 215 querybuf *buf; 216 char qbuf[MAXDNAME]; 217 unsigned long net2; 218 struct netent *net_entry; 219 220 if (net_type != AF_INET) 221 return (NULL); 222 223 for (nn = 4, net2 = net; net2; net2 >>= 8) 224 netbr[--nn] = net2 & 0xff; 225 switch (nn) { 226 case 3: /* Class A */ 227 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 228 break; 229 case 2: /* Class B */ 230 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 231 break; 232 case 1: /* Class C */ 233 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 234 netbr[1]); 235 break; 236 case 0: /* Class D - E */ 237 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 238 netbr[1], netbr[0]); 239 break; 240 } 241 if ((buf = malloc(sizeof(*buf))) == NULL) { 242 h_errno = NETDB_INTERNAL; 243 return (NULL); 244 } 245 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 246 if (anslen < 0) { 247 free(buf); 248 #ifdef DEBUG 249 if (_res.options & RES_DEBUG) 250 printf("res_search failed\n"); 251 #endif 252 return (NULL); 253 } else if (anslen > sizeof(*buf)) { 254 free(buf); 255 #ifdef DEBUG 256 if (_res.options & RES_DEBUG) 257 printf("res_search static buffer too small\n"); 258 #endif 259 return (NULL); 260 } 261 net_entry = getnetanswer(buf, anslen, BYADDR); 262 free(buf); 263 if (net_entry) { 264 unsigned u_net = net; /* maybe net should be unsigned ? */ 265 266 /* Strip trailing zeros */ 267 while ((u_net & 0xff) == 0 && u_net != 0) 268 u_net >>= 8; 269 net_entry->n_net = u_net; 270 return (net_entry); 271 } 272 return (NULL); 273 } 274 275 struct netent * 276 _getnetbydnsname(const char *net) 277 { 278 int anslen; 279 querybuf *buf; 280 char qbuf[MAXDNAME]; 281 struct netent *net_entry; 282 283 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 284 h_errno = NETDB_INTERNAL; 285 return (NULL); 286 } 287 if ((buf = malloc(sizeof(*buf))) == NULL) { 288 h_errno = NETDB_INTERNAL; 289 return (NULL); 290 } 291 strncpy(qbuf, net, sizeof(qbuf) - 1); 292 qbuf[sizeof(qbuf) - 1] = '\0'; 293 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 294 if (anslen < 0) { 295 free(buf); 296 #ifdef DEBUG 297 if (_res.options & RES_DEBUG) 298 printf("res_search failed\n"); 299 #endif 300 return (NULL); 301 } else if (anslen > sizeof(*buf)) { 302 free(buf); 303 #ifdef DEBUG 304 if (_res.options & RES_DEBUG) 305 printf("res_search static buffer too small\n"); 306 #endif 307 return (NULL); 308 } 309 net_entry = getnetanswer(buf, anslen, BYNAME); 310 free(buf); 311 return net_entry; 312 } 313 314 void 315 _setnetdnsent(int stayopen) 316 { 317 if (stayopen) 318 _res.options |= RES_STAYOPEN | RES_USEVC; 319 } 320 321 void 322 _endnetdnsent(void) 323 { 324 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 325 res_close(); 326 } 327