getnetnamadr.c revision 1.7
1 /* $NetBSD: getnetnamadr.c,v 1.7 1998/12/05 13:17:55 pk Exp $ */ 2 3 /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 4 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 */ 10 /* 11 * Copyright (c) 1983, 1993 12 * The Regents of the University of California. All rights reserved. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #include <sys/cdefs.h> 44 #if defined(LIBC_SCCS) && !defined(lint) 45 #if 0 46 static char sccsid[] = "@(#)getnetbyaddr.c 8.1 (Berkeley) 6/4/93"; 47 static char sccsid_[] = "from getnetnamadr.c 1.4 (Coimbra) 93/06/03"; 48 static char rcsid[] = "Id: getnetnamadr.c,v 8.8 1997/06/01 20:34:37 vixie Exp "; 49 #else 50 __RCSID("$NetBSD: getnetnamadr.c,v 1.7 1998/12/05 13:17:55 pk Exp $"); 51 #endif 52 #endif /* LIBC_SCCS and not lint */ 53 54 #include "namespace.h" 55 #include <sys/types.h> 56 #include <sys/param.h> 57 #include <sys/socket.h> 58 #include <netinet/in.h> 59 #include <arpa/inet.h> 60 #include <arpa/nameser.h> 61 62 #include <stdio.h> 63 #include <netdb.h> 64 #include <resolv.h> 65 #include <ctype.h> 66 #include <errno.h> 67 #include <string.h> 68 69 #ifdef __weak_alias 70 __weak_alias(getnetbyaddr,_getnetbyaddr); 71 __weak_alias(getnetbyname,_getnetbyname); 72 #endif 73 74 extern int h_errno; 75 76 #if defined(mips) && defined(SYSTYPE_BSD43) 77 extern int errno; 78 #endif 79 80 /* XXX private header! */ 81 struct netent *__getnetbyaddr __P((unsigned long net, int type)); 82 struct netent *__getnetbyname __P((const char *name)); 83 84 #define BYADDR 0 85 #define BYNAME 1 86 #define MAXALIASES 35 87 88 #if PACKETSZ > 1024 89 #define MAXPACKET PACKETSZ 90 #else 91 #define MAXPACKET 1024 92 #endif 93 94 typedef union { 95 HEADER hdr; 96 u_char buf[MAXPACKET]; 97 } querybuf; 98 99 typedef union { 100 long al; 101 char ac; 102 } align; 103 104 static struct netent *getnetanswer __P((querybuf *, int, int)); 105 static struct netent * 106 getnetanswer(answer, anslen, net_i) 107 querybuf *answer; 108 int anslen; 109 int net_i; 110 { 111 112 register HEADER *hp; 113 register u_char *cp; 114 register int n; 115 u_char *eom; 116 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar; 117 char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap, 118 *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0; 119 static struct netent net_entry; 120 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 121 122 /* 123 * find first satisfactory answer 124 * 125 * answer --> +------------+ ( MESSAGE ) 126 * | Header | 127 * +------------+ 128 * | Question | the question for the name server 129 * +------------+ 130 * | Answer | RRs answering the question 131 * +------------+ 132 * | Authority | RRs pointing toward an authority 133 * | Additional | RRs holding additional information 134 * +------------+ 135 */ 136 eom = answer->buf + anslen; 137 hp = &answer->hdr; 138 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 139 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 140 bp = netbuf; 141 buflen = sizeof(netbuf); 142 cp = answer->buf + HFIXEDSZ; 143 if (!qdcount) { 144 if (hp->aa) 145 h_errno = HOST_NOT_FOUND; 146 else 147 h_errno = TRY_AGAIN; 148 return (NULL); 149 } 150 while (qdcount-- > 0) 151 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 152 ap = net_aliases; 153 *ap = NULL; 154 net_entry.n_aliases = net_aliases; 155 haveanswer = 0; 156 while (--ancount >= 0 && cp < eom) { 157 n = dn_expand(answer->buf, eom, cp, bp, buflen); 158 if ((n < 0) || !res_dnok(bp)) 159 break; 160 cp += n; 161 ans[0] = '\0'; 162 (void)strcpy(&ans[0], bp); 163 GETSHORT(type, cp); 164 GETSHORT(class, cp); 165 cp += INT32SZ; /* TTL */ 166 GETSHORT(n, cp); 167 if (class == C_IN && type == T_PTR) { 168 n = dn_expand(answer->buf, eom, cp, bp, buflen); 169 if ((n < 0) || !res_hnok(bp)) { 170 cp += n; 171 return (NULL); 172 } 173 cp += n; 174 *ap++ = bp; 175 bp += strlen(bp) + 1; 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 (size_t)((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 getnetbyaddr(net, net_type) 221 register u_long net; 222 register int net_type; 223 { 224 unsigned int netbr[4]; 225 int nn, anslen, i; 226 querybuf buf; 227 char qbuf[MAXDNAME]; 228 unsigned long net2; 229 struct netent *net_entry; 230 char lookups[MAXDNSLUS]; 231 232 if (net_type != AF_INET) 233 return (__getnetbyaddr(net, net_type)); 234 235 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 236 h_errno = NETDB_INTERNAL; 237 return (NULL); 238 } 239 240 memcpy(lookups, _res.lookups, sizeof(lookups)); 241 if (lookups[0] == '\0') 242 strncpy(lookups, "bf", sizeof(lookups)); 243 244 net_entry = NULL; 245 for (i = 0; i < MAXDNSLUS && net_entry == NULL && lookups[i]; i++) { 246 switch (lookups[i]) { 247 case 'b': 248 for (nn = 4, net2 = net; net2; net2 >>= 8) 249 netbr[--nn] = (unsigned int)(net2 & 0xff); 250 switch (nn) { 251 default: 252 return (NULL); 253 case 3: /* Class A */ 254 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", 255 netbr[3]); 256 break; 257 case 2: /* Class B */ 258 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", 259 netbr[3], netbr[2]); 260 break; 261 case 1: /* Class C */ 262 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", 263 netbr[3], netbr[2], netbr[1]); 264 break; 265 case 0: /* Class D - E */ 266 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 267 netbr[3], netbr[2], netbr[1], netbr[0]); 268 break; 269 } 270 anslen = res_query(qbuf, C_IN, T_PTR, 271 (u_char *)(void *)&buf, sizeof(buf)); 272 if (anslen < 0) { 273 #ifdef DEBUG 274 if (_res.options & RES_DEBUG) 275 printf("res_query failed\n"); 276 #endif 277 break; 278 } 279 net_entry = getnetanswer(&buf, anslen, BYADDR); 280 if (net_entry) { 281 /* maybe net should be unsigned? */ 282 unsigned long u_net = net; 283 284 /* Strip trailing zeros */ 285 while ((u_net & 0xff) == 0 && u_net != 0) 286 u_net >>= 8; 287 net_entry->n_net = u_net; 288 break; 289 } 290 break; 291 292 case 'f': 293 net_entry = __getnetbyaddr(net, net_type); 294 break; 295 } 296 } 297 298 return (net_entry); 299 } 300 301 struct netent * 302 getnetbyname(net) 303 register const char *net; 304 { 305 int anslen, i; 306 querybuf buf; 307 char qbuf[MAXDNAME]; 308 struct netent *net_entry; 309 char lookups[MAXDNSLUS]; 310 311 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 312 h_errno = NETDB_INTERNAL; 313 return (NULL); 314 } 315 316 memcpy(lookups, _res.lookups, sizeof(lookups)); 317 if (lookups[0] == '\0') 318 strncpy(lookups, "bf", sizeof(lookups)); 319 320 net_entry = NULL; 321 for (i = 0; i < MAXDNSLUS && net_entry == NULL && lookups[i]; i++) { 322 switch (lookups[i]) { 323 case 'b': 324 strcpy(&qbuf[0], net); 325 anslen = res_search(qbuf, C_IN, T_PTR, 326 (u_char *)(void *)&buf, sizeof(buf)); 327 if (anslen < 0) { 328 #ifdef DEBUG 329 if (_res.options & RES_DEBUG) 330 printf("res_query failed\n"); 331 #endif 332 break; 333 } 334 net_entry = getnetanswer(&buf, anslen, BYNAME); 335 break; 336 337 case 'f': 338 net_entry = __getnetbyname(net); 339 break; 340 } 341 } 342 343 return (net_entry); 344 } 345
Indexes created Tue Sep 30 17:09:57 GMT 2025