2 * Copyright (c) 1985, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
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25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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29 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
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
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34 * the name of Digital Equipment Corporation not be used in advertising or
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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 $
53 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
54 * Dep. Matematica Universidade de Coimbra, Portugal, Europe
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.
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>
78 #include "res_config.h"
86 #define MAXPACKET (64*1024)
90 u_char buf[MAXPACKET];
98 static struct netent *
99 getnetanswer(querybuf *answer, int anslen, int net_i)
106 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
107 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN];
108 char *in, *st, *pauxt, *bp, **ap;
109 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
110 static struct netent net_entry;
111 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
114 * find first satisfactory answer
116 * answer --> +------------+ ( MESSAGE )
119 * | Question | the question for the name server
121 * | Answer | RRs answering the question
123 * | Authority | RRs pointing toward an authority
124 * | Additional | RRs holding additional information
127 eom = answer->buf + anslen;
129 ancount = ntohs(hp->ancount); /* #/records in the answer section */
130 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
132 buflen = sizeof(netbuf);
133 cp = answer->buf + HFIXEDSZ;
136 h_errno = HOST_NOT_FOUND;
141 while (qdcount-- > 0)
142 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
145 net_entry.n_aliases = net_aliases;
147 while (--ancount >= 0 && cp < eom) {
148 n = dn_expand(answer->buf, eom, cp, bp, buflen);
149 if ((n < 0) || !res_dnok(bp))
153 strncpy(&ans[0], bp, sizeof(ans) - 1);
154 ans[sizeof(ans) - 1] = '\0';
157 cp += INT32SZ; /* TTL */
159 if (class == C_IN && type == T_PTR) {
160 n = dn_expand(answer->buf, eom, cp, bp, buflen);
161 if ((n < 0) || !res_hnok(bp)) {
170 net_entry.n_addrtype =
171 (class == C_IN) ? AF_INET : AF_UNSPEC;
179 net_entry.n_name = *net_entry.n_aliases;
180 net_entry.n_net = 0L;
183 in = *net_entry.n_aliases;
184 net_entry.n_name = &ans[0];
186 for (i = 0; i < 4; i++) {
187 for (st = in, nchar = 0;
191 if (nchar != 1 || *in != '0' || flag) {
193 strncpy(paux1, (i==0) ? in : in-1,
194 (i==0) ? nchar : nchar+1);
195 paux1[(i==0) ? nchar : nchar+1] = '\0';
197 paux2 = strcat(paux1, paux2);
202 net_entry.n_net = inet_network(paux2);
205 net_entry.n_aliases++;
213 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
215 unsigned int netbr[4];
216 int nn, anslen, net_type;
219 unsigned long net, net2;
220 struct netent *net_entry;
222 net = va_arg(ap, unsigned long);
223 net_type = va_arg(ap, int);
225 *(struct netent **)rval = NULL;
227 if (net_type != AF_INET)
230 for (nn = 4, net2 = net; net2; net2 >>= 8)
231 netbr[--nn] = net2 & 0xff;
233 case 3: /* Class A */
234 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
236 case 2: /* Class B */
237 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
239 case 1: /* Class C */
240 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
243 case 0: /* Class D - E */
244 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
248 if ((buf = malloc(sizeof(*buf))) == NULL) {
249 h_errno = NETDB_INTERNAL;
252 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
256 if (_res.options & RES_DEBUG)
257 printf("res_search failed\n");
260 } else if (anslen > sizeof(*buf)) {
263 if (_res.options & RES_DEBUG)
264 printf("res_search static buffer too small\n");
268 net_entry = getnetanswer(buf, anslen, BYADDR);
271 unsigned u_net = net; /* maybe net should be unsigned ? */
273 /* Strip trailing zeros */
274 while ((u_net & 0xff) == 0 && u_net != 0)
276 net_entry->n_net = u_net;
277 *(struct netent **)rval = net_entry;
284 _dns_getnetbyname(void *rval, void *cb_data, va_list ap)
290 struct netent *net_entry;
292 net = va_arg(ap, const char *);
294 *(struct netent**)rval = NULL;
296 if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
297 h_errno = NETDB_INTERNAL;
300 if ((buf = malloc(sizeof(*buf))) == NULL) {
301 h_errno = NETDB_INTERNAL;
304 strncpy(qbuf, net, sizeof(qbuf) - 1);
305 qbuf[sizeof(qbuf) - 1] = '\0';
306 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
310 if (_res.options & RES_DEBUG)
311 printf("res_search failed\n");
314 } else if (anslen > sizeof(*buf)) {
317 if (_res.options & RES_DEBUG)
318 printf("res_search static buffer too small\n");
322 *(struct netent**)rval = getnetanswer(buf, anslen, BYNAME);
324 return (*(struct netent**)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
328 _setnetdnsent(int stayopen)
331 _res.options |= RES_STAYOPEN | RES_USEVC;
337 _res.options &= ~(RES_STAYOPEN | RES_USEVC);