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53 * @(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93
54 * $FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.13.2.4 2002/10/11 11:07:13 ume Exp $
55 * $DragonFly: src/lib/libcr/net/Attic/getnetbydns.c,v 1.2 2003/06/17 04:26:44 dillon Exp $
57 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
58 * Dep. Matematica Universidade de Coimbra, Portugal, Europe
60 * Permission to use, copy, modify, and distribute this software for any
61 * purpose with or without fee is hereby granted, provided that the above
62 * copyright notice and this permission notice appear in all copies.
65 #include <sys/param.h>
66 #include <sys/socket.h>
67 #include <netinet/in.h>
68 #include <arpa/inet.h>
69 #include <arpa/nameser.h>
80 #include "res_config.h"
88 #define MAXPACKET (64*1024)
92 u_char buf[MAXPACKET];
100 static struct netent *
101 getnetanswer(answer, anslen, net_i)
111 int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
112 char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN];
113 char *in, *st, *pauxt, *bp, **ap;
114 char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
115 static struct netent net_entry;
116 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
119 * find first satisfactory answer
121 * answer --> +------------+ ( MESSAGE )
124 * | Question | the question for the name server
126 * | Answer | RRs answering the question
128 * | Authority | RRs pointing toward an authority
129 * | Additional | RRs holding additional information
132 eom = answer->buf + anslen;
134 ancount = ntohs(hp->ancount); /* #/records in the answer section */
135 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
137 buflen = sizeof(netbuf);
138 cp = answer->buf + HFIXEDSZ;
141 h_errno = HOST_NOT_FOUND;
146 while (qdcount-- > 0)
147 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
150 net_entry.n_aliases = net_aliases;
152 while (--ancount >= 0 && cp < eom) {
153 n = dn_expand(answer->buf, eom, cp, bp, buflen);
154 if ((n < 0) || !res_dnok(bp))
158 (void)strncpy(&ans[0], bp, sizeof(ans) - 1);
159 ans[sizeof(ans) - 1] = '\0';
162 cp += INT32SZ; /* TTL */
164 if (class == C_IN && type == T_PTR) {
165 n = dn_expand(answer->buf, eom, cp, bp, buflen);
166 if ((n < 0) || !res_hnok(bp)) {
175 net_entry.n_addrtype =
176 (class == C_IN) ? AF_INET : AF_UNSPEC;
184 net_entry.n_name = *net_entry.n_aliases;
185 net_entry.n_net = 0L;
188 in = *net_entry.n_aliases;
189 net_entry.n_name = &ans[0];
191 for (i = 0; i < 4; i++) {
192 for (st = in, nchar = 0;
196 if (nchar != 1 || *in != '0' || flag) {
200 (i==0) ?nchar : nchar+1);
201 paux1[(i==0) ? nchar : nchar+1] = '\0';
203 paux2 = strcat(paux1, paux2);
208 net_entry.n_net = inet_network(paux2);
211 net_entry.n_aliases++;
219 _getnetbydnsaddr(net, net_type)
220 register unsigned long net;
221 register int net_type;
223 unsigned int netbr[4];
228 struct netent *net_entry;
230 if (net_type != AF_INET)
233 for (nn = 4, net2 = net; net2; net2 >>= 8)
234 netbr[--nn] = net2 & 0xff;
236 case 3: /* Class A */
237 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
239 case 2: /* Class B */
240 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
242 case 1: /* Class C */
243 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
246 case 0: /* Class D - E */
247 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
251 if ((buf = malloc(sizeof(*buf))) == NULL) {
252 h_errno = NETDB_INTERNAL;
255 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
259 if (_res.options & RES_DEBUG)
260 printf("res_search failed\n");
263 } else if (anslen > sizeof(*buf)) {
266 if (_res.options & RES_DEBUG)
267 printf("res_search static buffer too small\n");
271 net_entry = getnetanswer(buf, anslen, BYADDR);
274 unsigned u_net = net; /* maybe net should be unsigned ? */
276 /* Strip trailing zeros */
277 while ((u_net & 0xff) == 0 && u_net != 0)
279 net_entry->n_net = u_net;
286 _getnetbydnsname(net)
287 register const char *net;
292 struct netent *net_entry;
294 if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
295 h_errno = NETDB_INTERNAL;
298 if ((buf = malloc(sizeof(*buf))) == NULL) {
299 h_errno = NETDB_INTERNAL;
302 strncpy(qbuf, net, sizeof(qbuf) - 1);
303 qbuf[sizeof(qbuf) - 1] = '\0';
304 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
308 if (_res.options & RES_DEBUG)
309 printf("res_search failed\n");
312 } else if (anslen > sizeof(*buf)) {
315 if (_res.options & RES_DEBUG)
316 printf("res_search static buffer too small\n");
320 net_entry = getnetanswer(buf, anslen, BYNAME);
326 _setnetdnsent(stayopen)
330 _res.options |= RES_STAYOPEN | RES_USEVC;
336 _res.options &= ~(RES_STAYOPEN | RES_USEVC);