FreeBSD-5.3/lib/libc/net/getnetbydns.c
/*-
* Copyright (c) 1985, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* -
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
* -
* --Copyright--
*/
/* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
* Dep. Matematica Universidade de Coimbra, Portugal, Europe
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.28 2004/02/07 11:13:47 ru Exp $");
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <resolv.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <stdarg.h>
#include <nsswitch.h>
#include "res_config.h"
extern int h_errno;
#define BYADDR 0
#define BYNAME 1
#define MAXALIASES 35
#define MAXPACKET (64*1024)
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
typedef union {
long al;
char ac;
} align;
/*
* Reverse the order of first four dotted entries of in.
* Out must contain space for at least strlen(in) characters.
* The result does not include any leading 0s of in.
*/
static void
ipreverse(char *in, char *out)
{
char *pos[4];
int len[4];
char *p, *start;
int i = 0;
int leading = 1;
/* Fill-in element positions and lengths: pos[], len[]. */
start = p = in;
for (;;) {
if (*p == '.' || *p == '\0') {
/* Leading 0? */
if (leading && p - start == 1 && *start == '0')
len[i] = 0;
else {
len[i] = p - start;
leading = 0;
}
pos[i] = start;
start = p + 1;
i++;
}
if (i == 4)
break;
if (*p == 0) {
for (; i < 4; i++) {
pos[i] = p;
len[i] = 0;
}
break;
}
p++;
}
/* Copy the entries in reverse order */
p = out;
leading = 1;
for (i = 3; i >= 0; i--) {
memcpy(p, pos[i], len[i]);
if (len[i])
leading = 0;
p += len[i];
/* Need a . separator? */
if (!leading && i > 0 && len[i - 1])
*p++ = '.';
}
*p = '\0';
}
static struct netent *
getnetanswer(answer, anslen, net_i)
querybuf *answer;
int anslen;
int net_i;
{
HEADER *hp;
u_char *cp;
int n;
u_char *eom;
int type, class, ancount, qdcount, haveanswer;
char aux[MAXHOSTNAMELEN];
char *in, *bp, *ep, **ap;
static struct netent net_entry;
static char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
static char ans[MAXHOSTNAMELEN];
/*
* find first satisfactory answer
*
* answer --> +------------+ ( MESSAGE )
* | Header |
* +------------+
* | Question | the question for the name server
* +------------+
* | Answer | RRs answering the question
* +------------+
* | Authority | RRs pointing toward an authority
* | Additional | RRs holding additional information
* +------------+
*/
eom = answer->buf + anslen;
hp = &answer->hdr;
ancount = ntohs(hp->ancount); /* #/records in the answer section */
qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
bp = netbuf;
ep = netbuf + sizeof(netbuf);
cp = answer->buf + HFIXEDSZ;
if (!qdcount) {
if (hp->aa)
h_errno = HOST_NOT_FOUND;
else
h_errno = TRY_AGAIN;
return (NULL);
}
while (qdcount-- > 0)
cp += __dn_skipname(cp, eom) + QFIXEDSZ;
ap = net_aliases;
*ap = NULL;
net_entry.n_aliases = net_aliases;
haveanswer = 0;
while (--ancount >= 0 && cp < eom) {
n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
if ((n < 0) || !res_dnok(bp))
break;
cp += n;
ans[0] = '\0';
(void)strncpy(&ans[0], bp, sizeof(ans) - 1);
ans[sizeof(ans) - 1] = '\0';
GETSHORT(type, cp);
GETSHORT(class, cp);
cp += INT32SZ; /* TTL */
GETSHORT(n, cp);
if (class == C_IN && type == T_PTR) {
n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
if ((n < 0) || !res_hnok(bp)) {
cp += n;
return (NULL);
}
cp += n;
*ap++ = bp;
n = strlen(bp) + 1;
bp += n;
net_entry.n_addrtype =
(class == C_IN) ? AF_INET : AF_UNSPEC;
haveanswer++;
}
}
if (haveanswer) {
*ap = NULL;
switch (net_i) {
case BYADDR:
net_entry.n_name = *net_entry.n_aliases;
net_entry.n_net = 0L;
break;
case BYNAME:
in = *net_entry.n_aliases;
net_entry.n_name = &ans[0];
if (strlen(in) + 1 > sizeof(aux)) {
h_errno = NETDB_INTERNAL;
errno = ENOBUFS;
return (NULL);
}
ipreverse(in, aux);
net_entry.n_net = inet_network(aux);
break;
}
net_entry.n_aliases++;
return (&net_entry);
}
h_errno = TRY_AGAIN;
return (NULL);
}
int
_dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
{
unsigned long net;
int net_type;
unsigned int netbr[4];
int nn, anslen;
querybuf *buf;
char qbuf[MAXDNAME];
unsigned long net2;
struct netent *net_entry;
net = va_arg(ap, unsigned long);
net_type = va_arg(ap, int);
*(struct netent **)rval = NULL;
if (net_type != AF_INET)
return NS_UNAVAIL;
for (nn = 4, net2 = net; net2; net2 >>= 8)
netbr[--nn] = net2 & 0xff;
switch (nn) {
case 3: /* Class A */
sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
break;
case 2: /* Class B */
sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
break;
case 1: /* Class C */
sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
netbr[1]);
break;
case 0: /* Class D - E */
sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
netbr[1], netbr[0]);
break;
}
if ((buf = malloc(sizeof(*buf))) == NULL) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
if (anslen < 0) {
free(buf);
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search failed\n");
#endif
return NS_UNAVAIL;
} else if (anslen > sizeof(*buf)) {
free(buf);
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search static buffer too small\n");
#endif
return NS_UNAVAIL;
}
net_entry = getnetanswer(buf, anslen, BYADDR);
free(buf);
if (net_entry) {
unsigned u_net = net; /* maybe net should be unsigned ? */
/* Strip trailing zeros */
while ((u_net & 0xff) == 0 && u_net != 0)
u_net >>= 8;
net_entry->n_net = u_net;
*(struct netent **)rval = net_entry;
return NS_SUCCESS;
}
return NS_NOTFOUND;
}
int
_dns_getnetbyname(void *rval, void *cb_data, va_list ap)
{
const char *net;
int anslen;
querybuf *buf;
char qbuf[MAXDNAME];
net = va_arg(ap, const char *);
*(struct netent**)rval = NULL;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return NS_UNAVAIL;
}
if ((buf = malloc(sizeof(*buf))) == NULL) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
strncpy(qbuf, net, sizeof(qbuf) - 1);
qbuf[sizeof(qbuf) - 1] = '\0';
anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf));
if (anslen < 0) {
free(buf);
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search failed\n");
#endif
return NS_UNAVAIL;
} else if (anslen > sizeof(*buf)) {
free(buf);
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search static buffer too small\n");
#endif
return NS_UNAVAIL;
}
*(struct netent**)rval = getnetanswer(buf, anslen, BYNAME);
free(buf);
return (*(struct netent**)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
}
void
_setnetdnsent(stayopen)
int stayopen;
{
if (stayopen)
_res.options |= RES_STAYOPEN | RES_USEVC;
}
void
_endnetdnsent()
{
_res.options &= ~(RES_STAYOPEN | RES_USEVC);
res_close();
}