freebsd-dev/lib/libc/net/getnetbydns.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

468 lines
12 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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("$FreeBSD$");
#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 "netdb_private.h"
#include "res_config.h"
#define BYADDR 0
#define BYNAME 1
#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 int
getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne,
struct netent_data *ned, res_state statp)
{
HEADER *hp;
u_char *cp;
int n;
u_char *eom;
int type, class, ancount, qdcount, haveanswer;
char aux[MAXHOSTNAMELEN];
char ans[MAXHOSTNAMELEN];
char *in, *bp, *ep, **ap;
/*
* 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 = ned->netbuf;
ep = ned->netbuf + sizeof(ned->netbuf);
cp = answer->buf + HFIXEDSZ;
if (!qdcount) {
if (hp->aa)
RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
else
RES_SET_H_ERRNO(statp, TRY_AGAIN);
return (-1);
}
while (qdcount-- > 0)
cp += __dn_skipname(cp, eom) + QFIXEDSZ;
ap = ned->net_aliases;
*ap = NULL;
ne->n_aliases = ned->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 (-1);
}
cp += n;
*ap++ = bp;
n = strlen(bp) + 1;
bp += n;
ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
haveanswer++;
}
}
if (haveanswer) {
*ap = NULL;
switch (net_i) {
case BYADDR:
ne->n_name = *ne->n_aliases;
ne->n_net = 0L;
break;
case BYNAME:
in = *ne->n_aliases;
n = strlen(ans) + 1;
if (ep - bp < n) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
errno = ENOBUFS;
return (-1);
}
strlcpy(bp, ans, ep - bp);
ne->n_name = bp;
if (strlen(in) + 1 > sizeof(aux)) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
errno = ENOBUFS;
return (-1);
}
ipreverse(in, aux);
ne->n_net = inet_network(aux);
break;
}
ne->n_aliases++;
return (0);
}
RES_SET_H_ERRNO(statp, TRY_AGAIN);
return (-1);
}
int
_dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
{
uint32_t net;
int net_type;
char *buffer;
size_t buflen;
int *errnop, *h_errnop;
struct netent *nptr, ne;
struct netent_data *ned;
unsigned int netbr[4];
int nn, anslen, error;
querybuf *buf;
char qbuf[MAXDNAME];
uint32_t net2;
res_state statp;
net = va_arg(ap, uint32_t);
net_type = va_arg(ap, int);
nptr = va_arg(ap, struct netent *);
buffer = va_arg(ap, char *);
buflen = va_arg(ap, size_t);
errnop = va_arg(ap, int *);
h_errnop = va_arg(ap, int *);
statp = __res_state();
if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
}
if ((ned = __netent_data_init()) == NULL) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
}
*((struct netent **)rval) = NULL;
if (net_type != AF_INET) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
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) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_NOTFOUND);
}
anslen = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
sizeof(*buf));
if (anslen < 0) {
free(buf);
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf("res_nsearch failed\n");
#endif
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
} else if (anslen > sizeof(*buf)) {
free(buf);
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf("res_nsearch static buffer too small\n");
#endif
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
}
error = getnetanswer(buf, anslen, BYADDR, &ne, ned, statp);
free(buf);
if (error == 0) {
/* Strip trailing zeros */
while ((net & 0xff) == 0 && net != 0)
net >>= 8;
ne.n_net = net;
if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
*errnop = errno;
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_RETURN);
}
*((struct netent **)rval) = nptr;
return (NS_SUCCESS);
}
*h_errnop = statp->res_h_errno;
return (NS_NOTFOUND);
}
int
_dns_getnetbyname(void *rval, void *cb_data, va_list ap)
{
const char *net;
char *buffer;
size_t buflen;
int *errnop, *h_errnop;
struct netent *nptr, ne;
struct netent_data *ned;
int anslen, error;
querybuf *buf;
char qbuf[MAXDNAME];
res_state statp;
net = va_arg(ap, const char *);
nptr = va_arg(ap, struct netent *);
buffer = va_arg(ap, char *);
buflen = va_arg(ap, size_t);
errnop = va_arg(ap, int *);
h_errnop = va_arg(ap, int *);
statp = __res_state();
if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
}
if ((ned = __netent_data_init()) == NULL) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_UNAVAIL);
}
if ((buf = malloc(sizeof(*buf))) == NULL) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_NOTFOUND);
}
*((struct netent **)rval) = NULL;
strncpy(qbuf, net, sizeof(qbuf) - 1);
qbuf[sizeof(qbuf) - 1] = '\0';
anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
sizeof(*buf));
if (anslen < 0) {
free(buf);
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf("res_nsearch failed\n");
#endif
return (NS_UNAVAIL);
} else if (anslen > sizeof(*buf)) {
free(buf);
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf("res_search static buffer too small\n");
#endif
return (NS_UNAVAIL);
}
error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp);
free(buf);
if (error != 0) {
*h_errnop = statp->res_h_errno;
return (NS_NOTFOUND);
}
if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
*errnop = errno;
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
*h_errnop = statp->res_h_errno;
return (NS_RETURN);
}
*((struct netent **)rval) = nptr;
return (NS_SUCCESS);
}
void
_setnetdnsent(int stayopen)
{
res_state statp;
statp = __res_state();
if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
return;
if (stayopen)
statp->options |= RES_STAYOPEN | RES_USEVC;
}
void
_endnetdnsent(void)
{
res_state statp;
statp = __res_state();
statp->options &= ~(RES_STAYOPEN | RES_USEVC);
res_nclose(statp);
}