freebsd-dev/lib/libc/net/gethostbydns.c

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1994-09-25 02:12:49 +00:00
/*-
* 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--
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$Id: gethostbydns.c,v 1.2 1994/09/25 17:45:37 pst Exp $";
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#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <syslog.h>
#define BYADDR 0
#define BYNAME 1
#define MAXALIASES 35
#define MAXADDRS 35
#define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */
static const char AskedForGot[] =
"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
static char *h_addr_ptrs[MAXADDRS + 1];
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[8*1024];
static struct in_addr host_addr;
static FILE *hostf = NULL;
static char hostaddr[MAXADDRS];
static char *host_addrs[2];
static int stayopen = 0;
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
typedef union {
int32_t al;
char ac;
} align;
extern int h_errno;
#ifdef RESOLVSORT
static void
addrsort(ap, num)
char **ap;
int num;
{
int i, j;
char **p;
short aval[MAXADDRS];
int needsort = 0;
p = ap;
for (i = 0; i < num; i++, p++) {
for (j = 0 ; j < _res.nsort; j++)
if (_res.sort_list[j].addr.s_addr ==
(((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
break;
aval[i] = j;
if (needsort == 0 && i > 0 && j < aval[i-1])
needsort = i;
}
if (!needsort)
return;
while (needsort < num) {
for (j = needsort - 1; j >= 0; j--) {
if (aval[j] > aval[j+1]) {
char *hp;
i = aval[j];
aval[j] = aval[j+1];
aval[j+1] = i;
hp = ap[j];
ap[j] = ap[j+1];
ap[j+1] = hp;
} else
break;
}
needsort++;
}
}
#endif
static struct hostent *
gethostanswer(answer, anslen, qname, qclass, qtype)
const querybuf *answer;
int anslen;
const char *qname;
int qclass, qtype;
{
register const HEADER *hp;
register const u_char *cp;
register int n;
const u_char *eom;
char *bp, **ap, **hap;
int type, class, buflen, ancount, qdcount;
int haveanswer, had_error;
int toobig = 0;
char tbuf[MAXDNAME+1];
host.h_name = NULL;
eom = answer->buf + anslen;
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
bp = hostbuf;
buflen = sizeof hostbuf;
cp = answer->buf + HFIXEDSZ;
if (qdcount != 1) {
h_errno = NO_RECOVERY;
return (NULL);
}
if ((n = dn_expand(answer->buf, eom, cp, bp, buflen)) < 0) {
h_errno = NO_RECOVERY;
return (NULL);
}
cp += n + QFIXEDSZ;
if (qtype == T_A) {
/* res_send() has already verified that the query name is the
* same as the one we sent; this just gets the expanded name
* (i.e., with the succeeding search-domain tacked on).
*/
n = strlen(bp) + 1; /* for the \0 */
host.h_name = bp;
bp += n;
buflen -= n;
/* The qname can be abbreviated, but h_name is now absolute. */
qname = host.h_name;
}
ap = host_aliases;
*ap = NULL;
host.h_aliases = host_aliases;
hap = h_addr_ptrs;
*hap = NULL;
host.h_addr_list = h_addr_ptrs;
haveanswer = 0;
had_error = 0;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if (n < 0) {
had_error++;
continue;
}
cp += n; /* name */
type = _getshort(cp);
cp += INT16SZ; /* type */
class = _getshort(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = _getshort(cp);
cp += INT16SZ; /* len */
if (class != qclass) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if (qtype == T_A && type == T_CNAME) {
if (ap >= &host_aliases[MAXALIASES-1])
continue;
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if (n < 0) {
had_error++;
continue;
}
cp += n;
if (host.h_name && strcasecmp(host.h_name, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s\", got CNAME for \"%s\"",
host.h_name, bp);
continue; /* XXX - had_error++ ? */
}
/* Store alias. */
*ap++ = bp;
n = strlen(bp) + 1; /* for the \0 */
bp += n;
buflen -= n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > buflen) {
had_error++;
continue;
}
strcpy(bp, tbuf);
host.h_name = bp;
bp += n;
buflen -= n;
continue;
}
if (type != qtype) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for type %d(%s), got %d(%s)",
qtype, qname, type, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
switch (type) {
case T_PTR:
if (strcasecmp(qname, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, qname, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if (n < 0) {
had_error++;
break;
}
#if MULTI_PTRS_ARE_ALIASES
cp += n;
if (!haveanswer)
host.h_name = bp;
else if (ap < &host_aliases[MAXALIASES-1])
*ap++ = bp;
else
n = -1;
if (n != -1) {
n = strlen(bp) + 1; /* for the \0 */
bp += n;
buflen -= n;
}
break;
#else
host.h_name = bp;
return (&host);
#endif
case T_A:
if (strcasecmp(host.h_name, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, host.h_name, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
if (haveanswer) {
if (n != host.h_length) {
cp += n;
continue;
}
} else {
register int nn;
host.h_length = n;
host.h_addrtype = (class == C_IN)
? AF_INET
: AF_UNSPEC;
host.h_name = bp;
nn = strlen(bp) + 1; /* for the \0 */
bp += nn;
buflen -= nn;
}
bp += sizeof(align) - ((u_long)bp % sizeof(align));
if (bp + n >= &hostbuf[sizeof hostbuf]) {
if (_res.options & RES_DEBUG)
printf("size (%d) too big\n", n);
had_error++;
continue;
}
if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
if (_res.options & RES_DEBUG && !toobig++)
printf("Too many addresses (%d)\n",
MAXADDRS);
cp += n;
continue;
}
bcopy(cp, *hap++ = bp, n);
bp += n;
cp += n;
break;
default:
abort();
} /*switch*/
if (!had_error)
haveanswer++;
} /*while*/
if (haveanswer) {
*ap = NULL;
*hap = NULL;
# if defined(RESOLVSORT)
/*
* Note: we sort even if host can take only one address
* in its return structures - should give it the "best"
* address in that case, not some random one
*/
if (_res.nsort && haveanswer > 1 &&
qclass == C_IN && qtype == T_A)
addrsort(h_addr_ptrs, haveanswer);
# endif /*RESOLVSORT*/
if (!host.h_name) {
n = strlen(qname) + 1; /* for the \0 */
strcpy(bp, qname);
host.h_name = bp;
}
return (&host);
} else {
h_errno = TRY_AGAIN;
return (NULL);
}
}
struct hostent *
_gethostbydnsname(name)
const char *name;
{
querybuf buf;
register const char *cp;
int n;
/*
* disallow names consisting only of digits/dots, unless
* they end in a dot.
*/
if (isdigit(name[0]))
for (cp = name;; ++cp) {
if (!*cp) {
if (*--cp == '.')
break;
/*
* All-numeric, no dot at the end.
* Fake up a hostent as if we'd actually
* done a lookup.
*/
if (!inet_aton(name, &host_addr)) {
h_errno = HOST_NOT_FOUND;
return (NULL);
}
host.h_name = (char *)name;
host.h_aliases = host_aliases;
host_aliases[0] = NULL;
host.h_addrtype = AF_INET;
host.h_length = INT32SZ;
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = NULL;
host.h_addr_list = h_addr_ptrs;
return (&host);
}
if (!isdigit(*cp) && *cp != '.')
break;
}
if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
if (_res.options & RES_DEBUG)
printf("res_search failed\n");
return (NULL);
}
return (gethostanswer(&buf, n, name, C_IN, T_A));
}
struct hostent *
_gethostbydnsaddr(addr, len, type)
const char *addr;
int len, type;
{
int n;
querybuf buf;
register struct hostent *hp;
char qbuf[MAXDNAME+1];
int o_res_options = _res.options;
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if (type != AF_INET)
return (NULL);
(void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
((unsigned)addr[3] & 0xff),
((unsigned)addr[2] & 0xff),
((unsigned)addr[1] & 0xff),
((unsigned)addr[0] & 0xff));
_res.options |= RES_RECURSE;
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n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
_res.options = o_res_options;
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if (n < 0) {
if (_res.options & RES_DEBUG)
printf("res_query failed\n");
return (NULL);
}
if (!(hp = gethostanswer(&buf, n, qbuf, C_IN, T_PTR)))
return (NULL);
hp->h_addrtype = type;
hp->h_length = len;
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = NULL;
host_addr = *(struct in_addr *)addr;
#if BSD < 43 && !defined(h_addr) /* new-style hostent structure */
hp->h_addr = h_addr_ptrs[0];
#endif
return (hp);
}
void
_sethostdnsent(stayopen)
int stayopen;
{
if (stayopen)
_res.options |= RES_STAYOPEN | RES_USEVC;
}
void
_endhostdnsent()
{
_res.options &= ~(RES_STAYOPEN | RES_USEVC);
_res_close();
}