4.4BSD/usr/src/lib/libc/net/gethostnamadr.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--
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$Id: gethnamaddr.c,v 4.9.1.1 1993/05/02 22:43:03 vixie Rel $";
#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>
#define MAXALIASES 35
#define MAXADDRS 35
static char *h_addr_ptrs[MAXADDRS + 1];
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[BUFSIZ+1];
static struct in_addr host_addr;
static FILE *hostf = NULL;
static char hostaddr[MAXADDRS];
static char *host_addrs[2];
static int stayopen = 0;
char *strpbrk();
#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;
static struct hostent *
getanswer(answer, anslen, iquery)
querybuf *answer;
int anslen;
int iquery;
{
register HEADER *hp;
register u_char *cp;
register int n;
u_char *eom;
char *bp, **ap;
int type, class, buflen, ancount, qdcount;
int haveanswer, getclass = C_ANY;
char **hap;
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 + sizeof(HEADER);
if (qdcount) {
if (iquery) {
if ((n = dn_expand((u_char *)answer->buf,
(u_char *)eom, (u_char *)cp, (u_char *)bp,
buflen)) < 0) {
h_errno = NO_RECOVERY;
return ((struct hostent *) NULL);
}
cp += n + QFIXEDSZ;
host.h_name = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
} else
cp += __dn_skipname(cp, eom) + QFIXEDSZ;
while (--qdcount > 0)
cp += __dn_skipname(cp, eom) + QFIXEDSZ;
} else if (iquery) {
if (hp->aa)
h_errno = HOST_NOT_FOUND;
else
h_errno = TRY_AGAIN;
return ((struct hostent *) NULL);
}
ap = host_aliases;
*ap = NULL;
host.h_aliases = host_aliases;
hap = h_addr_ptrs;
*hap = NULL;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = h_addr_ptrs;
#endif
haveanswer = 0;
while (--ancount >= 0 && cp < eom) {
if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom,
(u_char *)cp, (u_char *)bp, buflen)) < 0)
break;
cp += n;
type = _getshort(cp);
cp += sizeof(u_int16_t);
class = _getshort(cp);
cp += sizeof(u_int16_t) + sizeof(u_int32_t);
n = _getshort(cp);
cp += sizeof(u_int16_t);
if (type == T_CNAME) {
cp += n;
if (ap >= &host_aliases[MAXALIASES-1])
continue;
*ap++ = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
continue;
}
if (iquery && type == T_PTR) {
if ((n = dn_expand((u_char *)answer->buf,
(u_char *)eom, (u_char *)cp, (u_char *)bp,
buflen)) < 0)
break;
cp += n;
host.h_name = bp;
return(&host);
}
if (iquery || type != T_A) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("unexpected answer type %d, size %d\n",
type, n);
#endif
cp += n;
continue;
}
if (haveanswer) {
if (n != host.h_length) {
cp += n;
continue;
}
if (class != getclass) {
cp += n;
continue;
}
} else {
host.h_length = n;
getclass = class;
host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
if (!iquery) {
host.h_name = bp;
bp += strlen(bp) + 1;
}
}
bp += sizeof(align) - ((u_int32_t)bp % sizeof(align));
if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("size (%d) too big\n", n);
#endif
break;
}
bcopy(cp, *hap++ = bp, n);
bp +=n;
cp += n;
haveanswer++;
}
if (haveanswer) {
*ap = NULL;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
*hap = NULL;
#else
host.h_addr = h_addr_ptrs[0];
#endif
return (&host);
} else {
h_errno = TRY_AGAIN;
return ((struct hostent *) NULL);
}
}
struct hostent *
gethostbyname(name)
const char *name;
{
querybuf buf;
register const char *cp;
int n;
extern struct hostent *_gethtbyname();
/*
* 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((struct hostent *) NULL);
}
host.h_name = (char *)name;
host.h_aliases = host_aliases;
host_aliases[0] = NULL;
host.h_addrtype = AF_INET;
host.h_length = sizeof(u_int32_t);
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = (char *)0;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = h_addr_ptrs;
#else
host.h_addr = h_addr_ptrs[0];
#endif
return (&host);
}
if (!isdigit(*cp) && *cp != '.')
break;
}
if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_search failed\n");
#endif
if (errno == ECONNREFUSED)
return (_gethtbyname(name));
else
return ((struct hostent *) NULL);
}
return (getanswer(&buf, n, 0));
}
struct hostent *
gethostbyaddr(addr, len, type)
const char *addr;
int len, type;
{
int n;
querybuf buf;
register struct hostent *hp;
char qbuf[MAXDNAME];
extern struct hostent *_gethtbyaddr();
if (type != AF_INET)
return ((struct hostent *) 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));
n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf));
if (n < 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf("res_query failed\n");
#endif
if (errno == ECONNREFUSED)
return (_gethtbyaddr(addr, len, type));
return ((struct hostent *) NULL);
}
hp = getanswer(&buf, n, 1);
if (hp == NULL)
return ((struct hostent *) NULL);
hp->h_addrtype = type;
hp->h_length = len;
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = (char *)0;
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
_sethtent(f)
int f;
{
if (hostf == NULL)
hostf = fopen(_PATH_HOSTS, "r" );
else
rewind(hostf);
stayopen |= f;
}
void
_endhtent()
{
if (hostf && !stayopen) {
(void) fclose(hostf);
hostf = NULL;
}
}
struct hostent *
_gethtent()
{
char *p;
register char *cp, **q;
if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
return (NULL);
again:
if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
return (NULL);
if (*p == '#')
goto again;
cp = strpbrk(p, "#\n");
if (cp == NULL)
goto again;
*cp = '\0';
cp = strpbrk(p, " \t");
if (cp == NULL)
goto again;
*cp++ = '\0';
/* THIS STUFF IS INTERNET SPECIFIC */
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = host_addrs;
#endif
host.h_addr = hostaddr;
*((u_int32_t *)host.h_addr) = inet_addr(p);
host.h_length = sizeof (u_int32_t);
host.h_addrtype = AF_INET;
while (*cp == ' ' || *cp == '\t')
cp++;
host.h_name = cp;
q = host.h_aliases = host_aliases;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (q < &host_aliases[MAXALIASES - 1])
*q++ = cp;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
}
*q = NULL;
return (&host);
}
struct hostent *
_gethtbyname(name)
char *name;
{
register struct hostent *p;
register char **cp;
_sethtent(0);
while (p = _gethtent()) {
if (strcasecmp(p->h_name, name) == 0)
break;
for (cp = p->h_aliases; *cp != 0; cp++)
if (strcasecmp(*cp, name) == 0)
goto found;
}
found:
_endhtent();
return (p);
}
struct hostent *
_gethtbyaddr(addr, len, type)
const char *addr;
int len, type;
{
register struct hostent *p;
_sethtent(0);
while (p = _gethtent())
if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len))
break;
_endhtent();
return (p);
}