/*
* ++Copyright++ 1985, 1988, 1993
* -
* 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[] = "$Id$";
#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 <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <resolv.h>
#include <ctype.h>
#include <errno.h>
#include <syslog.h>
#include "res_hconf.h"
#ifndef LOG_AUTH
# define LOG_AUTH 0
#endif
#define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */
#if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
# include <string.h>
#else
# include "../conf/portability.h"
#endif
#if defined(USE_OPTIONS_H)
# include <../conf/options.h>
#endif
#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) sprintf x
#endif
#define MAXALIASES 35
#define MAXADDRS 35
#define MAXADDRBUFSIZE 8192
static const char AskedForGot[] =
"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
static char *h_addr_ptrs[MAXADDRS + 1];
static struct hostent *gethostbyname_ipv4 __P((const char *));
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[MAXADDRBUFSIZE];
static u_char host_addr[16]; /* IPv4 or IPv6 */
static FILE *hostf = NULL;
static int stayopen = 0;
static void map_v4v6_address __P((const char *src, char *dst));
static void map_v4v6_hostent __P((struct hostent *hp, char **bp, int *len));
#ifdef RESOLVSORT
static void addrsort __P((char **, int));
#endif
#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 DEBUG
static void
dprintf(msg, num)
char *msg;
int num;
{
if (_res.options & RES_DEBUG) {
int save = errno;
printf(msg, num);
errno = save;
}
}
#else
# define dprintf(msg, num) /*nada*/
#endif
static struct hostent *
getanswer(answer, anslen, qname, qtype)
const querybuf *answer;
int anslen;
const char *qname;
int 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];
const char *tname;
int (*name_ok) __P((const char *));
tname = qname;
host.h_name = NULL;
eom = answer->buf + anslen;
switch (qtype) {
case T_A:
case T_AAAA:
name_ok = res_hnok;
break;
case T_PTR:
name_ok = res_dnok;
break;
default:
return (NULL); /* XXX should be abort(); */
}
/*
* 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);
}
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if ((n < 0) || !(*name_ok)(bp)) {
h_errno = NO_RECOVERY;
return (NULL);
}
cp += n + QFIXEDSZ;
if (qtype == T_A || qtype == T_AAAA) {
/* 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) || !(*name_ok)(bp)) {
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 != C_IN) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
if (ap >= &host_aliases[MAXALIASES-1])
continue;
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if ((n < 0) || !(*name_ok)(tbuf)) {
had_error++;
continue;
}
cp += n;
/* 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 (qtype == T_PTR && type == T_CNAME) {
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if ((n < 0) || !res_hnok(tbuf)) {
had_error++;
continue;
}
cp += n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > buflen) {
had_error++;
continue;
}
strcpy(bp, tbuf);
tname = bp;
bp += n;
buflen -= n;
continue;
}
if (type != qtype) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
qname, p_class(C_IN), p_type(qtype),
p_type(type));
cp += n;
continue; /* XXX - had_error++ ? */
}
switch (type) {
case T_PTR:
if (strcasecmp(tname, 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) || !res_hnok(bp)) {
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;
if (_res.options & RES_USE_INET6) {
n = strlen(bp) + 1; /* for the \0 */
bp += n;
buflen -= n;
map_v4v6_hostent(&host, &bp, &buflen);
}
h_errno = NETDB_SUCCESS;
return (&host);
#endif
case T_A:
case T_AAAA:
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_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]) {
dprintf("size (%d) too big\n", n);
had_error++;
continue;
}
if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
if (!toobig++)
dprintf("Too many addresses (%d)\n",
MAXADDRS);
cp += n;
continue;
}
bcopy(cp, *hap++ = bp, n);
bp += n;
cp += n;
break;
default:
abort();
}
if (!had_error)
haveanswer++;
}
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 && qtype == T_A)
addrsort(h_addr_ptrs, haveanswer);
# endif /*RESOLVSORT*/
if (!host.h_name) {
n = strlen(qname) + 1; /* for the \0 */
if (n > buflen)
goto try_again;
strcpy(bp, qname);
host.h_name = bp;
bp += n;
buflen -= n;
}
if (_res.options & RES_USE_INET6)
map_v4v6_hostent(&host, &bp, &buflen);
h_errno = NETDB_SUCCESS;
return (&host);
}
try_again:
h_errno = TRY_AGAIN;
return (NULL);
}
struct hostent *
gethostbyname(name)
const char *name;
{
struct hostent *hp;
if (_res.options & RES_USE_INET6) {
hp = gethostbyname2(name, AF_INET6);
if (hp)
return (hp);
}
return (gethostbyname2(name, AF_INET));
}
struct hostent *
gethostbyname2(name, af)
const char *name;
int af;
{
querybuf buf;
register const char *cp;
char *bp;
int i, n, size, type, len;
extern struct hostent *_gethtbyname2();
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (NULL);
}
switch (af) {
case AF_INET:
size = INADDRSZ;
type = T_A;
break;
case AF_INET6:
size = IN6ADDRSZ;
type = T_AAAA;
break;
default:
h_errno = NETDB_INTERNAL;
errno = EAFNOSUPPORT;
return (NULL);
}
host.h_addrtype = af;
host.h_length = size;
/*
* if there aren't any dots, it could be a user-level alias.
* this is also done in res_query() since we are not the only
* function that looks up host names.
*/
if (!strchr(name, '.') && (cp = __hostalias(name)))
name = cp;
/*
* 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_pton(af, name, host_addr) <= 0) {
h_errno = HOST_NOT_FOUND;
return (NULL);
}
strncpy(hostbuf, name, MAXDNAME);
hostbuf[MAXDNAME] = '\0';
bp = hostbuf + MAXDNAME;
len = sizeof hostbuf - MAXDNAME;
host.h_name = hostbuf;
host.h_aliases = host_aliases;
host_aliases[0] = NULL;
h_addr_ptrs[0] = (char *)host_addr;
h_addr_ptrs[1] = NULL;
host.h_addr_list = h_addr_ptrs;
if (_res.options & RES_USE_INET6)
map_v4v6_hostent(&host, &bp, &len);
h_errno = NETDB_SUCCESS;
return (&host);
}
if (!isdigit(*cp) && *cp != '.')
break;
}
h_errno = HOST_NOT_FOUND;
for (i = 0; i < _res_hconf.num_services; ++i) {
struct hostent * hp;
char * cp = (char *) name;
if (_res_hconf.num_trimdomains > 0) {
size_t name_len = strlen(name);
cp = malloc(name_len + 1);
memcpy(cp, name, name_len + 1);
_res_hconf_trim_domain(cp);
}
hp = NULL;
switch (_res_hconf.service[i]) {
case SERVICE_BIND:
if ((n = res_search(cp, C_IN, type,
buf.buf, sizeof(buf))) < 0)
{
dprintf("res_search failed (%d)\n", n);
break;
}
hp = getanswer(&buf, n, cp, type);
break;
case SERVICE_HOSTS:
hp = _gethtbyname2(cp, af);
break;
#ifdef HAVE_NYS
case SERVICE_NIS:
hp = _getnishost(cp, "hosts.byname");
break;
#endif
default:
break;
}
if (cp != name)
free(cp);
if (hp) {
if ((_res_hconf.flags & HCONF_FLAG_REORDER)
&& hp->h_addr_list[0] && hp->h_addr_list[1])
_res_hconf_reorder_addrs(hp);
_res_hconf_trim_domains(hp);
return hp;
}
}
if (h_errno == NETDB_SUCCESS)
h_errno = HOST_NOT_FOUND;
return NULL;
}
struct hostent *
gethostbyaddr(addr, len, af)
const char *addr; /* XXX should have been def'd as u_char! */
int len, af;
{
const u_char *uaddr = (const u_char *)addr;
static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
int n, size;
querybuf buf;
register struct hostent *hp;
char qbuf[MAXDNAME+1], *qp;
register struct hostent *rhp;
char **haddr;
u_long old_options;
char hname2[MAXDNAME+1];
int i, old_num_trimdomains;
extern struct hostent *_gethtbyaddr();
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (NULL);
}
if (af == AF_INET6 && len == IN6ADDRSZ &&
(!bcmp(uaddr, mapped, sizeof mapped) ||
!bcmp(uaddr, tunnelled, sizeof tunnelled))) {
/* Unmap. */
addr += sizeof mapped;
uaddr += sizeof mapped;
af = AF_INET;
len = INADDRSZ;
}
switch (af) {
case AF_INET:
size = INADDRSZ;
break;
case AF_INET6:
size = IN6ADDRSZ;
break;
default:
errno = EAFNOSUPPORT;
h_errno = NETDB_INTERNAL;
return (NULL);
}
if (size != len) {
errno = EINVAL;
h_errno = NETDB_INTERNAL;
return (NULL);
}
h_errno = NETDB_SUCCESS;
for (i = 0; i < _res_hconf.num_services; ++i) {
hp = NULL;
switch (_res_hconf.service[i]) {
case SERVICE_BIND:
switch (af) {
case AF_INET:
(void) sprintf(qbuf,
"%u.%u.%u.%u.in-addr.arpa",
(uaddr[3] & 0xff),
(uaddr[2] & 0xff),
(uaddr[1] & 0xff),
(uaddr[0] & 0xff));
break;
case AF_INET6:
qp = qbuf;
for (n = IN6ADDRSZ - 1; n >= 0; n--) {
qp += SPRINTF((qp, "%x.%x.",
uaddr[n] & 0xf,
(uaddr[n] >> 4) & 0xf));
}
strcpy(qp, "ip6.int");
break;
default:
abort();
}
n = res_query(qbuf, C_IN, T_PTR,
(u_char *)buf.buf, sizeof buf.buf);
if (n < 0) {
dprintf("res_query failed (%d)\n", n);
break;
}
hp = getanswer(&buf, n, qbuf, T_PTR);
if (!hp)
break; /* h_errno was set by getanswer() */
if (af == AF_INET
&& (_res_hconf.flags & HCONF_FLAG_SPOOF)) {
/*
* Turn off search as the name should
* be absolute, 'localhost' should be
* matched by defnames
*/
strncpy(hname2, hp->h_name, MAXDNAME);
hname2[MAXDNAME] = '\0';
old_options = _res.options;
/*
* Also turn off domain trimming to prevent it
* from causing the name comparison to fail.
*/
old_num_trimdomains =
_res_hconf.num_trimdomains;
_res.options &= ~RES_DNSRCH;
_res.options |= RES_DEFNAMES;
rhp = gethostbyname(hname2);
_res.options = old_options;
/* There must be an A record and
the names must match. */
if (!rhp || strcmp(hname2, rhp->h_name)) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostbyaddr: No A record for"
" %s (verifying [%s])",
hname2,
inet_ntoa(*((struct in_addr *)
addr)));
h_errno = HOST_NOT_FOUND;
break;
}
for (haddr = rhp->h_addr_list; *haddr; haddr++)
if (!memcmp(*haddr, addr, INADDRSZ))
break;
if (!*haddr) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostbyaddr: A record of %s"
" != PTR record [%s]",
hname2,
inet_ntoa(*((struct in_addr *)
addr)));
h_errno = HOST_NOT_FOUND;
break;
}
}
hp->h_addrtype = af;
hp->h_length = len;
bcopy(addr, host_addr, len);
h_addr_ptrs[0] = (char *)host_addr;
h_addr_ptrs[1] = NULL;
if (af == AF_INET && (_res.options & RES_USE_INET6)) {
map_v4v6_address((char*)host_addr,
(char*)host_addr);
hp->h_addrtype = AF_INET6;
hp->h_length = IN6ADDRSZ;
}
h_errno = NETDB_SUCCESS;
break;
case SERVICE_HOSTS:
hp = _gethtbyaddr(addr, len, af);
break;
#ifdef HAVE_NYS
case SERVICE_NIS:
if (af == AF_INET) {
sprintf(qbuf, "%u.%u.%u.%u",
(unsigned)addr[0] & 0xff,
(unsigned)addr[1] & 0xff,
(unsigned)addr[2] & 0xff,
(unsigned)addr[3] & 0xff);
hp = _getnishost(qbuf, "hosts.byaddr");
}
break;
#endif
default:
break;
}
if (hp) {
_res_hconf_trim_domains(hp);
return hp;
}
}
if (h_errno == NETDB_SUCCESS)
h_errno = HOST_NOT_FOUND;
return NULL;
}
void
_sethtent(f)
int f;
{
if (!hostf)
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;
int af, len;
if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
h_errno = NETDB_INTERNAL;
return (NULL);
}
again:
if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
h_errno = HOST_NOT_FOUND;
return (NULL);
}
if (*p == '#')
goto again;
if (!(cp = strpbrk(p, "#\n")))
goto again;
*cp = '\0';
if (!(cp = strpbrk(p, " \t")))
goto again;
*cp++ = '\0';
if ((_res.options & RES_USE_INET6) &&
inet_pton(AF_INET6, p, host_addr) > 0) {
af = AF_INET6;
len = IN6ADDRSZ;
} else if (inet_pton(AF_INET, p, host_addr) > 0) {
if (_res.options & RES_USE_INET6) {
map_v4v6_address((char*)host_addr, (char*)host_addr);
af = AF_INET6;
len = IN6ADDRSZ;
} else {
af = AF_INET;
len = INADDRSZ;
}
} else {
goto again;
}
h_addr_ptrs[0] = (char *)host_addr;
h_addr_ptrs[1] = NULL;
host.h_addr_list = h_addr_ptrs;
host.h_length = len;
host.h_addrtype = af;
while (*cp == ' ' || *cp == '\t')
cp++;
host.h_name = cp;
q = host.h_aliases = host_aliases;
if (cp = strpbrk(cp, " \t"))
*cp++ = '\0';
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (q < &host_aliases[MAXALIASES - 1])
*q++ = cp;
if (cp = strpbrk(cp, " \t"))
*cp++ = '\0';
}
*q = NULL;
if (_res.options & RES_USE_INET6) {
char *bp = hostbuf;
int buflen = sizeof hostbuf;
map_v4v6_hostent(&host, &bp, &buflen);
}
h_errno = NETDB_SUCCESS;
return (&host);
}
struct hstorage {
char *name; /* canonical name */
char ** alp; /* address list pointer */
char * abp; /* address buffer pointer */
char * addr_list[MAXADDRS + 1]; /* address list storage */
char addr_buf[MAXADDRBUFSIZE]; /* addresses storage */
};
static void
append_addr (struct hstorage * hs, struct hostent *p)
{
if (hs->alp < hs->addr_list + MAXADDRS
&& hs->abp + p->h_length < hs->addr_buf + MAXADDRBUFSIZE)
{
hs->alp[0] = hs->abp;
hs->alp[1] = 0;
memcpy(hs->abp, p->h_addr_list[0], p->h_length);
hs->abp += p->h_length;
++hs->alp;
}
}
/*
* Lookup IP address and aliases for host NAME. If multiaddress mode
* is enabled, the entire /etc/hosts file is searched and the union of
* all addresses found for NAME is returned (this may be slow with
* large /etc/hosts files, but is convenient for smallish sites that
* don't want to go through the complexity of running named locally).
* If multiaddress mode is enabled, the address returned in
* h_addr_list[0] is one that is on the same net as one of the host's
* local addresses (if such an address exists). For compatibility
* with the BIND version of gethostbyname(), the alias field is empty
* unless the name being looked up is an alias itself. In the latter
* case, the name field contains the canonical name and the alias
* field the name that is being looked up. A difference from the BIND
* version is that this is true even if the alias applies only to one
* of the interfaces on the target host.o
*/
struct hostent *
_gethtbyname(name)
const char *name;
{
extern struct hostent *_gethtbyname2();
struct hostent *hp;
if (_res.options & RES_USE_INET6) {
hp = _gethtbyname2(name, AF_INET6);
if (hp)
return (hp);
}
return (_gethtbyname2(name, AF_INET));
}
struct hostent *
_gethtbyname2(name, af)
const char *name;
int af;
{
register struct hostent *p;
register char **cp;
_sethtent(0);
if (_res_hconf.flags & HCONF_FLAG_MULTI) {
/*
* More statics; not pretty, but it would require
* interface changes to make these functions
* reentrant.
*/
static char *aliases[2] = {0};
static struct hstorage self = {0}, target = {0};
static size_t self_name_size = 0; /* Allocated in self.name. */
static struct hostent ht;
int found;
if (aliases[0])
free (aliases[0]); /* Malloced in a prev call. */
aliases[0] = aliases[1] = 0;
/* Get current host name in a large enough buffer. */
do {
errno = 0;
if (self.name)
{
self_name_size += self_name_size;
self.name =
realloc (self.name, self_name_size);
} else {
self_name_size = 128; /* Initial guess */
self.name = malloc (self_name_size);
}
if (! self.name)
{
errno = ENOMEM;
return 0;
}
} while ((gethostname(self.name, self_name_size) == 0
&& !memchr (self.name, '\0', self_name_size))
|| errno == ENAMETOOLONG);
if (errno)
/* gethostname failed, abort. */
{
free (self.name);
self.name = 0;
}
self.alp = self.addr_list;
self.abp = self.addr_buf;
if (target.name)
free (target.name);
target.name = strdup (name);
target.alp = target.addr_list;
target.abp = target.addr_buf;
_sethtent(0);
while ((p = _gethtent()) != 0) {
found = 1;
if (p->h_addrtype != af)
continue;
if (strcasecmp(p->h_name, name) != 0) {
found = 0;
for (cp = p->h_aliases; *cp; ++cp)
if (strcasecmp(*cp, name) == 0) {
found = 1;
if (!aliases[0]) {
aliases[0] =
target.name;
target.name =
strdup (p->h_name);
}
break;
}
}
if (found) {
/* they better be all the same type and length! */
ht.h_addrtype = p->h_addrtype;
ht.h_length = p->h_length;
append_addr(&target, p);
/*
* If the current hostentry is for the target host, we don't
* check for the local host name. This nicely optimizes the
* case where NAME is a local name since address ordering
* doesn't matter in that case.
*/
continue;
}
found = 1;
if (strcasecmp(p->h_name, self.name) != 0) {
found = 0;
for (cp = p->h_aliases; *cp; ++cp)
if (strcasecmp(*cp, self.name) == 0) {
found = 1;
break;
}
}
if (found) {
append_addr(&self, p);
}
}
_endhtent();
if (target.alp == target.addr_list)
return NULL; /* found nothing */
ht.h_aliases = aliases;
ht.h_name = target.name;
ht.h_addr_list = target.addr_list;
/*
* XXX (davidm) Isn't this subsumed by REORDER???
*
* Finding the `best' address is necessarily address
* specific. For now, we do IPv4 addresses only.
*/
if (af == AF_INET) {
u_int32_t a1, a2, diff, mindiff = ~0;
int i, j, bestaddr = 0;
for (i = 0; self.addr_list[i]; ++i) {
for (j = 0; target.addr_list[j]; ++j) {
memcpy(&a1, self.addr_list[i], 4);
memcpy(&a2, target.addr_list[j], 4);
a1 = ntohl(a1);
a2 = ntohl(a2);
diff = a1 ^ a2;
if (diff < mindiff) {
bestaddr = j;
mindiff = diff;
}
}
}
if (bestaddr > 0) {
char * tmp;
tmp = target.addr_list[0];
target.addr_list[0] = target.addr_list[bestaddr];
target.addr_list[bestaddr] = tmp;
}
} else if (af == AF_INET6) {
/* XXX To do!!! */
}
ht.h_addr_list = target.addr_list;
return &ht;
} else {
_sethtent(0);
while (p = _gethtent()) {
if (p->h_addrtype != af)
continue;
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, af)
const char *addr;
int len, af;
{
register struct hostent *p;
_sethtent(0);
while (p = _gethtent())
if (p->h_addrtype == af && !bcmp(p->h_addr, addr, len))
break;
_endhtent();
return (p);
}
static void
map_v4v6_address(src, dst)
const char *src;
char *dst;
{
u_char *p = (u_char *)dst;
char tmp[INADDRSZ];
int i;
/* Stash a temporary copy so our caller can update in place. */
bcopy(src, tmp, INADDRSZ);
/* Mark this ipv6 addr as a mapped ipv4. */
for (i = 0; i < 10; i++)
*p++ = 0x00;
*p++ = 0xff;
*p++ = 0xff;
/* Retrieve the saved copy and we're done. */
bcopy(tmp, (void*)p, INADDRSZ);
}
static void
map_v4v6_hostent(hp, bpp, lenp)
struct hostent *hp;
char **bpp;
int *lenp;
{
char **ap;
if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
return;
hp->h_addrtype = AF_INET6;
hp->h_length = IN6ADDRSZ;
for (ap = hp->h_addr_list; *ap; ap++) {
int i = sizeof(align) - ((u_long)*bpp % sizeof(align));
if (*lenp < (i + IN6ADDRSZ)) {
/* Out of memory. Truncate address list here. XXX */
*ap = NULL;
return;
}
*bpp += i;
*lenp -= i;
map_v4v6_address(*ap, *bpp);
*ap = *bpp;
*bpp += IN6ADDRSZ;
*lenp -= IN6ADDRSZ;
}
}
#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 ; (unsigned)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
#if defined(BSD43_BSD43_NFS) || defined(sun)
/* some libc's out there are bound internally to these names (UMIPS) */
void
ht_sethostent(stayopen)
int stayopen;
{
_sethtent(stayopen);
}
void
ht_endhostent()
{
_endhtent();
}
struct hostent *
ht_gethostbyname(name)
char *name;
{
return (_gethtbyname(name));
}
struct hostent *
ht_gethostbyaddr(addr, len, af)
const char *addr;
int len, af;
{
return (_gethtbyaddr(addr, len, af));
}
struct hostent *
gethostent()
{
struct hostent * hp;
int i;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (NULL);
}
/*
* This doesn't look quite right. Shouldn't we read one
* service until it returns 0, then move on to the next
* service? If so, it requires adding some state and
* initializing that state in sethostent().
* (davidm@azstarnet.com)
*/
for (i = 0; i < _res_hconf.num_services; ++i) {
hp = NULL;
switch (_res_hconf.service[i]) {
case SERVICE_HOSTS:
hp = _gethtent ();
break;
#ifdef HAVE_NYS
case SERVICE_NIS:
hp = _getnishost (NULL, "hosts.byname");
break;
#endif
case SERVICE_BIND:
default:
break;
}
if (hp) {
if ((_res_hconf.flags & HCONF_FLAG_REORDER)
&& hp->h_addr_list[0] && hp->h_addr_list[1])
_res_hconf_reorder_addrs (hp);
return hp;
}
}
h_errno = HOST_NOT_FOUND;
return NULL;
}
void
dns_service()
{
return;
}
#undef dn_skipname
dn_skipname(comp_dn, eom)
const u_char *comp_dn, *eom;
{
return (__dn_skipname(comp_dn, eom));
}
#endif /*old-style libc with yp junk in it*/