/*
* 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 created by SGI are Copyright (C) 2000 Silicon Graphics, Inc.
* 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 Silicon Graphics, Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDERS AND 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.
*/
#include "sm/generic.h"
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "sm/nameser.h"
#include <resolv.h>
#include <netdb.h>
#include <errno.h>
#include "st.h"
#define MAXPACKET 1024
#if !defined(NETDB_INTERNAL) && defined(h_NETDB_INTERNAL)
#define NETDB_INTERNAL h_NETDB_INTERNAL
#endif
/* New in Solaris 7 */
#ifdef ns_get16
#define _getshort(cp) ns_get16(cp)
#endif
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf_t;
static int parse_answer(querybuf_t *ans, int len, struct in_addr *addr)
{
char buf[MAXPACKET];
HEADER *ahp;
u_char *cp, *eoa;
int type, n;
ahp = &ans->hdr;
eoa = ans->buf + len;
cp = ans->buf + sizeof(HEADER);
while (ahp->qdcount > 0) {
ahp->qdcount--;
cp += dn_skipname(cp, eoa) + QFIXEDSZ;
}
while (ahp->ancount > 0 && cp < eoa) {
ahp->ancount--;
if ((n = dn_expand(ans->buf, eoa, cp, buf, sizeof(buf))) < 0)
break;
cp += n;
type = _getshort(cp);
cp += 8;
n = _getshort(cp);
cp += 2;
if (T_CNAME == type) {
cp += n;
continue;
}
memcpy(addr, cp, n);
return 0;
}
h_errno = TRY_AGAIN;
return -1;
}
static int query_domain(st_netfd_t nfd, const char *name, struct in_addr *addr,
st_utime_t timeout)
{
querybuf_t qbuf;
u_char *buf = qbuf.buf;
HEADER *hp = &qbuf.hdr;
int blen = sizeof(qbuf);
int i, len, id;
for (i = 0; i < _res.nscount; i++) {
len = res_mkquery(QUERY, name, C_IN, T_A, NULL, 0, NULL, buf, blen);
if (len <= 0) {
h_errno = NO_RECOVERY;
return -1;
}
id = hp->id;
if (st_sendto(nfd, buf, len, (struct sockaddr *)&(_res.nsaddr_list[i]),
sizeof(struct sockaddr), timeout) != len) {
h_errno = NETDB_INTERNAL;
/* EINTR means interrupt by other thread, NOT by a caught signal */
if (EINTR == errno)
return -1;
continue;
}
/* Wait for reply */
do {
len = st_recvfrom(nfd, buf, blen, NULL, NULL, timeout);
if (len <= 0)
break;
} while (id != hp->id);
if (len < HFIXEDSZ) {
h_errno = NETDB_INTERNAL;
if (len >= 0)
errno = EMSGSIZE;
else if (EINTR == errno) /* see the comment above */
return -1;
continue;
}
hp->ancount = ntohs(hp->ancount);
hp->qdcount = ntohs(hp->qdcount);
if ((hp->rcode != NOERROR) || (hp->ancount == 0)) {
switch (hp->rcode) {
case NXDOMAIN:
h_errno = HOST_NOT_FOUND;
break;
case SERVFAIL:
h_errno = TRY_AGAIN;
break;
case NOERROR:
h_errno = NO_DATA;
break;
case FORMERR:
case NOTIMP:
case REFUSED:
default:
h_errno = NO_RECOVERY;
}
continue;
}
if (parse_answer(&qbuf, len, addr) == 0)
return 0;
}
return -1;
}
#define CLOSE_AND_RETURN(ret) \
{ \
n = errno; \
st_netfd_close(nfd); \
errno = n; \
return (ret); \
}
int dns_getaddr(const char *host, struct in_addr *addr, st_utime_t timeout)
{
char name[MAXDNAME], **domain;
const char *cp;
int s, n, maxlen, dots;
int trailing_dot, tried_as_is;
st_netfd_t nfd;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return -1;
}
if (_res.options & RES_USEVC) {
h_errno = NETDB_INTERNAL;
errno = ENOSYS;
return -1;
}
if (!host || *host == '\0') {
h_errno = HOST_NOT_FOUND;
return -1;
}
/* Create UDP socket */
if ((s = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
h_errno = NETDB_INTERNAL;
return -1;
}
if ((nfd = st_netfd_open_socket(s)) == NULL) {
h_errno = NETDB_INTERNAL;
n = errno;
close(s);
errno = n;
return -1;
}
maxlen = sizeof(name) - 1;
n = 0;
dots = 0;
trailing_dot = 0;
tried_as_is = 0;
for (cp = host; *cp && n < maxlen; cp++) {
dots += (*cp == '.');
name[n++] = *cp;
}
if (name[n - 1] == '.')
trailing_dot = 1;
/*
* If there are dots in the name already, let's just give it a try
* 'as is'. The threshold can be set with the "ndots" option.
*/
if (dots >= _res.ndots) {
if (query_domain(nfd, host, addr, timeout) == 0)
CLOSE_AND_RETURN(0);
if (h_errno == NETDB_INTERNAL && errno == EINTR)
CLOSE_AND_RETURN(-1);
tried_as_is = 1;
}
/*
* We do at least one level of search if
* - there is no dot and RES_DEFNAME is set, or
* - there is at least one dot, there is no trailing dot,
* and RES_DNSRCH is set.
*/
if ((!dots && (_res.options & RES_DEFNAMES)) ||
(dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
name[n++] = '.';
for (domain = _res.dnsrch; *domain; domain++) {
strncpy(name + n, *domain, maxlen - n);
if (query_domain(nfd, name, addr, timeout) == 0)
CLOSE_AND_RETURN(0);
if (h_errno == NETDB_INTERNAL && errno == EINTR)
CLOSE_AND_RETURN(-1);
if (!(_res.options & RES_DNSRCH))
break;
}
}
/*
* If we have not already tried the name "as is", do that now.
* note that we do this regardless of how many dots were in the
* name or whether it ends with a dot.
*/
if (!tried_as_is) {
if (query_domain(nfd, host, addr, timeout) == 0)
CLOSE_AND_RETURN(0);
}
CLOSE_AND_RETURN(-1);
}
syntax highlighted by Code2HTML, v. 0.9.1