#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
static const char rcsid[] = "$Id: res_query.c,v 1.2 2003/02/18 16:52:07 majka Exp $";
#endif
#ifndef __APPLE__
#include "port_before.h"
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "res_private.h"
#ifndef __APPLE__
#include "port_after.h"
#endif
#define DEBUG
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
int
res_nquery_2(res_state statp,
const char *name,
int class, int type,
u_char *answer,
int anslen,
struct sockaddr *from, int *fromlen)
{
u_char buf[MAXPACKET];
HEADER *hp = (HEADER *) answer;
int n;
u_int oflags;
oflags = statp->_flags;
again:
hp->rcode = ns_r_noerror;
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query(%s, %d, %d)\n", name, class, type);
#endif
n = res_nmkquery(statp, ns_o_query, name, class, type, NULL, 0, NULL,
buf, sizeof(buf));
#ifdef RES_USE_EDNS0
if (n > 0 && (statp->_flags & RES_F_EDNS0ERR) == 0 &&
(statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
n = res_nopt(statp, n, buf, sizeof(buf), anslen);
#endif
if (n <= 0) {
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query: mkquery failed\n");
#endif
__h_errno_set(statp, NO_RECOVERY);
return (n);
}
n = res_nsend_2(statp, buf, n, answer, anslen, from, fromlen);
if (n < 0) {
#ifdef RES_USE_EDNS0
if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0 &&
((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) {
statp->_flags |= RES_F_EDNS0ERR;
if (statp->options & RES_DEBUG)
printf(";; res_nquery: retry without EDNS0\n");
goto again;
}
#endif
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query: send error\n");
#endif
__h_errno_set(statp, TRY_AGAIN);
return (n);
}
if (hp->rcode != ns_r_noerror || ntohs(hp->ancount) == 0) {
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; rcode = %d, ancount=%d\n", hp->rcode,
ntohs(hp->ancount));
#endif
switch (hp->rcode) {
case ns_r_nxdomain:
__h_errno_set(statp, HOST_NOT_FOUND);
break;
case ns_r_servfail:
__h_errno_set(statp, TRY_AGAIN);
break;
case ns_r_noerror:
__h_errno_set(statp, NO_DATA);
break;
case ns_r_formerr:
case ns_r_notimpl:
case ns_r_refused:
default:
__h_errno_set(statp, NO_RECOVERY);
break;
}
return (-1);
}
return (n);
}
int
res_nquery(res_state statp, const char *name, int class, int type, u_char *answer, int anslen)
{
struct sockaddr_storage f;
int l;
l = sizeof(struct sockaddr_storage);
return res_nquery_2(statp, name, class, type, answer, anslen, (struct sockaddr *)&f, &l);
}
int
res_nquerydomain_2(res_state statp,
const char *name,
const char *domain,
int class, int type,
u_char *answer,
int anslen,
struct sockaddr *from, int *fromlen)
{
char nbuf[NS_MAXDNAME];
const char *longname = nbuf;
int n, d;
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
name, domain?domain:"<Nil>", class, type);
#endif
if (domain == NULL) {
n = strlen(name);
if (n >= NS_MAXDNAME) {
__h_errno_set(statp, NO_RECOVERY);
return (-1);
}
n--;
if (n >= 0 && name[n] == '.') {
strncpy(nbuf, name, n);
nbuf[n] = '\0';
} else
longname = name;
} else {
n = strlen(name);
d = strlen(domain);
if (n + d + 1 >= NS_MAXDNAME) {
__h_errno_set(statp, NO_RECOVERY);
return (-1);
}
sprintf(nbuf, "%s.%s", name, domain);
}
return (res_nquery_2(statp, longname, class, type, answer, anslen, from, fromlen));
}
int
res_nquerydomain(res_state statp, const char *name, const char *domain, int class, int type, u_char *answer, int anslen)
{
struct sockaddr_storage f;
int l;
l = sizeof(struct sockaddr_storage);
return res_nquerydomain_2(statp, name, domain, class, type, answer, anslen, (struct sockaddr *)&f, &l);
}
int
res_nsearch_2(res_state statp,
const char *name,
int class, int type,
u_char *answer,
int anslen,
struct sockaddr *from, int *fromlen)
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *) answer;
char tmp[NS_MAXDNAME];
u_int dots;
int trailing_dot, ret, saved_herrno;
int got_nodata = 0, got_servfail = 0, root_on_list = 0;
int tried_as_is = 0;
int searched = 0;
errno = 0;
__h_errno_set(statp, HOST_NOT_FOUND);
dots = 0;
for (cp = name; *cp != '\0'; cp++)
dots += (*cp == '.');
trailing_dot = 0;
if (cp > name && *--cp == '.')
trailing_dot++;
if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
return (res_nquery(statp, cp, class, type, answer, anslen));
saved_herrno = -1;
if (dots >= statp->ndots || trailing_dot) {
ret = res_nquerydomain(statp, name, NULL, class, type,
answer, anslen);
if (ret > 0 || trailing_dot)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
}
if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
(dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
int done = 0;
for (domain = (const char * const *)statp->dnsrch;
*domain && !done;
domain++) {
searched = 1;
if (domain[0][0] == '\0' ||
(domain[0][0] == '.' && domain[0][1] == '\0'))
root_on_list++;
ret = res_nquerydomain_2(statp, name, *domain,
class, type,
answer, anslen,
from, fromlen);
if (ret > 0)
return (ret);
if (errno == ECONNREFUSED) {
__h_errno_set(statp, TRY_AGAIN);
return (-1);
}
switch (statp->res_h_errno) {
case NO_DATA:
got_nodata++;
case HOST_NOT_FOUND:
break;
case TRY_AGAIN:
if (hp->rcode == ns_r_refused) {
got_servfail++;
break;
}
default:
done++;
}
if ((statp->options & RES_DNSRCH) == 0)
done++;
}
}
if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0) &&
!(tried_as_is || root_on_list)) {
ret = res_nquerydomain_2(statp, name, NULL, class, type,
answer, anslen,
from, fromlen);
if (ret > 0)
return (ret);
}
if (saved_herrno != -1)
__h_errno_set(statp, saved_herrno);
else if (got_nodata)
__h_errno_set(statp, NO_DATA);
else if (got_servfail)
__h_errno_set(statp, TRY_AGAIN);
return (-1);
}
int
res_nsearch(res_state statp, const char *name, int class, int type, u_char *answer, int anslen)
{
struct sockaddr_storage f;
int l;
l = sizeof(struct sockaddr_storage);
return res_nsearch_2(statp, name, class, type, answer, anslen, (struct sockaddr *)&f, &l);
}
const char *
res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
char *file, *cp1, *cp2;
char buf[BUFSIZ];
FILE *fp;
if (statp->options & RES_NOALIASES)
return (NULL);
file = getenv("HOSTALIASES");
if (file == NULL || (fp = fopen(file, "r")) == NULL)
return (NULL);
setbuf(fp, NULL);
buf[sizeof(buf) - 1] = '\0';
while (fgets(buf, sizeof(buf), fp)) {
for (cp1 = buf; *cp1 && !isspace((unsigned char)*cp1); ++cp1)
;
if (!*cp1)
break;
*cp1 = '\0';
if (ns_samename(buf, name) == 1) {
while (isspace((unsigned char)*++cp1))
;
if (!*cp1)
break;
for (cp2 = cp1 + 1; *cp2 &&
!isspace((unsigned char)*cp2); ++cp2)
;
*cp2 = '\0';
strncpy(dst, cp1, siz - 1);
dst[siz - 1] = '\0';
fclose(fp);
return (dst);
}
}
fclose(fp);
return (NULL);
}