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NetBSD/lib/libc/net/res_init.c

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/* $NetBSD: res_init.c,v 1.36 2000/08/09 14:41:03 itojun Exp $ */
/*-
* Copyright (c) 1985, 1989, 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--
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93";
static char rcsid[] = "Id: res_init.c,v 8.8 1997/06/01 20:34:37 vixie Exp ";
#else
__RCSID("$NetBSD: res_init.c,v 1.36 2000/08/09 14:41:03 itojun Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#if defined(_LIBC)
#include "namespace.h"
#endif
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <assert.h>
#include <ctype.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if defined(_LIBC) && defined(__weak_alias)
__weak_alias(res_init,_res_init)
#endif
static void res_setoptions __P((char *, char *));
static u_int32_t net_mask __P((struct in_addr));
static const char sort_mask[] = "/&";
#define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
/*
* Resolver state default settings
*/
/* #define __RES_IN_BSS */
#ifdef __RES_IN_BSS
struct __res_state _res;
#else
struct __res_state _res = {
RES_TIMEOUT, /* retransmition time interval */
4, /* number of times to retransmit */
RES_DEFAULT, /* options flags */
1, /* number of name servers */
};
#endif
#ifdef INET6
struct __res_state_ext _res_ext;
#endif /* INET6 */
/*
* Set up default settings. If the configuration file exist, the values
* there will have precedence. Otherwise, the server address is set to
* INADDR_ANY and the default domain name comes from the gethostname().
*
* An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
* rather than INADDR_ANY ("0.0.0.0") as the default name server address
* since it was noted that INADDR_ANY actually meant ``the first interface
* you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
* it had to be "up" in order for you to reach your own name server. It
* was later decided that since the recommended practice is to always
* install local static routes through 127.0.0.1 for all your network
* interfaces, that we could solve this problem without a code change.
*
* The configuration file should always be used, since it is the only way
* to specify a default domain. If you are running a server on your local
* machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
* in the configuration file.
*
* Return 0 if completes successfully, -1 on error
*/
int
res_init()
{
register FILE *fp;
register char *cp, **pp;
register int n;
char buf[MAXDNAME];
int nserv = 0; /* number of nameserver records read from file */
int haveenv = 0;
int havesearch = 0;
int nsort = 0;
char *net;
#ifndef RFC1535
int dots;
#endif
#ifdef __RES_IN_BSS
/*
* These three fields used to be statically initialized. This made
* it hard to use this code in a shared library. It is necessary,
* now that we're doing dynamic initialization here, that we preserve
* the old semantics: if an application modifies one of these three
* fields of _res before res_init() is called, res_init() will not
* alter them. Of course, if an application is setting them to
* _zero_ before calling res_init(), hoping to override what used
* to be the static default, we can't detect it and unexpected results
* will follow. Zero for any of these fields would make no sense,
* so one can safely assume that the applications were already getting
* unexpected results.
*
* _res.options is tricky since some apps were known to diddle the bits
* before res_init() was first called. We can't replicate that semantic
* with dynamic initialization (they may have turned bits off that are
* set in RES_DEFAULT). Our solution is to declare such applications
* "broken". They could fool us by setting RES_INIT but none do (yet).
*/
if (!_res.retrans)
_res.retrans = RES_TIMEOUT;
if (!_res.retry)
_res.retry = 4;
if (!(_res.options & RES_INIT))
_res.options = RES_DEFAULT;
/*
* This one used to initialize implicitly to zero, so unless the app
* has set it to something in particular, we can randomize it now.
*/
if (!_res.id)
_res.id = res_randomid();
#else
_res.id = res_randomid();
#endif
#ifdef USELOOPBACK
_res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
#else
_res.nsaddr.sin_addr.s_addr = INADDR_ANY;
#endif
_res.nsaddr.sin_family = AF_INET;
_res.nsaddr.sin_port = htons(NAMESERVER_PORT);
_res.nsaddr.sin_len = sizeof(struct sockaddr_in);
#ifdef INET6
if (sizeof(_res_ext.nsaddr) >= _res.nsaddr.sin_len)
memcpy(&_res_ext.nsaddr, &_res.nsaddr,
(size_t)_res.nsaddr.sin_len);
#endif
_res.nscount = 1;
_res.ndots = 1;
_res.pfcode = 0;
/* Allow user to override the local domain definition */
if ((cp = getenv("LOCALDOMAIN")) != NULL) {
(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
_res.defdname[sizeof(_res.defdname) - 1] = '\0';
if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
*cp = '\0';
haveenv++;
/*
* Set search list to be blank-separated strings
* from rest of env value. Permits users of LOCALDOMAIN
* to still have a search list, and anyone to set the
* one that they want to use as an individual (even more
* important now that the rfc1535 stuff restricts searches)
*/
cp = _res.defdname;
pp = _res.dnsrch;
*pp++ = cp;
for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
if (*cp == '\n') /* silly backwards compat */
break;
else if (*cp == ' ' || *cp == '\t') {
*cp = 0;
n = 1;
} else if (n) {
*pp++ = cp;
n = 0;
havesearch = 1;
}
}
/* null terminate last domain if there are excess */
while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
cp++;
*cp = '\0';
*pp++ = 0;
}
#define MATCH(line, name) \
(!strncmp(line, name, sizeof(name) - 1) && \
(line[sizeof(name) - 1] == ' ' || \
line[sizeof(name) - 1] == '\t'))
if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
/* read the config file */
while (fgets(buf, sizeof(buf), fp) != NULL) {
/* skip comments */
if ((*buf == ';') || (*buf == '#'))
continue;
/* read default domain name */
if (MATCH(buf, "domain")) {
if (haveenv) /* skip if have from environ */
continue;
cp = buf + sizeof("domain") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
_res.defdname[sizeof(_res.defdname) - 1] = '\0';
if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
*cp = '\0';
havesearch = 0;
continue;
}
/* lookup types; deprecated in favour of nsswitch.conf(5) */
if (MATCH(buf, "lookup"))
continue;
/* set search list */
if (MATCH(buf, "search")) {
if (haveenv) /* skip if have from environ */
continue;
cp = buf + sizeof("search") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
_res.defdname[sizeof(_res.defdname) - 1] = '\0';
if ((cp = strchr(_res.defdname, '\n')) != NULL)
*cp = '\0';
/*
* Set search list to be blank-separated strings
* on rest of line.
*/
cp = _res.defdname;
pp = _res.dnsrch;
*pp++ = cp;
for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
if (*cp == ' ' || *cp == '\t') {
*cp = 0;
n = 1;
} else if (n) {
*pp++ = cp;
n = 0;
}
}
/* null terminate last domain if there are excess */
while (*cp != '\0' && *cp != ' ' && *cp != '\t')
cp++;
*cp = '\0';
*pp++ = 0;
havesearch = 1;
continue;
}
/* read nameservers to query */
if (MATCH(buf, "nameserver") && nserv < MAXNS) {
struct addrinfo hints, *res;
char pbuf[NI_MAXSERV];
char *q;
#ifdef INET6
const size_t minsiz = sizeof(_res_ext.nsaddr_list[0]);
#else
const size_t minsiz = sizeof(_res.nsaddr_list[0]);
#endif
cp = buf + sizeof("nameserver") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
for (q = cp; *q; q++) {
if (isspace((u_char) *q)) {
*q = '\0';
break;
}
}
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_NUMERICHOST;
snprintf(pbuf, sizeof(pbuf), "%d", NAMESERVER_PORT);
res = NULL;
if (getaddrinfo(cp, pbuf, &hints, &res) == 0 &&
minsiz >= res->ai_addrlen) {
memset(&_res.nsaddr_list[nserv], 0,
sizeof(_res.nsaddr_list[nserv]));
#ifdef INET6
/*
* we copy the address to _res.nsaddr_list for
* backward compatibility only.
*/
#endif
if (sizeof(_res.nsaddr_list[nserv]) >= res->ai_addrlen) {
memcpy(&_res.nsaddr_list[nserv], res->ai_addr,
res->ai_addrlen);
}
#ifdef INET6
memset(&_res_ext.nsaddr_list[nserv], 0,
sizeof(_res_ext.nsaddr_list[nserv]));
memcpy(&_res_ext.nsaddr_list[nserv], res->ai_addr,
res->ai_addrlen);
#endif
nserv++;
}
if (res)
freeaddrinfo(res);
continue;
}
if (MATCH(buf, "sortlist")) {
struct in_addr a;
#ifdef INET6
struct in6_addr a6;
int m, i;
u_char *u;
#endif /* INET6 */
cp = buf + sizeof("sortlist") - 1;
while (nsort < MAXRESOLVSORT) {
while (*cp == ' ' || *cp == '\t')
cp++;
if (*cp == '\0' || *cp == '\n' || *cp == ';')
break;
net = cp;
while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
isascii(*cp) && !isspace((u_char) *cp))
cp++;
n = *cp;
*cp = 0;
if (inet_aton(net, &a)) {
_res.sort_list[nsort].addr = a;
if (ISSORTMASK(n)) {
*cp++ = n;
net = cp;
while (*cp && *cp != ';' &&
isascii(*cp) && !isspace((u_char) *cp))
cp++;
n = *cp;
*cp = 0;
if (inet_aton(net, &a)) {
_res.sort_list[nsort].mask = a.s_addr;
} else {
_res.sort_list[nsort].mask =
net_mask(_res.sort_list[nsort].addr);
}
} else {
_res.sort_list[nsort].mask =
net_mask(_res.sort_list[nsort].addr);
}
#ifdef INET6
_res_ext.sort_list[nsort].af = AF_INET;
_res_ext.sort_list[nsort].addr.ina =
_res.sort_list[nsort].addr;
_res_ext.sort_list[nsort].mask.ina.s_addr =
_res.sort_list[nsort].mask;
#endif /* INET6 */
nsort++;
}
#ifdef INET6
else if (inet_pton(AF_INET6, net, &a6) == 1) {
_res_ext.sort_list[nsort].af = AF_INET6;
_res_ext.sort_list[nsort].addr.in6a = a6;
u = (u_char *)(void *)
&_res_ext.sort_list[nsort].mask.in6a;
*cp++ = n;
net = cp;
while (*cp && *cp != ';' &&
isascii(*cp) && !isspace((u_char) *cp))
cp++;
m = n;
n = *cp;
*cp = 0;
switch (m) {
case '/':
m = atoi(net);
break;
case '&':
if (inet_pton(AF_INET6, net, u) == 1) {
m = -1;
break;
}
/*FALLTHRU*/
default:
m = sizeof(struct in6_addr) * NBBY;
break;
}
if (m >= 0) {
for (i = 0; i < sizeof(struct in6_addr); i++) {
if (m <= 0) {
*u = 0;
} else {
m -= NBBY;
*u = (u_char)~0;
if (m < 0)
*u <<= -m;
}
u++;
}
}
nsort++;
}
#endif /* INET6 */
*cp = n;
}
continue;
}
if (MATCH(buf, "options")) {
res_setoptions(buf + sizeof("options") - 1, "conf");
continue;
}
}
if (nserv > 1)
_res.nscount = nserv;
_res.nsort = nsort;
(void) fclose(fp);
}
if (_res.defdname[0] == 0) {
int rv;
rv = gethostname(buf, sizeof(_res.defdname));
_res.defdname[sizeof(_res.defdname) - 1] = '\0';
if (rv == 0 && (cp = strchr(buf, '.')))
(void)strncpy(_res.defdname, cp + 1, sizeof(_res.defdname) - 1);
}
/* find components of local domain that might be searched */
if (havesearch == 0) {
pp = _res.dnsrch;
*pp++ = _res.defdname;
*pp = NULL;
#ifndef RFC1535
dots = 0;
for (cp = _res.defdname; *cp; cp++)
dots += (*cp == '.');
cp = _res.defdname;
while (pp < _res.dnsrch + MAXDFLSRCH) {
if (dots < LOCALDOMAINPARTS)
break;
cp = strchr(cp, '.') + 1; /* we know there is one */
*pp++ = cp;
dots--;
}
*pp = NULL;
#ifdef DEBUG
if (_res.options & RES_DEBUG) {
printf(";; res_init()... default dnsrch list:\n");
for (pp = _res.dnsrch; *pp; pp++)
printf(";;\t%s\n", *pp);
printf(";;\t..END..\n");
}
#endif /* DEBUG */
#endif /* !RFC1535 */
}
if ((cp = getenv("RES_OPTIONS")) != NULL)
res_setoptions(cp, "env");
_res.options |= RES_INIT;
return (0);
}
/* ARGSUSED */
static void
res_setoptions(options, source)
char *options, *source;
{
char *cp = options;
int i;
_DIAGASSERT(options != NULL);
_DIAGASSERT(source != NULL);
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; res_setoptions(\"%s\", \"%s\")...\n",
options, source);
#endif
while (*cp) {
/* skip leading and inner runs of spaces */
while (*cp == ' ' || *cp == '\t')
cp++;
/* search for and process individual options */
if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
i = atoi(cp + sizeof("ndots:") - 1);
if (i <= RES_MAXNDOTS)
_res.ndots = i;
else
_res.ndots = RES_MAXNDOTS;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";;\tndots=%d\n", _res.ndots);
#endif
} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
#ifdef DEBUG
if (!(_res.options & RES_DEBUG)) {
printf(";; res_setoptions(\"%s\", \"%s\")..\n",
options, source);
_res.options |= RES_DEBUG;
}
printf(";;\tdebug\n");
#endif
} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
_res.options |= RES_USE_INET6;
}
#ifdef RES_USE_EDNS0
else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
_res.options |= RES_USE_EDNS0;
}
#endif
else {
/* XXX - print a warning here? */
}
/* skip to next run of spaces */
while (*cp && *cp != ' ' && *cp != '\t')
cp++;
}
}
/* XXX - should really support CIDR which means explicit masks always. */
static u_int32_t
net_mask(in) /* XXX - should really use system's version of this */
struct in_addr in;
{
register u_int32_t i = ntohl(in.s_addr);
if (IN_CLASSA(i))
return (htonl(IN_CLASSA_NET));
else if (IN_CLASSB(i))
return (htonl(IN_CLASSB_NET));
return (htonl(IN_CLASSC_NET));
}
u_int
res_randomid()
{
struct timeval now;
gettimeofday(&now, NULL);
return (u_int)(0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
}
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