source: rtems/cpukit/libnetworking/libc/res_init.c @ cb68253

#include <machine/rtems-bsd-user-space.h>

/*
 * 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.
 */

/*
 * Portions Copyright (c) 1996 by Internet Software Consortium.
 *
 * 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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM 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.
 */

#if HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#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 <ctype.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "res_config.h"

/*
 * RTEMS -- set up name servers from global variable
 */
#include <rtems/rtems_bsdnet_internal.h>
#include <rtems/bsdnet/servers.h>

static void res_setoptions(char *, char *);

#ifdef RESOLVSORT
static const char sort_mask[] = "/&";
#define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
static u_int32_t net_mask(struct in_addr);
#endif

#if !defined(isascii) /* XXX - could be a function */
# define isascii(c) (!(c & 0200))
#endif

/*
 * Resolver state default settings.
 */

struct __res_state _res
# if defined(__BIND_RES_TEXT)
        = { RES_TIMEOUT, }      /* Motorola, et al. */
# endif
        ;


/*
 * 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(void)
{
        FILE *fp;
        char *cp, **pp;
        int n;
        char buf[MAXDNAME];
        int nserv = 0;    /* number of nameserver records read from file */
        int haveenv = 0;
        int havesearch = 0;
#ifdef RESOLVSORT
        int nsort = 0;
        char *net;
#endif
#ifndef RFC1535
        int dots;
#endif

        /*
         * 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();

#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.nscount = 1;
        _res.ndots = 1;
        _res.pfcode = 0;

        /*
         * RTEMS -- Set up name servers
         */
        {
        int n = 0;
        while ((n < rtems_bsdnet_nameserver_count) && (nserv < MAXNS)) {
                _res.nsaddr_list[nserv].sin_addr = rtems_bsdnet_nameserver[n];
                _res.nsaddr_list[nserv].sin_family = AF_INET;
                _res.nsaddr_list[nserv].sin_port = htons(NAMESERVER_PORT);
                nserv++;
                n++;
        }
        if (rtems_bsdnet_domain_name)
                (void)strncpy(_res.defdname, rtems_bsdnet_domain_name, sizeof(_res.defdname) - 1);
        }

        /* Allow user to override the local domain definition */
        if ((cp = getenv("LOCALDOMAIN")) != NULL) {
                (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
                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;
                    strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
                    if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
                            *cp = '\0';
                    havesearch = 0;
                    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;
                    strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
                    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 in_addr a;

                    cp = buf + sizeof("nameserver") - 1;
                    while (*cp == ' ' || *cp == '\t')
                        cp++;
                    if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
                        _res.nsaddr_list[nserv].sin_addr = a;
                        _res.nsaddr_list[nserv].sin_family = AF_INET;
                        _res.nsaddr_list[nserv].sin_port =
                                htons(NAMESERVER_PORT);
                        nserv++;
                    }
                    continue;
                }
#ifdef RESOLVSORT
                if (MATCH(buf, "sortlist")) {
                    struct in_addr a;

                    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((unsigned char)*cp) && !isspace((unsigned 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((unsigned char)*cp) && !isspace((unsigned 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);
                            }
                            nsort++;
                        }
                        *cp = n;
                    }
                    continue;
                }
#endif
                if (MATCH(buf, "options")) {
                    res_setoptions(buf + sizeof("options") - 1, "conf");
                    continue;
                }
            }
            if (nserv > 1) 
                _res.nscount = nserv;
#ifdef RESOLVSORT
            _res.nsort = nsort;
#endif
            (void) fclose(fp);
        }
        if (_res.defdname[0] == 0 &&
            gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
            (cp = strchr(buf, '.')) != NULL)
                strcpy(_res.defdname, cp + 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
#endif /* !RFC1535 */
        }

        if ((cp = getenv("RES_OPTIONS")) != NULL)
                res_setoptions(cp, "env");
        _res.options |= RES_INIT;
        return (0);
}

static void
res_setoptions(
        char *options,
        char *source)
{
        char *cp = options;
        int i;

#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;
                } else if (!strncmp(cp, "no_tld_query", sizeof("no_tld_query") - 1)) {
                        _res.options |= RES_NOTLDQUERY;
                } else {
                        /* XXX - print a warning here? */
                }
                /* skip to next run of spaces */
                while (*cp && *cp != ' ' && *cp != '\t')
                        cp++;
        }
}

#ifdef RESOLVSORT
/* XXX - should really support CIDR which means explicit masks always. */
static u_int32_t
net_mask(               /* XXX - should really use system's version of this */
        struct in_addr in)
{
        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));
}
#endif

u_int
res_randomid(void)
{
        struct timeval now;

        gettimeofday(&now, NULL);
        return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
}