common/resolv/res_init.c

/*
 * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.
 */


/*
 * 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 (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Portions Copyright (c) 1996-1999 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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 defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_init.c    8.1 (Berkeley) 6/7/93";
static const char rcsid[] = "$Id: res_init.c,v 1.26 2008/12/11 09:59:00 marka Exp $";
#endif /* LIBC_SCCS and not lint */

#include "port_before.h"

#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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>

#ifndef HAVE_MD5
# include "../dst/md5.h"
#else
# ifdef SOLARIS2
#  include <sys/md5.h>
# endif
#endif
#ifndef _MD5_H_
# define _MD5_H_ 1  /*%< make sure we do not include rsaref md5.h file */
#endif


#include "port_after.h"

/* ensure that sockaddr_in6 and IN6ADDR_ANY_INIT are declared / defined */
#include <resolv.h>

/* ISC purposely put port_after.h before <resolv.h> to force in6 stuff
 * (above) so we explicitly include port_resolv.h here */
#include "port_resolv.h"

#include "res_private.h"

/*% Options.  Should all be left alone. */
#define RESOLVSORT
#define DEBUG

#ifdef  SUNW_INITCHKIF
#include <net/if.h>
#include <netinet/if_ether.h>
#include <sys/sockio.h>
#define MAXIFS  8192
#endif  /* SUNW_INITCHKIF */

#ifdef SOLARIS2
#include <sys/systeminfo.h>
#endif

static void res_setoptions __P((res_state, const char *, const char *));

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

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

/*
 * Resolver state default settings.
 */

/*%
 * 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_ninit(res_state statp) {
    extern int __res_vinit(res_state, int);
    return (__res_vinit(statp, 0));
}

/*% This function has to be reachable by res_data.c but not publically. */
int
__res_vinit(res_state statp, int preinit) {
    register FILE *fp;
    register char *cp, **pp;
    register int n;
    char buf[BUFSIZ];
    int nserv = 0;    /*%< number of nameserver records read from file */
    int haveenv = 0;
    int havesearch = 0;
#ifdef RESOLVSORT
    int nsort = 0;
    char *net;
#endif
    int dots;
    union res_sockaddr_union u[2];
    int maxns = MAXNS;

    RES_SET_H_ERRNO(statp, 0);
    if (statp->_u._ext.ext != NULL)
        res_ndestroy(statp);

    if (!preinit) {
        statp->retrans = RES_TIMEOUT;
        statp->retry = RES_DFLRETRY;
        statp->options = RES_DEFAULT;
        res_rndinit(statp);
        statp->id = res_nrandomid(statp);
    }

    memset(u, 0, sizeof(u));
#ifdef USELOOPBACK
    u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
#else
    u[nserv].sin.sin_addr.s_addr = INADDR_ANY;
#endif
    u[nserv].sin.sin_family = AF_INET;
    u[nserv].sin.sin_port = htons(NAMESERVER_PORT);
#ifdef HAVE_SA_LEN
    u[nserv].sin.sin_len = sizeof(struct sockaddr_in);
#endif
    nserv++;
#ifdef HAS_INET6_STRUCTS
#ifdef USELOOPBACK
    u[nserv].sin6.sin6_addr = in6addr_loopback;
#else
    u[nserv].sin6.sin6_addr = in6addr_any;
#endif
    u[nserv].sin6.sin6_family = AF_INET6;
    u[nserv].sin6.sin6_port = htons(NAMESERVER_PORT);
#ifdef HAVE_SA_LEN
    u[nserv].sin6.sin6_len = sizeof(struct sockaddr_in6);
#endif
    nserv++;
#endif
    statp->nscount = 0;
    statp->ndots = 1;
    statp->pfcode = 0;
    statp->_vcsock = -1;
    statp->_flags = 0;
    statp->qhook = NULL;
    statp->rhook = NULL;
    statp->_u._ext.nscount = 0;
    statp->_u._ext.ext = malloc(sizeof(*statp->_u._ext.ext));
    if (statp->_u._ext.ext != NULL) {
            memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
        statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
        strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");
        strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");
    } else {
        /*
         * Historically res_init() rarely, if at all, failed.
         * Examples and applications exist which do not check
         * our return code.  Furthermore several applications
         * simply call us to get the systems domainname.  So
         * rather then immediately fail here we store the
         * failure, which is returned later, in h_errno.  And
         * prevent the collection of 'nameserver' information
         * by setting maxns to 0.  Thus applications that fail
         * to check our return code wont be able to make
         * queries anyhow.
         */
        RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
        maxns = 0;
    }
#ifdef RESOLVSORT
    statp->nsort = 0;
#endif
    res_setservers(statp, u, nserv);

#ifdef  SUNW_INITCHKIF
/*
 * Short circuit res_init() if no non-loopback interfaces are up. This is
 * done to avoid boot delays if "dns" comes before "files" in nsswitch.conf.
 * An additional fix has been added to this code, to count all external
 * interfaces, which includes the IPv6 interfaces. If no external interfaces
 * are found, an additional check is carried out to determine if any deprecated
 * interfaces are up.
 */
    {
        int s;
        struct lifnum lifn;

        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
            perror("res_init: socket");
            goto freedata;
        }
        lifn.lifn_family = AF_UNSPEC;
        lifn.lifn_flags = LIFC_EXTERNAL_SOURCE;
        if (ioctl(s, SIOCGLIFNUM, (char *)&lifn) < 0) {
            close(s);
            goto freedata;
        }
        if (lifn.lifn_count == 0) {
            /*
             * Check if there are any deprecated interfaces up
             */
            struct lifconf lifc;
            uchar_t *buf;
            int buflen, i, int_up = 0;

            lifn.lifn_flags = 0;
            if ((ioctl(s, SIOCGLIFNUM, (char *)&lifn) < 0) ||
                    (lifn.lifn_count < 1)) {
                close(s);
                goto freedata;
            }

            buflen = lifn.lifn_count * sizeof (struct lifreq);
            buf = (uchar_t *)malloc(buflen);
            if (buf == NULL) {
                close(s);
                goto freedata;
            }

            lifc.lifc_family = AF_UNSPEC;
            lifc.lifc_flags = 0;
            lifc.lifc_len = buflen;
            lifc.lifc_lifcu.lifcu_buf = (caddr_t)buf;
            if (ioctl(s, SIOCGLIFCONF, (char *)&lifc) < 0) {
                close(s);
                free(buf);
                goto freedata;
            }

            for (i = 0; i < lifn.lifn_count; ++i) {
                struct lifreq *lreqp, lreq;

                lreqp = (struct lifreq *)&lifc.lifc_req[i];
                strlcpy(lreq.lifr_name, lreqp->lifr_name,
                        sizeof (lreq.lifr_name));
                if (ioctl(s, SIOCGLIFFLAGS, &lreq) < 0) {
                    close(s);
                    free(buf);
                    goto freedata;
                }
                if ((lreq.lifr_flags & IFF_UP) &&
                    !(lreq.lifr_flags & IFF_NOLOCAL) &&
                    !(lreq.lifr_flags & IFF_NOXMIT) &&
                    !(lreq.lifr_flags & IFF_LOOPBACK)) {
                    int_up = 1;
                    break;
                }
            }
            free(buf);

            if (!int_up) {
                close(s);
                goto freedata;
            }
        }
        close(s);
    }
#endif  /* SUNW_INITCHKIF */

#ifdef  SOLARIS2
    /*
     * The old libresolv derived the defaultdomain from NIS/NIS+.
     * We want to keep this behaviour
     */
    {
        char buf[sizeof(statp->defdname)], *cp;
        int ret;

        if ((ret = sysinfo(SI_SRPC_DOMAIN, buf, sizeof(buf))) > 0 &&
            (unsigned int)ret <= sizeof(buf)) {
            if (buf[0] == '+')
                buf[0] = '.';
            cp = strchr(buf, '.');
            cp = (cp == NULL) ? buf : (cp + 1);
            strncpy(statp->defdname, cp,
                sizeof(statp->defdname) - 1);
            statp->defdname[sizeof(statp->defdname) - 1] = '\0';
        }
    }
#endif  /* SOLARIS2 */

    /* Allow user to override the local domain definition */
    if ((cp = getenv("LOCALDOMAIN")) != NULL) {
        (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
        statp->defdname[sizeof(statp->defdname) - 1] = '\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 = statp->defdname;
        pp = statp->dnsrch;
        *pp++ = cp;
        for (n = 0; *cp && pp < statp->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'))

    nserv = 0;
    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(statp->defdname, cp, sizeof(statp->defdname) - 1);
            statp->defdname[sizeof(statp->defdname) - 1] = '\0';
            if ((cp = strpbrk(statp->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(statp->defdname, cp, sizeof(statp->defdname) - 1);
            statp->defdname[sizeof(statp->defdname) - 1] = '\0';
            if ((cp = strchr(statp->defdname, '\n')) != NULL)
                *cp = '\0';
            /*
             * Set search list to be blank-separated strings
             * on rest of line.
             */
            cp = statp->defdname;
            pp = statp->dnsrch;
            *pp++ = cp;
            for (n = 0; *cp && pp < statp->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, *ai;
            char sbuf[NI_MAXSERV];
            const size_t minsiz =
                sizeof(statp->_u._ext.ext->nsaddrs[0]);

            cp = buf + sizeof("nameserver") - 1;
            while (*cp == ' ' || *cp == '\t')
            cp++;
            cp[strcspn(cp, ";# \t\n")] = '\0';
            if ((*cp != '\0') && (*cp != '\n')) {
            memset(&hints, 0, sizeof(hints));
            hints.ai_family = PF_UNSPEC;
            hints.ai_socktype = SOCK_DGRAM; /*dummy*/
            hints.ai_flags = AI_NUMERICHOST;
            sprintf(sbuf, "%u", NAMESERVER_PORT);
            if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
                ai->ai_addrlen <= minsiz) {
                if (statp->_u._ext.ext != NULL) {
                memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
                    ai->ai_addr, ai->ai_addrlen);
                }
                if (ai->ai_addrlen <=
                    sizeof(statp->nsaddr_list[nserv])) {
                memcpy(&statp->nsaddr_list[nserv],
                    ai->ai_addr, ai->ai_addrlen);
                } else
                statp->nsaddr_list[nserv].sin_family = 0;
                freeaddrinfo(ai);
                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(*cp) && !isspace((unsigned char)*cp))
                cp++;
            n = *cp;
            *cp = 0;
            if (inet_aton(net, &a)) {
                statp->sort_list[nsort].addr = a;
                if (ISSORTMASK(n)) {
                *cp++ = n;
                net = cp;
                while (*cp && *cp != ';' &&
                    isascii(*cp) &&
                    !isspace((unsigned char)*cp))
                    cp++;
                n = *cp;
                *cp = 0;
                if (inet_aton(net, &a)) {
                    statp->sort_list[nsort].mask = a.s_addr;
                } else {
                    statp->sort_list[nsort].mask =
                    net_mask(statp->sort_list[nsort].addr);
                }
                } else {
                statp->sort_list[nsort].mask =
                    net_mask(statp->sort_list[nsort].addr);
                }
                nsort++;
            }
            *cp = n;
            }
            continue;
        }
#endif
        if (MATCH(buf, "options")) {
            res_setoptions(statp, buf + sizeof("options") - 1, "conf");
            continue;
        }
        }
        if (nserv > 0)
        statp->nscount = nserv;
#ifdef RESOLVSORT
        statp->nsort = nsort;
#endif
        (void) fclose(fp);
    }
/*
 * Last chance to get a nameserver.  This should not normally
 * be necessary
 */
#ifdef NO_RESOLV_CONF
    if(nserv == 0)
        nserv = get_nameservers(statp);
#endif

    if (statp->defdname[0] == 0 &&
        gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
        (cp = strchr(buf, '.')) != NULL)
        strcpy(statp->defdname, cp + 1);

    /* find components of local domain that might be searched */
    if (havesearch == 0) {
        pp = statp->dnsrch;
        *pp++ = statp->defdname;
        *pp = NULL;

        dots = 0;
        for (cp = statp->defdname; *cp; cp++)
            dots += (*cp == '.');

        cp = statp->defdname;
        while (pp < statp->dnsrch + MAXDFLSRCH) {
            if (dots < LOCALDOMAINPARTS)
                break;
            cp = strchr(cp, '.') + 1;    /*%< we know there is one */
            *pp++ = cp;
            dots--;
        }
        *pp = NULL;
#ifdef DEBUG
        if (statp->options & RES_DEBUG) {
            printf(";; res_init()... default dnsrch list:\n");
            for (pp = statp->dnsrch; *pp; pp++)
                printf(";;\t%s\n", *pp);
            printf(";;\t..END..\n");
        }
#endif
    }

    if ((cp = getenv("RES_OPTIONS")) != NULL)
        res_setoptions(statp, cp, "env");
    statp->options |= RES_INIT;
    return (statp->res_h_errno);
#ifdef  SUNW_INITCHKIF
freedata:
    RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
    if (statp->_u._ext.ext != NULL) {
        free(statp->_u._ext.ext);
        statp->_u._ext.ext = NULL;
    }
    return (-1);
#endif  /* SUNW_INITCHKIF */

}

static void
res_setoptions(res_state statp, const char *options, const char *source)
{
    const char *cp = options;
    int i;
    struct __res_state_ext *ext = statp->_u._ext.ext;

#ifdef DEBUG
    if (statp->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)
                statp->ndots = i;
            else
                statp->ndots = RES_MAXNDOTS;
#ifdef DEBUG
            if (statp->options & RES_DEBUG)
                printf(";;\tndots=%d\n", statp->ndots);
#endif
        } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
            i = atoi(cp + sizeof("timeout:") - 1);
            if (i <= RES_MAXRETRANS)
                statp->retrans = i;
            else
                statp->retrans = RES_MAXRETRANS;
#ifdef DEBUG
            if (statp->options & RES_DEBUG)
                printf(";;\ttimeout=%d\n", statp->retrans);
#endif
#ifdef  SOLARIS2
        } else if (!strncmp(cp, "retrans:", sizeof("retrans:") - 1)) {
            /*
             * For backward compatibility, 'retrans' is
             * supported as an alias for 'timeout', though
             * without an imposed maximum.
             */
            statp->retrans = atoi(cp + sizeof("retrans:") - 1);
        } else if (!strncmp(cp, "retry:", sizeof("retry:") - 1)){
            /*
             * For backward compatibility, 'retry' is
             * supported as an alias for 'attempts', though
             * without an imposed maximum.
             */
            statp->retry = atoi(cp + sizeof("retry:") - 1);
#endif  /* SOLARIS2 */
        } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
            i = atoi(cp + sizeof("attempts:") - 1);
            if (i <= RES_MAXRETRY)
                statp->retry = i;
            else
                statp->retry = RES_MAXRETRY;
#ifdef DEBUG
            if (statp->options & RES_DEBUG)
                printf(";;\tattempts=%d\n", statp->retry);
#endif
        } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
#ifdef DEBUG
            if (!(statp->options & RES_DEBUG)) {
                printf(";; res_setoptions(\"%s\", \"%s\")..\n",
                       options, source);
                statp->options |= RES_DEBUG;
            }
            printf(";;\tdebug\n");
#endif
        } else if (!strncmp(cp, "no_tld_query",
                    sizeof("no_tld_query") - 1) ||
               !strncmp(cp, "no-tld-query",
                    sizeof("no-tld-query") - 1)) {
            statp->options |= RES_NOTLDQUERY;
        } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
            statp->options |= RES_USE_INET6;
        } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
            statp->options |= RES_ROTATE;
        } else if (!strncmp(cp, "no-check-names",
                    sizeof("no-check-names") - 1)) {
            statp->options |= RES_NOCHECKNAME;
        }
#ifdef RES_USE_EDNS0
        else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
            statp->options |= RES_USE_EDNS0;
        }
#endif
        else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
            statp->options |= RES_USE_DNAME;
        }
        else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
            if (ext == NULL)
                goto skip;
            cp += sizeof("nibble:") - 1;
            i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
            strncpy(ext->nsuffix, cp, i);
            ext->nsuffix[i] = '\0';
        }
        else if (!strncmp(cp, "nibble2:", sizeof("nibble2:") - 1)) {
            if (ext == NULL)
                goto skip;
            cp += sizeof("nibble2:") - 1;
            i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix2) - 1);
            strncpy(ext->nsuffix2, cp, i);
            ext->nsuffix2[i] = '\0';
        }
        else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
            cp += sizeof("v6revmode:") - 1;
            /* "nibble" and "bitstring" used to be valid */
            if (!strncmp(cp, "single", sizeof("single") - 1)) {
                statp->options |= RES_NO_NIBBLE2;
            } else if (!strncmp(cp, "both", sizeof("both") - 1)) {
                statp->options &=
                     ~RES_NO_NIBBLE2;
            }
        }
        else {
            /* XXX - print a warning here? */
        }
   skip:
        /* 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(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));
}
#endif

void
res_rndinit(res_state statp)
{
    struct timeval now;
    u_int32_t u32;
    u_int16_t u16;

    gettimeofday(&now, NULL);
    u32 = now.tv_sec;
    memcpy(statp->_u._ext._rnd, &u32, 4);
    u32 = now.tv_usec;
    memcpy(statp->_u._ext._rnd + 4, &u32, 4);
    u32 += now.tv_sec;
    memcpy(statp->_u._ext._rnd + 8, &u32, 4);
    u16 = getpid();
    memcpy(statp->_u._ext._rnd + 12, &u16, 2);

}

u_int
res_nrandomid(res_state statp) {
    struct timeval now;
    u_int16_t u16;
    MD5_CTX ctx;

    gettimeofday(&now, NULL);
    u16 = (u_int16_t) (now.tv_sec ^ now.tv_usec);

    memcpy(statp->_u._ext._rnd + 14, &u16, 2);
#ifndef HAVE_MD5
    MD5_Init(&ctx);
    MD5_Update(&ctx, statp->_u._ext._rnd, 16);
    MD5_Final(statp->_u._ext._rnd, &ctx);
#else
    MD5Init(&ctx);
    MD5Update(&ctx, statp->_u._ext._rnd, 16);
    MD5Final(statp->_u._ext._rnd, &ctx);
#endif
    memcpy(&u16, statp->_u._ext._rnd + 14, 2);
    return ((u_int) u16);
}

/*%
 * This routine is for closing the socket if a virtual circuit is used and
 * the program wants to close it.  This provides support for endhostent()
 * which expects to close the socket.
 *
 * This routine is not expected to be user visible.
 */
void
res_nclose(res_state statp) {
    int ns;

    if (statp->_vcsock >= 0) {
        (void) close(statp->_vcsock);
        statp->_vcsock = -1;
        statp->_flags &= ~(RES_F_VC | RES_F_CONN);
    }
    for (ns = 0; ns < statp->_u._ext.nscount; ns++) {
        if (statp->_u._ext.nssocks[ns] != -1) {
            (void) close(statp->_u._ext.nssocks[ns]);
            statp->_u._ext.nssocks[ns] = -1;
        }
    }
}

void
res_ndestroy(res_state statp) {
    res_nclose(statp);
    if (statp->_u._ext.ext != NULL)
        free(statp->_u._ext.ext);
    statp->options &= ~RES_INIT;
    statp->_u._ext.ext = NULL;
}

const char *
res_get_nibblesuffix(res_state statp) {
    if (statp->_u._ext.ext)
        return (statp->_u._ext.ext->nsuffix);
    return ("ip6.arpa");
}

const char *
res_get_nibblesuffix2(res_state statp) {
    if (statp->_u._ext.ext)
        return (statp->_u._ext.ext->nsuffix2);
    return ("ip6.int");
}

void
res_setservers(res_state statp, const union res_sockaddr_union *set, int cnt) {
    int i, nserv;
    size_t size;

    /* close open servers */
    res_nclose(statp);

    /* cause rtt times to be forgotten */
    statp->_u._ext.nscount = 0;

    nserv = 0;
    for (i = 0; i < cnt && nserv < MAXNS; i++) {
        switch (set->sin.sin_family) {
        case AF_INET:
            size = sizeof(set->sin);
            if (statp->_u._ext.ext)
                memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
                    &set->sin, size);
            if (size <= sizeof(statp->nsaddr_list[nserv]))
                memcpy(&statp->nsaddr_list[nserv],
                    &set->sin, size);
            else
                statp->nsaddr_list[nserv].sin_family = 0;
            nserv++;
            break;

#ifdef HAS_INET6_STRUCTS
        case AF_INET6:
            size = sizeof(set->sin6);
            if (statp->_u._ext.ext)
                memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
                    &set->sin6, size);
            if (size <= sizeof(statp->nsaddr_list[nserv]))
                memcpy(&statp->nsaddr_list[nserv],
                    &set->sin6, size);
            else
                statp->nsaddr_list[nserv].sin_family = 0;
            nserv++;
            break;
#endif

        default:
            break;
        }
        set++;
    }
    statp->nscount = nserv;

}

int
res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
    int i;
    size_t size;
    u_int16_t family;

    for (i = 0; i < statp->nscount && i < cnt; i++) {
        if (statp->_u._ext.ext)
            family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
        else
            family = statp->nsaddr_list[i].sin_family;

        switch (family) {
        case AF_INET:
            size = sizeof(set->sin);
            if (statp->_u._ext.ext)
                memcpy(&set->sin,
                       &statp->_u._ext.ext->nsaddrs[i],
                       size);
            else
                memcpy(&set->sin, &statp->nsaddr_list[i],
                       size);
            break;

#ifdef HAS_INET6_STRUCTS
        case AF_INET6:
            size = sizeof(set->sin6);
            if (statp->_u._ext.ext)
                memcpy(&set->sin6,
                       &statp->_u._ext.ext->nsaddrs[i],
                       size);
            else
                memcpy(&set->sin6, &statp->nsaddr_list[i],
                       size);
            break;
#endif

        default:
            set->sin.sin_family = 0;
            break;
        }
        set++;
    }
    return (statp->nscount);
}

/*! \file */