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res_init.c

/*
 * ++Copyright++ 1985, 1989, 1993
 * -
 * 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--
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_init.c    8.1 (Berkeley) 6/7/93";
static char rcsid[] = "$Id: res_init.c,v 1.1.1.1 1998/02/10 21:01:47 mea Exp $";
#endif /* LIBC_SCCS and not lint */

#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 <stdio.h>
#include <ctype.h>
#include "resolv.h"
#if defined(BSD) && (BSD >= 199103)
# include <unistd.h>
# include <stdlib.h>
# include <string.h>
#else
# include "portability.h"
#endif

/*-------------------------------------- info about "sortlist" --------------
 * Marc Majka           1994/04/16
 * Allan Nathanson      1994/10/29 (BIND 4.9.3.x)
 *
 * NetInfo resolver configuration directory support.
 *
 * Allow a NetInfo directory to be created in the hierarchy which
 * contains the same information as the resolver configuration file.
 *
 * - The local domain name is stored as the value of the "domain" property.
 * - The Internet address(es) of the name server(s) are stored as values
 *   of the "nameserver" property.
 * - The name server addresses are stored as values of the "nameserver"
 *   property.
 * - The search list for host-name lookup is stored as values of the
 *   "search" property.
 * - The sortlist comprised of IP address netmask pairs are stored as
 *   values of the "sortlist" property. The IP address and optional netmask
 *   should be seperated by a slash (/) or ampersand (&) character.
 * - Internal resolver variables can be set from the value of the "options"
 *   property.
 */
#if defined(NeXT)
#  include <netinfo/ni.h>
#  define NI_PATH_RESCONF "/locations/resolver"
#  define NI_TIMEOUT 10
static int netinfo_res_init __P((int *haveenv, int *havesearch));
#endif

#if defined(USE_OPTIONS_H)
# include "../conf/options.h"
#endif

static void res_setoptions __P((char *, 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.
 */

struct __res_state _res;

/*
 * 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[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
#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;

      /* 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'))

#ifdef      NeXT
      if (netinfo_res_init(&haveenv, &havesearch) == 0)
#endif
      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(*cp) && !isspace(*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(*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 /* DEBUG */
#endif /* !RFC1535 */
      }

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

static void
res_setoptions(options, source)
      char *options, *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 {
                  /* 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(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

#ifdef      NeXT
static int
netinfo_res_init(haveenv, havesearch)
      int *haveenv;
      int *havesearch;
{
    register      int n;
    void    *domain, *parent;
    ni_id   dir;
    ni_status     status;
    ni_namelist   nl;
    int           nserv = 0;
#ifdef RESOLVSORT
    int           nsort = 0;
#endif

    status = ni_open(NULL, ".", &domain);
    if (status == NI_OK) {
      ni_setreadtimeout(domain, NI_TIMEOUT);
      ni_setabort(domain, 1);

      /* climb the NetInfo hierarchy to find a resolver directory */
      while (status == NI_OK) {
          status = ni_pathsearch(domain, &dir, NI_PATH_RESCONF);
          if (status == NI_OK) {
          /* found a resolver directory */

            if (*haveenv == 0) {
                /* get the default domain name */
                status = ni_lookupprop(domain, &dir, "domain", &nl);
                if (status == NI_OK && nl.ni_namelist_len > 0) {
                  (void)strncpy(_res.defdname,
                              nl.ni_namelist_val[0],
                              sizeof(_res.defdname) - 1);
                  _res.defdname[sizeof(_res.defdname) - 1] = '\0';
                  ni_namelist_free(&nl);
                  *havesearch = 0;
                }

                /* get search list */
                status = ni_lookupprop(domain, &dir, "search", &nl);
                if (status == NI_OK && nl.ni_namelist_len > 0) {
                  (void)strncpy(_res.defdname,
                              nl.ni_namelist_val[0],
                              sizeof(_res.defdname) - 1);
                  _res.defdname[sizeof(_res.defdname) - 1] = '\0';
                  /* copy  */
                  for (n = 0;
                       n < nl.ni_namelist_len && n < MAXDNSRCH;
                       n++) {
                       /* duplicate up to MAXDNSRCH servers */
                       char *cp = nl.ni_namelist_val[n];
                      _res.dnsrch[n] =
                        strcpy((char *)malloc(strlen(cp) + 1), cp);
                  }
                  ni_namelist_free(&nl);
                  *havesearch = 1;
                }
            }

            /* get list of nameservers */
            status = ni_lookupprop(domain, &dir, "nameserver", &nl);
            if (status == NI_OK && nl.ni_namelist_len > 0) {
                /* copy up to MAXNS servers */
                for (n = 0;
                     n < nl.ni_namelist_len && nserv < MAXNS;
                   n++) {
                  struct in_addr a;

                  if (inet_aton(nl.ni_namelist_val[n], &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++;
                  }
                }
                ni_namelist_free(&nl);
            }
            
            if (nserv > 1)
                _res.nscount = nserv;

#ifdef RESOLVSORT
            /* get sort order */
            status = ni_lookupprop(domain, &dir, "sortlist", &nl);
            if (status == NI_OK && nl.ni_namelist_len > 0) {

                /* copy up to MAXRESOLVSORT address/netmask pairs */
                for (n = 0;
                     n < nl.ni_namelist_len && nsort < MAXRESOLVSORT;
                   n++) {
                  char ch;
                  char *cp;
                  const char *sp;
                  struct in_addr a;

                  cp = NULL;
                  for (sp = sort_mask; *sp; sp++) {
                        char *cp1;
                        cp1 = strchr(nl.ni_namelist_val[n], *sp);
                        if (cp && cp1)
                              cp = (cp < cp1)? cp : cp1;
                        else if (cp1)
                              cp = cp1;
                  }
                  if (cp != NULL) {
                        ch = *cp;
                        *cp = '\0';
                        break;
                  }
                  if (inet_aton(nl.ni_namelist_val[n], &a)) {
                      _res.sort_list[nsort].addr = a;
                      if (*cp && ISSORTMASK(ch)) {
                        *cp++ = ch;
                          if (inet_aton(cp, &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++;
                  }
                }
                ni_namelist_free(&nl);
            }

            _res.nsort = nsort;
#endif

            /* get resolver options */
            status = ni_lookupprop(domain, &dir, "options", &nl);
            if (status == NI_OK && nl.ni_namelist_len > 0) {
                res_setoptions(nl.ni_namelist_val[0], "conf");
                ni_namelist_free(&nl);
            }

            ni_free(domain);
            return(1);  /* using DNS configuration from NetInfo */
          }

          status = ni_open(domain, "..", &parent);
          ni_free(domain);
          if (status == NI_OK)
            domain = parent;
      }
    }
    return(0);    /* if not using DNS configuration from NetInfo */
}
#endif      /* NeXT */

u_int16_t
res_randomid()
{
      struct timeval now;

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

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