bin/named/sortlist.c

	sortlist.c revision 70e5a7403f0e0a3bd292b8287c5fed5772c15270
/*
 * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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.
 */

/* $Id: sortlist.c,v 1.15 2007/06/19 23:46:59 tbox Exp $ */

/*! \file */

#include <config.h>

#include <isc/mem.h>
#include <isc/util.h>

#include <dns/acl.h>
#include <dns/result.h>

#include <named/globals.h>
#include <named/server.h>
#include <named/sortlist.h>

ns_sortlisttype_t
ns_sortlist_setup(dns_acl_t *acl, isc_netaddr_t *clientaddr,
          const void **argp)
{
    unsigned int i;

    if (acl == NULL)
        goto dont_sort;

    for (i = 0; i < acl->length; i++) {
        /*
         * 'e' refers to the current 'top level statement'
         * in the sortlist (see ARM).
         */
        dns_aclelement_t *e = &acl->elements[i];
        dns_aclelement_t *try_elt;
        dns_aclelement_t *order_elt = NULL;
        const dns_aclelement_t *matched_elt = NULL;

        if (e->type == dns_aclelementtype_nestedacl) {
            dns_acl_t *inner = e->u.nestedacl;

            if (inner->length < 1 || inner->length > 2)
                goto dont_sort;
            if (inner->elements[0].negative)
                goto dont_sort;
            try_elt = &inner->elements[0];
            if (inner->length == 2)
                order_elt = &inner->elements[1];
        } else {
            /*
             * BIND 8 allows bare elements at the top level
             * as an undocumented feature.
             */
            try_elt = e;
        }

        if (dns_aclelement_match(clientaddr, NULL, try_elt,
                     &ns_g_server->aclenv,
                     &matched_elt)) {
            if (order_elt != NULL) {
                if (order_elt->type ==
                    dns_aclelementtype_nestedacl) {
                    *argp = order_elt->u.nestedacl;
                    return (NS_SORTLISTTYPE_2ELEMENT);
                } else if (order_elt->type ==
                       dns_aclelementtype_localhost &&
                       ns_g_server->aclenv.localhost != NULL) {
                    *argp = ns_g_server->aclenv.localhost;
                    return (NS_SORTLISTTYPE_2ELEMENT);
                } else if (order_elt->type ==
                       dns_aclelementtype_localnets &&
                       ns_g_server->aclenv.localnets != NULL) {
                    *argp = ns_g_server->aclenv.localnets;
                    return (NS_SORTLISTTYPE_2ELEMENT);
                } else {
                    /*
                     * BIND 8 allows a bare IP prefix as
                     * the 2nd element of a 2-element
                     * sortlist statement.
                     */
                    *argp = order_elt;
                    return (NS_SORTLISTTYPE_1ELEMENT);
                }
            } else {
                INSIST(matched_elt != NULL);
                *argp = matched_elt;
                return (NS_SORTLISTTYPE_1ELEMENT);
            }
        }
    }

    /* No match; don't sort. */
 dont_sort:
    *argp = NULL;
    return (NS_SORTLISTTYPE_NONE);
}

int
ns_sortlist_addrorder2(const isc_netaddr_t *addr, const void *arg) {
    const dns_acl_t *sortacl = (const dns_acl_t *) arg;
    int match;

    (void)dns_acl_match(addr, NULL, sortacl,
                &ns_g_server->aclenv,
                &match, NULL);
    if (match > 0)
        return (match);
    else if (match < 0)
        return (INT_MAX - (-match));
    else
        return (INT_MAX / 2);
}

int
ns_sortlist_addrorder1(const isc_netaddr_t *addr, const void *arg) {
    const dns_aclelement_t *matchelt = (const dns_aclelement_t *) arg;
    if (dns_aclelement_match(addr, NULL, matchelt,
                 &ns_g_server->aclenv,
                 NULL)) {
        return (0);
    } else {
        return (INT_MAX);
    }
}

void
ns_sortlist_byaddrsetup(dns_acl_t *sortlist_acl, isc_netaddr_t *client_addr,
               dns_addressorderfunc_t *orderp,
               const void **argp)
{
    ns_sortlisttype_t sortlisttype;

    sortlisttype = ns_sortlist_setup(sortlist_acl, client_addr, argp);

    switch (sortlisttype) {
    case NS_SORTLISTTYPE_1ELEMENT:
        *orderp = ns_sortlist_addrorder1;
        break;
    case NS_SORTLISTTYPE_2ELEMENT:
        *orderp = ns_sortlist_addrorder2;
        break;
    case NS_SORTLISTTYPE_NONE:
        *orderp = NULL;
        break;
    default:
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "unexpected return from ns_sortlist_setup(): "
                 "%d", sortlisttype);
        break;
    }
}