forward.c

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/*
 * Copyright (C) 2004, 2005, 2007, 2009, 2013  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: forward.c,v 1.14 2009/09/02 23:48:02 tbox Exp $ */

/*! \file */

#include <config.h>

#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/rwlock.h>
#include <isc/sockaddr.h>
#include <isc/util.h>

#include <dns/forward.h>
#include <dns/rbt.h>
#include <dns/result.h>
#include <dns/types.h>

struct dns_fwdtable {
        /* Unlocked. */
        unsigned int            magic;
        isc_mem_t               *mctx;
        isc_rwlock_t            rwlock;
        /* Locked by lock. */
        dns_rbt_t               *table;
};

#define FWDTABLEMAGIC           ISC_MAGIC('F', 'w', 'd', 'T')
#define VALID_FWDTABLE(ft)      ISC_MAGIC_VALID(ft, FWDTABLEMAGIC)

static void
auto_detach(void *, void *);

isc_result_t
dns_fwdtable_create(isc_mem_t *mctx, dns_fwdtable_t **fwdtablep) {
        dns_fwdtable_t *fwdtable;
        isc_result_t result;

        REQUIRE(fwdtablep != NULL && *fwdtablep == NULL);

        fwdtable = isc_mem_get(mctx, sizeof(dns_fwdtable_t));
        if (fwdtable == NULL)
                return (ISC_R_NOMEMORY);

        fwdtable->table = NULL;
        result = dns_rbt_create(mctx, auto_detach, fwdtable, &fwdtable->table);
        if (result != ISC_R_SUCCESS)
                goto cleanup_fwdtable;

        result = isc_rwlock_init(&fwdtable->rwlock, 0, 0);
        if (result != ISC_R_SUCCESS)
                goto cleanup_rbt;

        fwdtable->mctx = NULL;
        isc_mem_attach(mctx, &fwdtable->mctx);
        fwdtable->magic = FWDTABLEMAGIC;
        *fwdtablep = fwdtable;

        return (ISC_R_SUCCESS);

   cleanup_rbt:
        dns_rbt_destroy(&fwdtable->table);

   cleanup_fwdtable:
        isc_mem_put(mctx, fwdtable, sizeof(dns_fwdtable_t));

        return (result);
}

isc_result_t
dns_fwdtable_addfwd(dns_fwdtable_t *fwdtable, dns_name_t *name,
                    dns_forwarderlist_t *fwdrs, dns_fwdpolicy_t fwdpolicy)
{
        isc_result_t result;
        dns_forwarders_t *forwarders;
        dns_forwarder_t *fwd, *nfwd;

        REQUIRE(VALID_FWDTABLE(fwdtable));

        forwarders = isc_mem_get(fwdtable->mctx, sizeof(dns_forwarders_t));
        if (forwarders == NULL)
                return (ISC_R_NOMEMORY);

        ISC_LIST_INIT(forwarders->fwdrs);
        for (fwd = ISC_LIST_HEAD(*fwdrs);
             fwd != NULL;
             fwd = ISC_LIST_NEXT(fwd, link))
        {
                nfwd = isc_mem_get(fwdtable->mctx, sizeof(dns_forwarder_t));
                if (nfwd == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto cleanup;
                }
                *nfwd = *fwd;
                ISC_LINK_INIT(nfwd, link);
                ISC_LIST_APPEND(forwarders->fwdrs, nfwd, link);
        }
        forwarders->fwdpolicy = fwdpolicy;

        RWLOCK(&fwdtable->rwlock, isc_rwlocktype_write);
        result = dns_rbt_addname(fwdtable->table, name, forwarders);
        RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_write);

        if (result != ISC_R_SUCCESS)
                goto cleanup;

        return (ISC_R_SUCCESS);

 cleanup:
        while (!ISC_LIST_EMPTY(forwarders->fwdrs)) {
                fwd = ISC_LIST_HEAD(forwarders->fwdrs);
                ISC_LIST_UNLINK(forwarders->fwdrs, fwd, link);
                isc_mem_put(fwdtable->mctx, fwd, sizeof(isc_sockaddr_t));
        }
        isc_mem_put(fwdtable->mctx, forwarders, sizeof(dns_forwarders_t));
        return (result);
}

isc_result_t
dns_fwdtable_add(dns_fwdtable_t *fwdtable, dns_name_t *name,
                 isc_sockaddrlist_t *addrs, dns_fwdpolicy_t fwdpolicy)
{
        isc_result_t result;
        dns_forwarders_t *forwarders;
        dns_forwarder_t *fwd;
        isc_sockaddr_t *sa;

        REQUIRE(VALID_FWDTABLE(fwdtable));

        forwarders = isc_mem_get(fwdtable->mctx, sizeof(dns_forwarders_t));
        if (forwarders == NULL)
                return (ISC_R_NOMEMORY);

        ISC_LIST_INIT(forwarders->fwdrs);
        for (sa = ISC_LIST_HEAD(*addrs);
             sa != NULL;
             sa = ISC_LIST_NEXT(sa, link))
        {
                fwd = isc_mem_get(fwdtable->mctx, sizeof(dns_forwarder_t));
                if (fwd == NULL) {
                        result = ISC_R_NOMEMORY;
                        goto cleanup;
                }
                fwd->addr = *sa;
                fwd->dscp = -1;
                ISC_LINK_INIT(fwd, link);
                ISC_LIST_APPEND(forwarders->fwdrs, fwd, link);
        }
        forwarders->fwdpolicy = fwdpolicy;

        RWLOCK(&fwdtable->rwlock, isc_rwlocktype_write);
        result = dns_rbt_addname(fwdtable->table, name, forwarders);
        RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_write);

        if (result != ISC_R_SUCCESS)
                goto cleanup;

        return (ISC_R_SUCCESS);

 cleanup:
        while (!ISC_LIST_EMPTY(forwarders->fwdrs)) {
                fwd = ISC_LIST_HEAD(forwarders->fwdrs);
                ISC_LIST_UNLINK(forwarders->fwdrs, fwd, link);
                isc_mem_put(fwdtable->mctx, fwd, sizeof(dns_forwarder_t));
        }
        isc_mem_put(fwdtable->mctx, forwarders, sizeof(dns_forwarders_t));
        return (result);
}

isc_result_t
dns_fwdtable_delete(dns_fwdtable_t *fwdtable, dns_name_t *name) {
        isc_result_t result;

        REQUIRE(VALID_FWDTABLE(fwdtable));

        RWLOCK(&fwdtable->rwlock, isc_rwlocktype_write);
        result = dns_rbt_deletename(fwdtable->table, name, ISC_FALSE);
        RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_write);

        if (result == DNS_R_PARTIALMATCH)
                result = ISC_R_NOTFOUND;

        return (result);
}

isc_result_t
dns_fwdtable_find(dns_fwdtable_t *fwdtable, dns_name_t *name,
                  dns_forwarders_t **forwardersp)
{
        return (dns_fwdtable_find2(fwdtable, name, NULL, forwardersp));
}

isc_result_t
dns_fwdtable_find2(dns_fwdtable_t *fwdtable, dns_name_t *name,
                   dns_name_t *foundname, dns_forwarders_t **forwardersp)
{
        isc_result_t result;

        REQUIRE(VALID_FWDTABLE(fwdtable));

        RWLOCK(&fwdtable->rwlock, isc_rwlocktype_read);

        result = dns_rbt_findname(fwdtable->table, name, 0, foundname,
                                  (void **)forwardersp);
        if (result == DNS_R_PARTIALMATCH)
                result = ISC_R_SUCCESS;

        RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_read);

        return (result);
}

void
dns_fwdtable_destroy(dns_fwdtable_t **fwdtablep) {
        dns_fwdtable_t *fwdtable;
        isc_mem_t *mctx;

        REQUIRE(fwdtablep != NULL && VALID_FWDTABLE(*fwdtablep));

        fwdtable = *fwdtablep;

        dns_rbt_destroy(&fwdtable->table);
        isc_rwlock_destroy(&fwdtable->rwlock);
        fwdtable->magic = 0;
        mctx = fwdtable->mctx;
        isc_mem_put(mctx, fwdtable, sizeof(dns_fwdtable_t));
        isc_mem_detach(&mctx);

        *fwdtablep = NULL;
}

/***
 *** Private
 ***/

static void
auto_detach(void *data, void *arg) {
        dns_forwarders_t *forwarders = data;
        dns_fwdtable_t *fwdtable = arg;
        dns_forwarder_t *fwd;

        UNUSED(arg);

        while (!ISC_LIST_EMPTY(forwarders->fwdrs)) {
                fwd = ISC_LIST_HEAD(forwarders->fwdrs);
                ISC_LIST_UNLINK(forwarders->fwdrs, fwd, link);
                isc_mem_put(fwdtable->mctx, fwd, sizeof(dns_forwarder_t));
        }
        isc_mem_put(fwdtable->mctx, forwarders, sizeof(dns_forwarders_t));
}

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