lib/dns/keytable.c

/*
 * Copyright (C) 2004, 2005, 2007, 2012  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.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <isc/mem.h>
#include <isc/rwlock.h>
#include <isc/string.h>     /* Required for HP/UX (and others?) */
#include <isc/util.h>

#include <dns/keytable.h>
#include <dns/fixedname.h>
#include <dns/rbt.h>
#include <dns/result.h>

struct dns_keytable {
    /* Unlocked. */
    unsigned int        magic;
    isc_mem_t       *mctx;
    isc_mutex_t     lock;
    isc_rwlock_t        rwlock;
    /* Locked by lock. */
    isc_uint32_t        active_nodes;
    /* Locked by rwlock. */
    isc_uint32_t        references;
    dns_rbt_t       *table;
};

#define KEYTABLE_MAGIC          ISC_MAGIC('K', 'T', 'b', 'l')
#define VALID_KEYTABLE(kt)      ISC_MAGIC_VALID(kt, KEYTABLE_MAGIC)

struct dns_keynode {
    unsigned int        magic;
    dst_key_t *     key;
    struct dns_keynode *    next;
};

#define KEYNODE_MAGIC           ISC_MAGIC('K', 'N', 'o', 'd')
#define VALID_KEYNODE(kn)       ISC_MAGIC_VALID(kn, KEYNODE_MAGIC)

static void
free_keynode(void *node, void *arg) {
    dns_keynode_t *keynode = node;
    isc_mem_t *mctx = arg;

    REQUIRE(VALID_KEYNODE(keynode));
    dst_key_free(&keynode->key);
    if (keynode->next != NULL)
        free_keynode(keynode->next, mctx);
    isc_mem_put(mctx, keynode, sizeof(dns_keynode_t));
}

isc_result_t
dns_keytable_create(isc_mem_t *mctx, dns_keytable_t **keytablep) {
    dns_keytable_t *keytable;
    isc_result_t result;

    /*
     * Create a keytable.
     */

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

    keytable = isc_mem_get(mctx, sizeof(*keytable));
    if (keytable == NULL)
        return (ISC_R_NOMEMORY);

    keytable->table = NULL;
    result = dns_rbt_create(mctx, free_keynode, mctx, &keytable->table);
    if (result != ISC_R_SUCCESS)
        goto cleanup_keytable;

    result = isc_mutex_init(&keytable->lock);
    if (result != ISC_R_SUCCESS)
        goto cleanup_rbt;

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

    keytable->mctx = mctx;
    keytable->active_nodes = 0;
    keytable->references = 1;
    keytable->magic = KEYTABLE_MAGIC;
    *keytablep = keytable;

    return (ISC_R_SUCCESS);

   cleanup_lock:
    DESTROYLOCK(&keytable->lock);

   cleanup_rbt:
    dns_rbt_destroy(&keytable->table);

   cleanup_keytable:
    isc_mem_put(mctx, keytable, sizeof(*keytable));

    return (result);
}


void
dns_keytable_attach(dns_keytable_t *source, dns_keytable_t **targetp) {

    /*
     * Attach *targetp to source.
     */

    REQUIRE(VALID_KEYTABLE(source));
    REQUIRE(targetp != NULL && *targetp == NULL);

    RWLOCK(&source->rwlock, isc_rwlocktype_write);

    INSIST(source->references > 0);
    source->references++;
    INSIST(source->references != 0);

    RWUNLOCK(&source->rwlock, isc_rwlocktype_write);

    *targetp = source;
}

void
dns_keytable_detach(dns_keytable_t **keytablep) {
    isc_boolean_t destroy = ISC_FALSE;
    dns_keytable_t *keytable;

    /*
     * Detach *keytablep from its keytable.
     */

    REQUIRE(keytablep != NULL && VALID_KEYTABLE(*keytablep));

    keytable = *keytablep;

    RWLOCK(&keytable->rwlock, isc_rwlocktype_write);

    INSIST(keytable->references > 0);
    keytable->references--;
    LOCK(&keytable->lock);
    if (keytable->references == 0 && keytable->active_nodes == 0)
        destroy = ISC_TRUE;
    UNLOCK(&keytable->lock);

    RWUNLOCK(&keytable->rwlock, isc_rwlocktype_write);

    if (destroy) {
        dns_rbt_destroy(&keytable->table);
        isc_rwlock_destroy(&keytable->rwlock);
        DESTROYLOCK(&keytable->lock);
        keytable->magic = 0;
        isc_mem_put(keytable->mctx, keytable, sizeof(*keytable));
    }

    *keytablep = NULL;
}

isc_result_t
dns_keytable_add(dns_keytable_t *keytable, dst_key_t **keyp) {
    isc_result_t result;
    dns_keynode_t *knode;
    dns_rbtnode_t *node;
    dns_name_t *keyname;

    /*
     * Add '*keyp' to 'keytable'.
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(keyp != NULL);

    keyname = dst_key_name(*keyp);

    knode = isc_mem_get(keytable->mctx, sizeof(*knode));
    if (knode == NULL)
        return (ISC_R_NOMEMORY);

    RWLOCK(&keytable->rwlock, isc_rwlocktype_write);

    node = NULL;
    result = dns_rbt_addnode(keytable->table, keyname, &node);

    if (result == ISC_R_SUCCESS || result == ISC_R_EXISTS) {
        knode->magic = KEYNODE_MAGIC;
        knode->key = *keyp;
        knode->next = node->data;
        node->data = knode;
        *keyp = NULL;
        knode = NULL;
        result = ISC_R_SUCCESS;
    }

    RWUNLOCK(&keytable->rwlock, isc_rwlocktype_write);

    if (knode != NULL)
        isc_mem_put(keytable->mctx, knode, sizeof(*knode));

    return (result);
}

isc_result_t
dns_keytable_findkeynode(dns_keytable_t *keytable, dns_name_t *name,
             dns_secalg_t algorithm, dns_keytag_t tag,
             dns_keynode_t **keynodep)
{
    isc_result_t result;
    dns_keynode_t *knode;
    void *data;

    /*
     * Search for a key named 'name', matching 'algorithm' and 'tag' in
     * 'keytable'.
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(keynodep != NULL && *keynodep == NULL);

    RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

    /*
     * Note we don't want the DNS_R_PARTIALMATCH from dns_rbt_findname()
     * as that indicates that 'name' was not found.
     *
     * DNS_R_PARTIALMATCH indicates that the name was found but we
     * didn't get a match on algorithm and key id arguments.
     */
    knode = NULL;
    data = NULL;
    result = dns_rbt_findname(keytable->table, name, 0, NULL, &data);

    if (result == ISC_R_SUCCESS) {
        INSIST(data != NULL);
        for (knode = data; knode != NULL; knode = knode->next) {
            if (algorithm == dst_key_alg(knode->key)
                && tag == dst_key_id(knode->key))
                break;
        }
        if (knode != NULL) {
            LOCK(&keytable->lock);
            keytable->active_nodes++;
            UNLOCK(&keytable->lock);
            *keynodep = knode;
        } else
            result = DNS_R_PARTIALMATCH;
    } else if (result == DNS_R_PARTIALMATCH)
        result = ISC_R_NOTFOUND;

    RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

    return (result);
}

isc_result_t
dns_keytable_findnextkeynode(dns_keytable_t *keytable, dns_keynode_t *keynode,
                 dns_keynode_t **nextnodep)
{
    isc_result_t result;
    dns_keynode_t *knode;

    /*
     * Search for the next key with the same properties as 'keynode' in
     * 'keytable'.
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(VALID_KEYNODE(keynode));
    REQUIRE(nextnodep != NULL && *nextnodep == NULL);

    for (knode = keynode->next; knode != NULL; knode = knode->next) {
        if (dst_key_alg(keynode->key) == dst_key_alg(knode->key) &&
            dst_key_id(keynode->key) == dst_key_id(knode->key))
            break;
    }
    if (knode != NULL) {
        LOCK(&keytable->lock);
        keytable->active_nodes++;
        UNLOCK(&keytable->lock);
        result = ISC_R_SUCCESS;
        *nextnodep = knode;
    } else
        result = ISC_R_NOTFOUND;

    return (result);
}

isc_result_t
dns_keytable_finddeepestmatch(dns_keytable_t *keytable, dns_name_t *name,
                  dns_name_t *foundname)
{
    isc_result_t result;
    void *data;

    /*
     * Search for the deepest match in 'keytable'.
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(foundname != NULL);

    RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

    data = NULL;
    result = dns_rbt_findname(keytable->table, name, 0, foundname, &data);

    if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
        result = ISC_R_SUCCESS;

    RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

    return (result);
}

void
dns_keytable_detachkeynode(dns_keytable_t *keytable, dns_keynode_t **keynodep)
{
    /*
     * Give back a keynode found via dns_keytable_findkeynode().
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(keynodep != NULL && VALID_KEYNODE(*keynodep));

    LOCK(&keytable->lock);
    INSIST(keytable->active_nodes > 0);
    keytable->active_nodes--;
    UNLOCK(&keytable->lock);

    *keynodep = NULL;
}

isc_result_t
dns_keytable_issecuredomain(dns_keytable_t *keytable, dns_name_t *name,
                isc_boolean_t *wantdnssecp)
{
    isc_result_t result;
    void *data;

    /*
     * Is 'name' at or beneath a trusted key?
     */

    REQUIRE(VALID_KEYTABLE(keytable));
    REQUIRE(dns_name_isabsolute(name));
    REQUIRE(wantdnssecp != NULL);

    RWLOCK(&keytable->rwlock, isc_rwlocktype_read);

    data = NULL;
    result = dns_rbt_findname(keytable->table, name, 0, NULL, &data);

    if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
        INSIST(data != NULL);
        *wantdnssecp = ISC_TRUE;
        result = ISC_R_SUCCESS;
    } else if (result == ISC_R_NOTFOUND) {
        *wantdnssecp = ISC_FALSE;
        result = ISC_R_SUCCESS;
    }

    RWUNLOCK(&keytable->rwlock, isc_rwlocktype_read);

    return (result);
}

dst_key_t *
dns_keynode_key(dns_keynode_t *keynode) {

    /*
     * Get the DST key associated with keynode.
     */

    REQUIRE(VALID_KEYNODE(keynode));

    return (keynode->key);
}