/src/bind9/lib/dns/deleg.c

Source
/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/netaddr.h>
#include <isc/sieve.h>
#include <isc/stdtime.h>
#include <isc/urcu.h>
#include <isc/uv.h>

#include <dns/deleg.h>
#include <dns/name.h>
#include <dns/qp.h>
#include <dns/view.h>

#include "probes-dns.h"

#define DELEGDB_NODE_MAGIC   ISC_MAGIC('D', 'e', 'G', 'N')
#define VALID_DELEGDB_NODE(node) ISC_MAGIC_VALID(node, DELEGDB_NODE_MAGIC)

#define DELEGDB_MAGIC   ISC_MAGIC('D', 'e', 'G', 'D')
#define VALID_DELEGDB(db) ISC_MAGIC_VALID(db, DELEGDB_MAGIC)

#define DELEGDB_MINSIZE (1024 * 1024) /* 1MiB */

typedef struct delegdb_node delegdb_node_t;

typedef struct qplru {
  isc_mem_t *mctx;
  isc_refcount_t references;
  dns_qpmulti_t *nodes;
  ISC_SIEVE(delegdb_node_t) lru;
  struct rcu_head rcu_head;
} qplru_t;

static void
qplru_destroy(qplru_t *qplru);

#ifdef DNS_DELEGDB_NODETRACE
#define qplru_ref(ptr)   qplru__ref(ptr, __func__, __FILE__, __LINE__)
#define qplru_unref(ptr) qplru__unref(ptr, __func__, __FILE__, __LINE__)
#define qplru_attach(ptr, ptrp) \
  qplru__attach(ptr, ptrp, __func__, __FILE__, __LINE__)
#define qplru_detach(ptrp) qplru__detach(ptrp, __func__, __FILE__, __LINE__)
ISC_REFCOUNT_STATIC_TRACE_DECL(qplru);
ISC_REFCOUNT_STATIC_TRACE_IMPL(qplru, qplru_destroy);
#else
ISC_REFCOUNT_STATIC_DECL(qplru);
ISC_REFCOUNT_STATIC_IMPL(qplru, qplru_destroy);
#endif

struct dns_delegdb {
  unsigned int magic;

  /*
   * The DB uses its own memory context in order to easily enforce
   * overmem policies based on allocations made from this memory context.
   */
  isc_mem_t *mctx;
  isc_refcount_t references;

  qplru_t *qplru;

  dns_delegdb_config_t config;
};

static void
qplru_shutdown_rcu(struct rcu_head *rcu_head);

static void
delegdb_destroy(dns_delegdb_t *delegdb) {
  REQUIRE(VALID_DELEGDB(delegdb));

  delegdb->magic = 0;

  qplru_t *qplru = rcu_xchg_pointer(&delegdb->qplru, NULL);
  INSIST(qplru != NULL);

  /*
   * Offload the LRU list node deletion to RCU thread (as well as qptrie
   * deletion).
   */
  call_rcu(&qplru->rcu_head, qplru_shutdown_rcu);

  LIBDNS_DELEGDB_SHUTDOWN(delegdb);

  isc_mem_putanddetach(&delegdb->mctx, delegdb, sizeof(*delegdb));
}

ISC_REFCOUNT_IMPL(dns_delegdb, delegdb_destroy);

struct delegdb_node {
  unsigned int magic;

  qplru_t *qplru;

  isc_refcount_t references;

  /* LRU */
  ISC_LINK(delegdb_node_t) link;
  bool visited;

  /*
   * Used to build a list of nodes to be deleted (when running the
   * delete tree flow).
   */
  ISC_LINK(delegdb_node_t) deadlink;

  /*
   * Immutable node data
   */
  dns_delegset_t *delegset;

  dns_name_t zonecut;
  uint8_t zonecut_buffer[];
};

static size_t
delegdb_node_size(const delegdb_node_t *node) {
  return sizeof(*node) + node->zonecut.length;
}

static void
delegdb_node_destroy(delegdb_node_t *node) {
  REQUIRE(VALID_DELEGDB_NODE(node));
  REQUIRE(DNS_DELEGSET_VALID(node->delegset));

  qplru_t *qplru = node->qplru;

  node->magic = 0;

  dns_delegset_detach(&node->delegset);

  isc_mem_put(qplru->mctx, node, delegdb_node_size(node));

  qplru_detach(&qplru);
}

#ifdef DNS_DELEGDB_NODETRACE
#define delegdb_node_ref(ptr) \
  delegdb_node__ref(ptr, __func__, __FILE__, __LINE__)
#define delegdb_node_unref(ptr) \
  delegdb_node__unref(ptr, __func__, __FILE__, __LINE__)
#define delegdb_node_attach(ptr, ptrp) \
  delegdb_node__attach(ptr, ptrp, __func__, __FILE__, __LINE__)
#define delegdb_node_detach(ptrp) \
  delegdb_node__detach(ptrp, __func__, __FILE__, __LINE__)
ISC_REFCOUNT_STATIC_TRACE_DECL(delegdb_node);
ISC_REFCOUNT_STATIC_TRACE_IMPL(delegdb_node, delegdb_node_destroy);
#else
ISC_REFCOUNT_STATIC_DECL(delegdb_node);
ISC_REFCOUNT_STATIC_IMPL(delegdb_node, delegdb_node_destroy);
#endif

static void
dbnode_attach(ISC_ATTR_UNUSED void *uctx, void *pval,
        ISC_ATTR_UNUSED uint32_t ival) {
  delegdb_node_t *node = pval;

  REQUIRE(VALID_DELEGDB_NODE(node));
  delegdb_node_ref(node);
}

static void
dbnode_detach(ISC_ATTR_UNUSED void *uctx, void *pval,
        ISC_ATTR_UNUSED uint32_t ival) {
  delegdb_node_t *node = pval;

  REQUIRE(VALID_DELEGDB_NODE(node));
  delegdb_node_unref(node);
}

static size_t
makekey(dns_qpkey_t key, void *uctx ISC_ATTR_UNUSED, void *pval,
  uint32_t ival ISC_ATTR_UNUSED) {
  delegdb_node_t *data = pval;
  return dns_qpkey_fromname(key, &data->zonecut, DNS_DBNAMESPACE_NORMAL);
}

static void
triename(ISC_ATTR_UNUSED void *uctx, char *buf, size_t size) {
  (void)strncpy(buf, "delegdb", size);
}

static dns_qpmethods_t qpmethods = { .attach = dbnode_attach,
             .detach = dbnode_detach,
             .makekey = makekey,
             .triename = triename };

void
dns_delegdb_create(dns_delegdb_t **delegdbp) {
  isc_mem_t *mctx = NULL;
  dns_delegdb_t *delegdb = NULL;

  REQUIRE(isc_loop_get(isc_tid()) == isc_loop_main());
  REQUIRE(delegdbp != NULL && *delegdbp == NULL);

  isc_mem_create("dns_delegdb", &mctx);
  isc_mem_setdestroycheck(mctx, true);

  delegdb = isc_mem_get(mctx, sizeof(*delegdb));
  *delegdb = (dns_delegdb_t){ .magic = DELEGDB_MAGIC,
            .mctx = mctx,
            .references = ISC_REFCOUNT_INITIALIZER(1),
            .config = {} };

  qplru_t *qplru = isc_mem_get(mctx, sizeof(*qplru));
  *qplru = (qplru_t){
    .mctx = isc_mem_ref(mctx),
    .references = ISC_REFCOUNT_INITIALIZER(1),
  };

  dns_qpmulti_create(mctx, &qpmethods, &qplru->nodes, &qplru->nodes);
  ISC_SIEVE_INIT(qplru->lru);

  delegdb->qplru = MOVE_OWNERSHIP(qplru);

  LIBDNS_DELEGDB_CREATE(delegdb);

  *delegdbp = delegdb;
}

static void
qplru_destroy(qplru_t *qplru) {
  isc_mem_putanddetach(&qplru->mctx, qplru, sizeof(*qplru));
}

inline static bool
isactive(delegdb_node_t *node, dns_ttl_t now) {
  return node->delegset->expires > now;
}

static void
getparentnode(dns_qpchain_t *chain, delegdb_node_t **node, dns_ttl_t now) {
  size_t len = dns_qpchain_length(chain);

  while (len >= 2) {
    delegdb_node_t *parent = NULL;
    dns_qpchain_node(chain, len - 2, (void **)&parent, NULL);

    if (isactive(parent, now)) {
      *node = parent;
      return;
    }
    len--;
  }

  /*
   * No active proper ancestor was found in the chain.  Signal
   * "no parent" so the caller does not mistake the original
   * matched node for an ancestor.
   */
  *node = NULL;
}

/*
 * NOTE: Caller needs to hold a RCU read critical section.
 */
static isc_result_t
deleg_lookup(dns_delegdb_t *delegdb, dns_qpread_t *qpr, const dns_name_t *name,
       isc_stdtime_t optnow, unsigned int options, dns_name_t *zonecut,
       dns_name_t *deepestzonecut, dns_delegset_t **delegsetp) {
  isc_result_t result = ISC_R_SUCCESS;
  delegdb_node_t *node = NULL;
  isc_stdtime_t now = optnow > 0 ? optnow : isc_stdtime_now();

  dns_qpchain_t chain = {};
  bool above = (options & DNS_DBFIND_ABOVE) != 0;

  REQUIRE(VALID_DELEGDB(delegdb));
  REQUIRE(DNS_NAME_VALID(name));
  REQUIRE(dns_name_hasbuffer(zonecut));
  REQUIRE(deepestzonecut == NULL || dns_name_hasbuffer(deepestzonecut));

  result = dns_qp_lookup(qpr, name, DNS_DBNAMESPACE_NORMAL, NULL, &chain,
             (void **)&node, NULL);

  if (result != ISC_R_SUCCESS && result != DNS_R_PARTIALMATCH) {
    return ISC_R_NOTFOUND;
  }
  INSIST(VALID_DELEGDB_NODE(node));

  if (deepestzonecut != NULL) {
    dns_name_copy(&node->zonecut, deepestzonecut);
  }

  /*
   * Walk up the chain when:
   *  - we have an exact match but the caller asked for DNS_DBFIND_ABOVE
   *    (i.e. the caller wants the deepest *proper* ancestor), or
   *  - the matched node is no longer active and we need to fall
   *    back to the closest still-active ancestor (this applies
   *    equally to exact and partial matches).
   *
   * getparentnode() sets 'node' to NULL when no active ancestor
   * exists in the chain, so we must NULL-check before dereferencing
   * 'node' below.
   */
  if ((result == ISC_R_SUCCESS && above) || !isactive(node, now)) {
    getparentnode(&chain, &node, now);
  }

  if (node != NULL && isactive(node, now)) {
    dns_name_copy(&node->zonecut, zonecut);
    INSIST(node->delegset);
    dns_delegset_attach(node->delegset, delegsetp);
    ISC_SIEVE_MARK(node, visited);
    return ISC_R_SUCCESS;
  }

  /*
   * The expired node will be replaced when the resolver fetches
   * a fresh delegation, so there is no need to schedule explicit
   * cleanup here.  Stale nodes that are never replaced will
   * eventually be evicted by the SIEVE policy under memory
   * pressure.
   */
  return ISC_R_NOTFOUND;
}

isc_result_t
dns_delegdb_lookup(dns_delegdb_t *delegdb, const dns_name_t *name,
       isc_stdtime_t now, unsigned int options, dns_name_t *zonecut,
       dns_name_t *deepestzonecut, dns_delegset_t **delegsetp) {
  isc_result_t result = ISC_R_SHUTTINGDOWN;
  dns_qpread_t qpr = {};
  char namebuf[DNS_NAME_FORMATSIZE];

  if (LIBDNS_DELEGDB_LOOKUP_START_ENABLED() ||
      LIBDNS_DELEGDB_LOOKUP_DONE_ENABLED())
  {
    dns_name_format(name, namebuf, sizeof(namebuf));
  }
  LIBDNS_DELEGDB_LOOKUP_START(delegdb, namebuf);

  dns_qpmulti_query(delegdb->qplru->nodes, &qpr);
  result = deleg_lookup(delegdb, &qpr, name, now, options, zonecut,
            deepestzonecut, delegsetp);
  dns_qpread_destroy(delegdb->qplru->nodes, &qpr);

  LIBDNS_DELEGDB_LOOKUP_DONE(delegdb, namebuf, result);

  return result;
}

void
dns_delegset_allocset(dns_delegdb_t *delegdb, dns_delegset_t **delegsetp) {
  REQUIRE(VALID_DELEGDB(delegdb));
  REQUIRE(delegsetp != NULL && *delegsetp == NULL);

  dns_delegset_t *delegset = isc_mem_get(delegdb->mctx,
                 sizeof(*delegset));
  *delegset = (dns_delegset_t){
    .magic = DNS_DELEGSET_MAGIC,
    .references = ISC_REFCOUNT_INITIALIZER(1),
    .delegs = ISC_LIST_INITIALIZER,
  };
  isc_mem_attach(delegdb->mctx, &delegset->mctx);

  *delegsetp = delegset;
}

void
dns_delegset_allocdeleg(dns_delegset_t *delegset, dns_deleg_type_t type,
      dns_deleg_t **delegp) {
  dns_deleg_t *deleg = NULL;

  REQUIRE(DNS_DELEGSET_VALID(delegset));
  REQUIRE(delegp != NULL && *delegp == NULL);
  REQUIRE(type != DNS_DELEGTYPE_UNDEFINED);

  deleg = isc_mem_get(delegset->mctx, sizeof(*deleg));
  *deleg = (dns_deleg_t){ .addresses = ISC_LIST_INITIALIZER,
        .names = ISC_LIST_INITIALIZER,
        .type = type,
        .link = ISC_LINK_INITIALIZER };

  ISC_LIST_APPEND(delegset->delegs, deleg, link);
  *delegp = deleg;
}

void
dns_delegset_freedeleg(dns_delegset_t *delegset, dns_deleg_t **delegp) {
  REQUIRE(DNS_DELEGSET_VALID(delegset));
  REQUIRE(delegp != NULL && *delegp != NULL);
  REQUIRE(ISC_LIST_EMPTY((*delegp)->addresses));
  REQUIRE(ISC_LIST_EMPTY((*delegp)->names));

  dns_deleg_t *deleg = *delegp;
  *delegp = NULL;

  ISC_LIST_UNLINK(delegset->delegs, deleg, link);

  isc_mem_put(delegset->mctx, deleg, sizeof(*deleg));
}

void
dns_delegset_addaddr(dns_delegset_t *delegset, dns_deleg_t *deleg,
         const isc_netaddr_t *addr) {
  isc_netaddrlink_t *addrlink = NULL;

  REQUIRE(DNS_DELEGSET_VALID(delegset));
  REQUIRE(deleg != NULL);
  REQUIRE(addr != NULL);
  REQUIRE(deleg->type == DNS_DELEGTYPE_DELEG_ADDRESSES ||
    deleg->type == DNS_DELEGTYPE_NS_GLUES);

  addrlink = isc_mem_get(delegset->mctx, sizeof(*addrlink));
  *addrlink = (isc_netaddrlink_t){ .addr = *addr,
           .link = ISC_LINK_INITIALIZER };

  ISC_LIST_APPEND(deleg->addresses, addrlink, link);
}

static void
addname(dns_delegset_t *delegset, dns_namelist_t *list,
  const dns_name_t *name) {
  dns_name_t *clone = NULL;

  REQUIRE(DNS_DELEGSET_VALID(delegset));
  REQUIRE(DNS_NAME_VALID(name));

  clone = isc_mem_get(delegset->mctx, sizeof(*clone));
  dns_name_init(clone);
  dns_name_dup(name, delegset->mctx, clone);
  ISC_LIST_APPEND(*list, clone, link);
}

void
dns_delegset_adddelegparam(dns_delegset_t *delegset, dns_deleg_t *deleg,
         const dns_name_t *name) {
  REQUIRE(deleg != NULL);
  REQUIRE(deleg->type == DNS_DELEGTYPE_DELEG_PARAMS);
  addname(delegset, &deleg->names, name);
}

void
dns_delegset_addns(dns_delegset_t *delegset, dns_deleg_t *deleg,
       const dns_name_t *name) {
  REQUIRE(deleg != NULL);

  REQUIRE(deleg->type == DNS_DELEGTYPE_DELEG_NAMES ||
    deleg->type == DNS_DELEGTYPE_NS_NAMES);
  addname(delegset, &deleg->names, name);
}

static size_t
delegset_size(dns_delegset_t *delegset);

static void
delegdb_cleanup(dns_delegdb_t *delegdb, dns_qp_t *qp, size_t requested) {
  delegdb_node_t *node = NULL;
  size_t reclaimed = 0;

  if (!isc_mem_isovermem(delegdb->mctx)) {
    return;
  }

  LIBDNS_DELEGDB_CLEANUP_START(delegdb, (int)requested);

  while (reclaimed < requested) {
    node = ISC_SIEVE_NEXT(delegdb->qplru->lru, visited, link);

    if (node == NULL) {
      break;
    }
    reclaimed += delegdb_node_size(node) +
           delegset_size(node->delegset);

    if (LIBDNS_DELEGDB_EVICT_ENABLED()) {
      char namebuf[DNS_NAME_FORMATSIZE];
      dns_name_format(&node->zonecut, namebuf,
          sizeof(namebuf));
      LIBDNS_DELEGDB_EVICT(delegdb, node, namebuf);
    }

    delegdb_node_t *old_node = NULL;
    isc_result_t result = dns_qp_deletename(
      qp, &node->zonecut, DNS_DBNAMESPACE_NORMAL,
      (void *)&old_node, NULL);
    if (result == ISC_R_SUCCESS) {
      ISC_SIEVE_UNLINK(delegdb->qplru->lru, old_node, link);
      delegdb_node_detach(&old_node);
    }
  }

  LIBDNS_DELEGDB_CLEANUP_DONE(delegdb, (int)reclaimed);
}

static size_t
delegset_size(dns_delegset_t *delegset) {
  size_t sz = 0;

  sz += sizeof(*delegset);
  ISC_LIST_FOREACH(delegset->delegs, deleg, link) {
    sz += sizeof(*deleg);
    ISC_LIST_FOREACH(deleg->addresses, address, link) {
      sz += sizeof(*address);
    }
    ISC_LIST_FOREACH(deleg->names, name, link) {
      sz += sizeof(*name) + dns_name_size(name);
    }
  }

  return sz;
}

static dns_ttl_t
normalize_ttl(dns_delegdb_t *delegdb, dns_ttl_t ttl) {
  dns_ttl_t minttl = delegdb->config.minttl;
  dns_ttl_t maxttl = delegdb->config.maxttl;

  if (minttl > 0 && ttl < minttl) {
    return minttl;
  }

  if (maxttl > 0 && ttl > maxttl) {
    return maxttl;
  }

  /*
   * Even if the min ttl is disabled, it doesn't make sense to add an
   * already expired delegation. So give it at least one second.
   */
  return ttl == 0 ? 1 : ttl;
}

static size_t
delegdb_node_prepare(dns_delegdb_t *delegdb, isc_stdtime_t now, dns_ttl_t ttl,
         const dns_name_t *zonecut, dns_delegset_t *delegset,
         delegdb_node_t **nodep) {
  ttl = normalize_ttl(delegdb, ttl);
  delegset->expires = ttl + now;

  isc_region_t zonecut_r = { 0 };
  dns_name_toregion(zonecut, &zonecut_r);

  delegdb_node_t *node = isc_mem_get(delegdb->qplru->mctx,
             sizeof(*node) + zonecut_r.length);
  *node = (delegdb_node_t){

    .magic = DELEGDB_NODE_MAGIC,
    .references = ISC_REFCOUNT_INITIALIZER(1),
    .link = ISC_LINK_INITIALIZER,
    .deadlink = ISC_LINK_INITIALIZER,
    .zonecut = DNS_NAME_INITEMPTY,
    .qplru = qplru_ref(delegdb->qplru),
  };
  dns_delegset_attach(delegset, &node->delegset);

  memmove(node->zonecut_buffer, zonecut_r.base, zonecut_r.length);
  zonecut_r.base = node->zonecut_buffer;
  dns_name_fromregion(&node->zonecut, &zonecut_r);

  *nodep = node;

  return delegdb_node_size(node);
}

isc_result_t
dns_delegset_insert(dns_delegdb_t *delegdb, const dns_name_t *zonecut,
        dns_ttl_t ttl, dns_delegset_t *delegset) {
  isc_result_t result;
  delegdb_node_t *node = NULL;
  dns_qp_t *qp = NULL;
  dns_qpread_t qpr = {};
  isc_stdtime_t now = isc_stdtime_now();
  char zonecutbuf[DNS_NAME_FORMATSIZE];

  REQUIRE(VALID_DELEGDB(delegdb));
  REQUIRE(DNS_NAME_VALID(zonecut));
  REQUIRE(DNS_DELEGSET_VALID(delegset));

  /*
   * Only delegset allocated by the delegdb memory context can be added in
   * the delegdb. This exclude transient delegset built from rdataset (see
   * dns_delegset_fromrdataset()).
   */
  REQUIRE(delegset->mctx == delegdb->mctx);

  if (LIBDNS_DELEGDB_INSERT_START_ENABLED() ||
      LIBDNS_DELEGDB_INSERT_DONE_ENABLED())
  {
    dns_name_format(zonecut, zonecutbuf, sizeof(zonecutbuf));
  }
  LIBDNS_DELEGDB_INSERT_START(delegdb, zonecutbuf);

  /*
   * First, check (without write txn) if the node already exists and is
   * still valid.
   */
  dns_qpmulti_query(delegdb->qplru->nodes, &qpr);
  result = dns_qp_lookup(&qpr, zonecut, DNS_DBNAMESPACE_NORMAL, NULL,
             NULL, (void **)&node, NULL);
  if (result == ISC_R_SUCCESS) {
    INSIST(VALID_DELEGDB_NODE(node));
    if (node->delegset->expires > now) {
      dns_qpread_destroy(delegdb->qplru->nodes, &qpr);
      CLEANUP(ISC_R_EXISTS);
    }
  }
  dns_qpread_destroy(delegdb->qplru->nodes, &qpr);

  /*
   * We're about to add a new delegation, check for state of overmem, and
   * clean up expired/least recently used delegation, then allocate and
   * initialize a new node.
   */
  size_t requested = delegdb_node_prepare(delegdb, now, ttl, zonecut,
            delegset, &node) +
         delegset_size(delegset);

  /*
   * Add the node in the DB
   */
  dns_qpmulti_write(delegdb->qplru->nodes, &qp);

  delegdb_cleanup(delegdb, qp, requested);

  if (result == ISC_R_SUCCESS) {
    delegdb_node_t *old_node = NULL;
    result = dns_qp_deletename(qp, zonecut, DNS_DBNAMESPACE_NORMAL,
             (void *)&old_node, NULL);
    if (result == ISC_R_SUCCESS) {
      ISC_SIEVE_UNLINK(delegdb->qplru->lru, old_node, link);
      delegdb_node_detach(&old_node);
    }
  }

  result = dns_qp_insert(qp, node, 0);
  if (result != ISC_R_SUCCESS) {
    /*
     * Someone else added the node before (and there was no node to
     * delete).
     */

    delegdb_node_unref(node);

    /*
     * Since not using an update (but write) transaction,
     * _rollback() won't work here.
     */
    dns_qpmulti_commit(delegdb->qplru->nodes, &qp);
    CLEANUP(ISC_R_EXISTS);
  }

  /*
   * The new delegation is added, and can be referenced by SIEVE
   */
  delegdb_node_ref(node);
  ISC_SIEVE_INSERT(delegdb->qplru->lru, node, link);

  delegdb_node_unref(node);
  dns_qp_compact(qp, DNS_QPGC_MAYBE);
  dns_qpmulti_commit(delegdb->qplru->nodes, &qp);

cleanup:
  LIBDNS_DELEGDB_INSERT_DONE(delegdb, zonecutbuf, result);

  return result;
}

static void
delegset_destroy(dns_delegset_t *delegset) {
  REQUIRE(DNS_DELEGSET_VALID(delegset));

  delegset->magic = 0;
  ISC_LIST_FOREACH(delegset->delegs, deleg, link) {
    deleg->type = DNS_DELEGTYPE_UNDEFINED;

    ISC_LIST_UNLINK(delegset->delegs, deleg, link);

    ISC_LIST_FOREACH(deleg->addresses, address, link) {
      ISC_LIST_UNLINK(deleg->addresses, address, link);
      isc_mem_put(delegset->mctx, address, sizeof(*address));
    }

    ISC_LIST_FOREACH(deleg->names, nameserver, link) {
      ISC_LIST_UNLINK(deleg->names, nameserver, link);
      dns_name_free(nameserver, delegset->mctx);
      isc_mem_put(delegset->mctx, nameserver,
            sizeof(*nameserver));
    }

    isc_mem_put(delegset->mctx, deleg, sizeof(*deleg));
  }

  isc_mem_putanddetach(&delegset->mctx, delegset, sizeof(*delegset));
}
ISC_REFCOUNT_IMPL(dns_delegset, delegset_destroy);

static void
tostring_namelist(dns_namelist_t *namelist, const char *id, FILE *fp) {
  if (!ISC_LIST_EMPTY(*namelist)) {
    fprintf(fp, " %s=", id);
    ISC_LIST_FOREACH(*namelist, name, link) {
      isc_buffer_t nameb;
      char bdata[DNS_NAME_FORMATSIZE] = { 0 };

      isc_buffer_init(&nameb, bdata, sizeof(bdata));
      dns_name_totext(name, 0, &nameb);
      fprintf(fp, "%s", bdata);

      if (name != ISC_LIST_TAIL(*namelist)) {
        fprintf(fp, ",");
      }
    }
  }
}

static void
deleg_tostring_addresses(dns_deleg_t *deleg, FILE *fp) {
  bool hasv4 = false;
  bool hasv6 = false;

  ISC_LIST_FOREACH(deleg->addresses, address, link) {
    if (address->addr.family == AF_INET) {
      hasv4 = true;
    } else {
      hasv6 = true;
    }
  }

  if (hasv4) {
    bool first = true;

    fprintf(fp, " server-ipv4=");
    ISC_LIST_FOREACH(deleg->addresses, address, link) {
      char addrstr[] = "255.255.255.255";

      if (address->addr.family == AF_INET6) {
        continue;
      }

      if (!first) {
        fprintf(fp, ",");
      }
      first = false;

      inet_ntop(AF_INET, &address->addr.type, addrstr,
          sizeof(addrstr));
      fprintf(fp, "%s", addrstr);
    }
  }

  if (hasv6) {
    bool first = true;

    fprintf(fp, " server-ipv6=");
    ISC_LIST_FOREACH(deleg->addresses, address, link) {
      char addrstr[INET6_ADDRSTRLEN];

      if (address->addr.family == AF_INET) {
        continue;
      }

      if (!first) {
        fprintf(fp, ",");
      }
      first = false;

      inet_ntop(AF_INET6, &address->addr.type, addrstr,
          sizeof(addrstr));
      fprintf(fp, "%s", addrstr);
    }
  }
}

static void
delegset_tostring(const dns_name_t *zonecut, dns_delegset_t *delegset,
      isc_stdtime_t now, bool expired, FILE *fp) {
  ISC_LIST_FOREACH(delegset->delegs, deleg, link) {
    isc_buffer_t zonecutb;
    char bdata[DNS_NAME_FORMATSIZE];
    dns_ttl_t ttl = 0;

    if (delegset->expires > now) {
      ttl = delegset->expires - now;
    } else {
      INSIST(expired);
    }

    isc_buffer_init(&zonecutb, bdata, sizeof(bdata));
    dns_name_totext(zonecut, 0, &zonecutb);
    fprintf(fp, "%s %u DELEG", bdata, ttl);

    if (deleg->type == DNS_DELEGTYPE_DELEG_ADDRESSES ||
        deleg->type == DNS_DELEGTYPE_NS_GLUES)
    {
      deleg_tostring_addresses(deleg, fp);
    } else if (deleg->type == DNS_DELEGTYPE_DELEG_NAMES ||
         deleg->type == DNS_DELEGTYPE_NS_NAMES)
    {
      tostring_namelist(&deleg->names, "server-name", fp);
    } else if (deleg->type == DNS_DELEGTYPE_DELEG_PARAMS) {
      tostring_namelist(&deleg->names, "include-delegparam",
            fp);
    } else {
      UNREACHABLE();
    }

    fprintf(fp, "\n");
  }
}

void
dns_delegdb_dump(dns_delegdb_t *delegdb, bool expired, FILE *fp) {
  REQUIRE(VALID_DELEGDB(delegdb));
  REQUIRE(fp != NULL);

  dns_qpiter_t it;
  dns_qpread_t qpr = {};
  delegdb_node_t *node = NULL;
  isc_stdtime_t now = isc_stdtime_now();

  dns_qpmulti_query(delegdb->qplru->nodes, &qpr);

  dns_qpiter_init(&qpr, &it);
  while (dns_qpiter_next(&it, (void **)&node, NULL) == ISC_R_SUCCESS) {
    if (!expired && !isactive(node, now)) {
      continue;
    }

    delegset_tostring(&node->zonecut, node->delegset, now, expired,
          fp);
  }

  dns_qpread_destroy(delegdb->qplru->nodes, &qpr);
}

void
dns_delegset_fromnsrdataset(isc_mem_t *mctx, dns_rdataset_t *rdataset,
          dns_delegset_t **delegsetp) {
  dns_delegset_t *delegset = NULL;
  dns_deleg_t *deleg = NULL;

  if (rdataset == NULL || !dns_rdataset_isassociated(rdataset) ||
      delegsetp == NULL || *delegsetp != NULL)
  {
    return;
  }

  REQUIRE(rdataset->type == dns_rdatatype_ns);

  delegset = isc_mem_get(mctx, sizeof(*delegset));
  *delegset = (dns_delegset_t){
    .magic = DNS_DELEGSET_MAGIC,
    .mctx = isc_mem_ref(mctx),
    .references = ISC_REFCOUNT_INITIALIZER(1),
    .delegs = ISC_LIST_INITIALIZER,
    .expires = rdataset->ttl + isc_stdtime_now(),
    .staticstub = rdataset->attributes.staticstub
  };

  deleg = isc_mem_get(delegset->mctx, sizeof(*deleg));
  *deleg = (dns_deleg_t){ .addresses = ISC_LIST_INITIALIZER,
        .names = ISC_LIST_INITIALIZER,
        .type = DNS_DELEGTYPE_NS_NAMES,
        .link = ISC_LINK_INITIALIZER };
  ISC_LIST_APPEND(delegset->delegs, deleg, link);

  DNS_RDATASET_FOREACH(rdataset) {
    dns_rdata_t rdata = DNS_RDATA_INIT;
    dns_rdata_ns_t ns;

    dns_rdataset_current(rdataset, &rdata);
    dns_rdata_tostruct(&rdata, &ns, NULL);
    dns_delegset_addns(delegset, deleg, &ns.name);
  }

  *delegsetp = delegset;
}

static isc_result_t
deleg_deletetree(qplru_t *qplru, dns_qp_t *qp, const dns_name_t *name) {
  isc_result_t result;
  delegdb_node_t *node = NULL;
  dns_qpiter_t it;
  ISC_LIST(delegdb_node_t) deadnodes = ISC_LIST_INITIALIZER;

  result = dns_qp_lookup(qp, name, DNS_DBNAMESPACE_NORMAL, &it, NULL,
             (void **)&node, NULL);
  if (result != ISC_R_SUCCESS) {
    goto out;
  }

  INSIST(VALID_DELEGDB_NODE(node));
  do {
    /*
     * Because QP doesn't allow deleting a node while using the
     * iterator, the approach is different than `deleg_deletenode()`
     * here. Instead of removing the node immediately, we add it
     * into a list that we'll go through after, then delete each
     * node.
     */
    ISC_LIST_APPEND(deadnodes, node, deadlink);

    result = dns_qpiter_next(&it, (void **)&node, NULL);
    if (result == ISC_R_NOMORE) {
      result = ISC_R_SUCCESS;
      break;
    }

    INSIST(VALID_DELEGDB_NODE(node));
    if (!dns_name_issubdomain(&node->zonecut, name)) {
      break;
    }
  } while (result == ISC_R_SUCCESS);

out:
  if (ISC_LIST_EMPTY(deadnodes)) {
    result = ISC_R_NOTFOUND;
  } else {
    /*
     * Let's actually delete the deadnodes!
     */
    ISC_LIST_FOREACH(deadnodes, deadnode, deadlink) {
      delegdb_node_t *old_node = NULL;
      result = dns_qp_deletename(qp, &deadnode->zonecut,
               DNS_DBNAMESPACE_NORMAL,
               (void *)&old_node, NULL);
      INSIST(result == ISC_R_SUCCESS);
      INSIST(old_node == deadnode);
      ISC_SIEVE_UNLINK(qplru->lru, old_node, link);
      delegdb_node_detach(&old_node);
    }
  }

  return result;
}

static isc_result_t
deleg_deletenode(qplru_t *qplru, dns_qp_t *qp, const dns_name_t *name) {
  delegdb_node_t *old_node = NULL;
  isc_result_t result = dns_qp_deletename(
    qp, name, DNS_DBNAMESPACE_NORMAL, (void *)&old_node, NULL);
  if (result == ISC_R_SUCCESS) {
    ISC_SIEVE_UNLINK(qplru->lru, old_node, link);
    delegdb_node_detach(&old_node);
  }

  return result;
}

isc_result_t
dns_delegdb_delete(dns_delegdb_t *delegdb, const dns_name_t *name, bool tree) {
  REQUIRE(VALID_DELEGDB(delegdb));
  REQUIRE(DNS_NAME_VALID(name));

  dns_qp_t *qp = NULL;
  isc_result_t result = ISC_R_SHUTTINGDOWN;
  char namebuf[DNS_NAME_FORMATSIZE];

  if (LIBDNS_DELEGDB_DELETE_ENABLED()) {
    dns_name_format(name, namebuf, sizeof(namebuf));
  }

  dns_qpmulti_write(delegdb->qplru->nodes, &qp);
  if (tree) {
    result = deleg_deletetree(delegdb->qplru, qp, name);
  } else {
    result = deleg_deletenode(delegdb->qplru, qp, name);
  }
  if (result == ISC_R_SUCCESS) {
    dns_qp_compact(qp, DNS_QPGC_MAYBE);
  }
  dns_qpmulti_commit(delegdb->qplru->nodes, &qp);

  LIBDNS_DELEGDB_DELETE(delegdb, namebuf, (int)tree, result);

  return result;
}

static void
qplru_shutdown_rcu(struct rcu_head *rcu_head) {
  qplru_t *qplru = caa_container_of(rcu_head, qplru_t, rcu_head);

  ISC_SIEVE_FOREACH(qplru->lru, node, link) {
    ISC_SIEVE_UNLINK(qplru->lru, node, link);
    delegdb_node_detach(&node);
  }

  dns_qpmulti_destroy(&qplru->nodes);

  qplru_detach(&qplru);
}

static void
delegdb_setsize(dns_delegdb_t *delegdb, size_t size) {
  size_t lowater;
  size_t hiwater;

  REQUIRE(VALID_DELEGDB(delegdb));

  if (size != 0 && size < DELEGDB_MINSIZE) {
    size = DELEGDB_MINSIZE;
  }

  hiwater = size - (size >> 3); /* Approximately 7/8ths. */
  lowater = size - (size >> 2); /* Approximately 3/4ths. */

  if (size == 0 || hiwater == 0 || lowater == 0) {
    isc_mem_clearwater(delegdb->mctx);

    /*
     * TODO: Is it worth a warning if size > 0? Sounds like
     * implicit overmem bypass, so the user should be warned...
     */
  } else {
    isc_mem_setwater(delegdb->mctx, hiwater, lowater);
  }
}

dns_delegdb_config_t
dns_delegdb_getconfig(dns_delegdb_t *delegdb) {
  REQUIRE(VALID_DELEGDB(delegdb));
  return delegdb->config;
}

void
dns_delegdb_setconfig(dns_delegdb_t *delegdb,
          const dns_delegdb_config_t *config) {
  REQUIRE(isc_loop_get(isc_tid()) == isc_loop_main());
  REQUIRE(VALID_DELEGDB(delegdb));

  delegdb->config = *config;

  delegdb_setsize(delegdb, delegdb->config.dbsize);
}

Coverage Report

Created: 2026-07-30 06:31