-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Copyright 2014 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-
-#include "list.h"
-
-#include "resolved-dns-zone.h"
-#include "resolved-dns-domain.h"
-#include "resolved-dns-packet.h"
-
-/* Never allow more than 1K entries */
-#define ZONE_MAX 1024
-
-void dns_zone_item_probe_stop(DnsZoneItem *i) {
- DnsTransaction *t;
- assert(i);
-
- if (!i->probe_transaction)
- return;
-
- t = i->probe_transaction;
- i->probe_transaction = NULL;
-
- set_remove(t->zone_items, i);
- dns_transaction_gc(t);
-}
-
-static void dns_zone_item_free(DnsZoneItem *i) {
- if (!i)
- return;
-
- dns_zone_item_probe_stop(i);
- dns_resource_record_unref(i->rr);
-
- free(i);
-}
-
-DEFINE_TRIVIAL_CLEANUP_FUNC(DnsZoneItem*, dns_zone_item_free);
-
-static void dns_zone_item_remove_and_free(DnsZone *z, DnsZoneItem *i) {
- DnsZoneItem *first;
-
- assert(z);
-
- if (!i)
- return;
-
- first = hashmap_get(z->by_key, i->rr->key);
- LIST_REMOVE(by_key, first, i);
- if (first)
- assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0);
- else
- hashmap_remove(z->by_key, i->rr->key);
-
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
- LIST_REMOVE(by_name, first, i);
- if (first)
- assert_se(hashmap_replace(z->by_name, DNS_RESOURCE_KEY_NAME(first->rr->key), first) >= 0);
- else
- hashmap_remove(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
-
- dns_zone_item_free(i);
-}
-
-void dns_zone_flush(DnsZone *z) {
- DnsZoneItem *i;
-
- assert(z);
-
- while ((i = hashmap_first(z->by_key)))
- dns_zone_item_remove_and_free(z, i);
-
- assert(hashmap_size(z->by_key) == 0);
- assert(hashmap_size(z->by_name) == 0);
-
- hashmap_free(z->by_key);
- z->by_key = NULL;
-
- hashmap_free(z->by_name);
- z->by_name = NULL;
-}
-
-static DnsZoneItem* dns_zone_get(DnsZone *z, DnsResourceRecord *rr) {
- DnsZoneItem *i;
-
- assert(z);
- assert(rr);
-
- LIST_FOREACH(by_key, i, hashmap_get(z->by_key, rr->key))
- if (dns_resource_record_equal(i->rr, rr) > 0)
- return i;
-
- return NULL;
-}
-
-void dns_zone_remove_rr(DnsZone *z, DnsResourceRecord *rr) {
- DnsZoneItem *i;
-
- assert(z);
- assert(rr);
-
- i = dns_zone_get(z, rr);
- if (i)
- dns_zone_item_remove_and_free(z, i);
-}
-
-static int dns_zone_init(DnsZone *z) {
- int r;
-
- assert(z);
-
- r = hashmap_ensure_allocated(&z->by_key, &dns_resource_key_hash_ops);
- if (r < 0)
- return r;
-
- r = hashmap_ensure_allocated(&z->by_name, &dns_name_hash_ops);
- if (r < 0)
- return r;
-
- return 0;
-}
-
-static int dns_zone_link_item(DnsZone *z, DnsZoneItem *i) {
- DnsZoneItem *first;
- int r;
-
- first = hashmap_get(z->by_key, i->rr->key);
- if (first) {
- LIST_PREPEND(by_key, first, i);
- assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0);
- } else {
- r = hashmap_put(z->by_key, i->rr->key, i);
- if (r < 0)
- return r;
- }
-
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
- if (first) {
- LIST_PREPEND(by_name, first, i);
- assert_se(hashmap_replace(z->by_name, DNS_RESOURCE_KEY_NAME(first->rr->key), first) >= 0);
- } else {
- r = hashmap_put(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key), i);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-static int dns_zone_item_probe_start(DnsZoneItem *i) {
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
- _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
- DnsTransaction *t;
- int r;
-
- assert(i);
-
- if (i->probe_transaction)
- return 0;
-
- key = dns_resource_key_new(i->rr->key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(i->rr->key));
- if (!key)
- return -ENOMEM;
-
- question = dns_question_new(1);
- if (!question)
- return -ENOMEM;
-
- r = dns_question_add(question, key);
- if (r < 0)
- return r;
-
- t = dns_scope_find_transaction(i->scope, question, false);
- if (!t) {
- r = dns_transaction_new(&t, i->scope, question);
- if (r < 0)
- return r;
- }
-
- r = set_ensure_allocated(&t->zone_items, NULL);
- if (r < 0)
- goto gc;
-
- r = set_put(t->zone_items, i);
- if (r < 0)
- goto gc;
-
- i->probe_transaction = t;
-
- if (t->state == DNS_TRANSACTION_NULL) {
-
- i->block_ready++;
- r = dns_transaction_go(t);
- i->block_ready--;
-
- if (r < 0) {
- dns_zone_item_probe_stop(i);
- return r;
- }
- }
-
- dns_zone_item_ready(i);
-
- return 0;
-
-gc:
- dns_transaction_gc(t);
- return r;
-}
-
-int dns_zone_put(DnsZone *z, DnsScope *s, DnsResourceRecord *rr, bool probe) {
- _cleanup_(dns_zone_item_freep) DnsZoneItem *i = NULL;
- DnsZoneItem *existing;
- int r;
-
- assert(z);
- assert(s);
- assert(rr);
-
- if (rr->key->class == DNS_CLASS_ANY)
- return -EINVAL;
- if (rr->key->type == DNS_TYPE_ANY)
- return -EINVAL;
-
- existing = dns_zone_get(z, rr);
- if (existing)
- return 0;
-
- r = dns_zone_init(z);
- if (r < 0)
- return r;
-
- i = new0(DnsZoneItem, 1);
- if (!i)
- return -ENOMEM;
-
- i->scope = s;
- i->rr = dns_resource_record_ref(rr);
- i->probing_enabled = probe;
-
- r = dns_zone_link_item(z, i);
- if (r < 0)
- return r;
-
- if (probe) {
- DnsZoneItem *first, *j;
- bool established = false;
-
- /* Check if there's already an RR with the same name
- * established. If so, it has been probed already, and
- * we don't ned to probe again. */
-
- LIST_FIND_HEAD(by_name, i, first);
- LIST_FOREACH(by_name, j, first) {
- if (i == j)
- continue;
-
- if (j->state == DNS_ZONE_ITEM_ESTABLISHED)
- established = true;
- }
-
- if (established)
- i->state = DNS_ZONE_ITEM_ESTABLISHED;
- else {
- i->state = DNS_ZONE_ITEM_PROBING;
-
- r = dns_zone_item_probe_start(i);
- if (r < 0) {
- dns_zone_item_remove_and_free(z, i);
- i = NULL;
- return r;
- }
- }
- } else
- i->state = DNS_ZONE_ITEM_ESTABLISHED;
-
- i = NULL;
- return 0;
-}
-
-int dns_zone_lookup(DnsZone *z, DnsQuestion *q, DnsAnswer **ret_answer, DnsAnswer **ret_soa, bool *ret_tentative) {
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
- unsigned i, n_answer = 0, n_soa = 0;
- bool tentative = true;
- int r;
-
- assert(z);
- assert(q);
- assert(ret_answer);
- assert(ret_soa);
-
- if (q->n_keys <= 0) {
- *ret_answer = NULL;
- *ret_soa = NULL;
-
- if (ret_tentative)
- *ret_tentative = false;
-
- return 0;
- }
-
- /* First iteration, count what we have */
- for (i = 0; i < q->n_keys; i++) {
- DnsZoneItem *j, *first;
-
- if (q->keys[i]->type == DNS_TYPE_ANY ||
- q->keys[i]->class == DNS_CLASS_ANY) {
- bool found = false, added = false;
- int k;
-
- /* If this is a generic match, then we have to
- * go through the list by the name and look
- * for everything manually */
-
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
- LIST_FOREACH(by_name, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- found = true;
-
- k = dns_resource_key_match_rr(q->keys[i], j->rr);
- if (k < 0)
- return k;
- if (k > 0) {
- n_answer++;
- added = true;
- }
-
- }
-
- if (found && !added)
- n_soa++;
-
- } else {
- bool found = false;
-
- /* If this is a specific match, then look for
- * the right key immediately */
-
- first = hashmap_get(z->by_key, q->keys[i]);
- LIST_FOREACH(by_key, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- found = true;
- n_answer++;
- }
-
- if (!found) {
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
- LIST_FOREACH(by_name, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- n_soa++;
- break;
- }
- }
- }
- }
-
- if (n_answer <= 0 && n_soa <= 0) {
- *ret_answer = NULL;
- *ret_soa = NULL;
-
- if (ret_tentative)
- *ret_tentative = false;
-
- return 0;
- }
-
- if (n_answer > 0) {
- answer = dns_answer_new(n_answer);
- if (!answer)
- return -ENOMEM;
- }
-
- if (n_soa > 0) {
- soa = dns_answer_new(n_soa);
- if (!soa)
- return -ENOMEM;
- }
-
- /* Second iteration, actually add the RRs to the answers */
- for (i = 0; i < q->n_keys; i++) {
- DnsZoneItem *j, *first;
-
- if (q->keys[i]->type == DNS_TYPE_ANY ||
- q->keys[i]->class == DNS_CLASS_ANY) {
- bool found = false, added = false;
- int k;
-
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
- LIST_FOREACH(by_name, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- found = true;
-
- if (j->state != DNS_ZONE_ITEM_PROBING)
- tentative = false;
-
- k = dns_resource_key_match_rr(q->keys[i], j->rr);
- if (k < 0)
- return k;
- if (k > 0) {
- r = dns_answer_add(answer, j->rr);
- if (r < 0)
- return r;
-
- added = true;
- }
- }
-
- if (found && !added) {
- r = dns_answer_add_soa(soa, DNS_RESOURCE_KEY_NAME(q->keys[i]), LLMNR_DEFAULT_TTL);
- if (r < 0)
- return r;
- }
- } else {
- bool found = false;
-
- first = hashmap_get(z->by_key, q->keys[i]);
- LIST_FOREACH(by_key, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- found = true;
-
- if (j->state != DNS_ZONE_ITEM_PROBING)
- tentative = false;
-
- r = dns_answer_add(answer, j->rr);
- if (r < 0)
- return r;
- }
-
- if (!found) {
- bool add_soa = false;
-
- first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
- LIST_FOREACH(by_name, j, first) {
- if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING))
- continue;
-
- if (j->state != DNS_ZONE_ITEM_PROBING)
- tentative = false;
-
- add_soa = true;
- }
-
- if (add_soa) {
- r = dns_answer_add_soa(soa, DNS_RESOURCE_KEY_NAME(q->keys[i]), LLMNR_DEFAULT_TTL);
- if (r < 0)
- return r;
- }
- }
- }
- }
-
- *ret_answer = answer;
- answer = NULL;
-
- *ret_soa = soa;
- soa = NULL;
-
- if (ret_tentative)
- *ret_tentative = tentative;
-
- return 1;
-}
-
-void dns_zone_item_conflict(DnsZoneItem *i) {
- _cleanup_free_ char *pretty = NULL;
-
- assert(i);
-
- if (!IN_SET(i->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_VERIFYING, DNS_ZONE_ITEM_ESTABLISHED))
- return;
-
- dns_resource_record_to_string(i->rr, &pretty);
- log_info("Detected conflict on %s", strna(pretty));
-
- dns_zone_item_probe_stop(i);
-
- /* Withdraw the conflict item */
- i->state = DNS_ZONE_ITEM_WITHDRAWN;
-
- /* Maybe change the hostname */
- if (dns_name_equal(i->scope->manager->hostname, DNS_RESOURCE_KEY_NAME(i->rr->key)) > 0)
- manager_next_hostname(i->scope->manager);
-}
-
-void dns_zone_item_ready(DnsZoneItem *i) {
- _cleanup_free_ char *pretty = NULL;
-
- assert(i);
- assert(i->probe_transaction);
-
- if (i->block_ready > 0)
- return;
-
- if (IN_SET(i->probe_transaction->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING))
- return;
-
- if (i->probe_transaction->state == DNS_TRANSACTION_SUCCESS) {
- bool we_lost = false;
-
- /* The probe got a successful reply. If we so far
- * weren't established we just give up. If we already
- * were established, and the peer has the
- * lexicographically larger IP address we continue
- * and defend it. */
-
- if (!IN_SET(i->state, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) {
- log_debug("Got a successful probe for not yet established RR, we lost.");
- we_lost = true;
- } else {
- assert(i->probe_transaction->received);
- we_lost = memcmp(&i->probe_transaction->received->sender, &i->probe_transaction->received->destination, FAMILY_ADDRESS_SIZE(i->probe_transaction->received->family)) < 0;
- if (we_lost)
- log_debug("Got a successful probe reply for an established RR, and we have a lexicographically larger IP address and thus lost.");
- }
-
- if (we_lost) {
- dns_zone_item_conflict(i);
- return;
- }
-
- log_debug("Got a successful probe reply, but peer has lexicographically lower IP address and thus lost.");
- }
-
- dns_resource_record_to_string(i->rr, &pretty);
- log_debug("Record %s successfully probed.", strna(pretty));
-
- dns_zone_item_probe_stop(i);
- i->state = DNS_ZONE_ITEM_ESTABLISHED;
-}
-
-static int dns_zone_item_verify(DnsZoneItem *i) {
- _cleanup_free_ char *pretty = NULL;
- int r;
-
- assert(i);
-
- if (i->state != DNS_ZONE_ITEM_ESTABLISHED)
- return 0;
-
- dns_resource_record_to_string(i->rr, &pretty);
- log_debug("Verifying RR %s", strna(pretty));
-
- i->state = DNS_ZONE_ITEM_VERIFYING;
- r = dns_zone_item_probe_start(i);
- if (r < 0) {
- log_error_errno(r, "Failed to start probing for verifying RR: %m");
- i->state = DNS_ZONE_ITEM_ESTABLISHED;
- return r;
- }
-
- return 0;
-}
-
-int dns_zone_check_conflicts(DnsZone *zone, DnsResourceRecord *rr) {
- DnsZoneItem *i, *first;
- int c = 0;
-
- assert(zone);
- assert(rr);
-
- /* This checks whether a response RR we received from somebody
- * else is one that we actually thought was uniquely ours. If
- * so, we'll verify our RRs. */
-
- /* No conflict if we don't have the name at all. */
- first = hashmap_get(zone->by_name, DNS_RESOURCE_KEY_NAME(rr->key));
- if (!first)
- return 0;
-
- /* No conflict if we have the exact same RR */
- if (dns_zone_get(zone, rr))
- return 0;
-
- /* OK, somebody else has RRs for the same name. Yuck! Let's
- * start probing again */
-
- LIST_FOREACH(by_name, i, first) {
- if (dns_resource_record_equal(i->rr, rr))
- continue;
-
- dns_zone_item_verify(i);
- c++;
- }
-
- return c;
-}
-
-int dns_zone_verify_conflicts(DnsZone *zone, DnsResourceKey *key) {
- DnsZoneItem *i, *first;
- int c = 0;
-
- assert(zone);
-
- /* Somebody else notified us about a possible conflict. Let's
- * verify if that's true. */
-
- first = hashmap_get(zone->by_name, DNS_RESOURCE_KEY_NAME(key));
- if (!first)
- return 0;
-
- LIST_FOREACH(by_name, i, first) {
- dns_zone_item_verify(i);
- c++;
- }
-
- return c;
-}
-
-void dns_zone_verify_all(DnsZone *zone) {
- DnsZoneItem *i;
- Iterator iterator;
-
- assert(zone);
-
- HASHMAP_FOREACH(i, zone->by_key, iterator) {
- DnsZoneItem *j;
-
- LIST_FOREACH(by_key, j, i)
- dns_zone_item_verify(j);
- }
-}
~ianmdlvl / elogind.git / blobdiff