+++ /dev/null
-/*-*- 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 "resolved-dns-query.h"
-
-/* How long to wait for the query in total */
-#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
-
-#define CNAME_MAX 8
-#define QUERIES_MAX 2048
-
-static void dns_query_stop(DnsQuery *q) {
- DnsTransaction *t;
-
- assert(q);
-
- q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
-
- while ((t = set_steal_first(q->transactions))) {
- set_remove(t->queries, q);
- dns_transaction_gc(t);
- }
-}
-
-DnsQuery *dns_query_free(DnsQuery *q) {
- if (!q)
- return NULL;
-
- dns_query_stop(q);
- set_free(q->transactions);
-
- dns_question_unref(q->question);
- dns_answer_unref(q->answer);
-
- sd_bus_message_unref(q->request);
- sd_bus_track_unref(q->bus_track);
-
- if (q->manager) {
- LIST_REMOVE(queries, q->manager->dns_queries, q);
- q->manager->n_dns_queries--;
- }
-
- free(q);
-
- return NULL;
-}
-
-int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex, uint64_t flags) {
- _cleanup_(dns_query_freep) DnsQuery *q = NULL;
- unsigned i;
- int r;
-
- assert(m);
- assert(question);
-
- r = dns_question_is_valid(question);
- if (r < 0)
- return r;
-
- if (m->n_dns_queries >= QUERIES_MAX)
- return -EBUSY;
-
- q = new0(DnsQuery, 1);
- if (!q)
- return -ENOMEM;
-
- q->question = dns_question_ref(question);
- q->ifindex = ifindex;
- q->flags = flags;
-
- for (i = 0; i < question->n_keys; i++) {
- _cleanup_free_ char *p;
-
- r = dns_resource_key_to_string(question->keys[i], &p);
- if (r < 0)
- return r;
-
- log_debug("Looking up RR for %s", p);
- }
-
- LIST_PREPEND(queries, m->dns_queries, q);
- m->n_dns_queries++;
- q->manager = m;
-
- if (ret)
- *ret = q;
- q = NULL;
-
- return 0;
-}
-
-static void dns_query_complete(DnsQuery *q, DnsTransactionState state) {
- assert(q);
- assert(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
- assert(IN_SET(q->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
-
- /* Note that this call might invalidate the query. Callers
- * should hence not attempt to access the query or transaction
- * after calling this function. */
-
- q->state = state;
-
- dns_query_stop(q);
- if (q->complete)
- q->complete(q);
-}
-
-static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) {
- DnsQuery *q = userdata;
-
- assert(s);
- assert(q);
-
- dns_query_complete(q, DNS_TRANSACTION_TIMEOUT);
- return 0;
-}
-
-static int dns_query_add_transaction(DnsQuery *q, DnsScope *s, DnsResourceKey *key) {
- _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
- DnsTransaction *t;
- int r;
-
- assert(q);
- assert(s);
-
- r = set_ensure_allocated(&q->transactions, NULL);
- if (r < 0)
- return r;
-
- if (key) {
- question = dns_question_new(1);
- if (!question)
- return -ENOMEM;
-
- r = dns_question_add(question, key);
- if (r < 0)
- return r;
- } else
- question = dns_question_ref(q->question);
-
- t = dns_scope_find_transaction(s, question, true);
- if (!t) {
- r = dns_transaction_new(&t, s, question);
- if (r < 0)
- return r;
- }
-
- r = set_ensure_allocated(&t->queries, NULL);
- if (r < 0)
- goto gc;
-
- r = set_put(t->queries, q);
- if (r < 0)
- goto gc;
-
- r = set_put(q->transactions, t);
- if (r < 0) {
- set_remove(t->queries, q);
- goto gc;
- }
-
- return 0;
-
-gc:
- dns_transaction_gc(t);
- return r;
-}
-
-static int dns_query_add_transaction_split(DnsQuery *q, DnsScope *s) {
- int r;
-
- assert(q);
- assert(s);
-
- if (s->protocol == DNS_PROTOCOL_MDNS) {
- r = dns_query_add_transaction(q, s, NULL);
- if (r < 0)
- return r;
- } else {
- unsigned i;
-
- /* On DNS and LLMNR we can only send a single
- * question per datagram, hence issue multiple
- * transactions. */
-
- for (i = 0; i < q->question->n_keys; i++) {
- r = dns_query_add_transaction(q, s, q->question->keys[i]);
- if (r < 0)
- return r;
- }
- }
-
- return 0;
-}
-
-int dns_query_go(DnsQuery *q) {
- DnsScopeMatch found = DNS_SCOPE_NO;
- DnsScope *s, *first = NULL;
- DnsTransaction *t;
- const char *name;
- Iterator i;
- int r;
-
- assert(q);
-
- if (q->state != DNS_TRANSACTION_NULL)
- return 0;
-
- assert(q->question);
- assert(q->question->n_keys > 0);
-
- name = DNS_RESOURCE_KEY_NAME(q->question->keys[0]);
-
- LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
- DnsScopeMatch match;
-
- match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
- if (match < 0)
- return match;
-
- if (match == DNS_SCOPE_NO)
- continue;
-
- found = match;
-
- if (match == DNS_SCOPE_YES) {
- first = s;
- break;
- } else {
- assert(match == DNS_SCOPE_MAYBE);
-
- if (!first)
- first = s;
- }
- }
-
- if (found == DNS_SCOPE_NO)
- return -ESRCH;
-
- r = dns_query_add_transaction_split(q, first);
- if (r < 0)
- goto fail;
-
- LIST_FOREACH(scopes, s, first->scopes_next) {
- DnsScopeMatch match;
-
- match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
- if (match < 0)
- goto fail;
-
- if (match != found)
- continue;
-
- r = dns_query_add_transaction_split(q, s);
- if (r < 0)
- goto fail;
- }
-
- q->answer = dns_answer_unref(q->answer);
- q->answer_ifindex = 0;
- q->answer_rcode = 0;
- q->answer_family = AF_UNSPEC;
- q->answer_protocol = _DNS_PROTOCOL_INVALID;
-
- r = sd_event_add_time(
- q->manager->event,
- &q->timeout_event_source,
- clock_boottime_or_monotonic(),
- now(clock_boottime_or_monotonic()) + QUERY_TIMEOUT_USEC, 0,
- on_query_timeout, q);
- if (r < 0)
- goto fail;
-
- q->state = DNS_TRANSACTION_PENDING;
- q->block_ready++;
-
- /* Start the transactions that are not started yet */
- SET_FOREACH(t, q->transactions, i) {
- if (t->state != DNS_TRANSACTION_NULL)
- continue;
-
- r = dns_transaction_go(t);
- if (r < 0)
- goto fail;
- }
-
- q->block_ready--;
- dns_query_ready(q);
-
- return 1;
-
-fail:
- dns_query_stop(q);
- return r;
-}
-
-void dns_query_ready(DnsQuery *q) {
- DnsTransaction *t;
- DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- int rcode = 0;
- DnsScope *scope = NULL;
- bool pending = false;
- Iterator i;
-
- assert(q);
- assert(IN_SET(q->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
-
- /* Note that this call might invalidate the query. Callers
- * should hence not attempt to access the query or transaction
- * after calling this function, unless the block_ready
- * counter was explicitly bumped before doing so. */
-
- if (q->block_ready > 0)
- return;
-
- SET_FOREACH(t, q->transactions, i) {
-
- /* If we found a successful answer, ignore all answers from other scopes */
- if (state == DNS_TRANSACTION_SUCCESS && t->scope != scope)
- continue;
-
- /* One of the transactions is still going on, let's maybe wait for it */
- if (IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_NULL)) {
- pending = true;
- continue;
- }
-
- /* One of the transactions is successful, let's use
- * it, and copy its data out */
- if (t->state == DNS_TRANSACTION_SUCCESS) {
- DnsAnswer *a;
-
- if (t->received) {
- rcode = DNS_PACKET_RCODE(t->received);
- a = t->received->answer;
- } else {
- rcode = t->cached_rcode;
- a = t->cached;
- }
-
- if (state == DNS_TRANSACTION_SUCCESS) {
- DnsAnswer *merged;
-
- merged = dns_answer_merge(answer, a);
- if (!merged) {
- dns_query_complete(q, DNS_TRANSACTION_RESOURCES);
- return;
- }
-
- dns_answer_unref(answer);
- answer = merged;
- } else {
- dns_answer_unref(answer);
- answer = dns_answer_ref(a);
- }
-
- scope = t->scope;
- state = DNS_TRANSACTION_SUCCESS;
- continue;
- }
-
- /* One of the transactions has failed, let's see
- * whether we find anything better, but if not, return
- * its response data */
- if (state != DNS_TRANSACTION_SUCCESS && t->state == DNS_TRANSACTION_FAILURE) {
- DnsAnswer *a;
-
- if (t->received) {
- rcode = DNS_PACKET_RCODE(t->received);
- a = t->received->answer;
- } else {
- rcode = t->cached_rcode;
- a = t->cached;
- }
-
- dns_answer_unref(answer);
- answer = dns_answer_ref(a);
-
- scope = t->scope;
- state = DNS_TRANSACTION_FAILURE;
- continue;
- }
-
- if (state == DNS_TRANSACTION_NO_SERVERS && t->state != DNS_TRANSACTION_NO_SERVERS)
- state = t->state;
- }
-
- if (pending) {
-
- /* If so far we weren't successful, and there's
- * something still pending, then wait for it */
- if (state != DNS_TRANSACTION_SUCCESS)
- return;
-
- /* If we already were successful, then only wait for
- * other transactions on the same scope to finish. */
- SET_FOREACH(t, q->transactions, i) {
- if (t->scope == scope && IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_NULL))
- return;
- }
- }
-
- if (IN_SET(state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE)) {
- q->answer = dns_answer_ref(answer);
- q->answer_rcode = rcode;
- q->answer_ifindex = (scope && scope->link) ? scope->link->ifindex : 0;
- q->answer_protocol = scope ? scope->protocol : _DNS_PROTOCOL_INVALID;
- q->answer_family = scope ? scope->family : AF_UNSPEC;
- }
-
- dns_query_complete(q, state);
-}
-
-int dns_query_cname_redirect(DnsQuery *q, const char *name) {
- _cleanup_(dns_question_unrefp) DnsQuestion *nq = NULL;
- int r;
-
- assert(q);
-
- if (q->n_cname_redirects > CNAME_MAX)
- return -ELOOP;
-
- r = dns_question_cname_redirect(q->question, name, &nq);
- if (r < 0)
- return r;
-
- dns_question_unref(q->question);
- q->question = nq;
- nq = NULL;
-
- q->n_cname_redirects++;
-
- dns_query_stop(q);
- q->state = DNS_TRANSACTION_NULL;
-
- return 0;
-}
-
-static int on_bus_track(sd_bus_track *t, void *userdata) {
- DnsQuery *q = userdata;
-
- assert(t);
- assert(q);
-
- log_debug("Client of active query vanished, aborting query.");
- dns_query_complete(q, DNS_TRANSACTION_ABORTED);
- return 0;
-}
-
-int dns_query_bus_track(DnsQuery *q, sd_bus *bus, sd_bus_message *m) {
- int r;
-
- assert(q);
- assert(m);
-
- if (!q->bus_track) {
- r = sd_bus_track_new(bus, &q->bus_track, on_bus_track, q);
- if (r < 0)
- return r;
- }
-
- r = sd_bus_track_add_sender(q->bus_track, m);
- if (r < 0)
- return r;
-
- return 0;
-}
~ianmdlvl / elogind.git / blobdiff