diff options
Diffstat (limited to 'src/resolve/resolved-dns-query.c')
| -rw-r--r-- | src/resolve/resolved-dns-query.c | 1117 |
1 files changed, 0 insertions, 1117 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c deleted file mode 100644 index e03db4d003..0000000000 --- a/src/resolve/resolved-dns-query.c +++ /dev/null @@ -1,1117 +0,0 @@ -/*** - 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 "alloc-util.h" -#include "dns-domain.h" -#include "dns-type.h" -#include "hostname-util.h" -#include "local-addresses.h" -#include "resolved-dns-query.h" -#include "resolved-dns-synthesize.h" -#include "resolved-etc-hosts.h" -#include "string-util.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 -#define AUXILIARY_QUERIES_MAX 64 - -static int dns_query_candidate_new(DnsQueryCandidate **ret, DnsQuery *q, DnsScope *s) { - DnsQueryCandidate *c; - - assert(ret); - assert(q); - assert(s); - - c = new0(DnsQueryCandidate, 1); - if (!c) - return -ENOMEM; - - c->query = q; - c->scope = s; - - LIST_PREPEND(candidates_by_query, q->candidates, c); - LIST_PREPEND(candidates_by_scope, s->query_candidates, c); - - *ret = c; - return 0; -} - -static void dns_query_candidate_stop(DnsQueryCandidate *c) { - DnsTransaction *t; - - assert(c); - - while ((t = set_steal_first(c->transactions))) { - set_remove(t->notify_query_candidates, c); - set_remove(t->notify_query_candidates_done, c); - dns_transaction_gc(t); - } -} - -DnsQueryCandidate* dns_query_candidate_free(DnsQueryCandidate *c) { - - if (!c) - return NULL; - - dns_query_candidate_stop(c); - - set_free(c->transactions); - dns_search_domain_unref(c->search_domain); - - if (c->query) - LIST_REMOVE(candidates_by_query, c->query->candidates, c); - - if (c->scope) - LIST_REMOVE(candidates_by_scope, c->scope->query_candidates, c); - - return mfree(c); -} - -static int dns_query_candidate_next_search_domain(DnsQueryCandidate *c) { - DnsSearchDomain *next = NULL; - - assert(c); - - if (c->search_domain && c->search_domain->linked) - next = c->search_domain->domains_next; - else - next = dns_scope_get_search_domains(c->scope); - - for (;;) { - if (!next) /* We hit the end of the list */ - return 0; - - if (!next->route_only) - break; - - /* Skip over route-only domains */ - next = next->domains_next; - } - - dns_search_domain_unref(c->search_domain); - c->search_domain = dns_search_domain_ref(next); - - return 1; -} - -static int dns_query_candidate_add_transaction(DnsQueryCandidate *c, DnsResourceKey *key) { - DnsTransaction *t; - int r; - - assert(c); - assert(key); - - t = dns_scope_find_transaction(c->scope, key, true); - if (!t) { - r = dns_transaction_new(&t, c->scope, key); - if (r < 0) - return r; - } else { - if (set_contains(c->transactions, t)) - return 0; - } - - r = set_ensure_allocated(&c->transactions, NULL); - if (r < 0) - goto gc; - - r = set_ensure_allocated(&t->notify_query_candidates, NULL); - if (r < 0) - goto gc; - - r = set_ensure_allocated(&t->notify_query_candidates_done, NULL); - if (r < 0) - goto gc; - - r = set_put(t->notify_query_candidates, c); - if (r < 0) - goto gc; - - r = set_put(c->transactions, t); - if (r < 0) { - (void) set_remove(t->notify_query_candidates, c); - goto gc; - } - - t->clamp_ttl = c->query->clamp_ttl; - return 1; - -gc: - dns_transaction_gc(t); - return r; -} - -static int dns_query_candidate_go(DnsQueryCandidate *c) { - DnsTransaction *t; - Iterator i; - int r; - unsigned n = 0; - - assert(c); - - /* Start the transactions that are not started yet */ - SET_FOREACH(t, c->transactions, i) { - if (t->state != DNS_TRANSACTION_NULL) - continue; - - r = dns_transaction_go(t); - if (r < 0) - return r; - - n++; - } - - /* If there was nothing to start, then let's proceed immediately */ - if (n == 0) - dns_query_candidate_notify(c); - - return 0; -} - -static DnsTransactionState dns_query_candidate_state(DnsQueryCandidate *c) { - DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; - DnsTransaction *t; - Iterator i; - - assert(c); - - if (c->error_code != 0) - return DNS_TRANSACTION_ERRNO; - - SET_FOREACH(t, c->transactions, i) { - - switch (t->state) { - - case DNS_TRANSACTION_NULL: - /* If there's a NULL transaction pending, then - * this means not all transactions where - * started yet, and we were called from within - * the stackframe that is supposed to start - * remaining transactions. In this case, - * simply claim the candidate is pending. */ - - case DNS_TRANSACTION_PENDING: - case DNS_TRANSACTION_VALIDATING: - /* If there's one transaction currently in - * VALIDATING state, then this means there's - * also one in PENDING state, hence we can - * return PENDING immediately. */ - return DNS_TRANSACTION_PENDING; - - case DNS_TRANSACTION_SUCCESS: - state = t->state; - break; - - default: - if (state != DNS_TRANSACTION_SUCCESS) - state = t->state; - - break; - } - } - - return state; -} - -static bool dns_query_candidate_is_routable(DnsQueryCandidate *c, uint16_t type) { - int family; - - assert(c); - - /* Checks whether the specified RR type matches an address family that is routable on the link(s) the scope of - * this candidate belongs to. Specifically, whether there's a routable IPv4 address on it if we query an A RR, - * or a routable IPv6 address if we query an AAAA RR. */ - - if (!c->query->suppress_unroutable_family) - return true; - - if (c->scope->protocol != DNS_PROTOCOL_DNS) - return true; - - family = dns_type_to_af(type); - if (family < 0) - return true; - - if (c->scope->link) - return link_relevant(c->scope->link, family, false); - else - return manager_routable(c->scope->manager, family); -} - -static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) { - DnsQuestion *question; - DnsResourceKey *key; - int n = 0, r; - - assert(c); - - dns_query_candidate_stop(c); - - question = dns_query_question_for_protocol(c->query, c->scope->protocol); - - /* Create one transaction per question key */ - DNS_QUESTION_FOREACH(key, question) { - _cleanup_(dns_resource_key_unrefp) DnsResourceKey *new_key = NULL; - DnsResourceKey *qkey; - - if (!dns_query_candidate_is_routable(c, key->type)) - continue; - - if (c->search_domain) { - r = dns_resource_key_new_append_suffix(&new_key, key, c->search_domain->name); - if (r < 0) - goto fail; - - qkey = new_key; - } else - qkey = key; - - if (!dns_scope_good_key(c->scope, qkey)) - continue; - - r = dns_query_candidate_add_transaction(c, qkey); - if (r < 0) - goto fail; - - n++; - } - - return n; - -fail: - dns_query_candidate_stop(c); - return r; -} - -void dns_query_candidate_notify(DnsQueryCandidate *c) { - DnsTransactionState state; - int r; - - assert(c); - - state = dns_query_candidate_state(c); - - if (DNS_TRANSACTION_IS_LIVE(state)) - return; - - if (state != DNS_TRANSACTION_SUCCESS && c->search_domain) { - - r = dns_query_candidate_next_search_domain(c); - if (r < 0) - goto fail; - - if (r > 0) { - /* OK, there's another search domain to try, let's do so. */ - - r = dns_query_candidate_setup_transactions(c); - if (r < 0) - goto fail; - - if (r > 0) { - /* New transactions where queued. Start them and wait */ - - r = dns_query_candidate_go(c); - if (r < 0) - goto fail; - - return; - } - } - - } - - dns_query_ready(c->query); - return; - -fail: - log_warning_errno(r, "Failed to follow search domains: %m"); - c->error_code = r; - dns_query_ready(c->query); -} - -static void dns_query_stop(DnsQuery *q) { - DnsQueryCandidate *c; - - assert(q); - - q->timeout_event_source = sd_event_source_unref(q->timeout_event_source); - - LIST_FOREACH(candidates_by_query, c, q->candidates) - dns_query_candidate_stop(c); -} - -static void dns_query_free_candidates(DnsQuery *q) { - assert(q); - - while (q->candidates) - dns_query_candidate_free(q->candidates); -} - -static void dns_query_reset_answer(DnsQuery *q) { - assert(q); - - q->answer = dns_answer_unref(q->answer); - q->answer_rcode = 0; - q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; - q->answer_errno = 0; - q->answer_authenticated = false; - q->answer_protocol = _DNS_PROTOCOL_INVALID; - q->answer_family = AF_UNSPEC; - q->answer_search_domain = dns_search_domain_unref(q->answer_search_domain); -} - -DnsQuery *dns_query_free(DnsQuery *q) { - if (!q) - return NULL; - - while (q->auxiliary_queries) - dns_query_free(q->auxiliary_queries); - - if (q->auxiliary_for) { - assert(q->auxiliary_for->n_auxiliary_queries > 0); - q->auxiliary_for->n_auxiliary_queries--; - LIST_REMOVE(auxiliary_queries, q->auxiliary_for->auxiliary_queries, q); - } - - dns_query_free_candidates(q); - - dns_question_unref(q->question_idna); - dns_question_unref(q->question_utf8); - - dns_query_reset_answer(q); - - sd_bus_message_unref(q->request); - sd_bus_track_unref(q->bus_track); - - dns_packet_unref(q->request_dns_packet); - - if (q->request_dns_stream) { - /* Detach the stream from our query, in case something else keeps a reference to it. */ - q->request_dns_stream->complete = NULL; - q->request_dns_stream->on_packet = NULL; - q->request_dns_stream->query = NULL; - dns_stream_unref(q->request_dns_stream); - } - - free(q->request_address_string); - - if (q->manager) { - LIST_REMOVE(queries, q->manager->dns_queries, q); - q->manager->n_dns_queries--; - } - - return mfree(q); -} - -int dns_query_new( - Manager *m, - DnsQuery **ret, - DnsQuestion *question_utf8, - DnsQuestion *question_idna, - int ifindex, - uint64_t flags) { - - _cleanup_(dns_query_freep) DnsQuery *q = NULL; - DnsResourceKey *key; - bool good = false; - int r; - char key_str[DNS_RESOURCE_KEY_STRING_MAX]; - - assert(m); - - if (dns_question_size(question_utf8) > 0) { - r = dns_question_is_valid_for_query(question_utf8); - if (r < 0) - return r; - if (r == 0) - return -EINVAL; - - good = true; - } - - /* If the IDNA and UTF8 questions are the same, merge their references */ - r = dns_question_is_equal(question_idna, question_utf8); - if (r < 0) - return r; - if (r > 0) - question_idna = question_utf8; - else { - if (dns_question_size(question_idna) > 0) { - r = dns_question_is_valid_for_query(question_idna); - if (r < 0) - return r; - if (r == 0) - return -EINVAL; - - good = true; - } - } - - if (!good) /* don't allow empty queries */ - return -EINVAL; - - if (m->n_dns_queries >= QUERIES_MAX) - return -EBUSY; - - q = new0(DnsQuery, 1); - if (!q) - return -ENOMEM; - - q->question_utf8 = dns_question_ref(question_utf8); - q->question_idna = dns_question_ref(question_idna); - q->ifindex = ifindex; - q->flags = flags; - q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; - q->answer_protocol = _DNS_PROTOCOL_INVALID; - q->answer_family = AF_UNSPEC; - - /* First dump UTF8 question */ - DNS_QUESTION_FOREACH(key, question_utf8) - log_debug("Looking up RR for %s.", - dns_resource_key_to_string(key, key_str, sizeof key_str)); - - /* And then dump the IDNA question, but only what hasn't been dumped already through the UTF8 question. */ - DNS_QUESTION_FOREACH(key, question_idna) { - r = dns_question_contains(question_utf8, key); - if (r < 0) - return r; - if (r > 0) - continue; - - log_debug("Looking up IDNA RR for %s.", - dns_resource_key_to_string(key, key_str, sizeof key_str)); - } - - LIST_PREPEND(queries, m->dns_queries, q); - m->n_dns_queries++; - q->manager = m; - - if (ret) - *ret = q; - q = NULL; - - return 0; -} - -int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for) { - assert(q); - assert(auxiliary_for); - - /* Ensure that the query is not auxiliary yet, and - * nothing else is auxiliary to it either */ - assert(!q->auxiliary_for); - assert(!q->auxiliary_queries); - - /* Ensure that the unit we shall be made auxiliary for isn't - * auxiliary itself */ - assert(!auxiliary_for->auxiliary_for); - - if (auxiliary_for->n_auxiliary_queries >= AUXILIARY_QUERIES_MAX) - return -EAGAIN; - - LIST_PREPEND(auxiliary_queries, auxiliary_for->auxiliary_queries, q); - q->auxiliary_for = auxiliary_for; - - auxiliary_for->n_auxiliary_queries++; - return 0; -} - -static void dns_query_complete(DnsQuery *q, DnsTransactionState state) { - assert(q); - assert(!DNS_TRANSACTION_IS_LIVE(state)); - assert(DNS_TRANSACTION_IS_LIVE(q->state)); - - /* 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_candidate(DnsQuery *q, DnsScope *s) { - DnsQueryCandidate *c; - int r; - - assert(q); - assert(s); - - r = dns_query_candidate_new(&c, q, s); - if (r < 0) - return r; - - /* If this a single-label domain on DNS, we might append a suitable search domain first. */ - if ((q->flags & SD_RESOLVED_NO_SEARCH) == 0) { - r = dns_scope_name_needs_search_domain(s, dns_question_first_name(q->question_idna)); - if (r < 0) - goto fail; - if (r > 0) { - /* OK, we need a search domain now. Let's find one for this scope */ - - r = dns_query_candidate_next_search_domain(c); - if (r <= 0) /* if there's no search domain, then we won't add any transaction. */ - goto fail; - } - } - - r = dns_query_candidate_setup_transactions(c); - if (r < 0) - goto fail; - - return 0; - -fail: - dns_query_candidate_free(c); - return r; -} - -static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) { - _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; - int r; - - assert(q); - assert(state); - - /* Tries to synthesize localhost RR replies (and others) where appropriate. Note that this is done *after* the - * the normal lookup finished. The data from the network hence takes precedence over the data we - * synthesize. (But note that many scopes refuse to resolve certain domain names) */ - - if (!IN_SET(*state, - DNS_TRANSACTION_RCODE_FAILURE, - DNS_TRANSACTION_NO_SERVERS, - DNS_TRANSACTION_TIMEOUT, - DNS_TRANSACTION_ATTEMPTS_MAX_REACHED, - DNS_TRANSACTION_NETWORK_DOWN, - DNS_TRANSACTION_NOT_FOUND)) - return 0; - - r = dns_synthesize_answer( - q->manager, - q->question_utf8, - q->ifindex, - &answer); - - if (r <= 0) - return r; - - dns_query_reset_answer(q); - - q->answer = answer; - answer = NULL; - q->answer_rcode = DNS_RCODE_SUCCESS; - q->answer_protocol = dns_synthesize_protocol(q->flags); - q->answer_family = dns_synthesize_family(q->flags); - q->answer_authenticated = true; - - *state = DNS_TRANSACTION_SUCCESS; - - return 1; -} - -static int dns_query_try_etc_hosts(DnsQuery *q) { - _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; - int r; - - assert(q); - - /* Looks in /etc/hosts for matching entries. Note that this is done *before* the normal lookup is done. The - * data from /etc/hosts hence takes precedence over the network. */ - - r = manager_etc_hosts_lookup( - q->manager, - q->question_utf8, - &answer); - if (r <= 0) - return r; - - dns_query_reset_answer(q); - - q->answer = answer; - answer = NULL; - q->answer_rcode = DNS_RCODE_SUCCESS; - q->answer_protocol = dns_synthesize_protocol(q->flags); - q->answer_family = dns_synthesize_family(q->flags); - q->answer_authenticated = true; - - return 1; -} - -int dns_query_go(DnsQuery *q) { - DnsScopeMatch found = DNS_SCOPE_NO; - DnsScope *s, *first = NULL; - DnsQueryCandidate *c; - int r; - - assert(q); - - if (q->state != DNS_TRANSACTION_NULL) - return 0; - - r = dns_query_try_etc_hosts(q); - if (r < 0) - return r; - if (r > 0) { - dns_query_complete(q, DNS_TRANSACTION_SUCCESS); - return 1; - } - - LIST_FOREACH(scopes, s, q->manager->dns_scopes) { - DnsScopeMatch match; - const char *name; - - name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol)); - if (!name) - continue; - - 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) { - DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; - - r = dns_query_synthesize_reply(q, &state); - if (r < 0) - return r; - - dns_query_complete(q, state); - return 1; - } - - r = dns_query_add_candidate(q, first); - if (r < 0) - goto fail; - - LIST_FOREACH(scopes, s, first->scopes_next) { - DnsScopeMatch match; - const char *name; - - name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol)); - if (!name) - continue; - - match = dns_scope_good_domain(s, q->ifindex, q->flags, name); - if (match < 0) - goto fail; - - if (match != found) - continue; - - r = dns_query_add_candidate(q, s); - if (r < 0) - goto fail; - } - - dns_query_reset_answer(q); - - 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; - - (void) sd_event_source_set_description(q->timeout_event_source, "query-timeout"); - - q->state = DNS_TRANSACTION_PENDING; - q->block_ready++; - - /* Start the transactions */ - LIST_FOREACH(candidates_by_query, c, q->candidates) { - r = dns_query_candidate_go(c); - if (r < 0) { - q->block_ready--; - goto fail; - } - } - - q->block_ready--; - dns_query_ready(q); - - return 1; - -fail: - dns_query_stop(q); - return r; -} - -static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) { - DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; - bool has_authenticated = false, has_non_authenticated = false; - DnssecResult dnssec_result_authenticated = _DNSSEC_RESULT_INVALID, dnssec_result_non_authenticated = _DNSSEC_RESULT_INVALID; - DnsTransaction *t; - Iterator i; - int r; - - assert(q); - - if (!c) { - r = dns_query_synthesize_reply(q, &state); - if (r < 0) - goto fail; - - dns_query_complete(q, state); - return; - } - - if (c->error_code != 0) { - /* If the candidate had an error condition of its own, start with that. */ - state = DNS_TRANSACTION_ERRNO; - q->answer = dns_answer_unref(q->answer); - q->answer_rcode = 0; - q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; - q->answer_errno = c->error_code; - } - - SET_FOREACH(t, c->transactions, i) { - - switch (t->state) { - - case DNS_TRANSACTION_SUCCESS: { - /* We found a successfully reply, merge it into the answer */ - r = dns_answer_extend(&q->answer, t->answer); - if (r < 0) - goto fail; - - q->answer_rcode = t->answer_rcode; - q->answer_errno = 0; - - if (t->answer_authenticated) { - has_authenticated = true; - dnssec_result_authenticated = t->answer_dnssec_result; - } else { - has_non_authenticated = true; - dnssec_result_non_authenticated = t->answer_dnssec_result; - } - - state = DNS_TRANSACTION_SUCCESS; - break; - } - - case DNS_TRANSACTION_NULL: - case DNS_TRANSACTION_PENDING: - case DNS_TRANSACTION_VALIDATING: - case DNS_TRANSACTION_ABORTED: - /* Ignore transactions that didn't complete */ - continue; - - default: - /* Any kind of failure? Store the data away, - * if there's nothing stored yet. */ - - if (state == DNS_TRANSACTION_SUCCESS) - continue; - - q->answer = dns_answer_unref(q->answer); - q->answer_rcode = t->answer_rcode; - q->answer_dnssec_result = t->answer_dnssec_result; - q->answer_errno = t->answer_errno; - - state = t->state; - break; - } - } - - if (state == DNS_TRANSACTION_SUCCESS) { - q->answer_authenticated = has_authenticated && !has_non_authenticated; - q->answer_dnssec_result = q->answer_authenticated ? dnssec_result_authenticated : dnssec_result_non_authenticated; - } - - q->answer_protocol = c->scope->protocol; - q->answer_family = c->scope->family; - - dns_search_domain_unref(q->answer_search_domain); - q->answer_search_domain = dns_search_domain_ref(c->search_domain); - - r = dns_query_synthesize_reply(q, &state); - if (r < 0) - goto fail; - - dns_query_complete(q, state); - return; - -fail: - q->answer_errno = -r; - dns_query_complete(q, DNS_TRANSACTION_ERRNO); -} - -void dns_query_ready(DnsQuery *q) { - - DnsQueryCandidate *bad = NULL, *c; - bool pending = false; - - assert(q); - assert(DNS_TRANSACTION_IS_LIVE(q->state)); - - /* 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; - - LIST_FOREACH(candidates_by_query, c, q->candidates) { - DnsTransactionState state; - - state = dns_query_candidate_state(c); - switch (state) { - - case DNS_TRANSACTION_SUCCESS: - /* One of the candidates is successful, - * let's use it, and copy its data out */ - dns_query_accept(q, c); - return; - - case DNS_TRANSACTION_NULL: - case DNS_TRANSACTION_PENDING: - case DNS_TRANSACTION_VALIDATING: - /* One of the candidates is still going on, - * let's maybe wait for it */ - pending = true; - break; - - default: - /* Any kind of failure */ - bad = c; - break; - } - } - - if (pending) - return; - - dns_query_accept(q, bad); -} - -static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) { - _cleanup_(dns_question_unrefp) DnsQuestion *nq_idna = NULL, *nq_utf8 = NULL; - int r, k; - - assert(q); - - q->n_cname_redirects++; - if (q->n_cname_redirects > CNAME_MAX) - return -ELOOP; - - r = dns_question_cname_redirect(q->question_idna, cname, &nq_idna); - if (r < 0) - return r; - else if (r > 0) - log_debug("Following CNAME/DNAME %s → %s.", dns_question_first_name(q->question_idna), dns_question_first_name(nq_idna)); - - k = dns_question_is_equal(q->question_idna, q->question_utf8); - if (k < 0) - return r; - if (k > 0) { - /* Same question? Shortcut new question generation */ - nq_utf8 = dns_question_ref(nq_idna); - k = r; - } else { - k = dns_question_cname_redirect(q->question_utf8, cname, &nq_utf8); - if (k < 0) - return k; - else if (k > 0) - log_debug("Following UTF8 CNAME/DNAME %s → %s.", dns_question_first_name(q->question_utf8), dns_question_first_name(nq_utf8)); - } - - if (r == 0 && k == 0) /* No actual cname happened? */ - return -ELOOP; - - if (q->answer_protocol == DNS_PROTOCOL_DNS) { - /* Don't permit CNAME redirects from unicast DNS to LLMNR or MulticastDNS, so that global resources - * cannot invade the local namespace. The opposite way we permit: local names may redirect to global - * ones. */ - - q->flags &= ~(SD_RESOLVED_LLMNR|SD_RESOLVED_MDNS); /* mask away the local protocols */ - } - - /* Turn off searching for the new name */ - q->flags |= SD_RESOLVED_NO_SEARCH; - - dns_question_unref(q->question_idna); - q->question_idna = nq_idna; - nq_idna = NULL; - - dns_question_unref(q->question_utf8); - q->question_utf8 = nq_utf8; - nq_utf8 = NULL; - - dns_query_free_candidates(q); - dns_query_reset_answer(q); - - q->state = DNS_TRANSACTION_NULL; - - return 0; -} - -int dns_query_process_cname(DnsQuery *q) { - _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL; - DnsQuestion *question; - DnsResourceRecord *rr; - int r; - - assert(q); - - if (!IN_SET(q->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_NULL)) - return DNS_QUERY_NOMATCH; - - question = dns_query_question_for_protocol(q, q->answer_protocol); - - DNS_ANSWER_FOREACH(rr, q->answer) { - r = dns_question_matches_rr(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain)); - if (r < 0) - return r; - if (r > 0) - return DNS_QUERY_MATCH; /* The answer matches directly, no need to follow cnames */ - - r = dns_question_matches_cname_or_dname(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain)); - if (r < 0) - return r; - if (r > 0 && !cname) - cname = dns_resource_record_ref(rr); - } - - if (!cname) - return DNS_QUERY_NOMATCH; /* No match and no cname to follow */ - - if (q->flags & SD_RESOLVED_NO_CNAME) - return -ELOOP; - - /* OK, let's actually follow the CNAME */ - r = dns_query_cname_redirect(q, cname); - if (r < 0) - return r; - - /* Let's see if the answer can already answer the new - * redirected question */ - r = dns_query_process_cname(q); - if (r != DNS_QUERY_NOMATCH) - return r; - - /* OK, it cannot, let's begin with the new query */ - r = dns_query_go(q); - if (r < 0) - return r; - - return DNS_QUERY_RESTARTED; /* We restarted the query for a new cname */ -} - -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_message *m) { - int r; - - assert(q); - assert(m); - - if (!q->bus_track) { - r = sd_bus_track_new(sd_bus_message_get_bus(m), &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; -} - -DnsQuestion* dns_query_question_for_protocol(DnsQuery *q, DnsProtocol protocol) { - assert(q); - - switch (protocol) { - - case DNS_PROTOCOL_DNS: - return q->question_idna; - - case DNS_PROTOCOL_MDNS: - case DNS_PROTOCOL_LLMNR: - return q->question_utf8; - - default: - return NULL; - } -} - -const char *dns_query_string(DnsQuery *q) { - const char *name; - int r; - - /* Returns a somewhat useful human-readable lookup key string for this query */ - - if (q->request_address_string) - return q->request_address_string; - - if (q->request_address_valid) { - r = in_addr_to_string(q->request_family, &q->request_address, &q->request_address_string); - if (r >= 0) - return q->request_address_string; - } - - name = dns_question_first_name(q->question_utf8); - if (name) - return name; - - return dns_question_first_name(q->question_idna); -} |