X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fresolve%2Fresolved-dns-query.c;h=36cfc026eaf7a67641b25f82c89448f7bbedd7d0;hp=a56e295f4fd274d5978e62b70d95c60c08ed62ef;hb=8db0d2f5c37e7e8f5bfce016cfdad7947a3ea939;hpb=7e8e0422aeb16f2a09a40546c61df753d10029b6 diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c index a56e295f4..36cfc026e 100644 --- a/src/resolve/resolved-dns-query.c +++ b/src/resolve/resolved-dns-query.c @@ -19,473 +19,41 @@ along with systemd; If not, see . ***/ +#include "af-list.h" + #include "resolved-dns-query.h" #include "resolved-dns-domain.h" -#define TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC) +/* How long to wait for the query in total */ #define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC) -#define ATTEMPTS_MAX 8 + #define CNAME_MAX 8 #define QUERIES_MAX 2048 -static int dns_query_transaction_go(DnsQueryTransaction *t); - -DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) { - DnsQuery *q; - - if (!t) - return NULL; - - sd_event_source_unref(t->timeout_event_source); - - dns_question_unref(t->question); - dns_packet_unref(t->sent); - dns_packet_unref(t->received); - dns_answer_unref(t->cached); - - sd_event_source_unref(t->tcp_event_source); - safe_close(t->tcp_fd); - - if (t->scope) { - LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); - - if (t->id != 0) - hashmap_remove(t->scope->manager->dns_query_transactions, UINT_TO_PTR(t->id)); - } - - while ((q = set_steal_first(t->queries))) - set_remove(q->transactions, t); - - set_free(t->queries); - - free(t); - return NULL; -} - -DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQueryTransaction*, dns_query_transaction_free); - -static void dns_query_transaction_gc(DnsQueryTransaction *t) { - assert(t); - - if (t->block_gc > 0) - return; - - if (set_isempty(t->queries)) - dns_query_transaction_free(t); -} - -static int dns_query_transaction_new(DnsQueryTransaction **ret, DnsScope *s, DnsQuestion *q) { - _cleanup_(dns_query_transaction_freep) DnsQueryTransaction *t = NULL; - int r; +static void dns_query_stop(DnsQuery *q) { + DnsTransaction *t; - assert(ret); - assert(s); assert(q); - r = hashmap_ensure_allocated(&s->manager->dns_query_transactions, NULL, NULL); - if (r < 0) - return r; - - t = new0(DnsQueryTransaction, 1); - if (!t) - return -ENOMEM; - - t->tcp_fd = -1; - t->question = dns_question_ref(q); - - do - random_bytes(&t->id, sizeof(t->id)); - while (t->id == 0 || - hashmap_get(s->manager->dns_query_transactions, UINT_TO_PTR(t->id))); - - r = hashmap_put(s->manager->dns_query_transactions, UINT_TO_PTR(t->id), t); - if (r < 0) { - t->id = 0; - return r; - } - - LIST_PREPEND(transactions_by_scope, s->transactions, t); - t->scope = s; - - if (ret) - *ret = t; - - t = NULL; - - return 0; -} - -static void dns_query_transaction_stop(DnsQueryTransaction *t) { - assert(t); - - t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); - t->tcp_event_source = sd_event_source_unref(t->tcp_event_source); - t->tcp_fd = safe_close(t->tcp_fd); -} - -void dns_query_transaction_complete(DnsQueryTransaction *t, DnsQueryState state) { - DnsQuery *q; - Iterator i; - - assert(t); - assert(!IN_SET(state, DNS_QUERY_NULL, DNS_QUERY_PENDING)); - assert(IN_SET(t->state, DNS_QUERY_NULL, DNS_QUERY_PENDING)); - - /* Note that this call might invalidate the query. Callers - * should hence not attempt to access the query or transaction - * after calling this function. */ - - t->state = state; - - dns_query_transaction_stop(t); - - /* Notify all queries that are interested, but make sure the - * transaction isn't freed while we are still looking at it */ - t->block_gc++; - SET_FOREACH(q, t->queries, i) - dns_query_ready(q); - t->block_gc--; - - dns_query_transaction_gc(t); -} - -static int on_tcp_ready(sd_event_source *s, int fd, uint32_t revents, void *userdata) { - DnsQueryTransaction *t = userdata; - int r; - - assert(t); - - if (revents & EPOLLOUT) { - struct iovec iov[2]; - be16_t sz; - ssize_t ss; - - sz = htobe16(t->sent->size); - - iov[0].iov_base = &sz; - iov[0].iov_len = sizeof(sz); - iov[1].iov_base = DNS_PACKET_DATA(t->sent); - iov[1].iov_len = t->sent->size; - - IOVEC_INCREMENT(iov, 2, t->tcp_written); - - ss = writev(fd, iov, 2); - if (ss < 0) { - if (errno != EINTR && errno != EAGAIN) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return -errno; - } - } else - t->tcp_written += ss; - - /* Are we done? If so, disable the event source for EPOLLOUT */ - if (t->tcp_written >= sizeof(sz) + t->sent->size) { - r = sd_event_source_set_io_events(s, EPOLLIN); - if (r < 0) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return r; - } - } - } - - if (revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) { - - if (t->tcp_read < sizeof(t->tcp_read_size)) { - ssize_t ss; - - ss = read(fd, (uint8_t*) &t->tcp_read_size + t->tcp_read, sizeof(t->tcp_read_size) - t->tcp_read); - if (ss < 0) { - if (errno != EINTR && errno != EAGAIN) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return -errno; - } - } else if (ss == 0) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return -EIO; - } else - t->tcp_read += ss; - } - - if (t->tcp_read >= sizeof(t->tcp_read_size)) { - - if (be16toh(t->tcp_read_size) < DNS_PACKET_HEADER_SIZE) { - dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY); - return -EBADMSG; - } - - if (t->tcp_read < sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) { - ssize_t ss; - - if (!t->received) { - r = dns_packet_new(&t->received, t->scope->protocol, be16toh(t->tcp_read_size)); - if (r < 0) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return r; - } - } - - ss = read(fd, - (uint8_t*) DNS_PACKET_DATA(t->received) + t->tcp_read - sizeof(t->tcp_read_size), - sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size) - t->tcp_read); - if (ss < 0) { - if (errno != EINTR && errno != EAGAIN) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return -errno; - } - } else if (ss == 0) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return -EIO; - } else - t->tcp_read += ss; - } - - if (t->tcp_read >= sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) { - t->received->size = be16toh(t->tcp_read_size); - dns_query_transaction_process_reply(t, t->received); - return 0; - } - } - } - - return 0; -} - -static int dns_query_transaction_open_tcp(DnsQueryTransaction *t) { - int r; - - assert(t); - - if (t->scope->protocol == DNS_PROTOCOL_DNS) - return -ENOTSUP; - - if (t->tcp_fd >= 0) - return 0; - - t->tcp_written = 0; - t->tcp_read = 0; - t->received = dns_packet_unref(t->received); - - t->tcp_fd = dns_scope_tcp_socket(t->scope); - if (t->tcp_fd < 0) - return t->tcp_fd; - - r = sd_event_add_io(t->scope->manager->event, &t->tcp_event_source, t->tcp_fd, EPOLLIN|EPOLLOUT, on_tcp_ready, t); - if (r < 0) { - t->tcp_fd = safe_close(t->tcp_fd); - return r; - } - - return 0; -} - -void dns_query_transaction_process_reply(DnsQueryTransaction *t, DnsPacket *p) { - int r; - - assert(t); - assert(p); - assert(t->state == DNS_QUERY_PENDING); - - /* Note that this call might invalidate the query. Callers - * should hence not attempt to access the query or transaction - * after calling this function. */ - - if (t->received != p) { - dns_packet_unref(t->received); - t->received = dns_packet_ref(p); - } - - if (t->tcp_fd >= 0) { - if (DNS_PACKET_TC(p)) { - /* Truncated via TCP? Somebody must be fucking with us */ - dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY); - return; - } - - if (DNS_PACKET_ID(p) != t->id) { - /* Not the reply to our query? Somebody must be fucking with us */ - dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY); - return; - } - } - - if (DNS_PACKET_TC(p)) { - /* Response was truncated, let's try again with good old TCP */ - r = dns_query_transaction_open_tcp(t); - if (r == -ESRCH) { - /* No servers found? Damn! */ - dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS); - return; - } - if (r < 0) { - /* Couldn't send? Try immediately again, with a new server */ - dns_scope_next_dns_server(t->scope); - - r = dns_query_transaction_go(t); - if (r < 0) { - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - return; - } - - return; - } - } - - /* Parse and update the cache */ - r = dns_packet_extract(p); - if (r < 0) { - dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY); - return; - } else - dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, 0); - - if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS) - dns_query_transaction_complete(t, DNS_QUERY_SUCCESS); - else - dns_query_transaction_complete(t, DNS_QUERY_FAILURE); -} - -static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { - DnsQueryTransaction *t = userdata; - int r; - - assert(s); - assert(t); - - /* Timeout reached? Try again, with a new server */ - dns_scope_next_dns_server(t->scope); - - r = dns_query_transaction_go(t); - if (r < 0) - dns_query_transaction_complete(t, DNS_QUERY_RESOURCES); - - return 0; -} - -static int dns_query_make_packet(DnsQueryTransaction *t) { - _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - unsigned n, added = 0; - int r; - - assert(t); - - if (t->sent) - return 0; - - r = dns_packet_new_query(&p, t->scope->protocol, 0); - if (r < 0) - return r; - - for (n = 0; n < t->question->n_keys; n++) { - r = dns_scope_good_key(t->scope, t->question->keys[n]); - if (r < 0) - return r; - if (r == 0) - continue; - - r = dns_packet_append_key(p, t->question->keys[n], NULL); - if (r < 0) - return r; - - added++; - } - - if (added <= 0) - return -EDOM; - - DNS_PACKET_HEADER(p)->qdcount = htobe16(added); - DNS_PACKET_HEADER(p)->id = t->id; - - t->sent = p; - p = NULL; - - return 0; -} - -static int dns_query_transaction_go(DnsQueryTransaction *t) { - int r; - - assert(t); - - dns_query_transaction_stop(t); - - if (t->n_attempts >= ATTEMPTS_MAX) { - dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX); - return 0; - } - - t->n_attempts++; - t->received = dns_packet_unref(t->received); - t->cached = dns_answer_unref(t->cached); - t->cached_rcode = 0; - - /* First, let's try the cache */ - dns_cache_prune(&t->scope->cache); - r = dns_cache_lookup(&t->scope->cache, t->question, &t->cached_rcode, &t->cached); - if (r < 0) - return r; - if (r > 0) { - if (t->cached_rcode == DNS_RCODE_SUCCESS) - dns_query_transaction_complete(t, DNS_QUERY_SUCCESS); - else - dns_query_transaction_complete(t, DNS_QUERY_FAILURE); - return 0; - } - - /* Otherwise, we need to ask the network */ - r = dns_query_make_packet(t); - if (r == -EDOM) { - /* Not the right request to make on this network? - * (i.e. an A request made on IPv6 or an AAAA request - * made on IPv4, on LLMNR or mDNS.) */ - dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS); - return 0; - } - if (r < 0) - return r; - - /* Try via UDP, and if that fails due to large size try via TCP */ - r = dns_scope_send(t->scope, t->sent); - if (r == -EMSGSIZE) - r = dns_query_transaction_open_tcp(t); - if (r == -ESRCH) { - /* No servers to send this to? */ - dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS); - return 0; - } - if (r < 0) { - /* Couldn't send? Try immediately again, with a new server */ - dns_scope_next_dns_server(t->scope); + q->timeout_event_source = sd_event_source_unref(q->timeout_event_source); - return dns_query_transaction_go(t); + while ((t = set_steal_first(q->transactions))) { + set_remove(t->queries, q); + dns_transaction_gc(t); } - - r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t); - if (r < 0) - return r; - - t->state = DNS_QUERY_PENDING; - return 1; } DnsQuery *dns_query_free(DnsQuery *q) { - DnsQueryTransaction *t; - if (!q) return NULL; - sd_bus_message_unref(q->request); + dns_query_stop(q); + set_free(q->transactions); dns_question_unref(q->question); dns_answer_unref(q->answer); - sd_event_source_unref(q->timeout_event_source); - - while ((t = set_steal_first(q->transactions))) { - set_remove(t->queries, q); - dns_query_transaction_gc(t); - } - - set_free(q->transactions); + sd_bus_message_unref(q->request); if (q->manager) { LIST_REMOVE(queries, q->manager->dns_queries, q); @@ -519,10 +87,13 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question) { q->question = dns_question_ref(question); for (i = 0; i < question->n_keys; i++) { - log_debug("Looking up RR for %s %s %s", - strna(dns_class_to_string(question->keys[i]->class)), - strna(dns_type_to_string(question->keys[i]->type)), - DNS_RESOURCE_KEY_NAME(question->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); @@ -536,23 +107,10 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question) { return 0; } -static void dns_query_stop(DnsQuery *q) { - DnsQueryTransaction *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_query_transaction_gc(t); - } -} - -static void dns_query_complete(DnsQuery *q, DnsQueryState state) { +static void dns_query_complete(DnsQuery *q, DnsTransactionState state) { assert(q); - assert(!IN_SET(state, DNS_QUERY_NULL, DNS_QUERY_PENDING)); - assert(IN_SET(q->state, DNS_QUERY_NULL, DNS_QUERY_PENDING)); + 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 @@ -571,62 +129,99 @@ static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) { assert(s); assert(q); - dns_query_complete(q, DNS_QUERY_TIMEOUT); + dns_query_complete(q, DNS_TRANSACTION_TIMEOUT); return 0; } -static int dns_query_add_transaction(DnsQuery *q, DnsScope *s) { - DnsQueryTransaction *t; +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, NULL); if (r < 0) return r; - LIST_FOREACH(transactions_by_scope, t, s->transactions) - if (dns_question_is_superset(t->question, q->question)) - break; + 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); if (!t) { - r = dns_query_transaction_new(&t, s, q->question); + r = dns_transaction_new(&t, s, question); if (r < 0) return r; } r = set_ensure_allocated(&t->queries, NULL, NULL); if (r < 0) - goto fail; + goto gc; r = set_put(t->queries, q); if (r < 0) - goto fail; + goto gc; r = set_put(q->transactions, t); if (r < 0) { set_remove(t->queries, q); - goto fail; + goto gc; } return 0; -fail: - dns_query_transaction_gc(t); +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; - DnsQueryTransaction *t; + DnsTransaction *t; const char *name; Iterator i; int r; assert(q); - if (q->state != DNS_QUERY_NULL) + if (q->state != DNS_TRANSACTION_NULL) return 0; assert(q->question); @@ -660,42 +255,49 @@ int dns_query_go(DnsQuery *q) { if (found == DNS_SCOPE_NO) return -ESRCH; - r = dns_query_add_transaction(q, first); + r = dns_query_add_transaction_split(q, first); if (r < 0) - return r; + goto fail; LIST_FOREACH(scopes, s, first->scopes_next) { DnsScopeMatch match; match = dns_scope_good_domain(s, name); if (match < 0) - return match; + goto fail; if (match != found) continue; - r = dns_query_add_transaction(q, s); + r = dns_query_add_transaction_split(q, s); if (r < 0) - return r; + goto fail; } q->answer = dns_answer_unref(q->answer); q->answer_ifindex = 0; q->answer_rcode = 0; - r = sd_event_add_time(q->manager->event, &q->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + QUERY_TIMEOUT_USEC, 0, on_query_timeout, 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; - q->state = DNS_QUERY_PENDING; + 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_QUERY_NULL) { - r = dns_query_transaction_go(t); - if (r < 0) - goto fail; - } + if (t->state != DNS_TRANSACTION_NULL) + continue; + + r = dns_transaction_go(t); + if (r < 0) + goto fail; } q->block_ready--; @@ -709,14 +311,16 @@ fail: } void dns_query_ready(DnsQuery *q) { - DnsQueryTransaction *t; - DnsQueryState state = DNS_QUERY_NO_SERVERS; - DnsAnswer *failure_answer = NULL; - int failure_rcode = 0, failure_ifindex = 0; + 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_QUERY_NULL, DNS_QUERY_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 @@ -728,53 +332,95 @@ void dns_query_ready(DnsQuery *q) { SET_FOREACH(t, q->transactions, i) { - /* One of the transactions is still going on, let's wait for it */ - if (t->state == DNS_QUERY_PENDING || t->state == DNS_QUERY_NULL) - return; + /* 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_QUERY_SUCCESS) { + if (t->state == DNS_TRANSACTION_SUCCESS) { + DnsAnswer *a; + if (t->received) { - q->answer = dns_answer_ref(t->received->answer); - q->answer_ifindex = t->received->ifindex; - q->answer_rcode = DNS_PACKET_RCODE(t->received); + rcode = DNS_PACKET_RCODE(t->received); + a = t->received->answer; } else { - q->answer = dns_answer_ref(t->cached); - q->answer_ifindex = t->scope->link ? t->scope->link->ifindex : 0; - q->answer_rcode = t->cached_rcode; + rcode = t->cached_rcode; + a = t->cached; } - dns_query_complete(q, DNS_QUERY_SUCCESS); - return; + 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 packet */ - if (t->state == DNS_QUERY_FAILURE) { + * its response data */ + if (state != DNS_TRANSACTION_SUCCESS && t->state == DNS_TRANSACTION_FAILURE) { + DnsAnswer *a; + if (t->received) { - failure_answer = t->received->answer; - failure_ifindex = t->received->ifindex; - failure_rcode = DNS_PACKET_RCODE(t->received); + rcode = DNS_PACKET_RCODE(t->received); + a = t->received->answer; } else { - failure_answer = t->cached; - failure_ifindex = t->scope->link ? t->scope->link->ifindex : 0; - failure_rcode = t->cached_rcode; + rcode = t->cached_rcode; + a = t->cached; } - state = DNS_QUERY_FAILURE; + dns_answer_unref(answer); + answer = dns_answer_ref(a); + + scope = t->scope; + state = DNS_TRANSACTION_FAILURE; continue; } - if (state == DNS_QUERY_NO_SERVERS && t->state != DNS_QUERY_NO_SERVERS) + if (state == DNS_TRANSACTION_NO_SERVERS && t->state != DNS_TRANSACTION_NO_SERVERS) state = t->state; } - if (state == DNS_QUERY_FAILURE) { - q->answer = dns_answer_ref(failure_answer); - q->answer_ifindex = failure_ifindex; - q->answer_rcode = failure_rcode; + 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; } dns_query_complete(q, state); @@ -800,7 +446,7 @@ int dns_query_cname_redirect(DnsQuery *q, const char *name) { q->n_cname_redirects++; dns_query_stop(q); - q->state = DNS_QUERY_NULL; + q->state = DNS_TRANSACTION_NULL; return 0; }