- 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);