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+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ 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/>.
+***/
+
+typedef struct DnsTransaction DnsTransaction;
+typedef enum DnsTransactionState DnsTransactionState;
+
+enum DnsTransactionState {
+ DNS_TRANSACTION_NULL,
+ DNS_TRANSACTION_PENDING,
+ DNS_TRANSACTION_FAILURE,
+ DNS_TRANSACTION_SUCCESS,
+ DNS_TRANSACTION_NO_SERVERS,
+ DNS_TRANSACTION_TIMEOUT,
+ DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
+ DNS_TRANSACTION_INVALID_REPLY,
+ DNS_TRANSACTION_RESOURCES,
+ DNS_TRANSACTION_ABORTED,
+ _DNS_TRANSACTION_STATE_MAX,
+ _DNS_TRANSACTION_STATE_INVALID = -1
+};
+
+#include "resolved-dns-scope.h"
+#include "resolved-dns-rr.h"
+#include "resolved-dns-packet.h"
+#include "resolved-dns-question.h"
+#include "resolved-dns-answer.h"
+#include "resolved-dns-stream.h"
+
+struct DnsTransaction {
+ DnsScope *scope;
+
+ DnsQuestion *question;
+
+ DnsTransactionState state;
+ uint16_t id;
+
+ DnsPacket *sent, *received;
+ DnsAnswer *cached;
+ int cached_rcode;
+
+ sd_event_source *timeout_event_source;
+ unsigned n_attempts;
+
+ /* TCP connection logic, if we need it */
+ DnsStream *stream;
+
+ /* Queries this transaction is referenced by and that shall be
+ * notified about this specific transaction completing. */
+ Set *queries;
+
+ /* Zone items this transaction is referenced by and that shall
+ * be notified about completion. */
+ Set *zone_items;
+
+ unsigned block_gc;
+
+ LIST_FIELDS(DnsTransaction, transactions_by_scope);
+};
+
+int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsQuestion *q);
+DnsTransaction* dns_transaction_free(DnsTransaction *t);
+
+void dns_transaction_gc(DnsTransaction *t);
+int dns_transaction_go(DnsTransaction *t);
+
+void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
+void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
+
+const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
+DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
+
+/* After how much time to repeat classic DNS requests */
+#define DNS_TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+
+/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
+#define LLMNR_TRANSACTION_TIMEOUT_USEC (1 * USEC_PER_SEC)
+
+/* LLMNR Jitter interval, see RFC 4795 Section 7 */
+#define LLMNR_TRANSACTION_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
+
+/* Maximum attempts to send DNS requests, across all DNS servers */
+#define DNS_TRANSACTION_ATTEMPTS_MAX 8
+
+/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
+#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
+
+#define TRANSACTION_TIMEOUT_USEC(p) (p == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_TIMEOUT_USEC : DNS_TRANSACTION_TIMEOUT_USEC)
+#define TRANSACTION_ATTEMPTS_MAX(p) (p == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)