resolved: implement LLMNR uniqueness verification

1 files changed, 108 insertions, 0 deletions

diff --git a/src/resolve/resolved-dns-transaction.h b/src/resolve/resolved-dns-transaction.h
new file mode 100644
index 0000000000..d825b3ec85
--- /dev/null
+++ b/src/resolve/resolved-dns-transaction.h
@@ -0,0 +1,108 @@
+/*-*- 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)