src/resolve/resolved-dns-transaction.h

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 #pragma once
   4
   5 /***
   6   This file is part of systemd.
   7
   8   Copyright 2014 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 ***/
  23
  24 typedef struct DnsTransaction DnsTransaction;
  25 typedef enum DnsTransactionState DnsTransactionState;
  26 typedef enum DnsTransactionSource DnsTransactionSource;
  27
  28 enum DnsTransactionState {
  29         DNS_TRANSACTION_NULL,
  30         DNS_TRANSACTION_PENDING,
  31         DNS_TRANSACTION_FAILURE,
  32         DNS_TRANSACTION_SUCCESS,
  33         DNS_TRANSACTION_NO_SERVERS,
  34         DNS_TRANSACTION_TIMEOUT,
  35         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  36         DNS_TRANSACTION_INVALID_REPLY,
  37         DNS_TRANSACTION_RESOURCES,
  38         DNS_TRANSACTION_ABORTED,
  39         _DNS_TRANSACTION_STATE_MAX,
  40         _DNS_TRANSACTION_STATE_INVALID = -1
  41 };
  42
  43 enum DnsTransactionSource {
  44         DNS_TRANSACTION_NETWORK,
  45         DNS_TRANSACTION_CACHE,
  46         DNS_TRANSACTION_ZONE,
  47         DNS_TRANSACTION_TRUST_ANCHOR,
  48         _DNS_TRANSACTION_SOURCE_MAX,
  49         _DNS_TRANSACTION_SOURCE_INVALID = -1
  50 };
  51
  52 #include "resolved-dns-answer.h"
  53 #include "resolved-dns-packet.h"
  54 #include "resolved-dns-question.h"
  55 #include "resolved-dns-scope.h"
  56
  57 struct DnsTransaction {
  58         DnsScope *scope;
  59
  60         DnsResourceKey *key;
  61
  62         DnsTransactionState state;
  63         uint16_t id;
  64
  65         bool initial_jitter;
  66
  67         DnsPacket *sent, *received;
  68
  69         DnsAnswer *answer;
  70         int answer_rcode;
  71         DnsTransactionSource answer_source;
  72         bool answer_authenticated;
  73
  74         usec_t start_usec;
  75         sd_event_source *timeout_event_source;
  76         unsigned n_attempts;
  77
  78         int dns_udp_fd;
  79         sd_event_source *dns_udp_event_source;
  80
  81         /* The active server */
  82         DnsServer *server;
  83
  84         /* the features of the DNS server at time of transaction start */
  85         DnsServerFeatureLevel current_features;
  86
  87         /* TCP connection logic, if we need it */
  88         DnsStream *stream;
  89
  90         /* Query candidates this transaction is referenced by and that
  91          * shall be notified about this specific transaction
  92          * completing. */
  93         Set *query_candidates;
  94
  95         /* Zone items this transaction is referenced by and that shall
  96          * be notified about completion. */
  97         Set *zone_items;
  98
  99         unsigned block_gc;
 100
 101         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 102 };
 103
 104 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 105 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 106
 107 void dns_transaction_gc(DnsTransaction *t);
 108 int dns_transaction_go(DnsTransaction *t);
 109
 110 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 111 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 112
 113 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 114 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 115
 116 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 117 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 118
 119 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 120 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 121
 122 /* Maximum attempts to send DNS requests, across all DNS servers */
 123 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 124
 125 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 126 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 127
 128 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)