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_SOURCE_MAX,
  48         _DNS_TRANSACTION_SOURCE_INVALID = -1
  49 };
  50
  51 #include "resolved-dns-answer.h"
  52 #include "resolved-dns-packet.h"
  53 #include "resolved-dns-question.h"
  54 #include "resolved-dns-scope.h"
  55
  56 struct DnsTransaction {
  57         DnsScope *scope;
  58
  59         DnsResourceKey *key;
  60
  61         DnsTransactionState state;
  62         uint16_t id;
  63
  64         bool initial_jitter;
  65
  66         DnsPacket *sent, *received;
  67
  68         DnsAnswer *answer;
  69         int answer_rcode;
  70         DnsTransactionSource answer_source;
  71
  72         usec_t start_usec;
  73         sd_event_source *timeout_event_source;
  74         unsigned n_attempts;
  75
  76         int dns_udp_fd;
  77         sd_event_source *dns_udp_event_source;
  78
  79         /* The active server */
  80         DnsServer *server;
  81
  82         /* the features of the DNS server at time of transaction start */
  83         DnsServerFeatureLevel current_features;
  84
  85         /* TCP connection logic, if we need it */
  86         DnsStream *stream;
  87
  88         /* Query candidates this transaction is referenced by and that
  89          * shall be notified about this specific transaction
  90          * completing. */
  91         Set *query_candidates;
  92
  93         /* Zone items this transaction is referenced by and that shall
  94          * be notified about completion. */
  95         Set *zone_items;
  96
  97         unsigned block_gc;
  98
  99         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 100 };
 101
 102 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 103 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 104
 105 void dns_transaction_gc(DnsTransaction *t);
 106 int dns_transaction_go(DnsTransaction *t);
 107
 108 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 109 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 110
 111 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 112 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 113
 114 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 115 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 116
 117 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 118 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 119
 120 /* Maximum attempts to send DNS requests, across all DNS servers */
 121 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 122
 123 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 124 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 125
 126 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)