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_scheduled;
  66         bool initial_jitter_elapsed;
  67
  68         DnsPacket *sent, *received;
  69
  70         DnsAnswer *answer;
  71         int answer_rcode;
  72         DnsTransactionSource answer_source;
  73         bool answer_authenticated;
  74
  75         usec_t start_usec;
  76         usec_t next_attempt_after;
  77         sd_event_source *timeout_event_source;
  78         unsigned n_attempts;
  79
  80         int dns_udp_fd;
  81         sd_event_source *dns_udp_event_source;
  82
  83         /* The active server */
  84         DnsServer *server;
  85
  86         /* the features of the DNS server at time of transaction start */
  87         DnsServerFeatureLevel current_features;
  88
  89         /* TCP connection logic, if we need it */
  90         DnsStream *stream;
  91
  92         /* Query candidates this transaction is referenced by and that
  93          * shall be notified about this specific transaction
  94          * completing. */
  95         Set *query_candidates;
  96
  97         /* Zone items this transaction is referenced by and that shall
  98          * be notified about completion. */
  99         Set *zone_items;
 100
 101         unsigned block_gc;
 102
 103         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 104 };
 105
 106 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 107 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 108
 109 void dns_transaction_gc(DnsTransaction *t);
 110 int dns_transaction_go(DnsTransaction *t);
 111
 112 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 113 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 114
 115 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 116 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 117
 118 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 119 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 120
 121 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 122 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 123
 124 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 125 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 126 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 127
 128 /* Maximum attempts to send DNS requests, across all DNS servers */
 129 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 130
 131 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 132 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 133
 134 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)