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_VALIDATING,
  32         DNS_TRANSACTION_FAILURE,
  33         DNS_TRANSACTION_SUCCESS,
  34         DNS_TRANSACTION_NO_SERVERS,
  35         DNS_TRANSACTION_TIMEOUT,
  36         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  37         DNS_TRANSACTION_INVALID_REPLY,
  38         DNS_TRANSACTION_RESOURCES,
  39         DNS_TRANSACTION_ABORTED,
  40         DNS_TRANSACTION_DNSSEC_FAILED,
  41         _DNS_TRANSACTION_STATE_MAX,
  42         _DNS_TRANSACTION_STATE_INVALID = -1
  43 };
  44
  45 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  46
  47 enum DnsTransactionSource {
  48         DNS_TRANSACTION_NETWORK,
  49         DNS_TRANSACTION_CACHE,
  50         DNS_TRANSACTION_ZONE,
  51         DNS_TRANSACTION_TRUST_ANCHOR,
  52         _DNS_TRANSACTION_SOURCE_MAX,
  53         _DNS_TRANSACTION_SOURCE_INVALID = -1
  54 };
  55
  56 #include "resolved-dns-answer.h"
  57 #include "resolved-dns-packet.h"
  58 #include "resolved-dns-question.h"
  59 #include "resolved-dns-scope.h"
  60
  61 struct DnsTransaction {
  62         DnsScope *scope;
  63
  64         DnsResourceKey *key;
  65         char *key_string;
  66
  67         DnsTransactionState state;
  68         DnssecResult dnssec_result;
  69
  70         uint16_t id;
  71
  72         bool initial_jitter_scheduled;
  73         bool initial_jitter_elapsed;
  74
  75         DnsPacket *sent, *received;
  76
  77         DnsAnswer *answer;
  78         unsigned n_answer_cacheable; /* Specifies how many RRs of the answer shall be cached, from the beginning */
  79         int answer_rcode;
  80         DnsTransactionSource answer_source;
  81         bool answer_authenticated;
  82
  83         /* Contains DS and DNSKEY RRs we already verified and need to authenticate this reply */
  84         DnsAnswer *validated_keys;
  85
  86         usec_t start_usec;
  87         usec_t next_attempt_after;
  88         sd_event_source *timeout_event_source;
  89         unsigned n_attempts;
  90
  91         int dns_udp_fd;
  92         sd_event_source *dns_udp_event_source;
  93
  94         /* The active server */
  95         DnsServer *server;
  96
  97         /* The features of the DNS server at time of transaction start */
  98         DnsServerFeatureLevel current_features;
  99
 100         /* TCP connection logic, if we need it */
 101         DnsStream *stream;
 102
 103         /* Query candidates this transaction is referenced by and that
 104          * shall be notified about this specific transaction
 105          * completing. */
 106         Set *notify_query_candidates;
 107
 108         /* Zone items this transaction is referenced by and that shall
 109          * be notified about completion. */
 110         Set *notify_zone_items;
 111
 112         /* Other transactions that this transactions is referenced by
 113          * and that shall be notified about completion. This is used
 114          * when transactions want to validate their RRsets, but need
 115          * another DNSKEY or DS RR to do so. */
 116         Set *notify_transactions;
 117
 118         /* The opposite direction: the transactions this transaction
 119          * created in order to request DNSKEY or DS RRs. */
 120         Set *dnssec_transactions;
 121
 122         unsigned block_gc;
 123
 124         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 125 };
 126
 127 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 128 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 129
 130 void dns_transaction_gc(DnsTransaction *t);
 131 int dns_transaction_go(DnsTransaction *t);
 132
 133 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 134 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 135
 136 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 137 int dns_transaction_validate_dnssec(DnsTransaction *t);
 138 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 139
 140 const char *dns_transaction_key_string(DnsTransaction *t);
 141
 142 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 143 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 144
 145 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 146 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 147
 148 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 149 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 150
 151 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 152 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 153 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 154
 155 /* Maximum attempts to send DNS requests, across all DNS servers */
 156 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 157
 158 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 159 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 160
 161 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)