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_RCODE_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_CONNECTION_FAILURE,
  40         DNS_TRANSACTION_ABORTED,
  41         DNS_TRANSACTION_DNSSEC_FAILED,
  42         DNS_TRANSACTION_NO_TRUST_ANCHOR,
  43         _DNS_TRANSACTION_STATE_MAX,
  44         _DNS_TRANSACTION_STATE_INVALID = -1
  45 };
  46
  47 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  48
  49 enum DnsTransactionSource {
  50         DNS_TRANSACTION_NETWORK,
  51         DNS_TRANSACTION_CACHE,
  52         DNS_TRANSACTION_ZONE,
  53         DNS_TRANSACTION_TRUST_ANCHOR,
  54         _DNS_TRANSACTION_SOURCE_MAX,
  55         _DNS_TRANSACTION_SOURCE_INVALID = -1
  56 };
  57
  58 #include "resolved-dns-answer.h"
  59 #include "resolved-dns-packet.h"
  60 #include "resolved-dns-question.h"
  61 #include "resolved-dns-scope.h"
  62
  63 struct DnsTransaction {
  64         DnsScope *scope;
  65
  66         DnsResourceKey *key;
  67         char *key_string;
  68
  69         DnsTransactionState state;
  70
  71         uint16_t id;
  72
  73         bool tried_stream:1;
  74
  75         bool initial_jitter_scheduled:1;
  76         bool initial_jitter_elapsed:1;
  77
  78         DnsPacket *sent, *received;
  79
  80         DnsAnswer *answer;
  81         int answer_rcode;
  82         DnssecResult answer_dnssec_result;
  83         DnsTransactionSource answer_source;
  84
  85         /* Indicates whether the primary answer is authenticated,
  86          * i.e. whether the RRs from answer which directly match the
  87          * question are authenticated, or, if there are none, whether
  88          * the NODATA or NXDOMAIN case is. It says nothing about
  89          * additional RRs listed in the answer, however they have
  90          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  91          * is defined different than the AD bit in DNS packets, as
  92          * that covers more than just the actual primary answer. */
  93         bool answer_authenticated;
  94
  95         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  96          * to authenticate this reply */
  97         DnsAnswer *validated_keys;
  98
  99         usec_t start_usec;
 100         usec_t next_attempt_after;
 101         sd_event_source *timeout_event_source;
 102         unsigned n_attempts;
 103
 104         /* UDP connection logic, if we need it */
 105         int dns_udp_fd;
 106         sd_event_source *dns_udp_event_source;
 107
 108         /* TCP connection logic, if we need it */
 109         DnsStream *stream;
 110
 111         /* The active server */
 112         DnsServer *server;
 113
 114         /* The features of the DNS server at time of transaction start */
 115         DnsServerFeatureLevel current_features;
 116
 117         /* Query candidates this transaction is referenced by and that
 118          * shall be notified about this specific transaction
 119          * completing. */
 120         Set *notify_query_candidates;
 121
 122         /* Zone items this transaction is referenced by and that shall
 123          * be notified about completion. */
 124         Set *notify_zone_items;
 125
 126         /* Other transactions that this transactions is referenced by
 127          * and that shall be notified about completion. This is used
 128          * when transactions want to validate their RRsets, but need
 129          * another DNSKEY or DS RR to do so. */
 130         Set *notify_transactions;
 131
 132         /* The opposite direction: the transactions this transaction
 133          * created in order to request DNSKEY or DS RRs. */
 134         Set *dnssec_transactions;
 135
 136         unsigned block_gc;
 137
 138         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 139 };
 140
 141 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 142 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 143
 144 bool dns_transaction_gc(DnsTransaction *t);
 145 int dns_transaction_go(DnsTransaction *t);
 146
 147 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 148 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 149
 150 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 151 int dns_transaction_validate_dnssec(DnsTransaction *t);
 152 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 153
 154 const char *dns_transaction_key_string(DnsTransaction *t);
 155
 156 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 157 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 158
 159 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 160 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 161
 162 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 163 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 164
 165 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 166 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 167 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 168
 169 /* Maximum attempts to send DNS requests, across all DNS servers */
 170 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 171
 172 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 173 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 174
 175 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)