src/resolve/resolved-dns-transaction.h

   1 #pragma once
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2014 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 typedef struct DnsTransaction DnsTransaction;
  23 typedef enum DnsTransactionState DnsTransactionState;
  24 typedef enum DnsTransactionSource DnsTransactionSource;
  25
  26 enum DnsTransactionState {
  27         DNS_TRANSACTION_NULL,
  28         DNS_TRANSACTION_PENDING,
  29         DNS_TRANSACTION_VALIDATING,
  30         DNS_TRANSACTION_RCODE_FAILURE,
  31         DNS_TRANSACTION_SUCCESS,
  32         DNS_TRANSACTION_NO_SERVERS,
  33         DNS_TRANSACTION_TIMEOUT,
  34         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  35         DNS_TRANSACTION_INVALID_REPLY,
  36         DNS_TRANSACTION_ERRNO,
  37         DNS_TRANSACTION_ABORTED,
  38         DNS_TRANSACTION_DNSSEC_FAILED,
  39         DNS_TRANSACTION_NO_TRUST_ANCHOR,
  40         DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
  41         DNS_TRANSACTION_NETWORK_DOWN,
  42         DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
  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
  68         DnsTransactionState state;
  69
  70         uint16_t id;
  71
  72         bool tried_stream:1;
  73
  74         bool initial_jitter_scheduled:1;
  75         bool initial_jitter_elapsed:1;
  76
  77         DnsPacket *sent, *received;
  78
  79         DnsAnswer *answer;
  80         int answer_rcode;
  81         DnssecResult answer_dnssec_result;
  82         DnsTransactionSource answer_source;
  83         uint32_t answer_nsec_ttl;
  84         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  85
  86         /* Indicates whether the primary answer is authenticated,
  87          * i.e. whether the RRs from answer which directly match the
  88          * question are authenticated, or, if there are none, whether
  89          * the NODATA or NXDOMAIN case is. It says nothing about
  90          * additional RRs listed in the answer, however they have
  91          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  92          * is defined different than the AD bit in DNS packets, as
  93          * that covers more than just the actual primary answer. */
  94         bool answer_authenticated;
  95
  96         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  97          * to authenticate this reply */
  98         DnsAnswer *validated_keys;
  99
 100         usec_t start_usec;
 101         usec_t next_attempt_after;
 102         sd_event_source *timeout_event_source;
 103         unsigned n_attempts;
 104
 105         /* UDP connection logic, if we need it */
 106         int dns_udp_fd;
 107         sd_event_source *dns_udp_event_source;
 108
 109         /* TCP connection logic, if we need it */
 110         DnsStream *stream;
 111
 112         /* The active server */
 113         DnsServer *server;
 114
 115         /* The features of the DNS server at time of transaction start */
 116         DnsServerFeatureLevel current_feature_level;
 117
 118         /* Query candidates this transaction is referenced by and that
 119          * shall be notified about this specific transaction
 120          * completing. */
 121         Set *notify_query_candidates;
 122
 123         /* Zone items this transaction is referenced by and that shall
 124          * be notified about completion. */
 125         Set *notify_zone_items;
 126
 127         /* Other transactions that this transactions is referenced by
 128          * and that shall be notified about completion. This is used
 129          * when transactions want to validate their RRsets, but need
 130          * another DNSKEY or DS RR to do so. */
 131         Set *notify_transactions;
 132
 133         /* The opposite direction: the transactions this transaction
 134          * created in order to request DNSKEY or DS RRs. */
 135         Set *dnssec_transactions;
 136
 137         unsigned block_gc;
 138
 139         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 140 };
 141
 142 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 143 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 144
 145 bool dns_transaction_gc(DnsTransaction *t);
 146 int dns_transaction_go(DnsTransaction *t);
 147
 148 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 149 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 150
 151 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 152 int dns_transaction_validate_dnssec(DnsTransaction *t);
 153 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 154
 155 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 156 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 157
 158 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 159 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 160
 161 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 162 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 163
 164 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 165 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 166 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 167
 168 /* Maximum attempts to send DNS requests, across all DNS servers */
 169 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 170
 171 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 172 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 173
 174 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)