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_ERRNO,
  39         DNS_TRANSACTION_ABORTED,
  40         DNS_TRANSACTION_DNSSEC_FAILED,
  41         DNS_TRANSACTION_NO_TRUST_ANCHOR,
  42         DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
  43         DNS_TRANSACTION_NETWORK_DOWN,
  44         DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
  45         _DNS_TRANSACTION_STATE_MAX,
  46         _DNS_TRANSACTION_STATE_INVALID = -1
  47 };
  48
  49 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  50
  51 enum DnsTransactionSource {
  52         DNS_TRANSACTION_NETWORK,
  53         DNS_TRANSACTION_CACHE,
  54         DNS_TRANSACTION_ZONE,
  55         DNS_TRANSACTION_TRUST_ANCHOR,
  56         _DNS_TRANSACTION_SOURCE_MAX,
  57         _DNS_TRANSACTION_SOURCE_INVALID = -1
  58 };
  59
  60 #include "resolved-dns-answer.h"
  61 #include "resolved-dns-packet.h"
  62 #include "resolved-dns-question.h"
  63 #include "resolved-dns-scope.h"
  64
  65 struct DnsTransaction {
  66         DnsScope *scope;
  67
  68         DnsResourceKey *key;
  69         char *key_string;
  70
  71         DnsTransactionState state;
  72
  73         uint16_t id;
  74
  75         bool tried_stream:1;
  76
  77         bool initial_jitter_scheduled:1;
  78         bool initial_jitter_elapsed:1;
  79
  80         DnsPacket *sent, *received;
  81
  82         DnsAnswer *answer;
  83         int answer_rcode;
  84         DnssecResult answer_dnssec_result;
  85         DnsTransactionSource answer_source;
  86         uint32_t answer_nsec_ttl;
  87         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  88
  89         /* Indicates whether the primary answer is authenticated,
  90          * i.e. whether the RRs from answer which directly match the
  91          * question are authenticated, or, if there are none, whether
  92          * the NODATA or NXDOMAIN case is. It says nothing about
  93          * additional RRs listed in the answer, however they have
  94          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  95          * is defined different than the AD bit in DNS packets, as
  96          * that covers more than just the actual primary answer. */
  97         bool answer_authenticated;
  98
  99         /* Contains DNSKEY, DS, SOA RRs we already verified and need
 100          * to authenticate this reply */
 101         DnsAnswer *validated_keys;
 102
 103         usec_t start_usec;
 104         usec_t next_attempt_after;
 105         sd_event_source *timeout_event_source;
 106         unsigned n_attempts;
 107
 108         /* UDP connection logic, if we need it */
 109         int dns_udp_fd;
 110         sd_event_source *dns_udp_event_source;
 111
 112         /* TCP connection logic, if we need it */
 113         DnsStream *stream;
 114
 115         /* The active server */
 116         DnsServer *server;
 117
 118         /* The features of the DNS server at time of transaction start */
 119         DnsServerFeatureLevel current_feature_level;
 120
 121         /* Query candidates this transaction is referenced by and that
 122          * shall be notified about this specific transaction
 123          * completing. */
 124         Set *notify_query_candidates;
 125
 126         /* Zone items this transaction is referenced by and that shall
 127          * be notified about completion. */
 128         Set *notify_zone_items;
 129
 130         /* Other transactions that this transactions is referenced by
 131          * and that shall be notified about completion. This is used
 132          * when transactions want to validate their RRsets, but need
 133          * another DNSKEY or DS RR to do so. */
 134         Set *notify_transactions;
 135
 136         /* The opposite direction: the transactions this transaction
 137          * created in order to request DNSKEY or DS RRs. */
 138         Set *dnssec_transactions;
 139
 140         unsigned block_gc;
 141
 142         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 143 };
 144
 145 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 146 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 147
 148 bool dns_transaction_gc(DnsTransaction *t);
 149 int dns_transaction_go(DnsTransaction *t);
 150
 151 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 152 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 153
 154 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 155 int dns_transaction_validate_dnssec(DnsTransaction *t);
 156 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 157
 158 const char *dns_transaction_key_string(DnsTransaction *t);
 159
 160 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 161 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 162
 163 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 164 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 165
 166 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 167 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 168
 169 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 170 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 171 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 172
 173 /* Maximum attempts to send DNS requests, across all DNS servers */
 174 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 175
 176 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 177 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 178
 179 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)