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 #include "resolved-dns-server.h"
  63 #include "resolved-dns-stream.h"
  64
  65 struct DnsTransaction {
  66         DnsScope *scope;
  67
  68         DnsResourceKey *key;
  69
  70         DnsTransactionState state;
  71
  72         uint16_t id;
  73
  74         bool tried_stream:1;
  75
  76         bool initial_jitter_scheduled:1;
  77         bool initial_jitter_elapsed:1;
  78
  79         bool clamp_ttl:1;
  80
  81         bool probing:1;
  82
  83         DnsPacket *sent, *received;
  84
  85         DnsAnswer *answer;
  86         int answer_rcode;
  87         DnssecResult answer_dnssec_result;
  88         DnsTransactionSource answer_source;
  89         uint32_t answer_nsec_ttl;
  90         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  91
  92         /* Indicates whether the primary answer is authenticated,
  93          * i.e. whether the RRs from answer which directly match the
  94          * question are authenticated, or, if there are none, whether
  95          * the NODATA or NXDOMAIN case is. It says nothing about
  96          * additional RRs listed in the answer, however they have
  97          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  98          * is defined different than the AD bit in DNS packets, as
  99          * that covers more than just the actual primary answer. */
 100         bool answer_authenticated;
 101
 102         /* Contains DNSKEY, DS, SOA RRs we already verified and need
 103          * to authenticate this reply */
 104         DnsAnswer *validated_keys;
 105
 106         usec_t start_usec;
 107         usec_t next_attempt_after;
 108         sd_event_source *timeout_event_source;
 109         unsigned n_attempts;
 110
 111         /* UDP connection logic, if we need it */
 112         int dns_udp_fd;
 113         sd_event_source *dns_udp_event_source;
 114
 115         /* TCP connection logic, if we need it */
 116         DnsStream *stream;
 117
 118         /* The active server */
 119         DnsServer *server;
 120
 121         /* The features of the DNS server at time of transaction start */
 122         DnsServerFeatureLevel current_feature_level;
 123
 124         /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
 125         DnsServerFeatureLevel clamp_feature_level;
 126
 127         /* Query candidates this transaction is referenced by and that
 128          * shall be notified about this specific transaction
 129          * completing. */
 130         Set *notify_query_candidates, *notify_query_candidates_done;
 131
 132         /* Zone items this transaction is referenced by and that shall
 133          * be notified about completion. */
 134         Set *notify_zone_items, *notify_zone_items_done;
 135
 136         /* Other transactions that this transactions is referenced by
 137          * and that shall be notified about completion. This is used
 138          * when transactions want to validate their RRsets, but need
 139          * another DNSKEY or DS RR to do so. */
 140         Set *notify_transactions, *notify_transactions_done;
 141
 142         /* The opposite direction: the transactions this transaction
 143          * created in order to request DNSKEY or DS RRs. */
 144         Set *dnssec_transactions;
 145
 146         unsigned block_gc;
 147
 148         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 149 };
 150
 151 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 152 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 153
 154 bool dns_transaction_gc(DnsTransaction *t);
 155 int dns_transaction_go(DnsTransaction *t);
 156
 157 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 158 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 159
 160 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 161 int dns_transaction_validate_dnssec(DnsTransaction *t);
 162 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 163
 164 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 165 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 166
 167 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 168 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 169
 170 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 171 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 172
 173 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 174 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 175 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 176
 177 /* mDNS probing interval, see RFC 6762 Section 8.1 */
 178 #define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
 179
 180 /* Maximum attempts to send DNS requests, across all DNS servers */
 181 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 182
 183 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 184 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 185
 186 /* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
 187 #define MDNS_TRANSACTION_ATTEMPTS_MAX 3
 188
 189 #define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
 190                                          LLMNR_TRANSACTION_ATTEMPTS_MAX : \
 191                                          (((p) == DNS_PROTOCOL_MDNS) ? \
 192                                              MDNS_TRANSACTION_ATTEMPTS_MAX : \
 193                                              DNS_TRANSACTION_ATTEMPTS_MAX))