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         bool clamp_ttl:1;
  78
  79         DnsPacket *sent, *received;
  80
  81         DnsAnswer *answer;
  82         int answer_rcode;
  83         DnssecResult answer_dnssec_result;
  84         DnsTransactionSource answer_source;
  85         uint32_t answer_nsec_ttl;
  86         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  87
  88         /* Indicates whether the primary answer is authenticated,
  89          * i.e. whether the RRs from answer which directly match the
  90          * question are authenticated, or, if there are none, whether
  91          * the NODATA or NXDOMAIN case is. It says nothing about
  92          * additional RRs listed in the answer, however they have
  93          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  94          * is defined different than the AD bit in DNS packets, as
  95          * that covers more than just the actual primary answer. */
  96         bool answer_authenticated;
  97
  98         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  99          * to authenticate this reply */
 100         DnsAnswer *validated_keys;
 101
 102         usec_t start_usec;
 103         usec_t next_attempt_after;
 104         sd_event_source *timeout_event_source;
 105         unsigned n_attempts;
 106
 107         /* UDP connection logic, if we need it */
 108         int dns_udp_fd;
 109         sd_event_source *dns_udp_event_source;
 110
 111         /* TCP connection logic, if we need it */
 112         DnsStream *stream;
 113
 114         /* The active server */
 115         DnsServer *server;
 116
 117         /* The features of the DNS server at time of transaction start */
 118         DnsServerFeatureLevel current_feature_level;
 119
 120         /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
 121         DnsServerFeatureLevel clamp_feature_level;
 122
 123         /* Query candidates this transaction is referenced by and that
 124          * shall be notified about this specific transaction
 125          * completing. */
 126         Set *notify_query_candidates, *notify_query_candidates_done;
 127
 128         /* Zone items this transaction is referenced by and that shall
 129          * be notified about completion. */
 130         Set *notify_zone_items, *notify_zone_items_done;
 131
 132         /* Other transactions that this transactions is referenced by
 133          * and that shall be notified about completion. This is used
 134          * when transactions want to validate their RRsets, but need
 135          * another DNSKEY or DS RR to do so. */
 136         Set *notify_transactions, *notify_transactions_done;
 137
 138         /* The opposite direction: the transactions this transaction
 139          * created in order to request DNSKEY or DS RRs. */
 140         Set *dnssec_transactions;
 141
 142         unsigned block_gc;
 143
 144         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 145 };
 146
 147 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 148 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 149
 150 bool dns_transaction_gc(DnsTransaction *t);
 151 int dns_transaction_go(DnsTransaction *t);
 152
 153 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 154 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 155
 156 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 157 int dns_transaction_validate_dnssec(DnsTransaction *t);
 158 int dns_transaction_request_dnssec_keys(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)