src/resolve/resolved-dns-transaction.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   This file is part of systemd.
   6
   7   Copyright 2014 Lennart Poettering
   8 ***/
   9
  10 typedef struct DnsTransaction DnsTransaction;
  11 typedef enum DnsTransactionState DnsTransactionState;
  12 typedef enum DnsTransactionSource DnsTransactionSource;
  13
  14 enum DnsTransactionState {
  15         DNS_TRANSACTION_NULL,
  16         DNS_TRANSACTION_PENDING,
  17         DNS_TRANSACTION_VALIDATING,
  18         DNS_TRANSACTION_RCODE_FAILURE,
  19         DNS_TRANSACTION_SUCCESS,
  20         DNS_TRANSACTION_NO_SERVERS,
  21         DNS_TRANSACTION_TIMEOUT,
  22         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  23         DNS_TRANSACTION_INVALID_REPLY,
  24         DNS_TRANSACTION_ERRNO,
  25         DNS_TRANSACTION_ABORTED,
  26         DNS_TRANSACTION_DNSSEC_FAILED,
  27         DNS_TRANSACTION_NO_TRUST_ANCHOR,
  28         DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
  29         DNS_TRANSACTION_NETWORK_DOWN,
  30         DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
  31         _DNS_TRANSACTION_STATE_MAX,
  32         _DNS_TRANSACTION_STATE_INVALID = -1
  33 };
  34
  35 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  36
  37 enum DnsTransactionSource {
  38         DNS_TRANSACTION_NETWORK,
  39         DNS_TRANSACTION_CACHE,
  40         DNS_TRANSACTION_ZONE,
  41         DNS_TRANSACTION_TRUST_ANCHOR,
  42         _DNS_TRANSACTION_SOURCE_MAX,
  43         _DNS_TRANSACTION_SOURCE_INVALID = -1
  44 };
  45
  46 #include "resolved-dns-answer.h"
  47 #include "resolved-dns-packet.h"
  48 #include "resolved-dns-question.h"
  49 #include "resolved-dns-scope.h"
  50 #include "resolved-dns-server.h"
  51 #include "resolved-dns-stream.h"
  52
  53 struct DnsTransaction {
  54         DnsScope *scope;
  55
  56         DnsResourceKey *key;
  57
  58         DnsTransactionState state;
  59
  60         uint16_t id;
  61
  62         bool tried_stream:1;
  63
  64         bool initial_jitter_scheduled:1;
  65         bool initial_jitter_elapsed:1;
  66
  67         bool clamp_ttl:1;
  68
  69         bool probing:1;
  70
  71         DnsPacket *sent, *received;
  72
  73         DnsAnswer *answer;
  74         int answer_rcode;
  75         DnssecResult answer_dnssec_result;
  76         DnsTransactionSource answer_source;
  77         uint32_t answer_nsec_ttl;
  78         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  79
  80         /* Indicates whether the primary answer is authenticated,
  81          * i.e. whether the RRs from answer which directly match the
  82          * question are authenticated, or, if there are none, whether
  83          * the NODATA or NXDOMAIN case is. It says nothing about
  84          * additional RRs listed in the answer, however they have
  85          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  86          * is defined different than the AD bit in DNS packets, as
  87          * that covers more than just the actual primary answer. */
  88         bool answer_authenticated;
  89
  90         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  91          * to authenticate this reply */
  92         DnsAnswer *validated_keys;
  93
  94         usec_t start_usec;
  95         usec_t next_attempt_after;
  96         sd_event_source *timeout_event_source;
  97         unsigned n_attempts;
  98
  99         unsigned n_picked_servers;
 100
 101         /* UDP connection logic, if we need it */
 102         int dns_udp_fd;
 103         sd_event_source *dns_udp_event_source;
 104
 105         /* TCP connection logic, if we need it */
 106         DnsStream *stream;
 107
 108         /* The active server */
 109         DnsServer *server;
 110
 111         /* The features of the DNS server at time of transaction start */
 112         DnsServerFeatureLevel current_feature_level;
 113
 114         /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
 115         DnsServerFeatureLevel clamp_feature_level;
 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, *notify_query_candidates_done;
 121
 122         /* Zone items this transaction is referenced by and that shall
 123          * be notified about completion. */
 124         Set *notify_zone_items, *notify_zone_items_done;
 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, *notify_transactions_done;
 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_state_to_string(DnsTransactionState p) _const_;
 155 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 156
 157 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 158 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 159
 160 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 161 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 162
 163 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 164 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 165 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 166
 167 /* mDNS probing interval, see RFC 6762 Section 8.1 */
 168 #define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
 169
 170 /* Maximum attempts to send DNS requests, across all DNS servers */
 171 #define DNS_TRANSACTION_ATTEMPTS_MAX 24
 172
 173 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 174 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 175
 176 /* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
 177 #define MDNS_TRANSACTION_ATTEMPTS_MAX 3
 178
 179 #define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
 180                                          LLMNR_TRANSACTION_ATTEMPTS_MAX : \
 181                                          (((p) == DNS_PROTOCOL_MDNS) ? \
 182                                              MDNS_TRANSACTION_ATTEMPTS_MAX : \
 183                                              DNS_TRANSACTION_ATTEMPTS_MAX))