src/resolve/resolved-dns-transaction.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include "sd-event.h"
   5
   6 typedef struct DnsTransaction DnsTransaction;
   7 typedef enum DnsTransactionState DnsTransactionState;
   8 typedef enum DnsTransactionSource DnsTransactionSource;
   9
  10 #include "resolved-dns-answer.h"
  11 #include "resolved-dns-dnssec.h"
  12 #include "resolved-dns-packet.h"
  13 #include "resolved-dns-question.h"
  14 #include "resolved-dns-server.h"
  15
  16 enum DnsTransactionState {
  17         DNS_TRANSACTION_NULL,
  18         DNS_TRANSACTION_PENDING,
  19         DNS_TRANSACTION_VALIDATING,
  20         DNS_TRANSACTION_RCODE_FAILURE,
  21         DNS_TRANSACTION_SUCCESS,
  22         DNS_TRANSACTION_NO_SERVERS,
  23         DNS_TRANSACTION_TIMEOUT,
  24         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  25         DNS_TRANSACTION_INVALID_REPLY,
  26         DNS_TRANSACTION_ERRNO,
  27         DNS_TRANSACTION_ABORTED,
  28         DNS_TRANSACTION_DNSSEC_FAILED,
  29         DNS_TRANSACTION_NO_TRUST_ANCHOR,
  30         DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
  31         DNS_TRANSACTION_NETWORK_DOWN,
  32         DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
  33         _DNS_TRANSACTION_STATE_MAX,
  34         _DNS_TRANSACTION_STATE_INVALID = -1
  35 };
  36
  37 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  38
  39 enum DnsTransactionSource {
  40         DNS_TRANSACTION_NETWORK,
  41         DNS_TRANSACTION_CACHE,
  42         DNS_TRANSACTION_ZONE,
  43         DNS_TRANSACTION_TRUST_ANCHOR,
  44         _DNS_TRANSACTION_SOURCE_MAX,
  45         _DNS_TRANSACTION_SOURCE_INVALID = -1
  46 };
  47
  48 struct DnsTransaction {
  49         DnsScope *scope;
  50
  51         DnsResourceKey *key;
  52
  53         DnsTransactionState state;
  54
  55         uint16_t id;
  56
  57         bool tried_stream:1;
  58
  59         bool initial_jitter_scheduled:1;
  60         bool initial_jitter_elapsed:1;
  61
  62         bool clamp_ttl:1;
  63
  64         bool probing:1;
  65
  66         DnsPacket *sent, *received;
  67
  68         DnsAnswer *answer;
  69         int answer_rcode;
  70         DnssecResult answer_dnssec_result;
  71         DnsTransactionSource answer_source;
  72         uint32_t answer_nsec_ttl;
  73         int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
  74
  75         /* Indicates whether the primary answer is authenticated,
  76          * i.e. whether the RRs from answer which directly match the
  77          * question are authenticated, or, if there are none, whether
  78          * the NODATA or NXDOMAIN case is. It says nothing about
  79          * additional RRs listed in the answer, however they have
  80          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  81          * is defined different than the AD bit in DNS packets, as
  82          * that covers more than just the actual primary answer. */
  83         bool answer_authenticated;
  84
  85         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  86          * to authenticate this reply */
  87         DnsAnswer *validated_keys;
  88
  89         usec_t start_usec;
  90         usec_t next_attempt_after;
  91         sd_event_source *timeout_event_source;
  92         unsigned n_attempts;
  93
  94         unsigned n_picked_servers;
  95
  96         /* UDP connection logic, if we need it */
  97         int dns_udp_fd;
  98         sd_event_source *dns_udp_event_source;
  99
 100         /* TCP connection logic, if we need it */
 101         DnsStream *stream;
 102
 103         /* The active server */
 104         DnsServer *server;
 105
 106         /* The features of the DNS server at time of transaction start */
 107         DnsServerFeatureLevel current_feature_level;
 108
 109         /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
 110         DnsServerFeatureLevel clamp_feature_level;
 111
 112         /* Query candidates this transaction is referenced by and that
 113          * shall be notified about this specific transaction
 114          * completing. */
 115         Set *notify_query_candidates, *notify_query_candidates_done;
 116
 117         /* Zone items this transaction is referenced by and that shall
 118          * be notified about completion. */
 119         Set *notify_zone_items, *notify_zone_items_done;
 120
 121         /* Other transactions that this transactions is referenced by
 122          * and that shall be notified about completion. This is used
 123          * when transactions want to validate their RRsets, but need
 124          * another DNSKEY or DS RR to do so. */
 125         Set *notify_transactions, *notify_transactions_done;
 126
 127         /* The opposite direction: the transactions this transaction
 128          * created in order to request DNSKEY or DS RRs. */
 129         Set *dnssec_transactions;
 130
 131         unsigned block_gc;
 132
 133         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 134         LIST_FIELDS(DnsTransaction, transactions_by_stream);
 135 };
 136
 137 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 138 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 139
 140 bool dns_transaction_gc(DnsTransaction *t);
 141 int dns_transaction_go(DnsTransaction *t);
 142
 143 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 144 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 145
 146 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 147 int dns_transaction_validate_dnssec(DnsTransaction *t);
 148 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 149
 150 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 151 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 152
 153 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 154 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 155
 156 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 157 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 158
 159 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 160 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 161 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 162
 163 /* mDNS probing interval, see RFC 6762 Section 8.1 */
 164 #define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
 165
 166 /* Maximum attempts to send DNS requests, across all DNS servers */
 167 #define DNS_TRANSACTION_ATTEMPTS_MAX 24
 168
 169 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 170 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 171
 172 /* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
 173 #define MDNS_TRANSACTION_ATTEMPTS_MAX 3
 174
 175 #define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
 176                                          LLMNR_TRANSACTION_ATTEMPTS_MAX : \
 177                                          (((p) == DNS_PROTOCOL_MDNS) ? \
 178                                              MDNS_TRANSACTION_ATTEMPTS_MAX : \
 179                                              DNS_TRANSACTION_ATTEMPTS_MAX))