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