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