src/resolve/resolved-dns-transaction.h

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 #pragma once
   4
   5 /***
   6   This file is part of systemd.
   7
   8   Copyright 2014 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 ***/
  23
  24 typedef struct DnsTransaction DnsTransaction;
  25 typedef enum DnsTransactionState DnsTransactionState;
  26 typedef enum DnsTransactionSource DnsTransactionSource;
  27
  28 enum DnsTransactionState {
  29         DNS_TRANSACTION_NULL,
  30         DNS_TRANSACTION_PENDING,
  31         DNS_TRANSACTION_VALIDATING,
  32         DNS_TRANSACTION_RCODE_FAILURE,
  33         DNS_TRANSACTION_SUCCESS,
  34         DNS_TRANSACTION_NO_SERVERS,
  35         DNS_TRANSACTION_TIMEOUT,
  36         DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
  37         DNS_TRANSACTION_INVALID_REPLY,
  38         DNS_TRANSACTION_RESOURCES,
  39         DNS_TRANSACTION_CONNECTION_FAILURE,
  40         DNS_TRANSACTION_ABORTED,
  41         DNS_TRANSACTION_DNSSEC_FAILED,
  42         _DNS_TRANSACTION_STATE_MAX,
  43         _DNS_TRANSACTION_STATE_INVALID = -1
  44 };
  45
  46 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  47
  48 enum DnsTransactionSource {
  49         DNS_TRANSACTION_NETWORK,
  50         DNS_TRANSACTION_CACHE,
  51         DNS_TRANSACTION_ZONE,
  52         DNS_TRANSACTION_TRUST_ANCHOR,
  53         _DNS_TRANSACTION_SOURCE_MAX,
  54         _DNS_TRANSACTION_SOURCE_INVALID = -1
  55 };
  56
  57 #include "resolved-dns-answer.h"
  58 #include "resolved-dns-packet.h"
  59 #include "resolved-dns-question.h"
  60 #include "resolved-dns-scope.h"
  61
  62 struct DnsTransaction {
  63         DnsScope *scope;
  64
  65         DnsResourceKey *key;
  66         char *key_string;
  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         DnsPacket *sent, *received;
  78
  79         DnsAnswer *answer;
  80         int answer_rcode;
  81         DnssecResult answer_dnssec_result;
  82         DnsTransactionSource answer_source;
  83
  84         /* Indicates whether the primary answer is authenticated,
  85          * i.e. whether the RRs from answer which directly match the
  86          * question are authenticated, or, if there are none, whether
  87          * the NODATA or NXDOMAIN case is. It says nothing about
  88          * additional RRs listed in the answer, however they have
  89          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  90          * is defined different than the AD bit in DNS packets, as
  91          * that covers more than just the actual primary answer. */
  92         bool answer_authenticated;
  93
  94         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  95          * to authenticate this reply */
  96         DnsAnswer *validated_keys;
  97
  98         usec_t start_usec;
  99         usec_t next_attempt_after;
 100         sd_event_source *timeout_event_source;
 101         unsigned n_attempts;
 102
 103         /* UDP connection logic, if we need it */
 104         int dns_udp_fd;
 105         sd_event_source *dns_udp_event_source;
 106
 107         /* TCP connection logic, if we need it */
 108         DnsStream *stream;
 109
 110         /* The active server */
 111         DnsServer *server;
 112
 113         /* The features of the DNS server at time of transaction start */
 114         DnsServerFeatureLevel current_features;
 115
 116         /* Query candidates this transaction is referenced by and that
 117          * shall be notified about this specific transaction
 118          * completing. */
 119         Set *notify_query_candidates;
 120
 121         /* Zone items this transaction is referenced by and that shall
 122          * be notified about completion. */
 123         Set *notify_zone_items;
 124
 125         /* Other transactions that this transactions is referenced by
 126          * and that shall be notified about completion. This is used
 127          * when transactions want to validate their RRsets, but need
 128          * another DNSKEY or DS RR to do so. */
 129         Set *notify_transactions;
 130
 131         /* The opposite direction: the transactions this transaction
 132          * created in order to request DNSKEY or DS RRs. */
 133         Set *dnssec_transactions;
 134
 135         unsigned block_gc;
 136
 137         LIST_FIELDS(DnsTransaction, transactions_by_scope);
 138 };
 139
 140 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 141 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 142
 143 void dns_transaction_gc(DnsTransaction *t);
 144 int dns_transaction_go(DnsTransaction *t);
 145
 146 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 147 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 148
 149 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 150 int dns_transaction_validate_dnssec(DnsTransaction *t);
 151 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 152
 153 const char *dns_transaction_key_string(DnsTransaction *t);
 154
 155 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 156 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 157
 158 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 159 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 160
 161 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 162 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 163
 164 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 165 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 166 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 167
 168 /* Maximum attempts to send DNS requests, across all DNS servers */
 169 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 170
 171 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 172 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 173
 174 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)