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_ABORTED,
  40         DNS_TRANSACTION_DNSSEC_FAILED,
  41         _DNS_TRANSACTION_STATE_MAX,
  42         _DNS_TRANSACTION_STATE_INVALID = -1
  43 };
  44
  45 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
  46
  47 enum DnsTransactionSource {
  48         DNS_TRANSACTION_NETWORK,
  49         DNS_TRANSACTION_CACHE,
  50         DNS_TRANSACTION_ZONE,
  51         DNS_TRANSACTION_TRUST_ANCHOR,
  52         _DNS_TRANSACTION_SOURCE_MAX,
  53         _DNS_TRANSACTION_SOURCE_INVALID = -1
  54 };
  55
  56 #include "resolved-dns-answer.h"
  57 #include "resolved-dns-packet.h"
  58 #include "resolved-dns-question.h"
  59 #include "resolved-dns-scope.h"
  60
  61 struct DnsTransaction {
  62         DnsScope *scope;
  63
  64         DnsResourceKey *key;
  65         char *key_string;
  66
  67         DnsTransactionState state;
  68
  69         uint16_t id;
  70
  71         bool initial_jitter_scheduled:1;
  72         bool initial_jitter_elapsed:1;
  73
  74         DnsPacket *sent, *received;
  75
  76         DnsAnswer *answer;
  77         int answer_rcode;
  78         DnssecResult answer_dnssec_result;
  79         DnsTransactionSource answer_source;
  80
  81         /* Indicates whether the primary answer is authenticated,
  82          * i.e. whether the RRs from answer which directly match the
  83          * question are authenticated, or, if there are none, whether
  84          * the NODATA or NXDOMAIN case is. It says nothing about
  85          * additional RRs listed in the answer, however they have
  86          * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
  87          * is defined different than the AD bit in DNS packets, as
  88          * that covers more than just the actual primary answer. */
  89         bool answer_authenticated;
  90
  91         /* Contains DNSKEY, DS, SOA RRs we already verified and need
  92          * to authenticate this reply */
  93         DnsAnswer *validated_keys;
  94
  95         usec_t start_usec;
  96         usec_t next_attempt_after;
  97         sd_event_source *timeout_event_source;
  98         unsigned n_attempts;
  99
 100         int dns_udp_fd;
 101         sd_event_source *dns_udp_event_source;
 102
 103         /* The active server */
 104         DnsServer *server;
 105
 106         /* The features of the DNS server at time of transaction start */
 107         DnsServerFeatureLevel current_features;
 108
 109         /* TCP connection logic, if we need it */
 110         DnsStream *stream;
 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;
 116
 117         /* Zone items this transaction is referenced by and that shall
 118          * be notified about completion. */
 119         Set *notify_zone_items;
 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;
 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 };
 135
 136 int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
 137 DnsTransaction* dns_transaction_free(DnsTransaction *t);
 138
 139 void dns_transaction_gc(DnsTransaction *t);
 140 int dns_transaction_go(DnsTransaction *t);
 141
 142 void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
 143 void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
 144
 145 void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
 146 int dns_transaction_validate_dnssec(DnsTransaction *t);
 147 int dns_transaction_request_dnssec_keys(DnsTransaction *t);
 148
 149 const char *dns_transaction_key_string(DnsTransaction *t);
 150
 151 const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
 152 DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
 153
 154 const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
 155 DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
 156
 157 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
 158 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
 159
 160 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
 161 #define MDNS_JITTER_MIN_USEC   (20 * USEC_PER_MSEC)
 162 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
 163
 164 /* Maximum attempts to send DNS requests, across all DNS servers */
 165 #define DNS_TRANSACTION_ATTEMPTS_MAX 16
 166
 167 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
 168 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
 169
 170 #define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)