Systemd/src/resolve/resolved-dns-transaction.h
Lennart Poettering 79e2493138 resolved: rework how and when the number of answer RRs to cache is determined
Instead of figuring out how many RRs to cache right before we do so,
determine this at the time we install the answer RRs, so that we can
still alter this as we manipulate the answer during validation.

The primary purpose of this is to pave the way so that we can drop
unsigned RRsets from the answer and invalidate the number of RRs to
cache at the same time.
2015-12-11 14:14:27 +01:00

159 lines
5.4 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
typedef struct DnsTransaction DnsTransaction;
typedef enum DnsTransactionState DnsTransactionState;
typedef enum DnsTransactionSource DnsTransactionSource;
enum DnsTransactionState {
DNS_TRANSACTION_NULL,
DNS_TRANSACTION_PENDING,
DNS_TRANSACTION_VALIDATING,
DNS_TRANSACTION_FAILURE,
DNS_TRANSACTION_SUCCESS,
DNS_TRANSACTION_NO_SERVERS,
DNS_TRANSACTION_TIMEOUT,
DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
DNS_TRANSACTION_INVALID_REPLY,
DNS_TRANSACTION_RESOURCES,
DNS_TRANSACTION_ABORTED,
DNS_TRANSACTION_DNSSEC_FAILED,
_DNS_TRANSACTION_STATE_MAX,
_DNS_TRANSACTION_STATE_INVALID = -1
};
#define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
enum DnsTransactionSource {
DNS_TRANSACTION_NETWORK,
DNS_TRANSACTION_CACHE,
DNS_TRANSACTION_ZONE,
DNS_TRANSACTION_TRUST_ANCHOR,
_DNS_TRANSACTION_SOURCE_MAX,
_DNS_TRANSACTION_SOURCE_INVALID = -1
};
#include "resolved-dns-answer.h"
#include "resolved-dns-packet.h"
#include "resolved-dns-question.h"
#include "resolved-dns-scope.h"
struct DnsTransaction {
DnsScope *scope;
DnsResourceKey *key;
DnsTransactionState state;
DnssecResult dnssec_result;
uint16_t id;
bool initial_jitter_scheduled;
bool initial_jitter_elapsed;
DnsPacket *sent, *received;
DnsAnswer *answer;
unsigned n_answer_cacheable; /* Specifies how many RRs of the answer shall be cached, from the beginning */
int answer_rcode;
DnsTransactionSource answer_source;
bool answer_authenticated;
/* Contains DS and DNSKEY RRs we already verified and need to authenticate this reply */
DnsAnswer *validated_keys;
usec_t start_usec;
usec_t next_attempt_after;
sd_event_source *timeout_event_source;
unsigned n_attempts;
int dns_udp_fd;
sd_event_source *dns_udp_event_source;
/* The active server */
DnsServer *server;
/* The features of the DNS server at time of transaction start */
DnsServerFeatureLevel current_features;
/* TCP connection logic, if we need it */
DnsStream *stream;
/* Query candidates this transaction is referenced by and that
* shall be notified about this specific transaction
* completing. */
Set *notify_query_candidates;
/* Zone items this transaction is referenced by and that shall
* be notified about completion. */
Set *notify_zone_items;
/* Other transactions that this transactions is referenced by
* and that shall be notified about completion. This is used
* when transactions want to validate their RRsets, but need
* another DNSKEY or DS RR to do so. */
Set *notify_transactions;
/* The opposite direction: the transactions this transaction
* created in order to request DNSKEY or DS RRs. */
Set *dnssec_transactions;
unsigned block_gc;
LIST_FIELDS(DnsTransaction, transactions_by_scope);
};
int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
DnsTransaction* dns_transaction_free(DnsTransaction *t);
void dns_transaction_gc(DnsTransaction *t);
int dns_transaction_go(DnsTransaction *t);
void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
int dns_transaction_validate_dnssec(DnsTransaction *t);
int dns_transaction_request_dnssec_keys(DnsTransaction *t);
const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
/* LLMNR Jitter interval, see RFC 4795 Section 7 */
#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
/* mDNS Jitter interval, see RFC 6762 Section 5.2 */
#define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC)
#define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
/* Maximum attempts to send DNS requests, across all DNS servers */
#define DNS_TRANSACTION_ATTEMPTS_MAX 16
/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
#define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)