011696f762
Previously, if a hostanem is resolved with AF_UNSPEC specified, this would be used as indication to resolve both an AF_INET and an AF_INET6 address. With this change this logic is altered: an AF_INET address is only resolved if there's actually a routable IPv4 address on the specific interface, and similar an AF_INET6 address is only resolved if there's a routable IPv6 address. With this in place, it's ensured that the returned data is actually connectable by applications. This logic mimics glibc's resolver behaviour. Note that if the client asks explicitly for AF_INET or AF_INET6 it will get what it asked for. This also simplifies the logic how it is determined whether a specific lookup shall take place on a scope. Specifically, the checks with dns_scope_good_key() are now moved out of the transaction code and into the query code, so that we don't even create a transaction object on a specific scope if we cannot execute the resolution on it anyway.
136 lines
4.3 KiB
C
136 lines
4.3 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "sd-bus.h"
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#include "set.h"
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typedef struct DnsQueryCandidate DnsQueryCandidate;
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typedef struct DnsQuery DnsQuery;
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#include "resolved-dns-answer.h"
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#include "resolved-dns-question.h"
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#include "resolved-dns-stream.h"
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#include "resolved-dns-search-domain.h"
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struct DnsQueryCandidate {
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DnsQuery *query;
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DnsScope *scope;
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DnsSearchDomain *search_domain;
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int error_code;
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Set *transactions;
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LIST_FIELDS(DnsQueryCandidate, candidates_by_query);
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LIST_FIELDS(DnsQueryCandidate, candidates_by_scope);
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};
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struct DnsQuery {
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Manager *manager;
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/* When resolving a service, we first create a TXT+SRV query,
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* and then for the hostnames we discover auxiliary A+AAAA
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* queries. This pointer always points from the auxiliary
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* queries back to the TXT+SRV query. */
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DnsQuery *auxiliary_for;
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LIST_HEAD(DnsQuery, auxiliary_queries);
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unsigned n_auxiliary_queries;
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int auxiliary_result;
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/* The question, formatted in IDNA for use on classic DNS, and as UTF8 for use in LLMNR or mDNS. Note that even
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* on classic DNS some labels might use UTF8 encoding. Specifically, DNS-SD service names (in contrast to their
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* domain suffixes) use UTF-8 encoding even on DNS. Thus, the difference between these two fields is mostly
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* relevant only for explicit *hostname* lookups as well as the domain suffixes of service lookups. */
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DnsQuestion *question_idna;
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DnsQuestion *question_utf8;
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uint64_t flags;
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int ifindex;
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/* If true, A or AAAA RR lookups will be suppressed on links with no routable address of the matching address
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* family */
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bool suppress_unroutable_family;
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DnsTransactionState state;
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unsigned n_cname_redirects;
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LIST_HEAD(DnsQueryCandidate, candidates);
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sd_event_source *timeout_event_source;
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/* Discovered data */
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DnsAnswer *answer;
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int answer_rcode;
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DnssecResult answer_dnssec_result;
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bool answer_authenticated;
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DnsProtocol answer_protocol;
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int answer_family;
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DnsSearchDomain *answer_search_domain;
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int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
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/* Bus client information */
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sd_bus_message *request;
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int request_family;
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bool request_address_valid;
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union in_addr_union request_address;
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unsigned block_all_complete;
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char *request_address_string;
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/* Completion callback */
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void (*complete)(DnsQuery* q);
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unsigned block_ready;
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sd_bus_track *bus_track;
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LIST_FIELDS(DnsQuery, queries);
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LIST_FIELDS(DnsQuery, auxiliary_queries);
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};
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enum {
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DNS_QUERY_MATCH,
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DNS_QUERY_NOMATCH,
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DNS_QUERY_RESTARTED,
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};
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DnsQueryCandidate* dns_query_candidate_free(DnsQueryCandidate *c);
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void dns_query_candidate_notify(DnsQueryCandidate *c);
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int dns_query_new(Manager *m, DnsQuery **q, DnsQuestion *question_utf8, DnsQuestion *question_idna, int family, uint64_t flags);
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DnsQuery *dns_query_free(DnsQuery *q);
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int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for);
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int dns_query_go(DnsQuery *q);
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void dns_query_ready(DnsQuery *q);
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int dns_query_process_cname(DnsQuery *q);
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int dns_query_bus_track(DnsQuery *q, sd_bus_message *m);
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DnsQuestion* dns_query_question_for_protocol(DnsQuery *q, DnsProtocol protocol);
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const char *dns_query_string(DnsQuery *q);
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DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQuery*, dns_query_free);
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