45ec7efb6c
This also adds client-side support for this to systemd-resolve-host. Note that the ResolveService() API can deal both with DNS-SD service (consisting of service name, type and domain), as well as classic SRV services (consisting just of a type and a domain), all exposed in the same call. This patch also reworks CNAME handling in order to reuse it between hostname, RR and service lookups. In contrast to Avahi and Bonjour, this new API will actually reolve the A/AAAA RRs the SRV RRs point to in one go (unless this is explicitly disabled). This normally comes for free, as these RRs are sent along the SRV responses anyway, hence let's make use of that. This makes the API considerably easier to use, as a single ResolveService() invocation will return all necessary data to pick a server and connect() to it. Note that this only implements the DNS-SD resolving step, it does not implement DNS-SD browsing, as that makes sense primarily on mDNS, due to its continuous nature.
78 lines
3.2 KiB
C
78 lines
3.2 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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typedef struct DnsAnswer DnsAnswer;
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typedef struct DnsAnswerItem DnsAnswerItem;
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#include "resolved-dns-rr.h"
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/* A simple array of resource records. We keep track of the
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* originating ifindex for each RR where that makes sense, so that we
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* can qualify A and AAAA RRs referring to a local link with the
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* right ifindex. */
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struct DnsAnswerItem {
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DnsResourceRecord *rr;
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int ifindex;
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};
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struct DnsAnswer {
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unsigned n_ref;
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unsigned n_rrs, n_allocated;
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DnsAnswerItem items[0];
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};
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DnsAnswer *dns_answer_new(unsigned n);
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DnsAnswer *dns_answer_ref(DnsAnswer *a);
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DnsAnswer *dns_answer_unref(DnsAnswer *a);
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int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex);
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int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl);
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int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key);
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int dns_answer_match_soa(DnsResourceKey *key, DnsResourceKey *soa);
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int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret);
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DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b);
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void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
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int dns_answer_reserve(DnsAnswer **a, unsigned n_free);
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DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
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#define DNS_ANSWER_FOREACH(kk, a) \
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for (unsigned _i = ({ \
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(kk) = ((a) && (a)->n_rrs > 0 ? (a)->items[0].rr : NULL); \
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0; \
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}); \
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(a) && ((_i) < (a)->n_rrs); \
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_i++, (kk) = (_i < (a)->n_rrs ? (a)->items[_i].rr : NULL))
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#define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) \
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for (unsigned _i = ({ \
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(kk) = ((a) && (a)->n_rrs > 0 ? (a)->items[0].rr : NULL); \
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(ifindex) = ((a) && (a)->n_rrs > 0 ? (a)->items[0].ifindex : 0); \
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0; \
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}); \
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(a) && ((_i) < (a)->n_rrs); \
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_i++, (kk) = (_i < (a)->n_rrs ? (a)->items[_i].rr : NULL), (ifindex) = (_i < (a)->n_rrs ? (a)->items[_i].ifindex : 0))
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