de54e62b4b
This adds logic to downgrade the feature level more aggressively when we have reason to. Specifically: - When we get a response packet that lacks an OPT RR for a query that had it. If so, downgrade immediately to UDP mode, i.e. don't generate EDNS0 packets anymore. - When we get a response which we are sure should be signed, but lacks RRSIG RRs, we downgrade to EDNS0 mode, i.e. below DO mode, since DO is apparently not really supported. This should increase compatibility with servers that generate non-sensical responses if they messages with OPT RRs and suchlike, for example the situation described here: https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html This also changes the downgrade code to explain in a debug log message why a specific downgrade happened.
137 lines
4.2 KiB
C
137 lines
4.2 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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#include "in-addr-util.h"
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typedef struct DnsServer DnsServer;
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typedef enum DnsServerType {
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DNS_SERVER_SYSTEM,
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DNS_SERVER_FALLBACK,
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DNS_SERVER_LINK,
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} DnsServerType;
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typedef enum DnsServerFeatureLevel {
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DNS_SERVER_FEATURE_LEVEL_TCP,
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DNS_SERVER_FEATURE_LEVEL_UDP,
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DNS_SERVER_FEATURE_LEVEL_EDNS0,
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DNS_SERVER_FEATURE_LEVEL_DO,
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DNS_SERVER_FEATURE_LEVEL_LARGE,
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_DNS_SERVER_FEATURE_LEVEL_MAX,
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_DNS_SERVER_FEATURE_LEVEL_INVALID = -1
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} DnsServerFeatureLevel;
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#define DNS_SERVER_FEATURE_LEVEL_WORST 0
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#define DNS_SERVER_FEATURE_LEVEL_BEST (_DNS_SERVER_FEATURE_LEVEL_MAX - 1)
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const char* dns_server_feature_level_to_string(int i) _const_;
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int dns_server_feature_level_from_string(const char *s) _pure_;
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#include "resolved-link.h"
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#include "resolved-manager.h"
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struct DnsServer {
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Manager *manager;
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unsigned n_ref;
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DnsServerType type;
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Link *link;
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int family;
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union in_addr_union address;
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char *server_string;
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usec_t resend_timeout;
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usec_t max_rtt;
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DnsServerFeatureLevel verified_feature_level;
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DnsServerFeatureLevel possible_feature_level;
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size_t received_udp_packet_max;
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unsigned n_failed_udp;
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unsigned n_failed_tcp;
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bool packet_failed:1;
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bool packet_truncated:1;
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bool packet_bad_opt:1;
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bool packet_rrsig_missing:1;
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usec_t verified_usec;
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usec_t features_grace_period_usec;
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/* Used when GC'ing old DNS servers when configuration changes. */
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bool marked:1;
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/* If linked is set, then this server appears in the servers linked list */
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bool linked:1;
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LIST_FIELDS(DnsServer, servers);
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};
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int dns_server_new(
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Manager *m,
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DnsServer **ret,
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DnsServerType type,
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Link *link,
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int family,
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const union in_addr_union *address);
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DnsServer* dns_server_ref(DnsServer *s);
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DnsServer* dns_server_unref(DnsServer *s);
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void dns_server_unlink(DnsServer *s);
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void dns_server_move_back_and_unmark(DnsServer *s);
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void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t rtt, size_t size);
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void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t usec);
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void dns_server_packet_failed(DnsServer *s, DnsServerFeatureLevel level);
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void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level);
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void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level);
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void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level);
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DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s);
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int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeatureLevel level);
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const char *dns_server_string(DnsServer *server);
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bool dns_server_dnssec_supported(DnsServer *server);
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DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr);
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void dns_server_unlink_all(DnsServer *first);
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void dns_server_unlink_marked(DnsServer *first);
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void dns_server_mark_all(DnsServer *first);
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DnsServer *manager_get_first_dns_server(Manager *m, DnsServerType t);
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DnsServer *manager_set_dns_server(Manager *m, DnsServer *s);
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DnsServer *manager_get_dns_server(Manager *m);
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void manager_next_dns_server(Manager *m);
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DEFINE_TRIVIAL_CLEANUP_FUNC(DnsServer*, dns_server_unref);
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extern const struct hash_ops dns_server_hash_ops;
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