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37d7a7d984
Change the resolved.conf Cache option to a tri-state "no, no-negative, yes" values.
If a lookup returns SERVFAIL systemd-resolved will cache the result for 30s (See 201d995),
however, there are several use cases on which this condition is not acceptable (See systemd#5552 comments)
and the only workaround would be to disable cache entirely or flush it , which isn't optimal.
This change adds the 'no-negative' option when set it avoids putting in cache
negative answers but still works the same heuristics for positive answers.
Signed-off-by: Jorge Niedbalski <jnr@metaklass.org>
84 lines
2.5 KiB
C
84 lines
2.5 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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#include "conf-parser.h"
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#include "in-addr-util.h"
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#include "macro.h"
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/* 127.0.0.53 in native endian */
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#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U)
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typedef enum DnsCacheMode DnsCacheMode;
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enum DnsCacheMode {
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DNS_CACHE_MODE_NO,
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DNS_CACHE_MODE_YES,
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DNS_CACHE_MODE_NO_NEGATIVE,
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_DNS_CACHE_MODE_MAX,
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_DNS_CACHE_MODE_INVALID = 1
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};
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typedef enum ResolveSupport ResolveSupport;
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typedef enum DnssecMode DnssecMode;
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typedef enum DnsOverTlsMode DnsOverTlsMode;
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enum ResolveSupport {
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RESOLVE_SUPPORT_NO,
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RESOLVE_SUPPORT_YES,
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RESOLVE_SUPPORT_RESOLVE,
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_RESOLVE_SUPPORT_MAX,
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_RESOLVE_SUPPORT_INVALID = -1
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};
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enum DnssecMode {
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/* No DNSSEC validation is done */
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DNSSEC_NO,
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/* Validate locally, if the server knows DO, but if not,
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* don't. Don't trust the AD bit. If the server doesn't do
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* DNSSEC properly, downgrade to non-DNSSEC operation. Of
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* course, we then are vulnerable to a downgrade attack, but
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* that's life and what is configured. */
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DNSSEC_ALLOW_DOWNGRADE,
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/* Insist on DNSSEC server support, and rather fail than downgrading. */
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DNSSEC_YES,
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_DNSSEC_MODE_MAX,
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_DNSSEC_MODE_INVALID = -1
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};
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enum DnsOverTlsMode {
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/* No connection is made for DNS-over-TLS */
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DNS_OVER_TLS_NO,
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/* Try to connect using DNS-over-TLS, but if connection fails,
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* fallback to using an unencrypted connection */
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DNS_OVER_TLS_OPPORTUNISTIC,
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/* Enforce DNS-over-TLS and require valid server certificates */
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DNS_OVER_TLS_YES,
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_DNS_OVER_TLS_MODE_MAX,
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_DNS_OVER_TLS_MODE_INVALID = -1
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};
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CONFIG_PARSER_PROTOTYPE(config_parse_resolve_support);
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CONFIG_PARSER_PROTOTYPE(config_parse_dnssec_mode);
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CONFIG_PARSER_PROTOTYPE(config_parse_dns_over_tls_mode);
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CONFIG_PARSER_PROTOTYPE(config_parse_dns_cache_mode);
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const char* resolve_support_to_string(ResolveSupport p) _const_;
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ResolveSupport resolve_support_from_string(const char *s) _pure_;
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const char* dnssec_mode_to_string(DnssecMode p) _const_;
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DnssecMode dnssec_mode_from_string(const char *s) _pure_;
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const char* dns_over_tls_mode_to_string(DnsOverTlsMode p) _const_;
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DnsOverTlsMode dns_over_tls_mode_from_string(const char *s) _pure_;
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bool dns_server_address_valid(int family, const union in_addr_union *sa);
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const char* dns_cache_mode_to_string(DnsCacheMode p) _const_;
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DnsCacheMode dns_cache_mode_from_string(const char *s) _pure_;
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