1ORG.FREEDESKTOP.RESOLVE1(5)org.freedesktop.resolve1ORG.FREEDESKTOP.RESOLVE1(5)
2
6 org.freedesktop.resolve1 - The D-Bus interface of systemd-resolved
7
9 systemd-resolved.service(8) is a system service that provides hostname
10 resolution and caching using DNS, LLMNR, and mDNS. It also does DNSSEC
11 validation. This page describes the resolve semantics and the D-Bus
12 interface.
13 This page contains an API reference only. If you are looking for a
15 longer explanation how to use this API, please consult Writing Network
16 Configuration Managers[1] and Writing Resolver Clients[2].
17
19 The service exposes the following interfaces on the Manager object on
20 the bus:
21 node /org/freedesktop/resolve1 {
23 interface org.freedesktop.resolve1.Manager {
24 methods:
25 ResolveHostname(in i ifindex,
26 in s name,
27 in i family,
28 in t flags,
29 out a(iiay) addresses,
30 out s canonical,
31 out t flags);
32 ResolveAddress(in i ifindex,
33 in i family,
34 in ay address,
35 in t flags,
36 out a(is) names,
37 out t flags);
38 ResolveRecord(in i ifindex,
39 in s name,
40 in q class,
41 in q type,
42 in t flags,
43 out a(iqqay) records,
44 out t flags);
45 ResolveService(in i ifindex,
46 in s name,
47 in s type,
48 in s domain,
49 in i family,
50 in t flags,
51 out a(qqqsa(iiay)s) srv_data,
52 out aay txt_data,
53 out s canonical_name,
54 out s canonical_type,
55 out s canonical_domain,
56 out t flags);
57 GetLink(in i ifindex,
58 out o path);
59 SetLinkDNS(in i ifindex,
60 in a(iay) addresses);
61 SetLinkDNSEx(in i ifindex,
62 in a(iayqs) addresses);
63 SetLinkDomains(in i ifindex,
64 in a(sb) domains);
65 SetLinkDefaultRoute(in i ifindex,
66 in b enable);
67 SetLinkLLMNR(in i ifindex,
68 in s mode);
69 SetLinkMulticastDNS(in i ifindex,
70 in s mode);
71 SetLinkDNSOverTLS(in i ifindex,
72 in s mode);
73 SetLinkDNSSEC(in i ifindex,
74 in s mode);
75 SetLinkDNSSECNegativeTrustAnchors(in i ifindex,
76 in as names);
77 RevertLink(in i ifindex);
78 RegisterService(in s name,
79 in s name_template,
80 in s type,
81 in q service_port,
82 in q service_priority,
83 in q service_weight,
84 in aa{say} txt_datas,
85 out o service_path);
86 UnregisterService(in o service_path);
87 ResetStatistics();
88 FlushCaches();
89 ResetServerFeatures();
90 properties:
91 readonly s LLMNRHostname = '...';
92 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
93 readonly s LLMNR = '...';
94 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
95 readonly s MulticastDNS = '...';
96 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
97 readonly s DNSOverTLS = '...';
98 readonly a(iiay) DNS = [...];
99 readonly a(iiayqs) DNSEx = [...];
100 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
101 readonly a(iiay) FallbackDNS = [...];
102 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
103 readonly a(iiayqs) FallbackDNSEx = [...];
104 readonly (iiay) CurrentDNSServer = ...;
105 readonly (iiayqs) CurrentDNSServerEx = ...;
106 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
107 readonly a(isb) Domains = [...];
108 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
109 readonly (tt) TransactionStatistics = ...;
110 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
111 readonly (ttt) CacheStatistics = ...;
112 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
113 readonly s DNSSEC = '...';
114 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
115 readonly (tttt) DNSSECStatistics = ...;
116 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
117 readonly b DNSSECSupported = ...;
118 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
119 readonly as DNSSECNegativeTrustAnchors = ['...', ...];
120 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
121 readonly s DNSStubListener = '...';
122 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
123 readonly s ResolvConfMode = '...';
124 };
125 interface org.freedesktop.DBus.Peer { ... };
126 interface org.freedesktop.DBus.Introspectable { ... };
127 interface org.freedesktop.DBus.Properties { ... };
128 };
129 Methods
172 ResolveHostname() takes a hostname and resolves it to one or more IP
173 addresses. As parameters it takes the Linux network interface index to
174 execute the query on, or 0 if it may be done on any suitable interface.
175 The name parameter specifies the hostname to resolve. Note that if
176 required, IDNA conversion is applied to this name unless it is resolved
177 via LLMNR or MulticastDNS. The family parameter limits the results to a
178 specific address family. It may be AF_INET, AF_INET6 or AF_UNSPEC. If
179 AF_UNSPEC is specified (recommended), both kinds are retrieved, subject
180 to local network configuration (i.e. if no local, routable IPv6 address
181 is found, no IPv6 address is retrieved; and similarly for IPv4). A
182 64-bit flags field may be used to alter the behaviour of the resolver
183 operation (see below). The method returns an array of address records.
184 Each address record consists of the interface index the address belongs
185 to, an address family as well as a byte array with the actual IP
186 address data (which either has 4 or 16 elements, depending on the
187 address family). The returned address family will be one of AF_INET or
188 AF_INET6. For IPv6, the returned address interface index should be used
189 to initialize the .sin6_scope_id field of a struct sockaddr_in6
190 instance to permit support for resolution to link-local IP addresses.
191 The address array is followed by the canonical name of the host, which
192 may or may not be identical to the resolved hostname. Finally, a 64-bit
193 flags field is returned that is defined similarly to the flags field
194 that was passed in, but contains information about the resolved data
195 (see below). If the hostname passed in is an IPv4 or IPv6 address
196 formatted as string, it is parsed, and the result is returned. In this
197 case, no network communication is done.
198 ResolveAddress() executes the reverse operation: it takes an IP address
200 and acquires one or more hostnames for it. As parameters it takes the
201 interface index to execute the query on, or 0 if all suitable
202 interfaces are OK. The family parameter indicates the address family of
203 the IP address to resolve. It may be either AF_INET or AF_INET6. The
204 address parameter takes the raw IP address data (as either a 4 or 16
205 byte array). The flags input parameter may be used to alter the
206 resolver operation (see below). The method returns an array of name
207 records, each consisting of an interface index and a hostname. The
208 flags output field contains additional information about the resolver
209 operation (see below).
210 ResolveRecord() takes a DNS resource record (RR) type, class and name,
212 and retrieves the full resource record set (RRset), including the
213 RDATA, for it. As parameter it takes the Linux network interface index
214 to execute the query on, or 0 if it may be done on any suitable
215 interface. The name parameter specifies the RR domain name to look up
216 (no IDNA conversion is applied), followed by the 16-bit class and type
217 fields (which may be ANY). Finally, a flags field may be passed in to
218 alter behaviour of the look-up (see below). On completion, an array of
219 RR items is returned. Each array entry consists of the network
220 interface index the RR was discovered on, the type and class field of
221 the RR found, and a byte array of the raw RR discovered. The raw RR
222 data starts with the RR's domain name, in the original casing, followed
223 by the RR type, class, TTL and RDATA, in the binary format documented
224 in RFC 1035[3]. For RRs that support name compression in the payload
225 (such as MX or PTR), the compression is expanded in the returned data.
226 Note that currently, the class field has to be specified as IN or ANY.
228 Specifying a different class will return an error indicating that
229 look-ups of this kind are unsupported. Similarly, some special types
230 are not supported either (AXFR, OPT, ...). While systemd-resolved
231 parses and validates resource records of many types, it is crucial that
232 clients using this API understand that the RR data originates from the
233 network and should be thoroughly validated before use.
234 ResolveService() may be used to resolve a DNS SRV service record, as
236 well as the hostnames referenced in it, and possibly an accompanying
237 DNS-SD TXT record containing additional service metadata. The primary
238 benefit of using this method over ResolveRecord() specifying the SRV
239 type is that it will resolve the SRV and TXT RRs as well as the
240 hostnames referenced in the SRV in a single operation. As parameters it
241 takes a Linux network interface index, a service name, a service type
242 and a service domain. This method may be invoked in three different
243 modes:
244 1. To resolve a DNS-SD service, specify the service name (e.g.
246 "Lennart's Files"), the service type (e.g. "_webdav._tcp") and the
247 domain to search in (e.g. "local") as the three service
248 parameters. The service name must be in UTF-8 format, and no IDNA
249 conversion is applied to it in this mode (as mandated by the DNS-SD
250 specifications). However, if necessary, IDNA conversion is applied
251 to the domain parameter.
252 2. To resolve a plain SRV record, set the service name parameter to
254 the empty string and set the service type and domain properly.
255 (IDNA conversion is applied to the domain, if necessary.)
256 3. Alternatively, leave both the service name and type empty and
258 specify the full domain name of the SRV record (i.e. prefixed with
259 the service type) in the domain parameter. (No IDNA conversion is
260 applied in this mode.)
261 The family parameter of the ResolveService() method encodes the desired
263 family of the addresses to resolve (use AF_INET, AF_INET6, or
264 AF_UNSPEC). If this is enabled (Use the NO_ADDRESS flag to turn address
265 resolution off, see below). The flags parameter takes a couple of flags
266 that may be used to alter the resolver operation.
267 On completion, ResolveService() returns an array of SRV record
269 structures. Each items consisting of the priority, weight and port
270 fields as well as the hostname to contact, as encoded in the SRV
271 record. Immediately following is an array of the addresses of this
272 hostname, with each item consisting of the interface index, the address
273 family and the address data in a byte array. This address array is
274 followed by the canonicalized hostname. After this array of SRV record
275 structures an array of byte arrays follows that encodes the TXT RR
276 strings, in case DNS-SD look-ups are enabled. The next parameters are
277 the canonical service name, type and domain. This may or may not be
278 identical to the parameters passed in. Finally, a flags field is
279 returned that contains information about the resolver operation
280 performed.
281 The ResetStatistics() method resets the various statistics counters
283 that systemd-resolved maintains to zero. (For details, see the
284 statistics properties below.)
285 The GetLink() method takes a network interface index and returns the
287 object path to the org.freedesktop.resolve1.Link object corresponding
288 to it.
289 The SetLinkDNS() method sets the DNS servers to use on a specific
291 interface. This method (and the following ones) may be used by network
292 management software to configure per-interface DNS settings. It takes a
293 network interface index as well as an array of DNS server IP address
294 records. Each array item consists of an address family (either AF_INET
295 or AF_INET6), followed by a 4-byte or 16-byte array with the raw
296 address data. This method is a one-step shortcut for retrieving the
297 Link object for a network interface using GetLink() (see above) and
298 then invoking the SetDNS() method (see below) on it.
299 SetLinkDNSEx() is similar to SetLinkDNS(), but allows an IP port
301 (instead of the default 53) and DNS name to be specified for each DNS
302 server. The server name is used for Server Name Indication (SNI), which
303 is useful when DNS-over-TLS is used. C.f. DNS= in resolved.conf(5).
304 SetLinkDefaultRoute() specifies whether the link shall be used as the
306 default route for name queries. See the description of name routing in
307 systemd-resolved.service(8) for details.
308 The SetLinkDomains() method sets the search and routing domains to use
310 on a specific network interface for DNS look-ups. It takes a network
311 interface index and an array of domains, each with a boolean parameter
312 indicating whether the specified domain shall be used as a search
313 domain (false), or just as a routing domain (true). Search domains are
314 used for qualifying single-label names into FQDN when looking up
315 hostnames, as well as for making routing decisions on which interface
316 to send queries ending in the domain to. Routing domains are only used
317 for routing decisions and not used for single-label name qualification.
318 Pass the search domains in the order they should be used.
319 The SetLinkLLMNR() method enables or disables LLMNR support on a
321 specific network interface. It takes a network interface index as well
322 as a string that may either be empty or one of "yes", "no" or
323 "resolve". If empty, the systemd-wide default LLMNR setting is used. If
324 "yes", LLMNR is used for resolution of single-label names and the local
325 hostname is registered on all local LANs for LLMNR resolution by peers.
326 If "no", LLMNR is turned off fully on this interface. If "resolve",
327 LLMNR is only enabled for resolving names, but the local hostname is
328 not registered for other peers to use.
329 Similarly, the SetLinkMulticastDNS() method enables or disables
331 MulticastDNS support on a specific interface. It takes the same
332 parameters as SetLinkLLMNR() described above.
333 The SetLinkDNSSEC() method enables or disables DNSSEC validation on a
335 specific network interface. It takes a network interface index as well
336 as a string that may either be empty or one of "yes", "no", or
337 "allow-downgrade". When empty, the system-wide default DNSSEC setting
338 is used. If "yes", full DNSSEC validation is done for all look-ups. If
339 the selected DNS server does not support DNSSEC, look-ups will fail if
340 this mode is used. If "no", DNSSEC validation is fully disabled. If
341 "allow-downgrade", DNSSEC validation is enabled, but is turned off
342 automatically if the selected server does not support it (thus opening
343 up behaviour to downgrade attacks). Note that DNSSEC only applies to
344 traditional DNS, not to LLMNR or MulticastDNS.
345 The SetLinkDNSSECNegativeTrustAnchors() method may be used to configure
347 DNSSEC Negative Trust Anchors (NTAs) for a specific network interface.
348 It takes a network interface index and a list of domains as arguments.
349 The SetLinkDNSOverTLS() method enables or disables DNS-over-TLS. C.f.
351 DNSOverTLS= in systemd-resolved.service(8) for details.
352 Network management software integrating with systemd-resolved should
354 call SetLinkDNS() or SetLinkDNSEx(), SetLinkDefaultRoute(),
355 SetLinkDomains() and others after the interface appeared in the kernel
356 (and thus after a network interface index has been assigned), but
357 before the network interfaces is activated (IFF_UP set) so that all
358 settings take effect during the full time the network interface is up.
359 It is safe to alter settings while the interface is up, however. Use
360 RevertLink() (described below) to reset all per-interface settings.
361 The RevertLink() method may be used to revert all per-link settings
363 described above to the defaults.
364 The Flags Parameter
366 The four methods above accept and return a 64-bit flags value. In
367 most cases passing 0 is sufficient and recommended. However, the
368 following flags are defined to alter the look-up:
369 #define SD_RESOLVED_DNS (UINT64_C(1) << 0)
371 #define SD_RESOLVED_LLMNR_IPV4 (UINT64_C(1) << 1)
372 #define SD_RESOLVED_LLMNR_IPV6 (UINT64_C(1) << 2)
373 #define SD_RESOLVED_MDNS_IPV4 (UINT64_C(1) << 3)
374 #define SD_RESOLVED_MDNS_IPV6 (UINT64_C(1) << 4)
375 #define SD_RESOLVED_NO_CNAME (UINT64_C(1) << 5)
376 #define SD_RESOLVED_NO_TXT (UINT64_C(1) << 6)
377 #define SD_RESOLVED_NO_ADDRESS (UINT64_C(1) << 7)
378 #define SD_RESOLVED_NO_SEARCH (UINT64_C(1) << 8)
379 #define SD_RESOLVED_AUTHENTICATED (UINT64_C(1) << 9)
380 On input, the first five flags control the protocols to use for the
383 look-up. They refer to classic unicast DNS, LLMNR via IPv4/UDP and
384 IPv6/UDP respectively, as well as MulticastDNS via IPv4/UDP and
385 IPv6/UDP. If all of these five bits are off on input (which is
386 strongly recommended) the look-up will be done via all suitable
387 protocols for the specific look-up. Note that these flags operate
388 as filter only, but cannot force a look-up to be done via a
389 protocol. Specifically, systemd-resolved will only route look-ups
390 within the .local TLD to MulticastDNS (plus some reverse look-up
391 address domains), and single-label names to LLMNR (plus some
392 reverse address lookup domains). It will route neither of these to
393 Unicast DNS servers. Also, it will do LLMNR and Multicast DNS only
394 on interfaces suitable for multicast.
395 On output, these five flags indicate which protocol was used to
397 execute the operation, and hence where the data was found.
398 The primary use cases for these five flags are follow-up look-ups
400 based on DNS data retrieved earlier. In this case it is often a
401 good idea to limit the follow-up look-up to the protocol that was
402 used to discover the first DNS result.
403 The NO_CNAME flag controls whether CNAME/DNAME resource records
405 shall be followed during the look-up. This flag is only available
406 at input, none of the functions will return it on output. If a
407 CNAME/DNAME RR is discovered while resolving a hostname, an error
408 is returned instead. By default, when the flag is off, CNAME/DNAME
409 RRs are followed.
410 The NO_TXT and NO_ADDRESS flags only influence operation of the
412 ResolveService() method. They are only defined for input, not
413 output. If NO_TXT set, the DNS-SD TXT RR look-up is not done in the
414 same operation. If NO_ADDRESS is specified, the hostnames
415 discovered are not implicitly translated to their addresses.
416 The NO_SEARCH flag turns off the search domain logic. It is only
418 defined for input in ResolveHostname(). When specified,
419 single-label hostnames are not qualified using defined search
420 domains, if any are configured. Note that ResolveRecord() will
421 never qualify single-label domain names using search domains. Also
422 note that multi-label hostnames are never subject to search list
423 expansion.
424 The AUTHENTICATED bit is defined only in the output flags of the
426 four functions. If set, the returned data has been fully
427 authenticated. Specifically, this bit is set for all
428 DNSSEC-protected data for which a full trust chain may be
429 established to a trusted domain anchor. It is also set for locally
430 synthesized data, such as "localhost" or data from /etc/hosts.
431 Moreover, it is set for all LLMNR or mDNS RRs which originate from
432 the local host. Applications that require authenticated RR data for
433 operation should check this flag before trusting the data. Note
434 that systemd-resolved will never return invalidated data, hence
435 this flag simply allows to discern the cases where data is known to
436 be trustable, or where there is proof that the data is "rightfully"
437 unauthenticated (which includes cases where the underlying protocol
438 or server does not support authenticating data).
439 Properties
441 The LLMNR and MulticastDNS properties report whether LLMNR and
442 MulticastDNS are (globally) enabled. Each may be one of "yes", "no",
443 and "resolve". See SetLinkLLMNR() and SetLinkMulticastDNS() above.
444 LLMNRHostname contains the hostname currently exposed on the network
446 via LLMNR. It usually follows the system hostname as may be queried via
447 gethostname(3), but may differ if a conflict is detected on the
448 network.
449 DNS and DNSEx contain arrays of all DNS servers currently used by
451 systemd-resolved. DNS contains information similar to the DNS server
452 data in /run/systemd/resolve/resolv.conf. Each structure in the array
453 consists of a numeric network interface index, an address family, and a
454 byte array containing the DNS server address (either 4 bytes in length
455 for IPv4 or 16 bytes in lengths for IPv6). DNSEx is similar, but
456 additionally contains the IP port and server name (used for Server Name
457 Indication, SNI). Both arrays contain DNS servers configured
458 system-wide, including those possibly read from a foreign
459 /etc/resolv.conf or the DNS= setting in /etc/systemd/resolved.conf, as
460 well as per-interface DNS server information either retrieved from
461 systemd-networkd(8), or configured by external software via
462 SetLinkDNS() or SetLinkDNSEx() (see above). The network interface index
463 will be 0 for the system-wide configured services and non-zero for the
464 per-link servers.
465 FallbackDNS and FallbackDNSEx contain arrays of all DNS servers
467 configured as fallback servers, if any, using the same format as DNS
468 and DNSEx described above. See the description of FallbackDNS= in
469 resolved.conf(5) for the description of when those servers are used.
470 CurrentDNSServer and CurrentDNSServerEx specify the server that is
472 currently used for query resolution, in the same format as a single
473 entry in the DNS and DNSEx arrays described above.
474 Similarly, the Domains property contains an array of all search and
476 routing domains currently used by systemd-resolved. Each entry consists
477 of a network interface index (again, 0 encodes system-wide entries),
478 the actual domain name, and whether the entry is used only for routing
479 (true) or for both routing and searching (false).
480 The TransactionStatistics property contains information about the
482 number of transactions systemd-resolved has processed. It contains a
483 pair of unsigned 64-bit counters, the first containing the number of
484 currently ongoing transactions, the second the number of total
485 transactions systemd-resolved is processing or has processed. The
486 latter value may be reset using the ResetStatistics() method described
487 above. Note that the number of transactions does not directly map to
488 the number of issued resolver bus method calls. While simple look-ups
489 usually require a single transaction only, more complex look-ups might
490 result in more, for example when CNAMEs or DNSSEC are in use.
491 The CacheStatistics property contains information about the executed
493 cache operations so far. It exposes three 64-bit counters: the first
494 being the total number of current cache entries (both positive and
495 negative), the second the number of cache hits, and the third the
496 number of cache misses. The latter counters may be reset using
497 ResetStatistics() (see above).
498 The DNSSEC property specifies current status of DNSSEC validation. It
500 is one of "yes" (validation is enforced), "no" (no validation is done),
501 "allow-downgrade" (validation is done if the current DNS server
502 supports it). See the description of DNSSEC= in resolved.conf(5).
503 The DNSSECStatistics property contains information about the DNSSEC
505 validations executed so far. It contains four 64-bit counters: the
506 number of secure, insecure, bogus, and indeterminate DNSSEC validations
507 so far. The counters are increased for each validated RRset, and each
508 non-existance proof. The secure counter is increased for each operation
509 that successfully verified a signed reply, the insecure counter is
510 increased for each operation that successfully verified that an
511 unsigned reply is rightfully unsigned. The bogus counter is increased
512 for each operation where the validation did not check out and the data
513 is likely to have been tempered with. Finally the indeterminate counter
514 is increased for each operation which did not complete because the
515 necessary keys could not be acquired or the cryptographic algorithms
516 were unknown.
517 The DNSSECSupported boolean property reports whether DNSSEC is enabled
519 and the selected DNS servers support it. It combines information about
520 system-wide and per-link DNS settings (see below), and only reports
521 true if DNSSEC is enabled and supported on every interface for which
522 DNS is configured and for the system-wide settings if there are any.
523 Note that systemd-resolved assumes DNSSEC is supported by DNS servers
524 until it verifies that this is not the case. Thus, the reported value
525 may initially be true, until the first transactions are executed.
526 The DNSOverTLS boolean property reports whether DNS-over-TLS is
528 enabled.
529 The ResolvConfMode property exposes how /etc/resolv.conf is managed on
531 the host. Currently, the values "uplink", "stub", "static" (these three
532 correspond to the three different files systemd-resolved.service
533 provides), "foreign" (the file is managed by admin or another service,
534 systemd-resolved.service just consumes it), "missing" (/etc/resolv.conf
535 is missing).
536 The DNSStubListener property reports whether the stub listener on port
538 53 is enabled. Possible values are "yes" (enabled), "no" (disabled),
539 "udp" (only the UDP listener is enabled), and "tcp" (only the TCP
540 listener is enabled).
541
543 node /org/freedesktop/resolve1/link/_1 {
544 interface org.freedesktop.resolve1.Link {
545 methods:
546 SetDNS(in a(iay) addresses);
547 SetDNSEx(in a(iayqs) addresses);
548 SetDomains(in a(sb) domains);
549 SetDefaultRoute(in b enable);
550 SetLLMNR(in s mode);
551 SetMulticastDNS(in s mode);
552 SetDNSOverTLS(in s mode);
553 SetDNSSEC(in s mode);
554 SetDNSSECNegativeTrustAnchors(in as names);
555 Revert();
556 properties:
557 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
558 readonly t ScopesMask = ...;
559 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
560 readonly a(iay) DNS = [...];
561 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
562 readonly a(iayqs) DNSEx = [...];
563 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
564 readonly (iay) CurrentDNSServer = ...;
565 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
566 readonly (iayqs) CurrentDNSServerEx = ...;
567 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
568 readonly a(sb) Domains = [...];
569 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
570 readonly b DefaultRoute = ...;
571 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
572 readonly s LLMNR = '...';
573 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
574 readonly s MulticastDNS = '...';
575 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
576 readonly s DNSOverTLS = '...';
577 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
578 readonly s DNSSEC = '...';
579 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
580 readonly as DNSSECNegativeTrustAnchors = ['...', ...];
581 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
582 readonly b DNSSECSupported = ...;
583 };
584 interface org.freedesktop.DBus.Peer { ... };
585 interface org.freedesktop.DBus.Introspectable { ... };
586 interface org.freedesktop.DBus.Properties { ... };
587 };
588 For each Linux network interface a "Link" object is created which
616 exposes per-link DNS configuration and state. Use GetLink() on the
617 Manager interface to retrieve the object path for a link object given
618 the network interface index (see above).
619 Methods
621 The various methods exposed by the Link interface are equivalent to
622 their similarly named counterparts on the Manager interface. e.g.
623 SetDNS() on the Link object maps to SetLinkDNS() on the Manager object,
624 the main difference being that the later expects an interface index to
625 be specified. Invoking the methods on the Manager interface has the
626 benefit of reducing roundtrips, as it is not necessary to first request
627 the Link object path via GetLink() before invoking the methods. The
628 same relationship holds for SetDNSEx(), SetDomains(),
629 SetDefaultRoute(), SetLLMNR(), SetMulticastDNS(), SetDNSOverTLS(),
630 SetDNSSEC(), SetDNSSECNegativeTrustAnchors(), and Revert(). For further
631 details on these methods see the Manager documentation above.
632 Properties
634 ScopesMask defines which resolver scopes are currently active on this
635 interface. This 64-bit unsigned integer field is a bit mask consisting
636 of a subset of the bits of the flags parameter describe above.
637 Specifically, it may have the DNS, LLMNR and MDNS bits (the latter in
638 IPv4 and IPv6 flavours) set. Each individual bit is set when the
639 protocol applies to a specific interface and is enabled for it. It is
640 unset otherwise. Specifically, a multicast-capable interface in the
641 "UP" state with an IP address is suitable for LLMNR or MulticastDNS,
642 and any interface that is UP and has an IP address is suitable for DNS.
643 Note the relationship of the bits exposed here with the LLMNR and
644 MulticastDNS properties also exposed on the Link interface. The latter
645 expose what is *configured* to be used on the interface, the former
646 expose what is actually used on the interface, taking into account the
647 abilities of the interface.
648 DNSSECSupported exposes a boolean field that indicates whether DNSSEC
650 is currently configured and in use on the interface. Note that if
651 DNSSEC is enabled on an interface, it is assumed available until it is
652 detected that the configured server does not actually support it. Thus,
653 this property may initially report that DNSSEC is supported on an
654 interface.
655 DefaultRoute exposes a boolean field that indicates whether the
657 interface will be used as default route for name queries. See
658 SetLinkDefaultRoute() above.
659 The other properties reflect the state of the various configuration
661 settings for the link which may be set with the various methods calls
662 such as SetDNS() or SetLLMNR().
663
665 Many bus methods systemd-resolved exposes (in particular the resolver
666 methods such as ResolveHostname() on the Manager interface) may return
667 some of the following errors:
668 org.freedesktop.resolve1.NoNameServers
670 No suitable DNS servers were found to resolve a request.
671 org.freedesktop.resolve1.InvalidReply
673 A response from the selected DNS server was not understood.
674 org.freedesktop.resolve1.NoSuchRR
676 The requested name exists, but there is no resource record of the
677 requested type for it. (This is the DNS NODATA case).
678 org.freedesktop.resolve1.CNameLoop
680 The look-up failed because a CNAME or DNAME loop was detected.
681 org.freedesktop.resolve1.Aborted
683 The look-up was aborted because the selected protocol became
684 unavailable while the operation was ongoing.
685 org.freedesktop.resolve1.NoSuchService
687 A service look-up was successful, but the SRV record reported that
688 the service is not available.
689 org.freedesktop.resolve1.DnssecFailed
691 The acquired response did not pass DNSSEC validation.
692 org.freedesktop.resolve1.NoTrustAnchor
694 No chain of trust could be established for the response to a
695 configured DNSSEC trust anchor.
696 org.freedesktop.resolve1.ResourceRecordTypeUnsupported
698 The requested resource record type is not supported on the selected
699 DNS servers. This error is generated for example when an RRSIG
700 record is requested from a DNS server that does not support DNSSEC.
701 org.freedesktop.resolve1.NoSuchLink
703 No network interface with the specified network interface index
704 exists.
705 org.freedesktop.resolve1.LinkBusy
707 The requested configuration change could not be made because
708 systemd-networkd(8), already took possession of the interface and
709 supplied configuration data for it.
710 org.freedesktop.resolve1.NetworkDown
712 The requested look-up failed because the system is currently not
713 connected to any suitable network.
714 org.freedesktop.resolve1.DnsError.NXDOMAIN,
716 org.freedesktop.resolve1.DnsError.REFUSED, ...
717 The look-up failed with a DNS return code reporting a failure. The
718 error names used as suffixes here are defined in by IANA in
719 DNS RCODEs[4].
720
722 Example 1. Introspect org.freedesktop.resolve1.Manager on the bus
723 $ gdbus introspect --system \
725 --dest org.freedesktop.resolve1 \
726 --object-path /org/freedesktop/resolve1
727 Example 2. Introspect org.freedesktop.resolve1.Link on the bus
730 $ gdbus introspect --system \
732 --dest org.freedesktop.resolve1 \
733 --object-path /org/freedesktop/resolve1/link/_11
734
737 These D-Bus interfaces follow the usual interface versioning
738 guidelines[5].
739
741 1. Writing Network Configuration Managers
742 https://wiki.freedesktop.org/www/Software/systemd/writing-network-configuration-managers
743 2. Writing Resolver Clients
745 https://wiki.freedesktop.org/www/Software/systemd/writing-resolver-clients
746 3. RFC 1035
748 https://www.ietf.org/rfc/rfc1035.txt
749 4. DNS RCODEs
751 https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6
752 5. the usual interface versioning guidelines
754 http://0pointer.de/blog/projects/versioning-dbus.html
755systemd 248 ORG.FREEDESKTOP.RESOLVE1(5)