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diff --git a/man/org.freedesktop.resolve1.xml b/man/org.freedesktop.resolve1.xml new file mode 100644 index 0000000..54f0a18 --- /dev/null +++ b/man/org.freedesktop.resolve1.xml @@ -0,0 +1,895 @@ +<?xml version="1.0"?> +<!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ +<!ENTITY % entities SYSTEM "custom-entities.ent" > +%entities; +]> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="org.freedesktop.resolve1" conditional='ENABLE_RESOLVE' + xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>org.freedesktop.resolve1</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>org.freedesktop.resolve1</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>org.freedesktop.resolve1</refname> + <refpurpose>The D-Bus interface of systemd-resolved</refpurpose> + </refnamediv> + + <refsect1> + <title>Introduction</title> + + <para> + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + is a system service that provides hostname resolution and caching using DNS, LLMNR, and mDNS. It also + does DNSSEC validation. This page describes the resolve semantics and the D-Bus interface.</para> + + <para>This page contains an API reference only. If you are looking for a longer explanation how to use + this API, please consult + <ulink url="https://wiki.freedesktop.org/www/Software/systemd/writing-network-configuration-managers"> + Writing Network Configuration Managers</ulink> and + <ulink url="https://wiki.freedesktop.org/www/Software/systemd/writing-resolver-clients">Writing Resolver + Clients</ulink>. + </para> + </refsect1> + + <refsect1> + <title>The Manager Object</title> + + <para>The service exposes the following interfaces on the Manager object on the bus:</para> + + <programlisting executable="systemd-resolved" node="/org/freedesktop/resolve1" interface="org.freedesktop.resolve1.Manager"> +node /org/freedesktop/resolve1 { + interface org.freedesktop.resolve1.Manager { + methods: + ResolveHostname(in i ifindex, + in s name, + in i family, + in t flags, + out a(iiay) addresses, + out s canonical, + out t flags); + ResolveAddress(in i ifindex, + in i family, + in ay address, + in t flags, + out a(is) names, + out t flags); + ResolveRecord(in i ifindex, + in s name, + in q class, + in q type, + in t flags, + out a(iqqay) records, + out t flags); + ResolveService(in i ifindex, + in s name, + in s type, + in s domain, + in i family, + in t flags, + out a(qqqsa(iiay)s) srv_data, + out aay txt_data, + out s canonical_name, + out s canonical_type, + out s canonical_domain, + out t flags); + GetLink(in i ifindex, + out o path); + SetLinkDNS(in i ifindex, + in a(iay) addresses); + SetLinkDNSEx(in i ifindex, + in a(iayqs) addresses); + SetLinkDomains(in i ifindex, + in a(sb) domains); + SetLinkDefaultRoute(in i ifindex, + in b enable); + SetLinkLLMNR(in i ifindex, + in s mode); + SetLinkMulticastDNS(in i ifindex, + in s mode); + SetLinkDNSOverTLS(in i ifindex, + in s mode); + SetLinkDNSSEC(in i ifindex, + in s mode); + SetLinkDNSSECNegativeTrustAnchors(in i ifindex, + in as names); + RevertLink(in i ifindex); + RegisterService(in s name, + in s name_template, + in s type, + in q service_port, + in q service_priority, + in q service_weight, + in aa{say} txt_datas, + out o service_path); + UnregisterService(in o service_path); + ResetStatistics(); + FlushCaches(); + ResetServerFeatures(); + properties: + readonly s LLMNRHostname = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s LLMNR = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s MulticastDNS = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s DNSOverTLS = '...'; + readonly a(iiay) DNS = [...]; + readonly a(iiayqs) DNSEx = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("const") + readonly a(iiay) FallbackDNS = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("const") + readonly a(iiayqs) FallbackDNSEx = [...]; + readonly (iiay) CurrentDNSServer = ...; + readonly (iiayqs) CurrentDNSServerEx = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly a(isb) Domains = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly (tt) TransactionStatistics = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly (ttt) CacheStatistics = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s DNSSEC = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly (tttt) DNSSECStatistics = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly b DNSSECSupported = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly as DNSSECNegativeTrustAnchors = ['...', ...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s DNSStubListener = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s ResolvConfMode = '...'; + }; + interface org.freedesktop.DBus.Peer { ... }; + interface org.freedesktop.DBus.Introspectable { ... }; + interface org.freedesktop.DBus.Properties { ... }; +}; + </programlisting> + + <!--method RegisterService is not documented!--> + + <!--method UnregisterService is not documented!--> + + <!--method FlushCaches is not documented!--> + + <!--method ResetServerFeatures is not documented!--> + + <!--property DNSSECNegativeTrustAnchors is not documented!--> + + <!--Autogenerated cross-references for systemd.directives, do not edit--> + + <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Manager"/> + + <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Manager"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResolveHostname()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResolveAddress()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResolveRecord()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResolveService()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="GetLink()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSEx()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDomains()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDefaultRoute()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkLLMNR()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkMulticastDNS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSOverTLS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSSEC()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSSECNegativeTrustAnchors()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="RevertLink()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="RegisterService()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="UnregisterService()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResetStatistics()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="FlushCaches()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="ResetServerFeatures()"/> + + <variablelist class="dbus-property" generated="True" extra-ref="LLMNRHostname"/> + + <variablelist class="dbus-property" generated="True" extra-ref="LLMNR"/> + + <variablelist class="dbus-property" generated="True" extra-ref="MulticastDNS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSOverTLS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSEx"/> + + <variablelist class="dbus-property" generated="True" extra-ref="FallbackDNS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="FallbackDNSEx"/> + + <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServer"/> + + <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServerEx"/> + + <variablelist class="dbus-property" generated="True" extra-ref="Domains"/> + + <variablelist class="dbus-property" generated="True" extra-ref="TransactionStatistics"/> + + <variablelist class="dbus-property" generated="True" extra-ref="CacheStatistics"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSEC"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSECStatistics"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSECSupported"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSECNegativeTrustAnchors"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSStubListener"/> + + <variablelist class="dbus-property" generated="True" extra-ref="ResolvConfMode"/> + + <!--End of Autogenerated section--> + + <refsect2> + <title>Methods</title> + + <para><function>ResolveHostname()</function> takes a hostname and resolves it to one or more IP + addresses. As parameters it takes the Linux network interface index to execute the query on, or 0 if + it may be done on any suitable interface. The <varname>name</varname> parameter specifies the hostname + to resolve. Note that if required, IDNA conversion is applied to this name unless it is resolved via + LLMNR or MulticastDNS. The <varname>family</varname> parameter limits the results to a specific address + family. It may be <constant>AF_INET</constant>, <constant>AF_INET6</constant> or + <constant>AF_UNSPEC</constant>. If <constant>AF_UNSPEC</constant> is specified (recommended), both + kinds are retrieved, subject to local network configuration (i.e. if no local, routable IPv6 address is + found, no IPv6 address is retrieved; and similarly for IPv4). A 64-bit <varname>flags</varname> field + may be used to alter the behaviour of the resolver operation (see below). The method returns an array + of address records. Each address record consists of the interface index the address belongs to, an + address family as well as a byte array with the actual IP address data (which either has 4 or 16 + elements, depending on the address family). The returned address family will be one of + <constant>AF_INET</constant> or <constant>AF_INET6</constant>. For IPv6, the returned address interface + index should be used to initialize the .sin6_scope_id field of a + <structname>struct sockaddr_in6</structname> instance to permit support for resolution to link-local IP + addresses. The address array is followed by the canonical name of the host, which may or may not be + identical to the resolved hostname. Finally, a 64-bit <varname>flags</varname> field is returned that + is defined similarly to the <varname>flags</varname> field that was passed in, but contains information + about the resolved data (see below). If the hostname passed in is an IPv4 or IPv6 address formatted as + string, it is parsed, and the result is returned. In this case, no network communication is + done.</para> + + <para><function>ResolveAddress()</function> executes the reverse operation: it takes an IP address and + acquires one or more hostnames for it. As parameters it takes the interface index to execute the query + on, or <constant>0</constant> if all suitable interfaces are OK. The <varname>family</varname> + parameter indicates the address family of the IP address to resolve. It may be either + <constant>AF_INET</constant> or <constant>AF_INET6</constant>. The <varname>address</varname> parameter + takes the raw IP address data (as either a 4 or 16 byte array). The <varname>flags</varname> input + parameter may be used to alter the resolver operation (see below). The method returns an array of name + records, each consisting of an interface index and a hostname. The <varname>flags</varname> output + field contains additional information about the resolver operation (see below).</para> + + <para><function>ResolveRecord()</function> takes a DNS resource record (RR) type, class and name, and + retrieves the full resource record set (RRset), including the RDATA, for it. As parameter it takes the + Linux network interface index to execute the query on, or <constant>0</constant> if it may be done on + any suitable interface. The <varname>name</varname> parameter specifies the RR domain name to look up + (no IDNA conversion is applied), followed by the 16-bit class and type fields (which may be + ANY). Finally, a <varname>flags</varname> field may be passed in to alter behaviour of the look-up (see + below). On completion, an array of RR items is returned. Each array entry consists of the network interface + index the RR was discovered on, the type and class field of the RR found, and a byte array of the raw + RR discovered. The raw RR data starts with the RR's domain name, in the original casing, followed + by the RR type, class, TTL and RDATA, in the binary format documented in + <ulink url="https://www.ietf.org/rfc/rfc1035.txt">RFC 1035</ulink>. For RRs that support name + compression in the payload (such as MX or PTR), the compression is expanded in the returned + data.</para> + + <para>Note that currently, the class field has to be specified as IN or ANY. Specifying a different + class will return an error indicating that look-ups of this kind are unsupported. Similarly, some + special types are not supported either (AXFR, OPT, …). While <filename>systemd-resolved</filename> parses and validates resource + records of many types, it is crucial that clients using this API understand that the RR data originates + from the network and should be thoroughly validated before use.</para> + + <para><function>ResolveService()</function> may be used to resolve a DNS + <constant class="dns">SRV</constant> service record, as well as the hostnames referenced in it, and + possibly an accompanying DNS-SD <constant class="dns">TXT</constant> record containing additional + service metadata. The primary benefit of using this method over <function>ResolveRecord()</function> + specifying the <constant class="dns">SRV</constant> type is that it will resolve the + <constant class="dns">SRV</constant> and <constant class="dns">TXT</constant> RRs as well as the + hostnames referenced in the SRV in a single operation. As parameters it takes a Linux network interface + index, a service name, a service type and a service domain. This method may be invoked in three + different modes:</para> + + <orderedlist> + <listitem><para>To resolve a DNS-SD service, specify the service name (e.g. <literal>Lennart's + Files</literal>), the service type (e.g. <literal>_webdav._tcp</literal>) and the domain to search in + (e.g. <literal>local</literal>) as the three service parameters. The service name must be in UTF-8 + format, and no IDNA conversion is applied to it in this mode (as mandated by the DNS-SD + specifications). However, if necessary, IDNA conversion is applied to the domain parameter.</para> + </listitem> + + <listitem><para>To resolve a plain <constant class="dns">SRV</constant> record, set the service name + parameter to the empty string and set the service type and domain properly. (IDNA conversion is + applied to the domain, if necessary.)</para></listitem> + + <listitem><para>Alternatively, leave both the service name and type empty and specify the full domain + name of the <constant class="dns">SRV</constant> record (i.e. prefixed with the service type) in the + domain parameter. (No IDNA conversion is applied in this mode.)</para></listitem> + </orderedlist> + + <para>The <varname>family</varname> parameter of the <function>ResolveService()</function> method encodes + the desired family of the addresses to resolve (use <constant>AF_INET</constant>, + <constant>AF_INET6</constant>, or <constant>AF_UNSPEC</constant>). If this is enabled (Use the + <constant>NO_ADDRESS</constant> flag to turn address resolution off, see below). The + <varname>flags</varname> parameter takes a couple of flags that may be used to alter the resolver + operation.</para> + + <para>On completion, <function>ResolveService()</function> returns an array of + <constant class="dns">SRV</constant> record structures. Each items consisting of the priority, weight and port + fields as well as the hostname to contact, as encoded in the <constant class="dns">SRV</constant> + record. Immediately following is an array of the addresses of this hostname, with each item consisting + of the interface index, the address family and the address data in a byte array. This address array is + followed by the canonicalized hostname. After this array of <constant class="dns">SRV</constant> record + structures an array of byte arrays follows that encodes the TXT RR strings, in case DNS-SD look-ups are + enabled. The next parameters are the canonical service name, type and domain. This may or may not be + identical to the parameters passed in. Finally, a <varname>flags</varname> field is returned that + contains information about the resolver operation performed.</para> + + <para>The <function>ResetStatistics()</function> method resets the various statistics counters that + <filename>systemd-resolved</filename> maintains to zero. (For details, see the statistics properties below.)</para> + + <para>The <function>GetLink()</function> method takes a network interface index and returns the object + path to the <interfacename>org.freedesktop.resolve1.Link</interfacename> object corresponding to it. + </para> + + <para>The <function>SetLinkDNS()</function> method sets the DNS servers to use on a specific + interface. This method (and the following ones) may be used by network management software to configure + per-interface DNS settings. It takes a network interface index as well as an array of DNS server IP + address records. Each array item consists of an address family (either <constant>AF_INET</constant> or + <constant>AF_INET6</constant>), followed by a 4-byte or 16-byte array with the raw address data. This + method is a one-step shortcut for retrieving the Link object for a network interface using + <function>GetLink()</function> (see above) and then invoking the <function>SetDNS()</function> method + (see below) on it.</para> + + <para><function>SetLinkDNSEx()</function> is similar to <function>SetLinkDNS()</function>, but allows + an IP port (instead of the default 53) and DNS name to be specified for each DNS server. The server + name is used for Server Name Indication (SNI), which is useful when DNS-over-TLS is + used. C.f. <varname>DNS=</varname> in + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + + <para><function>SetLinkDefaultRoute()</function> specifies whether the link shall be used as the + default route for name queries. See the description of name routing in + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for details.</para> + + <para>The <function>SetLinkDomains()</function> method sets the search and routing domains to use on a + specific network interface for DNS look-ups. It takes a network interface index and an array of domains, + each with a boolean parameter indicating whether the specified domain shall be used as a search domain + (false), or just as a routing domain (true). Search domains are used for qualifying single-label names into + FQDN when looking up hostnames, as well as for making routing decisions on which interface to send + queries ending in the domain to. Routing domains are only used for routing decisions and not used for single-label + name qualification. Pass the search domains in the order they should be used.</para> + + <para>The <function>SetLinkLLMNR()</function> method enables or disables LLMNR support on a specific + network interface. It takes a network interface index as well as a string that may either be empty or one of + <literal>yes</literal>, <literal>no</literal> or <literal>resolve</literal>. If empty, the systemd-wide + default LLMNR setting is used. If <literal>yes</literal>, LLMNR is used for resolution of single-label + names and the local hostname is registered on all local LANs for LLMNR resolution by peers. If + <literal>no</literal>, LLMNR is turned off fully on this interface. If <literal>resolve</literal>, LLMNR + is only enabled for resolving names, but the local hostname is not registered for other peers to + use.</para> + + <para>Similarly, the <function>SetLinkMulticastDNS()</function> method enables or disables MulticastDNS + support on a specific interface. It takes the same parameters as <function>SetLinkLLMNR()</function> + described above.</para> + + <para>The <function>SetLinkDNSSEC()</function> method enables or disables DNSSEC validation on a + specific network interface. It takes a network interface index as well as a string that may either be + empty or one of <literal>yes</literal>, <literal>no</literal>, or <literal>allow-downgrade</literal>. When + empty, the system-wide default DNSSEC setting is used. If <literal>yes</literal>, full DNSSEC validation + is done for all look-ups. If the selected DNS server does not support DNSSEC, look-ups will fail if this + mode is used. If <literal>no</literal>, DNSSEC validation is fully disabled. If + <literal>allow-downgrade</literal>, DNSSEC validation is enabled, but is turned off automatically if the + selected server does not support it (thus opening up behaviour to downgrade attacks). Note that DNSSEC + only applies to traditional DNS, not to LLMNR or MulticastDNS.</para> + + <para>The <function>SetLinkDNSSECNegativeTrustAnchors()</function> method may be used to configure DNSSEC + Negative Trust Anchors (NTAs) for a specific network interface. It takes a network interface index and a + list of domains as arguments.</para> + + <para>The <function>SetLinkDNSOverTLS()</function> method enables or disables DNS-over-TLS. + C.f. <varname>DNSOverTLS=</varname> in + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for details.</para> + + <para>Network management software integrating with <filename>systemd-resolved</filename> should call + <function>SetLinkDNS()</function> or <function>SetLinkDNSEx()</function>, + <function>SetLinkDefaultRoute()</function>, <function>SetLinkDomains()</function> and others after the + interface appeared in the kernel (and thus after a network interface index has been assigned), but + before the network interfaces is activated (<constant>IFF_UP</constant> set) so that all settings take + effect during the full time the network interface is up. It is safe to alter settings while the + interface is up, however. Use <function>RevertLink()</function> (described below) to reset all + per-interface settings.</para> + + <para>The <function>RevertLink()</function> method may be used to revert all per-link settings + described above to the defaults.</para> + + <refsect3> + <title>The Flags Parameter</title> + + <para>The four methods above accept and return a 64-bit flags value. In most cases passing 0 is sufficient + and recommended. However, the following flags are defined to alter the look-up:</para> + + <programlisting> +#define SD_RESOLVED_DNS (UINT64_C(1) << 0) +#define SD_RESOLVED_LLMNR_IPV4 (UINT64_C(1) << 1) +#define SD_RESOLVED_LLMNR_IPV6 (UINT64_C(1) << 2) +#define SD_RESOLVED_MDNS_IPV4 (UINT64_C(1) << 3) +#define SD_RESOLVED_MDNS_IPV6 (UINT64_C(1) << 4) +#define SD_RESOLVED_NO_CNAME (UINT64_C(1) << 5) +#define SD_RESOLVED_NO_TXT (UINT64_C(1) << 6) +#define SD_RESOLVED_NO_ADDRESS (UINT64_C(1) << 7) +#define SD_RESOLVED_NO_SEARCH (UINT64_C(1) << 8) +#define SD_RESOLVED_AUTHENTICATED (UINT64_C(1) << 9) +#define SD_RESOLVED_NO_VALIDATE (UINT64_C(1) << 10) +#define SD_RESOLVED_NO_SYNTHESIZE (UINT64_C(1) << 11) +#define SD_RESOLVED_NO_CACHE (UINT64_C(1) << 12) +#define SD_RESOLVED_NO_ZONE (UINT64_C(1) << 13) +#define SD_RESOLVED_NO_TRUST_ANCHOR (UINT64_C(1) << 14) +#define SD_RESOLVED_NO_NETWORK (UINT64_C(1) << 15) +#define SD_RESOLVED_REQUIRE_PRIMARY (UINT64_C(1) << 16) +#define SD_RESOLVED_CLAMP_TTL (UINT64_C(1) << 17) +#define SD_RESOLVED_CONFIDENTIAL (UINT64_C(1) << 18) +#define SD_RESOLVED_SYNTHETIC (UINT64_C(1) << 19) +#define SD_RESOLVED_FROM_CACHE (UINT64_C(1) << 20) +#define SD_RESOLVED_FROM_ZONE (UINT64_C(1) << 21) +#define SD_RESOLVED_FROM_TRUST_ANCHOR (UINT64_C(1) << 22) +#define SD_RESOLVED_FROM_NETWORK (UINT64_C(1) << 23) + </programlisting> + + <para>On input, the first five flags control the protocols to use for the look-up. They refer to + classic unicast DNS, LLMNR via IPv4/UDP and IPv6/UDP respectively, as well as MulticastDNS via + IPv4/UDP and IPv6/UDP. If all of these five bits are off on input (which is strongly recommended) the + look-up will be done via all suitable protocols for the specific look-up. Note that these flags + operate as filter only, but cannot force a look-up to be done via a protocol. Specifically, + <filename>systemd-resolved</filename> will only route look-ups within the .local TLD to MulticastDNS + (plus some reverse look-up address domains), and single-label names to LLMNR (plus some reverse + address lookup domains). It will route neither of these to Unicast DNS servers. Also, it will do + LLMNR and Multicast DNS only on interfaces suitable for multicast.</para> + + <para>On output, these five flags indicate which protocol was used to execute the operation, and hence + where the data was found.</para> + + <para>The primary use cases for these five flags are follow-up look-ups based on DNS data retrieved + earlier. In this case it is often a good idea to limit the follow-up look-up to the protocol that was + used to discover the first DNS result.</para> + + <para>The NO_CNAME flag controls whether CNAME/DNAME resource records shall be followed during the + look-up. This flag is only available at input, none of the functions will return it on output. If a + CNAME/DNAME RR is discovered while resolving a hostname, an error is returned instead. By default, + when the flag is off, CNAME/DNAME RRs are followed.</para> + + <para>The NO_TXT and NO_ADDRESS flags only influence operation of the + <function>ResolveService()</function> method. They are only defined for input, not output. If NO_TXT + is set, the DNS-SD TXT RR look-up is not done in the same operation. If NO_ADDRESS is set, the + discovered hostnames are not implicitly translated to their addresses.</para> + + <para>The NO_SEARCH flag turns off the search domain logic. It is only defined for input in + <function>ResolveHostname()</function>. When specified, single-label hostnames are not qualified + using defined search domains, if any are configured. Note that <function>ResolveRecord()</function> + will never qualify single-label domain names using search domains. Also note that + multi-label hostnames are never subject to search list expansion.</para> + + <para>The AUTHENTICATED bit is defined only in the output flags of the four functions. If set, the + returned data has been fully authenticated. Specifically, this bit is set for all DNSSEC-protected + data for which a full trust chain may be established to a trusted domain anchor. It is also set for + locally synthesized data, such as <literal>localhost</literal> or data from + <filename>/etc/hosts</filename>. Moreover, it is set for all LLMNR or mDNS RRs which originate from + the local host. Applications that require authenticated RR data for operation should check this flag + before trusting the data. Note that <filename>systemd-resolved</filename> will never return + invalidated data, hence this flag simply allows one to discern the cases where data is known to be + trusted, or where there is proof that the data is "rightfully" unauthenticated (which includes cases + where the underlying protocol or server does not support authenticating data).</para> + + <para>NO_VALIDATE can be set to disable validation via DNSSEC even if it would normally be used. + </para> + + <para>The next four flags allow disabling certain sources during resolution. NO_SYNTHESIZE disables + synthetic records, e.g. the local host name, see section SYNTHETIC RECORDS in + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for more information. NO_CACHE disables the use of the cache of previously resolved records. NO_ZONE + disables answers using locally registered public LLMNR/mDNS resource records. NO_TRUST_ANCHOR + disables answers using locally configured trust anchors. NO_NETWORK requires all answers to be + provided without using the network, i.e. either from local sources or the cache.</para> + + <para>With REQUIRE_PRIMARY the request must be answered from a "primary" answer, i.e. not from + resource records acquired as a side-effect of a previous transaction.</para> + + <para>With CLAMP_TTL, if reply is answered from cache, the TTLs will be adjusted by age of cache + entry.</para> + + <para>The next six bits flags are used in output and provide information about the source of the answer. + CONFIDENTIAL means the query was resolved via encrypted channels or never left this system. + FROM_SYNTHETIC means the query was (at least partially) synthesized. + FROM_CACHE means the query was answered (at least partially) using the cache. + FROM_ZONE means the query was answered (at least partially) using LLMNR/mDNS. + FROM_TRUST_ANCHOR means the query was answered (at least partially) using local trust anchors. + FROM_NETWORK means the query was answered (at least partially) using the network. + </para> + </refsect3> + </refsect2> + + <refsect2> + <title>Properties</title> + + <para>The <varname>LLMNR</varname> and <varname>MulticastDNS</varname> properties report whether LLMNR + and MulticastDNS are (globally) enabled. Each may be one of <literal>yes</literal>, + <literal>no</literal>, and <literal>resolve</literal>. See <function>SetLinkLLMNR()</function> + and <function>SetLinkMulticastDNS()</function> above.</para> + + <para><varname>LLMNRHostname</varname> contains the hostname currently exposed on the network via + LLMNR. It usually follows the system hostname as may be queried via + <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + but may differ if a conflict is detected on the network.</para> + + <para><varname>DNS</varname> and <varname>DNSEx</varname> contain arrays of all DNS servers currently + used by <filename>systemd-resolved</filename>. <varname>DNS</varname> contains information similar to + the DNS server data in <filename>/run/systemd/resolve/resolv.conf</filename>. Each structure in the + array consists of a numeric network interface index, an address family, and a byte array containing the + DNS server address (either 4 bytes in length for IPv4 or 16 bytes in lengths for IPv6). + <varname>DNSEx</varname> is similar, but additionally contains the IP port and server name (used for + Server Name Indication, SNI). Both arrays contain DNS servers configured system-wide, including those + possibly read from a foreign <filename>/etc/resolv.conf</filename> or the <varname>DNS=</varname> + setting in <filename>/etc/systemd/resolved.conf</filename>, as well as per-interface DNS server + information either retrieved from + <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + or configured by external software via <function>SetLinkDNS()</function> or + <function>SetLinkDNSEx()</function> (see above). The network interface index will be 0 for the + system-wide configured services and non-zero for the per-link servers.</para> + + <para><varname>FallbackDNS</varname> and <varname>FallbackDNSEx</varname> contain arrays of all DNS + servers configured as fallback servers, if any, using the same format as <varname>DNS</varname> and + <varname>DNSEx</varname> described above. See the description of <varname>FallbackDNS=</varname> in + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for + the description of when those servers are used.</para> + + <para><varname>CurrentDNSServer</varname> and <varname>CurrentDNSServerEx</varname> specify the server + that is currently used for query resolution, in the same format as a single entry in the + <varname>DNS</varname> and <varname>DNSEx</varname> arrays described above.</para> + + <para>Similarly, the <varname>Domains</varname> property contains an array of all search and routing + domains currently used by <filename>systemd-resolved</filename>. Each entry consists of a network + interface index (again, 0 encodes system-wide entries), the actual domain name, and whether the entry + is used only for routing (true) or for both routing and searching (false).</para> + + <para>The <varname>TransactionStatistics</varname> property contains information about the number of + transactions <filename>systemd-resolved</filename> has processed. It contains a pair of unsigned 64-bit counters, the first + containing the number of currently ongoing transactions, the second the number of total transactions + <filename>systemd-resolved</filename> is processing or has processed. The latter value may be reset using the + <function>ResetStatistics()</function> method described above. Note that the number of transactions does + not directly map to the number of issued resolver bus method calls. While simple look-ups usually require a + single transaction only, more complex look-ups might result in more, for example when CNAMEs or DNSSEC + are in use.</para> + + <para>The <varname>CacheStatistics</varname> property contains information about the executed cache + operations so far. It exposes three 64-bit counters: the first being the total number of current cache + entries (both positive and negative), the second the number of cache hits, and the third the number of + cache misses. The latter counters may be reset using <function>ResetStatistics()</function> (see + above).</para> + + <para>The <varname>DNSSEC</varname> property specifies current status of DNSSEC validation. It is one + of <literal>yes</literal> (validation is enforced), <literal>no</literal> (no validation is done), + <literal>allow-downgrade</literal> (validation is done if the current DNS server supports it). See the + description of <varname>DNSSEC=</varname> in + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + + <para>The <varname>DNSSECStatistics</varname> property contains information about the DNSSEC + validations executed so far. It contains four 64-bit counters: the number of secure, insecure, bogus, + and indeterminate DNSSEC validations so far. The counters are increased for each validated RRset, and + each non-existence proof. The secure counter is increased for each operation that successfully verified + a signed reply, the insecure counter is increased for each operation that successfully verified that an + unsigned reply is rightfully unsigned. The bogus counter is increased for each operation where the + validation did not check out and the data is likely to have been tempered with. Finally the + indeterminate counter is increased for each operation which did not complete because the necessary keys + could not be acquired or the cryptographic algorithms were unknown.</para> + + <para>The <varname>DNSSECSupported</varname> boolean property reports whether DNSSEC is enabled and + the selected DNS servers support it. It combines information about system-wide and per-link DNS + settings (see below), and only reports true if DNSSEC is enabled and supported on every interface for + which DNS is configured and for the system-wide settings if there are any. Note that <filename>systemd-resolved</filename> assumes + DNSSEC is supported by DNS servers until it verifies that this is not the case. Thus, the reported + value may initially be true, until the first transactions are executed.</para> + + <para>The <varname>DNSOverTLS</varname> boolean property reports whether DNS-over-TLS is enabled. + </para> + + <para>The <varname>ResolvConfMode</varname> property exposes how <filename>/etc/resolv.conf</filename> + is managed on the host. Currently, the values <literal>uplink</literal>, <literal>stub</literal>, + <literal>static</literal> (these three correspond to the three different files + <filename>systemd-resolved.service</filename> provides), <literal>foreign</literal> (the file is + managed by admin or another service, <filename>systemd-resolved.service</filename> just consumes it), + <literal>missing</literal> (<filename>/etc/resolv.conf</filename> is missing).</para> + + <para>The <varname>DNSStubListener</varname> property reports whether the stub listener on port 53 is + enabled. Possible values are <literal>yes</literal> (enabled), <literal>no</literal> (disabled), + <literal>udp</literal> (only the UDP listener is enabled), and <literal>tcp</literal> (only the TCP + listener is enabled).</para> + </refsect2> + </refsect1> + + <refsect1> + <title>Link Object</title> + + <programlisting executable="systemd-resolved" node="/org/freedesktop/resolve1/link/_1" interface="org.freedesktop.resolve1.Link"> +node /org/freedesktop/resolve1/link/_1 { + interface org.freedesktop.resolve1.Link { + methods: + SetDNS(in a(iay) addresses); + SetDNSEx(in a(iayqs) addresses); + SetDomains(in a(sb) domains); + SetDefaultRoute(in b enable); + SetLLMNR(in s mode); + SetMulticastDNS(in s mode); + SetDNSOverTLS(in s mode); + SetDNSSEC(in s mode); + SetDNSSECNegativeTrustAnchors(in as names); + Revert(); + properties: + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly t ScopesMask = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly a(iay) DNS = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly a(iayqs) DNSEx = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly (iay) CurrentDNSServer = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly (iayqs) CurrentDNSServerEx = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly a(sb) Domains = [...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly b DefaultRoute = ...; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s LLMNR = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s MulticastDNS = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s DNSOverTLS = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly s DNSSEC = '...'; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly as DNSSECNegativeTrustAnchors = ['...', ...]; + @org.freedesktop.DBus.Property.EmitsChangedSignal("false") + readonly b DNSSECSupported = ...; + }; + interface org.freedesktop.DBus.Peer { ... }; + interface org.freedesktop.DBus.Introspectable { ... }; + interface org.freedesktop.DBus.Properties { ... }; +}; + </programlisting> + + <!--property DNSSECNegativeTrustAnchors is not documented!--> + + <!--Autogenerated cross-references for systemd.directives, do not edit--> + + <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Link"/> + + <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Link"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDNS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDNSEx()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDomains()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDefaultRoute()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetLLMNR()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetMulticastDNS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDNSOverTLS()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDNSSEC()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="SetDNSSECNegativeTrustAnchors()"/> + + <variablelist class="dbus-method" generated="True" extra-ref="Revert()"/> + + <variablelist class="dbus-property" generated="True" extra-ref="ScopesMask"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSEx"/> + + <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServer"/> + + <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServerEx"/> + + <variablelist class="dbus-property" generated="True" extra-ref="Domains"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DefaultRoute"/> + + <variablelist class="dbus-property" generated="True" extra-ref="LLMNR"/> + + <variablelist class="dbus-property" generated="True" extra-ref="MulticastDNS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSOverTLS"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSEC"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSECNegativeTrustAnchors"/> + + <variablelist class="dbus-property" generated="True" extra-ref="DNSSECSupported"/> + + <!--End of Autogenerated section--> + + <para>For each Linux network interface a "Link" object is created which exposes per-link DNS + configuration and state. Use <function>GetLink()</function> on the Manager interface to retrieve the + object path for a link object given the network interface index (see above).</para> + + <refsect2> + <title>Methods</title> + + <para>The various methods exposed by the Link interface are equivalent to their similarly named + counterparts on the Manager interface. e.g. <function>SetDNS()</function> on the Link object maps to + <function>SetLinkDNS()</function> on the Manager object, the main difference being that the later + expects an interface index to be specified. Invoking the methods on the Manager interface has the + benefit of reducing roundtrips, as it is not necessary to first request the Link object path via + <function>GetLink()</function> before invoking the methods. The same relationship holds for + <function>SetDNSEx()</function>, <function>SetDomains()</function>, + <function>SetDefaultRoute()</function>, <function>SetLLMNR()</function>, + <function>SetMulticastDNS()</function>, <function>SetDNSOverTLS()</function>, + <function>SetDNSSEC()</function>, <function>SetDNSSECNegativeTrustAnchors()</function>, and + <function>Revert()</function>. For further details on these methods see the + <interfacename>Manager</interfacename> documentation above.</para> + </refsect2> + + <refsect2> + <title>Properties</title> + + <para><varname>ScopesMask</varname> defines which resolver scopes are currently active on this + interface. This 64-bit unsigned integer field is a bit mask consisting of a subset of the bits of the + flags parameter describe above. Specifically, it may have the DNS, LLMNR and MDNS bits (the latter in + IPv4 and IPv6 flavours) set. Each individual bit is set when the protocol applies to a specific + interface and is enabled for it. It is unset otherwise. Specifically, a multicast-capable interface in + the "UP" state with an IP address is suitable for LLMNR or MulticastDNS, and any interface that is UP and + has an IP address is suitable for DNS. Note the relationship of the bits exposed here with the LLMNR + and MulticastDNS properties also exposed on the Link interface. The latter expose what is *configured* + to be used on the interface, the former expose what is actually used on the interface, taking into + account the abilities of the interface.</para> + + <para><varname>DNSSECSupported</varname> exposes a boolean field that indicates whether DNSSEC is + currently configured and in use on the interface. Note that if DNSSEC is enabled on an interface, it is + assumed available until it is detected that the configured server does not actually support it. Thus, + this property may initially report that DNSSEC is supported on an interface.</para> + + <para><varname>DefaultRoute</varname> exposes a boolean field that indicates whether the interface will + be used as default route for name queries. See <function>SetLinkDefaultRoute()</function> above.</para> + + <para>The other properties reflect the state of the various configuration settings for the link which + may be set with the various methods calls such as <function>SetDNS()</function> or + <function>SetLLMNR()</function>.</para> + </refsect2> + </refsect1> + + <refsect1> + <title>Common Errors</title> + + <para>Many bus methods <filename>systemd-resolved</filename> exposes (in particular the resolver methods such + as <function>ResolveHostname()</function> on the <interfacename>Manager</interfacename> interface) may return + some of the following errors:</para> + + <variablelist> + <varlistentry><term><constant>org.freedesktop.resolve1.NoNameServers</constant></term> + <listitem><para>No suitable DNS servers were found to resolve a request.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.InvalidReply</constant></term> + <listitem><para>A response from the selected DNS server was not understood.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchRR</constant></term> + <listitem><para>The requested name exists, but there is no resource record of the requested type for + it. (This is the DNS NODATA case).</para></listitem></varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.CNameLoop</constant></term> + <listitem><para>The look-up failed because a CNAME or DNAME loop was detected.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.Aborted</constant></term> + <listitem><para>The look-up was aborted because the selected protocol became unavailable while the + operation was ongoing.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchService</constant></term> + <listitem><para>A service look-up was successful, but the <constant class="dns">SRV</constant> record + reported that the service is not available.</para></listitem></varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.DnssecFailed</constant></term> + <listitem><para>The acquired response did not pass DNSSEC validation.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.NoTrustAnchor</constant></term> + <listitem><para>No chain of trust could be established for the response to a configured DNSSEC trust + anchor.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.ResourceRecordTypeUnsupported</constant></term> + <listitem><para>The requested resource record type is not supported on the selected DNS servers. This + error is generated for example when an RRSIG record is requested from a DNS server that does not + support DNSSEC.</para></listitem> + + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchLink</constant></term> + <listitem><para>No network interface with the specified network interface index exists. + </para></listitem></varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.LinkBusy</constant></term> + <listitem><para>The requested configuration change could not be made because + <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + already took possession of the interface and supplied configuration data for it.</para></listitem> + </varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.NetworkDown</constant></term> + <listitem><para>The requested look-up failed because the system is currently not connected to any + suitable network.</para></listitem></varlistentry> + + <varlistentry><term><constant>org.freedesktop.resolve1.DnsError.NXDOMAIN</constant></term> + <term><constant>org.freedesktop.resolve1.DnsError.REFUSED</constant></term> + <term>...</term> + <listitem><para>The look-up failed with a DNS return code reporting a failure. The error names used as + suffixes here are defined in by IANA in + <ulink url="https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6">DNS RCODEs</ulink>. + </para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Examples</title> + + <example> + <title>Introspect <interfacename>org.freedesktop.resolve1.Manager</interfacename> on the bus</title> + + <programlisting> +$ gdbus introspect --system \ + --dest org.freedesktop.resolve1 \ + --object-path /org/freedesktop/resolve1 + </programlisting> + </example> + + <example> + <title>Introspect <interfacename>org.freedesktop.resolve1.Link</interfacename> on the bus</title> + + <programlisting> +$ gdbus introspect --system \ + --dest org.freedesktop.resolve1 \ + --object-path /org/freedesktop/resolve1/link/_11 + </programlisting> + </example> + </refsect1> + + <xi:include href="org.freedesktop.locale1.xml" xpointer="versioning"/> +</refentry> |