mirror of
https://github.com/tailscale/tailscale.git
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93 lines
2.9 KiB
Go
93 lines
2.9 KiB
Go
// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package dns
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import (
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"errors"
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"inet.af/netaddr"
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"tailscale.com/util/dnsname"
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)
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// An OSConfigurator applies DNS settings to the operating system.
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type OSConfigurator interface {
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// SetDNS updates the OS's DNS configuration to match cfg.
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// If cfg is the zero value, all Tailscale-related DNS
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// configuration is removed.
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// SetDNS must not be called after Close.
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SetDNS(cfg OSConfig) error
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// SupportsSplitDNS reports whether the configurator is capable of
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// installing a resolver only for specific DNS suffixes. If false,
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// the configurator can only set a global resolver.
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SupportsSplitDNS() bool
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// GetBaseConfig returns the OS's "base" configuration, i.e. the
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// resolver settings the OS would use without Tailscale
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// contributing any configuration.
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// GetBaseConfig must return the tailscale-free base config even
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// after SetDNS has been called to set a Tailscale configuration.
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// Only works when SupportsSplitDNS=false.
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// Implementations that don't support getting the base config must
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// return ErrGetBaseConfigNotSupported.
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GetBaseConfig() (OSConfig, error)
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// Close removes Tailscale-related DNS configuration from the OS.
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Close() error
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}
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// OSConfig is an OS DNS configuration.
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type OSConfig struct {
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// Nameservers are the IP addresses of the nameservers to use.
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Nameservers []netaddr.IP
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// SearchDomains are the domain suffixes to use when expanding
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// single-label name queries. SearchDomains is additive to
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// whatever non-Tailscale search domains the OS has.
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SearchDomains []dnsname.FQDN
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// MatchDomains are the DNS suffixes for which Nameservers should
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// be used. If empty, Nameservers is installed as the "primary" resolver.
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// A non-empty MatchDomains requests a "split DNS" configuration
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// from the OS, which will only work with OSConfigurators that
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// report SupportsSplitDNS()=true.
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MatchDomains []dnsname.FQDN
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}
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func (o OSConfig) IsZero() bool {
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return len(o.Nameservers) == 0 && len(o.SearchDomains) == 0 && len(o.MatchDomains) == 0
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}
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func (a OSConfig) Equal(b OSConfig) bool {
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if len(a.Nameservers) != len(b.Nameservers) {
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return false
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}
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if len(a.SearchDomains) != len(b.SearchDomains) {
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return false
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}
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if len(a.MatchDomains) != len(b.MatchDomains) {
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return false
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}
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for i := range a.Nameservers {
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if a.Nameservers[i] != b.Nameservers[i] {
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return false
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}
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}
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for i := range a.SearchDomains {
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if a.SearchDomains[i] != b.SearchDomains[i] {
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return false
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}
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}
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for i := range a.MatchDomains {
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if a.MatchDomains[i] != b.MatchDomains[i] {
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return false
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}
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}
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return true
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}
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// ErrGetBaseConfigNotSupported is the error
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// OSConfigurator.GetBaseConfig returns when the OSConfigurator
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// doesn't support reading the underlying configuration out of the OS.
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var ErrGetBaseConfigNotSupported = errors.New("getting OS base config is not supported")
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