mirror of
https://github.com/XTLS/Xray-core.git
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313 lines
8.6 KiB
Go
313 lines
8.6 KiB
Go
// Package dns is an implementation of core.DNS feature.
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package dns
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//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
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import (
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"context"
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"fmt"
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"strings"
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"sync"
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"github.com/xtls/xray-core/common"
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"github.com/xtls/xray-core/common/errors"
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"github.com/xtls/xray-core/common/matcher/geoip"
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"github.com/xtls/xray-core/common/matcher/str"
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"github.com/xtls/xray-core/common/net"
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"github.com/xtls/xray-core/common/session"
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"github.com/xtls/xray-core/features"
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"github.com/xtls/xray-core/features/dns"
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)
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// DNS is a DNS rely server.
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type DNS struct {
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sync.Mutex
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tag string
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cacheStrategy CacheStrategy
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disableFallback bool
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ipOption *dns.IPOption
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hosts *StaticHosts
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clients []*Client
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ctx context.Context
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domainMatcher str.IndexMatcher
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matcherInfos []DomainMatcherInfo
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}
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// DomainMatcherInfo contains information attached to index returned by Server.domainMatcher
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type DomainMatcherInfo struct {
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clientIdx uint16
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domainRuleIdx uint16
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}
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// New creates a new DNS server with given configuration.
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func New(ctx context.Context, config *Config) (*DNS, error) {
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var tag string
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if len(config.Tag) > 0 {
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tag = config.Tag
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} else {
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tag = generateRandomTag()
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}
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var clientIP net.IP
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switch len(config.ClientIp) {
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case 0, net.IPv4len, net.IPv6len:
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clientIP = net.IP(config.ClientIp)
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default:
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return nil, newError("unexpected client IP length ", len(config.ClientIp))
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}
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var ipOption *dns.IPOption
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switch config.QueryStrategy {
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case QueryStrategy_USE_IP:
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ipOption = &dns.IPOption{
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IPv4Enable: true,
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IPv6Enable: true,
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FakeEnable: false,
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}
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case QueryStrategy_USE_IP4:
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ipOption = &dns.IPOption{
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IPv4Enable: true,
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IPv6Enable: false,
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FakeEnable: false,
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}
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case QueryStrategy_USE_IP6:
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ipOption = &dns.IPOption{
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IPv4Enable: false,
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IPv6Enable: true,
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FakeEnable: false,
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}
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}
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hosts, err := NewStaticHosts(config.StaticHosts, config.Hosts)
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if err != nil {
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return nil, newError("failed to create hosts").Base(err)
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}
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clients := []*Client{}
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domainRuleCount := 0
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for _, ns := range config.NameServer {
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domainRuleCount += len(ns.PrioritizedDomain)
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}
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// MatcherInfos is ensured to cover the maximum index domainMatcher could return, where matcher's index starts from 1
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matcherInfos := make([]DomainMatcherInfo, domainRuleCount+1)
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domainMatcher := &str.MatcherGroup{}
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geoipContainer := geoip.GeoIPMatcherContainer{}
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for _, endpoint := range config.NameServers {
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features.PrintDeprecatedFeatureWarning("simple DNS server")
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client, err := NewSimpleClient(ctx, endpoint, clientIP)
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if err != nil {
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return nil, newError("failed to create client").Base(err)
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}
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clients = append(clients, client)
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}
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for _, ns := range config.NameServer {
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clientIdx := len(clients)
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updateDomain := func(domainRule str.Matcher, originalRuleIdx int, matcherInfos []DomainMatcherInfo) error {
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midx := domainMatcher.Add(domainRule)
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matcherInfos[midx] = DomainMatcherInfo{
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clientIdx: uint16(clientIdx),
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domainRuleIdx: uint16(originalRuleIdx),
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}
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return nil
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}
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myClientIP := clientIP
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switch len(ns.ClientIp) {
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case net.IPv4len, net.IPv6len:
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myClientIP = net.IP(ns.ClientIp)
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}
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client, err := NewClient(ctx, ns, myClientIP, geoipContainer, &matcherInfos, updateDomain)
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if err != nil {
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return nil, newError("failed to create client").Base(err)
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}
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clients = append(clients, client)
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}
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// If there is no DNS client in config, add a `localhost` DNS client
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if len(clients) == 0 {
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clients = append(clients, NewLocalDNSClient())
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}
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return &DNS{
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tag: tag,
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hosts: hosts,
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ipOption: ipOption,
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clients: clients,
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ctx: ctx,
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domainMatcher: domainMatcher,
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matcherInfos: matcherInfos,
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cacheStrategy: config.CacheStrategy,
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disableFallback: config.DisableFallback,
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}, nil
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}
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// Type implements common.HasType.
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func (*DNS) Type() interface{} {
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return dns.ClientType()
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}
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// Start implements common.Runnable.
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func (s *DNS) Start() error {
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return nil
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}
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// Close implements common.Closable.
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func (s *DNS) Close() error {
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return nil
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}
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// IsOwnLink implements proxy.dns.ownLinkVerifier
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func (s *DNS) IsOwnLink(ctx context.Context) bool {
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inbound := session.InboundFromContext(ctx)
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return inbound != nil && inbound.Tag == s.tag
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}
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// LookupIP implements dns.Client.
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func (s *DNS) LookupIP(domain string) ([]net.IP, error) {
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return s.lookupIPInternal(domain, s.ipOption.Copy())
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}
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// LookupOptions implements dns.Client.
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func (s *DNS) LookupOptions(domain string, opts ...dns.Option) ([]net.IP, error) {
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opt := s.ipOption.Copy()
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for _, o := range opts {
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if o != nil {
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o(opt)
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}
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}
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return s.lookupIPInternal(domain, opt)
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}
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// LookupIPv4 implements dns.IPv4Lookup.
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func (s *DNS) LookupIPv4(domain string) ([]net.IP, error) {
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return s.lookupIPInternal(domain, &dns.IPOption{
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IPv4Enable: true,
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})
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}
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// LookupIPv6 implements dns.IPv6Lookup.
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func (s *DNS) LookupIPv6(domain string) ([]net.IP, error) {
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return s.lookupIPInternal(domain, &dns.IPOption{
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IPv6Enable: true,
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})
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}
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func (s *DNS) lookupIPInternal(domain string, option *dns.IPOption) ([]net.IP, error) {
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if domain == "" {
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return nil, newError("empty domain name")
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}
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if isQuery(option) {
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return nil, newError("empty option: Impossible.").AtWarning()
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}
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// Normalize the FQDN form query
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if strings.HasSuffix(domain, ".") {
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domain = domain[:len(domain)-1]
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}
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// Static host lookup
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switch addrs := s.hosts.Lookup(domain, option); {
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case addrs == nil: // Domain not recorded in static host
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break
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case len(addrs) == 0: // Domain recorded, but no valid IP returned (e.g. IPv4 address with only IPv6 enabled)
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return nil, dns.ErrEmptyResponse
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case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Domain replacement
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newError("domain replaced: ", domain, " -> ", addrs[0].Domain()).WriteToLog()
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domain = addrs[0].Domain()
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default:
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// Successfully found ip records in static host.
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// Skip hosts mapping result in FakeDNS query.
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if isIPQuery(option) {
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newError("returning ", len(addrs), " IP(s) for domain ", domain, " -> ", addrs).WriteToLog()
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return toNetIP(addrs)
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}
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}
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// Name servers lookup
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errs := []error{}
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ctx := session.ContextWithInbound(s.ctx, &session.Inbound{Tag: s.tag})
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for _, client := range s.sortClients(domain, option) {
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ips, err := client.QueryIP(ctx, domain, *option, s.cacheStrategy)
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if len(ips) > 0 {
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return ips, nil
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}
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if err != nil {
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newError("failed to lookup ip for domain ", domain, " at server ", client.Name()).Base(err).WriteToLog()
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errs = append(errs, err)
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}
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if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch {
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return nil, err
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}
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}
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return nil, newError("returning nil for domain ", domain).Base(errors.Combine(errs...))
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}
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func (s *DNS) sortClients(domain string, option *dns.IPOption) []*Client {
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clients := make([]*Client, 0, len(s.clients))
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clientUsed := make([]bool, len(s.clients))
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clientNames := make([]string, 0, len(s.clients))
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domainRules := []string{}
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defer func() {
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if len(domainRules) > 0 {
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newError("domain ", domain, " matches following rules: ", domainRules).AtDebug().WriteToLog()
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}
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if len(clientNames) > 0 {
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newError("domain ", domain, " will use DNS in order: ", clientNames).AtDebug().WriteToLog()
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}
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if len(clients) == 0 {
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clients = append(clients, s.clients[0])
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clientNames = append(clientNames, s.clients[0].Name())
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newError("domain ", domain, " will use the first DNS: ", clientNames).AtDebug().WriteToLog()
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}
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}()
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// Priority domain matching
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for _, match := range s.domainMatcher.Match(domain) {
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info := s.matcherInfos[match]
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client := s.clients[info.clientIdx]
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domainRule := client.domains[info.domainRuleIdx]
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if !canQueryOnClient(option, client) {
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newError("skipping the client " + client.Name()).AtDebug().WriteToLog()
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continue
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}
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domainRules = append(domainRules, fmt.Sprintf("%s(DNS idx:%d)", domainRule, info.clientIdx))
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if clientUsed[info.clientIdx] {
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continue
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}
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clientUsed[info.clientIdx] = true
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clients = append(clients, client)
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clientNames = append(clientNames, client.Name())
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}
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if !s.disableFallback {
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// Default round-robin query
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for idx, client := range s.clients {
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if clientUsed[idx] || client.skipFallback {
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continue
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}
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if !canQueryOnClient(option, client) {
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newError("skipping the client " + client.Name()).AtDebug().WriteToLog()
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continue
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}
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clientUsed[idx] = true
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clients = append(clients, client)
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clientNames = append(clientNames, client.Name())
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}
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}
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return clients
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}
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func init() {
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common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
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return New(ctx, config.(*Config))
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}))
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}
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