mirror of
https://github.com/SagerNet/sing-box.git
synced 2024-12-04 20:36:37 +00:00
282 lines
8.6 KiB
Go
282 lines
8.6 KiB
Go
package route
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import (
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"context"
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"errors"
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"net/netip"
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"strings"
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"time"
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"github.com/sagernet/sing-box/adapter"
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R "github.com/sagernet/sing-box/route/rule"
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"github.com/sagernet/sing-dns"
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"github.com/sagernet/sing/common/cache"
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E "github.com/sagernet/sing/common/exceptions"
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F "github.com/sagernet/sing/common/format"
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M "github.com/sagernet/sing/common/metadata"
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mDNS "github.com/miekg/dns"
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)
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type DNSReverseMapping struct {
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cache *cache.LruCache[netip.Addr, string]
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}
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func NewDNSReverseMapping() *DNSReverseMapping {
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return &DNSReverseMapping{
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cache: cache.New[netip.Addr, string](),
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}
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}
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func (m *DNSReverseMapping) Save(address netip.Addr, domain string, ttl int) {
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m.cache.StoreWithExpire(address, domain, time.Now().Add(time.Duration(ttl)*time.Second))
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}
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func (m *DNSReverseMapping) Query(address netip.Addr) (string, bool) {
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domain, loaded := m.cache.Load(address)
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return domain, loaded
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}
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func (r *Router) matchDNS(ctx context.Context, allowFakeIP bool, ruleIndex int, isAddressQuery bool) (dns.Transport, dns.QueryOptions, adapter.DNSRule, int) {
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metadata := adapter.ContextFrom(ctx)
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if metadata == nil {
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panic("no context")
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}
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var options dns.QueryOptions
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if ruleIndex < len(r.dnsRules) {
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dnsRules := r.dnsRules
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if ruleIndex != -1 {
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dnsRules = dnsRules[ruleIndex+1:]
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}
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for currentRuleIndex, rule := range dnsRules {
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if rule.WithAddressLimit() && !isAddressQuery {
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continue
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}
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metadata.ResetRuleCache()
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if rule.Match(metadata) {
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displayRuleIndex := currentRuleIndex
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if displayRuleIndex != -1 {
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displayRuleIndex += displayRuleIndex + 1
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}
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if routeAction, isRoute := rule.Action().(*R.RuleActionDNSRoute); isRoute {
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transport, loaded := r.transportMap[routeAction.Server]
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if !loaded {
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r.dnsLogger.ErrorContext(ctx, "transport not found: ", routeAction.Server)
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continue
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}
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_, isFakeIP := transport.(adapter.FakeIPTransport)
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if isFakeIP && !allowFakeIP {
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continue
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}
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options.DisableCache = isFakeIP || routeAction.DisableCache
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options.RewriteTTL = routeAction.RewriteTTL
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options.ClientSubnet = routeAction.ClientSubnet
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if domainStrategy, dsLoaded := r.transportDomainStrategy[transport]; dsLoaded {
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options.Strategy = domainStrategy
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} else {
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options.Strategy = r.defaultDomainStrategy
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}
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r.dnsLogger.DebugContext(ctx, "match[", displayRuleIndex, "] ", rule.String(), " => ", rule.Action())
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return transport, options, rule, currentRuleIndex
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} else {
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return nil, options, rule, currentRuleIndex
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}
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}
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}
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}
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if domainStrategy, dsLoaded := r.transportDomainStrategy[r.defaultTransport]; dsLoaded {
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options.Strategy = domainStrategy
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} else {
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options.Strategy = r.defaultDomainStrategy
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}
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return r.defaultTransport, options, nil, -1
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}
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func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, error) {
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if len(message.Question) > 0 {
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r.dnsLogger.DebugContext(ctx, "exchange ", formatQuestion(message.Question[0].String()))
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}
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var (
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response *mDNS.Msg
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cached bool
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transport dns.Transport
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err error
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)
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response, cached = r.dnsClient.ExchangeCache(ctx, message)
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if !cached {
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var metadata *adapter.InboundContext
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ctx, metadata = adapter.ExtendContext(ctx)
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metadata.Destination = M.Socksaddr{}
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if len(message.Question) > 0 {
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metadata.QueryType = message.Question[0].Qtype
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switch metadata.QueryType {
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case mDNS.TypeA:
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metadata.IPVersion = 4
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case mDNS.TypeAAAA:
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metadata.IPVersion = 6
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}
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metadata.Domain = fqdnToDomain(message.Question[0].Name)
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}
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var (
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options dns.QueryOptions
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rule adapter.DNSRule
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ruleIndex int
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)
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ruleIndex = -1
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for {
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dnsCtx := adapter.OverrideContext(ctx)
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var addressLimit bool
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transport, options, rule, ruleIndex = r.matchDNS(ctx, true, ruleIndex, isAddressQuery(message))
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if rule != nil && rule.WithAddressLimit() {
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addressLimit = true
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response, err = r.dnsClient.ExchangeWithResponseCheck(dnsCtx, transport, message, options, func(response *mDNS.Msg) bool {
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addresses, addrErr := dns.MessageToAddresses(response)
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if addrErr != nil {
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return false
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}
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metadata.DestinationAddresses = addresses
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return rule.MatchAddressLimit(metadata)
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})
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} else {
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addressLimit = false
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response, err = r.dnsClient.Exchange(dnsCtx, transport, message, options)
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}
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var rejected bool
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if err != nil {
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if errors.Is(err, dns.ErrResponseRejectedCached) {
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rejected = true
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r.dnsLogger.DebugContext(ctx, E.Cause(err, "response rejected for ", formatQuestion(message.Question[0].String())), " (cached)")
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} else if errors.Is(err, dns.ErrResponseRejected) {
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rejected = true
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r.dnsLogger.DebugContext(ctx, E.Cause(err, "response rejected for ", formatQuestion(message.Question[0].String())))
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} else if len(message.Question) > 0 {
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r.dnsLogger.ErrorContext(ctx, E.Cause(err, "exchange failed for ", formatQuestion(message.Question[0].String())))
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} else {
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r.dnsLogger.ErrorContext(ctx, E.Cause(err, "exchange failed for <empty query>"))
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}
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}
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if addressLimit && rejected {
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continue
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}
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break
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}
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}
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if err != nil {
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return nil, err
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}
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if r.dnsReverseMapping != nil && len(message.Question) > 0 && response != nil && len(response.Answer) > 0 {
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if _, isFakeIP := transport.(adapter.FakeIPTransport); !isFakeIP {
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for _, answer := range response.Answer {
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switch record := answer.(type) {
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case *mDNS.A:
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r.dnsReverseMapping.Save(M.AddrFromIP(record.A), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
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case *mDNS.AAAA:
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r.dnsReverseMapping.Save(M.AddrFromIP(record.AAAA), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
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}
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}
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}
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}
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return response, nil
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}
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func (r *Router) Lookup(ctx context.Context, domain string, strategy dns.DomainStrategy) ([]netip.Addr, error) {
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var (
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responseAddrs []netip.Addr
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cached bool
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err error
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)
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responseAddrs, cached = r.dnsClient.LookupCache(ctx, domain, strategy)
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if cached {
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if len(responseAddrs) == 0 {
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return nil, dns.RCodeNameError
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}
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return responseAddrs, nil
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}
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r.dnsLogger.DebugContext(ctx, "lookup domain ", domain)
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ctx, metadata := adapter.ExtendContext(ctx)
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metadata.Destination = M.Socksaddr{}
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metadata.Domain = domain
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var (
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transport dns.Transport
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options dns.QueryOptions
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rule adapter.DNSRule
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ruleIndex int
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)
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ruleIndex = -1
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for {
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dnsCtx := adapter.OverrideContext(ctx)
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var addressLimit bool
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transport, options, rule, ruleIndex = r.matchDNS(ctx, false, ruleIndex, true)
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if strategy != dns.DomainStrategyAsIS {
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options.Strategy = strategy
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}
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if rule != nil && rule.WithAddressLimit() {
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addressLimit = true
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responseAddrs, err = r.dnsClient.LookupWithResponseCheck(dnsCtx, transport, domain, options, func(responseAddrs []netip.Addr) bool {
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metadata.DestinationAddresses = responseAddrs
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return rule.MatchAddressLimit(metadata)
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})
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} else {
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addressLimit = false
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responseAddrs, err = r.dnsClient.Lookup(dnsCtx, transport, domain, options)
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}
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if err != nil {
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if errors.Is(err, dns.ErrResponseRejectedCached) {
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r.dnsLogger.DebugContext(ctx, "response rejected for ", domain, " (cached)")
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} else if errors.Is(err, dns.ErrResponseRejected) {
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r.dnsLogger.DebugContext(ctx, "response rejected for ", domain)
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} else {
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r.dnsLogger.ErrorContext(ctx, E.Cause(err, "lookup failed for ", domain))
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}
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} else if len(responseAddrs) == 0 {
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r.dnsLogger.ErrorContext(ctx, "lookup failed for ", domain, ": empty result")
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err = dns.RCodeNameError
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}
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if !addressLimit || err == nil {
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break
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}
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}
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if len(responseAddrs) > 0 {
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r.dnsLogger.InfoContext(ctx, "lookup succeed for ", domain, ": ", strings.Join(F.MapToString(responseAddrs), " "))
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}
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return responseAddrs, err
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}
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func (r *Router) LookupDefault(ctx context.Context, domain string) ([]netip.Addr, error) {
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return r.Lookup(ctx, domain, dns.DomainStrategyAsIS)
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}
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func (r *Router) ClearDNSCache() {
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r.dnsClient.ClearCache()
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if r.platformInterface != nil {
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r.platformInterface.ClearDNSCache()
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}
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}
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func isAddressQuery(message *mDNS.Msg) bool {
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for _, question := range message.Question {
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if question.Qtype == mDNS.TypeA || question.Qtype == mDNS.TypeAAAA || question.Qtype == mDNS.TypeHTTPS {
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return true
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}
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}
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return false
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}
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func fqdnToDomain(fqdn string) string {
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if mDNS.IsFqdn(fqdn) {
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return fqdn[:len(fqdn)-1]
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}
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return fqdn
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}
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func formatQuestion(string string) string {
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if strings.HasPrefix(string, ";") {
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string = string[1:]
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}
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string = strings.ReplaceAll(string, "\t", " ")
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for strings.Contains(string, " ") {
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string = strings.ReplaceAll(string, " ", " ")
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}
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return string
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}
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