mirror of
https://github.com/SagerNet/sing-box.git
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31d88ac7d3
We mistakenly believed that `libresolv`'s `search` function worked correctly in NetworkExtension, but it seems only `getaddrinfo` does. This commit changes the behavior of the `local` DNS server in NetworkExtension to prefer DHCP, falling back to `getaddrinfo` if DHCP servers are unavailable. It's worth noting that `prefer_go` does not disable DHCP since it respects Dial Fields, but `getaddrinfo` does the opposite. The new behavior only applies to NetworkExtension, not to all scenarios (primarily command-line binaries) as it did previously. In addition, this commit also improves the DHCP DNS server to use the same robust query logic as `local`.
94 lines
2.5 KiB
Go
94 lines
2.5 KiB
Go
//go:build !darwin
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package local
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import (
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"context"
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"github.com/sagernet/sing-box/adapter"
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C "github.com/sagernet/sing-box/constant"
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"github.com/sagernet/sing-box/dns"
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"github.com/sagernet/sing-box/dns/transport/hosts"
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"github.com/sagernet/sing-box/log"
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"github.com/sagernet/sing-box/option"
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E "github.com/sagernet/sing/common/exceptions"
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"github.com/sagernet/sing/common/logger"
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N "github.com/sagernet/sing/common/network"
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mDNS "github.com/miekg/dns"
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)
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func RegisterTransport(registry *dns.TransportRegistry) {
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dns.RegisterTransport[option.LocalDNSServerOptions](registry, C.DNSTypeLocal, NewTransport)
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}
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var _ adapter.DNSTransport = (*Transport)(nil)
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type Transport struct {
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dns.TransportAdapter
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ctx context.Context
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logger logger.ContextLogger
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hosts *hosts.File
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dialer N.Dialer
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preferGo bool
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resolved ResolvedResolver
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}
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func NewTransport(ctx context.Context, logger log.ContextLogger, tag string, options option.LocalDNSServerOptions) (adapter.DNSTransport, error) {
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transportDialer, err := dns.NewLocalDialer(ctx, options)
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if err != nil {
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return nil, err
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}
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return &Transport{
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TransportAdapter: dns.NewTransportAdapterWithLocalOptions(C.DNSTypeLocal, tag, options),
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ctx: ctx,
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logger: logger,
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hosts: hosts.NewFile(hosts.DefaultPath),
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dialer: transportDialer,
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preferGo: options.PreferGo,
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}, nil
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}
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func (t *Transport) Start(stage adapter.StartStage) error {
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switch stage {
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case adapter.StartStateInitialize:
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if !t.preferGo {
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resolvedResolver, err := NewResolvedResolver(t.ctx, t.logger)
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if err == nil {
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err = resolvedResolver.Start()
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if err == nil {
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t.resolved = resolvedResolver
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} else {
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t.logger.Warn(E.Cause(err, "initialize resolved resolver"))
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}
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}
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}
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}
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return nil
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}
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func (t *Transport) Close() error {
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if t.resolved != nil {
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return t.resolved.Close()
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}
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return nil
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}
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func (t *Transport) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, error) {
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if t.resolved != nil {
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resolverObject := t.resolved.Object()
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if resolverObject != nil {
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return t.resolved.Exchange(resolverObject, ctx, message)
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}
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}
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question := message.Question[0]
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domain := dns.FqdnToDomain(question.Name)
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if question.Qtype == mDNS.TypeA || question.Qtype == mDNS.TypeAAAA {
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addresses := t.hosts.Lookup(domain)
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if len(addresses) > 0 {
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return dns.FixedResponse(message.Id, question, addresses, C.DefaultDNSTTL), nil
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}
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}
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return t.exchange(ctx, message, domain)
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}
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