refactor: DNS

dns/transport/fakeip/store.go

@@ -0,0 +1,118 @@
+package fakeip
+
+import (
+	"context"
+	"net/netip"
+
+	"github.com/sagernet/sing-box/adapter"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+	"github.com/sagernet/sing/service"
+)
+
+var _ adapter.FakeIPStore = (*Store)(nil)
+
+type Store struct {
+	ctx          context.Context
+	logger       logger.Logger
+	inet4Range   netip.Prefix
+	inet6Range   netip.Prefix
+	storage      adapter.FakeIPStorage
+	inet4Current netip.Addr
+	inet6Current netip.Addr
+}
+
+func NewStore(ctx context.Context, logger logger.Logger, inet4Range netip.Prefix, inet6Range netip.Prefix) *Store {
+	return &Store{
+		ctx:        ctx,
+		logger:     logger,
+		inet4Range: inet4Range,
+		inet6Range: inet6Range,
+	}
+}
+
+func (s *Store) Start() error {
+	var storage adapter.FakeIPStorage
+	cacheFile := service.FromContext[adapter.CacheFile](s.ctx)
+	if cacheFile != nil && cacheFile.StoreFakeIP() {
+		storage = cacheFile
+	}
+	if storage == nil {
+		storage = NewMemoryStorage()
+	}
+	metadata := storage.FakeIPMetadata()
+	if metadata != nil && metadata.Inet4Range == s.inet4Range && metadata.Inet6Range == s.inet6Range {
+		s.inet4Current = metadata.Inet4Current
+		s.inet6Current = metadata.Inet6Current
+	} else {
+		if s.inet4Range.IsValid() {
+			s.inet4Current = s.inet4Range.Addr().Next().Next()
+		}
+		if s.inet6Range.IsValid() {
+			s.inet6Current = s.inet6Range.Addr().Next().Next()
+		}
+		_ = storage.FakeIPReset()
+	}
+	s.storage = storage
+	return nil
+}
+
+func (s *Store) Contains(address netip.Addr) bool {
+	return s.inet4Range.Contains(address) || s.inet6Range.Contains(address)
+}
+
+func (s *Store) Close() error {
+	if s.storage == nil {
+		return nil
+	}
+	return s.storage.FakeIPSaveMetadata(&adapter.FakeIPMetadata{
+		Inet4Range:   s.inet4Range,
+		Inet6Range:   s.inet6Range,
+		Inet4Current: s.inet4Current,
+		Inet6Current: s.inet6Current,
+	})
+}
+
+func (s *Store) Create(domain string, isIPv6 bool) (netip.Addr, error) {
+	if address, loaded := s.storage.FakeIPLoadDomain(domain, isIPv6); loaded {
+		return address, nil
+	}
+	var address netip.Addr
+	if !isIPv6 {
+		if !s.inet4Current.IsValid() {
+			return netip.Addr{}, E.New("missing IPv4 fakeip address range")
+		}
+		nextAddress := s.inet4Current.Next()
+		if !s.inet4Range.Contains(nextAddress) {
+			nextAddress = s.inet4Range.Addr().Next().Next()
+		}
+		s.inet4Current = nextAddress
+		address = nextAddress
+	} else {
+		if !s.inet6Current.IsValid() {
+			return netip.Addr{}, E.New("missing IPv6 fakeip address range")
+		}
+		nextAddress := s.inet6Current.Next()
+		if !s.inet6Range.Contains(nextAddress) {
+			nextAddress = s.inet6Range.Addr().Next().Next()
+		}
+		s.inet6Current = nextAddress
+		address = nextAddress
+	}
+	s.storage.FakeIPStoreAsync(address, domain, s.logger)
+	s.storage.FakeIPSaveMetadataAsync(&adapter.FakeIPMetadata{
+		Inet4Range:   s.inet4Range,
+		Inet6Range:   s.inet6Range,
+		Inet4Current: s.inet4Current,
+		Inet6Current: s.inet6Current,
+	})
+	return address, nil
+}
+
+func (s *Store) Lookup(address netip.Addr) (string, bool) {
+	return s.storage.FakeIPLoad(address)
+}
+
+func (s *Store) Reset() error {
+	return s.storage.FakeIPReset()
+}