Refactor geo resources

common/geoip/reader.go

@@ -0,0 +1,37 @@
+package geoip
+
+import (
+	"net/netip"
+
+	"github.com/oschwald/maxminddb-golang"
+	E "github.com/sagernet/sing/common/exceptions"
+	N "github.com/sagernet/sing/common/network"
+)
+
+type Reader struct {
+	reader *maxminddb.Reader
+}
+
+func Open(path string) (*Reader, []string, error) {
+	database, err := maxminddb.Open(path)
+	if err != nil {
+		return nil, nil, err
+	}
+	if database.Metadata.DatabaseType != "sing-geoip" {
+		database.Close()
+		return nil, nil, E.New("incorrect database type, expected sing-geoip, got ", database.Metadata.DatabaseType)
+	}
+	return &Reader{database}, database.Metadata.Languages, nil
+}
+
+func (r *Reader) Lookup(addr netip.Addr) string {
+	var code string
+	_ = r.reader.Lookup(addr.AsSlice(), &code)
+	if code != "" {
+		return code
+	}
+	if !N.IsPublicAddr(addr) {
+		return "private"
+	}
+	return "unknown"
+}