Handle EDNS version downgrade

dns/client.go

@@ -242,9 +242,6 @@ func (c *Client) Exchange(ctx context.Context, transport adapter.DNSTransport, m
 		response.Extra = common.Filter(response.Extra, func(it dns.RR) bool {
 			return it.Header().Rrtype != dns.TypeOPT
 		})
-		if requestEDNSOpt != nil {
-			response.SetEdns0(responseEDNSOpt.UDPSize(), responseEDNSOpt.Do())
-		}
 	}
 	logExchangedResponse(c.logger, ctx, response, timeToLive)
 	return response, err

option/rule_set.go

@@ -1,8 +1,6 @@
 package option
 
 import (
-	"net/url"
-	"path/filepath"
 	"reflect"
 
 	C "github.com/sagernet/sing-box/constant"
@@ -29,18 +27,6 @@ type _RuleSet struct {
 type RuleSet _RuleSet
 
 func (r RuleSet) MarshalJSON() ([]byte, error) {
-	if r.Type != C.RuleSetTypeInline {
-		var defaultFormat string
-		switch r.Type {
-		case C.RuleSetTypeLocal:
-			defaultFormat = ruleSetDefaultFormat(r.LocalOptions.Path)
-		case C.RuleSetTypeRemote:
-			defaultFormat = ruleSetDefaultFormat(r.RemoteOptions.URL)
-		}
-		if r.Format == defaultFormat {
-			r.Format = ""
-		}
-	}
 	var v any
 	switch r.Type {
 	case "", C.RuleSetTypeInline:
@@ -76,19 +62,7 @@ func (r *RuleSet) UnmarshalJSON(bytes []byte) error {
 	default:
 		return E.New("unknown rule-set type: " + r.Type)
 	}
-	err = badjson.UnmarshallExcluded(bytes, (*_RuleSet)(r), v)
-	if err != nil {
-		return err
-	}
 	if r.Type != C.RuleSetTypeInline {
-		if r.Format == "" {
-			switch r.Type {
-			case C.RuleSetTypeLocal:
-				r.Format = ruleSetDefaultFormat(r.LocalOptions.Path)
-			case C.RuleSetTypeRemote:
-				r.Format = ruleSetDefaultFormat(r.RemoteOptions.URL)
-			}
-		}
 		switch r.Format {
 		case "":
 			return E.New("missing format")
@@ -99,23 +73,13 @@ func (r *RuleSet) UnmarshalJSON(bytes []byte) error {
 	} else {
 		r.Format = ""
 	}
+	err = badjson.UnmarshallExcluded(bytes, (*_RuleSet)(r), v)
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
-func ruleSetDefaultFormat(path string) string {
-	if pathURL, err := url.Parse(path); err == nil {
-		path = pathURL.Path
-	}
-	switch filepath.Ext(path) {
-	case ".json":
-		return C.RuleSetFormatSource
-	case ".srs":
-		return C.RuleSetFormatBinary
-	default:
-		return ""
-	}
-}
-
 type LocalRuleSet struct {
 	Path string `json:"path,omitempty"`
 }