add plugin forward_edns0opt

plugin/enabled_plugins.go

@@ -49,6 +49,7 @@ import (
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/dual_selector"
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/ecs_handler"
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/forward"
+	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/forward_edns0opt"
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/hosts"
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/ipset"
 	_ "github.com/IrineSistiana/mosdns/v5/plugin/executable/metrics_collector"

plugin/executable/forward_edns0opt/forwarder.go

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2020-2022, IrineSistiana
+ *
+ * This file is part of mosdns.
+ *
+ * mosdns is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * mosdns is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package forwardedns0opt
+
+import (
+	"context"
+	"strconv"
+	"strings"
+
+	"github.com/IrineSistiana/mosdns/v5/pkg/query_context"
+	"github.com/IrineSistiana/mosdns/v5/plugin/executable/sequence"
+)
+
+const PluginType = "forward_edns0opt"
+
+func init() {
+	sequence.MustRegExecQuickSetup(PluginType, QuickSetup)
+}
+
+var _ sequence.RecursiveExecutable = (*forwarder)(nil)
+
+type forwarder struct {
+	forwardTypCodes map[uint32]struct{}
+}
+
+func (f *forwarder) Exec(ctx context.Context, qCtx *query_context.Context, next sequence.ChainWalker) error {
+	qOpt := qCtx.QOpt()
+	clientOpt := qCtx.ClientOpt()
+	if clientOpt != nil {
+		for _, o := range clientOpt.Option {
+			if _, ok := f.forwardTypCodes[uint32(o.Option())]; ok {
+				qOpt.Option = append(qOpt.Option, o)
+			}
+		}
+	}
+
+	err := next.ExecNext(ctx, qCtx)
+	if err != nil {
+		return err
+	}
+
+	upstreamOpt := qCtx.UpstreamOpt()
+	respOpt := qCtx.RespOpt()
+	if upstreamOpt != nil && respOpt != nil {
+		for _, o := range upstreamOpt.Option {
+			if _, ok := f.forwardTypCodes[uint32(o.Option())]; ok {
+				respOpt.Option = append(respOpt.Option, o)
+			}
+		}
+	}
+	return nil
+}
+
+// Format: [DNS EDNS0 Option Code] ...
+func QuickSetup(_ sequence.BQ, numbers string) (any, error) {
+	m := make(map[uint32]struct{})
+	for _, s := range strings.Fields(numbers) {
+		n, err := strconv.ParseUint(s, 10, 16)
+		if err != nil {
+			return nil, err
+		}
+		m[uint32(n)] = struct{}{}
+	}
+	return &forwarder{forwardTypCodes: m}, nil
+}