chain works

vendor/github.com/armon/go-socks5/ruleset.go

@@ -0,0 +1,41 @@
+package socks5
+
+import (
+	"golang.org/x/net/context"
+)
+
+// RuleSet is used to provide custom rules to allow or prohibit actions
+type RuleSet interface {
+	Allow(ctx context.Context, req *Request) (context.Context, bool)
+}
+
+// PermitAll returns a RuleSet which allows all types of connections
+func PermitAll() RuleSet {
+	return &PermitCommand{true, true, true}
+}
+
+// PermitNone returns a RuleSet which disallows all types of connections
+func PermitNone() RuleSet {
+	return &PermitCommand{false, false, false}
+}
+
+// PermitCommand is an implementation of the RuleSet which
+// enables filtering supported commands
+type PermitCommand struct {
+	EnableConnect   bool
+	EnableBind      bool
+	EnableAssociate bool
+}
+
+func (p *PermitCommand) Allow(ctx context.Context, req *Request) (context.Context, bool) {
+	switch req.Command {
+	case ConnectCommand:
+		return ctx, p.EnableConnect
+	case BindCommand:
+		return ctx, p.EnableBind
+	case AssociateCommand:
+		return ctx, p.EnableAssociate
+	}
+
+	return ctx, false
+}