[chore] Validate/set account domain (#619)

* add miekg/dns dependency

* set/validate accountDomain

vendor/golang.org/x/net/ipv6/icmp.go

@@ -0,0 +1,60 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ipv6
+
+import "golang.org/x/net/internal/iana"
+
+// BUG(mikio): On Windows, methods related to ICMPFilter are not
+// implemented.
+
+// An ICMPType represents a type of ICMP message.
+type ICMPType int
+
+func (typ ICMPType) String() string {
+	s, ok := icmpTypes[typ]
+	if !ok {
+		return "<nil>"
+	}
+	return s
+}
+
+// Protocol returns the ICMPv6 protocol number.
+func (typ ICMPType) Protocol() int {
+	return iana.ProtocolIPv6ICMP
+}
+
+// An ICMPFilter represents an ICMP message filter for incoming
+// packets. The filter belongs to a packet delivery path on a host and
+// it cannot interact with forwarding packets or tunnel-outer packets.
+//
+// Note: RFC 8200 defines a reasonable role model. A node means a
+// device that implements IP. A router means a node that forwards IP
+// packets not explicitly addressed to itself, and a host means a node
+// that is not a router.
+type ICMPFilter struct {
+	icmpv6Filter
+}
+
+// Accept accepts incoming ICMP packets including the type field value
+// typ.
+func (f *ICMPFilter) Accept(typ ICMPType) {
+	f.accept(typ)
+}
+
+// Block blocks incoming ICMP packets including the type field value
+// typ.
+func (f *ICMPFilter) Block(typ ICMPType) {
+	f.block(typ)
+}
+
+// SetAll sets the filter action to the filter.
+func (f *ICMPFilter) SetAll(block bool) {
+	f.setAll(block)
+}
+
+// WillBlock reports whether the ICMP type will be blocked.
+func (f *ICMPFilter) WillBlock(typ ICMPType) bool {
+	return f.willBlock(typ)
+}