Make gtcpip public for external use

gtcpip/header/ndp_neighbor_solicit.go

@@ -0,0 +1,52 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package header
+
+import "github.com/sagernet/sing-tun/gtcpip"
+
+// NDPNeighborSolicit is an NDP Neighbor Solicitation message. It will only
+// contain the body of an ICMPv6 packet.
+//
+// See RFC 4861 section 4.3 for more details.
+type NDPNeighborSolicit []byte
+
+const (
+	// NDPNSMinimumSize is the minimum size of a valid NDP Neighbor
+	// Solicitation message (body of an ICMPv6 packet).
+	NDPNSMinimumSize = 20
+
+	// ndpNSTargetAddessOffset is the start of the Target Address
+	// field within an NDPNeighborSolicit.
+	ndpNSTargetAddessOffset = 4
+
+	// ndpNSOptionsOffset is the start of the NDP options in an
+	// NDPNeighborSolicit.
+	ndpNSOptionsOffset = ndpNSTargetAddessOffset + IPv6AddressSize
+)
+
+// TargetAddress returns the value within the Target Address field.
+func (b NDPNeighborSolicit) TargetAddress() tcpip.Address {
+	return tcpip.AddrFrom16Slice(b[ndpNSTargetAddessOffset:][:IPv6AddressSize])
+}
+
+// SetTargetAddress sets the value within the Target Address field.
+func (b NDPNeighborSolicit) SetTargetAddress(addr tcpip.Address) {
+	copy(b[ndpNSTargetAddessOffset:][:IPv6AddressSize], addr.AsSlice())
+}
+
+// Options returns an NDPOptions of the options body.
+func (b NDPNeighborSolicit) Options() NDPOptions {
+	return NDPOptions(b[ndpNSOptionsOffset:])
+}