Make gtcpip public for external use

gtcpip/header/ndp_neighbor_advert.go

@@ -0,0 +1,110 @@
+// 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"
+
+// NDPNeighborAdvert is an NDP Neighbor Advertisement message. It will
+// only contain the body of an ICMPv6 packet.
+//
+// See RFC 4861 section 4.4 for more details.
+type NDPNeighborAdvert []byte
+
+const (
+	// NDPNAMinimumSize is the minimum size of a valid NDP Neighbor
+	// Advertisement message (body of an ICMPv6 packet).
+	NDPNAMinimumSize = 20
+
+	// ndpNATargetAddressOffset is the start of the Target Address
+	// field within an NDPNeighborAdvert.
+	ndpNATargetAddressOffset = 4
+
+	// ndpNAOptionsOffset is the start of the NDP options in an
+	// NDPNeighborAdvert.
+	ndpNAOptionsOffset = ndpNATargetAddressOffset + IPv6AddressSize
+
+	// ndpNAFlagsOffset is the offset of the flags within an
+	// NDPNeighborAdvert
+	ndpNAFlagsOffset = 0
+
+	// ndpNARouterFlagMask is the mask of the Router Flag field in
+	// the flags byte within in an NDPNeighborAdvert.
+	ndpNARouterFlagMask = (1 << 7)
+
+	// ndpNASolicitedFlagMask is the mask of the Solicited Flag field in
+	// the flags byte within in an NDPNeighborAdvert.
+	ndpNASolicitedFlagMask = (1 << 6)
+
+	// ndpNAOverrideFlagMask is the mask of the Override Flag field in
+	// the flags byte within in an NDPNeighborAdvert.
+	ndpNAOverrideFlagMask = (1 << 5)
+)
+
+// TargetAddress returns the value within the Target Address field.
+func (b NDPNeighborAdvert) TargetAddress() tcpip.Address {
+	return tcpip.AddrFrom16Slice(b[ndpNATargetAddressOffset:][:IPv6AddressSize])
+}
+
+// SetTargetAddress sets the value within the Target Address field.
+func (b NDPNeighborAdvert) SetTargetAddress(addr tcpip.Address) {
+	copy(b[ndpNATargetAddressOffset:][:IPv6AddressSize], addr.AsSlice())
+}
+
+// RouterFlag returns the value of the Router Flag field.
+func (b NDPNeighborAdvert) RouterFlag() bool {
+	return b[ndpNAFlagsOffset]&ndpNARouterFlagMask != 0
+}
+
+// SetRouterFlag sets the value in the Router Flag field.
+func (b NDPNeighborAdvert) SetRouterFlag(f bool) {
+	if f {
+		b[ndpNAFlagsOffset] |= ndpNARouterFlagMask
+	} else {
+		b[ndpNAFlagsOffset] &^= ndpNARouterFlagMask
+	}
+}
+
+// SolicitedFlag returns the value of the Solicited Flag field.
+func (b NDPNeighborAdvert) SolicitedFlag() bool {
+	return b[ndpNAFlagsOffset]&ndpNASolicitedFlagMask != 0
+}
+
+// SetSolicitedFlag sets the value in the Solicited Flag field.
+func (b NDPNeighborAdvert) SetSolicitedFlag(f bool) {
+	if f {
+		b[ndpNAFlagsOffset] |= ndpNASolicitedFlagMask
+	} else {
+		b[ndpNAFlagsOffset] &^= ndpNASolicitedFlagMask
+	}
+}
+
+// OverrideFlag returns the value of the Override Flag field.
+func (b NDPNeighborAdvert) OverrideFlag() bool {
+	return b[ndpNAFlagsOffset]&ndpNAOverrideFlagMask != 0
+}
+
+// SetOverrideFlag sets the value in the Override Flag field.
+func (b NDPNeighborAdvert) SetOverrideFlag(f bool) {
+	if f {
+		b[ndpNAFlagsOffset] |= ndpNAOverrideFlagMask
+	} else {
+		b[ndpNAFlagsOffset] &^= ndpNAOverrideFlagMask
+	}
+}
+
+// Options returns an NDPOptions of the options body.
+func (b NDPNeighborAdvert) Options() NDPOptions {
+	return NDPOptions(b[ndpNAOptionsOffset:])
+}