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// 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 "gvisor.dev/gvisor/pkg/tcpip"
// 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.Address(b[ndpNATargetAddressOffset:][:IPv6AddressSize])
}
// SetTargetAddress sets the value within the Target Address field.
func (b NDPNeighborAdvert) SetTargetAddress(addr tcpip.Address) {
copy(b[ndpNATargetAddressOffset:][:IPv6AddressSize], addr)
}
// 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 the options body.
func (b NDPNeighborAdvert) Options() NDPOptions {
return NDPOptions(b[ndpNAOptionsOffset:])
}
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