| // 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:]) |
| } |