mirror of
https://github.com/SagerNet/sing-tun.git
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110 lines
3.5 KiB
Go
110 lines
3.5 KiB
Go
// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package header
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import "github.com/sagernet/sing-tun/internal/gtcpip"
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// NDPNeighborAdvert is an NDP Neighbor Advertisement message. It will
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// only contain the body of an ICMPv6 packet.
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//
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// See RFC 4861 section 4.4 for more details.
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type NDPNeighborAdvert []byte
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const (
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// NDPNAMinimumSize is the minimum size of a valid NDP Neighbor
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// Advertisement message (body of an ICMPv6 packet).
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NDPNAMinimumSize = 20
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// ndpNATargetAddressOffset is the start of the Target Address
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// field within an NDPNeighborAdvert.
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ndpNATargetAddressOffset = 4
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// ndpNAOptionsOffset is the start of the NDP options in an
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// NDPNeighborAdvert.
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ndpNAOptionsOffset = ndpNATargetAddressOffset + IPv6AddressSize
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// ndpNAFlagsOffset is the offset of the flags within an
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// NDPNeighborAdvert
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ndpNAFlagsOffset = 0
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// ndpNARouterFlagMask is the mask of the Router Flag field in
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// the flags byte within in an NDPNeighborAdvert.
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ndpNARouterFlagMask = (1 << 7)
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// ndpNASolicitedFlagMask is the mask of the Solicited Flag field in
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// the flags byte within in an NDPNeighborAdvert.
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ndpNASolicitedFlagMask = (1 << 6)
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// ndpNAOverrideFlagMask is the mask of the Override Flag field in
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// the flags byte within in an NDPNeighborAdvert.
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ndpNAOverrideFlagMask = (1 << 5)
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)
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// TargetAddress returns the value within the Target Address field.
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func (b NDPNeighborAdvert) TargetAddress() tcpip.Address {
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return tcpip.AddrFrom16Slice(b[ndpNATargetAddressOffset:][:IPv6AddressSize])
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}
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// SetTargetAddress sets the value within the Target Address field.
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func (b NDPNeighborAdvert) SetTargetAddress(addr tcpip.Address) {
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copy(b[ndpNATargetAddressOffset:][:IPv6AddressSize], addr.AsSlice())
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}
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// RouterFlag returns the value of the Router Flag field.
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func (b NDPNeighborAdvert) RouterFlag() bool {
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return b[ndpNAFlagsOffset]&ndpNARouterFlagMask != 0
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}
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// SetRouterFlag sets the value in the Router Flag field.
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func (b NDPNeighborAdvert) SetRouterFlag(f bool) {
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if f {
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b[ndpNAFlagsOffset] |= ndpNARouterFlagMask
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} else {
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b[ndpNAFlagsOffset] &^= ndpNARouterFlagMask
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}
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}
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// SolicitedFlag returns the value of the Solicited Flag field.
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func (b NDPNeighborAdvert) SolicitedFlag() bool {
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return b[ndpNAFlagsOffset]&ndpNASolicitedFlagMask != 0
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}
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// SetSolicitedFlag sets the value in the Solicited Flag field.
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func (b NDPNeighborAdvert) SetSolicitedFlag(f bool) {
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if f {
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b[ndpNAFlagsOffset] |= ndpNASolicitedFlagMask
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} else {
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b[ndpNAFlagsOffset] &^= ndpNASolicitedFlagMask
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}
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}
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// OverrideFlag returns the value of the Override Flag field.
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func (b NDPNeighborAdvert) OverrideFlag() bool {
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return b[ndpNAFlagsOffset]&ndpNAOverrideFlagMask != 0
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}
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// SetOverrideFlag sets the value in the Override Flag field.
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func (b NDPNeighborAdvert) SetOverrideFlag(f bool) {
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if f {
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b[ndpNAFlagsOffset] |= ndpNAOverrideFlagMask
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} else {
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b[ndpNAFlagsOffset] &^= ndpNAOverrideFlagMask
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}
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}
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// Options returns an NDPOptions of the options body.
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func (b NDPNeighborAdvert) Options() NDPOptions {
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return NDPOptions(b[ndpNAOptionsOffset:])
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}
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