2c4ae3b0a4
Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для неё не нужна. Module path github.com/sagernet/gvisor сохранён намеренно: на него опирается replace-директива суперпроекта. Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show и переносилась на новый пин копированием. SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH
539 lines
26 KiB
Go
539 lines
26 KiB
Go
// Copyright 2022 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 (
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"bytes"
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"encoding/binary"
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"fmt"
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"time"
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"github.com/sagernet/gvisor/pkg/tcpip"
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)
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const (
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// MLDv2QueryMinimumSize is the minimum size for an MLDv2 message.
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MLDv2QueryMinimumSize = 24
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mldv2QueryMaximumResponseCodeOffset = 0
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mldv2QueryResvSQRVOffset = 20
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mldv2QueryQRVMask = 0b111
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mldv2QueryQQICOffset = 21
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// mldv2QueryNumberOfSourcesOffset is the offset to the Number of Sources
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// field within MLDv2Query.
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mldv2QueryNumberOfSourcesOffset = 22
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// MLDv2ReportMinimumSize is the minimum size of an MLDv2 report.
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MLDv2ReportMinimumSize = 24
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// mldv2QuerySourcesOffset is the offset to the Sources field within
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// MLDv2Query.
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mldv2QuerySourcesOffset = 24
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)
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// MLDv2RoutersAddress is the address to send MLDv2 reports to.
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//
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// As per RFC 3810 section 5.2.14,
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//
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// Version 2 Multicast Listener Reports are sent with an IP destination
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// address of FF02:0:0:0:0:0:0:16, to which all MLDv2-capable multicast
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// routers listen (see section 11 for IANA considerations related to
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// this special destination address).
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var MLDv2RoutersAddress = tcpip.AddrFrom16([16]byte{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x16})
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// MLDv2Query is a Multicast Listener Discovery Version 2 Query message in an
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// ICMPv6 packet.
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//
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// MLDv2Query will only contain the body of an ICMPv6 packet.
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//
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// As per RFC 3810 section 5.1, MLDv2 Query messages have the following format
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// (MLDv2Query only holds the bytes after the first four bytes in the diagram
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// below):
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//
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// 0 1 2 3
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Type = 130 | Code | Checksum |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Maximum Response Code | Reserved |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Multicast Address *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Resv |S| QRV | QQIC | Number of Sources (N) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Source Address [1] *
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// | |
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// * *
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// | |
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [2] *
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// | |
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// * *
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// | |
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// +- . -+
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// . . .
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// . . .
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [N] *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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type MLDv2Query MLD
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// MaximumResponseCode returns the Maximum Response Code
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func (m MLDv2Query) MaximumResponseCode() uint16 {
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return binary.BigEndian.Uint16(m[mldv2QueryMaximumResponseCodeOffset:])
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}
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// MLDv2MaximumResponseDelay returns the Maximum Response Delay in an MLDv2
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// Maximum Response Code.
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//
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// As per RFC 3810 section 5.1.3,
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//
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// The Maximum Response Code field specifies the maximum time allowed
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// before sending a responding Report. The actual time allowed, called
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// the Maximum Response Delay, is represented in units of milliseconds,
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// and is derived from the Maximum Response Code as follows:
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//
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// If Maximum Response Code < 32768,
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// Maximum Response Delay = Maximum Response Code
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//
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// If Maximum Response Code >=32768, Maximum Response Code represents a
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// floating-point value as follows:
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// |1| exp | mant |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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//
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// Maximum Response Delay = (mant | 0x1000) << (exp+3)
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//
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// Small values of Maximum Response Delay allow MLDv2 routers to tune
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// the "leave latency" (the time between the moment the last node on a
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// link ceases to listen to a specific multicast address and the moment
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// the routing protocol is notified that there are no more listeners for
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// that address). Larger values, especially in the exponential range,
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// allow the tuning of the burstiness of MLD traffic on a link.
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func MLDv2MaximumResponseDelay(codeRaw uint16) time.Duration {
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code := time.Duration(codeRaw)
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if code < 32768 {
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return code * time.Millisecond
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}
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const mantBits = 12
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const expMask = 0b111
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exp := (code >> mantBits) & expMask
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mant := code & ((1 << mantBits) - 1)
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return (mant | 0x1000) << (exp + 3) * time.Millisecond
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}
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// MulticastAddress returns the Multicast Address.
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func (m MLDv2Query) MulticastAddress() tcpip.Address {
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// As per RFC 2710 section 3.5:
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//
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// In a Query message, the Multicast Address field is set to zero when
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// sending a General Query, and set to a specific IPv6 multicast address
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// when sending a Multicast-Address-Specific Query.
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//
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// In a Report or Done message, the Multicast Address field holds a
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// specific IPv6 multicast address to which the message sender is
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// listening or is ceasing to listen, respectively.
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return tcpip.AddrFrom16([16]byte(m[mldMulticastAddressOffset:][:IPv6AddressSize]))
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}
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// QuerierRobustnessVariable returns the querier's robustness variable.
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func (m MLDv2Query) QuerierRobustnessVariable() uint8 {
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return m[mldv2QueryResvSQRVOffset] & mldv2QueryQRVMask
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}
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// QuerierQueryInterval returns the querier's query interval.
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func (m MLDv2Query) QuerierQueryInterval() time.Duration {
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return mldv2AndIGMPv3QuerierQueryCodeToInterval(m[mldv2QueryQQICOffset])
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}
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// Sources returns an iterator over source addresses in the query.
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//
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// Returns false if the message cannot hold the expected number of sources.
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func (m MLDv2Query) Sources() (AddressIterator, bool) {
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return makeAddressIterator(
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m[mldv2QuerySourcesOffset:],
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binary.BigEndian.Uint16(m[mldv2QueryNumberOfSourcesOffset:]),
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IPv6AddressSize,
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)
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}
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// MLDv2ReportRecordType is the type of an MLDv2 multicast address record
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// found in an MLDv2 report, as per RFC 3810 section 5.2.12.
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type MLDv2ReportRecordType int
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// MLDv2 multicast address record types, as per RFC 3810 section 5.2.12.
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const (
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MLDv2ReportRecordModeIsInclude MLDv2ReportRecordType = 1
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MLDv2ReportRecordModeIsExclude MLDv2ReportRecordType = 2
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MLDv2ReportRecordChangeToIncludeMode MLDv2ReportRecordType = 3
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MLDv2ReportRecordChangeToExcludeMode MLDv2ReportRecordType = 4
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MLDv2ReportRecordAllowNewSources MLDv2ReportRecordType = 5
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MLDv2ReportRecordBlockOldSources MLDv2ReportRecordType = 6
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)
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const (
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mldv2ReportMulticastAddressRecordMinimumSize = 20
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mldv2ReportMulticastAddressRecordTypeOffset = 0
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mldv2ReportMulticastAddressRecordAuxDataLenOffset = 1
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mldv2ReportMulticastAddressRecordAuxDataLenUnits = 4
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mldv2ReportMulticastAddressRecordNumberOfSourcesOffset = 2
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mldv2ReportMulticastAddressRecordMulticastAddressOffset = 4
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mldv2ReportMulticastAddressRecordSourcesOffset = 20
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)
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// MLDv2ReportMulticastAddressRecordSerializer is an MLDv2 Multicast Address
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// Record serializer.
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//
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// As per RFC 3810 section 5.2, a Multicast Address Record has the following
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// internal format:
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//
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Record Type | Aux Data Len | Number of Sources (N) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Multicast Address *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Source Address [1] *
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// | |
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// * *
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// | |
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [2] *
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// | |
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// * *
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// | |
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// +- -+
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// . . .
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// . . .
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// . . .
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [N] *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Auxiliary Data .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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type MLDv2ReportMulticastAddressRecordSerializer struct {
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RecordType MLDv2ReportRecordType
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MulticastAddress tcpip.Address
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Sources []tcpip.Address
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}
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// Length returns the number of bytes this serializer would occupy.
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func (s *MLDv2ReportMulticastAddressRecordSerializer) Length() int {
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return mldv2ReportMulticastAddressRecordSourcesOffset + len(s.Sources)*IPv6AddressSize
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}
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func copyIPv6Address(dst []byte, src tcpip.Address) {
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if n := copy(dst, src.AsSlice()); n != IPv6AddressSize {
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panic(fmt.Sprintf("got copy(...) = %d, want = %d", n, IPv6AddressSize))
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}
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}
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// SerializeInto serializes the record into the buffer.
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//
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// Panics if the buffer does not have enough space to fit the record.
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func (s *MLDv2ReportMulticastAddressRecordSerializer) SerializeInto(b []byte) {
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b[mldv2ReportMulticastAddressRecordTypeOffset] = byte(s.RecordType)
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b[mldv2ReportMulticastAddressRecordAuxDataLenOffset] = 0
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binary.BigEndian.PutUint16(b[mldv2ReportMulticastAddressRecordNumberOfSourcesOffset:], uint16(len(s.Sources)))
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copyIPv6Address(b[mldv2ReportMulticastAddressRecordMulticastAddressOffset:], s.MulticastAddress)
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b = b[mldv2ReportMulticastAddressRecordSourcesOffset:]
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for _, source := range s.Sources {
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copyIPv6Address(b, source)
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b = b[IPv6AddressSize:]
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}
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}
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const (
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mldv2ReportReservedOffset = 0
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mldv2ReportNumberOfMulticastAddressRecordsOffset = 2
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mldv2ReportMulticastAddressRecordsOffset = 4
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)
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// MLDv2ReportSerializer is an MLD Version 2 Report serializer.
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//
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// As per RFC 3810 section 5.2,
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//
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// 0 1 2 3
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Type = 143 | Reserved | Checksum |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Reserved |Nr of Mcast Address Records (M)|
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Multicast Address Record [1] .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Multicast Address Record [2] .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | . |
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// . . .
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// | . |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Multicast Address Record [M] .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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type MLDv2ReportSerializer struct {
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Records []MLDv2ReportMulticastAddressRecordSerializer
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}
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// Length returns the number of bytes this serializer would occupy.
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func (s *MLDv2ReportSerializer) Length() int {
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ret := mldv2ReportMulticastAddressRecordsOffset
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for _, record := range s.Records {
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ret += record.Length()
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}
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return ret
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}
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// SerializeInto serializes the report into the buffer.
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//
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// Panics if the buffer does not have enough space to fit the report.
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func (s *MLDv2ReportSerializer) SerializeInto(b []byte) {
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binary.BigEndian.PutUint16(b[mldv2ReportReservedOffset:], 0)
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binary.BigEndian.PutUint16(b[mldv2ReportNumberOfMulticastAddressRecordsOffset:], uint16(len(s.Records)))
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b = b[mldv2ReportMulticastAddressRecordsOffset:]
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for _, record := range s.Records {
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len := record.Length()
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record.SerializeInto(b[:len])
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b = b[len:]
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}
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}
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// MLDv2ReportMulticastAddressRecord is an MLDv2 record.
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//
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// As per RFC 3810 section 5.2, a Multicast Address Record has the following
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// internal format:
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//
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Record Type | Aux Data Len | Number of Sources (N) |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Multicast Address *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// * *
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// | |
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// * Source Address [1] *
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// | |
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// * *
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// | |
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [2] *
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// | |
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// * *
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// | |
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// +- -+
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// . . .
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// . . .
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// . . .
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// +- -+
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// | |
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// * *
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// | |
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// * Source Address [N] *
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// | |
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// * *
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Auxiliary Data .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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type MLDv2ReportMulticastAddressRecord []byte
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// RecordType returns the type of this record.
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func (r MLDv2ReportMulticastAddressRecord) RecordType() MLDv2ReportRecordType {
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return MLDv2ReportRecordType(r[mldv2ReportMulticastAddressRecordTypeOffset])
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}
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// AuxDataLen returns the length of the auxiliary data in this record.
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func (r MLDv2ReportMulticastAddressRecord) AuxDataLen() int {
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return int(r[mldv2ReportMulticastAddressRecordAuxDataLenOffset]) * mldv2ReportMulticastAddressRecordAuxDataLenUnits
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}
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// numberOfSources returns the number of sources in this record.
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func (r MLDv2ReportMulticastAddressRecord) numberOfSources() uint16 {
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return binary.BigEndian.Uint16(r[mldv2ReportMulticastAddressRecordNumberOfSourcesOffset:])
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}
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// MulticastAddress returns the multicast address this record targets.
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func (r MLDv2ReportMulticastAddressRecord) MulticastAddress() tcpip.Address {
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return tcpip.AddrFrom16([16]byte(r[mldv2ReportMulticastAddressRecordMulticastAddressOffset:][:IPv6AddressSize]))
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}
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// Sources returns an iterator over source addresses in the query.
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//
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// Returns false if the message cannot hold the expected number of sources.
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func (r MLDv2ReportMulticastAddressRecord) Sources() (AddressIterator, bool) {
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expectedLen := int(r.numberOfSources()) * IPv6AddressSize
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b := r[mldv2ReportMulticastAddressRecordSourcesOffset:]
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if len(b) < expectedLen {
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return AddressIterator{}, false
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}
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return AddressIterator{addressSize: IPv6AddressSize, buf: bytes.NewBuffer(b[:expectedLen])}, true
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}
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// MLDv2Report is an MLDv2 Report.
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//
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// As per RFC 3810 section 5.2,
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//
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// 0 1 2 3
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Type = 143 | Reserved | Checksum |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Reserved |Nr of Mcast Address Records (M)|
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
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// . .
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// . Multicast Address Record [1] .
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// . .
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// | |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | |
|
|
// . .
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// . Multicast Address Record [2] .
|
|
// . .
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | . |
|
|
// . . .
|
|
// | . |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | |
|
|
// . .
|
|
// . Multicast Address Record [M] .
|
|
// . .
|
|
// | |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|
type MLDv2Report []byte
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|
|
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// MLDv2ReportMulticastAddressRecordIterator is an iterator over MLDv2 Multicast
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// Address Records.
|
|
type MLDv2ReportMulticastAddressRecordIterator struct {
|
|
recordsLeft uint16
|
|
buf *bytes.Buffer
|
|
}
|
|
|
|
// MLDv2ReportMulticastAddressRecordIteratorNextDisposition is the possible
|
|
// return values from MLDv2ReportMulticastAddressRecordIterator.Next.
|
|
type MLDv2ReportMulticastAddressRecordIteratorNextDisposition int
|
|
|
|
const (
|
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// MLDv2ReportMulticastAddressRecordIteratorNextOk indicates that a multicast
|
|
// address record was yielded.
|
|
MLDv2ReportMulticastAddressRecordIteratorNextOk MLDv2ReportMulticastAddressRecordIteratorNextDisposition = iota
|
|
|
|
// MLDv2ReportMulticastAddressRecordIteratorNextDone indicates that the iterator
|
|
// has been exhausted.
|
|
MLDv2ReportMulticastAddressRecordIteratorNextDone
|
|
|
|
// MLDv2ReportMulticastAddressRecordIteratorNextErrBufferTooShort indicates
|
|
// that the iterator expected another record, but the buffer ended
|
|
// prematurely.
|
|
MLDv2ReportMulticastAddressRecordIteratorNextErrBufferTooShort
|
|
)
|
|
|
|
// Next returns the next MLDv2 Multicast Address Record.
|
|
func (it *MLDv2ReportMulticastAddressRecordIterator) Next() (MLDv2ReportMulticastAddressRecord, MLDv2ReportMulticastAddressRecordIteratorNextDisposition) {
|
|
if it.recordsLeft == 0 {
|
|
return MLDv2ReportMulticastAddressRecord{}, MLDv2ReportMulticastAddressRecordIteratorNextDone
|
|
}
|
|
if it.buf.Len() < mldv2ReportMulticastAddressRecordMinimumSize {
|
|
return MLDv2ReportMulticastAddressRecord{}, MLDv2ReportMulticastAddressRecordIteratorNextErrBufferTooShort
|
|
}
|
|
|
|
hdr := MLDv2ReportMulticastAddressRecord(it.buf.Bytes())
|
|
expectedLen := mldv2ReportMulticastAddressRecordMinimumSize +
|
|
int(hdr.AuxDataLen()) + int(hdr.numberOfSources())*IPv6AddressSize
|
|
|
|
bytes := it.buf.Next(expectedLen)
|
|
if len(bytes) < expectedLen {
|
|
return MLDv2ReportMulticastAddressRecord{}, MLDv2ReportMulticastAddressRecordIteratorNextErrBufferTooShort
|
|
}
|
|
it.recordsLeft--
|
|
return MLDv2ReportMulticastAddressRecord(bytes), MLDv2ReportMulticastAddressRecordIteratorNextOk
|
|
}
|
|
|
|
// MulticastAddressRecords returns an iterator of MLDv2 Multicast Address
|
|
// Records.
|
|
func (m MLDv2Report) MulticastAddressRecords() MLDv2ReportMulticastAddressRecordIterator {
|
|
return MLDv2ReportMulticastAddressRecordIterator{
|
|
recordsLeft: binary.BigEndian.Uint16(m[mldv2ReportNumberOfMulticastAddressRecordsOffset:]),
|
|
buf: bytes.NewBuffer(m[mldv2ReportMulticastAddressRecordsOffset:]),
|
|
}
|
|
}
|