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|
// Copyright 2022 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 (
"bytes"
"encoding/binary"
"fmt"
"time"
"gvisor.dev/gvisor/pkg/tcpip"
)
var (
// IGMPv3RoutersAddress is the address to send IGMPv3 reports to.
//
// As per RFC 3376 section 4.2.14,
//
// Version 3 Reports are sent with an IP destination address of
// 224.0.0.22, to which all IGMPv3-capable multicast routers listen.
IGMPv3RoutersAddress = tcpip.AddrFrom4([4]byte{0xe0, 0x00, 0x00, 0x16})
)
const (
// IGMPv3QueryMinimumSize is the mimum size of a valid IGMPv3 query,
// as per RFC 3376 section 4.1.
IGMPv3QueryMinimumSize = 12
igmpv3QueryMaxRespCodeOffset = 1
igmpv3QueryGroupAddressOffset = 4
igmpv3QueryResvSQRVOffset = 8
igmpv3QueryQRVMask = 0b111
igmpv3QueryQQICOffset = 9
igmpv3QueryNumberOfSourcesOffset = 10
igmpv3QuerySourcesOffset = 12
)
// IGMPv3Query is an IGMPv3 query message.
//
// As per RFC 3376 section 4.1,
//
// 0 1 2 3
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type = 0x11 | Max Resp Code | Checksum |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Group Address |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Resv |S| QRV | QQIC | Number of Sources (N) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Source Address [1] |
// +- -+
// | Source Address [2] |
// +- . -+
// . . .
// . . .
// +- -+
// | Source Address [N] |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
type IGMPv3Query IGMP
// MaximumResponseCode returns the Maximum Response Code.
func (i IGMPv3Query) MaximumResponseCode() uint8 {
return i[igmpv3QueryMaxRespCodeOffset]
}
// IGMPv3MaximumResponseDelay returns the Maximum Response Delay in an IGMPv3
// Maximum Response Code.
//
// As per RFC 3376 section 4.1.1,
//
// The Max Resp Code field specifies the maximum time allowed before
// sending a responding report. The actual time allowed, called the Max
// Resp Time, is represented in units of 1/10 second and is derived from
// the Max Resp Code as follows:
//
// If Max Resp Code < 128, Max Resp Time = Max Resp Code
//
// If Max Resp Code >= 128, Max Resp Code represents a floating-point
// value as follows:
//
// 0 1 2 3 4 5 6 7
// +-+-+-+-+-+-+-+-+
// |1| exp | mant |
// +-+-+-+-+-+-+-+-+
//
// Max Resp Time = (mant | 0x10) << (exp + 3)
//
// Small values of Max Resp Time allow IGMPv3 routers to tune the "leave
// latency" (the time between the moment the last host leaves a group
// and the moment the routing protocol is notified that there are no
// more members). Larger values, especially in the exponential range,
// allow tuning of the burstiness of IGMP traffic on a network.
func IGMPv3MaximumResponseDelay(codeRaw uint8) time.Duration {
code := uint16(codeRaw)
if code < 128 {
return DecisecondToDuration(code)
}
const mantBits = 4
const expMask = 0b111
exp := (code >> mantBits) & expMask
mant := code & ((1 << mantBits) - 1)
return DecisecondToDuration((mant | 0x10) << (exp + 3))
}
// GroupAddress returns the group address.
func (i IGMPv3Query) GroupAddress() tcpip.Address {
return tcpip.AddrFrom4([4]byte(i[igmpv3QueryGroupAddressOffset:][:IPv4AddressSize]))
}
// QuerierRobustnessVariable returns the querier's robustness variable.
func (i IGMPv3Query) QuerierRobustnessVariable() uint8 {
return i[igmpv3QueryResvSQRVOffset] & igmpv3QueryQRVMask
}
// QuerierQueryInterval returns the querier's query interval.
func (i IGMPv3Query) QuerierQueryInterval() time.Duration {
return mldv2AndIGMPv3QuerierQueryCodeToInterval(i[igmpv3QueryQQICOffset])
}
// Sources returns an iterator over source addresses in the query.
//
// Returns false if the message cannot hold the expected number of sources.
func (i IGMPv3Query) Sources() (AddressIterator, bool) {
return makeAddressIterator(
i[igmpv3QuerySourcesOffset:],
binary.BigEndian.Uint16(i[igmpv3QueryNumberOfSourcesOffset:]),
IPv4AddressSize,
)
}
// IGMPv3ReportRecordType is the type of an IGMPv3 multicast address record
// found in an IGMPv3 report, as per RFC 3810 section 5.2.12.
type IGMPv3ReportRecordType int
// IGMPv3 multicast address record types, as per RFC 3810 section 5.2.12.
const (
IGMPv3ReportRecordModeIsInclude IGMPv3ReportRecordType = 1
IGMPv3ReportRecordModeIsExclude IGMPv3ReportRecordType = 2
IGMPv3ReportRecordChangeToIncludeMode IGMPv3ReportRecordType = 3
IGMPv3ReportRecordChangeToExcludeMode IGMPv3ReportRecordType = 4
IGMPv3ReportRecordAllowNewSources IGMPv3ReportRecordType = 5
IGMPv3ReportRecordBlockOldSources IGMPv3ReportRecordType = 6
)
const (
igmpv3ReportGroupAddressRecordMinimumSize = 8
igmpv3ReportGroupAddressRecordTypeOffset = 0
igmpv3ReportGroupAddressRecordAuxDataLenOffset = 1
igmpv3ReportGroupAddressRecordAuxDataLenUnits = 4
igmpv3ReportGroupAddressRecordNumberOfSourcesOffset = 2
igmpv3ReportGroupAddressRecordGroupAddressOffset = 4
igmpv3ReportGroupAddressRecordSourcesOffset = 8
)
// IGMPv3ReportGroupAddressRecordSerializer is an IGMPv3 Multicast Address
// Record serializer.
//
// As per RFC 3810 section 5.2, a Multicast Address Record has the following
// internal format:
//
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Record Type | Aux Data Len | Number of Sources (N) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// * *
// | |
// * Multicast Address *
// | |
// * *
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// * *
// | |
// * Source Address [1] *
// | |
// * *
// | |
// +- -+
// | |
// * *
// | |
// * Source Address [2] *
// | |
// * *
// | |
// +- -+
// . . .
// . . .
// . . .
// +- -+
// | |
// * *
// | |
// * Source Address [N] *
// | |
// * *
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Auxiliary Data .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
type IGMPv3ReportGroupAddressRecordSerializer struct {
RecordType IGMPv3ReportRecordType
GroupAddress tcpip.Address
Sources []tcpip.Address
}
// Length returns the number of bytes this serializer would occupy.
func (s *IGMPv3ReportGroupAddressRecordSerializer) Length() int {
return igmpv3ReportGroupAddressRecordSourcesOffset + len(s.Sources)*IPv4AddressSize
}
func copyIPv4Address(dst []byte, src tcpip.Address) {
srcBytes := src.As4()
if n := copy(dst, srcBytes[:]); n != IPv4AddressSize {
panic(fmt.Sprintf("got copy(...) = %d, want = %d", n, IPv4AddressSize))
}
}
// SerializeInto serializes the record into the buffer.
//
// Panics if the buffer does not have enough space to fit the record.
func (s *IGMPv3ReportGroupAddressRecordSerializer) SerializeInto(b []byte) {
b[igmpv3ReportGroupAddressRecordTypeOffset] = byte(s.RecordType)
b[igmpv3ReportGroupAddressRecordAuxDataLenOffset] = 0
binary.BigEndian.PutUint16(b[igmpv3ReportGroupAddressRecordNumberOfSourcesOffset:], uint16(len(s.Sources)))
copyIPv4Address(b[igmpv3ReportGroupAddressRecordGroupAddressOffset:], s.GroupAddress)
b = b[igmpv3ReportGroupAddressRecordSourcesOffset:]
for _, source := range s.Sources {
copyIPv4Address(b, source)
b = b[IPv4AddressSize:]
}
}
const (
igmpv3ReportTypeOffset = 0
igmpv3ReportReserved1Offset = 1
igmpv3ReportReserved2Offset = 4
igmpv3ReportNumberOfGroupAddressRecordsOffset = 6
igmpv3ReportGroupAddressRecordsOffset = 8
)
// IGMPv3ReportSerializer is an MLD Version 2 Report serializer.
//
// As per RFC 3810 section 5.2,
//
// 0 1 2 3
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type = 143 | Reserved | Checksum |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Reserved |Nr of Mcast Address Records (M)|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [1] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [2] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | . |
// . . .
// | . |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [M] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
type IGMPv3ReportSerializer struct {
Records []IGMPv3ReportGroupAddressRecordSerializer
}
// Length returns the number of bytes this serializer would occupy.
func (s *IGMPv3ReportSerializer) Length() int {
ret := igmpv3ReportGroupAddressRecordsOffset
for _, record := range s.Records {
ret += record.Length()
}
return ret
}
// SerializeInto serializes the report into the buffer.
//
// Panics if the buffer does not have enough space to fit the report.
func (s *IGMPv3ReportSerializer) SerializeInto(b []byte) {
b[igmpv3ReportTypeOffset] = byte(IGMPv3MembershipReport)
b[igmpv3ReportReserved1Offset] = 0
binary.BigEndian.PutUint16(b[igmpv3ReportReserved2Offset:], 0)
binary.BigEndian.PutUint16(b[igmpv3ReportNumberOfGroupAddressRecordsOffset:], uint16(len(s.Records)))
recordsBytes := b[igmpv3ReportGroupAddressRecordsOffset:]
for _, record := range s.Records {
len := record.Length()
record.SerializeInto(recordsBytes[:len])
recordsBytes = recordsBytes[len:]
}
binary.BigEndian.PutUint16(b[igmpChecksumOffset:], IGMPCalculateChecksum(b))
}
// IGMPv3ReportGroupAddressRecord is an IGMPv3 record.
//
// As per RFC 3810 section 5.2, a Multicast Address Record has the following
// internal format:
//
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Record Type | Aux Data Len | Number of Sources (N) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// * *
// | |
// * Multicast Address *
// | |
// * *
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// * *
// | |
// * Source Address [1] *
// | |
// * *
// | |
// +- -+
// | |
// * *
// | |
// * Source Address [2] *
// | |
// * *
// | |
// +- -+
// . . .
// . . .
// . . .
// +- -+
// | |
// * *
// | |
// * Source Address [N] *
// | |
// * *
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Auxiliary Data .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
type IGMPv3ReportGroupAddressRecord []byte
// RecordType returns the type of this record.
func (r IGMPv3ReportGroupAddressRecord) RecordType() IGMPv3ReportRecordType {
return IGMPv3ReportRecordType(r[igmpv3ReportGroupAddressRecordTypeOffset])
}
// AuxDataLen returns the length of the auxiliary data in this record.
func (r IGMPv3ReportGroupAddressRecord) AuxDataLen() int {
return int(r[igmpv3ReportGroupAddressRecordAuxDataLenOffset]) * igmpv3ReportGroupAddressRecordAuxDataLenUnits
}
// numberOfSources returns the number of sources in this record.
func (r IGMPv3ReportGroupAddressRecord) numberOfSources() uint16 {
return binary.BigEndian.Uint16(r[igmpv3ReportGroupAddressRecordNumberOfSourcesOffset:])
}
// GroupAddress returns the multicast address this record targets.
func (r IGMPv3ReportGroupAddressRecord) GroupAddress() tcpip.Address {
return tcpip.AddrFrom4([4]byte(r[igmpv3ReportGroupAddressRecordGroupAddressOffset:][:IPv4AddressSize]))
}
// Sources returns an iterator over source addresses in the query.
//
// Returns false if the message cannot hold the expected number of sources.
func (r IGMPv3ReportGroupAddressRecord) Sources() (AddressIterator, bool) {
expectedLen := int(r.numberOfSources()) * IPv4AddressSize
b := r[igmpv3ReportGroupAddressRecordSourcesOffset:]
if len(b) < expectedLen {
return AddressIterator{}, false
}
return AddressIterator{addressSize: IPv4AddressSize, buf: bytes.NewBuffer(b[:expectedLen])}, true
}
// IGMPv3Report is an IGMPv3 Report.
//
// As per RFC 3810 section 5.2,
//
// 0 1 2 3
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type = 143 | Reserved | Checksum |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Reserved |Nr of Mcast Address Records (M)|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [1] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [2] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | . |
// . . .
// | . |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// . .
// . Multicast Address Record [M] .
// . .
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
type IGMPv3Report []byte
// Checksum returns the checksum.
func (i IGMPv3Report) Checksum() uint16 {
return binary.BigEndian.Uint16(i[igmpChecksumOffset:])
}
// IGMPv3ReportGroupAddressRecordIterator is an iterator over IGMPv3 Multicast
// Address Records.
type IGMPv3ReportGroupAddressRecordIterator struct {
recordsLeft uint16
buf *bytes.Buffer
}
// IGMPv3ReportGroupAddressRecordIteratorNextDisposition is the possible
// return values from IGMPv3ReportGroupAddressRecordIterator.Next.
type IGMPv3ReportGroupAddressRecordIteratorNextDisposition int
const (
// IGMPv3ReportGroupAddressRecordIteratorNextOk indicates that a multicast
// address record was yielded.
IGMPv3ReportGroupAddressRecordIteratorNextOk IGMPv3ReportGroupAddressRecordIteratorNextDisposition = iota
// IGMPv3ReportGroupAddressRecordIteratorNextDone indicates that the iterator
// has been exhausted.
IGMPv3ReportGroupAddressRecordIteratorNextDone
// IGMPv3ReportGroupAddressRecordIteratorNextErrBufferTooShort indicates
// that the iterator expected another record, but the buffer ended
// prematurely.
IGMPv3ReportGroupAddressRecordIteratorNextErrBufferTooShort
)
// Next returns the next IGMPv3 Multicast Address Record.
func (it *IGMPv3ReportGroupAddressRecordIterator) Next() (IGMPv3ReportGroupAddressRecord, IGMPv3ReportGroupAddressRecordIteratorNextDisposition) {
if it.recordsLeft == 0 {
return IGMPv3ReportGroupAddressRecord{}, IGMPv3ReportGroupAddressRecordIteratorNextDone
}
if it.buf.Len() < igmpv3ReportGroupAddressRecordMinimumSize {
return IGMPv3ReportGroupAddressRecord{}, IGMPv3ReportGroupAddressRecordIteratorNextErrBufferTooShort
}
hdr := IGMPv3ReportGroupAddressRecord(it.buf.Bytes())
expectedLen := igmpv3ReportGroupAddressRecordMinimumSize +
int(hdr.AuxDataLen()) + int(hdr.numberOfSources())*IPv4AddressSize
bytes := it.buf.Next(expectedLen)
if len(bytes) < expectedLen {
return IGMPv3ReportGroupAddressRecord{}, IGMPv3ReportGroupAddressRecordIteratorNextErrBufferTooShort
}
it.recordsLeft--
return IGMPv3ReportGroupAddressRecord(bytes), IGMPv3ReportGroupAddressRecordIteratorNextOk
}
// GroupAddressRecords returns an iterator of IGMPv3 Multicast Address
// Records.
func (i IGMPv3Report) GroupAddressRecords() IGMPv3ReportGroupAddressRecordIterator {
return IGMPv3ReportGroupAddressRecordIterator{
recordsLeft: binary.BigEndian.Uint16(i[igmpv3ReportNumberOfGroupAddressRecordsOffset:]),
buf: bytes.NewBuffer(i[igmpv3ReportGroupAddressRecordsOffset:]),
}
}
|
