diff options
Diffstat (limited to 'vendor/github.com/google/gopacket/layers/igmp.go')
| -rw-r--r-- | vendor/github.com/google/gopacket/layers/igmp.go | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/vendor/github.com/google/gopacket/layers/igmp.go b/vendor/github.com/google/gopacket/layers/igmp.go new file mode 100644 index 0000000..d008415 --- /dev/null +++ b/vendor/github.com/google/gopacket/layers/igmp.go @@ -0,0 +1,355 @@ +// Copyright 2012 Google, Inc. All rights reserved. +// Copyright 2009-2011 Andreas Krennmair. All rights reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the LICENSE file in the root of the source +// tree. + +package layers + +import ( + "encoding/binary" + "errors" + "net" + "time" + + "github.com/google/gopacket" +) + +type IGMPType uint8 + +const ( + IGMPMembershipQuery IGMPType = 0x11 // General or group specific query + IGMPMembershipReportV1 IGMPType = 0x12 // Version 1 Membership Report + IGMPMembershipReportV2 IGMPType = 0x16 // Version 2 Membership Report + IGMPLeaveGroup IGMPType = 0x17 // Leave Group + IGMPMembershipReportV3 IGMPType = 0x22 // Version 3 Membership Report +) + +// String conversions for IGMP message types +func (i IGMPType) String() string { + switch i { + case IGMPMembershipQuery: + return "IGMP Membership Query" + case IGMPMembershipReportV1: + return "IGMPv1 Membership Report" + case IGMPMembershipReportV2: + return "IGMPv2 Membership Report" + case IGMPMembershipReportV3: + return "IGMPv3 Membership Report" + case IGMPLeaveGroup: + return "Leave Group" + default: + return "" + } +} + +type IGMPv3GroupRecordType uint8 + +const ( + IGMPIsIn IGMPv3GroupRecordType = 0x01 // Type MODE_IS_INCLUDE, source addresses x + IGMPIsEx IGMPv3GroupRecordType = 0x02 // Type MODE_IS_EXCLUDE, source addresses x + IGMPToIn IGMPv3GroupRecordType = 0x03 // Type CHANGE_TO_INCLUDE_MODE, source addresses x + IGMPToEx IGMPv3GroupRecordType = 0x04 // Type CHANGE_TO_EXCLUDE_MODE, source addresses x + IGMPAllow IGMPv3GroupRecordType = 0x05 // Type ALLOW_NEW_SOURCES, source addresses x + IGMPBlock IGMPv3GroupRecordType = 0x06 // Type BLOCK_OLD_SOURCES, source addresses x +) + +func (i IGMPv3GroupRecordType) String() string { + switch i { + case IGMPIsIn: + return "MODE_IS_INCLUDE" + case IGMPIsEx: + return "MODE_IS_EXCLUDE" + case IGMPToIn: + return "CHANGE_TO_INCLUDE_MODE" + case IGMPToEx: + return "CHANGE_TO_EXCLUDE_MODE" + case IGMPAllow: + return "ALLOW_NEW_SOURCES" + case IGMPBlock: + return "BLOCK_OLD_SOURCES" + default: + return "" + } +} + +// IGMP represents an IGMPv3 message. +type IGMP struct { + BaseLayer + Type IGMPType + MaxResponseTime time.Duration + Checksum uint16 + GroupAddress net.IP + SupressRouterProcessing bool + RobustnessValue uint8 + IntervalTime time.Duration + SourceAddresses []net.IP + NumberOfGroupRecords uint16 + NumberOfSources uint16 + GroupRecords []IGMPv3GroupRecord + Version uint8 // IGMP protocol version +} + +// IGMPv1or2 stores header details for an IGMPv1 or IGMPv2 packet. +// +// 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 | Max Resp Time | Checksum | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Group Address | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +type IGMPv1or2 struct { + BaseLayer + Type IGMPType // IGMP message type + MaxResponseTime time.Duration // meaningful only in Membership Query messages + Checksum uint16 // 16-bit checksum of entire ip payload + GroupAddress net.IP // either 0 or an IP multicast address + Version uint8 +} + +// decodeResponse dissects IGMPv1 or IGMPv2 packet. +func (i *IGMPv1or2) decodeResponse(data []byte) error { + if len(data) < 8 { + return errors.New("IGMP packet too small") + } + + i.MaxResponseTime = igmpTimeDecode(data[1]) + i.Checksum = binary.BigEndian.Uint16(data[2:4]) + i.GroupAddress = net.IP(data[4:8]) + + return nil +} + +// 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 = 0x22 | Reserved | Checksum | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Reserved | Number of Group Records (M) | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | | +// . Group Record [1] . +// | | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | | +// . Group Record [2] . +// | | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | | +// . Group Record [M] . +// | | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Record Type | Aux Data Len | Number of Sources (N) | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Multicast Address | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Source Address [1] | +// +- -+ +// | Source Address [2] | +// +- -+ +// | Source Address [N] | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | | +// . Auxiliary Data . +// | | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +// IGMPv3GroupRecord stores individual group records for a V3 Membership Report message. +type IGMPv3GroupRecord struct { + Type IGMPv3GroupRecordType + AuxDataLen uint8 // this should always be 0 as per IGMPv3 spec. + NumberOfSources uint16 + MulticastAddress net.IP + SourceAddresses []net.IP + AuxData uint32 // NOT USED +} + +func (i *IGMP) decodeIGMPv3MembershipReport(data []byte) error { + if len(data) < 8 { + return errors.New("IGMPv3 Membership Report too small #1") + } + + i.Checksum = binary.BigEndian.Uint16(data[2:4]) + i.NumberOfGroupRecords = binary.BigEndian.Uint16(data[6:8]) + + recordOffset := 8 + for j := 0; j < int(i.NumberOfGroupRecords); j++ { + if len(data) < recordOffset+8 { + return errors.New("IGMPv3 Membership Report too small #2") + } + + var gr IGMPv3GroupRecord + gr.Type = IGMPv3GroupRecordType(data[recordOffset]) + gr.AuxDataLen = data[recordOffset+1] + gr.NumberOfSources = binary.BigEndian.Uint16(data[recordOffset+2 : recordOffset+4]) + gr.MulticastAddress = net.IP(data[recordOffset+4 : recordOffset+8]) + + if len(data) < recordOffset+8+int(gr.NumberOfSources)*4 { + return errors.New("IGMPv3 Membership Report too small #3") + } + + // append source address records. + for i := 0; i < int(gr.NumberOfSources); i++ { + sourceAddr := net.IP(data[recordOffset+8+i*4 : recordOffset+12+i*4]) + gr.SourceAddresses = append(gr.SourceAddresses, sourceAddr) + } + + i.GroupRecords = append(i.GroupRecords, gr) + recordOffset += 8 + 4*int(gr.NumberOfSources) + } + return nil +} + +// 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] | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// +// decodeIGMPv3MembershipQuery parses the IGMPv3 message of type 0x11 +func (i *IGMP) decodeIGMPv3MembershipQuery(data []byte) error { + if len(data) < 12 { + return errors.New("IGMPv3 Membership Query too small #1") + } + + i.MaxResponseTime = igmpTimeDecode(data[1]) + i.Checksum = binary.BigEndian.Uint16(data[2:4]) + i.SupressRouterProcessing = data[8]&0x8 != 0 + i.GroupAddress = net.IP(data[4:8]) + i.RobustnessValue = data[8] & 0x7 + i.IntervalTime = igmpTimeDecode(data[9]) + i.NumberOfSources = binary.BigEndian.Uint16(data[10:12]) + + if len(data) < 12+int(i.NumberOfSources)*4 { + return errors.New("IGMPv3 Membership Query too small #2") + } + + for j := 0; j < int(i.NumberOfSources); j++ { + i.SourceAddresses = append(i.SourceAddresses, net.IP(data[12+j*4:16+j*4])) + } + + return nil +} + +// igmpTimeDecode decodes the duration created by the given byte, using the +// algorithm in http://www.rfc-base.org/txt/rfc-3376.txt section 4.1.1. +func igmpTimeDecode(t uint8) time.Duration { + if t&0x80 == 0 { + return time.Millisecond * 100 * time.Duration(t) + } + mant := (t & 0x70) >> 4 + exp := t & 0x0F + return time.Millisecond * 100 * time.Duration((mant|0x10)<<(exp+3)) +} + +// LayerType returns LayerTypeIGMP for the V1,2,3 message protocol formats. +func (i *IGMP) LayerType() gopacket.LayerType { return LayerTypeIGMP } +func (i *IGMPv1or2) LayerType() gopacket.LayerType { return LayerTypeIGMP } + +func (i *IGMPv1or2) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { + if len(data) < 8 { + return errors.New("IGMP Packet too small") + } + + i.Type = IGMPType(data[0]) + i.MaxResponseTime = igmpTimeDecode(data[1]) + i.Checksum = binary.BigEndian.Uint16(data[2:4]) + i.GroupAddress = net.IP(data[4:8]) + + return nil +} + +func (i *IGMPv1or2) NextLayerType() gopacket.LayerType { + return gopacket.LayerTypeZero +} + +func (i *IGMPv1or2) CanDecode() gopacket.LayerClass { + return LayerTypeIGMP +} + +// DecodeFromBytes decodes the given bytes into this layer. +func (i *IGMP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { + if len(data) < 1 { + return errors.New("IGMP packet is too small") + } + + // common IGMP header values between versions 1..3 of IGMP specification.. + i.Type = IGMPType(data[0]) + + switch i.Type { + case IGMPMembershipQuery: + i.decodeIGMPv3MembershipQuery(data) + case IGMPMembershipReportV3: + i.decodeIGMPv3MembershipReport(data) + default: + return errors.New("unsupported IGMP type") + } + + return nil +} + +// CanDecode returns the set of layer types that this DecodingLayer can decode. +func (i *IGMP) CanDecode() gopacket.LayerClass { + return LayerTypeIGMP +} + +// NextLayerType returns the layer type contained by this DecodingLayer. +func (i *IGMP) NextLayerType() gopacket.LayerType { + return gopacket.LayerTypeZero +} + +// decodeIGMP will parse IGMP v1,2 or 3 protocols. Checks against the +// IGMP type are performed against byte[0], logic then iniitalizes and +// passes the appropriate struct (IGMP or IGMPv1or2) to +// decodingLayerDecoder. +func decodeIGMP(data []byte, p gopacket.PacketBuilder) error { + if len(data) < 1 { + return errors.New("IGMP packet is too small") + } + + // byte 0 contains IGMP message type. + switch IGMPType(data[0]) { + case IGMPMembershipQuery: + // IGMPv3 Membership Query payload is >= 12 + if len(data) >= 12 { + i := &IGMP{Version: 3} + return decodingLayerDecoder(i, data, p) + } else if len(data) == 8 { + i := &IGMPv1or2{} + if data[1] == 0x00 { + i.Version = 1 // IGMPv1 has a query length of 8 and MaxResp = 0 + } else { + i.Version = 2 // IGMPv2 has a query length of 8 and MaxResp != 0 + } + + return decodingLayerDecoder(i, data, p) + } + case IGMPMembershipReportV3: + i := &IGMP{Version: 3} + return decodingLayerDecoder(i, data, p) + case IGMPMembershipReportV1: + i := &IGMPv1or2{Version: 1} + return decodingLayerDecoder(i, data, p) + case IGMPLeaveGroup, IGMPMembershipReportV2: + // leave group and Query Report v2 used in IGMPv2 only. + i := &IGMPv1or2{Version: 2} + return decodingLayerDecoder(i, data, p) + default: + } + + return errors.New("Unable to determine IGMP type.") +} |