README
¶
goIGMP
go IGMP toys
This is a little go library to allow handling of IGMP messages for different scenarios.
It was mostly designed to allow proxing IGMP messages into a docker bridge network to containers. There is a special unicast response mode which allows crafting specific IGMP responses in the case you do not want to jsut let the kernel respond. Essentailly, this allows you to control which IGMP responses come out of the docker network.
Interfaces "outside" and "inside"
The interface names are named outside and inside a little like an old Cisco PIX.
Potentially "upstream" and "downstream" would have been better names.
When there are x2 outside interfaces, the second interface is named "alternative" or "alt".
Proxy from outside to inside
ProxyOutToIn true
ProxyInToOut false
UnicastProxyInToOut true
QueryNotify false
MembershipReportFromNetwork false
MembershipReportToNetworkCh false
UnicastMembershipResponse false
Two (2) outside interfaces
Allow for x2 outside interfaces, with a channel to allow an application to signal which outside interface to use.
ProxyOutToIn true
ProxyInToOut false
UnicastProxyInToOut true
QueryNotify false
MembershipReportFromNetwork false
MembershipReportToNetworkCh false
UnicastMembershipResponse false
Full Proxy Mode
outName enp1s0
altName gre0
inName dockerbr
ProxyOutToIn true
ProxyInToOut true
UnicastProxyInToOut true
QueryNotify false
MembershipReportFromNetwork false
MembershipReportToNetworkCh false
UnicastMembershipResponse false
Client mode
Client mode setups up channels
- QueryNotifyCh struct{}
- MembershipReportToNetworkCh []membershipItem
- MembershipReportFromNetworkCh []membershipItem
type membershipItem struct {
Source netip.Addr
Group netip.Addr
}
outName enp1s0
inName dockerbr
ProxyOutToIn false
ProxyInToOut false
UnicastProxyInToOut false
QueryNotify true
MembershipReportFromNetwork true
MembershipReportToNetworkCh true
UnicastMembershipResponse true
This is an example of using the proxy from outside to inside, and then having a special application controlling the IGMP responses that leave the docker network.
Code to:
- send IGMP membership reports
- recieve IGMP membership queries
IGMP version support
The code essenially just copies the entire payload, but was tested against IGMPv3.
IGMPv2 sends the join on the multicast group in question, so this code doesn't really do that. It could be extended to support this easily enough I suppose.
IGMPv3
Internet Group Management Protocol, Version 3 https://www.rfc-editor.org/rfc/rfc3376
Message Formats
https://www.rfc-editor.org/rfc/rfc3376#section-4
IGMP messages are encapsulated in IPv4 datagrams, with an IP protocol
number of 2. Every IGMP message described in this document is sent
with an IP Time-to-Live of 1, IP Precedence of Internetwork Control
(e.g., Type of Service 0xc0), and carries an IP Router Alert option
[RFC-2113] in its IP header.
- IP protocol = 2
- TTL = 1
- IP Precedence = 0xc0
- Router alert
Router Alert
Router alert: https://www.rfc-editor.org/rfc/rfc2113
The Router Alert option has the following format:
+--------+--------+--------+--------+
|10010100|00000100| 2 octet value |
+--------+--------+--------+--------+
Type:
Copied flag: 1 (all fragments must carry the option)
Option class: 0 (control)
Option number: 20 (decimal)
Length: 4
Value: A two octet code with the following values:
0 - Router shall examine packet
1-65535 - Reserved
10010100 = 0x94
00000100 = 0x04
Type Number (hex) Message Name
----------------- ------------
0x11 Membership Query
0x22 Version 3 Membership Report
IGMPv2
https://www.rfc-editor.org/rfc/rfc2236
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1. Membership Query Message
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] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2. Version 3 Membership Report Message
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] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each Group 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 .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
GoPacket
https://github.com/google/gopacket/
https://github.com/google/gopacket/blob/master/layers/igmp.go https://github.com/google/gopacket/blob/master/layers/igmp_test.go
IGMP Query https://github.com/google/gopacket/blob/master/layers/igmp.go#L78
IGMP Membership Report https://github.com/google/gopacket/blob/master/layers/igmp.go#L162
See also https://github.com/jmylchreest/igmpqd https://github.com/individuwill/mcast/
Documentation
¶
Index ¶
- Constants
- type Config
- type IGMP
- func (i *IGMP) LayerContents() []byte
- func (i *IGMP) LayerPayload() []byte
- func (i *IGMP) LayerType() gopacket.LayerType
- func (igmp *IGMP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
- func (igmp *IGMP) SerializeToIGMPv2(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
- func (igmp *IGMP) SerializeToIGMPv3(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
- type IGMPReporter
- type IGMPv3GroupRecord
- type IGMPv3GroupRecordType
- type MembershipItem
- type TestingOptions
Constants ¶
const ( // IN = "inside" // OUT = "outside" OUT side = 1 IN side = 2 ALTOUT side = 3 OUTSTR = "outside" ALTOUTSTR = "altOutside" INSTR = "inside" OutOrAltKey int = 1 TTL ttlType = 1 GRATUITOUS ttlType = 2 QUERY ttlType = 3 IGMPHostsQuad = "224.0.0.22" IGMPHosts destIP = 22 // 224.0.0.22 QueryHost destIP = 666 // In this case we use the query source IP )
const ( IGMPv2SizeCst = 8 IGMPv3BaseSizeCst = 24 )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Config ¶
type Config struct {
InIntName string
OutIntName string
AltOutIntName string
UnicastDst string
ProxyOutToIn bool
ProxyInToOut bool
UnicastProxyInToOut bool
QueryNotify bool
MembershipReportsFromNetwork bool
MembershipReportsToNetwork bool
UnicastMembershipReports bool
SocketReadDeadLine time.Duration
ChannelSize int
Gratuitous time.Duration
QueryTime time.Duration
HackPayloadFilename string
DebugLevel int
Testing TestingOptions
}
type IGMP ¶
type IGMP struct {
layers.BaseLayer
Type layers.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
}
func (*IGMP) LayerContents ¶
func (*IGMP) LayerPayload ¶
func (*IGMP) SerializeTo ¶
func (igmp *IGMP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
SerializeTo writes the serialized form of this layer into the SerializationBuffer, implementing gopacket.SerializableLayer. See the docs for gopacket.SerializableLayer for more info.
func (*IGMP) SerializeToIGMPv2 ¶
func (igmp *IGMP) SerializeToIGMPv2(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
SerializeToIGMPv2 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
func (*IGMP) SerializeToIGMPv3 ¶
func (igmp *IGMP) SerializeToIGMPv3(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error
SerializeToIGMPv3 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 IGMPReporter ¶
type IGMPReporter struct {
IntName map[side]string
IntOutName *sync.Map
Interfaces []side
AltOutExists bool
OutsideInterfaces map[side]bool
TimerDuration map[ttlType]time.Duration
NetIF map[side]*net.Interface
NetIFIndex map[int]side
NetIP map[side]net.IP
NetAddr map[side]netip.Addr
ContMsg map[side]*ipv4.ControlMessage
QueryNotifyCh chan struct{}
MembershipReportFromNetworkCh chan []MembershipItem
MembershipReportToNetworkCh chan []MembershipItem
OutInterfaceSelectorCh chan side
WG *sync.WaitGroup
// contains filtered or unexported fields
}
func (IGMPReporter) Run ¶
func (r IGMPReporter) Run(ctx context.Context)
func (IGMPReporter) RunSelfQuery ¶
func (r IGMPReporter) RunSelfQuery()
type IGMPv3GroupRecord ¶
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
}
IGMPv3GroupRecord stores individual group records for a V3 Membership Report message.
type IGMPv3GroupRecordType ¶
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 (IGMPv3GroupRecordType) String ¶
func (i IGMPv3GroupRecordType) String() string
Source Files
Directories