MLDv2成员报告
MLDv2成员报告消息是主机向组播路由器发送的报告消息，用于申请加入某个组播组或者应答查询消息。
一、MLDv2成员报告消息报文格式
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] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
二、MLDv2成员报告消息字段解释
| 字段 | 长度 | 描述 |
|---|---|---|
| Type | 1字节 | 消息类型，该字段取值为143。 |
| Reserved | 1字节 | 发送时此字段设置为0，接收时不处理此字段。 |
| Checksum | 2字节 | 标准的ICMPv6校验和，覆盖所有MLD消息以及IPv6首部区域中的伪首部。在计算校验和时，此字段以零计算。发送报文时必须计算校验和并将结果写入此字段。接收报文时首先验证校验和，然后才处理报文。 |
| Reserved | 2字节 | 保留字段。发送时此字段设置为0，接收时不处理此字段。 |
| Number of Multicast Address Record | 2字节 | 组播地址记录的个数。 |
| Multicast Address Record (i) | 变长 |
组播地址记录，表示主机在接口上侦听到的每个组播地址信息，包括记录类型、组播地址、源地址等。（i＝1,2,…,m, m表示组播地址记录的个数） |
三、组播地址记录字段报文格式
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Record Type | Aux Data Len | Number of Sources (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
* *
| |
* Multicast Address *
| |
* *
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
* *
| |
* Source Address [1] *
| |
* *
| |
+- -+
| |
* *
| |
* Source Address [2] *
| |
* *
| |
+- -+
. . .
. . .
. . .
+- -+
| |
* *
| |
* Source Address [N] *
| |
* *
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Auxiliary Data .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
四、组播地址记录字段报文字段解释
| 字段 | 长度 | 说明 |
|---|---|---|
| Record Type | 1字节 | 记录类型：
|
| Aux Data Len | 1字节 | 在组播地址Record中附加Auxiliary Data的长度。 |
| Number of Sources | 2字节 | 本记录中包含的源地址数量。 |
| Multicast Address | 16字节 | 组地址。 |
| Source Address | 16字节 | 组播源地址。 |
| Auxiliary Data | 变长 | 组播地址Record的附加信息。 |
五、MLDv2成员报告消息报文示例
Frame 1: 90 bytes on wire (720 bits), 90 bytes captured (720 bits) on interface 0
Interface id: 0 (unknown)
Encapsulation type: Ethernet (1)
Arrival Time: Mar 17, 2015 14:04:56.292869000
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1426572296.292869000 seconds
[Time delta from previous captured frame: 0.000000000 seconds]
[Time delta from previous displayed frame: 0.000000000 seconds]
[Time since reference or first frame: 0.000000000 seconds]
Frame Number: 1
Frame Length: 90 bytes (720 bits)
Capture Length: 90 bytes (720 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ipv6:ipv6.nxt:ipv6.hop_opt:icmpv6]
[Coloring Rule Name: ICMP]
[Coloring Rule String: icmp || icmpv6]
Ethernet II, Src: 40:f2:e9:2e:b2:5a (40:f2:e9:2e:b2:5a), Dst: IPv6mcast_16 (33:33:00:00:00:16)
Destination: IPv6mcast_16 (33:33:00:00:00:16)
Address: IPv6mcast_16 (33:33:00:00:00:16)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
Source: 40:f2:e9:2e:b2:5a (40:f2:e9:2e:b2:5a)
Address: 40:f2:e9:2e:b2:5a (40:f2:e9:2e:b2:5a)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: fe80::2169:aab:6939:3152 (fe80::2169:aab:6939:3152), Dst: ff02::16 (ff02::16)
0110 .... = Version: 6
[0110 .... = This field makes the filter "ip.version == 6" possible: 6]
.... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
.... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
.... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
.... .... ...0 .... .... .... .... .... = ECN-CE: Not set
.... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
Payload length: 36
Next header: IPv6 hop-by-hop option (0)
Hop limit: 1
Source: fe80::2169:aab:6939:3152 (fe80::2169:aab:6939:3152)
Destination: ff02::16 (ff02::16)
[Source GeoIP: Unknown]
[Destination GeoIP: Unknown]
Hop-by-Hop Option
Next header: ICMPv6 (58)
Length: 0 (8 bytes)
IPv6 Option (Router Alert)
Type: Router Alert (5)
Length: 2
Router Alert: MLD (0)
IPv6 Option (PadN)
Type: PadN (1)
Length: 0
PadN: <MISSING>
Internet Control Message Protocol v6
Type: Multicast Listener Report Message v2 (143)
Code: 0
Checksum: 0xaa5f [correct]
Reserved: 0000
Number of Multicast Address Records: 1
Multicast Address Record Changed to include: ff02::c
Record Type: Changed to include (3)
Aux Data Len: 0
Number of Sources: 0
Multicast Address: ff02::c (ff02::c)
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