ICMPv6报文超时消息
当收到TTL为0的报文时，IPv6网络设备/主机会丢弃该报文，并返回一个ICMPv6超时消息。
一、ICMPv6超时消息的格式
+0-------7-------15---------------31
| Type | Code | Checksum |
+----------------------------------
| Unused |
+---------------------------------+
| As much of invoking |
| packet as possible without |
| the ICMPv6 packet exceeding |
| the minimum IPv6 MTU |
+---------------------------------+
二、ICMPv6超时消息的格式解释
| 字段 | 长度 | 含义 |
|---|---|---|
| Type | 1字节 | 消息类型，此处值为3。 |
| Code | 1字节 |
|
| Checksum | 2字节 | 用来在ICMPv6报文中检验数据和部分IPv6首部的完整性。 |
| unused | 4字节 | 该字段对所有的code值均未使用。在报文的发送端，该字段必须被初始化为0，且在接收端，该字段应该被忽略。 |
三、ICMPv6超时消息报文示例
Frame 1: 126 bytes on wire (1008 bits), 126 bytes captured (1008 bits)
Arrival Time: Jan 1, 1970 08:00:00.097316000
Epoch Time: 0.097316000 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: 126 bytes (1008 bits)
Capture Length: 126 bytes (1008 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ipv6:icmpv6:ipv6:udp:data]
[Coloring Rule Name: ICMP errors]
[Coloring Rule String: icmp.type eq 3 || icmp.type eq 4 || icmp.type eq 5 || icmp.type eq 11 || icmpv6.type eq 1 || icmpv6.type eq 2 || icmpv6.type eq 3 || icmpv6.type eq 4]
Ethernet II, Src: 00:98:01:40:00:02 (00:98:01:40:00:02), Dst: HuaweiTe_57:28:ca (00:18:82:57:28:ca)
Destination: HuaweiTe_57:28:ca (00:18:82:57:28:ca)
Address: HuaweiTe_57:28:ca (00:18:82:57:28:ca)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
Source: 00:98:01:40:00:02 (00:98:01:40:00:02)
Address: 00:98:01:40:00:02 (00:98:01:40:00:02)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
Type: IPv6 (0x86dd)
Trailer: b4aa7e68
Internet Protocol Version 6, Src: 1::1 (1::1), Dst: 1::2 (1::2)
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: 68
Next header: ICMPv6 (0x3a)
Hop limit: 64
Source: 1::1 (1::1)
Destination: 1::2 (1::2)
Internet Control Message Protocol v6
Type: Time Exceeded (3)
Code: 0 (hop limit exceeded in transit)
Checksum: 0x8b8c [correct]
Reserved: 00000000
Internet Protocol Version 6, Src: 1::2 (1::2), Dst: 2::2 (2::2)
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: 20
Next header: UDP (0x11)
Hop limit: 1
Source: 1::2 (1::2)
Destination: 2::2 (2::2)
User Datagram Protocol, Src Port: 30138 (30138), Dst Port: traceroute (33434)
Source port: 30138 (30138)
Destination port: traceroute (33434)
Length: 20
Checksum: 0x0765 [validation disabled]
[Good Checksum: False]
[Bad Checksum: False]
Data (12 bytes)
Data: 000100000000000500000000
[Length: 12]
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