FH_1stOnly - check Fragment Reassembly (1st fragment only)
Host and Router
FH_1stOnly.seq [-tooloption ...] -pkt Fragment.def
-tooloption : v6eval tool option
1. Ping to Target (create Neighbor Cache Entries, if not exist) 2. Override Neighbor Cache Entries
Tester Target
| |
|-------------------------->|
| Echo Request (1st) |
| |
| |
|<--------------------------|
| ICMP Error |
| |
| |
v v
1. Send Echo Request (1st fragment) 2. Wait ICMP Error (timeout = 60 sec) 3. Receive ICMP Error
Echo Request Data (original) is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 1032
NextHeader = 58 (ICMP)
SourceAddress = Tester Link Local Address
DestinationAddress = Target Link Local Address
ICMP Echo Request
Type = 128 (Echo Request)
Code = 0
Checksum = (auto)
Identifier = (auto)
SequenceNumber = 0
PayloadData = data repeat{0x1, 512}
data repeat{0x2, 512}
Echo Request Data (1st fragment) is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 528
NextHeader = 44 (Fragment Header)
SourceAddress = Tester Link Local Address
DestinationAddress = Target Link Local Address
Fragment Header
NextHeader = 58 (ICMP)
FragmentOffset = 0
MFlag = 1
Identification = 32bit (Automatic generation)
Payload
data = 520 octets from the head of ICMP Echo request
PASS: ICMP Error Received
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 16
NextHeader = 58 (ICMP)
SourceAddress = Target Link Local Address
Destination Address = Tester Link Local Address
ICMP Error
Type = 3 (Time Exceeded)
Code = 1 (fragment reassembly time exceeded)
Checksum = (auto)
PayloadData = (Echo Request)
RFC2460
4.5 Fragment Header
:
The following error conditions may arise when reassembling fragmented packets:
If insufficient fragments are received to complete reassembly of a
packet within 60 seconds of the reception of the first-arriving
fragment of that packet, reassembly of that packet must be
abandoned and all the fragments that have been received for that
packet must be discarded. If the first fragment (i.e., the one
with a Fragment Offset of zero) has been received, an ICMP Time
Exceeded -- Fragment Reassembly Time Exceeded message should be
sent to the source of that fragment.
SEE ALSO
perldoc V6evalTool