RH_ToDestinationNode - check Routing Header Processing (to Destination Node)
Router
RH_ToDestinationNode.seq [-tooloption ...] -pkt RH_ToDestinationNode.def
-tooloption : v6eval tool option
See also RH.def
None
Tester Target Tester
(Link0) (Link1)
| | |
|-------------------------->| |
| Packet to Link0 | |
| | |
| |-------------------------->|
| | Neighbor Solicitation |
| | |
| |<--------------------------|
| | Neighbor Advertisement |
| | |
| |-------------------------->|
| | Packet from Link1 |
| | |
| | |
| |<--------------------------|
| | Packet to Link1 |
| | |
|<--------------------------| |
| Neighbor Solicitation | |
| | |
|-------------------------->| |
| Neighbor Advertisement | |
| | |
|<--------------------------| |
| Packet from Link0 | |
| | |
v v v
1. Send Packet to Link0 2. Wait Packet from Link1 or NS from Link1 3. If NS received then send NA to Link1, and wait Packet form Link1 again 4. Receive Packet from Link1 5. Send Packet to Link1 6. Wait Packet from Link0 or NS from Link0 7. If NS received then send NA to Link0, and wait Packet form Link0 again 8. Receive Packet from Link0
Network topology
(Link0) (Link1)
Tester Target Tester
Host1 ------ Router1 ------ Router2 ------ Router3 ------ Host2
Global 4 Global 2 Global 0 Global 1
Packet to Link0 is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 56
NextHeader = 43 (Routing Header)
SourceAddress = Global 4 Address (Host1)
DestinationAddress = Global 0 Address (Router3)
Routing Header
NextHeader = 59 (No Next Header)
HeaderExtLength = 6
RoutingType = 0
SegmentsLeft = 1
Address[1] = Global 4 Address (Router1)
Address[2] = Global 2 Address (Router2)
Address[3] = Global 1 Address (Host2)
Packet to Link1 is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 56
NextHeader = 43 (Routing Header)
SourceAddress = Global 1 Address (Host2)
DestinationAddress = Global 1 Address (Router3)
Routing Header
NextHeader = 59 (No Next Header)
HeaderExtLength = 6
RoutingType = 0
SegmentsLeft = 3
Address[1] = Global 0 Address (Router2)
Address[2] = Global 2 Address (Router1)
Address[3] = Global 4 Address (Host1)
Neighbor Solicitation packet's IP source Address selection may be:
- Link Local Address
- Global Address
This test IS NOT the Neighbor Discovery test, so admit both implementation.
PASS: Packet from Link1 and Packet from Link0 Received
Packet from Link1 is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 56
NextHeader = 43 (Routing Header)
SourceAddress = Global 4 Address (Host1)
DestinationAddress = Global 1 Address (Host2) <---+
|
Routing Header |
NextHeader = 59 (No Next Header) | (swapped)
HeaderExtLength = 6 |
RoutingType = 0 |
SegmentsLeft = 0 (decremented) |
Address[1] = Global 4 Address (Router1) <----+
Address[2] = Global 2 Address (Router2)
Address[3] = Global 0 Address (Router3)
Packet from Link0 is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 56
NextHeader = 43 (Routing Header)
SourceAddress = Global 1 Address (Host2)
DestinationAddress = Global 0 Address (Router2) <-+
|
Routing Header |
NextHeader = 59 (No Next Header) | (swapped)
HeaderExtLength = 6 |
RoutingType = 0 |
SegmentsLeft = 2 (decremented) |
Address[1] = Global 1 Address (Router3) |
Address[2] = Global 2 Address (Router1) |
Address[3] = Global 4 Address (Host1) <------+
RFC2460
4.4 Routing Header
The Routing header is used by an IPv6 source to list one or more intermediate nodes to be "visited" on the way to a packet's destination. This function is very similar to IPv4's Loose Source and Record Route option. The Routing header is identified by a Next Header value of 43 in the immediately preceding header, and has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. type-specific data .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Next Header 8-bit selector. Identifies the type of header
immediately following the Routing header. Uses
the same values as the IPv4 Protocol field
[RFC-1700 et seq.].
Hdr Ext Len 8-bit unsigned integer. Length of the Routing
header in 8-octet units, not including the first
8 octets.
Routing Type 8-bit identifier of a particular Routing header
variant.
Segments Left 8-bit unsigned integer. Number of route
segments remaining, i.e., number of explicitly
listed intermediate nodes still to be visited
before reaching the final destination.
type-specific data Variable-length field, of format determined by
the Routing Type, and of length such that the
complete Routing header is an integer multiple
of 8 octets long.
If, while processing a received packet, a node encounters a Routing header with an unrecognized Routing Type value, the required behavior of the node depends on the value of the Segments Left field, as follows:
If Segments Left is zero, the node must ignore the Routing header
and proceed to process the next header in the packet, whose type
is identified by the Next Header field in the Routing header.
If Segments Left is non-zero, the node must discard the packet and
send an ICMP Parameter Problem, Code 0, message to the packet's
Source Address, pointing to the unrecognized Routing Type.
If, after processing a Routing header of a received packet, an intermediate node determines that the packet is to be forwarded onto a link whose link MTU is less than the size of the packet, the node must discard the packet and send an ICMP Packet Too Big message to the packet's Source Address.
The Type 0 Routing header has the following format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type=0| Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Address[1] +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Address[2] +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . .
. . .
. . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Address[n] +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Next Header 8-bit selector. Identifies the type of header
immediately following the Routing header. Uses
the same values as the IPv4 Protocol field
[RFC-1700 et seq.].
Hdr Ext Len 8-bit unsigned integer. Length of the Routing
header in 8-octet units, not including the first
8 octets. For the Type 0 Routing header, Hdr
Ext Len is equal to two times the number of
addresses in the header.
Routing Type 0.
Segments Left 8-bit unsigned integer. Number of route
segments remaining, i.e., number of explicitly
listed intermediate nodes still to be visited
before reaching the final destination.
Reserved 32-bit reserved field. Initialized to zero for
transmission; ignored on reception.
Address[1..n] Vector of 128-bit addresses, numbered 1 to n.</B>
Multicast addresses must not appear in a Routing header of Type 0, or in the IPv6 Destination Address field of a packet carrying a Routing header of Type 0.
A Routing header is not examined or processed until it reaches the node identified in the Destination Address field of the IPv6 header. In that node, dispatching on the Next Header field of the immediately preceding header causes the Routing header module to be invoked, which, in the case of Routing Type 0, performs the following algorithm:
if Segments Left = 0 {
proceed to process the next header in the packet, whose type is
identified by the Next Header field in the Routing header
}
else if Hdr Ext Len is odd {
send an ICMP Parameter Problem, Code 0, message to the Source
Address, pointing to the Hdr Ext Len field, and discard the
packet
}
else {
compute n, the number of addresses in the Routing header, by
dividing Hdr Ext Len by 2
if Segments Left is greater than n {
send an ICMP Parameter Problem, Code 0, message to the Source
Address, pointing to the Segments Left field, and discard the
packet
}
else {
decrement Segments Left by 1;
compute i, the index of the next address to be visited in
the address vector, by subtracting Segments Left from n
if Address [i] or the IPv6 Destination Address is multicast {
discard the packet
}
else {
swap the IPv6 Destination Address and Address[i]
if the IPv6 Hop Limit is less than or equal to 1 {
send an ICMP Time Exceeded -- Hop Limit Exceeded in
Transit message to the Source Address and discard the
packet
}
else {
decrement the Hop Limit by 1
resubmit the packet to the IPv6 module for transmission
to the new destination
}
}
}
}
perldoc V6evalTool