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.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
.. (c) OPNFV, Intel Corporation and others.
.. OPNFV SAMPLEVNF Documentation design file.
===================================
SampleVNF Highlevel Desing
===================================
vFW - Design
=============
Requirements
-----------------
Following are the design requierments of the vFW.
- The firewall will examine packets and verify that they are appropriate for the
current state of the connection. Inappropriate packets will be discarded, and
counter(s) incremented.
- Support both IPv4 and IPv6 traffic type for TCP/UDP/ICMP.
- All packet inspection features like firewall, synproxy, connection tracker
in this component may be turned off or on through CLI commands
- The Static filtering is done thorugh ACL using DPDK libraries. The rules
can be added/modified through CLI commands.
- Multiple instance of the vFW Pipeline running on multipe cores should be
supported for scaling the performance scaling.
- Should follow the DPDK IP pipeline framework
- Sould use the DPDK libraries and functionalities for better performance
- The memory should be allocated in Hugepages using DPDK RTE calls for better
performance.
High Level Design
=================
The Firewall performs basic filtering for malformed packets and dynamic packet
filtering incoming packets using the connection tracker library.
The connection data will be stored using a DPDK hash table. There will be one
entry in the hash table for each connection. The hash key will be based on
source address/port,destination address/port, and protocol of a packet. The
hash key will be processed to allow a single entry to be used, regardless of
which direction the packet is flowing (thus changing source and destination).
The ACL is implemented as libray stattically linked to vFW, which is used for
used for rule based packet filtering.
TCP connections and UDP pseudo connections will be tracked separately even if
theaddresses and ports are identical. Including the protocol in the hash key
will ensure this.
The Input FIFO contains all the incoming packets for vFW filtering. The vFW
Filter has no dependency on which component has written to the Input FIFO.
Packets will be dequeued from the FIFO in bulk for processing by the vFW.
Packets will be enqueued to the output FIFO.
The software or hardware loadbalancing can be used for traffic distribution
across multiple worker threads. The hardware loadbalancing require ethernet
flow director support from hardware (eg. Fortville x710 NIC card).
The Input and Output FIFOs will be implemented using DPDK Ring Buffers.
Components of vFW
=================
In vFW, each component is constructed using packet framework pipelines.
It includes Rx and Tx Driver, Master pipeline, load balancer pipeline and
vfw worker pipeline components. A Pipeline framework is a collection of input
ports, table(s),output ports and actions (functions).
---------------------------
Receive and Transmit Driver
---------------------------
Packets will be received in bulk and provided to LoadBalancer(LB) thread.
Transimit takes packets from worker threads in a dedicated ring and sent to
hardware queue.
---------------
Master Pipeline
---------------
The Master component is part of all the IP Pipeline applications. This component
does not process any packets and should configure with Core 0, to allow
other cores for processing of the traffic. This component is responsible for
1. Initializing each component of the Pipeline application in different threads
2. Providing CLI shell for the user control/debug
3. Propagating the commands from user to the corresponding components
----------------
ARPICMP Pipeline
----------------
This pipeline processes the APRICMP packets.
--------------
TXRX Pipelines
--------------
The TXTX and RXRX pipelines are pass through pipelines to forward both ingress
and egress traffic to Loadbalancer. This is required when the Software
Loadbalancer is used.
----------------------
Load Balancer Pipeline
----------------------
The vFW support both hardware and software balancing for load balancing of
traffic across multiple VNF threads. The Hardware load balancing require support
from hardware like Flow Director for steering of packets to application through
hardware queues.
The Software Load balancer is also supported if hardware load balancing can't be
used for any reason. The TXRX along with LOADB pipeline provides support for
software load balancing by distributing the flows to Multiple vFW worker
threads.
Loadbalancer (HW or SW) distributes traffic based on the 5 tuple (src addr, src
port, dest addr, dest port and protocol) applying an XOR logic distributing to
active worker threads, thereby maintaining an affinity of flows to worker
threads.
------------
vFW Pipeline
------------
The vFW performs the basic packet filtering and will drop the invalid and
malformed packets.The Dynamic packet filtering done using the connection tracker
library. The packets are processed in bulk and Hash table is used to maintain
the connection details.
Every TCP/UDP packets are passed through connection tracker library for valid
connection. The ACL library integrated to firewall provide rule based filtering.
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