ARP PACKET PROCESSING METHOD, COMMUNICATION SYSTEM AND DEVICE

• US 20100054253A1
• Filed: 11/06/2009
• Published: 03/04/2010
• Est. Priority Date: 07/20/2007
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Li, Zhenhai
• Granted Patent: US 8,542,684 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/745 Address table lookup; Address filtering
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002

Abstract

An Address Resolution Protocol (ARP) packet processing method, a communication system and a device are disclosed. The method includes: receiving an ARP packet, and judging the type of the ARP packet; when the ARP packet is an ARP request, responding to the ARP request if an entry corresponding to the ARP request is found in a local ARP table; and when the ARP packet is an ARP response, reporting the ARP response if an entry corresponding to the ARP response is found in the local ARP table and a reporting parameter in the entry indicates permission of reporting; or discarding the ARP response if no entry corresponding to the ARP response is found in the ARP table.

Claims

1. An Address Resolution Protocol (ARP) packet processing method, comprising:

receiving an ARP packet, and judging the type of the ARP packet;

when the ARP packet is an ARP request, responding to the ARP request if an entry corresponding to the ARP request is found in a local ARP table; and

when the ARP packet is an ARP response, reporting the ARP response if an entry corresponding to the ARP response is found in the local ARP table and a reporting parameter in the entry corresponding to the ARP response indicates permission of reporting;

or discarding the ARP response if no entry corresponding to the ARP response is found in the ARP table.

2. The ARP packet processing method of claim 1, further comprising:

when the ARP packet is the ARP request, judging whether a proxy ARP function is enabled on an interface that receives the ARP request if no entry corresponding to the ARP request is found in the ARP table;

if the proxy ARP function is enabled, limiting the speed of the ARP request, and then reporting the ARP request to a control plane processor; and

if the proxy ARP function is not enabled, discarding the ARP request.

3. The ARP packet processing method of claim 1, further comprising:

when the ARP packet is the ARP response, if the entry corresponding to the ARP response is found in the ARP table, and the reporting parameter in the entry indicates no permission of reporting,

limiting the speed of the ARP response and then reporting the ARP response to a control plane processor, or discarding the ARP response.

4. The ARP packet processing method of claim 1, further comprising:

if the ARP packet is the ARP request,

searching the ARP table according to a port number of the ARP request, a Virtual Local Area Network (VLAN) ID, and a destination Internet Protocol (IP) address.

5. The ARP packet processing method of claim 1, wherein before responding to the ARP request, the method further comprises:

if the entry corresponding to the ARP request is not a gateway ARP entry or a proxy ARP entry, discarding the ARP request.

6. The ARP packet processing method of claim 1, further comprising:

if the ARP packet is an ARP response, searching the ARP table according to a source Internet Protocol (IP) address of the ARP response.

7. The ARP packet processing method of claim 1, wherein after reporting the ARP response, the method further comprises:

modifying the reporting parameter in the entry corresponding to the ARP response in the ARP table to no permission of reporting.

8. A communication system, comprising:

a forwarding plane processor, adapted to receive an Address Resolution Protocol (ARP) packet, and judge the type of the ARP packet;

when the ARP packet is an ARP request, respond to the ARP request if an entry corresponding to the ARP request is found in a local ARP table;

when the ARP packet is an ARP response, report the ARP response if an entry corresponding to the ARP response is found in the local ARP table and a reporting parameter in the entry corresponding to the ARP response indicates permission of reporting;

or discard the ARP response if no entry corresponding to the ARP response is found in the ARP table; and

a control plane processor, adapted to receive the ARP request or ARP response reported by the forwarding plane processor.

9. A forwarding plane processor, comprising:

a judging unit, adapted to judge the type of a received Address Resolution Protocol (ARP) packet;

a first searching unit, adapted to search a local ARP table when the judging unit determines that the ARP packet is an ARP request;

a responding unit, adapted to respond to the ARP request if the first searching unit finds an entry corresponding to the ARP request;

a second searching unit, adapted to search the local ARP table when the judging unit determines that the ARP packet is an ARP response; and

a discarding unit, adapted to discard the ARP response if the second searching unit finds no entry corresponding to the ARP response.

10. The forwarding plane processor of claim 9, further comprising:

a speed limiting unit, adapted to limit the speed of the ARP packet and report the ARP packet to a control plane processor;

an interface judging unit, adapted to judge whether a proxy ARP function is enabled on an interface that receives the ARP request when the first searching unit finds no entry corresponding to the received ARP request in the ARP table;

if the proxy ARP function is enabled, instruct the speed limiting unit to limit the speed of the ARP request and report the ARP request;

if the proxy ARP function is not enabled, instruct the discarding unit to discard the ARP request.

11. The forwarding plane processor of claim 9, further comprising:

a checking unit, adapted to judge whether a reporting parameter in the entry corresponding to the ARP response indicates permission of reporting when the entry corresponding to the ARP response is found in the ARP table; and

a reporting unit, adapted to report the ARP response when the reporting parameter in the entry indicates permission of reporting.