System, method and apparatus for use in monitoring or controlling internet access

• US 20060075072A1
• Filed: 09/28/2004
• Published: 04/06/2006
• Est. Priority Date: 09/09/2004
• Status: Active Grant

• Current Assignee: Forcepoint LLC
• Original Assignee: Websense UK Ltd. (Forcepoint LLC)
• Inventors: Sinclair, John W., Nash, Alistair H., Pettener, Ian James
• Granted Patent: US 7,590,716 B2
• Time in Patent Office: Days
• US Class Current: 709/219
• CPC Class Codes: G11B 20/00847 wherein the usage restriction is defined by a licence file
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/30 Managing network names, e.g. use of aliases or nicknames name-to-address mapping H04L61/45
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/102 Entity profiles
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation

Abstract

An apparatus method and system are described for categorising Uniform Resource Locators (URLs) when accessing the Internet 20 from a client 12. A request message 500 is generated to request categorisation of a specified URL, and a category is provided in a reply message 600. The specified URL and the category are added to a category cache. In a second or subsequent instance of a URL request referring to the specified URL, the category is determined from the category cache. This reduces communication traffic in a network such as the Internet 20.

Claims

1. A method of categorising Uniform Resource Locators (URLs) during Internet access, comprising the steps of:

receiving a URL request denoting a specified URL;

generating a request message to request categorisation of the specified URL;

receiving a reply message denoting a category for the specified URL amongst a predetermined set of categories;

adding the specified URL and the category to a category cache; and

in a second or subsequent instance of a URL request with respect to the specified URL, determining the category of the specified URL from the category cache.

2. The method of claim 1, wherein the category cache comprises:

a hash array wherein the host portion of the specified URL is hashed to produce an index element in the hash array; and

a combined host tree and age list wherein each tree node of the host tree comprises URL data representing a specified URL and a corresponding category, and each tree node further comprises a next pointer and a previous pointer which refer to a next older tree node and a previous newer tree node, respectively, to form an age list.

3. The method of claim 2, comprising adding new tree nodes to a head of the age list.

4. The method of claim 2, comprising removing an oldest tree node from a tail of the age list when the category cache has reached a predetermined maximum size.

5. The method of claim 2, comprising moving any host that is re-visited to a head of the age list.

6. The method of claim 2, wherein the hash array has a predetermined length.

7. The method of claim 6, wherein the predetermined length of the hash array is set by a variable which is input from a control panel during use.

8. The method of claim 2, comprising:

searching the category cache for the specified URL; and

returning a category code for the specified URL from the category cache, or else generating the request message to request categorisation of the specified URL.

9. The method of claim 2, wherein each specified URL comprises a host portion and a path portion, and each tree node comprises a host string holding the host portion, and an array of one or more page strings each representing a path portion depending from the host portion.

10. The method of claim 9, comprising:

extracting a URL host portion and a URL path portion from the specified URL, hashing the host portion to determine an index element in the hash array, searching the host tree identified by the index element to locate a tree node matching the host portion, matching a URL path portion with a page string in the array, and returning a stored category associated with the specified URL.

11. The method of claim 9, wherein the category cache comprises, within each tree node, a children flag which identifies whether category codes are available for children of a specified URL host or URL path.

12. The method of claim 1, comprising providing a custom cache alongside the category cache, wherein the custom cache records a customised list of stored URLs and associated category codes.

13. The method of claim 12, wherein the custom cache comprises:

a hash array wherein the host portion of a specified URL is hashed to produce an index element in the hash array; and

a host tree wherein each tree node of the host tree comprises URL data representing a specified URL and a corresponding category code.

14. The method of claim 12, comprising, in order, the steps of searching a specified URL in the custom cache and returning a category code, or else searching the specified URL in the category cache and returning a category code, or else generating a request message to request categorisation of the specified URL and receiving a reply message returning a category code.

39. A program storage medium having computer executable instructions stored thereon for performing the method of claim 1.

15. A method for use in controlling or monitoring Internet access at a client device by categorising Uniform Resource Locators (URLs), comprising the steps of:

receiving a specified URL;

searching a category cache held at the client device using the specified URL as a search key, and returning a category code associated with the specified URL when a match is found for the specified URL; and

generating a request message to request a category code for the specified URL, when a match is not found for the specified URL.

16. The method of claim 15, comprising the steps of:

receiving a specified URL from a client software function within the client device; and

passing the category code to the client software function in return.

17. The method of claim 15, comprising:

sending the request message to a remote categorisation service;

receiving a reply message from the remote categorisation service denoting a category code for the specified URL amongst a predetermined set of categories.

18. The method of claim 17, further comprising:

adding the specified URL and the category code to the category cache.

19. The method of claim 15, wherein the method comprises:

hashing at least part of the specified URL to reference an index element for a hash array within the category cache; and

using the index element as a pointer to a combined host tree and age list comprising one or more tree nodes, wherein each tree node comprises URL data representing a URL and one or more corresponding category codes, and each tree node further comprises an age list next pointer referring to an adjacent older tree node and an age list previous pointer referring to an adjacent newer tree node; and

searching the combined host tree and age list for a tree node containing URL data which matches the specified URL.

20. The method of claim 19, wherein each tree node comprises a host string holding a host portion of a URL and an associated category code, and a page array of zero or more page strings each page string holding a page portion and an associated category code, and the method comprises selecting a tree node by a host portion of a specified URL, and selecting a page string in the page array matching all or part of a page portion of a specified URL, to thereby retrieve a category code for the specified URL.

21. The method of claim 20, wherein each page string further comprises a children flag indicating whether category codes are available for children of a stored path portion.

22. The method of claim 19, comprising the steps of determining an oldest tree node at a tail of the age list and removing the oldest tree node when the category cache has reached a predetermined maximum size.

23. The method of claim 22, comprising the steps of adding a new tree node and updating the age list to place the new tree node at a head of the age list.

24. The method of claim 19, comprising, when the searching step determines a tree node matching the specified URL, updating to place the matched tree node at the head of the age list.

40. A program storage medium having computer executable instructions stored thereon for performing the method of claim 15.

25. A system for use in controlling or monitoring of Internet access by categorising Uniform Resource Locators (URLs), comprising:

a client device arranged to monitor or control Internet access according to a category code of a specified URL, and including a categorisation module to provide the category code for the specified URL from a category cache stored at the client device or else generate a request message to request categorisation of the specified URL; and

a categorisation server coupled to communicate with the client device and arranged to receive the request message and to send a reply message identifying a category code for the specified URL.

26. The system of claim 25, wherein the client device and the categorisation server communicate over the Internet.

27. The system of claim 25, wherein the client device comprises a user machine to provide a human-oriented user interface, and a client internet gateway appliance to couple the user machine to the Internet through an Internet Service Provider (ISP).

28. The system of claim 27, wherein the user machine and the client internet gateway appliance are formed within a single integrated device.

29. The system of claim 27, wherein the user machine and the client internet gateway appliance are separate devices arranged to communicate over a local network.

30. The system of claim 25, wherein the client device and the categorisation sever are arranged to communicate over a local area network.

31. A client device, comprising:

an interface module arranged to present a URL categorisation function, wherein the interface module is arranged to receive a specified URL from a client software and to return a category code;

a category cache holding a plurality of stored URLs and associated category codes, such that matching the specified URL against one of the stored URLs provides the category code; and

a communication module arranged to send an outgoing request message to a categorisation server when there is no match in the category cache and to receive and buffer incoming data including a corresponding reply message, wherein the request message comprises the specified URL and the reply message comprises the category code.

32. The client device of claim 31, wherein the client device is arranged to add the specified URL and the category code to the stored URLs and associated category codes in the category cache.

33. The client device of claim 31, further comprising:

a custom cache which holds a customised list of stored URLs and associated category codes, such that the custom cache is searchable instead of or as well as the category cache.

34. A cache structure, comprising:

a hash array comprising one or more index elements, each index element comprising a host tree pointer and a hash key derived from a stored URL; and

one or more host trees depending from the index elements of the hash array, each host tree comprising one or more tree nodes each holding URL data representing stored URLs and associated category codes; and

an age list to list each of the tree nodes by age, wherein the age list comprises, within each tree node, a next pointer and a previous pointer which refer to a next older tree node and a previous newer tree node, respectively.

35. The cache structure of claim 34, wherein each tree node comprises a host string holding a host portion of a stored URL and an associated category code, and a page array of zero or more page strings each page string holding a page portion and an associated category code.

36. The cache structure of claim 35, wherein each page string comprises a children flag denoting whether category codes are available for children of a stored URL path portion.

37. The cache structure of claim 34, wherein each tree node further comprises a parent node pointer, a left node pointer, and a right node pointer.

38. The cache structure of claim 36, wherein the tree list is a balanced red-black tree and each tree node further comprises a red-black flag.