US 6,609,159 B1 · Methods, systems, and machine readable programming for interposing front end servers between servers and clients

Abstract

A client-server system includes a new front end server which interposes itself between a prior (back end) server and its clients using an interposed dynamically-loaded library linked to the back end. The interposed library and front end can provide enhanced services without requiring reconfiguration of either the back end server or its clients. The front end can accept network connections on the same port as the back end server is programmed to. The interposed library intercepts standard network system calls by the back end and emulates their behavior by communicating with the front end. The front end can send file descriptors of either direct connections with clients, or of pipes for relaying requests and response from and to clients through the front end, to the interposed library for return to calls by the back end to accept connections. The capabilities which the front end can provide include caching, protocol conversion, session affinity, filtering, traffic conversion, and spreading load between multiple back end processes.

Claims28

Dependent claims

Computer programming recorded in computer readable memory designed to be used on a host computer system having an operating system including calls for communicating with remote client programs running on other computer systems connected to the host over a computer network, said programming comprising a dynamically-loaded library which includes:

programming which enables the library to intercept certain standard operating system calls made by a back end server program running in the same operating system space as the library, including programming which causes the library to intercept a standard accept call from the back end server which instructs the operating system to accept a connection from a remote client over the computer network;
programming which responds to the intercept of such an accept call by communicating, through a pipe, a representation of the accept call and its parameters to a front end server program running as a separate process in the same operating system space as the library;
programming which receives from the front end server, over a pipe, a socket associated with a connection with a remote client established by the front end server;
and
programming which returns program flow from the library's execution of the accept call back to the back end server with information specifying the socket received from the front end server in the same format in which the operating system returns socket information in response to an accept call.

2 more elements

A computerized method for interposing a front end server between a back end server program running in a given operating system space on a given computer and one or more client programs running on remote computers connected to the given computer via a computer network, comprising:

running an interposed dynamically-loaded library which is linked to the back end server in the given operating system space;
running a front end server program which is loaded in the given operating system space;
using the library to respond to standard operating system calls by the back end server, including using the library to respond to an operating system call by the back end server to accept a connection from a remote client by communicating the call and its parameters to the font end server over a first pipe;
using the font end server to accept a connection from a remote client;
using the font end server to communicate a socket associated with the client connection to the library;
and
using the library to return program flow from the library's execution of the accept call back to the back end server with information specifying the socket received from the front end server in the same format in which the operating system returns socket information in response to an accept call.

4 more elements

A computer system for serving requests from remote clients connected to the system over a computer network, the system comprising:

operating system programming loaded in memory and providing a given operating system space within that memory;
a back end server program loaded in the given operating system space;
an interposed dynamically-loaded library loaded in the given operating system space and linked to the back end server;
and
a front end server program loaded in the given operating system space;
wherein:
the library includes programming which responds to standard operating system calls by the back end server, including programming which responds to a call by the back end server to accept a connection from a remote client by communicating the call and its parameters to the font end server through a pipe between the library and the front end server;
the front end server includes:
programming which accepts a connection from a remote client;
and
programming which communicates a socket associated with the client connection to the library through a pipe between the front end server and the library;
and
the library further includes programming which returns program flow from the library's execution of the accept call back to the back end server with information specifying the socket received from the front end server in the same format in which the operating system returns socket information in response to an accept call.

10 more elements

Dependencies are inferred from the claim text.

Methods, systems, and machine readable programming for interposing front end servers between servers and clients

Life of this patent

Methods, systems, and machine readable programming for interposing front end servers between servers and clients

Life of this patent

Abstract

Claims28