RU2541118C2 - Connection processing system and method using temporary port - Google Patents

Abstract

FIELD: physics, computer engineering.

SUBSTANCE: invention relates to connection processing systems and methods using a temporary port. The technical result is achieved using a proxy server which imitates a status from the server through changes in the states of the temporary port. The connection processing system using a temporary port comprises an application, an interception means, a connection establishing means and a remote server. The application initiates connection establishment with the remote server by sending network requests. The interception means intercepts network requests from the application to the remote server and initiates creation of a temporary port. The connection establishing means establishes a connection with the remote server after interception, creates a temporary port and imitates the status from the server by changing the state of the created temporary port. The remote server establishes a connection in response to the network requests.

EFFECT: enabling establishment or termination of a connection between an application and a remote server.

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Description

Technical field

The invention relates to systems and methods for processing a connection using a temporary port.

State of the art

Currently, personal computer users are often faced with the need to have a connection to the global Internet. The list of programs for which Internet connection is a prerequisite for work is also steadily growing, while the volume of data transmitted through the network is growing. At the same time, the organization of a network connection becomes more complex and larger, which, in turn, affects the quality and speed of data transfer.

To ensure access of computers on the local network to the Internet, a proxy server is often used. In its simplest implementation, a proxy server is a network service that is necessary to establish a connection between an application and a remote server on the Internet. The basis of the proxy server is a mechanism for intercepting and redirecting connections. The development of the aforementioned mechanism is carried out using various Application Programming Interface (API), which have functions for working with network ports and connections.

The main problem when using proxies for TCP connections is the imitation of the connection status transmitted from the server. It is important that the proxy server does not allow the connection to the port that it provided to the application until it checks the status of the connection sent from the remote server and establishes a connection with it. Proxy servers that incorrectly implement the mechanism for intercepting and redirecting connections are often a slowing factor in data transfer, and in some cases can cause loss of connection between nodes.

Figure 1 shows the connection setup of an application 110 with a remote server 130 using a proxy server 120, which has the problem of simulating the connection status from the server. The connection is established within the TCP / IP protocol stack. All connection and port states via TCP are described in RFC 793. Application 110, such as a browser, initiates a call to the remote server 130. In response, the DNS server provides a list of addresses that correspond to the remote server 130. Application 110 initiates a connection and sends a TCP request SYN at the address from the list from the DNS server. The proxy server 120 intercepts the request, creates the port and opens it by calling the passive OPEN command, simultaneously sends the request to the address received from application 110 to establish a connection with the remote server 130 and informs application 110 that the request to the current address will be redirected. To start establishing a TCP connection according to RFC 793, you must run the OPEN command. On the proxy server, the OPEN command is called in passive mode. The result of making a passive OPEN call is to open the port and put the connection into LISTEN state. In this state, the port is open, but does not take any action to establish a connection, but expects an incoming connection. Application 110, when re-accessing the address from the list from the DNS server, is redirected by the proxy server to the open port. The proxy port 120 accepts the expected incoming connection. Between the application 110 and the proxy server 120, the exchange of requests begins, the connection is established. Since the connection was successful, the application 110 completes the polling of addresses from the list from the DNS server and starts polling the remote server 130 for data transfer. If the proxy server 120 is unable to establish a connection with the remote server 130, the port through which the application 110 has established a connection with the proxy server 120 is closed. Application 110 receives a message stating that the server unexpectedly disconnected.

Thus, the application 110 does not resume polling addresses from the list from the DNS server, but also does not have an established connection with the remote server 130.

In one embodiment, when programming a proxy server, the Posix standard Berkeley sockets library is used, which contains connection management APIs. For most operating systems, this method of implementing proxy servers is preferred. In implementations using the API, the bind () and listen () functions are used to perform the above actions. The bind () function is used to bind the port and the process, and the listen () function is used to call the passive OPEN command and put the connection into the LISTEN state. The listen () function should not be confused with the state of the LISTEN connection.

To date, systems and methods for organizing a connection using a proxy server are known. Most of these systems are based on the use of the bind () and listen () API functions.

Publication US7161947 B1 describes an interception algorithm without loss of connection with the creation of a dynamic (intermediate) port. In particular, a passive connection method is described when a user, an interceptor, a proxy server, and a remote server participate in the operation of the algorithm. It should be noted that the problem of simulating the status from the server when establishing a connection through a proxy server is not covered in this publication.

The publication “The Remote Socket Architecture))) (http: //vv4vw.tkn.tu- 12 / TKN-dissertations / schlaeger_morten.pdf) describes an example connection organization scenario. Sockets are created on both sides, they are associated with the final address and the server socket is put into listening mode using the bind () and listen () functions. But in this publication, there is no information on solving the problem of simulating the status from a remote server when establishing a connection through a proxy server.

The proposed and described further system and method for processing a connection using a temporary port circumvents the problem described above.

An analysis of the prior art and the possibilities that arise when combining existing solutions in one system allows you to get a new result, namely the system and method of processing the connection using a temporary port.

Disclosure of invention

The present invention is intended to process a connection using a temporary port.

The technical result of the present invention is to establish or close the connection between the application and the remote server. The specified technical result is achieved through the use of a proxy server that simulates the status from the server.

The connection processing system using a temporary port contains an application that initiates the establishment of a connection to a remote server by sending network requests; interception tool designed to intercept network requests from an application to a remote server, initiate the creation of a temporary port; connection setup tool designed to establish a connection with a remote server after being intercepted by an interception tool, creating a temporary port, simulating the status from the server by changing the state of the created temporary port; A remote server that establishes a connection in response to network requests.

In the particular case of system implementation, before starting sending network requests to establish a connection, the application receives a list of addresses from the DNS server.

In another particular case of the system implementation, the interception tool transfers the address of the remote server received from the application to the connection setup tool.

In another particular case of the system implementation, the connection setup tool changes the state of the created temporary port, namely, it opens the port when the connection with the remote server is established; closes ports when a connection to a remote server is not established; when the remote server does not respond, it waits for a response from the remote server and closes the port after a period of time to establish a connection.

A method for processing a connection using a temporary port in which a connection to a remote server is initiated by sending network requests; intercept network requests; establish a connection with a remote server after interception; create a temporary port; simulate the status from the server by changing the status of the temporary port.

In the particular case of the implementation of the method for connecting to a remote server, its addresses are obtained from the DNS server using the application.

In another particular case of implementing the method, the remote server address received from the application is transmitted to the connection setup tool using the interception tool.

In another particular case of the implementation of the method, the state of the temporary port is changed: when the connection with the remote server is established, open the port; when the connection to the remote server is not established, close the port; when the remote server does not respond, wait for the connection to be established and close the port after a period of time to establish the connection.

Brief Description of the Drawings

Additional objectives, features and advantages of the present invention will be apparent from reading the following description of an embodiment of the invention with reference to the accompanying drawings, in which:

Figure 1 shows a diagram of the connection between the application and the remote server using a proxy server, which has the problem of simulating status from the server in the case when the server is unavailable;

Figure 2 illustrates the operation of the connection processing system using the temporary port in the case when the server is unavailable;

Figure 3 shows the operation of the connection processing system using the temporary port in the case when the server is available;

Figure 4 shows a diagram of a connection processing algorithm using a temporary port;

5 is an example of a general purpose computer system, personal computer, or server.

Although the invention may have various modifications and alternative forms, the characteristic features shown by way of example in the drawings will be described in detail. It should be understood, however, that the purpose of the description is not to limit the invention to its specific embodiment. On the contrary, the purpose of the description is to cover all changes, modifications that are within the scope of this invention, as defined in the attached formula.

Description of Embodiments

The objects and features of the present invention, methods for achieving these objects and features will become apparent by reference to exemplary embodiments. However, the present invention is not limited to the exemplary embodiments disclosed below, it can be embodied in various forms. The essence described in the description is nothing more than the specific details necessary to assist the specialist in the field of technology in a comprehensive understanding of the invention, and the present invention is defined in the scope of the attached claims.

To start establishing a TCP connection according to RFC 793, you must run the OPEN command. On the proxy server, the OPEN command is called in passive mode. The result of making a passive OPEN call is to open the port and put the connection into LISTEN state. In this state, the port does not take any action to establish a connection, but expects an incoming connection.

In one embodiment, when programming a proxy server, the Posix standard Berkeley sockets library is used, which contains connection management APIs. In implementations using the API, the bind () and listen () functions are used to perform the above actions. The bind () function is used to bind the port and the process, and the listen () function is used to call the passive OPEN command and put the connection into the LISTEN state. The listen () function should not be confused with the state of the LISTEN connection.

The connection status transmitted from the server is information about the status of the network connection after sending network requests. In general, for the proxy server to work correctly, it is necessary to simulate three connection statuses transmitted from the server, although the total number of connection statuses may be greater. The server may be available, not responding, and unavailable. When the server is available, upon receipt of network connection requests, a connection is established. If the server does not respond, all network connection requests do not reach the server. Requests are repeated for a limited period of time. When the server is not available, in response to network connection requests, a connection setup error message is received.

In general, the block diagram of the operation of the connection processing system using the temporary port 205 between the application 210 and the remote server 240 in the case where the remote server 240 is unavailable has the form shown in FIG. 2. The connection processing system using temporary port 205 consists of interception means 220 and connection establishment means 230. Interception means 220 is designed to intercept and redirect network requests from application 210, transmit the address of remote server 240, and execute a request to create a temporary port to connection establishment 230. Connection setup tool 230 is designed to create a temporary port and transmit port information to interception tool 220, establish a connection to remote server 240, and After a successful connection is redirected between the application 210 and the remote server 240. The application 210, for example, a browser, initiates a call to the remote server 240. In response, the DNS server provides a list of addresses that correspond to the remote server 240. The application 210 initiates a connection to the address from the list from DNS server and sends a TCP SYN request. The interception tool 220 intercepts the connection, sends a request to the connection setup tool 230 to create a temporary port and reports the address of the remote server with which it needs to establish a connection, then after creating the temporary port, it starts redirecting connection requests from application 210 to the temporary port. Connection setup tool 230 starts establishing a connection at the address received from the request, creates a temporary port by calling the bind () API function and reports port information to interception tool 220. The result of the above function is to reserve a temporary port in the TCP protocol stack. The connection through the port is not established because it is not open, but no ICMP messages are returned in response to the port being created. ICMP (Internet Control Message Protocol) is used to send error messages and other exceptional situations that occur during data transfer, for example, the requested service is unavailable, the server or router is not responding. Thus, the status from the server to which the connection establishment procedure is started but not completed is simulated. Attempts by application 210 to establish a connection with the port being redirected will be unsuccessful, but will not lead to the completion of the connection, application 210 will continue to send TCP SYN requests. If the connection setup tool 230 fails to establish a connection with the remote server, the temporary port will be closed. At the next TCP SYN request of application 210, an ICMP port unavailability message will be returned, which is a simulation of the status from the server when it is unavailable. If the connection setup tool 230 does not establish a connection with the remote server 240 after a time period for establishing a connection (time out) has elapsed, the port will exist until the time period for establishing the connection has expired on the application 210 side. Thus, the status from the server is simulated, the connection to which could not be established due to the expiration of the time period for establishing the connection (time out). Since the connection to the remote server 240 was never established, application 210 will continue to poll addresses from the list from the DNS server.

In the General case, the block diagram of the operation of the connection processing system using the temporary port 205 between the application 210 and the remote server 240 in the case when the remote server 240 is unavailable, has the form shown in Fig.3. Application 210, such as a browser, initiates a call to the remote server 240. In response, the DNS server provides a list of addresses that correspond to the remote server 240. Application 210 initiates a connection to the address from the list from the DNS server and sends a TCP SYN request. The interception tool 220 intercepts the connection, sends a request to the connection setup tool 230 to create a temporary port and reports the address of the remote server 240 with which it is necessary to establish a connection, then starts redirecting connection requests from the application 210 to the temporary port. The connection setup tool 230 starts the connection at the address received from the request, creates a temporary port by calling the bind () API function, and reports the port information to the interception tool 220. In case the remote server 240 is available and the connection setup tool 230 establishes a connection , the port will be opened by calling the HstenQ function. Subsequently, after successfully connecting the application 210 to the remote server 240, the temporary port will be closed. Thus, the status of the server that is available is simulated.

Figure 4 shows a diagram of the algorithm for establishing a connection using a proxy server. At step 410, the application 210, such as a browser, initiates a call to the remote server 240. In response, the DNS server provides a list of addresses that correspond to the remote server 240. At step 420, the application 210 initiates a connection to the address from the list from the DNS server and sends a request TCP SYN. In the event of an unsuccessful attempt to establish a connection with the remote server 240, application 210 will proceed to establish a connection with a different address from the list from the DNS server until the list ends. At step 430, the connection processing system using the temporary port 205, using interception tool 220, intercepts the connection request to the remote server 240 and forwards the address to which the connection is to be established, and the port creation request to the connection setup tool 230. At step 440, the installation tool connection 230 initiates a connection with the remote server 240 at the address received from the interception tool 220. At step 450, the connection setup tool 230 creates a temporary port using the bind () function, informs inf rmatsiyu the port interception means 220 simulates the status of the server that is started, but not finished, a connection procedure. At 460, all requests from application 210 are redirected to the created port. At step 470, the connection setup tool 230, if the connection to the remote server 240 failed, closes the port. Thus, the status from the server with which it was not possible to establish a connection is simulated. If a connection to the remote server 140 is established, then the connection setup tool 230, by calling the listen () function, opens the port and starts responding to the application 210. The status from the server with which it was able to establish a connection is simulated. At step 480, application 210 sends another request to establish a connection to the current address from the list from the DNS server. In the case when the port is open, step 490, the application starts exchanging data with the remote server 240. Otherwise, the application 210 proceeds to step 420 and initiates a connection with the next address from the list from the DNS server.

5 is an example of a general purpose computer system, a personal computer or server 20 comprising a central processor 21, a system memory 22, and a system bus 23 that contains various system components, including memory associated with the central processor 21. The system bus 23 is implemented like any bus structure known in the art, which in turn contains a bus memory or a bus memory controller, a peripheral bus and a local bus that is capable of interacting with any other bus architecture. The system memory contains read-only memory (ROM) 24, random access memory (RAM) 25. The main input / output system (BIOS) 26 contains the basic procedures that ensure the transfer of information between the elements of the personal computer 20, for example, at the time of loading the operating system using ROM 24.

The personal computer 20 in turn contains a hard disk 27 for reading and writing data, a magnetic disk drive 28 for reading and writing to removable magnetic disks 29, and an optical drive 30 for reading and writing to removable optical disks 31, such as a CD-ROM, DVD -ROM and other optical information carriers. The hard disk 27, the magnetic disk drive 28, the optical drive 30 are connected to the system bus 23 through the interface of the hard disk 32, the interface of the magnetic disks 33 and the interface of the optical drive 34, respectively. Drives and associated computer storage media are non-volatile means of storing computer instructions, data structures, software modules and other data of a personal computer 20.

The present description discloses an implementation of a system that uses a hard disk 27, a removable magnetic disk 29, and a removable optical disk 31, but it should be understood that other types of computer storage media 56 that can store data in a form readable by a computer (solid state drives, flash memory cards, digital disks, random access memory (RAM), etc.) that are connected to the system bus 23 through the controller 55.

Computer 20 has a file system 36 where the recorded operating system 35 is stored, as well as additional software applications 37, other program modules 38, and program data 39. The user is able to enter commands and information into personal computer 20 via input devices (keyboard 40, keypad “ the mouse "42). Other input devices (not displayed) can be used: microphone, joystick, game console, scanner, etc. Such input devices are, as usual, connected to the computer system 20 via a serial port 46, which in turn is connected to the system bus, but can be connected in another way, for example, using a parallel port, a game port, or a universal serial bus (USB). A monitor 47 or other type of display device is also connected to the system bus 23 via an interface such as a video adapter 48. In addition to the monitor 47, the personal computer may be equipped with other peripheral output devices (not displayed), such as speakers, a printer, and the like.

The personal computer 20 is capable of operating in a networked environment, using a network connection with another or more remote computers 49. The remote computer (or computers) 49 are the same personal computers or servers that have most or all of the elements mentioned earlier in the description of the creature the personal computer 20 of FIG. 5. Other devices, such as routers, network stations, peer-to-peer devices, or other network nodes may also be present on the computer network.

Network connections can form a local area network (LAN) 50 and a wide area network (WAN). Such networks are used in corporate computer networks, internal networks of companies and, as a rule, have access to the Internet. In LAN or WAN networks, the personal computer 20 is connected to the local area network 50 via a network adapter or network interface 51. When using the networks, the personal computer 20 may use a modem 54 or other means of providing communication with a global computer network such as the Internet. The modem 54, which is an internal or external device, is connected to the system bus 23 via the serial port 46. It should be clarified that the network connections are only exemplary and are not required to display the exact network configuration, i.e. in reality, there are other ways to establish a technical connection between one computer and another.

In conclusion, it should be noted that the information provided in the description are only examples that do not limit the scope of the present invention defined by the claims.

Claims (8)

1. A connection processing system using a temporary port, which contains:
a) an application that initiates a connection to a remote server by sending network requests;
b) an interception tool designed to intercept network requests from an application to a remote server and initiate the creation of a temporary port;
c) a connection setup tool designed to establish a connection with a remote server after being intercepted by a capture tool, creating a temporary port and simulating the status from the server by changing the state of the created temporary port;
d) a remote server that establishes a connection in response to network requests. 2. The system according to claim 1, in which before sending network requests to establish a connection, the application receives a list of addresses from the DNS server. 3. The system according to claim 1, in which the means of interception transmits the address of the remote server received from the application to the connection setup tool. 4. The system according to claim 1, in which the connection setup tool changes the state of the created temporary port:
A) opens the port when a connection to the remote server is established;
B) closes the port when the connection to the remote server is not established;
B) when the remote server does not respond, it waits for a response from the remote server and closes the port after a period of time to establish a connection. 5. A method for processing a connection using a temporary port in which:
a) initiate a connection with a remote server by sending network requests;
b) intercept network requests;
c) establish a connection with a remote server after interception;
d) create a temporary port;
d) simulate the status from the server by changing the status of the temporary port. 6. The method according to claim 5, in which to connect to a remote server receive its address from the DNS server using the application. 7. The method according to claim 5, in which the address of the remote server received from the application is transmitted to the connection setup tool using the interception tool. 8. The method according to claim 5, in which the state of the temporary port is changed:
A) when the connection with the remote server is established, open the port;
B) when the connection to the remote server is not established, close the port;
B) when the remote server does not respond, wait for the connection to be established and close the port after a period of time to establish the connection.

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