CN1299485C - Method for setting waiting time for completely closing transmission control procotol connection - Google Patents

Abstract

The invention provides a method for setting the waiting time for full closing of transmission control protocol connections. The method is as follows: firstly, the client sends a request to close the connection for active closing; after receiving the confirmation from the server, the client enters the full closing waiting state ; The client starts the timer and provides a configuration management interface for the variable of the waiting time for the transmission control protocol connection to be completely closed; then, the client determines the setting of the waiting time for the transmission control protocol connection to be completely closed through the configuration management interface, and determines the corresponding Full close waiting time value; finally, the client finishes closing the connection and releases the corresponding resources. The present invention changes the existing shortcoming that the value of the existing timer is controlled by a macro and cannot be changed conveniently, thereby effectively preventing an attacker from establishing a large number of semi-connections in a short time to consume system connection resources.

Description

How to set the waiting time for transmission control protocol connection full close

technical field

The invention relates to the technical field of network communication, in particular to a method for setting a transmission control protocol connection full-close waiting time.

Background technique

During the network communication process, the client usually transmits data by establishing a TCP (Transmission Control Protocol) connection with the server; after the data transmission process is completed, the established connection needs to be closed to release connection resources for other connections. As shown in Figure 1, when the client closes the connection, it first sends a FIN (connection close request) to actively close it. After receiving the confirmation from the server, the local end enters the FIN_WAIT_2 (full close wait) state, waiting for the server-side application to realize it. An end-of-file description has been received, and a FIN is sent to the local end to close the connection in the other direction, and the TCP connection of the local end will migrate from the FIN_WAIT_2 state to the TIME_WAIT (time waiting) state until the TCP connection is completely closed.

When the local end sends out FIN to actively close, it may not receive a response from the server, so the local end may continue to maintain the FIN_WAIT_2 state, and the peer end will also be in the CLOSE WAIT state for a long time. This state Will be maintained until the application closes the connection. If there are too many connections in this state in the system, a large amount of connection resources will be wasted, thereby affecting the transmission performance of the system. At present, in order to avoid this situation, the FIN_WAIT_2 timer is set for the TCP connection. If the application on the local end performs an active shutdown for full shutdown, start the timer. The first time is set to 10 minutes. If 10 minutes If there is no message that the peer closes the connection is received, reset the timer to 75 seconds. If the message that the peer closes the connection is not received after 75 seconds expires, the local end will complete the operation of closing the connection by itself and release the corresponding resources. .

It can be seen from the above prior art that the first time-out time and the second time-out time of the FIN_WAIT_2 timer are both set to fixed time values, which cannot be adjusted by the user according to actual needs. For example, sometimes in order to prevent an attacker from consuming system resources by establishing a large number of such semi-connections in a short period of time, it is necessary to make such semi-connections disappear in a short period of time, but the existing technology cannot meet this technical requirement.

Contents of the invention

The purpose of the present invention is to provide a method for setting the waiting time for full closing of transmission control protocol connections, so that users can set the full closing waiting time of TCP connections through command line configuration as required, that is, the value of the FIN_WAIT_2 timer.

The purpose of the present invention is achieved in that the setting method of transmission control protocol connection full closing waiting time comprises:

a. The client sends a FIN (close connection request) to actively close;

b. After the client receives the confirmation from the server, the client enters the FIN_WAIT_2 (full close waiting) state;

c. The client starts the FIN_WAIT_2 timer and provides a configuration management interface for the transmission control protocol connection full close waiting time variable;

d. The client invokes the transmission control protocol connection full-close waiting time variable through the configuration management interface, and sets a corresponding time value for the variable as the transmission control protocol connection full-close waiting time value;

e. The client closes the connection and releases the corresponding resources.

The step c further includes setting an initial default value for the waiting time variable of TCP connection full close.

The waiting time for all TCP connections to be closed is the sum of the two timeout times, that is, the sum of the first timeout time and the second timeout time. The second timeout time value is fixedly set to 75 seconds.

The value assignment range of the TCP connection full close waiting time variable is 76-3600 seconds.

Described step d comprises:

d1. The client determines that it is necessary to set the waiting time for full closing of the transmission control protocol connection, and determines the corresponding waiting time value for full closing;

d2. The client invokes the TCP connection full-close waiting time variable through the configuration management interface, and assigns the determined full-close waiting time value to the variable as the TCP connection full-close waiting time value.

As can be seen from the above-mentioned technical scheme, the present invention adopts variable control based on the value of the FIN_WAIT_2 timer of the TCP connection (that is, the transmission control protocol connection full close waiting time value), and the user can configure the value of the variable through the command line, so as to achieve The purpose of configuring the FIN_WAIT_2 timer value. The invention changes the disadvantage that the value of the existing timer is controlled by a macro and cannot be easily changed, and can conveniently and flexibly meet some special needs of users. Moreover, in the present invention, the configuration of the FIN WAIT 2 timer value can be carried out very conveniently as required, thereby effectively avoiding the assailant from establishing a large number of semi-connections in a short time to consume the connection resources of the system.

Description of drawings

Figure 1 is a schematic diagram of the establishment and termination of a TCP connection:

Fig. 2 is a flow chart of the specific implementation of the present invention.

Detailed ways

Referring to Fig. 2 for the specific implementation of the setting method of the transmission control protocol connection full closing waiting time of the present invention, narrate as follows:

Step 1: The original macro will no longer be used to represent the value of the TCP connection full close waiting time timer, but will be represented by a variable, that is, the TCP connection full close waiting time variable will be established, and the TCP The connection full close waiting time variable sets the initialization default value. If the base initialization default value can be set to 10 minutes, the waiting time when the transmission control protocol connection enters the full close waiting state is 10 minutes;

After the transmission control protocol connection full close waiting time variable is established, the variable can be called as required, and the corresponding time value can be set for the variable;

The waiting time for all TCP connections to be closed is the sum of the two timeouts, that is, the sum of the first timeout and the second timeout; the second timeout is fixed at 75 seconds; The assignment range of the time variable is 76-3600 seconds; that is, when the user configures it as 76 seconds, it means that the first timeout of the timer is 1 second; the default configuration is 675 seconds, that is, the first timeout time is 10 minutes;

Step 2: Determine the need to set the waiting time for full closing of the transmission control protocol connection, and determine the corresponding waiting time value for full closing;

Step 3: calling the TCP connection full-close waiting time variable, and assigning the determined full-close waiting time value to the variable as the TCP connection full-close waiting time value;

That is: through the configuration management plane, provide the user with a transmission control protocol connection full close waiting time setting command: tcp finwait-time time_value, where "time_value" is the value configured by the user, and the value range is 76-3600 seconds; this command can Change the value of the variable to the "time_value" value. In this way, each time the transmission control protocol connection is fully closed waiting time state is entered, the waiting time for closing the connection is the "time_value" value.

Claims (6)

1, the establishing method of a kind of completely closing transmission control procotol connection stand-by period comprises:

A, client are sent and are closed connection request and carry out active and close;

After b, client were received the affirmation of server end, client entered into the contract fully wait state;

C, client terminal start-up contract fully waiting timer provide the configuration management interface of completely closing transmission control procotol connection stand-by period variable;

D, client are called completely closing transmission control procotol connection stand-by period variable by described configuration management interface, and are the corresponding time value of this specification of variables, as the completely closing transmission control procotol connection latency value;

E, client are finished and are closed connection, and discharge respective resources.

2, the establishing method of completely closing transmission control procotol connection stand-by period according to claim 1 is characterized in that: described step c also is included as completely closing transmission control procotol connection stand-by period specification of variables initialization default value.

3, the establishing method of completely closing transmission control procotol connection stand-by period according to claim 1, it is characterized in that the described completely closing transmission control procotol connection stand-by period is twice time-out time sum, i.e. time-out time and time-out time sum for the first time for the second time.

4, the establishing method of completely closing transmission control procotol connection stand-by period according to claim 3, it is characterized in that described second time the time-out time value to fixedly install be 75 seconds.

5, the establishing method of completely closing transmission control procotol connection stand-by period according to claim 4, the assignment scope that it is characterized in that described completely closing transmission control procotol connection stand-by period variable are 76-3600 second.

6, the establishing method of completely closing transmission control procotol connection stand-by period according to claim 1 and 2 is characterized in that described steps d comprises:

D1, client are determined to carry out the setting of completely closing transmission control procotol connection stand-by period, and determine corresponding contract fully latency value;

D2, client are called described completely closing transmission control procotol connection stand-by period variable by described configuration management interface, and the contract fully latency value of determining is composed to this variable, as the completely closing transmission control procotol connection latency value.