JP2003108450A - Terminal device with increased use efficiency of tcp/ip ports, and connection processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal device capable of reducing a port usage efficiency even if an application frequently using a transmitting port within a short time is used in an environment corresponding to a fire wall, and a connection processing method. SOLUTION: In this terminal device 1 used for TCP/IP communication, a port number information storage part 16 comprises a use port number processing frequency counting part 15 pre-storing MSL time elapse information on individual explicit use port number and block information ranging from 1st to nth (n: integer of n>1) when the port number use state information is considered as one block and counting the frequency of processing for detecting the usable port number by using the block information, and a port number detection processing frequency storage part 17 for storing the results of counting of the use port number processing frequency count part 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to TCP (Transmission Control Protocol) / IP (Inte
The present invention relates to a terminal device and a connection processing method for improving the TCP / IP port use efficiency in a terminal used by being connected to a network using the rnet Protocol), and in particular, the same port number is used until the maximum segment lifetime expires. The present invention relates to a technique of making a port number easy and fast when another port number is used because it cannot be used, and further explicitly determining the port number so as to be compatible with a firewall and the like.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional TC such as the Internet.
FIG. 6 is a diagram showing a packet flow at the time of communication connection and communication disconnection between a client device and a server device in a terminal connected to a network using a P / IP protocol and used.

In the case of FIG. 9, the client device and the server device are connected via the Internet, the client device serving as the local host is the transmitting side, and the server device serving as the remote host is the receiving side.

When starting a communication connection between the client device and the server device, first, a packet CS1 of a communication connection request (SYN) is sent from the client device to the server device.
Is output. A packet using the TCP / IP protocol has a port number at a transmission source (client device), a port number at a destination (server device), a sequence number assigned to each packet in sequence for each service, and the like. have.

The source port number is arbitrarily selected and determined from a plurality of candidates by software in the client device. The destination port number is a "well-known port number" corresponding to the communication service content or a port number defined by the communication protocol. The sequence number is a serial number indicating the order of the packet. For example, "1000" is given as the sequence number of the packet CS1.

Upon receiving the packet CS1, the server device enters a communication connection standby state and outputs a communication connection confirmation (ACK) packet SS1 as confirmation of the response. As the sequence number of the packet SS1, for example, "1001" which is obtained by adding 1 to the sequence number of the received packet is given.

Thereafter, the server device also outputs the communication connection request (SYN) packet SS2 to the client device. As the sequence number of the packet SS2,
For example, "2000" is given.

Upon receiving the packet SS2, the client device outputs a communication connection confirmation (ACK) packet CS2 as confirmation of the response. As the sequence number of the packet CS2, for example, "2001" which is obtained by adding 1 to the sequence number of the received packet is given.

When the server device receives the packet CS2, a communication connection between the client device and the server device is established, and thereafter, data and the like are transmitted and received by TCP / IP communication.

When the communication connection between the client device and the server device is terminated, first, the client device outputs a communication connection termination request (FIN) packet CS11 to the server device. For example, "1500" is given as the sequence number of the packet CS11.

Upon receiving the packet CS11, the server device enters a communication connection end standby state and outputs a communication connection confirmation (ACK) packet SS11 as a response confirmation.
As the sequence number of the packet SS11, for example,
"1" is added to the sequence number of the received packet
"01" is given.

Thereafter, the server device also sends a packet SS1 of a communication connection end request (SYN) to the client device.
2 is output. As the sequence number of the packet SS12, for example, "2400" is given.

Upon receiving the packet SS12, the client device outputs a communication connection confirmation (ACK) packet CS12 as confirmation of the response. As the sequence number of the packet CS12, for example, "2401" which is obtained by adding 1 to the sequence number of the received packet is given.

When the server device receives the packet CS12, the communication connection between the client device and the server device is terminated and the line is disconnected.

Here, the source port number included in each of the above-mentioned packets is arbitrarily selected from a plurality of candidates by software in the client device and is determined, so that it is almost never used explicitly. Absent. Therefore, the maximum segment lifetime (MSL) is set so that a plurality of packets sent from the client device to the Internet do not hold the same source port number, and the same source port number is set within 2 × MSL time. Is managed by the client device so that is not used.

The MSL time is IETF (Internet
RFC (Request for C), which was agreed by the Engineering Task Force as a standard contract of TCP / IP protocol.
omments) 793 document. Further, the segment in this case may be considered to be synonymous with the packet.

[0017]

With the spread of the Internet in recent years, criminal acts using the Internet have begun to occur, so that it is necessary to take security for the Internet line. For example, port numbers and other authentications are required. Firewalls that allow input to devices by numbers etc. have also become known.

However, as described above, generally, the source port number cannot be used for the firewall because it is arbitrarily selected from a plurality of candidates and determined. Generally, a firewall cannot determine whether an input packet should be passed unless some number is specified, so when using a port number, the port number of a series of packets is not specified. Need to be. However, at present, the port number is arbitrarily selected from multiple candidates, so if you try to make it explicit, it is necessary to explicitly specify all candidates, and the number of management targets increases and management is complicated. Turn into. On the contrary, since the security level is lowered by increasing the number of ports to be passed, it may be necessary to maintain the security level by increasing the regulation condition.

In order to prevent the number of management targets and the regulatory conditions from increasing, it is conceivable to explicitly manage the source port number by, for example, fixing it, but as described above, the same source port number is used. Since the number cannot be used within 2 × MSL time, it is inappropriate when the source port is frequently used within a short time. In other words, in the case of an application that frequently uses the source port within a short period of time in an environment that supports a firewall, it is not enough to explicitly set the source port.
Since it is necessary to update the source port number sequentially within the MSL time while clearly indicating the source port number, the method of simply fixing the source port number cannot be used. The case of frequently using the source port within a short time is a case of frequently using the same source port within a short time for exchanging voice information, such as an Internet telephone.

As described above, in an environment corresponding to a firewall, in the case of an application or the like that frequently uses a source port within a short time, the regulatory conditions are increased and complicated management is performed. The usage efficiency of the port was reduced.

The present invention has been made in order to solve the conventional problems as described above, and in the case of using an application that frequently uses a source port within a short time in an environment corresponding to a firewall. Even
An object of the present invention is to provide a terminal device and a connection processing method in which port usage efficiency is less likely to decrease.

[0022]

In order to achieve the above object, a terminal device having improved TCP / IP port use efficiency according to the present invention described in claim 1 is a service provided via the Internet. A port number information storage unit that stores port number information, a communication control unit that controls communication with the Internet, a communication interface unit that mutually converts internal signals and communication signals for communication with the Internet, and the same port A terminal device used for TCP / IP communication for measuring a maximum segment lifetime (MSL) for use, wherein the port number information storage unit includes MSL elapsed time information regarding individual explicit use port numbers, and a port. The number usage status information is regarded as one block, and the block information from the 1st to the nth (n: an integer of n> 1) is previously set. The used port number processing number counting section for storing the number of times of processing for detecting the usable port number using the block information, and the port number detection processing for storing the counting result of the used port number processing number counting section It is characterized by comprising a number-of-times storage unit.

The TCP of the present invention as defined in claim 2
The connection processing method that improves the port usage efficiency of / IP is
The MSL time elapsed information relating to the individual explicitly used port number and the port number usage status information are set as one block in advance, and block information from the 1st to the nth (n: n> 1 is an integer) is stored in advance. A connection processing method using a connected terminal device, which comprises sequentially detecting available port numbers using block information, and connecting processing with a partner using the detected port numbers. Characterized by having a step of starting.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments.

FIG. 1 is a diagram showing an external environment in which the terminal device of the first embodiment of the present invention is used.

In FIG. 1, the client device 1 and the server device 3, which are terminal devices, are connected to the Internet 2. When the client device 1 and the server device 3 establish a communication connection, they are connected via the Internet 2. Similarly, the client device 4 and
5 is also connected to the Internet 2, and the server device 3
And a communication connection can be implemented. The communication connection between the client devices may be performed via the server device 3 or may be directly performed between the client devices.

FIG. 2 is a block diagram showing a main part of the client apparatus 1 of FIG. 1 relating to the present embodiment.

The client device 1 is internally processed with the communication interface unit 11 by converting an internal signal into a signal suitable for communication and sending it out, or by converting a received communication signal into a signal which can be processed internally. Memory for storing programs and data necessary for communication connection between the communication control unit 12 that controls the transmission of signals from the Internet 2 or the reception of signals from the Internet 2 and the communication connection between the server device 3 and other client devices 4 or 5 and the like. Section 13, a timekeeping section 14 for timing the maximum segment lifetime (MSL) to use the same port, and an MSL for each port number used.
It has a used port number processing number counting unit 15 that counts the number of times of processing for detecting an available port number using time elapsed information and block information described later.

The storage unit 13 includes a port number information storage unit 16 for storing port number information of services provided via the Internet, and a used port number processing frequency counting unit 1.
The port number detection processing number storage unit 17 for storing the counting result of 5 is provided.

Further, the port number information storage unit 16 stores MSL time elapsed information regarding individual explicitly used port numbers,
Also, the port number usage status information is regarded as one block, and the block information from the 1st to the nth (n: n> 1 integer) is stored in advance. This n is set to a number that can supply the blocked explicit port number in sequence during 2 MSL time.

FIG. 3 is a diagram showing the structure of a general packet used also in this embodiment.

For the packetized data, a TCP header used in TCP (Transmission Control Protocol) for setting a bidirectional communication connection between a wide variety of two devices (systems) and a relatively high reliability. IP (I that provides communication services using packets in the network
An IP header used in the Internet Protocol) is added. Furthermore, a header (a header attached in the data link layer) for ensuring data transmission between the communication nodes is added to each packet at the time of communication.

The TCP header has various information and error detection information (checksum) in addition to the above-mentioned source port number, destination port number and sequence number.

FIG. 4 is a diagram showing classification of port numbers used in TCP / IP.

The first category is the well-known port number (W
ell-known port number)
0 to 1023 are assigned. This port number is assigned and often used for a specific service that can be used only on the root side or the system side, and many of them are famous.

The second category is the reserved port number (Reg
1 is the port number called "istered Port Number"
024 to 49151 are assigned. This port number is assigned to a company or the like so that a normal user can use it.

The third category is a port number called "Dynamic and / or Private Port Number", which is assigned 49152 to 65535. This port number is assigned as a freely usable number.

FIG. 5 shows the port number information storage unit 16 of FIG.
5 is a diagram showing a combination block of TCP / IP port number information of the present embodiment stored in FIG.

The first block (a1) contains the first port number information (a1) corresponding to the classification shown in FIG.
-1), the first port number usage status information (a1-) indicating whether or not the port numbers of (a1-1) are in use
2), the first 2MSL time elapsed information (a indicating whether or not the time is up to 2MSL time after the connection disconnection procedure of the port number of (a1-1) is performed.
1-3) is stored.

Similarly, in the second block (a2), second used port number information (a2-1), (a2)
-1) Second port number usage status information (a1-2), (a2-1) indicating whether or not the port number is in use
The second 2MSL time elapsed information (a2-3) indicating the information indicating whether or not up to 2MSL time has elapsed after the connection disconnection procedure of the port number of 1 is stored.

In this way, information is sequentially stored in each block, and the n-th block (an) has the n-th port number information (an-1) and the port number of (an-1). 2MS after the procedure of disconnecting the connection of the n-th port number usage status information (an-2) and (an-1) indicating whether or not is being used
The n-th 2MSL time elapsed information (an-3) indicating whether or not the time is up to L time is stored. Figure 6
2 is an operation flowchart when the client device 1 of FIG. 1 according to the present embodiment starts communication connection processing with the server device 3.

First, the detection processing number N set in the used port number detection processing number coefficient section 15 of the client device 1 is set to 1 (S1). The communication control unit 12 determines whether or not the number of times N of detection processing is less than or equal to the total number n of combined blocks of TCP / IP port number information (S).
2). At that time, the number of times of detection processing N is stored in the port number detection processing frequency storage unit 17.

When the number of times N of detection processing is less than or equal to the total number n of combined blocks (S2: YES), it is determined whether the port number usage status information (an-2) of the Nth block is unused. Is carried out (S3). If the number N of detection processes is greater than the total number n of combined blocks (S2: NO), it is determined that the connection has failed.

When the port number use status information (an-2) of the Nth block is unused (S3: YES), N
It is determined whether or not the 2MSL time elapsed information (aN-3) of the th block is "0" (S4). When the port number use status information (an-2) of the Nth block is in use (S3: NO), “1” is added to N indicating the number of the combination block (N = N + 1) ( From S5), it is again determined whether or not the number N of times of detection processing is equal to or less than the total number n of the combined blocks of the TCP / IP port number information (S2).

When the 2MSL time elapsed information (aN-3) of the Nth block is "0" (S4: YES), the communication control unit 12 stores the Nth block in the port number information storage unit 16. Port number usage information (a)
N-2) is changed to being used (S6), the connection process with the server device is started using the used port number information (aN-1) of the Nth block (S7), and the process is ended.

When the 2MSL time elapsed information (aN-3) of the Nth block is not "0" (S4: NO), N = N + 1 is set (S5) as in the case of (S3: NO). Therefore, the determination of N ≦ n (S2) is performed again.

FIG. 7 is an operation flowchart when the client device 1 of FIG. 1 according to the present embodiment ends the communication connection process with the server device 3.

First, the communication control unit 1 of the client device 1
2 changes the port number usage status information (aN-2) of the Nth block stored in the port number information storage unit 16 to unused (S11), and the 2MSL time elapsed information (aN-3) of the Nth block. To 2MSL time (S
12), the process ends.

FIG. 8 is an operation flowchart when the client device 1 of FIG. 1 according to the present embodiment carries out the 2MSL time change process.

First, the communication controller 1 of the client device 1
For No. 2, it is determined whether the 2MSL time elapsed information (aN-3) of the Nth block stored in the port number information storage unit 16 is "0" (S21). When 2MSL time elapsed information (aN-3) is "0" (S21:
If YES, the process ends. When the 2MSL time elapsed information (aN-3) is not "0" (S21: NO), the 2MSL time elapsed information (aN-) of the Nth block.
Change the storage content of 3) to "(aN-3) -1" (S
22) and the process ends.

Thus, in this embodiment, 2MSL is used.
Since explicit port numbers can be supplied sequentially from the blocked memory contents during the passage of time, it is possible to suppress an increase in the used port numbers to be managed during communication control, minimize management complexity, and regulate conditions. In an environment that supports a firewall that uses port numbers without increasing
Even when using an application that frequently uses the source port within a short period of time, it is possible to reduce deterioration in port usage efficiency.

In the present embodiment, the case where the client device 1 is connected to the server device 3 via the Internet 2 for communication is shown, but the present invention is not limited to this. For example, the client device 4 may be connected to the Internet. The present invention can be applied to any case where communication is performed between terminals using TCP / IP, such as a case where communication connection is made with the client device 5 via 2, or a case where communication connection is made directly with the client device 5 from the server device 3. it can.

Especially in voice communication using the Internet, since an operation close to that of a telephone is required, the same TC
It is expected that the P / IP port will be frequently used within a short time, and since it is a conversation application,
The present invention is effective because a seamless environment between the inside of the LAN and the Internet is required and a firewall is also required.

Further, each port number defined in FIG.
It is expected to increase in the future, but in that case, the port number currently used freely as a dynamic / private port may be defined as a well-known port number or a reserved port number. have. In that case, the conventional method requires complicated changes,
According to the method of the present invention, only the block shown in FIG. 5 needs to be added, so that the changing process when updating the port number becomes easy.

In the above embodiment, TCP / I
The case where the port number is used for the firewall in the P protocol environment has been described, but the present invention is not limited to this. For example, UDP (User Datagram Protoco).
l) / It can be applied even when the port number is used for the firewall in the IP protocol environment.

[0056]

As described above, according to the present invention, it is possible to suppress an increase in the used port number to be managed at the time of communication control, to minimize the complication of management, and to increase the port number without increasing the regulation condition. Even if you are using an application that frequently uses the source port within a short time in an environment that supports a firewall that uses Internet Explorer, use a terminal device that reduces the decrease in port usage efficiency and a connection processing method. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an external environment in which a terminal device according to a first embodiment of the present invention is used.

FIG. 2 is a block diagram showing a main part relating to the present embodiment in the client device of FIG.

FIG. 3 is a diagram showing a configuration of a general packet used also in this embodiment.

FIG. 4 is a diagram showing classification of port numbers used in TCP / IP.

5 is a diagram showing a combination block of TCP / IP port number information of the present embodiment stored in the port number information storage unit of FIG.

FIG. 6 is an operation flowchart when the client device of FIG. 1 according to the present embodiment starts a communication connection process with a server device.

FIG. 7 is an operation flowchart when the client device of FIG. 1 according to the present embodiment ends the communication connection process with the server device.

FIG. 8 is an operation flowchart when the client device of FIG. 1 according to the present embodiment performs a 2MSL time change process.

FIG. 9 is a diagram showing a packet flow at the time of communication connection and communication disconnection between a client device and a server device.

[Explanation of symbols]

1 client device, 2 internet, 11
Communication interface section, 12 Communication control section, 1
3 storage section, 14 clock section, 15 used port number detection processing number counting section, 16 port number information storage section,
17 Port number detection processing count storage unit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Naito             Gunma Prefecture Takasaki City Futabacho 3-1 Oki Co., Ltd.             Information Systems F term (reference) 5B089 GA11 GA21 GB01 HA10 HB02                       KA05                 5K030 GA04 GA15 HA08 HB01 HD03                       HD06                 5K034 AA02 AA19 DD02 FF13 HH65                       LL01 MM39

Claims (2)

[Claims] 1. A port number information storage unit for storing port number information of a service provided via the Internet, and a communication control unit for controlling communication with the Internet.
Communication interface part that mutually converts internal signals and communication signals for communication with the Internet, and maximum segment lifetime (MSL) to use the same port
A terminal device used for TCP / IP communication for timekeeping, wherein the port number information storage unit includes MSL time elapsed information regarding individual explicitly used port numbers and port number usage status information as one block, Used port number processing number counting unit that stores in advance block information from the 1st to the nth (n: integer of n> 1), and counts the number of processes for detecting an available port number using the block information And a port number detection processing number storage section for storing a counting result of the used port number processing number counting section, wherein a terminal device with improved TCP / IP port use efficiency is provided. 2. The MSL time elapsed information regarding individual explicitly used port numbers and the port number usage status information are set as one block in advance, and the 1st to nth (n: n)
Block number up to 1) is stored, and a connection processing method using a terminal device connected to the Internet, the step of sequentially detecting available port numbers using the block information, TCP / I, characterized in that it has a step of starting a connection process with the other party by using the established port number.
A connection processing method that improves the port usage efficiency of P.