JPH0730575A - Router having address conversion function - Google Patents

Abstract

PURPOSE:To form a router able to be used even when a formal address and an informal address are in coexistence and to reduce a time for table retrieval. CONSTITUTION:When the router 1 receives a packet from a network, an address analysis mechanism 21 retrieves an address allocation table 31 as to an address extracted from a packet to convert the address and sends the result to a destination network. When the address is not registered in the address allocation table 31, an address conversion rule table 32 is referred to and a corresponding address pair is registered to the address allocation table 31 to make address conversion. Furthermore, the address is allocated by an address group by registering a group address to the address conversion rule table 32. Moreover, the router is provided with an in-data address conversion mechanism 38 and a data pattern registration table 35 or the like to convert the address included in a packet data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a router having a function of connecting a plurality of networks and converting an address of a source or a destination of a packet passing therethrough. The present invention relates to a router having an address translation function for allocating address pairs of.

[0002]

2. Description of the Related Art A router device with an address conversion function effectively uses the few official addresses that can be connected to the Internet. Therefore, when many machines with unofficial addresses connect to the Internet, they are converted to official addresses before connecting. As such a router, for example, the router disclosed in Japanese Patent Application No. 4-150295 has been proposed.

The address translation method in the above-mentioned conventional router uses a real machine address (unofficial address),
Register a pair of virtual machine addresses (official addresses) in the one-to-one address conversion table and convert according to it,
The method not registered in the address conversion table was a method of simply allocating addresses in order and registering them in the address conversion table.

[0004]

By the way, the above-mentioned conventional router has the following problems. Since the table that registers the address pairs to be translated and the table that registers the address pairs that are actually communicating are together, define a rule such as which address is translated and which address is not translated. Can not.

As a result, during communication between the network on one side of the router and the network on the other side, the addresses of all the packets are translated, and it is not necessary to translate them. Even with an address
In practice, it could not be used in a place where both official and unofficial addresses were mixed on one side of the router, such as assigning a new address to the official address.

Similarly, since there is only one table, all address pairs that are not actually communicating are registered, so it takes time to search the table when translating addresses of machines that are communicating. There was a problem. Since the address pairs to be translated are registered one-on-one, the amount of registration is large when the scale of the network is large, there is a problem that registration takes too long and the address translation table becomes too large. Since only the address in the header of the packet is rewritten and the address information contained in the data cannot be rewritten, an application that puts the address in the data and communicates could not communicate well.

The present invention has been made in consideration of the above-mentioned problems of the prior art, and the first object of the present invention is to use it even in a place where a formal address and an unofficial address are mixed. It is another object of the present invention to provide a router capable of reducing the table for address translation and shortening the time for table lookup. Second of the present invention
The purpose of is to provide a router that can shorten the registration time in the table for address translation.

A third object of the present invention is to provide a router capable of rewriting address information contained in packet data.

[0009]

FIG. 1 is a diagram for explaining the principle of the present invention. In the figure, 1 is a router, 21 is an address analysis mechanism that analyzes an input address and replaces the addresses if necessary, 22 is an address generation mechanism that generates a pair of a formal address and an unofficial address, and 31 is actually performing communication. Address table which stores the pair of unofficial machine address and official machine address of the machine in the state of being in the state, 32 is the address translation rule table which stores the rule for generating the address, 33 is the official address group and the unofficial address Group address registration means for registering a pair of groups, 34 an address determination unit for determining whether the received packet corresponds to the registered group address, 35 a data pattern registration table for registering a packet data pattern, and 36 a A data pattern extraction unit for extracting a data pattern from the received packet, 37 is a registered pattern Data pattern comparison unit for comparing the extracted pattern data in the address conversion mechanism for converting the address of the received packet 38, 3
An address conversion timing unit 9 determines the timing of address replacement.

In order to solve the above problems, the invention of claim 1 of the present invention, as shown in FIG. 1, uses an address conversion table for registering a pair of an unofficial address and an official address, and a transmitted packet. Regarding the retrieved address,
In the router having the address conversion function, which is provided with the address analysis mechanism 21 for converting an unofficial address to a formal address and an official address to an unofficial address with reference to the address translation table, the address translation table is unofficial. The address conversion rule table 32 for registering the correspondence between the addresses and the formal addresses, and the address allocation table 31 for storing the pair of the unofficial address and the formal address of the machine in the actual communication state are provided. The address analysis mechanism 21 translates the address extracted from the packet transmitted based on the address pair registered in the address assignment table 31 and the address translation rule table 32.

According to a second aspect of the present invention, in the first aspect of the invention, an address conversion timing unit 39 for determining the timing of converting the packet address is provided. According to a third aspect of the present invention, in the first or second aspect of the invention, a group address registration means 33 for registering an address group of a machine or a network,
An address determination unit 34 for determining whether or not the address in the passing packet corresponds to the group address.

The invention of claim 4 of the present invention is the same as claims 1 and 2.
Alternatively, in the invention of claim 3, a data pattern registration table 35 for registering the data position in the data part or the header part of the received packet, the data pattern, and the position in the packet of the address to be converted when the pattern is matched. And a data pattern extraction unit 36 that cuts out data from the received packet based on the position information of the data pattern registered in the data pattern registration table 35, a pattern registered in the data pattern registration table 35, and a data pattern extraction unit. The data pattern comparison unit 37 that compares the data cut out from the actual packet by 36, and the in-data address that rewrites the contents of the address position registered in the data pattern registration table 35 when the comparison result in the data pattern comparison unit 37 is the same. And a conversion mechanism 38.

[0013]

In FIG. 1, first, a pair of an unofficial address and a formal address is registered in the address conversion rule table 32 in advance. When the router 1 receives the packet from the network A or B, the address analysis mechanism 21 searches the address allocation table 31 for the address extracted from the packet. If there is a corresponding address, the address is converted based on the address allocation table 31, and the packet with the converted address is transmitted to the destination network.

When the address is not registered in the address allocation table 31, the source address of the received packet is an unofficial address (real address), or the destination address is a formal address (virtual address). At this time, the address generation mechanism 22 refers to the address conversion rule table 32. Then, if the address pair including the corresponding address is registered, the corresponding address pair is registered in the address allocation table 31, and the address analysis mechanism 21 converts the address of the received packet. If not registered, address conversion is not performed, and normal packet processing is performed using the original address.

The address translation timing unit 39 is provided to determine the timing of reassigning the address of the packet. When the packet is passed to the address analysis mechanism 32 immediately after the router 1 receives the packet and immediately before sending it, The address analysis mechanism 32 passes the address to the address conversion timing unit 39. The address conversion timing unit 39 instructs the address analysis mechanism on the conversion timing of the received address. When the source address is an unofficial real address, the address is converted to the official virtual address immediately before sending, and when the destination address is the official virtual address,
Immediately after receiving it, it is converted to an unofficial real address.

Further, the group address registration means 33 and the address determination section 34 are provided for performing address conversion based on the formal real address group and the formal virtual address group registered in the address conversion rule table 32. The group address registration means 33 registers the above-mentioned unofficial real address group and formal virtual address group in the address conversion rule table 32.

Then, when the address generation mechanism 22 refers to the address conversion rule table 32, the address judgment unit 34 judges whether or not the received unofficial address is registered as an unofficial address group and is registered. In this case, the address is assigned from the pair of official virtual addresses. Further, the in-data address conversion mechanism 38, the data pattern registration table 35, the data pattern comparison unit 37, and the data pattern extraction unit 36 are provided for converting the address included in the data of the packet. In the table 35, the data pattern in the packet that sufficiently expresses the characteristics of the packet of the application that includes the IP address in the data of the packet and the position of the address to be converted are registered in advance.

When the router 1 receives the packet, the data pattern extraction unit 3 according to the data pattern registration table 35.
At 6, the data pattern is cut out from the packet. Then, in the data pattern comparison unit 37, the cut-out data pattern is compared with the one registered in the data pattern registration table 35, and if they are equal, the in-data address conversion mechanism 38 stores the data pattern in the data pattern registration table 35. The address in the packet is rewritten according to the registered information.

In the invention of claim 1 of the present invention, as described above, the address allocation table 31 and the address conversion rule table 3 are provided.
2, the address allocation table 31 and the address conversion rule table 3 are provided.
Since the address extracted from the packet sent based on the address pair registered in 2 is translated, it can be used even in the place where the real address and virtual address are mixed in the network on one side of the router. Also, since the address pair not actually communicating is not registered in the address allocation table, the address allocation table does not become large and the time for table search can be shortened as compared with the conventional one.

In the second aspect of the present invention, the address conversion timing unit 39 is provided as described above, and all the processing can be performed by the existing address in the router 1. You can use the original functions as they are and simplify the router configuration. In the invention of claim 3 of the present invention, as described above, the group address registration means 33 and the address determination section 3 are provided.
4 is provided so that the group address can be registered in the address conversion rule table 32, the table to be registered does not become large even when the scale of the network is large, and all addresses need to be registered one to one. Since there is no such thing, the registration time in the table can be shortened.

According to the fourth aspect of the present invention, since the in-data address translation mechanism 38, the data pattern registration table 35, the data pattern comparison unit 37, and the data pattern extraction unit 36 are provided as described above, the IP packet Not only the address in the header but also the address included in the data can be rewritten.

[0022]

FIG. 2 is a diagram showing a first embodiment of the present invention. In the figure, 2 is a network A that communicates using addresses including unofficial addresses (hereinafter referred to as real addresses), 1 is a router having an address conversion function, 3
Is a network B that communicates using a formal address (hereinafter referred to as a virtual address).

In the router 1, 11 and 12 are networks for controlling communication between the network and the router 1.
The interface unit 13 is a routing unit that determines the destination interface of the received packet. Two
3 is an address translation / registration mechanism. In the address translation / registration mechanism 23, 21 is an address analysis mechanism for extracting a destination address included in a packet and checking whether or not there is an address that needs translation. 31 is a real address and a virtual address. An address allocation table composed of one-to-one pairs, 22 is an address generation mechanism for generating an address to be converted by collating the following address conversion rule table when the address is not registered in the address allocation table, 32 Is an address translation rule table in which addresses to be translated are registered.

In the configuration diagram shown below, the solid arrow means "packet flow", the dotted arrow means "reference", the thick solid arrow means "control flow", and the thick dotted arrow means "write". There is. FIG. 3 is a diagram showing an outline of the structure of an IP packet flowing in an IP (Internet Protocol) network. As shown in the figure, in the IP packet, 4 bytes from the position of the 13th byte from the beginning of the packet The source address and the next 4 bytes are the destination address (RFC791 Internet Protocol, Dar
paInternet Program, Protocol Specification, Septembe
r 1981).

FIG. 4 is a diagram showing an example of the address allocation table 31 described above. As shown in FIG.
A pair of real address and virtual address is registered in.
FIG. 5 is a diagram showing an example of the above-mentioned address translation rule table 32. As shown in FIG. 5, all the pairs of real addresses and virtual addresses to be subjected to address translation are registered in the address translation rule table 32. ing.

Next, the operation of this embodiment shown in FIG. 2 will be described. In normal router operation, the IP packet (FIG. 3) sent from network A or network B
The received IP packet is received by the network interface unit A or the network interface unit B, and is then transmitted to the network A or the network B from the determined interface unit after the routing unit 13 determines the destination interface.

In the above router operation, in this embodiment, address conversion is performed by the processing shown in the flowcharts of FIGS. FIG. 6 is a flow chart showing the address conversion process in this embodiment. The IP packet sent from the network A which communicates with an address including a real address or the network B which communicates with a virtual address is the network of the router 1.・ Interface A
Or, it is received by B. The received IP packet is subjected to input processing and then sent to the address analysis mechanism 21 of the address translation registration mechanism 23.
The address included in the P packet is extracted (step S1 in FIG. 6).

Next, the address analysis mechanism 21 collates the address allocation table 31 (step S2) and checks whether or not the fetched address is an address to be translated (step S3). As shown in FIG. 4, a pair of a real address and a virtual address that actually exist is registered in the address allocation table 31, and the address analysis mechanism 21 collates the fetched address with the address allocation table 31 to determine the source address. Is registered as a real address, the corresponding virtual address is fetched from the address allocation table 31, and the source address part of the IP packet is rewritten to the virtual address (step S4).

When the destination address is registered as a virtual address, the real address in the address allocation table is taken out and the destination address part of the IP packet is rewritten to the real address. Then, the checksum is recalculated (step S5) and passed to the output process (step S5).
10) The packet is transmitted (step S11). Furthermore, when the source address and the destination address are not registered in the address allocation table 31, the address conversion rule table 32 shown in FIG. 5 is checked to see if the address is in the address conversion rule table 32. Check (step S6
7).

FIG. 7 is a flowchart of the address conversion rule table search process. The address conversion rule table search process will be described with reference to FIG. In step R1, the first row of the address translation rule table is taken out, and in step R2 it is checked whether or not the source address is equal to the real address. If they are equal, then go to step R3,
The real address and virtual address of the corresponding line are returned, and the search ends.

If the source address is not equal to the real address, the process goes to step R4 to check whether or not there is the next row in the address translation table. If there is, the next address in the address translation rule table is checked. The row is taken out and the process returns to step R2.
If not, the search process ends. As a result of searching the address conversion rule table 32 as described above, if the source address is registered as a real address, or
If the destination address is registered as a virtual address, it is an address to be translated. In this case, the address generation mechanism 22 generates a virtual address from the real address or a real address from the virtual address according to the contents registered in the address conversion rule table 32, and registers it in the address allocation table 31. Also, the address conversion rule table 3
If the address of the received packet is not registered in 2 as well, there is no need to convert the address, so the IP packet will be processed with the normal source and destination addresses of the router. To do.

That is, in the flow chart of FIG. 6, the address of the received packet is the address translation rule table 32.
If (step S7), the address generation mechanism 22 generates an address pair based on the search result of the address conversion rule table 32 (step S8), and registers it in the address allocation table 31 (step S9). The process proceeds to S4 and the above-mentioned processing is performed.

If the address of the received packet is not in the address conversion rule table 32, the above-mentioned normal output processing is performed (step S10). After the address of the IP packet is converted as described above, the IP packet is delivered to the network interface A or B and transmitted to the network A or B. Also, the address allocation table 31
Is cleared, for example, when communication between networks ends and there is no access for a predetermined time or more, and when communication between networks starts, a real address and a virtual address are newly registered.

In this embodiment, since the address allocation table and the address conversion rule table are provided as described above, it can be used even in a place where a real address and a virtual address are mixed in the network on one side of the router. Yes, again
Since the address pair not actually communicating is not registered in the address allocation table, the address allocation table does not become large, and the time for table search can be shortened as compared with the conventional one.

FIG. 8 is a diagram showing a second embodiment of the present invention. In this embodiment, an address conversion timing section 39 for determining the address conversion timing is provided in the first embodiment. Other configurations are similar to those of the first embodiment shown in FIG. In the present embodiment, all the processing is performed in the router 1 by using an existing address, so that the function originally possessed by the router can be used as much as possible and the configuration of the router is simplified. .

FIG. 9 is a diagram showing the flow of processing in this embodiment. In this embodiment, as shown in the figure, processing is performed with a real address in the router 1. That is, when the router 1 receives a packet from the network A through the network interface A, the real address is used as it is, the destination network is determined, normal packet processing such as checksum matching is performed, and then the address is converted. Send to network B via interface B. Also, router 1
When the packet is received from the network B via the network interface B, first, the virtual address is converted into the real address, and then the normal address is processed by the real address and the packet is transmitted to the network A via the network interface A.

FIGS. 10 and 11 are flowcharts showing the address rewriting process in the router of this embodiment. Here, the network A uses the unofficial address (real address) for communication, and the network B uses the official address. Use the network you are communicating with. Next, the processing of this embodiment will be described with reference to FIG.

The IP packet sent from the network A or the network B is received by the network interface unit A or B of the router 1, and input processing such as checksum verification is performed. (Step S1 in FIG. 10) Next, immediately after performing the input process, the packet address rewriting process (steps S1 to 9) is performed, and further, the forwarding process is performed by the routing unit 13.

Finally, immediately before the output process (step S19), the packet address rewriting process (steps S11 to S18) is performed again, and then the output process (step S19) is performed and the packet is transmitted (step S19). S
19). Here, the address rewriting process (steps S2 to 9 and steps S11 to 1) is performed immediately after the input process (step S1) and immediately before the output process (step S19).
The portion 8) includes the function of the address conversion timing unit 39.

In the packet sent from the network A using the unofficial real address, the source address is the unofficial address and the destination address is the official address. Therefore, the address immediately after the input process (step S1) is performed. In the judgment part (steps S3 and 7) of "whether the source address is registered as a virtual address" in the rewriting process (steps S2 to 9), the judgment result is always No, and the address is not rewritten. .

In the address rewriting process (S11-18) immediately before the output process (step S19), in the judgment part (steps S12 and 16) of "whether the source address is registered as a real address", the address to be rewritten If so, either condition is matched, and the address is rewritten if necessary. Further, in the packet sent from the network B using the formal address, since the source address is the formal address and the destination address is the formal address, the address rewriting process immediately after the input process (step S1) ( Step S2-
The judgment part of "whether the source address is registered as a virtual address" in 9) (steps S3 and S7)
Then, if it is an address to be rewritten, either condition is matched, and the address is rewritten as necessary.

In the judgment portion (steps S12 and 16) of "whether the source address is registered as a real address" in the address rewriting processing (steps S11 to 18) immediately before the output processing (step S19), the judgment result Is always No, and the address is not rewritten. The IP packet sent from the network A that communicates using an unofficial address is received by the network interface unit A of the router 1 and subjected to input processing such as checksum verification (step S1 in FIG. 10).
Before passing to the output processing via the routing unit 13,
It is passed to the address analysis mechanism 21.

The address analysis mechanism 21 takes out the source address contained in the IP packet, and checks by the address assignment table 31 whether the taken source address is a real address to be translated (step S11). The sender address and the address allocation table 31 are collated, and when the real address is registered (step S12), the address analysis mechanism 21 is instructed to rewrite the address. The address analysis mechanism 21 takes out the virtual address of the address allocation table 31 and rewrites the source address of the IP packet with the virtual address (step S13).

Further, the source address is the address allocation table 3
If it is not 1, it is checked whether it is in the address conversion rule table 32 (steps S15 and S16). If it is in the address conversion rule table 32, the address generation mechanism 22 generates a virtual address from the real address according to the contents registered in the address conversion rule table 32 (step S17).
The real address and the virtual address are registered in the address allocation table 31 (step S18), and the address conversion is performed (step S13). When the address conversion is performed, the checksum is recalculated (step S14) and passed to the output process.

If the address of the received packet is not registered in the address translation rule table 32, it is not necessary to translate the address. Therefore, the IP packet has the original source and destination addresses. Normal router IP
Process packets. Then, after output processing, it is passed to the network interface B for transmission. vice versa,
The IP packet sent from the network B that communicates using only the official address is received by the network interface unit B of the router 1, subjected to input processing such as checksum verification, and then temporarily passed to the address analysis mechanism 21. The address analysis mechanism 21 extracts the destination address included in the IP packet.

Next, the address allocation table 31 is searched in the same manner as the IP packet sent from the network A which communicates using an unofficial address (see FIG. 1).
If the address of the transmission destination exists in the address allocation table 31 (step S2 of 0) (step S3), the address analysis mechanism 21 is instructed to rewrite the address. The address analysis mechanism 21 converts the virtual address into a real address (step S4). Then, the checksum is recalculated (Fig. 1
0 in step S5), and is passed to the output processing via the routing unit 13 (step S19).

The destination address is the address assignment table 3
If it does not exist, the address translation rule table 32 is searched (steps S6 and 7), and if the destination address is in the address translation rule table 32, a real address is generated from the virtual address (step S8). ), Address assignment table 3
1 is registered (step S9), and the above-mentioned processing is performed. If the IP packet does not exist in the address translation rule table 32, the normal packet processing of the router is performed using the original source and destination addresses of the IP packet.

FIG. 12 is a diagram showing a third embodiment of the present invention. In the first and second embodiments, one real address and one virtual address are provided for each host, but in the present embodiment, in addition to this, a set of informal address groups (hereinafter referred to as A pair of a real address group) and a formal set of virtual addresses (hereinafter referred to as a virtual address group) is registered.

Therefore, in the present embodiment, the group address registration mechanism 3 for registering the pair of the real address group and the virtual address group in the address translation rule table 32 in the second embodiment.
3 and an address determining unit 34 for determining whether or not the real address and the virtual address are registered as a group address in the address conversion rule table 32. Other configurations are the same as those of the second example shown in FIG. It is similar to the embodiment.

FIG. 13 is a diagram showing an example of an address and an address group registered in the address translation conversion rule table 32. The address notation of this embodiment will be described with reference to FIG. <Example 1> This is a notation when a standard one-to-one address is assigned as shown in the first and second embodiments without using a group address. <Example 2> This is a notation when an arbitrary one of the machines in the specified range is connected to the outside.

In the figure, the real address group 126.0.0.2-
128 (in this case 126.0.0 is the network
Address, 2 to 128 are machine addresses), the network address is 126.0.0 and the real address in the machine address range 2-128 is associated with the virtual address 133.160.29.2. There is. In this case, when one machine is communicating, the second machine cannot be assigned an address. <Example 3> This is a notation when assigning to a specified address from a specified range of machines.

That is, the real address group 126.0.0.129-254
Shows that a real address in the range of 129-254 is assigned to a virtual address in the range of 133.160.29.3-15. In this case, when all the assigned addresses are in use, the new address cannot be assigned. <Example 4> A notation method for rewriting the network number is shown, and the same address as the real address is used as the machine address part of the virtual address to be assigned.

That is, when converting a real address to a virtual address, the machine address n is used as it is in the real address group 126.0.0.n, and the real address 126.0.0 is changed to 133.160.30. By rewriting, the real address is converted into a virtual address. <Example 5 to Example 6> A notation method for allocating to a specified address from a specified machine in a network in a specified range is shown.

That is, in Example 5, the machine with the machine address 1 in the range of network numbers 126.0.1 to 126.0.10 in the real address group is assigned to the addresses of 133.160.31.1 to 133.160.31.10 in the virtual address group. The case is shown. Further, in the example 6, in the real address group, the machine with the machine address 2 having the network number of 126.0.n has the virtual address of 133.160.3.
It shows the case of assigning to the 2.n address. <Example 7 to Example 12> An example is shown in which any one of the designated networks is assigned by reflecting the network number in the host number.

For example, in Example 7, in the real address group, an arbitrary machine (* means an arbitrary value) having a network number in the range of 126.0.1-10 is set as a virtual address group.
It shows the case of assigning to the addresses from 133.160.29.1 to 133.160.29.10. The same applies to Examples 8 to 12. FIG. 14 is a flow chart showing the processing in the address determination unit 34 in the present embodiment, and the address allocation using the group address in the present embodiment will be described with reference to the figure.

When the router 1 receives the IP packet sent from the network A which communicates with the address including the real address, the IP packet is sent to the address analysis mechanism 21 of the address translation registration mechanism 23, and the address analysis mechanism 21 receives the IP address. Fetch the real address contained in the packet. Next, the address analysis mechanism 21 collates the address allocation table 31 to check whether the fetched address is an address to be translated. The processing up to this point is the same as in the first and second embodiments.

Then, when there is no corresponding address in the address allocation table 31, the address conversion rule table 32 is referred to. At this time, the address determination unit 34 performs the processing shown in FIG. 14 and the received source address is the address translation rule table 3
It is determined whether the address is registered as a real address group in 2. In the flowchart of FIG. 14, in step S1, the first row of the address translation rule table 32 is fetched,
In step S2, it is determined whether the real address is in the group address notation, and if it is not in the group address notation, the process proceeds to step S3. In the case of the group address notation, the process goes to step S7.

Then, in step S3, it is determined whether or not the source address is equal to the real address. If they are equal, the process goes to step S4 to return the real address and virtual address of the corresponding line. If they are not equal, step S
5, it is determined whether or not there is a next row in the address translation rule table. If there is, the process goes to step S6 to take out the next row in the address translation rule table, and returns to step S2. If there is no next line in the address conversion rule table 32,
Finish the search.

If the real address is the group address notation in step S2, the process goes to step S7 to divide the address. That is, as shown in the figure, for example, when the real address is 126.0.20.2-128,
Divide like a = 126, b = 0, C = 20, d = 2-128. In step S8, the header address and the address of the table are compared only for the terms whose numbers are fixed (above b to c). If they do not match, the process proceeds to step S5 and the above processing is repeated.

If they match in step S8, the process goes to step S9 to determine the form of the term having a numerical range. Then, as shown in the figure, in the case of the XY format such as "2-128", the process proceeds to step S10, it is determined whether or not the source address is within the range, and if it is within the range, In step S13, the smallest address is assigned from the real address group and virtual address group in the corresponding row, and the process proceeds to step S14. If it is not within the range, go to step S5 and repeat the above-mentioned processing.

In step S14, step S13
It is determined whether or not the address assigned in is used. If it is already used, the process goes to step S5 to repeat the above process. If it has not been used, the search ends. When it is determined in step S9 that the format of the term having a range of numbers is the * format (example 7 to example 12 in FIG. 13), the process proceeds to step S11, where the real address group and the virtual address group of the corresponding row are selected. The minimum address is assigned, and the above processing is performed in step S14. If it is determined in step S9 that the form of the item having a range of numbers is the n form (examples 4 and 6 in FIG. 13), the process proceeds to step S12, where n in the corresponding line is the address in the header. The same thing as the above is put in and assigned, and the above processing is performed in step S14.

The determination process is performed as described above, and when the real address is registered in the address conversion rule table 32, the virtual address group forming a pair is allocated, and the address is allocated in the address allocation table 31. To register. Then, like the first and second embodiments described above, the corresponding address is retrieved from the address allocation table 31,
The address part of the IP packet is rewritten, the checksum is recalculated, and the packet is sent to the output process for packet transmission.

When the IP packet sent from the network B communicating with the virtual address is received by the router 1, the received IP packet is sent to the address analysis mechanism 21 of the address translation registration mechanism 23 and the The analysis mechanism 21 takes out the address contained in the IP packet. Next, the address analysis mechanism 21 uses the address allocation table 31.
Is checked to see if the fetched address is an address to be translated. The processing up to this point is the same as in the first and second embodiments.

Then, when there is no corresponding address in the address allocation table 31, the address conversion rule table 32 is referred to. At this time, the line registered as the group address is not referred to, and the same processing as in the first and second embodiments is performed.
That is, since the connected host cannot be specified from the informal real address group, the line registered as the group address is not referred to in this case.

In this embodiment, since the group address is registered in the address conversion rule table 32 as described above, the table to be registered does not become large even when the scale of the network is large, and Since it is not necessary to register all addresses on a one-to-one basis, registration time in the table can be shortened. FIG. 15 is a diagram showing the configuration of the fourth embodiment of the present invention. This embodiment is an embodiment in which the address within data can be converted in a special application in which the address is communicated within the data excluding the IP header. Shows.

Therefore, in this embodiment, the data pattern registration table 35, the data pattern extraction unit 36, the data pattern comparison unit 37, and the in-data address conversion mechanism 38 are provided in the third embodiment. The other configuration is the same as that of the third embodiment shown in FIG. FIG.
FIG. 3 is a diagram showing an example of the data pattern registration table, and as shown in the figure, in the data pattern registration table 35, there is a “search pointer” indicating the position information of the data pattern of the application to be converted, and at that position. “Data” indicating the data pattern and “address position” indicating the position in the data where the address is recorded are registered.

Next, address conversion in this embodiment will be described. When the IP packet sent from the network A that communicates with the address including the real address is received by the network interface unit A of the router 1, it is sent to the address analysis mechanism 21 of the address translation registration mechanism 23, and the address analysis mechanism 21 retrieves the real address contained in the IP packet. Next, the address analysis mechanism 21 collates the address allocation table 31 to check whether the fetched address is an address to be translated.

If the address is registered in the address allocation table 31, the real address is rewritten to the virtual address. Further, when the corresponding address is not registered in the address allocation table 31, the address conversion rule table 32 is referred to. When it is registered here, the address allocation table 3
1 is registered and at the same time the real address is rewritten to the virtual address. The processing up to this point is the same as in the first, second and third embodiments.

Next, when the address conversion is performed by the address analysis mechanism 21, the data pattern extraction unit 36 cuts out the data at the corresponding position from the data portion of the corresponding packet according to the data pattern registration table 35. Next, the data pattern comparison unit 37 compares the cut-out address with the data registered in the data pattern registration table 35, and if they are equal, the address in the packet data recorded at the position registered in the data pattern registration table 35. Is a real address. When the above address is a real address, the in-data address translation mechanism 38 rewrites the real address in the data of the packet into a virtual address.
For example, in the data pattern registration table of FIG.
When the data "06" is recorded in the 15th byte of the packet, it is checked whether the real address is recorded in the 128th byte, and if it is recorded,
Rewrite the real address to a virtual address.

Then, as in the first to third embodiments,
The checksum is recalculated, output processing is performed, and the packet is transmitted. Also, if the corresponding address is not entered in the registration position, without rewriting the address in the data,
The checksum is recalculated, output processing is performed, and the packet is transmitted.

Network B communicating by virtual address
The same applies when the IP packet sent from the router is received by the network interface unit B of the router 1. According to the address assignment table 31 and the address translation rule table 32, the virtual address is converted to a real address if necessary. When the data is rewritten or rewritten, the data pattern comparison unit 37 performs comparison, and if they are equal, the virtual address in the data is rewritten to the real address.

FIG. 17 is a flowchart showing the IP address conversion process. In FIG. 17, when the formal address in the header of the IP packet is rewritten (step S1), the data pattern registration table starts from the data part of the IP packet. The data at the corresponding position is cut out in accordance with 35 (step S2). Then, in step S3, the cut out data is compared with the data of the packet registered in the data pattern registration table 35, and if they match, step S4
At, confirm whether the IP address is entered in the registration position.

When the IP address is entered in the registration position, in step S5, the address in the data is rewritten as in the header of the IP packet, and then in step S6.
In step 1, the checksum is recalculated, output processing is performed as described above, and packet transmission is performed. Also, step S3
If they do not match, or if the IP address is not found in step S4, the checksum is recalculated in step S6, the output processing is performed as described above, and packet transmission is performed.

In this embodiment, as described above, I
Since it is possible to rewrite not only the address in the header of the P packet but also the address included in the data, it is possible to expect avoidance of connection failure even in an application that puts the address in the data for communication.

[0075]

As described above, in the present invention, the address translation table of the router having the address translation function is divided and the address assignment table and the address translation rule table are provided. From the group, the details of address allocation can be determined for each network, and fair and efficient address allocation can be maintained. Moreover, since only the address pair of the machine in communication is registered in the address allocation table, the search time can be shortened and the performance of the machine can be improved.

Further, by making it possible to register the address group in the address conversion rule table, it is not necessary to register all the addresses one-to-one, and the address registration time can be shortened. Does not grow. Furthermore, by providing an in-data address conversion mechanism, a data pattern registration table, a data pattern comparison unit, and a data pattern extraction unit, it is possible to avoid the inability to connect a special application that communicates an address within the data excluding the IP header. In addition, since the router administrator can set the data pattern registration table, it can be expected to support various applications having the above characteristics.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a structure of an IP packet.

FIG. 4 is a diagram showing an example of an address allocation table according to the embodiment of the present invention.

FIG. 5 is a diagram showing an example of an address conversion rule table according to the embodiment of the present invention.

FIG. 6 is a flowchart showing an address rewriting process of the first embodiment.

FIG. 7 is a flowchart showing a search process of an address conversion rule table.

FIG. 8 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 9 is a diagram for explaining address conversion in the second embodiment of the present invention.

FIG. 10 is a flowchart showing the process of the second embodiment.

FIG. 11 is a flowchart (continuation) showing processing of the second embodiment.

FIG. 12 is a diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 13 is a diagram showing an example of an address conversion rule table in the third embodiment.

FIG. 14 is a flowchart showing processing in an address determination unit of the third embodiment.

FIG. 15 is a diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 16 is a diagram showing an example of a data pattern registration table of the present embodiment.

FIG. 17 is a flowchart showing an IP address conversion process in data.

[Explanation of symbols]

 1 router 11, 12 network interface unit 13 routing unit 21 address analysis mechanism 22 address generation mechanism 23 address conversion registration mechanism 31 address allocation table 32 address conversion rule table 33 group address registration mechanism 34 address determination unit 35 data pattern registration table 36 data pattern Extraction unit 37 Data pattern comparison unit 38 In-data address conversion mechanism 39 Address conversion timing unit

Claims (4)

[Claims] 1. An address conversion table for registering a pair of an unofficial address and an official address, and an address taken out from a transmitted packet, with reference to the address conversion table, an unofficial address becomes an official address,
Also, in a router having an address translation function that has an address analysis mechanism (21) that translates an official address into an unofficial address, the address translation table is used to register the correspondence relationship between the unofficial address and the official address ( 32) and an address assignment table that stores the pair of unofficial address and official address of the machine that is actually communicating (31)
And that the address analysis mechanism (21) translates the address extracted from the packet transmitted based on the address pair registered in the address assignment table (31) and the address translation rule table (32). A router with a characteristic address translation function. 2. A router having an address conversion function according to claim 1, further comprising an address conversion timing unit (39) for judging a timing of converting a packet address. 3. A group address registering means (33) for registering an address group of a machine or a network, and an address judging section (34) for judging whether an address in a passing packet corresponds to a group address. A router having the address translation mechanism according to claim 1 or 2, which is provided. 4. A data pattern registration table (35) for registering the data position in the data part or the header part of the received packet, the data pattern, and the position in the packet of the address to be converted when matching the pattern. , A data pattern extraction unit (36) that cuts out data from the received packet based on the position information of the data pattern registered in the data pattern registration table (35), and a pattern registered in the data pattern registration table (35). When the comparison result in the data pattern comparison unit (37) and the data pattern comparison unit (37) that compares the data cut out from the actual packet by the data pattern extraction unit (36) are the same, the data pattern registration table (35) 2. An in-data address conversion mechanism (38) for rewriting the contents of an address position registered in the device according to claim 1, 2 or claim Item 3
Router with the address translation mechanism of.