JP4251044B2 - Session relay device and session relay method - Google Patents

Description

  The present invention relates to a session relay apparatus that relays data between sessions, particularly TCP (Transmission Control Protocol) sessions.

  Generally, a communication application establishes a communication session between transmission / reception terminals and performs communication on the established session. However, when the propagation delay time between the transmitting and receiving terminals is very long, or when communication is performed across networks having different characteristics such as wired and wireless, the throughput of communication between the transmitting and receiving terminals decreases.

  In order to solve this problem, instead of performing communication between the transmitting and receiving terminals in one session, a relay device is installed between the transmitting and receiving terminals, and a session from the transmitting terminal to the relay device and a session from the relay device to the receiving terminal are There is a method for performing communication by relaying data between two sessions. An example of such a relay method is Indirect TCP “Literature Ajay Bakre and BR Badrinath,“ I-TCP; Indirect TCP for Mobile Host ”, Department of Computer Science Rutgers University, DSC-TR-314, 1994; (http: (available from //www.it.iitb.ac.in/it644/papers/i-tcp.pdf) (Non-patent document 1), JP-A-11-252179 (patent document 1), JP-A-2002 There is a system disclosed in Japanese Patent No. 281104 (Patent Document 2).

  The most serious problem when relaying sessions is that TCP session processing generally has a high processing load, and high-speed relay processing is difficult.

  In order to relay a session of a protocol higher than the fourth layer, such as TCP, logically, a transmission process is performed immediately after performing a reception process of a protocol higher than TCP, but the actual operation is as follows. It is as follows.

  After data input from the network is once stored in the memory managed by the operating system privilegedly, the TCP / IP reception process is performed, and the data is temporarily copied to the memory managed by the user application, that is, the session relay unit. Passed. Thereafter, in order to transmit this data, the data is copied again from the memory managed by the session relay unit to the memory managed privileged by the operating system, and after the TCP / IP transmission processing, the operating system manages privilegedly. Data is extracted from the memory space to be output to the network.

  That is, data copy is performed twice in total between the TCP / IP reception process, the session relay unit process, and the TCP / IP transmission process, and this copy process is a heavy load.

  The operation described above will be described in detail with reference to FIG.

  FIG. 21 is a block diagram showing a configuration example of a conventional session relay apparatus. This session relay apparatus receives packet data from a network and stores it in a received packet storage section 13-2. The packet data received from the network is stored in the received packet storage unit 13-2, and the packet data stored in the received packet storage unit 13-2 is subjected to IP and TCP reception processing to the storage unit 13-4. The reception protocol processing unit 13-3 for copying the packet data and the reception protocol processing unit 13-3 copy the packet data and store the packet, the transmission protocol processing unit 13-6 extracts the packet data, and the session relay unit references The operable storage unit 13-4 and the data stored in the storage unit 13-4 are transmitted A session relay unit 13-5 instructing transmission to the processing unit, and the packet data stored in the storage unit 13-4 based on an instruction from the session relay unit 13-5 are copied to the transmission data storage unit 13-7; TCP and IP transmission processing is performed, and the transmission protocol processing unit 13-6 instructs the network output unit 13-8 to output packet data. The transmission protocol processing unit 13-6 copies the data from the storage unit 13-4. A transmission packet storage unit 13-7 for storing packet data, and a network output unit 13-8 for outputting the packet data stored in the transmission packet storage unit 13-7 to the network in accordance with instructions from the transmission protocol output unit 13-6 It is prepared for.

  When packet data arrives from the network, the network input unit 13-1 stores the received packet data in the received packet storage unit 13-2 and notifies the reception protocol processing unit 13-3 of the arrival of the packet. The reception protocol processing unit 13-3 refers to the packet stored in the reception packet storage unit 13-2 and performs IP and TCP reception processing including calculation of a checksum value.

  When the IP and TCP reception processing is completed, the reception protocol processing unit 13-3 copies the packet data to the storage unit 13-4, which is a memory space that can be referenced and operated by the session relay unit 13-5, and the copying is completed. Then, the packet data is erased from the received packet storage unit 13-2. Since the received packet storage unit 13-2 is a memory space that is managed by the operating system in a privileged manner, the session relay unit 13-5 cannot refer to the received packet storage unit 13-2 and thus needs to copy the packet data. .

  The session relay processing unit 13-5 instructs the transmission protocol processing unit 13-6 to transmit the packet data stored in the storage unit 13-4 using TCP / IP. Upon receiving the instruction, the transmission protocol processing unit 13-6 copies the packet data from the storage unit 13-4 to the transmission packet storage unit 13-7, performs TCP and IP processing including checksum calculation, and outputs the data to the network. The unit 13-8 is instructed to send packet data. The network output unit 13-8 reads the packet data from the transmission packet storage unit 13-7 and outputs it to the network.

  As described above, the received packet storage unit 13-2 to the storage unit 13-4, and the storage unit 13-4, between the IP and TCP reception processing, the session relay unit 13-5 processing, and the TCP and IP transmission processing, respectively. The packet data is copied from the packet to the transmission packet storage unit 13-7, and this two copy processing is a heavy load.

  The following methods exist as conventional methods for increasing the speed of TCP session relay processing.

  The first method uses the zero copy TCP method (http://www.freebsd.org/cgi/man.cgi?query=zero_copy & section = 9 & manpath = FreeBSD + 5.0-RELEASE: available from Non-Patent Document 2) Thus, the number of times of data copy is reduced and the processing load of data copy is reduced.

  In this method, virtual movement of data by page mapping is used, and packet data received from the network is directly stored in a memory space managed by the user application, that is, the session relay unit. Similarly, virtual data movement by page mapping is used to directly send memory data managed by the session relay unit to the network. However, since the memory space used at this time is a special memory space negotiated between the session relay unit and the operating system, the data received by the session relay unit from the network cannot be sent as it is. Copies data once in the memory space managed by the session relay unit and moves it to the memory space negotiated with the operating system.

  The operation by the zero copy TCP method will be described with reference to FIG.

  FIG. 22 is a block diagram showing another configuration example of the conventional session relay device. This session relay device receives a packet from the network and stores it in the received packet storage unit 14-2. And a reception protocol processing unit 14-2 that performs IP and TCP reception processing based on the packet header passed from the network input unit, and a memory space negotiated by the session relay unit and the reception protocol processing unit. Received data storage unit 14-3 in which received packet data is stored, and memory space in which packet data stored in received data storage unit 14-3, which is a memory space negotiated with the reception protocol processing unit, is negotiated with the transmission protocol processing unit The data is copied to the transmission data storage unit 14-5 and the data is transmitted to the transmission protocol processing unit Session relay unit 14-4 to instruct, transmission data storage unit 14-5 that is a memory space negotiated with the session relay unit and stores packets to be transmitted to the network, and TCP and IP transmission based on instructions from the session relay unit Process, adds a packet header to the packet data in the transmission data storage unit, and receives instructions from the transmission protocol processing unit 14-6 and the transmission protocol processing unit 14-6 to instruct the network output unit to transmit the packet. A network output unit 14-7 that extracts a packet from the transmission data storage unit 14-4 and transmits the packet to the network is configured.

  When packet data arrives from the network, the network input unit 14-1 passes the header portion of the packet to the reception protocol processing unit 14-2. The reception protocol processing unit 14-2 refers to the packet header portion of the received packet data, performs IP and TCP reception processing, and when the IP and TCP reception processing ends, the reception protocol processing unit 14-3 The network input unit 14-1 is instructed to store the packet data in the received data storage unit 14-3, which is a memory space determined through negotiation with the relay unit 14-4.

  The network input unit 14-1 stores the packet data in the reception data storage unit 14-3 based on an instruction from the reception protocol processing unit 14-2. The reception protocol processing unit 14-2 gives the session relay unit 14-4 the authority to manage the packet data stored in the reception data storage unit 14-3 by page mapping.

  The session relay unit 14-4 copies the packet data to the transmission data storage unit 14-5, which is a memory space negotiated and determined with the transmission protocol processing unit 14-6, and transmits the packet data to the transmission protocol processing unit 14-6. The packet data stored in 14-5 is instructed to be transmitted using TCP / IP.

  The transmission protocol processing unit 14-5 performs TCP and IP transmission processing, adds a packet header to the packet data stored in the transmission data storage unit 14-5, and then transmits the packet data to the network output unit. 5 is instructed to output the packet stored. The network output unit 14-7 reads the packet from the transmission data storage unit 14-5 and outputs it to the network.

  As described above, when receiving data, the packet data arriving at the network input unit 14-1 is directly stored in the memory space negotiated by the reception protocol processing unit 14-2 and the session relay unit 14-4, and the session data is received. The relay unit 14-4 copies the data to the memory space negotiated by the session relay unit 14-4 and the transmission protocol processing unit 14-6, and transmits the data to the session relay unit 14-4 and the transmission protocol. The network output unit 14-7 directly reads out the packet data from the memory space negotiated by the processing unit 14-6. As a result, in the method shown in FIG. 22, the data copy required twice in the method shown in FIG. 21 can be reduced to one time.

The second method is a method for realizing session relay by simplifying or omitting TCP processing in a session relay device. For example, in the method disclosed in Japanese Patent Application Laid-Open No. 2003-179626 (Patent Document 3), the session relay device communicates by TCP / IP in a session with one terminal, and monitors a retransmission packet from this one terminal. Until the number of times the retransmission packet arrives reaches a predetermined number, the other session transmits the retransmission packet as it is. Further, for example, in the method disclosed in Japanese Patent Application Laid-Open No. 2000-122939 (Patent Document 4), the session relay apparatus performs only TCP / IP header conversion and omits TCP processing in both reception and transmission. To do.
Japanese Patent Laid-Open No. 11-252179 JP 2002-281104 A JP 2003-179626 A JP 2000-122939 A Indirect TCP “Literature Ajay Bakre and BRBadrinath,“ I-TCP; Indirect TCP for Mobile Host ”, Department of Computer Science Rutgers University, DSC-TR-314, 1994; (http://www.it.iitb.ac.in (Available from /it644/papers/i-tcp.pdf) Zero copy TCP method (http://www.freebsd.org/cgi/man.cgi?query=zero_copy & section = 9 & manpath = FreeBSD + 5.0-RELEASE) Literature TCP / IP Illustrated, Volume 1: The Protocols, Addison-Wesley, 1994, ISBN 0-201-63346-989

  The first problem is that in the above-described first method, data copy processing in the memory space managed by the session relay unit is required several times. In order to realize high-speed relay processing with a large load due to this copy processing. This is a bottleneck.

  In the zero copy method, which reduces the number of data copies and reduces the processing load of data copy, a special memory space negotiated by the session relay unit and the operating system is used, and a memory space for reception and a memory for transmission are used. Since each space is required, the data received from the network by the session relay unit cannot be transmitted as it is. When transmitting, the data is temporarily copied in the memory space managed by the session relay unit, and the operating system Move to the memory space you negotiated with. Therefore, even with this method, the load due to the copy processing increases.

  The second problem is that the packet length is limited in the first method. In order to use virtual data movement by page mapping, the page size processed by the CPU needs to match the packet length. In general, since the session relay device exists independently of the transmission / reception terminal and the packet length used by the transmission / reception terminal cannot be assumed in advance, the session relay device is used as a transmission / reception terminal using a packet length different from the page size of the bandwidth control device. On the other hand, the processing load cannot be reduced by zero copy.

  The third problem is that in the first method, since the reception processing and transmission processing of the existing TCP / IP protocol are performed as they are, the session relay processing performs sufficient processing twice in one time. The processing cost is high. In particular, in TCP, the checksum calculation is performed on the entire packet data, so that the processing load due to the checksum calculation increases.

  The fourth problem is that in the first method, the processing of the IP layer is performed on all packets, and therefore the processing load of the IP layer is high.

  The fifth problem is that the second method cannot exhibit high throughput when the packet discard rate is high in a network used by a session whose operation is simplified by the session relay apparatus. .

  The present invention has been devised in view of the above problems, and an object thereof is to realize a session relay apparatus that performs relay processing between sessions at high speed.

  In order to solve the first problem, the session relay apparatus according to the present invention does not copy data to the session relay unit, and therefore does not need to use an address designated by the OS at the time of transmission. In other words, the received packet is stored in the reception buffer, and is not stored in the TCP layer, other upper layers, and the application reception buffer, but is stored in the TCP layer, other upper layers, and the application transmission buffer. The process is performed without any problem. Therefore, there is no movement of data in the session relay unit.

  In order to solve the second problem, the session relay apparatus according to the present invention does not copy the data to the session relay unit, and therefore there is no need to move data by page mapping. In other words, the received packet is stored in the reception buffer, and is not stored in the TCP layer, other upper layers, and the application reception buffer, but is stored in the TCP layer, other upper layers, and the application transmission buffer. The process is performed without any problem. Therefore, no data movement in the session relay device occurs, and there is no need for data movement by page mapping.

  In order to solve the third problem, the session relay apparatus according to the present invention calculates the checksum value of the entire packet at the time of reception, and at the time of transmission, the checksum for the part updated in the session relay process as a target. By calculating the value, there is no need to recalculate the checksum for the entire packet.

  In order to solve the fourth problem, in the session relay device according to the present invention, in the session relay processing, only necessary processing is performed for all packets in the IP processing, and packets are transmitted without using the IP layer. By sending out, it is not necessary to carry out all transmission processes of the IP layer for all packets.

  In order to solve the fifth problem, the session relay apparatus according to the present invention realizes a complete TCP operation in the session relay process, so that even if the packet discard rate of the network is high, the TCP packet retransmission operation Is realized and there is little decrease in throughput.

  The first effect of the present invention is that data transfer between buffers can be eliminated and session relay processing can be speeded up by aggregating a plurality of layers of reception buffers and transmission buffers into an IP layer reception buffer. .

  The second effect of the present invention is that the checksum value calculation cost is reduced by reducing the number of checksum value calculations in the reception process and the transmission process to the minimum necessary, and the session relay process is speeded up. It can be done.

  The third effect of the present invention is that it has means for determining whether processing in IP layer transmission processing is necessary and means for omitting this, thereby reducing IP layer transmission processing cost and speeding up session relay processing. Can be realized.

  The fourth effect of the present invention is that in the IP layer transmission processing, processing required for all packets is classified into processing that is not, and in many cases only the former is processed by classifying the former processing. The transmission processing cost can be reduced, and the session relay processing can be speeded up.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a first embodiment of a session relay apparatus according to the present invention.

  The session relay apparatus 1-0 according to the present embodiment receives a packet from the network, performs a TCP / IP reception process, and stores the packet in the storage unit 1-2. The TCP / IP transmission process is performed on the packet stored in the unit 1-2 and the storage unit 1-2 and the reception process in the network input processing unit 1-1 is completed. The packet is taken out from the storage unit 1-2 to the network. The network output processing unit 1-3 outputs a packet.

  In the first embodiment, when data is transmitted from the transmission terminal 10 to the reception terminal 20 as shown in FIG. 2, it is assumed that the session relay device 1-0 realizes data relay. Processing will be described.

  FIG. 2 is a block diagram illustrating a data flow between the session relay device 1-0, the transmission terminal 10, and the reception terminal 20 in the present embodiment.

  When transmitting packet data from the transmission terminal 10 to the reception terminal 20, the transmission terminal 10 transmits a packet storing data to the session relay apparatus 1-0. The session relay terminal 1-0 receives the packet from the transmission terminal 10, and the session relay apparatus 1-0 performs data reception processing. As a result, the session relay apparatus 1-0 transmits the packet received from the transmission terminal 10 to the reception terminal 20.

  Regarding the processing of TCP and IP, RFC 793, RFC 791, RFC 2460 and documents TCP / IP Illustrated, Volume 1: The Protocols, Addison-Wesley, 1994, ISBN 0-201-63346-989 (Non-Patent Document 3). It is described in detail. There are many examples such as TCP / IP protocol stacks such as Linux and Windows (R) as examples of realizing the specifications of these documents. For this reason, in the present embodiment, the contents of the TCP process and the IP process are not essential, and the description thereof is omitted.

  Next, processing performed by the session relay apparatus 1-0 according to the first embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing an outline of processing of the session relay apparatus according to the first embodiment.

  The session relay device 1-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 1-1.

  In step 3-1, the network input processing unit 1-1 stores the packet in the storage unit 1-2.

  In step 3-2, the network input processing unit 1-1 performs an IP reception process.

  In step 3-3, if the IP reception process is normally completed, the process proceeds to the next step. If not, the process is terminated.

  In step 3-4, the network input processing unit 1-1 refers to the packet stored in the storage unit 1-2, and performs a reception process according to the TCP rules on the packet.

  In step 3-5, if the TCP reception process is normally completed, the network output processing unit 1-3 is notified of the storage location of the packet, and the process proceeds to step 3-6. Otherwise, the process is terminated.

  In step 3-6, the network output processing unit 1-3 refers to the packet notified from the network input processing unit 1-1 and stored in the storage unit 1-2, and transmits TCP and IP to the packet. Perform the process. Here, when it is necessary to update the packet header in the TCP and IP transmission processing, the packet header stored in the storage unit 1-2 is overwritten and updated.

  If it is determined in step 3-7 that the packet can be transmitted as a result of the transmission process of TCP and IP, the process proceeds to step 3-5. If not, the process ends.

  In step 3-8, the network output processing unit 1-3 extracts the packet from the storage unit 1-2 and transmits the packet to the receiving terminal 20.

  In step 3-9, the network output processing unit 1-3 sends the packet to the receiving terminal 20, and if the receiving terminal 20 confirms that the packet has been normally received, the network output processing unit 1-3 stores the packet. Delete from 1-2.

  The above is the content of the session relay processing in the session relay device 1-0 according to the first embodiment.

  In the conventional technique, after the network input unit performs reception processing, when passing data to the network output unit, the packet is copied in the storage unit, and the network output unit is copied to the copied packet. Since the transmission processing is performed, packet copy overhead occurs, which causes performance degradation.

  On the other hand, as described above, in this embodiment, the data packet to be relayed is stored in the storage unit 1-2 at the time of reception of the network input processing unit 1-1, and this is transmitted by the network output processing unit 1-3 at the time of transmission. Since reception and transmission processing are performed on the same packet without performing any copying until it is taken out from the storage unit 1-2, overhead due to the copy processing can be reduced.

  FIG. 4 is a block diagram showing the configuration of the session relay device according to the second embodiment of the present invention. The session relay device 4-0 according to the second embodiment includes a network input unit 4-1 that receives a packet from the network and stores it in the storage unit 4-2, a storage unit 4-2 that stores the arrived packet, and a storage. The reception protocol processing unit 4-3 that performs reception processing of IP and TCP on the packet stored in the unit 4-2, and instructs the transmission protocol processing unit 4-4 to process the packet, and the storage unit 4-2 The transmission protocol processing unit 4-4, the transmission protocol processing unit 4-3, and the reception protocol processing unit that perform TCP and IP transmission processing on the packets that are stored in the packet and for which the reception processing by the reception protocol processing unit 4-3 has been completed The network output unit 4-5 is configured to take out the packet from the storage unit 4-2 based on the instruction 4-4 and output the packet to the network.

  In the second embodiment, it is assumed that the session relay device 4-0 realizes data relay when data is transmitted from the transmission terminal 10 to the reception terminal 20, as shown in FIG. explain.

  FIG. 5 is a block diagram illustrating a data flow between the session relay device, the transmission terminal, and the reception terminal in the present embodiment. When transmitting data from the transmission terminal 10 to the reception terminal 20, the transmission terminal 10 transmits a packet storing data to the session relay device 4-0. The session relay terminal 4-0 receives the packet from the transmission terminal 10, and the session relay apparatus 4-0 performs data reception processing. Thereby, the session relay device 4-0 transmits the packet received from the transmission terminal 10 to the reception terminal 20.

  In the present embodiment, the contents of the TCP and IP processes themselves are not essential, and thus the description thereof is omitted.

  Next, processing by the session relay device 4-0 according to the second embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing an outline of processing of the session relay apparatus according to the second embodiment.

  The session relay device 4-0 starts processing when a packet from the transmission terminal 10 arrives at the network input unit 4-1.

  In step 6-1, the network input unit 4-1 stores the packet in the storage unit 4-2. The network input unit 4-1 notifies the reception protocol processing unit 4-3 that the packet has been stored.

  In step 6-2, the reception protocol processing unit 4-4 performs IP reception processing.

  In step 6-3, when the IP reception process is normally completed, the process proceeds to step 6-4. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 6-4, the reception protocol processing unit 4-3 refers to the packet stored in the storage unit 4-2, and performs a reception process according to the TCP rules on the packet.

  In step 6-5, when the TCP reception process is normally completed, the storage location of the packet is notified to the transmission protocol processing unit 4-4, and the process proceeds to step 6-6. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 6-6, the transmission protocol processing unit 4-4 refers to the packet notified from the reception protocol processing unit 4-3 and stored in the storage unit 4-2, and transmits TCP and IP to the packet. Perform the process. When it is necessary to update the packet header in the TCP and IP transmission processing, the packet header stored in the storage unit 4-2 is overwritten and updated.

  If it is determined in step 6-7 that the packet can be transmitted as a result of the TCP and IP transmission processing, the process proceeds to step 6-8. If not, the process ends.

  In step 6-8, the transmission protocol processing unit 4-4 notifies the network output unit 4-5 of the location where the packet is stored, and instructs to output the packet.

  In step 6-9, the network output unit 4-5 extracts the packet from the storage unit 4-2 based on the instruction, and transmits the packet to the receiving terminal 20.

  In step 6-10, when the network output unit 4-5 confirms that the packet transmitted to the receiving terminal 20 has been normally received by the receiving terminal 20, the network output unit 4-5 deletes the packet. -4. In response to this, the transmission protocol processing unit 4-4 deletes the packet.

  The above is the content of the session relay processing in the session relay device 4-0 according to the second embodiment.

  In the conventional technique, after the reception processing unit performs reception processing, the packet is copied to the transmission processing unit in the storage unit, and the transmission processing unit performs transmission processing on the copied packet. Copy overhead has occurred, which causes performance degradation.

  On the other hand, as described above, in this embodiment, the data packet to be relayed is stored in the storage unit 4-2 at the time of reception of the network input unit 4-1, and this is transmitted from the storage unit 4-2 at the time of transmission. Since reception and transmission processing are performed for the same packet without performing any copying until extraction, overhead due to copying can be reduced.

  Since the configuration of the session relay apparatus according to the third embodiment of the present invention is the same as that of the first embodiment shown in FIG. 1, here, FIGS. 1 and 2 showing the configuration of the first embodiment are used. explain. Only the differences from the first embodiment will be described below.

  In the session relay apparatus of the third embodiment, the network input processing unit 1-1 calculates the TCP and IP checksum values that have arrived, and the TCP checksum value and IP checksum stored in the packet. If the value does not match the calculation result, the packet is discarded, and if the checksum value stored in the packet matches the calculation result, it is stored in the storage unit 1-2.

  The network output processing unit 1-3 calculates the difference of the checksum value only for the updated part of the packet only when the packet is updated, and reflects the calculated difference in the checksum value stored in the packet Update to Alternatively, the network output processing unit 1-3 is configured to calculate the checksum value of the entire header portion of the packet and to obtain the difference in order to simplify the determination of the portion for calculating the difference between the checksum values. Is also possible.

  Next, processing by the session relay device according to the third embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing an outline of processing of the session relay device according to the third embodiment.

  The session relay device 1-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 1-1.

  In step 7-1, the network input processing unit 1-1 calculates TCP and IP checksum values for the packet.

  In step 7-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 7-3.

  In step 7-3, the network input processing unit 1-1 stores the packet in the storage unit 1-2.

  In step 7-4, the network input processing unit 1-1 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 7-5, when the IP reception process is normally completed, the process proceeds to step 7-6. Otherwise, the packet is deleted from the storage unit and the process is terminated.

  In step 7-6, the network input processing unit 1-1 refers to the packet stored in the storage unit 1-2, and performs a reception process according to the TCP rules on the packet.

  In step 7-7, if the TCP reception process is normally completed, the storage position of the packet is notified to the network output processing unit 1-3, and the process proceeds to the next step. Otherwise, the process is terminated.

  In step 7-8, the network output processing unit 1-3 refers to the packet notified from the network input processing unit 1-1 and stored in the storage unit 1-2, and transmits TCP and IP to the packet. Perform the process. When it is necessary to update the packet header in the TCP and IP transmission processing, the packet header stored in the storage unit 1-2 is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  If it is determined in step 7-9 that transmission of the packet is possible as a result of the transmission processing of TCP and IP, the process proceeds to step 7-10. If not, the process ends.

  In Step 7-10, the network output processing unit 1-3 extracts the packet from the storage unit 1-2 and transmits it to the receiving terminal 20.

  In step 7-11, when the network output processing unit 1-3 confirms that the receiving terminal 20 has normally received the transmitted packet, the network output processing unit 1-3 deletes the packet from the storage unit 1-2.

  The above is the content of the session relay processing in the session relay device according to the third embodiment.

  As described above, in this embodiment, by checking the checksum for the entire packet in the network input processing unit 1-2, it is possible to reduce the trouble of calculating the checksum value in the transmission protocol processing unit. The calculation processing load can be reduced.

  Since the configuration of the session relay apparatus according to the fourth embodiment of the present invention is the same as that of the second embodiment shown in FIG. 4, the block diagrams 4 and 5 showing the configuration of the second embodiment are used here. I will explain. Only the differences from the second embodiment will be described below.

  Here, the checksum calculation included in the TCP and IP reception processing and transmission processing of the second embodiment will be described.

  The network input unit 4-1 calculates the TCP and IP checksum values that have arrived, and the TCP checksum value stored in the packet. If the IP checksum value and the calculation result do not match, the network input unit 4-1 When the checksum value stored in the packet matches the calculation result, it is stored in the storage unit 4-2.

  The reception protocol processing unit 4-3 omits the checksum calculation included in the TCP protocol and the IP protocol, and the transmission protocol processing unit 4-4 checks only the updated part of the packet only when the packet is updated. The value difference is calculated and updated so that the calculated difference is reflected in the checksum value stored in the packet. Alternatively, the transmission protocol processing unit 4-4 is configured to calculate the checksum value of the entire header portion of the packet and to obtain the difference in order to simplify the determination of the portion for calculating the difference between the checksum values. It is also possible.

  Next, processing by the session relay device according to the fourth embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing an outline of processing of the session relay device according to the fourth embodiment.

  The session relay device starts processing when a packet from the transmission terminal 10 arrives at the network input unit 4-1.

  In step 8-1, the network input unit 4-1 calculates TCP and IP checksum values for the packet.

  In step 8-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 8-3.

  In Step 8-3, the network input unit 4-1 stores the packet in the storage unit 4-2. The network input unit 4-1 notifies the reception protocol processing unit 4-3 that the packet has been stored.

  In Step 8-4, the reception protocol processing unit 4-4 performs IP reception processing. However, the IP checksum value is not confirmed.

  In step 8-5, when the IP reception process is normally completed, the process proceeds to step 8-6. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In Step 8-6, the reception protocol processing unit 4-3 refers to the packet stored in the storage unit 4-2, and performs a reception process according to the TCP rules on the packet.

  In step 8-7, when the TCP reception process is normally completed, the transmission protocol processing unit 4-4 is notified of the storage location of the packet, and the process proceeds to step 8-8. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 8-8, the transmission protocol processing unit 4-4 refers to the packet notified from the reception protocol processing unit 4-3 and stored in the storage unit 4-2, and transmits TCP and IP to the packet. Perform the process. When it is necessary to update the packet header in TCP and IP transmission processing, the packet header stored in the storage unit is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  If it is determined in step 8-9 that the transmission of the packet is possible as a result of the TCP and IP transmission processing, the process proceeds to step 8-10. If not, the process ends.

  In step 8-10, the transmission protocol processing unit 4-4 notifies the network output unit 4-5 of the location where the packet is stored, and instructs to output the packet.

  In step 8-11, the network output unit 4-5 extracts the packet from the storage unit 4-2 based on the instruction and transmits it to the receiving terminal 20.

  In step 8-12, when the network output unit 4-5 confirms that the received terminal 20 has received the transmitted packet normally, the network output unit 4-5 requests the transmission protocol processing unit 4-4 to delete the packet. In response to this, the transmission protocol processing unit 4-4 deletes the packet.

  The above is the content of the session relay processing in the session relay device according to the fourth embodiment.

  As described above, in this embodiment, the checksum calculation in the reception protocol processing unit 4-3 can be omitted by checking the checksum for the entire packet by the network input unit 4-1, and the transmission protocol processing unit 4- 4 can be reduced, and the processing load for calculating the checksum value can be reduced.

  In particular, an embodiment in which the session relay device is realized by using a general-purpose computer and the network input unit 4-1 is a network interface card having a checksum calculation function is also possible. Since the calculation of the checksum calculated by the CPU is greatly reduced, the effect is high.

  Since the configuration of the session relay apparatus according to the fifth embodiment of the present invention is the same as that of the first embodiment shown in FIG. 1, here, FIGS. 1 and 2 showing the configuration of the first embodiment are used. explain. Only the differences from the third embodiment will be described below.

  In the session relay device according to the fifth embodiment, the network output processing unit 1-3 performs the IP transmission processing of the transmission processing based on the communication setting and the communication state between the session relay device and the receiving terminal 20. It has a function to decide whether to omit or omit.

  The network output processing unit 1-3 performs the IP transmission process when it is determined that the IP transmission process is necessary, and omits the IP transmission process when it is determined that the IP transmission process can be omitted. It has a function of outputting packets to the network.

  The situation in which the network output processing unit 1-3 determines that IP transmission processing is necessary is when a technique for converting an IP address such as NAT or IP masquerade is set in the IP processing of the network output processing unit 1-3. This is a case where parameters such as ARP and ICMP which are set as a result and used to output a packet to the network are not held.

  Also, when the parameters used to output packets to the network are changed by ICMP redirect or spanning tree, it is necessary to acquire the parameters again by IP layer processing, so IP transmission processing is required It corresponds to. The checksum calculation is a process necessary for all IP transmission processes, but is omitted in the IP transmission process according to the third embodiment of the present invention, and is not a target here.

  Here, in order to simplify the procedure for determining whether IP transmission processing is necessary or not, the network output processing unit 1-3 includes the transmission terminal 10, the session relay device 1-0, and the session relay device 1-. For packets used when a session between 0 and the receiving terminal 20 is established, there is a high possibility that ARP, ICMP, or the like is used. After the process is performed and a session is established and some packets are exchanged with the receiving terminal 20, the IP layer process is omitted.

  However, the network output processing unit 1-3 determines that IP layer processing is necessary when NAT and IP masquerading are set to IP processing of transmission protocol processing, and always performs IP layer transmission processing. When the destination of the lower layer is changed by ICMP redirect or spanning tree, transmission processing of the IP layer is performed.

  Next, processing by the session relay device according to the fifth embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing an outline of processing of the session relay apparatus according to the fifth embodiment.

  The session relay device 1-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 1-1.

  In step 9-1, the network input processing unit 1-1 calculates TCP and IP checksum values for the packet.

  In step 9-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 9-3.

  In step 9-3, the network input processing unit 1-1 stores the packet in the storage unit 1-2.

  In step 9-4, the network input processing unit 1-1 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 9-5, when the IP reception process is normally completed, the process proceeds to step 9-6. Otherwise, the packet is deleted from the storage unit and the process is terminated.

  In step 9-6, the network input processing unit 1-1 refers to the packet stored in the storage unit 1-2, and performs a reception process according to the TCP rules on the packet.

  In step 9-7, if the TCP reception process is normally completed, the storage position of the packet is notified to the network output processing unit 1-3, and the process proceeds to the next step. Otherwise, the process is terminated.

  In step 9-8, the network output processing unit 1-3 refers to the packet notified from the network input processing unit 1-1 and stored in the storage unit 1-2, and performs TCP transmission processing on the packet. carry out. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 1-2 is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  If it is determined in step 9-9 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 9-10. If not, the process ends.

  In Step 9-10, the network output processing unit 1-3 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 9-11. Otherwise, go to Step 9-12.

  In step 9-11, the network output processing unit 1-3 refers to the packet stored in the storage unit 1-2, and performs IP transmission processing on the packet.

  In Step 9-12, the network output processing unit 1-3 takes out the packet from the storage unit 1-2 and sends the packet to the receiving terminal 20.

  If it is confirmed in step 9-13 that the receiving terminal 20 has received the transmitted packet normally, the packet is deleted from the storage unit 1-2.

  The above is the content of the session relay processing in the session relay device according to the fifth embodiment.

  As described above, in this embodiment, the network output processing unit 1-3 has a function of determining whether or not the IP layer processing can be omitted, and a function of omitting the IP layer processing and outputting a packet to the network. IP layer processing can be reduced.

  Since the configuration of the session relay apparatus according to the sixth embodiment of the present invention is the same as that of the second embodiment, description will be made here with reference to block diagrams 4 and 5 showing the configuration of the second embodiment. Here, only differences from the second embodiment will be described.

  In the session relay device 4-0, the transmission protocol processing unit 4-4 performs IP transmission processing among the transmission processing based on the communication settings and the communication state between the session relay device 4-0 and the receiving terminal 20. It has a function to decide whether to omit or omit.

  If the transmission protocol processing unit 4-4 determines that IP transmission processing is necessary, the transmission protocol processing unit 4-4 performs IP transmission processing. On the other hand, when it is determined that the IP transmission process can be omitted, the IP transmission process is omitted, and the network output unit 4-5 has a function of instructing the packet output.

  The situation where it is determined that the IP transmission process cannot be omitted is based on the case where a technique for converting an IP address such as NAT or IP masquerade is set in the IP process of the transmission protocol processing unit 4-4 and the result of ARP, ICMP, This is a case where a parameter that is set and used to output a packet to the network is not held.

  Further, even when the destination of the lower layer is changed by ICMP redirect or spanning tree, it is necessary to acquire the parameter by the IP layer processing again, and this corresponds to the case where the IP transmission processing cannot be omitted. The checksum calculation is necessary for all IP transmission processes, but is omitted in the IP transmission process according to the fourth embodiment of the present invention, and is not the target here.

  However, the transmission protocol processing unit 4-4 determines that the IP layer processing is necessary when NAT and IP masquerading are set to the IP processing of the transmission protocol processing, and always performs the IP layer transmission processing. When the destination of the lower layer is changed by ICMP redirect or spanning tree, transmission processing of the IP layer is performed.

  Next, processing by the session relay apparatus according to the sixth embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing an outline of processing of the session relay device according to the sixth embodiment.

  The session relay device 4-0 starts processing when a packet from the transmission terminal 10 arrives at the network input unit 4-1.

  In step 10-1, the network input unit 4-1 calculates TCP and IP checksum values for the packet.

  In step 10-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 10-3.

  In step 10-3, the network input unit 4-1 stores the packet in the storage unit 4-2. The network input unit 4-1 notifies the reception protocol processing unit 4-3 that the packet has been stored.

  In Step 10-4, the reception protocol processing unit 4-4 performs IP reception processing. However, the IP checksum value is not confirmed.

  In step 10-5, when the IP reception process is normally completed, the process proceeds to step 10-6. Otherwise, the packet is deleted from the storage unit and the process is terminated.

  In step 10-6, the reception protocol processing unit 4-3 refers to the packet stored in the storage unit 4-2, and performs a reception process according to the TCP rules on the packet.

  In step 10-7, when the TCP reception process is normally completed, the storage location of the packet is notified to the transmission protocol processing unit 4-4, and the process proceeds to step 10-8. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 10-8, the transmission protocol processing unit 4-4 refers to the packet notified from the reception protocol processing unit 4-3 and stored in the storage unit 4-2, and performs TCP transmission processing on the packet. carry out. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 4-2 is overwritten and updated. However, the checksum is updated so that the difference between the TCP and IP checksum values is calculated only for the updated portion of the packet, and the calculated difference is reflected in the checksum value stored in the packet.

  If it is determined in step 10-9 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 10-10. If not, the process ends.

  In step 10-10, the transmission protocol processing unit 4-4 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 10-11. Otherwise, go to Step 10-12.

  In step 10-11, the transmission protocol processing unit 4-4 refers to the packet stored in the storage unit 4-2, and performs IP transmission processing on the packet.

  In step 10-12, the transmission protocol processing unit 4-4 notifies the network output unit 4-5 of the position where the packet is stored, and instructs to output the packet.

  In step 10-13, the network output unit 4-5 extracts the packet from the storage unit 4-2 based on the instruction, and transmits the packet to the receiving terminal 20.

  In step 10-14, when the network output unit 4-5 confirms that the receiving terminal 20 has received the transmitted packet normally, the network output unit 4-5 requests the transmission protocol processing unit 4-4 to delete the packet. In response to this, the transmission protocol processing unit 4-4 deletes the packet.

  The above is the content of the session relay processing in the session relay device according to the sixth embodiment.

  As described above, in this embodiment, the transmission protocol processing unit 4-4 determines whether or not the IP layer processing can be omitted, and the packet output to the network output unit 4-5 without the IP layer processing. By having the function of instructing the IP layer, the IP layer processing can be reduced.

  Since the configuration of the session relay apparatus according to the seventh embodiment of the present invention is the same as that of the first and fifth embodiments, description will be made here with reference to block diagrams 1 and 2 showing the configuration of the fifth embodiment. To do. Here, only differences from the fifth embodiment will be described.

  In the session relay device 1-0 of the seventh embodiment, the network output processing unit 1-3 has a function of executing processing common to all packets in IP layer transmission processing.

  Among the IP layer processing, what is common to all packets is the checksum value calculation described in the third embodiment, and when NAT (network address translation), IP masquerade, etc. are set, this is also the case. Applicable.

  The calculation of the checksum value is a process necessary for all IP transmission processes, but is omitted in the IP layer transmission process according to the third embodiment of the present invention.

  The network output processing unit 1-3 always executes the IP layer process when NAT and IP masquerade are set, and omits the IP layer process when NAT and IP masquerade are not set. The packet is extracted from the storage unit 1-2 and output to the network.

  Next, processing by the session relay device according to the seventh embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing an outline of processing of the session relay device according to the seventh embodiment.

  The session relay device 1-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 1-1.

  In step 11-1, the network input processing unit 1-1 calculates TCP and IP checksum values for the packet.

  In step 11-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 11-3.

  In step 11-3, the network input processing unit 1-1 stores the packet in the storage unit 1-2.

  In step 11-4, the network input processing unit 1-1 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 11-5, when the IP reception process is normally completed, the process proceeds to step 11-6. Otherwise, the packet is deleted from the storage unit and the process is terminated.

  In step 11-6, the network input processing unit 1-1 refers to the packet stored in the storage unit 1-2, and performs a reception process according to the TCP rules on the packet.

  In step 11-7, when the TCP reception process is normally completed, the storage position of the packet is notified to the network output processing unit 1-3, and the process proceeds to the next step 11-8. Otherwise, the process is terminated.

  In step 11-8, the network output processing unit 1-3 refers to the packet notified from the network input processing unit 1-1 and stored in the storage unit 1-2, and performs TCP transmission processing on the packet. carry out. Here, if NAT is set in the IP processing, the NAT processing is performed. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 1-2 is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  If it is determined in step 11-9 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 11-10. If not, the process ends.

  In step 11-10, the network output processing unit 1-3 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 11-11. Otherwise, go to step 11-12.

  In step 11-11, the network output processing unit 1-3 refers to the packet stored in the storage unit 1-2, and performs IP transmission processing on the packet.

  In step 11-12, the network output processing unit 1-3 extracts the packet from the storage unit 1-2 and sends the packet to the receiving terminal 20.

  If it is confirmed in step 11-13 that the receiving terminal 20 has normally received the transmitted packet, the packet is deleted from the storage unit 1-2.

  The above is the content of the session relay processing in the session relay device according to the seventh embodiment.

  As described above, in the present embodiment, only the processing common to all packets among the IP layer transmission processing is performed, and all other processing is performed by omitting the other processing. Probability can be kept low, and IP layer processing can be reduced.

  Since the configuration of the session relay apparatus according to the eighth embodiment of the present invention is the same as that of the second and sixth embodiments, description will be made with reference to block diagrams 4 and 5 showing the configuration of the second embodiment. To do. Here, only differences from the sixth embodiment will be described.

  In the session relay device 4-0 of the eighth embodiment, the transmission protocol processing unit 4-4 has a function of executing processing common to all packets in the IP layer transmission processing.

  Among the IP layer processing, what is common to all packets is the checksum value calculation described in the third embodiment, and when NAT (network address translation), IP masquerade, etc. are set, this is also the case. Applicable.

  The calculation of the checksum value is a process necessary for all IP transmission processes, but is omitted in the IP layer transmission process according to the third embodiment of the present invention.

  If NAT and IP masquerade are set, the transmission protocol processing unit 4-4 always performs this in the IP layer processing. Instructs the unit 4-5 to output the packet.

  Next, processing by the session relay device according to the eighth embodiment will be described with reference to FIG. FIG. 12 is a flowchart showing an outline of processing of the session relay device according to the eighth embodiment.

  The session relay device 4-0 starts processing when a packet from the transmission terminal 10 arrives at the network input unit 4-1.

  In step 12-1, the network input unit 4-1 calculates TCP and IP checksum values for the packet.

  In step 12-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 12-3.

  In step 12-3, the network input unit 4-1 stores the packet in the storage unit 4-2. The network input unit 4-1 notifies the reception protocol processing unit 4-3 that the packet has been stored, and proceeds to step 12-4.

  In Step 12-4, the reception protocol processing unit 4-4 performs IP reception processing. However, the IP checksum value is not confirmed.

  In Step 12-5, when the IP reception process is normally completed, the process proceeds to Step 12-6. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 12-6, the reception protocol processing unit 4-3 refers to the packet stored in the storage unit 4-2, and performs a reception process according to the TCP rules on the packet.

  In step 12-7, when the TCP reception process is normally completed, the storage location of the packet is notified to the transmission protocol processing unit 4-4, and the process proceeds to step 12-8. Otherwise, the packet is deleted from the storage unit 4-2, and the process ends.

  In step 12-8, the transmission protocol processing unit 4-4 refers to the packet notified from the reception protocol processing unit 4-3 and stored in the storage unit 4-2, and performs TCP transmission processing on the packet. carry out. Here, if NAT is set in the IP processing, the NAT processing is performed. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 4-2 is overwritten and updated. However, the checksum is updated so that the difference between the TCP and IP checksum values is calculated only for the updated portion of the packet, and the calculated difference is reflected in the checksum value stored in the packet.

  If it is determined in step 12-9 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 12-10. If not, the process ends.

  In step 12-10, the transmission protocol processing unit 4-4 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 12-11. Otherwise, go to Step 12-12.

  In Step 12-11, the transmission protocol processing unit 4-4 refers to the packet stored in the storage unit 4-2, and performs IP transmission processing on the packet.

  In step 12-12, the transmission protocol processing unit 4-4 notifies the network output unit 4-5 of the position where the packet is stored, and instructs to output the packet.

  In step 12-13, the network output unit 4-5 extracts the packet from the storage unit 4-2 based on the instruction, and transmits the packet to the receiving terminal 20.

  In step 12-14, when the network output unit 4-5 confirms that the transmitted packet is normally received by the receiving terminal 20, the network output unit 4-5 requests the transmission protocol processing unit 4-4 to delete the packet. In response to this, the transmission protocol processing unit 4-4 deletes the packet.

  The above is the content of the session relay processing in the session relay device according to the eighth embodiment.

  As described above, in the present embodiment, only the processing common to all packets among the IP layer transmission processing is performed, and all other processing is performed by omitting the other processing. Probability can be kept low, and IP layer processing can be reduced.

  FIG. 13 is a block diagram showing the configuration of the session relay device according to the ninth embodiment of the present invention. In this embodiment, the session relay device 15-0 receives a packet from the network, performs a TCP / IP reception process, and stores the packet at the address of the storage unit 15-2 acquired using the memory management unit. The network input processing unit 15-1 and the storage unit 15-2 managed by the memory management unit 15-4 and stored in the storage unit 15-2, and the reception process in the network input processing unit 15-1 are completed. Memory management for managing the access authority and address of the network output processing unit 15-3, which performs TCP / IP transmission processing on the packet, outputs the packet from the storage unit 15-2, and outputs the packet to the network The unit 15-4 is provided.

  In the session relay apparatus according to the present invention, since the connection between the transmission terminal 10, the session relay apparatus 15-0, and the reception terminal 20 is the same as that in the first embodiment, FIG. 1 showing the first embodiment is used. I will explain. Here, only differences from the first embodiment will be described.

  The session relay device 15-0 of this embodiment operates on a general-purpose computer, and the network input processing unit 15-1 and the network output processing unit 15-3 have memory management authority and processing authority equivalent to those of the operating system. The storage unit 15-2 is accessed using the unit 15-4. The storage unit 15-2 is a memory space that is privilegedly accessed from the operating system and the memory management unit 15-4.

  Next, processing by the session relay device 15-0 according to the ninth embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing an outline of processing of the session relay device according to the ninth embodiment.

  The session relay device 15-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 15-1.

  In step 14-1, the network input processing unit 15-1 calculates a TCP and IP checksum value for the packet.

  In step 14-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 14-3.

  In step 14-3, the network input processing unit 15-1 inquires of the memory management unit 15-4 about available addresses in the storage unit 14-2. As a result, the memory management unit 15-4 notifies the network input processing unit 15-1 of the address of the space available in the storage unit 15-2.

  In Step 14-4, the network input processing unit 14-1 stores the packet at the address notified from the memory management unit 15-4, and proceeds to Step 14-5.

  In Step 14-5, the network input processing unit 15-1 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 14-6, when the IP reception process is normally completed, the process proceeds to step 14-7. If not, the memory management unit 15-4 is instructed to release the space where the packet is stored, and the memory management unit 15-4 deletes the space where the packet is stored in the storage unit 15-2 and performs processing. finish.

  In step 14-7, the network input processing unit 15-1 refers to the packet stored in the storage unit 15-2, and performs a reception process according to the TCP rules on the packet.

  In step 14-8, when the TCP reception processing is normally completed, the storage position of the packet is notified to the network output processing unit 15-3, and the process proceeds to the next step. Otherwise, the process is terminated.

  In step 14-9, the network output processing unit 15-3 refers to the packet notified from the network input processing unit 15-1 and stored in the storage unit 15-2, and performs TCP transmission processing on the packet. carry out. If NAT is set in IP processing, NAT processing is performed. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 15-2 is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  In step 14-10, when it is determined that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 14-11. If not, the process ends.

  In Step 14-11, the network output processing unit 15-3 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 14-12. Otherwise, go to Step 14-13.

  In Step 14-12, the network output processing unit 15-3 refers to the packet stored in the storage unit 15-2, and performs IP transmission processing on the packet.

  In step 14-13, the network output processing unit 15-3 extracts the packet from the storage unit 15-2 and sends the packet to the receiving terminal 20.

  In step 14-14, when the receiving terminal 20 confirms that the packet is normally received, the memory management unit 15-4 is requested to delete the packet from the storage unit 15-2. In response to this, the memory management unit 15-4 releases the space of the storage unit 15-2 in which the packet is stored, and ends the process.

  The above is the content of the session relay processing in the session relay device according to the ninth embodiment.

  As described above, in this embodiment, the network input processing unit 15-1 and the network output processing unit 15-3 use the same memory management unit 15-4, so that the storage unit secured when a packet is input. The memory space of 15-2 is continuously used, and the processing up to reception protocol processing, transmission protocol processing, and packet output to the network is performed. As a result, even when the processing procedure is complicated, it is possible to safely use the same storage unit from each processing unit.

  FIG. 15 is a block diagram showing a configuration of a session relay device according to the tenth embodiment of the present invention. In this embodiment, the session relay device 17-0 has received a packet from the network, and has arrived at the network input unit 17-1, which stores the packet in the space of the storage unit 17-2 obtained using the memory management unit. The storage unit 17-2 in which the packet is stored and the packet stored in the storage unit 17-2 are subjected to reception processing up to the layer that realizes session relay, and the transmission protocol processing unit is instructed to process the packet. Protocol processing unit 17-3, transmission protocol processing unit that performs transmission processing up to a layer that realizes session relay for a packet that is stored in the storage unit 17-2 and that has been received by the reception protocol processing unit 17-3 17-4, from the storage unit 17-2 based on the instructions of the transmission protocol processing unit 17-3 and the reception protocol processing unit 17-4 Network output unit 17-5 outputs to the network takes out the packet, and a memory management unit 17-6 for managing access rights and address of the storage unit 17-2.

  In the session relay device 17-0 of the present embodiment, since the connection between the transmission terminal 10, the session relay device 17-0, and the reception terminal 20 is the same as that of the second embodiment, the second embodiment will be described. This will be described with reference to FIG. Here, only differences from the second embodiment will be described.

  The session relay device 17-0 of this embodiment operates on a general-purpose computer, the network input unit 17-1 and the network output unit 17-5 are network interface cards, and the reception protocol processing unit 17-3 and transmission protocol processing. The unit 17-4 manages the storage unit 17-2 by using the memory management unit 17-6 having the same memory management authority and processing authority as those of the operating system. The storage unit 17-2 is a memory space that is privilegedly accessed from the operating system and the memory management unit.

  Next, processing performed by the session relay device 15-0 according to the tenth embodiment will be described with reference to FIG. FIG. 16 is a flowchart showing an outline of processing of the session relay device according to the tenth embodiment.

  The session relay device 17-0 starts processing when a packet from the transmission terminal 10 arrives at the network input unit 17-1.

  In step 16-1, the network input unit 17-1 calculates TCP and IP checksum values for the packet.

  In Step 16-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 16-3.

  In step 16-3, the network input unit 17-1 inquires of the memory management unit 17-6 about available addresses of the storage unit 17-2. The memory management unit 17-6 notifies the network input unit 17-1 of the address of the space that can be used in the storage unit 17-2.

  In step 16-4, the network input unit 17-1 stores the packet at the address of the storage unit 17-2 notified from the memory management unit 17-6, and transmits the packet to the reception protocol processing unit 17-3. Notify that it has been stored. Then, the process proceeds to step 16-5.

  In Step 16-5, the reception protocol processing unit 17-3 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 16-6, when the IP reception process is normally completed, the process proceeds to step 16-7. Otherwise, the packet is deleted from the storage unit 17-2 and the process ends.

  In Step 16-7, the reception protocol processing unit 17-3 refers to the packet stored in the storage unit 17-2, and performs a reception process according to the TCP rules on the packet.

  In step 16-8, when the TCP reception process is completed normally, the transmission protocol processing unit 17-4 is notified of the storage location of the packet, and the process proceeds to the next step. Otherwise, the packet is deleted from the storage unit 17-2 and the process ends.

  In step 16-9, the transmission protocol processing unit 17-4 refers to the packet notified from the reception protocol processing unit 17-3 and stored in the storage unit 17-2, and performs TCP transmission processing on the packet. carry out. If NAT is set in IP processing, NAT processing is performed. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 17-2 is overwritten and updated. However, the checksum is updated so that the difference between the TCP and IP checksum values is calculated only for the updated portion of the packet, and the calculated difference is reflected in the checksum value stored in the packet.

  If it is determined in step 16-10 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 16-11. If not, the process ends.

  In Step 16-11, the transmission protocol processing unit 17-4 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 16-12. Otherwise, go to Step 16-13.

  In Step 16-12, the transmission protocol processing unit 17-4 refers to the packet stored in the storage unit 17-2 and performs IP transmission processing on the packet.

  In step 16-13, the transmission protocol processing unit 17-4 notifies the network output unit 17-5 of the location where the packet is stored, and instructs to output the packet.

  In Step 16-14, the network output unit 17-5 extracts the packet from the storage unit 17-2 and transmits it to the receiving terminal 20.

  In step 16-15, when the network output unit 17-5 confirms that the packet is normally received by the receiving terminal 20, the network output unit 17-5 requests the transmission protocol processing unit 17-4 to delete the packet. In response to this, the transmission protocol processing unit 17-4 requests the memory management unit 17-6 to delete the packet from the storage unit 17-2. The memory management unit 17-6 releases the space of the storage unit in which the packet is stored, and ends the process.

  The above is the content of the session relay processing in the session relay device according to the tenth embodiment.

  As described above, in this embodiment, the network input unit 17-1, the reception protocol processing unit 17-3, and the transmission protocol processing unit 17-4 use the same memory management unit 17-6, so that packets are transmitted. The memory space of the storage unit 17-2 secured at the time of input is continuously used, and the processes up to reception protocol processing, transmission protocol processing, and packet output to the network are performed. As a result, even when the processing procedure is complicated, it is possible to safely use the same storage unit from each processing unit.

  FIG. 17 is a block diagram showing the configuration of the session relay device according to the eleventh embodiment of the present invention. In this embodiment, the session relay device 19-0 receives a packet from the network, determines a session to which the packet belongs, determines whether to perform session relay, performs a TCP / IP reception process, and a storage unit 19-2. Alternatively, the network input processing unit 19-1 for storing the packet in the application data storage unit 19-5, the storage unit 19-2 for storing the packet, and the reception by the network input processing unit 19-1 stored in the storage unit 19-2 A TCP / IP transmission process is performed on the packet that has been processed, and the network output processing unit 19-3 that extracts the packet from the storage unit 19-2 and outputs the packet to the network. Application data storage unit 19-5 to be stored, application for executing arbitrary processing Configured with a tio emission processing unit 19-4.

  In the session relay apparatus 19-0 of the present embodiment, the network input processing unit 19-1 determines a session to which a packet input from the network belongs from an arbitrary combination set in advance, such as an IP address and a port number. After the IP reception process is completed, it is determined whether to execute the session relay process or the process by the application processing unit 19-4.

  When it is determined that the session relay process is to be performed, the network input processing unit 19-1 performs the transmission process in the network output processing unit 19-3 on the data stored in the storage unit 19-2. An instruction is issued to the network output processing unit 19-3. When the network input processing unit 19-1 determines to execute the processing by the application processing unit 19-4, the packet data stored in the storage unit 19-2 is copied to the application data storage unit 19-5, and the application processing unit 19-4 is notified of the arrival of data. The application processing unit 19-4 executes arbitrary processing.

  In the session relay device 19-0 of the present embodiment, the connection between the transmission terminal 10, the session relay device 19-0, and the reception terminal 20 is the same as that of the first embodiment, so the first embodiment is shown. This will be described with reference to FIG. Here, only differences from the first embodiment will be described.

  Next, processing by the session relay device 19-0 according to the eleventh embodiment will be described with reference to FIG. FIG. 18 is a flowchart showing an outline of processing of the session relay device according to the eleventh embodiment.

  The session relay device 19-0 starts processing when a packet from the transmission terminal 10 arrives at the network input processing unit 19-1.

  In step 18-1, the network input processing unit 19-1 calculates TCP and IP checksum values for the packet.

  In step 18-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the calculation result of the checksum value is equal to the checksum value stored in the packet, the process proceeds to step 18-3.

  In step 18-3, the network input processing unit 19-1 stores the packet in the storage unit 19-2, and the process proceeds to step 18-4.

  In Step 18-4, the network input processing unit 19-1 performs an IP reception process. However, the IP checksum value is not confirmed.

  In step 18-5, when the IP reception process is normally completed, the process proceeds to step 18-6. Otherwise, the packet is deleted from the storage unit 19-2 and the process ends.

  In step 18-6, the network input processing unit 19-1 refers to the packet stored in the storage unit 19-2, and performs a reception process according to the TCP rules on the packet.

  In step 18-7, when the TCP reception process is normally completed, the process proceeds to step 18-8. Otherwise, the process is terminated.

  In step 18-8, the network input processing unit 19-1 determines whether or not to perform session relay on the packet stored in the storage unit 19-2 by a combination of a preset IP address, port number, and the like. To do. When it is determined that the session relay is to be performed, the storage position of the packet is notified to the network output processing unit 19-3, and the process proceeds to Step 18-9.

  Otherwise, in step 18-15, the packet stored in the storage unit 19-3 is copied to the application data storage unit 19-5, and the packet is deleted from the storage unit 19-2.

  In step 18-16, the application processing unit 19-4 is notified of the storage position of the packet in the application data storage unit 19-5, and the process proceeds to step 18-17.

  In step 18-17, the application processing unit 19-4 refers to the application data storage unit 19-5 to realize arbitrary processing. Here, the processing content of the application processing unit 19-4 is not particularly defined. Thereafter, the process ends.

  In step 18-9, the network output processing unit 19-3 refers to the packet notified from the network input processing unit 19-1 and stored in the storage unit 19-2, and performs TCP transmission processing on the packet. carry out. If NAT is set in IP processing, NAT processing is performed. When the packet header needs to be updated in the TCP transmission process, the packet header stored in the storage unit 19-2 is overwritten and updated. However, for the checksum, the checksum value difference is calculated only for the updated part of the packet, and the checksum is updated to reflect the calculated difference in the checksum value stored in the packet.

  In step 18-10, when it is determined that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 18-11. If not, the process ends.

  In step 18-11, the network output processing unit 19-3 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 18-12. Otherwise, go to Step 18-13.

  In step 18-12, the network output processing unit 19-3 refers to the packet stored in the storage unit 19-2, and performs IP transmission processing on the packet.

  In Step 18-13, the network output processing unit 19-3 extracts the packet from the storage unit 19-2 and transmits the packet to the receiving terminal 20.

  In step 18-14, when it is confirmed that the receiving terminal 20 has received the packet normally, the packet is deleted from the storage unit 19-2.

  The above is the content of the session relay processing in the session relay device according to the eleventh embodiment.

  As described above, in this embodiment, it is possible to obtain high convenience by having a function of determining whether to perform session relay for an input packet or to perform processing by a custom application. become.

  FIG. 19 is a block diagram showing a configuration of a session relay device according to the twelfth embodiment of the present invention. In the present embodiment, the session relay device 21-0 receives a packet from the network and stores the packet in the storage unit 21-2. The storage unit 21-2 stores the arrived packet. The session determination unit 21-8 refers to the packet stored in the storage unit 21-2, determines the session to which the packet belongs, and determines whether to perform session relay processing or processing by the application processing unit 21-7. The reception processing up to the layer realizing session relay is performed on the packet stored in the storage unit 21-2, and the packet processing is instructed to the transmission protocol processing unit 21-4, or the application data storage unit 21- 6 is a reception protocol for copying data to 6 and notifying the application processor 21-7 of the arrival of the data. Transmission processing unit 21-3, a transmission protocol processing unit that performs transmission processing up to a layer that realizes session relay for a packet that is stored in the storage unit 21-2 and has been received by the reception protocol processing unit 21-3 21-4, a network output unit 21-5 that takes out a packet from the storage unit 21-2 based on instructions of the transmission protocol processing unit 21-3 and the reception protocol processing unit 21-4, and outputs the packet to the network. An application data storage unit 21-6 that stores data that can be referred to and operated, and an application processing unit 21-7 that performs arbitrary processing are configured.

  In the session relay device 21-0 of this embodiment, the session determination unit 21-8 determines a session to which a packet input from the network belongs from an arbitrary combination set in advance such as an IP address and a port number, and receives protocol processing After the TCP / IP reception processing in the unit 21-3 is completed, it is determined whether to perform session relay processing or processing by the application processing unit 21-7.

  If it is determined that the session relay process is to be performed, the reception protocol processing unit 21-3 performs the transmission process in the transmission protocol processing unit 21-4 on the data stored in the storage unit 21-2. Give instructions. When the session determination unit 21-8 determines to execute the processing by the application, the packet data stored in the storage unit 21-2 is copied to the application data storage unit 21-6, and the data is stored in the application processing unit 21-7. Notify of arrival. The application processing unit 21-7 implements arbitrary processing.

  Next, processing by the session relay device 21-0 according to the twelfth embodiment will be described with reference to FIG. FIG. 20 is a flowchart showing an outline of processing of the session relay device according to the twelfth embodiment.

  The session relay device 21-0 starts processing when a packet from the transmission terminal 10 arrives at the network input unit 21-1.

  In step 20-1, the network input unit 21-1 calculates TCP and IP checksum values for the packet.

  In Step 20-2, it is determined whether or not the checksum value calculation result is equal to the checksum value stored in the packet. If the checksum value is different, the packet is discarded and the process is terminated. If the checksum value calculation result is equal to the checksum value stored in the packet, the process proceeds to step 20-3.

  In step 20-3, the network input unit 21-1 stores the packet in the storage unit 21-2 and notifies the reception protocol processing unit 21-3 that the packet has been stored.

  In Step 20-4, the reception protocol processing unit 21-4 performs IP reception processing. However, the IP checksum value is not confirmed.

  In Step 20-5, when the IP reception process is normally completed, the process proceeds to Step 20-6. Otherwise, the packet is deleted from the storage unit 21-2 and the process ends.

  In step 20-6, the session determination unit 21-8 determines whether or not to perform session relay for the packet stored in the storage unit 21-2 by a combination of a preset IP address, port number, and the like. . When it is determined that the session relay is to be performed, the reception protocol processing unit 21-3 is notified of the storage position of the packet in the storage unit 21-2 and instructed to perform the transmission process of the packet. Otherwise, an instruction is given to copy the packet stored in the storage unit 21-2 to the application data storage unit 21-6.

  In step 20-7, the reception protocol processing unit 21-3 refers to the packet stored in the storage unit 21-2, and performs a reception process according to the TCP rules on the packet.

  In step 20-8, when the TCP reception process is normally completed, the process proceeds to step 20-9. Otherwise, the packet is deleted from the storage unit and the process is terminated.

  In step 20-9, based on the result determined by the session determination unit 21-8 in step 20-6, the session determination unit 21-8 performs session relay on the packet stored in the storage unit 21-2. If it is determined based on a combination of a preset IP address, port number, etc., the storage location of the packet is notified to the transmission protocol processing unit 21-4, and the process proceeds to Step 20-10. Otherwise, go to Step 20-17.

  In Step 20-17, the reception protocol processing unit 21-3 copies the packet stored in the storage unit 21-2 to the application data storage unit 21-6, and deletes the packet from the storage unit 21-2.

  In step 20-18, the application processing unit 21-7 is notified of the storage location of the packet in the application data storage unit 21-6.

  In step 20-19, the application processing unit 21-7 refers to the application data storage unit 21-6 and executes an arbitrary process. Here, the processing content of the application processing unit 19-4 is not particularly defined. Thereafter, the process ends.

  In step 20-10, the transmission protocol processing unit 21-4 refers to the packet notified from the reception protocol processing unit 21-3 and stored in the storage unit 21-2, and performs TCP transmission processing on the packet. carry out. If NAT is set in IP processing, NAT processing is performed. When it is necessary to update the packet header in the TCP transmission process, the packet header stored in the storage unit 21-2 is overwritten and updated. However, the checksum is updated so that the difference between the TCP and IP checksum values is calculated only for the updated portion of the packet, and the calculated difference is reflected in the checksum value stored in the packet.

  If it is determined in step 20-11 that the packet can be transmitted as a result of the TCP transmission process, the process proceeds to step 20-12. If not, the process ends.

  In Step 20-12, the transmission protocol processing unit 21-4 determines whether IP transmission processing is necessary or can be omitted. If IP transmission processing is necessary, the process proceeds to step 20-13. Otherwise, go to step 20-14.

  In step 20-13, the transmission protocol processing unit 21-4 refers to the packet stored in the storage unit 21-2 and performs IP transmission processing on the packet.

  In step 20-14, the transmission protocol processing unit 21-4 notifies the network output unit 21-5 of the location where the packet is stored, and instructs to output the packet.

  In step 20-15, the network output unit 21-5 extracts the packet from the storage unit 21-2 and transmits it to the receiving terminal 20.

  In step 20-16, when the network output unit 21-5 confirms that the transmitted packet is normally received by the receiving terminal 20, the network output unit 21-5 requests the transmission protocol processing unit 21-4 to delete the packet. In response to this, the transmission protocol processing unit 21-4 deletes the packet.

  The above is the content of the session relay processing in the session relay device according to the twelfth embodiment.

  As described above, in this embodiment, the session determination unit 21-8 determines whether to perform session relay on an input packet or to perform processing by a custom application, and the transmission protocol processing unit 21 -4 has a function of taking over the processing to the application processing unit 21-7 based on an instruction from the session determination unit 21-8, so that high convenience can be obtained.

  The session relay apparatus according to the present embodiment realizes each of the above components in hardware, and, for example, a session relay program (application) that performs relay processing on a computer processing apparatus (CPU) that can be controlled by a program. Can be provided as a system that implements the functions of the above-described components in software and executes the processing described below. This session relay program is stored in a magnetic disk, semiconductor memory, or other recording medium, loaded from the recording medium to a computer processing device, and necessary for timing analysis including delay time calculation by controlling the operation of the computer processing device. Each function is realized.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments, and various modifications can be made within the scope of the technical idea.

It is a block diagram which shows the structure of the session relay apparatus in a 1st Example. It is the block diagram which showed the flow of the data between the session relay apparatus in a 1st Example, a transmission terminal, and a receiving terminal. It is a flowchart which shows the outline | summary of a process of the session relay apparatus in a 2nd Example. It is a block diagram which shows the structure of the session relay apparatus in a 2nd Example. It is the block diagram which showed the flow of the data between the session relay apparatus in a 2nd Example, a transmission terminal, and a receiving terminal. It is a flowchart which shows the outline | summary of a process of the session relay apparatus in a 2nd Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 3rd Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 4th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 5th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 6th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 7th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in an 8th Example. It is a block diagram which shows the structure of the session relay apparatus in a 9th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 9th Example. It is a block diagram which shows the structure of the session relay apparatus in a 10th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 10th Example. It is a block diagram which shows the structure of the session relay apparatus in an 11th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in an 11th Example. It is a block diagram which shows the structure of the session relay apparatus in a 12th Example. It is a flowchart which shows the outline | summary of the process of the session relay apparatus in a 12th Example. It is a block diagram which shows the structural example of the conventional session relay apparatus. It is a block diagram which shows the other structural example of the conventional session relay apparatus.

Explanation of symbols

1-0, 4-0, 15-0, 17-0, 19-0, 21-0: Session relay device 1-1, 15-1, 19-1: Network input processing unit 1-2, 4-2 15-2, 17-2, 19-2, 21-2: storage unit 1-3, 15-3, 19-3: network output processing unit 4-1, 17-1, 21-1: network input unit 4-3, 17-3, 21-3: reception protocol processing unit 4-4, 17-4, 21-4: transmission protocol processing unit 4-5, 17-5, 21-5: network output unit 15-4 : Memory management unit 19-4, 21-7: Application processing unit 19-5, 21-6: Application data storage unit 21-8: Session determination unit

Claims (42)

In a session relay device that realizes communication between transmitting and receiving terminals by relaying data accompanied by TCP processing between a session for a transmitting terminal and a session for a receiving terminal,
It is composed of a storage unit for storing packets, a network input processing unit, and a network output processing unit,
The network input processing unit receives a packet from a network, stores packet data in the storage unit,
The network output processing unit calculates a checksum difference for the update portion of the stored data in the order of storage, and reflects the calculated difference in the checksum value stored in the stored data. Read and output the stored data ,
The session relay apparatus, wherein the network input processing unit and the network output processing unit have the same memory management authority . In a session relay device that realizes communication between transmitting and receiving terminals by relaying data accompanied by TCP processing between a session for a transmitting terminal and a session for a receiving terminal,
A storage unit for storing packets, a network input unit, a reception protocol processing unit, a transmission protocol processing unit, and a network output unit,
The network input unit receives a packet from the network, stores the packet data in the storage unit,
In the order in which the reception protocol processing unit is stored, a reception process is performed on the stored data,
The transmission protocol processing unit calculates a checksum difference for the updated portion of the stored data, and reflects the calculated difference in the checksum value stored in the stored data;
The network output unit reads and outputs the data ,
The session relay device, wherein the reception protocol processing unit and the transmission protocol processing unit have the same memory management authority . 3. The session relay process is realized by operating on a general-purpose computer equipped with an operating system and having at least one of a memory management authority and a processing authority equivalent to the operating system. Session relay device. When IP is included in the protocol to be processed,
The session relay apparatus according to claim 1, further comprising means for determining whether or not an IP layer transmission process is necessary. 5. The session relay apparatus according to claim 4 , further comprising means for selectively performing only a process common to all packets among the processes of the IP layer. Whether IP transmission processing is necessary or unnecessary is determined to be necessary when processing with IP address translation such as NAT or IP masquerade is set, and is determined to be unnecessary when this is not set The session relay device according to claim 4 , wherein Whether the IP transmission processing is necessary or unnecessary is determined when an ICMP redirect arrives, and is determined to be unnecessary again after the processing of the IP transmission unit for the redirect is performed. 4. The session relay device according to 4 . Whether IP transmission processing is necessary or unnecessary is determined as necessary if the physical address corresponding to the IP address of the communication partner is not known, and is unnecessary if the physical address corresponding to the IP address of the communication partner is known The session relay device according to claim 4 , wherein the session relay device is determined. 6. The session relay apparatus according to claim 5 , wherein, in the IP layer processing, only the IP header checksum calculation is selectively performed. 6. The session relay apparatus according to claim 5 , wherein only the process involving IP address conversion, such as NAT, is selectively performed among the processes of the IP layer. Targeting protocol processing that calculates the checksum value of the payload part, the network input processing unit performs checksum calculation at the time of reception below the target layer in session relay, and the network output processing unit updates the packet 2. The session relay apparatus according to claim 1, wherein when the received information is received, a checksum value is calculated from information in a header portion. Targeting protocol processing to calculate the checksum value of the payload part, the network input processing unit performs checksum calculation at the time of reception below the target layer in session relay, and the transmission protocol processing unit 3. The session relay device according to claim 2, wherein, when updated, the checksum value is calculated from the information of the header portion. The session relay apparatus according to claim 1, wherein the network input processing unit determines a session to which a packet input from the network belongs, and performs session relay according to the determination result. It has a session determination unit,
The session relay apparatus according to claim 2, wherein the session determination unit determines a session to which a packet input from a network belongs, and performs session relay according to the determination result. Operating in general purpose computing machine on which the operating system is installed, according to claim 13 or claim 14, characterized in that to realize at least one has a session relay processing of the processing rights as the operating system and the same memory management authority Session relay device. In the case that contains the IP processing protocol, session relay apparatus according to claim 13 or claim 14, characterized in that it comprises means for determining whether necessary or unnecessary transmission process of the IP layer. 17. The session relay apparatus according to claim 16 , further comprising means for selectively performing only a process common to all packets among the processes of the IP layer. Whether IP transmission processing is necessary or unnecessary is determined to be necessary when processing with IP address translation such as NAT or IP masquerade is set, and is determined to be unnecessary when this is not set The session relay device according to claim 16 , wherein Whether or not IP transmission processing is necessary or not is determined when an ICMP redirect arrives at the session relay device, and after the processing of the IP transmission unit for the redirect is determined to be unnecessary again The session relay device according to claim 16 . Whether IP transmission processing is necessary or unnecessary is determined as necessary if the physical address corresponding to the IP address of the communication partner is not known, and is unnecessary if the physical address corresponding to the IP address of the communication partner is known The session relay device according to claim 16 , wherein the session relay device is determined. 18. The session relay apparatus according to claim 17 , wherein, in the IP layer processing, only IP header checksum calculation (definition required) is selectively performed. 18. The session relay apparatus according to claim 17 , wherein, among IP layer processes, only a process involving translation of an IP address such as NAT is selectively performed. For protocol processing that calculates the checksum value of the payload part,
The session relay apparatus according to claim 13 or 14 , wherein the network input processing unit performs checksum calculation at the time of reception for at least two layers below a target layer for session relay.   A session relay method for realizing communication between transmitting and receiving terminals by relaying data accompanied by TCP processing between a session for a transmitting terminal and a session for a receiving terminal,
  A network input process for receiving a packet from the network and storing the packet data in the storage unit;
  The checksum difference is calculated for the updated portion of the stored data in the order of storage, the calculated difference is reflected in the checksum value stored in the stored data, and the stored data is It has network output processing to read and output,
A session relay method, wherein the network input process and the network output process are executed using the same memory management unit.   A session relay method for realizing communication between transmitting and receiving terminals by relaying data accompanied by TCP processing between a session for a transmitting terminal and a session for a receiving terminal,
  Network input processing for receiving packets from the network and storing the packet data in the storage unit;
  A reception protocol process for performing a reception process on the stored data in the order of storage;
  A transmission protocol process for calculating a checksum difference for the updated portion of the stored data and performing a process of reflecting the calculated difference in the checksum value stored in the stored data;
A network output process for reading out and outputting the stored data;
A session relay method, wherein the network input process, the reception protocol process, and the transmission protocol process are executed using the same memory management unit. When IP is included in the protocol to be processed,
  26. The session relay method according to claim 24 or 25, further comprising a process of determining whether or not an IP layer transmission process is necessary. 27. The session relay method according to claim 26, further comprising a process of selectively performing only a process common to all packets among the processes of the IP layer. Whether IP transmission processing is necessary or unnecessary is determined to be necessary when processing with IP address translation such as NAT or IP masquerading is set, and is determined to be unnecessary when this is not set 27. The session relay method according to claim 26, wherein: Whether the IP transmission processing is necessary or unnecessary is determined when an ICMP redirect arrives, and is determined to be unnecessary again after the processing of the IP transmission unit for the redirect is performed. 26. The session relay method according to 26. Whether IP transmission processing is necessary or unnecessary is determined as necessary if the physical address corresponding to the IP address of the communication partner is not known, and is unnecessary if the physical address corresponding to the IP address of the communication partner is known 27. The session relay method according to claim 26, characterized in that: 28. The session relay method according to claim 27, wherein, in IP layer processing, only IP header checksum calculation is selectively performed. 28. The session relay method according to claim 27, wherein only a process involving IP address conversion such as NAT is selectively performed among processes of the IP layer. Targeted for protocol processing to calculate the checksum value of the payload part, in the network input processing, checksum calculation was performed at the time of reception below the target layer in session relay, and the packet was updated in network output processing 25. The session relay method according to claim 24, wherein a checksum value is calculated using information in a header part. 25. The session relay method according to claim 24, wherein in the network input process, a session to which a packet input from a network belongs is determined, and session relay is performed according to the determination result. 32. The session relay method according to claim 30 or 31, wherein, when an IP is included in a protocol to be processed, it is determined whether or not an IP layer transmission process is necessary. 36. The session relay method according to claim 35, wherein, of IP layer processing, only processing common to all packets is selectively performed. Whether IP transmission processing is necessary or unnecessary is determined to be necessary when processing with IP address translation such as NAT or IP masquerading is set, and is determined to be unnecessary when this is not set 36. The session relay method according to claim 35, wherein: Whether the IP transmission processing is necessary or unnecessary is determined when an ICMP redirect arrives, and is determined to be unnecessary again after the processing of the IP transmission unit for the redirect is performed. 35. The session relay method according to 35. Whether IP transmission processing is necessary or unnecessary is determined as necessary if the physical address corresponding to the IP address of the communication partner is not known, and is unnecessary if the physical address corresponding to the IP address of the communication partner is known 36. The session relay method according to claim 35, wherein the session relay method is determined. 37. The session relay method according to claim 36, wherein only IP header checksum calculation is selectively performed in the IP layer processing. 37. The session relay method according to claim 36, wherein, of IP layer processing, only processing such as NAT that involves IP address translation is selectively performed. For protocol processing that calculates the checksum value of the payload part,
32. The session relay method according to claim 30 or 31, wherein, in the network input process, checksum calculation at the time of reception is performed for at least two layers below the target layer for session relay.

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