JP2002312258A - Usb monitor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter function not receiving invalid transaction to transaction of a specific ADDRESS/ENDPOINT, and receiving only valid transaction. SOLUTION: This USB monitor system monitoring USB communication data and recording packet data into a record means has a decision means distinguishing between the valid transaction and the invalid transaction and records only the packet data of the valid transaction into the record means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention monitors data on a universal serial bus (hereinafter abbreviated as USB) connecting a personal computer and its peripheral devices, and receives and captures only necessary data (recording media such as RAM and HD). To a protocol analyzer that has the function of

[0002]

2. Description of the Related Art Conventionally, as one of methods for determining a failure location when a failure occurs in a USB communication line, there is a method for determining whether or not the line data is correct. In this method, data on a communication line is received in units of frames using a protocol analyzer, and the normal / abnormal of a bit field value or a frame sequence is determined based on the data, and is used to isolate a line fault location. .

[0003] USB communication is performed between a host that controls communication and a terminal that is positioned as a function that operates dependently, and communication is performed at a transfer rate of 1.5 Mbps or 12 Mbps. Further, the host specifies a function to be communicated based on information called ADDRESS / ENDPOINT and performs data communication.

[0004] There are ten types of packets used in these communications as shown in FIG. The USB communication has a transfer method (bulk, control, interrupt, and isochronous) called four types of transactions, and there are roughly two types of transaction formats.

When analyzing upper USB data, a transaction format effective for the analysis (hereinafter referred to as an effective transaction) includes a "token packet", a "DATA packet", a "handshake packet", or a "token packet" or "token packet" shown in FIG. DATA packet ".

[0006] Other than this configuration, the host and the function discard the transaction as an invalid transaction for analysis (hereinafter referred to as an invalid transaction). The protocol analyzer has a filter function shown in FIG. 3 for receiving only necessary data. When measuring a USB line,
A packet type filter function for receiving only a specific USB packet shown in FIG. 4 and a specific ADDR shown in FIG.
Equipped with a filter function to receive only ESS / ENDPOINT communication.

[0007] The filter function for each packet type compares the packet type for each packet and records it on a recording medium when the packet type matches the target packet. ADDRESS / E
When determining the token packet, the NDPOINT filter function registers the ADDRESS value and the ENDPOINT value in the packet in the filter processing unit, and thereafter continues reception and recording in the RAM until the handshake packet is determined.

[0008]

If the transfer speed of the upper protocol data of the USB is extremely lower than 1.5 Mbps or 12 Mbps, the USB in which the upper protocol data exists
The transaction accounts for an extremely small percentage of all USB packets. This indicates that the majority is occupied by invalid transaction formats and frame start packets (SOF packets).

[0009] USB upper protocol data is DATA0.
Or, because it exists in DATA1, it is possible to receive only DATA0 and DATA1 with the filter for each packet type, but the direction and validity of data and ADDRESS / ENDPOINT information do not exist in only DATA0 and DATA1 packets. It is difficult to judge the upper protocol data.

[0010] Further, even if the ADDRESS / ENDPOINT filter shown in FIG. 6 receives only the specified ADDRESS / ENDPOINT transaction, the invalid transaction format (transaction without DATA0 or DATA1) occupies most of the received data. Therefore, it takes time to determine and analyze the upper protocol data.

An object of the present invention is to provide a specific ADDRESS / ENDPOINT
An object of the present invention is to provide a filter function for receiving only an effective transaction without receiving an invalid transaction for the transaction of (i).

[0012]

In order to solve the above-mentioned problems, a USB communication data is monitored, and in a monitor method for recording the packet data in a recording means, a discrimination means for discriminating between a valid transaction and an invalid transaction. 30 is provided, and only the packet data of the valid transaction is recorded in the recording means, so that the analysis can be performed in a short time. (Claim 1)

Further, the determination means makes a determination according to a type of a packet following the token packet. (Claim 2) The determining means determines that the packet is a valid transaction only when the packet following the token packet is a data packet. (Claim 3) In addition, the determination means determines that the packet following the token packet is a valid transaction only when the packet following the data packet is a handshake packet. this is,
This is a case where the transaction format is isochronous. (Claim 4)

In addition, if the next packet cannot be determined within a predetermined period after the determination of the token packet, a means for processing as an invalid transaction is provided. The token can be deleted by returning the pointer to the position indicated by the BAK (storage pointer). (Claim 5)

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 is a diagram illustrating a configuration of a USB monitor including a filter for each packet type according to an embodiment of the present invention. In FIG. 7, reference numeral 1 denotes a host for controlling communication, and reference numeral 2 denotes a terminal positioned as a function. Reference numeral 3 denotes a protocol analyzer, which includes an ADDREES / ENDPOINT (31), an effective transaction filter processing unit (33), and a packet type-specific filter processing unit (3).
2) Filter processing unit (30), RAM (34), CPU (3
5), a storage medium (36), and a display device (37).

In the USB line, between the host 1 and the terminal 2, data to be transmitted bidirectionally is selected by a filter function, and received by a protocol analyzer, and an ADDRESS / ENDPOINT filter section 31 in a filter processing section 30 is received.
The effective transaction filter processing unit 33 is arranged at the subsequent stage.

Transactions received from the line include:
A valid transaction whose transaction format is ("token packet", "DATA packet", "handshake packet") and ("token packet", "DATA packet"), and a transaction format other than ("token packet", "DATA packet") ｛(“Token packet” “Handshake packet”), (“Token packet” “Token packet”)
Equal invalid transactions are included. ADDR
In the ESS / ENDPOINT filter unit 31, the received transaction is passed to the valid transaction filter unit 33 one packet at a time.

The determination process of the valid transaction filter processing section 33 is executed as follows. The processing includes a flag indicating that the token packet has been determined (hereinafter, referred to as a token flag), a write pointer to the recording medium 36 (hereinafter, referred to as a write pointer), and the position of the write pointer. Prepare the pointer BAK.

Writing to a recording medium is performed by a writing pointer as shown in FIG. ADDRESS / ENDPOINT
The token flag is determined from the output of the filter, and it is determined whether a token packet was received last time. If the token flag is OFF (the state where the token packet has not been received previously), the packet type is determined from the PID field.

If the packet is a "token",
The pointer position of the SYNC pattern is saved in BAK, and the token flag is turned ON. After that, the packet data is written to the recording medium.

In the case of "other than a token" as judged by the PID field, packet data is written unconditionally. If the token flag is ON (the state where the token packet has been received previously), the packet type of the PID field is determined. If the result is "DATA0 / 1", the token flag is turned off and packet data is written.

If "other than DATA0 / 1" and "other than token", the token flag is turned off, and this transaction is regarded as invalid, as shown in FIG.
Return the write pointer to the position indicated by BAK.

If "except for DATA0 / 1" and "token", it indicates that "tokens" have come in succession, so that the last "token" in succession is left as shown in FIG. , Return the write pointer to the position indicated by BAK,
This token packet data is written to a recording medium.

If a timeout occurs after the determination of the "token" (when no determination can be made after the lapse of 16 clock counts), as shown in FIG. The token information is deleted by returning the pointer to the position indicated by BAK.

Next, the overall processing flow of the present invention is shown in FIG.
This will be described with reference to FIG. First, the bidirectional communication data between the host 1 and the terminal 2 is converted into the AD data of the filter processing unit 30 constituting the protocol analyzer 3.
The DRES / ENDPOINT filter processing unit 31 outputs. (Step S1) Next, with respect to the output from the ADDRES / ENDPOINT filter processing unit 31, it is determined that the timeout has not been established and the SYNC pattern has been recognized. (Step S2) If the judgment in step S2 is True, a token flag judgment is performed. (Step S3)-If the judgment in step S3 indicates that the token flag is ON (the last time a token packet has been received),
It is determined whether the packet type in the PID field is DATA0 / 1. (Step S4) ・ Trur (the packet type is DATA0 /
1) In the case, turn off the token flag. (Step
S10) After turning off the token flag in step S10, the packet data is written to the storage medium 36, and the write pointer is updated. (Step S11)

If the result of determination in step S4 is Faise (the packet type is not DATA0 / 1), it is determined whether the packet type in the PID field is a token. (Step S5) If the determination in step S5 is True (the packet type is token), the position of the write pointer is returned to BAK.
(Step S6) After returning the position of the write pointer to BAK in step S6, the packet data is written to the storage medium 36, and the write pointer is updated. (Step S7)

If the determination in step S5 is False (the packet type is other than DATA0 / 1 and other than a token), the token flag is turned off. (Step S8) The reason why the token flag is turned off in step S5 is a result of determining that this transaction is invalid, so that the write pointer is returned to the position indicated by BAK. (Step S9)

If the token flag is determined in step S3
If it is OFF (the state where the token packet has not been received last time), it is determined whether or not the packet type in the PID field is a token. (Step S12)-The judgment in Step S12 is True (packet type token)
In the case of, the pointer position of SYNC is stored in BAK.
(Step S13) • After storing the SYNC pointer position in BAK in step S12, the token flag is turned ON. (Step S14) After the token flag is turned ON in Step S14, packet data is written to the medium 36 and the write pointer is updated. (Step S15) If the determination in Step S12 is False (other than the packet type token), the packet data is written to the storage medium 36 and the write pointer is updated. (Step S15)

If the determination in step S2 is False, it is determined whether the packet type in the PID field is a token. (Step S16) If the determination in Step S16 is True (the packet type is token), the write pointer is returned to the position indicated by BAK. (Step S17) After returning the write pointer to the position indicated by BAK in step S16, the token flag is turned off. (Step S18) If the judgment in step S16 is False (the packet type is other than token), the token flag is turned off.
(Step S18)

[0030]

According to the first aspect of the present invention, in the monitor method for monitoring USB communication data and recording the packet data in the recording means, the discrimination means 30 for discriminating between a valid transaction and an invalid transaction is provided. By recording only the packet data of the valid transaction in the recording means, the analysis can be performed in a short time, the upper data of USB can be easily identified, and the recording efficiency of the received data can be improved.

In the invention according to the second aspect, the determination means can easily determine whether the transaction is a valid transaction or an invalid transaction according to the type of a packet following the token packet. Further, in the invention according to claim 3, the determination means can determine that the transaction following the token packet is a valid transaction only when the packet is a data packet. Further, in the invention according to claim 4, the determination means determines that the transaction following the token packet is a valid transaction only when the packet following the data packet is a handshake packet. I do.

According to the fifth aspect of the present invention, when a next packet cannot be determined within a predetermined period after a token packet is determined, a means for processing as an invalid transaction is provided. BAK the write pointer in case of only invalid transaction
By returning to the position indicated by, the token can be deleted.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a packet used for USB communication.

FIG. 2 is a diagram showing a configuration of a transaction format used for USB communication.

FIG. 3 is a diagram illustrating a configuration of a conventional filter for each packet type.

FIG. 4 is a diagram for explaining an operation of a conventional filter for each packet type.

FIG. 5 is a diagram for explaining the operation of an ADDRESS / ENDPOINT filter.

Fig. 6: Conventional packet type filters and ADDRESS / EN
It is a figure for comparing the operation of a DPOINT filter.

FIG. 7 is a diagram for explaining the operation of the filter for each packet type according to the present invention.

FIG. 8 is a diagram illustrating an example of writing to a storage medium.

FIG. 9 is a diagram illustrating an example of pointer operation in the RAM when the transaction format is “token” or “handshake”.

FIG. 10 is a diagram illustrating an example of pointer operation in a RAM when the transaction format is “token”;

FIG. 11 is a diagram showing an example of pointer operation in the RAM when the transaction format is “token”.

FIG. 12 is a flowchart showing the overall processing procedure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host 2 Terminal (function) 3 Protocol analyzer 30 Filter processing unit 31 ADDRESS / ENDPOINT filter processing unit 32 Filter processing unit by packet type 33 Effective transaction filter processing unit 34 RAM 35 CPU 36 Storage medium 37 Screen display

Claims (5)

[Claims] 1. A monitoring method for monitoring USB communication data and recording the packet data on a recording means, comprising: a discriminating means for discriminating between a valid transaction and an invalid transaction; A USB monitor method characterized by recording on a recording means. 2. The USB monitor method according to claim 1, wherein said determination means makes a determination according to a type of a packet following the token packet. 3. The USB monitor method according to claim 2, wherein said determination means determines that the transaction following the token packet is a valid transaction only when the packet is a data packet. 4. The method according to claim 1, wherein the determination unit determines that the transaction is a valid transaction only when a packet following the token packet is a data packet and a packet following the data packet is a handshake packet. The USB monitor method according to claim 2. 5. The system according to claim 1, further comprising means for processing as an invalid transaction when a next packet cannot be determined within a predetermined period after the token packet is determined. The USB monitor method according to item 1.