[jira] [Comment Edited] (PLC4X-30) [S7] Implement symbolic addressing

["Christofer Dutz (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PLC4X-30?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17208680#comment-17208680 ] 

Christofer Dutz edited comment on PLC4X-30 at 10/6/20, 11:55 AM:
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If you get one of the really recent versions of Wireshark, or if you install the s7comm plus disector, you can actually read most of the packets. 

We did quite some research on this topic and have come to the conclusion, that in PLC4X we will probably only be able to implement a passive-mode driver. The reason for this is that we would have to have access to some crypto keys which we don't have access to in order to actively communicate. While closed source driver vendors have the "benefit", that probably Siemens would have to do stuff that's forbidden in order to prove that the others did something which is forbidden. As an open-source project, we don't have this "benefit". 

Perhaps if we happen to find a way to legally create the hashes needed in S7comm plus, I don't see an active driver coming soon.

And I also doubt that with this we would be able to do some of the optimizations we can with the old S7 driver. Even if we had a S7comm plus driver, I still think - if possible- it would be less strain on the PLC to request a lot of values using the old driver.

Chris


was (Author: cdutz):
If you get one of the really recent versions of Wireshark, or if you install the s7comm plus disector, you can actually read most of the packets. 

We did quite some research on this topic and have come to the conclusion, that in PLC4X we will probably only be able to implement a passive-mode driver. The reason for this is that we would have to have access to some crypto keys which we don't have access to in order to actively communicate. While closed source driver vendors have the "benefit", that probably Siemens would have to do stuff that's forbidden in order to prove that the others did something which is forbidden. As an open-source project, we don't have this "benefit". 

Perhaps if he happen to find a way to legally create the hashes needed in S7comm plus, I don't see an active driver coming soon.

And I also doubt that with this we would be able to do some of the optimizations we can with the old S7 driver. Even if we had a S7comm plus driver, I still think - if possible- it would be less strain on the PLC to request a lot of values using the old driver.

Chris

> [S7] Implement symbolic addressing
> ----------------------------------
>
>                 Key: PLC4X-30
>                 URL: https://issues.apache.org/jira/browse/PLC4X-30
>             Project: Apache PLC4X
>          Issue Type: Improvement
>          Components: Driver-S7
>            Reporter: Christofer Dutz
>            Priority: Major
>
> Currently we only support direct addressing. However usually symbolic addressing is used where a variable or memory area is represented via a symbolic name and TIA takes care of compiling the symbol table when compiling the PLC program. 
> Unfortunately a description of this symbolic addressing is nowhere to be found.



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