Re: [Libusb-devel] A small set of questions :-)

[Athanasios A. <th...@at...>]

Hello Johannes

Excuse me for the late reply but things have been busy around here.


>>2. From a small application that i have developed, that needs to "dive" 
>>into the whole set of structures defined in usb.h i noticed that the 
>>Busses and Devices structures are Double Linked Lists, while the 
>>interfaces that "sit" on every configuration are just arrays? Is that 
>>right? For example if the number of interfaces on a config_descriptor is 
>>2 i can safely assume that there are 2 consecutive struct usb_interface 
>>structures on the *interface pointer?
>>Why not make everything a Double Linked List?
>>    
>>
>
>Because it's easier to index an array than walk a linked list?
>  
>
To be honest i prefer the DL list way :-)

>>3.What are the points that i can use to monitor USB traffic? For 
>>example, can i monitor all the traffic that goes by a HUB or i must 
>>explicitly monitor the traffic that goes through a function? (or endpoint?)
>>
>>4.In the case i can only monitor the traffic through a function (or 
>>endpoint?), is it enough to just "claim the interface" and then do 
>>periodic "bulk_reads"?
>>    
>>
>
>You cannot monitor any traffic using libusb right now.
>
>libusb is only used to initiate traffic.
>  
>
Is there any provision for "hooks" or callbacks provided by libusb for 
the future?


>  
>
>>5. Just out of curiosity, isnt it possible to monitor USB traffic 
>>through a "tee" on the appopriate file? In this case isnt it possible to 
>>monitor the traffic through a hub and through an independent device? 
>>Assuming ofcourse that the device is also "visible" through a file as is 
>>the "standard" way in Linux.
>>    
>>
>
>There is a recently added interface to Linux called usbmon, but libusb
>has no support for this.
>
>JE
>  
>
Yes i have seen it, the guy has done remarkable job, do you think 
something like that would be incorporated in the kernel at some point?


All the best.
thanOS