tcpdump mailing list archives
Re: DLT_ request
From: Scott Deandrea <sdeandrea () apple com>
Date: Sun, 11 Dec 2016 08:32:51 -0800
The deviceLocation is an Apple specific property that describes the bus topology to which the device is connected. The most significant byte contains the bus number; a unique value given to a host controller and also used when generating the interface numbers. The following nibbles correspond to the port number(s) through which the device is connected. For example: FaceTime HD Camera (Built-in)@1a110000 <class IOUSBHostDevice, id 0x10000f263, registered, matched, active, busy 0 (9 ms), retain 24> The bus number is 0x1a and the camera is connected to port 1 of the hub that is connected to root port 1 on the host controller. The ioFrameCount field, though not currently supported, is intended to be used for isochronous endpoints as their I/O model is slightly different in that you pass down a vector describing I/O for multiple USB frames. On completion you would receive the header followed by and ioFrameCount array of isochronous header followed by the packet data. The isochronous header is currently defined as follows: struct { // Control information uint32_t frameHeaderLength; // Frame information uint32_t frameLength; uint64_t frameNumber; uint64_t ioTimestamp; } __attribute__((packed, aligned (sizeof(uint32_t)))); —scott
On Dec 10, 2016, at 7:00 PM, Guy Harris <guy () alum mit edu> wrote: On Dec 9, 2016, at 1:37 PM, Scott Deandrea <sdeandrea () apple com> wrote:uint32_t deviceLocation; // locationID of the deviceSo is a locationID something defined by a USB specification, by Apple in a fashion specific to Darwin, or something else? What is the format of a locationID?uint32_t ioFrameCount; // number of isoch frames followingSo would that value affect the interpretation of the payload and, if so, how?
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Current thread:
- Re: DLT_ request, (continued)
- Re: DLT_ request Guy Harris (Dec 09)
- Re: DLT_ request Scott Deandrea (Dec 09)
- Re: DLT_ request Guy Harris (Dec 10)
- Re: DLT_ request Scott Deandrea (Dec 11)
- Re: DLT_ request Guy Harris (Dec 11)
- Re: DLT_ request Scott Deandrea (Dec 12)
- Re: DLT_ request Guy Harris (Dec 12)
- Re: DLT_ request Scott Deandrea (Dec 12)
- Re: DLT_ request Guy Harris (Dec 09)
- Re: DLT_ request Guy Harris (Dec 10)
- Re: DLT_ request Scott Deandrea (Dec 11)
- Re: DLT_ request Guy Harris (Dec 11)
- Re: DLT_ request Scott Deandrea (Dec 12)
- Re: DLT_ request Guy Harris (Dec 12)
- Re: DLT_ request Scott Deandrea (Dec 13)