On Sat, 24 Feb 2007, Jon Smirl wrote: > On 2/24/07, Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > Also, Jon was hitting some problems with tcpdump and Paolo's libpcap, > > so let's keep one more revision stable to help them to figure this out > > and bring libpcap into shape. They may yet find a kernel bug too. > > I wish the bus numbers were stable across boots. I have five buses and > I don't see any pattern in how the bus numbers get assigned.
If you don't move things around, they should be fairly stable. The way bus numbers are assigned is pretty simple: Each time a new bus is registered it gets the first available number. Registration occurs in the order of driver probing, which depends on two things: PCI device discovery and driver loading. Neither of those should vary too much between boots. If you know what to look for, you can follow the progress in detail in the dmesg log. > The wireshark packet decoder needs a lot of work. It's not broken, but > there are huge amounts of code that need to be written just to finish > decoding the low level protocol. The decoder needs to be much further > along before I would feel good in saying that the lower layers do what > we want. Finishing this is going to need some help from USB experts, > there are a lot of obscure things in the USB protocol that I don't > know what they do. Post your questions and we'll try to answer them. > For example, as far as I can tell there is no info in the capture > packet stream describing the attached devices unless I so something > like "lsusb -v" while data is being captured. That's true for libpcap in general, isn't it? If you capture an Ethernet session using tcpdump, the packet stream doesn't contain information about the remote hosts unless you do a DNS lookup or something similar. > I want to write a > decoder for device ID 2001:3c00, a ralink wireless dongle. I can't do > this because I can't tell the device ID of the streams being recorded. > Somebody (libpcap or the kernel) needs to automatically query the > descriptors when the monitor stream is first opened so that the > descriptor data will get recorded and I can tell what devices are > present. It would be best if this data was the first data recorded in > every session. It also needs to track hot plugs. This should be done by the user program, just the way tcpdump does it. When you run the capture program you tell it what device you're interested in. The program looks up the device ID and finds the device's address; then it can filter just the packets for that address. I guess that's built into libpcap. Tracking hot plugs doesn't seem necessary. It's like saying that tcpdump should track every time a new computer is added to your network. > At a minimum I think we should have decoders for HID, audio and mass > storage working before committing everything to stone. Those three > device classes each use USB quite differently. Add hubs to the list, plus general Chapter-9 requests. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
