On 22:25 Tue 24 May , N??meth M??rton wrote: > Greg KH wrote: > > On Tue, May 24, 2011 at 08:28:13PM +0200, N??meth M??rton wrote: > >> Hi, > >> > >> I'm looking for the USBIP protocol documentation. I found that > >> there was already a discussion about the USBIP protocol and > >> there is some draft about it: > >> > >> * http://marc.info/?l=linux-kernel&m=122001863119269&w=2 > >> * http://www.kernel.org/pub/linux/kernel/people/willy/usbip/usbip-protocol-draft-1 > >> > >> Unfortunately I couldn't found any detailed protocol documentation > >> on the project homepage: > >> > >> * http://usbip.sourceforge.net/#documentation > >> > >> Do you know any follow-up on the USBIP protocol documentation? > > > > I think the code is the "real" documentation. I concur! > If it is, then I need to read it in the right way, through it is not an easy task. > I tried to find the points in the USBIP kernel code where opening, sending, > receiving and closing of the TCP connection takes place. I took all function names > from linux/net.h and I found the following places so far: > > $ grep -n -E > 'sock_wake_async|sock_register|sock_unregister|sock_create|sock_create_kern|sock_create_lite|sock_release|sock_sendmsg|sock_recvmsg|sock_map_fd|sockfd_lookup|sockfd_put|net_ratelimit|kernel_sendmsg|kernel_recvmsg|kernel_bind|kernel_listen|kernel_accept|kernel_connect|kernel_getsockname|kernel_getpeername|kernel_getsockopt|kernel_setsockopt|kernel_sendpage|kernel_sock_ioctl|kernel_sock_shutdown|SHUT_' > linux-2.6/drivers/staging/usbip/* > > linux-2.6/drivers/staging/usbip/stub_dev.c:201: kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR); > linux-2.6/drivers/staging/usbip/stub_dev.c:216: sock_release(ud->tcp_socket); > linux-2.6/drivers/staging/usbip/stub_tx.c:263: ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, > linux-2.6/drivers/staging/usbip/stub_tx.c:338: ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov, > linux-2.6/drivers/staging/usbip/usbip_common.c:382: result = kernel_sendmsg(sock, &msg, &iov, 1, size); > linux-2.6/drivers/staging/usbip/usbip_common.c:384: result = kernel_recvmsg(sock, &msg, &iov, 1, size, > linux-2.6/drivers/staging/usbip/vhci_hcd.c:845: kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR); > linux-2.6/drivers/staging/usbip/vhci_hcd.c:858: sock_release(vdev->ud.tcp_socket); > linux-2.6/drivers/staging/usbip/vhci_tx.c:119: ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, 3, txsize); > linux-2.6/drivers/staging/usbip/vhci_tx.c:189: ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, 1, txsize); > > I guess this is not all, there is also a protocol defined to the user-space world. Very true, and part of what is taking place is a unification of the userspace and kernel protocols. Then there will be some degree of documentation. Mainly in the form of packet diagrams to show on-wire communication. > > Note a number of developers are actively working on changing the protocol > > and fixing it up based on Matthew's previous comments. Look at the > > thread on the usbip project's mailing list for a few details. More will > > be in the patches produced by the developers. > > I had a look at the usbip-devel mailing list archive at > http://sourceforge.net/mailarchive/forum.php?forum_name=usbip-devel and found > a thread where I could find some protocol description also: > > * http://sourceforge.net/mailarchive/message.php?msg_id=27240940 > > The current protocol implementation is based on top of TCP. In the message > at http://marc.info/?l=linux-kernel&m=122001883519653&w=2 the SCTP is mentioned. > Have anybody worked on finding out what benefits the SCTP could give to USBIP > and what would be the drawbacks? I think sctp would be interesting, but as greg said, and I tend to agree, this is the least of usbip's problems. (Maybe eliminating the need to interact w/ windows would be a good project ;) jk! -matt -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
