Re: Example network protocol implementation
On Sat, 9 Dec 2006, Vishal Patil wrote: Could someone point me to an example that shows a SIMPLE network protocol implemented over TCP/IP inside the FreeBSD kernel. I think I could look at the NFS client driver but is there an example simpler than that. Also is there a guide explaining how to go about developing TCP/IP based network protocols for FreeBSD. Thanks Here are some consumers of sockets in the kernel: - NFS client, which creates and connects both UDP and TCP sockets, uses them for I/O, etc. - NFS server, which uses UDP and TCP sockets for I/O. Unlike the NFS client, it doesn't open the sockets in kernel, rather, it relies on a user process (nfsd) passing validated sockets into the kernel. - System V streams (dev/streams), which uses socket pairs to implement streams. Does creation and I/O. - fifofs, which implements POSIX fifos using a pair of UNIX domain sockets. Again, does creation and I/O. - portalfs, which implements the portal file system using sockets. - ng_ksocket, which provides a netgraph interface to sockets in the kernel. - netncp, which provides an NCP RPC interface over SPX/IPX for nwfs. - netsmb, which provides an SMB RPC interface over TCP/IP for smbfs. - rpclnt, which is used by the nfs4client, and is functionally similar to the NFS client RPC code for NFS2/NFS3 in nfsclient. - bootp_subr.c and krpc_subr.c, which are used by the NFS root code to set up NFS access during a diskless boot: they perform the bootp exchange to retrieve an IP address, and then the necessary RPC mount protocol to query a root file handle to set up the NFS client for the file system root. All of these examples have upsides and downsides, and vary in maturity. I'd probably start by looking at the NFS client and fifofs. One of the biggest questions you'll need to answer is what your event model is and how it will relate to any worker threads you may have. Many of the in-kernel socket consumers use socket upcalls to get direct notifications of socket events from within the network stack, allowing for fast socket draining and TCP acking. On the other hand, in the netisr/ithread context, you can't perform blocking memory allocation and disk I/O, so if that will be involved, you'll need worker threads in the style of the NFS server. Robert N M Watson Computer Laboratory University of Cambridge ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Example network protocol implementation
Could someone point me to an example that shows a SIMPLE network protocol implemented over TCP/IP inside the FreeBSD kernel. I think I could look at the NFS client driver but is there an example simpler than that. Also is there a guide explaining how to go about developing TCP/IP based network protocols for FreeBSD. Thanks - Vishal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Example network protocol implementation
Vishal Patil [EMAIL PROTECTED] wrote: Could someone point me to an example that shows a SIMPLE network protocol implemented over TCP/IP inside the FreeBSD kernel. I think I could look at the NFS client driver but is there an example simpler than that. NFS normally runs over UDP, not TCP. Telnet is one of the simpler TCP-based applications, but it is not done in the kernel (nor are most network apps). Is there some particular reason why you need an example that is implemented inside the kernel, vs in userland? ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Example network protocol implementation
On Saturday 09 December 2006 17:18, Vishal Patil wrote: Could someone point me to an example that shows a SIMPLE network protocol implemented over TCP/IP inside the FreeBSD kernel. I think I could look at the NFS client driver but is there an example simpler than that. Also is there a guide explaining how to go about developing TCP/IP based network protocols for FreeBSD. Try looking at telnet(1) and telnetd(8) source code, also fetch(1) should works too... Thanks - Vishal ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED] Best regards, -- . 0 . | Daniel Molina Wegener . . 0 | dmw at unete dot cl 0 0 0 | FreeBSD User ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Example network protocol implementation
For implementing iSCSI protocol as a kernel driver. On 12/9/06, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Vishal Patil [EMAIL PROTECTED] wrote: Could someone point me to an example that shows a SIMPLE network protocol implemented over TCP/IP inside the FreeBSD kernel. I think I could look at the NFS client driver but is there an example simpler than that. NFS normally runs over UDP, not TCP. Telnet is one of the simpler TCP-based applications, but it is not done in the kernel (nor are most network apps). Is there some particular reason why you need an example that is implemented inside the kernel, vs in userland? ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Example network protocol implementation
In message: [EMAIL PROTECTED] Vishal Patil [EMAIL PROTECTED] writes: : Could someone point me to an example that shows a SIMPLE network protocol : implemented over TCP/IP inside the FreeBSD kernel. I think I could look at : the NFS client driver but is there an example simpler than that. Also is : there a guide explaining how to go about developing TCP/IP based network : protocols for FreeBSD. [ to implement iSCSI in the kernel ] I'm unsure which side you wish to be on. There's accept filters that you can write, but I doubt that's what you want to do. This would be good if you are implementing an iSCSI target on FreeBSD, maybe (then again, maybe not). If you want to be an iSCSI initiator (I think that's the right term), then you'll need to do things similar to what sys/nfsclient/nfs_socket.c does. I could do a quick code walkthrough, but you'd likely be better off studying the nfs code since it will give you a better understanding than I can in a few lines. In addition, because locking has changed over time, the exact version matters. Careful study will show differences in what locks are needed, if any. But in a nutshell, you call socreate to get a socket. You setup the various fields in the socket data structures. You call sosetopt to do the latter. sobind will set this host's endpoint, and soconnect will connect the socket to the remote side. You'll need to setup send and receive buffers and manage them with soreceive and sosend. there's some callbacks that also need to be established as well. And some socket layer locking that may be exposed to your code because there are so few in-kernel protocol implementations that aren't peers to TCP, UDP or IP. I hope this helps. Warner ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
