Date: Sat, 01 Nov 2008 19:20:52 -0400 From: Bryant Eadon <bryant.eadon@gmail.com> To: Joe Pellegrino <jdp@elvis.rowan.edu> Cc: freebsd-questions@freebsd.org Subject: Re: A netgraph question. Message-ID: <490CE454.2020800@gmail.com> In-Reply-To: <Pine.GSO.4.64.0811011624310.1498@elvis.rowan.edu> References: <Pine.GSO.4.64.0811011523510.1498@elvis.rowan.edu> <Pine.GSO.4.64.0811011624310.1498@elvis.rowan.edu>
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Joe Pellegrino wrote: OK so here it goes. I actually have two seperate questions involving > netgraph, I am new to this subject so please bare with me. If there is a > better way to achieve these goals too, please suggest them but I think > netgraph is the way to go. > > The first part involves allowing a userland program to communicate with > a kernel module, similar to how netlink works in Linux. The second part > involves intercepting network packets and possibly manipulating them > before they are allowed to proceed, similar to how netfilter works. I > believe I can do both of these with the netgraph (ng_socket and possibly > ng_ether). I haven't looked closely at ng_ether yet so I'll focus on > ng_socket. > > I have been able to create a ng_socket (Control and Data) using the > socket call as described in "All About NetGraphs" and the man page. I've > also been able to 'name' the node using bind. I was able to verify this > using ngctl. I know (from the man page) I should eventually be able to > send/receive using the sendto/recvfrom functions once the connection is > established. But beyond this I don't know how to proceed. So the > question is what are the next steps. For example: > > Although I see a named netgraph node there are no hooks. ng_socket says > it supports an arbitrary number of hooks so how do I create the hooks? > Then of course how do I connect them. > > Of course I realize that I proabably need to create a node on the kernel > side so which type of netgraph node would be suggested? How is it > created and then hooked to the ng_socket? > > Again I am looking to allow some IPC between a userland program and a > kernel module similar to the Linux netlink. I've been through most man > pages and can't seem to find a lot of good documentation or example code > so I am hoping to get some pointers here. BTW If this is the wrong list > please directly to the right place to ask. Thanks in advance. > > ---jdp > Have you looked into how "systat -ifstat" works ?
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