raw socket, bpf, netgraph, etc
Hello All, Is it possible to get access to link layer (AF_LINK) via raw socket? kind of Linux SOCK_PACKET. It seems to me that it is not. (hope I wrong :) I can access raw IP via socket(AF_INET, SOCK_RAW, IPPROTO_RAW) and event get access to IP header with setsockopt. But not AF_LINK :( On the other hand is bpf. but here is the small problem. i have interface with bpf attached to it. when i write to /dev/bpf i got the same packet back. kind of loop. the only solution is to filter these packets. but there is no way to find out which packet i wrote, and which is received from outside. i was thinking about netgraph. would't it be nice to have netgraph interface in each network driver? Any ideas? Thanks, emax To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: raw socket, bpf, netgraph, etc
On Mon, Feb 14, 2000 at 10:33:47AM -0800, Archie Cobbs wrote: > Yevmenkin, Maksim N, CSCIO writes: > > i was thinking about netgraph. would't it be nice to have netgraph interface > > in each network driver? > > You already do. See ng_ether(8). > > Compile your kernel with options NETGRAPH and then each Ethernet > interface is a netgraph node. Take control of it by connecting > to the "divert" hook. I was trying to figure out if it is possible to route stuff out on a particular interface based on source address using netgraph. At the moment we have an NFS server which pretends to be two machines on the same subnet. To get this to work we're using a small hack in the ipfw divert code. I looked at the netgraph man pages and reckoned it might be possible to do somthing like: fxp0 / ng0 -> bpf \ fxp1 then ifconfig ng0 up with both IP addresses and use the bpf to determine which ethernet card to transmit it on. However, I don't think this will work. First 'cos arp stuff will probably be broken and second because ng0 is a point to point device and won't correctly encapsulate packets for ethernet. Am I correct in thinking that this isn't currently possible with the net graph nodes currently available? David. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: raw socket, bpf, netgraph, etc
David Malone writes: > > Compile your kernel with options NETGRAPH and then each Ethernet > > interface is a netgraph node. Take control of it by connecting > > to the "divert" hook. > > I was trying to figure out if it is possible to route stuff out on > a particular interface based on source address using netgraph. At > the moment we have an NFS server which pretends to be two machines > on the same subnet. To get this to work we're using a small hack > in the ipfw divert code. I looked at the netgraph man pages and > reckoned it might be possible to do somthing like: > >fxp0 > / > ng0 -> bpf > \ >fxp1 > > then ifconfig ng0 up with both IP addresses and use the bpf to > determine which ethernet card to transmit it on. However, I don't > think this will work. First 'cos arp stuff will probably be broken > and second because ng0 is a point to point device and won't correctly > encapsulate packets for ethernet. You're right that that won't work .. you'd be sending raw IP frames on the wire without 14 byte Ethernet headers. > Am I correct in thinking that this isn't currently possible with the > net graph nodes currently available? I think so.. you would have to write a new new node type to add/strip the headers at least. That brings up a good point though.. the ng_iface(8) node type should allow it to configured as a non-point-to-point interface. Ah.. just looked at if_tun.c which does this.. it's trivial. I'll probably check something in after 4.0 then. But even with that change you'd need an add/strip headers thing. In fact, that's another node type I want to write.. just a simple thing that adds & strips headers off packets... or this could be folded into the BPF node type (a BPF program returns a length, after all). -Archie ___ Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: raw socket, bpf, netgraph, etc
Yevmenkin, Maksim N, CSCIO writes: > i was thinking about netgraph. would't it be nice to have netgraph interface > in each network driver? You already do. See ng_ether(8). Compile your kernel with options NETGRAPH and then each Ethernet interface is a netgraph node. Take control of it by connecting to the "divert" hook. -Archie ___ Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
