Harry and Eugene (and others), I appreciate all of your help. It's been really insightful. Although I feel like I'm getting much closer to the solution, I don't think my problem has been diagnosed. I've outlined my thought process below. Can you please tell me if I am misunderstanding something? Admittedly, I am not a kernel developer and my C language skills have atrophied the last few years. However, I've reviewed my script and I looked in the code for ng_etf.c and I don't think I am violating any of the requirements for linking a hook for no match.
As Eugene stated: >>1) referenced "matchook" exists and you should not use "indirect name" here, >>only hook own name, or else you get error ENOENT (No such file or directory); This does not seem to be a problem as the upper and lower hooks for the em1 already exist (I can confirm this). >>2) referenced "matchook" is *not* downstream hook, or else you get error >>EINVAL (Invalid argument); I read the ng_etf.c file in the source tree and found this little snippet: /* and is not the downstream hook */ if (hook == etfp->downstream_hook.hook) { error = EINVAL; break; } This appears to be an error check to make sure you are not creating a cycle in the graph by referencing the ETF node's own downstream hook (i.e. filtering incoming traffic and circularly feeding non-matching frames back into the ETF's own filter). I'm not doing this. I am feeding non-matching packets into the *lower* hook of another ether node and not back into the *downstream* hook of the etf node I am creating. As a result, my netgraph should not be triggering this error condition. >>3) it was not already configured, or else you get error EEXIST (File exists). I am not getting this error, so it appears not to be an issue in my case. What am I missing here? The man page states that "*any other *hook" can be used for the non-matching packets. So the man page says this should work, and there's no explicit error condition that I see (caveat, I have not written in C for at least 10 years - PEBKAC is entirely possible) that would be triggered in the ng_etf code. So what is going wrong? Thanks for all of your help, patience, and understanding. -------------------------------- John L. Lyon PGP Key Available At: https://www.dropbox.com/s/skmedtscs0tgex7/02150BFE.asc On Fri, Dec 15, 2017 at 3:48 AM, Harry Schmalzbauer <free...@omnilan.de> wrote: > Bezüglich Eugene Grosbein's Nachricht vom 14.12.2017 23:07 (localtime): > > 15.12.2017 4:27, John Lyon wrote: > > > >>>> I'm a new Netgraph user, but am having some problems with a simple > >>>> Netgraph > >>>> script I have written. Unfortunately, the error message is cryptic > and I > >>>> can't tell what I am doing wrong since my script closely follows the > >>>> example provided in the ng_etf man page. > >>>> > >>>> For some context, I'm trying to filter EAP traffic coming in on my LAN > >>>> interface. Any ethernet frames that correspond to EAP traffic need > to be > >>>> immediately forwarded from the LAN interface to my WAN interface. All > >>>> other ethernet frames coming in on my LAN interface need to be > handled by > >>>> the kernel's network stack. A (horrid) ASCII art representation of my > >>>> desired netgraph would look like this: > >>>> > >>>> lower -> em0 -> downstream -> ETF -> no match -> upper em0 > >>>> -> match -> > >>>> lower em1 > >>>> > >>>> The script I have written is this: > >>>> > >>>> #! /bin/sh > >>>> ngctl mkpeer em0: etf lower downstream > >>>> ngctl name em0:lower lan_filter > >>>> ngctl connect em0: lan_filter: upper nomatch > >>>> ngctl msg lan_filter: setfilter { matchhook="em1:lower" > >>>> ethertype=0x888e } > >>>> > >>>> Unfortunately, the last line of my script generates the following > error > >>>> message: > >>>> > >>>> ngctl: send msg: Invalid Argument > > > > For "setfilter" command to work, ng_etf requires that: > > > > 1) referenced "matchook" exists and you should not use "indirect name" > here, > > only hook own name, or else you get error ENOENT (No such file or > directory); > > 2) referenced "matchook" is *not* downstream hook, or else you get error > > EINVAL (Invalid argument); > > 3) it was not already configured, or else you get error EEXIST (File > exists). > > Eugene kindly looked into the code and found that the error is due to > wrong matchhook definition. > I've never had any contact with ng_etf yet, but according to the man > page, you need to set the (additional) filter hook by 'nghook -a > lan_filter: mydrain' and use 'matchhook=mydrain' for the 'msg' command. > > Do idea about the intention, so for the rest you have to tweak as needed. > > -harry > > _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"