Date: Wed, 27 Dec 2017 12:37:27 -0500 From: John Lyon <johnllyon@gmail.com> To: Julian Elischer <julian@freebsd.org> Cc: Harry Schmalzbauer <freebsd@omnilan.de>, freebsd-net@freebsd.org, Eugene Grosbein <eugen@grosbein.net> Subject: Re: Need Netgraph Help Message-ID: <CAKfTJoXe%2BZjDEMbF12-JcwBAs0uQoAFYAC3g1A_d0yM8by-z6g@mail.gmail.com> In-Reply-To: <2e0525c8-2251-a5f5-45d1-fe44ebe318f7@freebsd.org> References: <CAKfTJoUMxo7gsio7JJD8Vj_xPgFx5YEBH3_XViFhR0dt59==Dw@mail.gmail.com> <5A3225BF.6020205@omnilan.de> <CAKfTJoX78JhqsvB669Gxsr5UtZkbwuZrnVhOdU2UMacF7FmP1g@mail.gmail.com> <5A32F63E.8010205@grosbein.net> <5A338C5A.20300@omnilan.de> <CAKfTJoW5H82VLyBZ_5_sa9HU7Xbot7imeiP-ogVCNkHGe0_30Q@mail.gmail.com> <2e0525c8-2251-a5f5-45d1-fe44ebe318f7@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Julian, Unfortunately, this issue remains unresolved. I would like to think that this is just a PEBKAC issue, but I have tried every permutation of escape characters in case it's an issue with my syntax and I get the same set of errors. No matter what I do, I can't connect the no match hook of an ETF node to the upper hook of an ng_ether node. Do you have any insights into why this might be occurring? By the way, thanks for reaching out to me! I was going to email you directly after the holidays since your name and email address are at the bottom of the relevant Netgraph man pages. I figured that must mean if you didn't know the answer, no one does. :-) Thanks. -------------------------------- John L. Lyon PGP Key Available At: https://www.dropbox.com/s/skmedtscs0tgex7/02150BFE.asc On Wed, Dec 27, 2017 at 10:32 AM, Julian Elischer <julian@freebsd.org> wrote: > John did you get a resolution to this issue? > > > On 16/12/17 2:59 am, John Lyon wrote: > >> 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 =3D=3D etfp->downstream_hook.hook) { >> error =3D 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 ba= ck >> 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 th= e >> *downstream* hook of the etf node I am creating. As a result, my netgra= ph >> 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 wor= k, >> 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 <freebsd@omnilan.de> >> wrote: >> >> Bez=C3=BCglich Eugene Grosbein's Nachricht vom 14.12.2017 23:07 (localti= me): >>> >>>> 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 >>>>>>> -> matc= h >>>>>>> -> >>>>>>> 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=3D"em1:lower" >>>>>>> ethertype=3D0x888e } >>>>>>> >>>>>>> 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 err= or >>>> 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=3Dmydrain' for the 'msg' comman= d. >>> >>> Do idea about the intention, so for the rest you have to tweak as neede= d. >>> >>> -harry >>> >>> >>> _______________________________________________ >> freebsd-net@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-net >> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >> >> >> >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAKfTJoXe%2BZjDEMbF12-JcwBAs0uQoAFYAC3g1A_d0yM8by-z6g>