Date: Thu, 01 Jan 1998 18:19:50 +0000 From: Brian Somers <brian@awfulhak.org> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: Brian Somers <brian@awfulhak.org>, John-Mark Gurney <gurney_j@efn.org>, freebsd-bugs@hub.freebsd.org, freebsd-hackers@freebsd.org Subject: Re: kern/5404: slXX slip (tun & ppp) interfaces always point to point Message-ID: <199801011819.SAA19774@awfulhak.demon.co.uk> In-Reply-To: Your message of "Thu, 01 Jan 1998 18:50:07 %2B0100." <19980101185007.59283@uriah.heep.sax.de>
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> As Brian Somers wrote: > > > I intended to remove the possibility of netmasks and broadcast > > addresses for pointopoint links, but retrospectively, this will break > > the ability to attach to a peer that proxy arps for you (well, it's > > already broken). > > Why? Proxyarping is done on the Ethernet interface, and this one > still has a netmask. I mean in the sense that the client cannot broadcast on the network at the other end of the pointopoint link, or can it ? I guess you could set up a static route for the broadcast address. That should work. I haven't tried. > > I would suggest (and I'm willing to do it) adding the ability to use > > SIOCSIFPOINTOPOINT and SIOCGIFPOINTOPOINT on sl* ppp* and tun*. The > > default is that these interfaces are pointopoint, but you can change > > that by issuing the `S' ioctl. > > Nope, you can't. `p2p' is an unchangeable attribute of an interface, > see IFF_CANTCHANGE in /sys/net/if.h. Perhaps IFF_POINTOPOINT should be settable while the interface is down only. In the `tun' case (I'm not sure about pppX & slX) it could be done at the ioctl(TUNSIFINFO) stage - the `dummy' part of the struct tuninfo could be changed to specify the interface flags. But this would break existing code that never initialises `dummy' to zero (which, it really should, although ppp doesn't :-(). OpenBSD already has this requirement. The `dummy' part is replaced by `flags' and those flags must specify IFF_POINTOPOINT if you want that. I'm not actually sure what happens there if you don't specify IFF_POINTOPOINT. > -- > cheers, J"org > > joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE > Never trust an operating system you don't have sources for. ;-) -- Brian <brian@Awfulhak.org>, <brian@FreeBSD.org>, <brian@OpenBSD.org> <http://www.Awfulhak.org>; Don't _EVER_ lose your sense of humour....
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