Date: Tue, 3 Feb 2004 08:04:40 -0800 From: Brooks Davis <brooks@one-eyed-alien.net> To: Andre Oppermann <andre@freebsd.org> Cc: cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/netinet ip_icmp.c Message-ID: <20040203160440.GB27244@Odin.AC.HMC.Edu> In-Reply-To: <401F5531.35474513@freebsd.org> References: <200402022253.i12MrGkO091411@repoman.freebsd.org> <20040202232614.GA24019@Odin.AC.HMC.Edu> <401EE109.D45B606@freebsd.org> <20040203000622.GA19568@Odin.AC.HMC.Edu> <401F5531.35474513@freebsd.org>
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--b5gNqxB1S1yM7hjW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 03, 2004 at 09:00:49AM +0100, Andre Oppermann wrote: > Brooks Davis wrote: > >=20 > > On Tue, Feb 03, 2004 at 12:45:13AM +0100, Andre Oppermann wrote: > > > Brooks Davis wrote: > > > > > > > > On Mon, Feb 02, 2004 at 02:53:16PM -0800, Andre Oppermann wrote: > > > > > andre 2004/02/02 14:53:16 PST > > > > > > > > > > FreeBSD src repository > > > > > > > > > > Modified files: > > > > > sys/netinet ip_icmp.c > > > > > Log: > > > > > Add sysctl net.inet.icmp.reply_src to specify the interface name > > > > > used for the ICMP reply source in reponse to packets which are = not > > > > > directly addressed to us. By default continue with with normal > > > > > source selection. > > > > > > > > Please consider storing the interface index rather then the name. = It is > > > > much cheaper to go from index to ifp then name to ifp and the index= will > > > > be invariant as long as the interface exists. Sometime in the next= week > > > > the name will no longer be invariant. > > > > > > I considered storing the ifp but the moment a stored ipf disappears > > > you get an instant panic. There is no way to verify if the interface > > > pointer is still valid. And with interface cloning I considered the > > > panic risk too high. The only other way would be to check the ifp ev= ery > > > time a interface is manipulated and to purge the ifp if its interface= is > > > gone. I thought that was too intrusive. > >=20 > > I'm not sugguesting caching the ifp. I'm suggesting storing the value > > of ifp->if_index. You then use ifnet_byindex to get then the ifp when > > needed. You have to check that it isn't NULL, but you should to be > > doing that for the ifunit() call as well since it will return NULL and > > cause a panic if the admin makes a typo. >=20 > Using the ifindex is a good way out. The check for NULL is already > done, so a wrong interface name wont panic the box. Ah, the check is done, but the check was done without explicit compatison to NULL so I spaced and missed it. That's probalby worth changing when you do the rest since style(9) suggests not trating pointers and bools. > > As Juli commented, a SYSCTL_PROC to allow the administrator to get/set > > the interface by name is probably the right approach. >=20 > I'll write a modification to use the ifindex. Since the ifname can > change now it will have to resolve the index to name when someone is > looking at the sysctl. Thanks! Thanks. -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --b5gNqxB1S1yM7hjW Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFAH8aUXY6L6fI4GtQRAjOzAJ9WPu40b5OowV6x4TW/QHXvIVcuEgCff2xq 2DtpuzZGFkHS4YmsjpoWZf8= =UlFu -----END PGP SIGNATURE----- --b5gNqxB1S1yM7hjW--
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