Date: Wed, 25 Feb 2004 17:13:26 +0300 From: Gleb Smirnoff <glebius@cell.sick.ru> To: Andre Oppermann <andre@freebsd.org>, freebsd-net@freebsd.org Subject: Re: rtalloc()/rtfree() problems on CURRENT Message-ID: <20040225141326.GA86194@cell.sick.ru> In-Reply-To: <20040224130408.GA78658@cell.sick.ru> References: <20040224080353.GA76272@cell.sick.ru> <403B2423.DABF2E48@freebsd.org> <20040224102113.GB77406@cell.sick.ru> <403B4182.F6BD7101@freebsd.org> <20040224123427.GA78495@cell.sick.ru> <403B47D4.6F783F4F@freebsd.org> <20040224130408.GA78658@cell.sick.ru>
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On Tue, Feb 24, 2004 at 04:04:08PM +0300, Gleb Smirnoff wrote:
T> A> Ah, sorry, forgot that in my last email. The only thing is to use RTFREE().
T> A> At first I thought your reassigning of rt is a problem, but you free the
T> A> correct ro.ro_rt later.
T>
T> Thank you! I'll try everything you suggested today night.
Thanks again. Using RTFREE() fixed the problem. It works OK both
on STABLE and CURRENT.
If you don't mind I have one more question, though. Looking through kernel
code, seeking for examples, I have found following in in_gif.c:
rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
if (!rt || rt->rt_ifp != ifp) {
#if 0
log(LOG_WARNING, "%s: packet from 0x%x dropped "
"due to ingress filter\n", if_name(&sc->gif_if),
(u_int32_t)ntohl(sin.sin_addr.s_addr));
#endif
if (rt)
rtfree(rt);
return 0;
}
rtfree(rt);
And it doesn't crash. Looking through the code I understood that
in case of rtalloc()/rtfree() or rtalloc_ign()/rtfree() macro RT_UNLOCK
is called twice, and this leads to panic. But in case of rtalloc1()/rtfree()
everything is OK, since RT_UNLOCK is called once.
So, the question is: if I need some readonly access to routing table can
I use rtalloc1()/rtfree() or not? Will RTFREE be mandatory in future?
This will save some small amount of CPU time, but this code is executed
really often.
--
Totus tuus, Glebius.
GLEBIUS-RIPN GLEB-RIPE
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