Date: Thu, 12 Jan 2012 12:11:04 +0100 From: Michael Tuexen <Michael.Tuexen@lurchi.franken.de> To: smahood@engmail.uwaterloo.ca Cc: freebsd-net@freebsd.org Subject: Re: [PATCH] Have netstat test for sctp kernel support Message-ID: <940650A6-785B-435B-B7C5-7C68925DEC8D@lurchi.franken.de> In-Reply-To: <20111025141741.26891k8ib38ekmkg@www.nexusmail.uwaterloo.ca> References: <20111025141741.26891k8ib38ekmkg@www.nexusmail.uwaterloo.ca>
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On Oct 25, 2011, at 8:17 PM, Sean Mahood wrote:
> Hello,
>=20
> I noticed that when doing a netstat -s (running on a kernel without =
SCTP support compiled in), I get the following message output to stderr:
>=20
> netstat: sysctl: net.inet.sctp.stats: No such file or directory
>=20
> Wondering why it would attempt to fetch SCTP stats when it was =
compiled out of the kernel, I noted that netstat could be compiled =
without SCTP support as well, but that there is no good way to link the =
two compilation conditions, or to have a generic binary that can run =
without error regardless of compiled kernel options.
>=20
> To that end, I added a method to check for environment compatibility =
in netstat. For SCTP specifically, I used the FEATURE macros and added =
SCTP as a FEATURE.
>=20
> Other protocols could also be configured to be checked at runtime if =
desired, though I haven't implemented any others at this time.
Hi Sean,
I agree, the error message should be avoided. There is a similar =
situation for IPv6. When not compiled
into the kernel, netstat should not report an error, even if it is not =
recompiled. The way it is
handled for INET6 is to pay attention to the errno in case =
sysctlbyname() fails. we also have already
one place in the sctp.c code where we do the correct check. I guess it =
was missed in the code
responsable for the above error message.
So what do you think about the attached patch, which resolves the issue =
you reported in a way already
used in netstat and which is portable to other BSD based platform (like =
Mac OS X)?
Thank you very much for reporting the issue.
Best regards
Michael
Index: sctp.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- sctp.c (revision 230008)
+++ sctp.c (working copy)
@@ -611,7 +611,8 @@
memset(&zerostat, 0, len);
if (sysctlbyname("net.inet.sctp.stats", &sctpstat, &len,
zflag ? &zerostat : NULL, zflag ? len : 0) < 0) {
- warn("sysctl: net.inet.sctp.stats");
+ if (errno !=3D ENOENT)
+ warn("sysctl: net.inet.sctp.stats");
return;
}
} else
>=20
> -- Sean
>=20
>=20
>=20
> =
<main.c.diff><netstat.h.diff><sctp.c.diff><sctp_sysctl.c.diff>____________=
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