Date: Thu, 04 Apr 2002 18:17:46 +0100 From: Brian Somers <brian@freebsd-services.com> To: Doug Ambrisko <ambrisko@ambrisko.com> Cc: "M. Warner Losh" <imp@village.org>, j@uriah.heep.sax.de, alan@clegg.com, luigi@FreeBSD.org, nsayer@FreeBSD.org, ryand-bsd@zenspider.com, Brian Somers <brian@freebsd-services.com>, freebsd-arch@FreeBSD.org, freebsd-net@FreeBSD.org Subject: Re: Your change to in.c to limit duplicate networks is causing trouble Message-ID: <200204041717.g34HHkq7037326@hak.lan.Awfulhak.org> In-Reply-To: Message from Doug Ambrisko <ambrisko@ambrisko.com> of "Mon, 25 Mar 2002 11:34:50 PST." <200203251934.g2PJYoY68469@ambrisko.com>
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I've crossposted to -net and -arch as this could probably do with a
review from a larger audience....
> Brian Somers writes:
> | > In message: <20020325172024.B60771@uriah.heep.sax.de>
> | > Joerg Wunsch <j@uriah.heep.sax.de> writes:
> | > : As Alan Clegg wrote:
> | > :
> | > : > Is there any motion to pull this back?
> | > :
> | > : There was only consensus to special-case the BOOTP case.
> | > :
> | > : As i understand it, the change itself was more than desirable for
> | > : PPP connections (so no surprise it was Brian who committed it).
> | >
> | > dhclient is still broken, however. The 0.0.0.0 should be the special
> | > case, not bootp.
> |
> | Yes, I agree.
> |
> | The question is.... should interface address assignments with
> | destinations of 0.0.0.0 have host routes created in the first place ?
> |
> | I'd tend to think not.
> |
> | Doing this will make things consistent, but maybe at the expense of
> | breaking something else - under ``usual'' circumstances. I'm
> | thinking along the lines of some program that may configure a
> | destination address of 0.0.0.0 and then expect to be able to do stuff
> | with the routing table - such as adding a route via 0.0.0.0 or calling
> | sendto() or connect() with 0.0.0.0 as the destination.
> |
> | I'm guessing that dhclient will continue to work without a host route
> | as it writes raw IP packets, and I haven't heard of any problems with
> | running multiple dhclients using the old in.c code where second and
> | subsequent SIOCAIADDRs with a 0.0.0.0 destination had no host route.
> | I haven't tested it yet though.
> |
> | If nobody objects, I'll tweak things so that destinations of 0.0.0.0
> | don't add host routes and see if it breaks anything I know of. I'll
> | post patches to -arch and cc -net when I get something working.
>
> Sounds reasonable. I can test it when you have something since I'm hitting
> this on a few machines around here.
>
> Doug A.
The attached patches seem to make things work for BOOTP with multiple
interfaces and for ppp expecting failures for duplicate destination
address assignments.
The code now avoids adding a host route if the interface address is
0.0.0.0, and always treats a failure to add a host route as fatal
(previously, it masked EEXIST for some reason - I guessed because it
was trying to handle address re-assignment, but that works ok with
this patch).
If people could get some time to review it, it'd be appreciated.
Cheers.
--
Brian <brian@freebsd-services.com> <brian@Awfulhak.org>
http://www.freebsd-services.com/ <brian@[uk.]FreeBSD.org>
Don't _EVER_ lose your sense of humour ! <brian@[uk.]OpenBSD.org>
Index: netinet/in.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/in.c,v
retrieving revision 1.63
diff -u -r1.63 in.c
--- netinet/in.c 1 Apr 2002 21:31:06 -0000 1.63
+++ netinet/in.c 4 Apr 2002 16:52:59 -0000
@@ -661,7 +661,7 @@
{
register u_long i = ntohl(sin->sin_addr.s_addr);
struct sockaddr_in oldaddr;
- int s = splimp(), flags = RTF_UP, error;
+ int s = splimp(), flags = RTF_UP, error = 0;
oldaddr = ia->ia_addr;
ia->ia_addr = *sin;
@@ -723,17 +723,21 @@
return (0);
flags |= RTF_HOST;
}
- if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0)
- ia->ia_flags |= IFA_ROUTE;
- if (error != 0 && ia->ia_dstaddr.sin_family == AF_INET) {
- ia->ia_addr = oldaddr;
- return (error);
+ /*
+ * Don't add routing table entries for interface address entries
+ * of 0.0.0.0. This makes it possible to assign several such address
+ * pairs with consistent results (no host route) and is required by
+ * BOOTP.
+ */
+ if (ia->ia_addr.sin_addr.s_addr != INADDR_ANY) {
+ if ((error = rtinit(&ia->ia_ifa, (int)RTM_ADD, flags)) != 0) {
+ ia->ia_addr = oldaddr;
+ return (error);
+ }
+ ia->ia_flags |= IFA_ROUTE;
}
- /* XXX check if the subnet route points to the same interface */
- if (error == EEXIST)
- error = 0;
/*
* If the interface supports multicast, join the "all hosts"
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