Date: Sat, 24 Feb 2007 12:47:47 +0100 From: "Jouke Witteveen" <j.witteveen@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: [PATCH] Re: ioctl: SIOCADDMULTI (howto?) Message-ID: <3993a4980702240347o2ee0388bx42e29854928cadfd@mail.gmail.com> In-Reply-To: <45D748C5.6040904@FreeBSD.org> References: <3993a4980702051233u10c30575kd1f6d27fcd600110@mail.gmail.com> <45C7A1F9.20306@FreeBSD.org> <3993a4980702170546t7f9384eaq358986a4cc734582@mail.gmail.com> <45D748C5.6040904@FreeBSD.org>
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[-- Attachment #1 --]
On 2/17/07, Bruce M. Simpson <bms@freebsd.org> wrote:
> Jouke Witteveen wrote:
> >
> > So my apologies for suggesting it doesn't work at all; it seems that
> > the application I'm trying to get to work (wpa_supplicant for wired
> > interfaces) just doesn't _send_ its packets the right way.
> That's a big relief! I added an item to the Wiki for someone to write a
> regression test.
> >
> > Things aren't perfect though. In if.c the if_findmulti function is
> > broken (always returns NULL). I presume just comparing the
> > *LLADDR((sockaddr *)sa) data on both sockets is a better check, though
> > my knowledge on these things is limited.
> I think I see a possible problem, though the code looks as though it is
> behaving as expected.
> I am looking at RELENG_6 if.c. I think sa_equal() may be to blame.
>
> sa_equal() performs a binary comparison on all of sa_data up to sa_len.
> Looking at struct sockaddr_dl, this might not be the right thing at all
> in that situation... though I need another pair of eyes to look. Can
> anyone shed light on this? An AF_INET and AF_INET6 address can be
> completely specified and compared with sa_equal(). An AF_LINK address
> looks as though sa_equal() may return irrational results.
> >
> > As for netstat, I do not really know what is keeping it from showing
> > the Multicast addresses. Again: my knowledge on this matter is
> > limited. All I can think of is that getifmaddrs is forgetting
> > something (perhaps the lack of a group membership). Maybe you can take
> > a look at it (I believe you wrote it).
>
> I wrote the libc getifmaddrs() function and integrated it into netstat
> -g; Harti Brandt wrote the NET_RT_IFMALIST support. getifmaddrs()
> *should* return sockaddr_dl as well as sockaddr_in and all the others.
>
> netstat skips over AF_LINK addresses. Try this patch to reveal them. It
> doesn't seem to show the IPv4 link layer memberships underneath, which
> is interesting...
> >
> > As I am still learning how best to contribute to a project as big as
> > FreeBSD and I do not think I am skilled enough yet in C I refrain from
> > writing a patch. I am eager to see one though, be it only out of
> > curiosity to know what would be considered a proper fix.
> Give it a try anyway! I like to think we have strong healthy egos round
> here.
>
> Regards,
> BMS
>
>
Thanks for that enormous stimulation; it really gave me some
confidence. I have (before I saw your ethermcast.diff patch) been
trying some things too and found that the patch attached did the job
for me. As for now I haven't found any glitches yet as a result of
this change. I notice however that you have probably foreseen quite
some situations with your patch, since it looks far more complex than
mine. However I'm pleased to see I managed to get something done
myself.
As for the netstat patch: it works like a shine! Very nicely done (ie: thanks).
I will now try to make the wired driver of wpa_supplicant work in
FreeBSD (it still isn't able to send/receive packages properly), as
that is what started this whole bug-hunt of mine.
Thanks again for your help and motivation.
Regards,
- Jouke
[-- Attachment #2 --]
--- if.c.orig Wed Feb 15 04:37:15 2006
+++ if.c Thu Feb 22 09:12:11 2007
@@ -1838,11 +1838,17 @@
if_findmulti(struct ifnet *ifp, struct sockaddr *sa)
{
struct ifmultiaddr *ifma;
+ caddr_t data = LLADDR((struct sockaddr_dl *)sa);
IF_ADDR_LOCK_ASSERT(ifp);
TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
- if (sa_equal(ifma->ifma_addr, sa))
+ /*
+ * In multicasting we are only interested in the address value
+ * obtained with LLADDR().
+ */
+ if (bcmp(LLADDR((struct sockaddr_dl *)ifma->ifma_addr), data,
+ ETHER_ADDR_LEN) == 0)
break;
}
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