Date: Mon, 12 Jun 2006 21:52:37 -0700 From: Sam Leffler <sam@errno.com> To: Xin LI <delphij@delphij.net> Cc: freebsd-arch@freebsd.org Subject: Re: Why do we do if_init for AF_INET even if the interface is running? Message-ID: <448E4495.4030200@errno.com> In-Reply-To: <1150166974.936.6.camel@spirit> References: <1150166974.936.6.camel@spirit>
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Xin LI wrote:
> Hi,
>
> Is there any reason why we do if_init() for AF_INET regardless whether
> the interface is already in IF_DRV_RUNNING? This seems to cause the
> interface to reinitialize its link level state, which causes the network
> to stop for a short while.
>
> The proposed patch is inspired from NetBSD net/if_ethersubr.c,v 1.86
> which says:
>
> "When setting an address on an interface, for address families which
> do not require changing the link-level address, only (*if_init)()
> if the interface is not already RUNNING."
>
> I think we may want this as well.
>
> Comments?
>
> Cheers,
>
>
> ------------------------------------------------------------------------
>
> Index: if_ethersubr.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/net/if_ethersubr.c,v
> retrieving revision 1.215
> diff -u -r1.215 if_ethersubr.c
> --- if_ethersubr.c 3 Mar 2006 17:21:08 -0000 1.215
> +++ if_ethersubr.c 13 Jun 2006 01:55:31 -0000
> @@ -997,7 +997,8 @@
> switch (ifa->ifa_addr->sa_family) {
> #ifdef INET
> case AF_INET:
> - ifp->if_init(ifp->if_softc); /* before arpwhohas */
> + if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
> + ifp->if_init(ifp->if_softc); /* before arpwhohas */
> arp_ifinit(ifp, ifa);
> break;
> #endif
> @@ -1027,7 +1028,8 @@
> }
> #endif
> default:
> - ifp->if_init(ifp->if_softc);
> + if (!(ifp->if_drv_flags & IFF_DRV_RUNNING))
> + ifp->if_init(ifp->if_softc);
> break;
> }
> break;
Try it; you'll find various drivers blow up in their multicast code
because they assume the init method is called. I tried to get this same
change committed last year because it causes wireless drivers to blow
chunks. I finally gave up and stuck a similar change in ieee80211_ioctl.
Sam
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