Date: Tue, 19 Apr 2005 21:14:06 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Sam Leffler <sam@errno.com> Cc: net@FreeBSD.org Subject: Re: if_link_state_change() patch for review Message-ID: <20050419171406.GA378@cell.sick.ru> In-Reply-To: <42652357.8020604@errno.com> References: <20050419064747.GC734@cell.sick.ru> <4264D430.D39B81D0@freebsd.org> <20050419120324.GA5862@cell.sick.ru> <4264F4BC.4F3B57AE@freebsd.org> <20050419121141.GB5862@cell.sick.ru> <4264F7D4.F5A9775F@freebsd.org> <42652357.8020604@errno.com>
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On Tue, Apr 19, 2005 at 08:27:19AM -0700, Sam Leffler wrote: S> >change message will report either all state changes or those where at S> >the time of reporting the state changed relative to the last report. S> >The same assumption is true for the OpenIGPd we are working on at the S> >moment. S> S> It is possible with the change to defer the messages to have multiple S> changes coalesced. If an app is written to assume it receives notice of S> every change and it uses this to track internal state then it can get S> confused. The issue was whether or not to communicate any coalescing to S> applications so they can recognize that it's happened. In lieu of doing S> that I asked for a console printf so we could see if it ever happened in S> practice. Yes, all the time we are speaking about a theoretical issue. Let's see whether it can happen or not. I decided to go ahead with this change. S> >From an (routing) application point of view only effective state changes S> >are interesting and only those should be provided. S> > S> S> If an inteface does down, moves network, then comes back up and you only S> get the up event then you will likely do the wrong thing unless you have S> some other way of identifying what happened. I'm not convinced (yet) S> this cannot happen so am being cautious. In this case you will receive additional messages, not only RTM_IFINFO. Move network will also generate RTM_NEWADDR and RTM_DELADDR -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE
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