Re: (with patch!) Re: ICMP_UNREACH_NEEDFRAG returns iface MTU instead of route?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>>> I suggest we fix it this way for now and count the dancing angels
>>> once we have stopped being stuck with the pins.
>> Why the derision?
> Because it's been two weeks of arguing about _how_ to fix a fairly
> serious bug, while nobody's actually checked anything in to fix it
> even in the interim

What's the urgency about fixing it _now_?  It's sat there for over 12
years - after my previous mail in this thread I found mail I sent to
tech-net back in, if I'm reading things right, 2001-11-04 reporting
what appears to have been the same problem.  And it's been nearly three
years that PR 44508 has sat there.  (I don't know why I didn't commit
anything back in 2001 - I speculate I wasn't running then-current - and
I think I no longer had commit access by 2011-02-03.  In the former I
am at least partially at fault in that I said I'd try a change and if
it worked I'd send-pr it; I find a later mail reporting that the change
worked, but I see no evidence I created a PR for it until 2011.)

>> [I]f you really think NetBSD would be better off paying attention to
>> route MTUs only sometimes, go for it.
> I think that if this discussion illustrates anything, it's that the
> notion of a "route MTU" is incoherent --

I don't see it as incoherent, just not used everywhere it needs to be.

> a back-formed conceptual rationale for the expedient hack of storing
> path MTUs in the routing table, which we're now paying for.

If so, it's a remarkably useful expedient hack.  I've found lots of
cases where route MTUs are useful.  And one of the indications that a
thing is a right thing is when it finds uses not anticipated by its
creators.

> I *do* object to the bickering over what seems to me to be the
> consequent neologism "route MTU" preventing us from quickly applying
> an obvious fix to solve these old, very real, problems for users
> caused by the original implementation of path MTU.

Well, sure, apply a fix.  I'd just rather it be the one that results in
a more useful system.  But, of course, I'm not the one doing the work,
I won't be running the result, and even if I were I'm entirely
competent to replace it with the more useful fix locally anyway.  I
just prefer to see things done right.

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