connect(2) behavior with unreacheable hosts

[Mike Silbersack]

On Sat, 12 Apr 2003, M. Warner Losh wrote:

> In message: <20030413030500.GA64896 at pit.databus.com>
>             Barney Wolff <barney at pit.databus.com> writes:
> : On Sat, Apr 12, 2003 at 08:49:12PM -0600, M. Warner Losh wrote:
> : > In message: <109.225ca595.2bc723f2 at aol.com>
> : >             BelletJr at aol.com writes:
> : > : Why does not connect(2) return any error when trying to connect to a host
> : > : unreachable because of an infinite loop in the routes? No time-out occurs and
> : > : the value 0 is returned by connect(2).
> : >
> : > Hmmmmm, you are correct.  I was sure that you were nuts, but on
> : > -current the following program returns no error at all...  Telnet
> : > shows the same behavior.  This is clearly wrong.
> :
> : It's not just current; stable behaves exactly the same.  The problem is
> : that the icmp time-exceeded packet gets translated into an error code
> : of 0, which confuses things.  I've filed a PR with a suggested fix:
> : http://www.freebsd.org/cgi/query-pr.cgi?pr=50839
>
> Ah.  I see.  I wonder if any of the net folks can review this...
>
> Warner

EPLATEFULL, but it sounds correct...

Barney, have you tried doing some sort of test where sendmail or ftpd
tries making a connection to a TTL exceeded IP?  I'm curious if they
handle the situation gracefully or not.  (If they don't, then maybe this
is serious enough to require security branch merges.)

Mike "Silby" Silbersack