Re: sockets affected by IPsec always block (2.6.23)

[David Miller <davem@davemloft.net>]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 5 Dec 2007 18:16:07 +1100

> Right.  This is definitely bad for protocols without a retransmission
> mechanism.
> 
> However, is the 0 setting ever useful for TCP and in particular, TCP's
> connect(2) call? Perhaps we can just make that one always drop.

TCP has some built-in assumptions about characteristics of
interent links and what constitutes a timeout which is "too long"
and should thus result in a full connection failure.

IPSEC changes this because of IPSEC route resolution via
ISAKMP.

With this in mind I can definitely see people preferring
the "block until IPSEC resolves" behavior, especially for
something like, say, periodic remote backups and stuff like
that where you really want the thing to just sit and wait
for the connect() to succeed instead of failing.