open-network-stream-nowait is IPv6 unfriendly

open-network-stream-nowait is IPv6 unfriendly

[Andreas Schwab]

Normally you are supposed to fall back to IPv4 when an IPv6 connection
fails.  But there is no way to do that if you use
open-network-stream-nowait: connect will just return EINPROGRESS, and the
actual connect failure which would otherwise cause make-network-process to
try the next address returned by getaddrinfo is reported as a genuine
error to the process sentinel.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: open-network-stream-nowait is IPv6 unfriendly

[Ken Raeburn]

On Oct 29, 2004, at 09:32, Andreas Schwab wrote:
> Normally you are supposed to fall back to IPv4 when an IPv6 connection
> fails.  But there is no way to do that if you use
> open-network-stream-nowait: connect will just return EINPROGRESS, and 
> the
> actual connect failure which would otherwise cause 
> make-network-process to
> try the next address returned by getaddrinfo is reported as a genuine
> error to the process sentinel.

Sounds like it's unfriendly towards any situation where the destination 
has multiple addresses and one isn't reachable, which can happen in the 
IPv4 world too.  Perhaps the addrinfo list should be preserved in the 
process data until the connection is established, so the handler can 
loop through...

Ken