Hi, On Sat, Jan 11, 2014 at 11:01:58AM +0100, Tore Anderson wrote: > > I *thought* that both proto udp and proto udp6 would create an IPv6 socket > > bound to :: with IPV6_V6ONLY set to 0 (= accepting IPv4 and IPv6 packets > > to any address). Only "proto udp4" should listen to 0.0.0.0. > > This is not how git master behaves for me. "proto udp" and "proto udp4" > both yield an IPv4-only socket (AF_INET):
Mmmh. Right you are, at least on *Linux*...
"proto upd6" gives an udp6/TYPE=IPv6 socket, while "proto udp" gives
an udp/TYPE=IPv4 socket, on my Gentoo system (and this is not an artifact
from netstat or lsof, but it really only listens on 0.0.0.0)...
Sat Jan 11 12:27:35 2014 us=883703 proto = udp
Sat Jan 11 12:27:35 2014 us=883794 local = '[UNDEF]'
Sat Jan 11 12:27:35 2014 us=883885 local_port = '61194'
Sat Jan 11 12:27:35 2014 us=912736 UDP link local (bound):
[AF_INET][undef]:61194
When I tested that, I used a FreeBSD system, which behaves differently -
there, "proto udp" gives the same result as "proto udp6", and you need to do
"proto udp4" to get an IPv4-only socket...
Sat Jan 11 12:11:44 2014 us=286820 proto = udp
Sat Jan 11 12:11:44 2014 us=286849 local = '[UNDEF]'
Sat Jan 11 12:11:44 2014 us=286877 local_port = '51194'
Sat Jan 11 12:11:44 2014 us=383743 UDP link local (bound):
[AF_INET6][undef]:51194
$ netstat -an |grep 1194
udp46 0 0 *.51194 *.*
I do think I know where the problem is coming from (or, more precise, Arne
mentioned this a while ago already) - Arne's new code uses getaddrinfo()
with AI_PASSIVE to get "something suitable for listening on", and Linux'
getaddrinfo() seems to return INADDR_ANY before IN6ADDR_ANY, which is
arguably a pretty stupid thing to do... and yes, I think that we should
workaround this.
> I can submit a separate bug
> report about this if you wish. That said, I would be perfectly happy to
> simply use "proto udp6" instead, IFF "multihome" had worked correctly.
Our documentation says that "proto udp" or "proto tcp[-server]" is "use
dual-stack", so it should better do that, correctly on all platforms.
Bug opened, #360, and assigned to Arne. Thanks for telling us.
gert
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