[pve-devel] [RFC common/manger] use appropriate wildcard address for pveproxy/spiceproxy

[Stoiko Ivanov <s.ivanov@proxmox.com>]

The following patchset tries to address the small regression reported in our
forums [0,1], resulting from defaulting to '::' as listen-address in
pveproxy/spiceproxy.

The issue also affects proxmox-backup-proxy in PBS - and should this approach
be accepted I'll try to port it over to PBS as well.
(ftr: pmgproxy was not affected, since the patch for pmg-api was not applied)

In all cases the issue is only exhibited if ipv6 is diabled via kernel
commandline [2], not via sysctl [3].

* The patchset keeps the fix for pveproxy not starting if the /etc/hosts entry
  is not matching with a configured IP-address (I noticed and was pleasantly
  surprised while testing a v6only host and forgetting to set the entry)

I tested it in the following scenarios:
* ipv6 disabled via kernel commandline (listen on 0.0.0.0)
* ipv6 disabled via sysctl (listen on 0.0.0.0)
* no settings dual-stacked (listen on *)
* no settings v6 only (listen on *)

AFAICT listening on :: as long as possible is the best option, since it
makes the service available on all address-families (doing away, with
having a v4 only /etc/hosts entry, but a DNS AAAA record pointing to
the node for external access).

Took a quick look at how sshd [4,5] handles this (in the assumption that
they have to get it as right as possible), but it listens on multiple
sockets, something which I'd like to avoid for our proxy-daemons.

Sending as RFC, because whenever I come near getaddrinfo/getnameinfo I'm
certain to miss quite a few common cases.

[0] https://forum.proxmox.com/threads/connection-refused-595-nach-update-auf-pve-6-4.88347/#post-387034
[1] https://forum.proxmox.com/threads/ipv6-komplett-deaktivieren.88210/#post-387116
[2] https://www.kernel.org/doc/html/latest/networking/ipv6.html
[3] https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html
[4] https://github.com/openssh/openssh-portable/blob/master/servconf.c
[5] https://github.com/openssh/openssh-portable/blob/master/sshd.c

pve-common:
Stoiko Ivanov (1):
  tools: add get_wildcard_address

 src/PVE/Tools.pm | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

pve-manager:
Stoiko Ivanov (1):
  proxy: fix wildcard address use

 PVE/Service/pveproxy.pm   | 2 +-
 PVE/Service/spiceproxy.pm | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.20.1