This patch is a simple implementation for the proposal discussed in
https://mail.openvswitch.org/pipermail/ovs-dev/2017-August/337038.html and
https://mail.openvswitch.org/pipermail/ovs-dev/2017-October/340013.html.
It enables ovs-vswitchd and other utilities to use DNS names when specifying
OpenFlow and OVSDB remotes.
Below are some of the features and limitations of this patch:
- Resolving is asynchornous in daemon context, avoiding blocking main loop;
- Resolving is synchronous in general utility context;
- Both IPv4 and IPv6 are supported;
- The resolving API is thread-safe;
- Depends on the unbound library;
- When multiple ip addresses are returned, only the first one is used;
- /etc/nsswitch.conf isn't respected as unbound library doesn't look at it;
- For async-resolving, caller need to retry later; there is no callback.
Signed-off-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
