This patch enables OVS on windows to read system nameserver configuration.
In addition, a new environment variable OVS_RESOLV_CONF is introduced.
If set, it can be used as DNS server configuration file. This variable
is supposed to be used for sandboxing other things. It is documented
accordingly.
Suggested-by: Ben Pfaff <blp@ovn.org>
Suggested-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
DNS resolution should fail if no DNS servers are available. This
patch fixes it.
Suggested-by: Ben Pfaff <blp@ovn.org>
Suggested-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
The unbound library complains if we ask it to read /etc/resolv.conf but
that file doesn't exist. It's better to just skip reading it in that case.
Reported-by: Flavio Leitner <fbl@sysclose.org>
Reporetd-at: https://mail.openvswitch.org/pipermail/ovs-dev/2018-August/350751.html
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Flavio Leitner <fbl@sysclose.org>
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>
