Add network aliases for containers to DB

This adds the database backend for network aliases. Aliases are
additional names for a container that are used with the CNI
dnsname plugin - the container will be accessible by these names
in addition to its name. Aliases are allowed to change over time
as the container connects to and disconnects from networks.

Aliases are implemented as another bucket in the database to
register all aliases, plus two buckets for each container (one to
hold connected CNI networks, a second to hold its aliases). The
aliases are only unique per-network, to the global and
per-container aliases buckets have a sub-bucket for each CNI
network that has aliases, and the aliases are stored within that
sub-bucket. Aliases are formatted as alias (key) to container ID
(value) in both cases.

Three DB functions are defined for aliases: retrieving current
aliases for a given network, setting aliases for a given network,
and removing all aliases for a given network.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 11 insertions, 0 deletions

diff --git a/libpod/container_validate.go b/libpod/container_validate.go
index b78168cd1..ee3c8583c 100644
--- a/libpod/container_validate.go
+++ b/libpod/container_validate.go
@@ -107,5 +107,16 @@ func (c *Container) validate() error {
 		destinations[vol.Dest] = true
 	}
 
+	// Check that networks and network aliases match up.
+	ctrNets := make(map[string]bool)
+	for _, net := range c.config.Networks {
+		ctrNets[net] = true
+	}
+	for net := range c.config.NetworkAliases {
+		if _, ok := ctrNets[net]; !ok {
+			return errors.Wrapf(define.ErrNoSuchNetwork, "container tried to set network aliases for network %s but is not connected to the network", net)
+		}
+	}
+
 	return nil
 }