Implement pod-network-reload

This adds a new command, 'podman network reload', to reload the
networks of existing containers, forcing recreation of firewall
rules after e.g. `firewall-cmd --reload` wipes them out.

Under the hood, this works by calling CNI to tear down the
existing network, then recreate it using identical settings. We
request that CNI preserve the old IP and MAC address in most
cases (where the container only had 1 IP/MAC), but there will be
some downtime inherent to the teardown/bring-up approach. The
architecture of CNI doesn't really make doing this without
downtime easy (or maybe even possible...).

At present, this only works for root Podman, and only locally.
I don't think there is much of a point to adding remote support
(this is very much a local debugging command), but I think adding
rootless support (to kill/recreate slirp4netns) could be
valuable.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>
Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

4 files changed, 38 insertions, 0 deletions

diff --git a/pkg/domain/entities/engine_container.go b/pkg/domain/entities/engine_container.go
index df7da616a..a4f6c08e9 100644
--- a/pkg/domain/entities/engine_container.go
+++ b/pkg/domain/entities/engine_container.go
@@ -55,6 +55,7 @@ type ContainerEngine interface {
 	NetworkDisconnect(ctx context.Context, networkname string, options NetworkDisconnectOptions) error
 	NetworkInspect(ctx context.Context, namesOrIds []string, options InspectOptions) ([]NetworkInspectReport, []error, error)
 	NetworkList(ctx context.Context, options NetworkListOptions) ([]*NetworkListReport, error)
+	NetworkReload(ctx context.Context, names []string, options NetworkReloadOptions) ([]*NetworkReloadReport, error)
 	NetworkRm(ctx context.Context, namesOrIds []string, options NetworkRmOptions) ([]*NetworkRmReport, error)
 	PlayKube(ctx context.Context, path string, opts PlayKubeOptions) (*PlayKubeReport, error)
 	PodCreate(ctx context.Context, opts PodCreateOptions) (*PodCreateReport, error)
diff --git a/pkg/domain/entities/network.go b/pkg/domain/entities/network.go
index 65a110fd9..b76bfcac7 100644
--- a/pkg/domain/entities/network.go
+++ b/pkg/domain/entities/network.go
@@ -22,6 +22,19 @@ type NetworkListReport struct {
 // NetworkInspectReport describes the results from inspect networks
 type NetworkInspectReport map[string]interface{}
 
+// NetworkReloadOptions describes options for reloading container network
+// configuration.
+type NetworkReloadOptions struct {
+	All    bool
+	Latest bool
+}
+
+// NetworkReloadReport describes the results of reloading a container network.
+type NetworkReloadReport struct {
+	Id  string
+	Err error
+}
+
 // NetworkRmOptions describes options for removing networks
 type NetworkRmOptions struct {
 	Force bool
diff --git a/pkg/domain/infra/abi/network.go b/pkg/domain/infra/abi/network.go
index 6a219edd5..e5ecf5c72 100644
--- a/pkg/domain/infra/abi/network.go
+++ b/pkg/domain/infra/abi/network.go
@@ -60,6 +60,26 @@ func (ic *ContainerEngine) NetworkInspect(ctx context.Context, namesOrIds []stri
 	return rawCNINetworks, errs, nil
 }
 
+func (ic *ContainerEngine) NetworkReload(ctx context.Context, names []string, options entities.NetworkReloadOptions) ([]*entities.NetworkReloadReport, error) {
+	ctrs, err := getContainersByContext(options.All, options.Latest, names, ic.Libpod)
+	if err != nil {
+		return nil, err
+	}
+
+	reports := make([]*entities.NetworkReloadReport, 0, len(ctrs))
+	for _, ctr := range ctrs {
+		report := new(entities.NetworkReloadReport)
+		report.Id = ctr.ID()
+		report.Err = ctr.ReloadNetwork()
+		if options.All && errors.Cause(report.Err) == define.ErrCtrStateInvalid {
+			continue
+		}
+		reports = append(reports, report)
+	}
+
+	return reports, nil
+}
+
 func (ic *ContainerEngine) NetworkRm(ctx context.Context, namesOrIds []string, options entities.NetworkRmOptions) ([]*entities.NetworkRmReport, error) {
 	reports := []*entities.NetworkRmReport{}
 
diff --git a/pkg/domain/infra/tunnel/network.go b/pkg/domain/infra/tunnel/network.go
index 10ae03045..4845980f6 100644
--- a/pkg/domain/infra/tunnel/network.go
+++ b/pkg/domain/infra/tunnel/network.go
@@ -35,6 +35,10 @@ func (ic *ContainerEngine) NetworkInspect(ctx context.Context, namesOrIds []stri
 	return reports, errs, nil
 }
 
+func (ic *ContainerEngine) NetworkReload(ctx context.Context, names []string, options entities.NetworkReloadOptions) ([]*entities.NetworkReloadReport, error) {
+	return nil, errors.New("not implemented")
+}
+
 func (ic *ContainerEngine) NetworkRm(ctx context.Context, namesOrIds []string, options entities.NetworkRmOptions) ([]*entities.NetworkRmReport, error) {
 	reports := make([]*entities.NetworkRmReport, 0, len(namesOrIds))
 	for _, name := range namesOrIds {