pkg/specgen: parse default network mode on server

When podman-remote is used we should not resolve the default network
mode on the client. Defaults should be set on the server. In this case
this is important because we have different defaults for root/rootless.
So when the client is rootless and the server is root we must pick the
root default.

Note that this already worked when --network was set since we did not
parsed the flag in this case. To reproduce you need --network=default.

Also removed a unused function.

[NO NEW TESTS NEEDED] I tested it manually but I am not sure how I can
hook a test like this up in CI. The client would need to run as rootless
and the server as root or the other way around.

Fixes #14368

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

2 files changed, 12 insertions, 9 deletions

diff --git a/pkg/specgen/generate/namespaces.go b/pkg/specgen/generate/namespaces.go
index 37d561ec2..4dd6b3eaf 100644
--- a/pkg/specgen/generate/namespaces.go
+++ b/pkg/specgen/generate/namespaces.go
@@ -236,10 +236,12 @@ func namespaceOptions(s *specgen.SpecGenerator, rt *libpod.Runtime, pod *libpod.
 		toReturn = append(toReturn, libpod.WithCgroupsMode(s.CgroupsMode))
 	}
 
-	// Net
-	// TODO validate CNINetworks, StaticIP, StaticIPv6 are only set if we
-	// are in bridge mode.
 	postConfigureNetNS := !s.UserNS.IsHost()
+	// when we are rootless we default to slirp4netns
+	if rootless.IsRootless() && (s.NetNS.IsPrivate() || s.NetNS.IsDefault()) {
+		s.NetNS.NSMode = specgen.Slirp
+	}
+
 	switch s.NetNS.NSMode {
 	case specgen.FromPod:
 		if pod == nil || infraCtr == nil {
@@ -262,9 +264,7 @@ func namespaceOptions(s *specgen.SpecGenerator, rt *libpod.Runtime, pod *libpod.
 			val = fmt.Sprintf("slirp4netns:%s", s.NetNS.Value)
 		}
 		toReturn = append(toReturn, libpod.WithNetNS(portMappings, expose, postConfigureNetNS, val, nil))
-	case specgen.Private:
-		fallthrough
-	case specgen.Bridge:
+	case specgen.Bridge, specgen.Private, specgen.Default:
 		portMappings, expose, err := createPortMappings(s, imageData)
 		if err != nil {
 			return nil, err
diff --git a/pkg/specgen/generate/pod_create.go b/pkg/specgen/generate/pod_create.go
index 83730e657..fdc98ccc2 100644
--- a/pkg/specgen/generate/pod_create.go
+++ b/pkg/specgen/generate/pod_create.go
@@ -225,6 +225,9 @@ func MapSpec(p *specgen.PodSpecGenerator) (*specgen.SpecGenerator, error) {
 	case specgen.Bridge:
 		p.InfraContainerSpec.NetNS.NSMode = specgen.Bridge
 		logrus.Debugf("Pod using bridge network mode")
+	case specgen.Private:
+		p.InfraContainerSpec.NetNS.NSMode = specgen.Private
+		logrus.Debugf("Pod will use default network mode")
 	case specgen.Host:
 		logrus.Debugf("Pod will use host networking")
 		if len(p.InfraContainerSpec.PortMappings) > 0 ||
@@ -235,15 +238,15 @@ func MapSpec(p *specgen.PodSpecGenerator) (*specgen.SpecGenerator, error) {
 		p.InfraContainerSpec.NetNS.NSMode = specgen.Host
 	case specgen.Slirp:
 		logrus.Debugf("Pod will use slirp4netns")
-		if p.InfraContainerSpec.NetNS.NSMode != "host" {
+		if p.InfraContainerSpec.NetNS.NSMode != specgen.Host {
 			p.InfraContainerSpec.NetworkOptions = p.NetworkOptions
-			p.InfraContainerSpec.NetNS.NSMode = specgen.NamespaceMode("slirp4netns")
+			p.InfraContainerSpec.NetNS.NSMode = specgen.Slirp
 		}
 	case specgen.NoNetwork:
 		logrus.Debugf("Pod will not use networking")
 		if len(p.InfraContainerSpec.PortMappings) > 0 ||
 			len(p.InfraContainerSpec.Networks) > 0 ||
-			p.InfraContainerSpec.NetNS.NSMode == "host" {
+			p.InfraContainerSpec.NetNS.NSMode == specgen.Host {
 			return nil, errors.Wrapf(define.ErrInvalidArg, "cannot disable pod network if network-related configuration is specified")
 		}
 		p.InfraContainerSpec.NetNS.NSMode = specgen.NoNetwork