Vendor CNI plugins firewall code

The upstream CNI project has a PR open for adding iptables and
firewalld support, but this has been stalled for the better part
of a year upstream.

On advice of several maintainers, we are vendoring this code into
libpod, to perform the relevant firewall configuration ourselves.

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #1431
Approved by: baude

1 files changed, 47 insertions, 0 deletions

diff --git a/pkg/firewall/firewall_linux.go b/pkg/firewall/firewall_linux.go
new file mode 100644
index 000000000..4ac45427b
--- /dev/null
+++ b/pkg/firewall/firewall_linux.go
@@ -0,0 +1,47 @@
+// +build linux
+
+// Copyright 2016 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package firewall
+
+import (
+	"fmt"
+)
+
+// GetBackend retrieves a firewall backend for adding or removing firewall rules
+// on the system.
+// Valid backend names are firewalld, iptables, and none.
+// If the empty string is given, a firewalld backend will be returned if
+// firewalld is running, and an iptables backend will be returned otherwise.
+func GetBackend(backend string) (FirewallBackend, error) {
+	switch backend {
+	case "firewalld":
+		return newFirewalldBackend()
+	case "iptables":
+		return newIptablesBackend()
+	case "none":
+		return newNoneBackend()
+	case "":
+		// Default to firewalld if it's running
+		if isFirewalldRunning() {
+			return newFirewalldBackend()
+		}
+
+		// Otherwise iptables
+		return newIptablesBackend()
+	default:
+		return nil, fmt.Errorf("unrecognized firewall backend %q", backend)
+	}
+}