lang: core: net: Add a way to get the machine mac addresses

lang/core/net/macs.go

@@ -0,0 +1,80 @@
+// Mgmt
+// Copyright (C) 2013-2024+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+// Additional permission under GNU GPL version 3 section 7
+//
+// If you modify this program, or any covered work, by linking or combining it
+// with embedded mcl code and modules (and that the embedded mcl code and
+// modules which link with this program, contain a copy of their source code in
+// the authoritative form) containing parts covered by the terms of any other
+// license, the licensors of this program grant you additional permission to
+// convey the resulting work. Furthermore, the licensors of this program grant
+// the original author, James Shubin, additional permission to update this
+// additional permission if he deems it necessary to achieve the goals of this
+// additional permission.
+
+package corenet
+
+import (
+	"context"
+	"net"
+
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
+	"github.com/purpleidea/mgmt/lang/types"
+)
+
+func init() {
+	simple.ModuleRegister(ModuleName, "macs", &simple.Scaffold{
+		T: types.NewType("func() []str"),
+		F: Macs,
+	})
+}
+
+// Macs returns the list of mac addresses that are seen on the machine.
+//
+// XXX: These should produce new values if the list of interfaces change.
+func Macs(ctx context.Context, input []types.Value) (types.Value, error) {
+	ifs, err := net.Interfaces()
+	if err != nil {
+		return nil, err
+	}
+
+	values := []types.Value{}
+	for _, iface := range ifs {
+		// Check if the interface has the loopback flag set
+		if iface.Flags&net.FlagLoopback != 0 {
+			continue
+		}
+
+		mac := iface.HardwareAddr.String()
+
+		// Check if the MAC address is valid.
+		if len(mac) != len("00:00:00:00:00:00") {
+			continue // maybe something weird we want to ignore...
+		}
+
+		v := &types.StrValue{
+			V: mac,
+		}
+		values = append(values, v)
+	}
+
+	return &types.ListValue{
+		T: types.TypeListStr,
+		V: values,
+	}, nil
+}