github.com/rigado/snapd@v2.42.5-go-mod+incompatible/overlord/configstate/configcore/network.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2018 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package configcore
    21  
    22  import (
    23  	"bytes"
    24  	"fmt"
    25  	"os/exec"
    26  	"path/filepath"
    27  
    28  	"github.com/snapcore/snapd/dirs"
    29  	"github.com/snapcore/snapd/osutil"
    30  	"github.com/snapcore/snapd/overlord/configstate/config"
    31  )
    32  
    33  func init() {
    34  	// add supported configuration of this module
    35  	supportedConfigurations["core.network.disable-ipv6"] = true
    36  }
    37  
    38  func validateNetworkSettings(tr config.Conf) error {
    39  	return validateBoolFlag(tr, "network.disable-ipv6")
    40  }
    41  
    42  func handleNetworkConfiguration(tr config.Conf) error {
    43  	dir := filepath.Join(dirs.GlobalRootDir, "/etc/sysctl.d")
    44  	name := "10-snapd-network.conf"
    45  	content := bytes.NewBuffer(nil)
    46  
    47  	output, err := coreCfg(tr, "network.disable-ipv6")
    48  	if err != nil {
    49  		return nil
    50  	}
    51  
    52  	var sysctl string
    53  	switch output {
    54  	case "true":
    55  		sysctl = "net.ipv6.conf.all.disable_ipv6=1"
    56  		content.WriteString(sysctl + "\n")
    57  	case "false", "":
    58  		// Store the sysctl for the code below but don't write it to
    59  		// content so that the file setting this option gets removed.
    60  		sysctl = "net.ipv6.conf.all.disable_ipv6=0"
    61  	default:
    62  		return fmt.Errorf("unsupported disable-ipv6 option: %q", output)
    63  	}
    64  	dirContent := map[string]*osutil.FileState{}
    65  	if content.Len() > 0 {
    66  		dirContent[name] = &osutil.FileState{
    67  			Content: content.Bytes(),
    68  			Mode:    0644,
    69  		}
    70  	}
    71  
    72  	// write the new config
    73  	glob := name
    74  	changed, removed, err := osutil.EnsureDirState(dir, glob, dirContent)
    75  	if err != nil {
    76  		return err
    77  	}
    78  
    79  	// load the new config into the kernel
    80  	if len(changed) > 0 || len(removed) > 0 {
    81  		output, err := exec.Command("sysctl", "-w", sysctl).CombinedOutput()
    82  		if err != nil {
    83  			return osutil.OutputErr(output, err)
    84  		}
    85  	}
    86  
    87  	return nil
    88  }