github.com/Psiphon-Labs/psiphon-tunnel-core@v2.0.28+incompatible/psiphon/common/tun/utils.go (about)

     1  /*
     2   * Copyright (c) 2017, Psiphon Inc.
     3   * All rights reserved.
     4   *
     5   * This program is free software: you can redistribute it and/or modify
     6   * it under the terms of the GNU General Public License as published by
     7   * the Free Software Foundation, either version 3 of the License, or
     8   * (at your option) any later version.
     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 tun
    21  
    22  import (
    23  	std_errors "errors"
    24  	"fmt"
    25  	"net"
    26  	"strconv"
    27  
    28  	"github.com/Psiphon-Labs/psiphon-tunnel-core/psiphon/common/errors"
    29  )
    30  
    31  var errUnsupported = std_errors.New("operation unsupported on this platform")
    32  
    33  func splitIPMask(IPAddressCIDR string) (string, string, error) {
    34  
    35  	IP, IPNet, err := net.ParseCIDR(IPAddressCIDR)
    36  	if err != nil {
    37  		return "", "", errors.Trace(err)
    38  	}
    39  
    40  	var netmask string
    41  	IPv4Mask := net.IP(IPNet.Mask).To4()
    42  	if IPv4Mask != nil {
    43  		netmask = fmt.Sprintf(
    44  			"%d.%d.%d.%d", IPv4Mask[0], IPv4Mask[1], IPv4Mask[2], IPv4Mask[3])
    45  	} else {
    46  		netmask = IPNet.Mask.String()
    47  	}
    48  
    49  	return IP.String(), netmask, nil
    50  }
    51  
    52  func splitIPPrefixLen(IPAddressCIDR string) (string, string, error) {
    53  
    54  	IP, IPNet, err := net.ParseCIDR(IPAddressCIDR)
    55  	if err != nil {
    56  		return "", "", errors.Trace(err)
    57  	}
    58  
    59  	prefixLen, _ := IPNet.Mask.Size()
    60  
    61  	return IP.String(), strconv.Itoa(prefixLen), nil
    62  }
    63  
    64  func getMTU(configMTU int) int {
    65  	if configMTU <= 0 {
    66  		return DEFAULT_MTU
    67  	} else if configMTU > 65536 {
    68  		return 65536
    69  	}
    70  	return configMTU
    71  }