/usr/share/gocode/src/github.com/docker/libnetwork/netutils/utils.go is in golang-github-docker-libnetwork-dev 0.8.0-dev.2+git20170202.599.45b4086-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | // Network utility functions.
package netutils
import (
"crypto/rand"
"encoding/hex"
"errors"
"fmt"
"io"
"net"
"strings"
"github.com/docker/libnetwork/types"
)
var (
// ErrNetworkOverlapsWithNameservers preformatted error
ErrNetworkOverlapsWithNameservers = errors.New("requested network overlaps with nameserver")
// ErrNetworkOverlaps preformatted error
ErrNetworkOverlaps = errors.New("requested network overlaps with existing network")
// ErrNoDefaultRoute preformatted error
ErrNoDefaultRoute = errors.New("no default route")
)
// CheckNameserverOverlaps checks whether the passed network overlaps with any of the nameservers
func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error {
if len(nameservers) > 0 {
for _, ns := range nameservers {
_, nsNetwork, err := net.ParseCIDR(ns)
if err != nil {
return err
}
if NetworkOverlaps(toCheck, nsNetwork) {
return ErrNetworkOverlapsWithNameservers
}
}
}
return nil
}
// NetworkOverlaps detects overlap between one IPNet and another
func NetworkOverlaps(netX *net.IPNet, netY *net.IPNet) bool {
return netX.Contains(netY.IP) || netY.Contains(netX.IP)
}
// NetworkRange calculates the first and last IP addresses in an IPNet
func NetworkRange(network *net.IPNet) (net.IP, net.IP) {
if network == nil {
return nil, nil
}
firstIP := network.IP.Mask(network.Mask)
lastIP := types.GetIPCopy(firstIP)
for i := 0; i < len(firstIP); i++ {
lastIP[i] = firstIP[i] | ^network.Mask[i]
}
if network.IP.To4() != nil {
firstIP = firstIP.To4()
lastIP = lastIP.To4()
}
return firstIP, lastIP
}
// GetIfaceAddr returns the first IPv4 address and slice of IPv6 addresses for the specified network interface
func GetIfaceAddr(name string) (net.Addr, []net.Addr, error) {
iface, err := net.InterfaceByName(name)
if err != nil {
return nil, nil, err
}
addrs, err := iface.Addrs()
if err != nil {
return nil, nil, err
}
var addrs4 []net.Addr
var addrs6 []net.Addr
for _, addr := range addrs {
ip := (addr.(*net.IPNet)).IP
if ip4 := ip.To4(); ip4 != nil {
addrs4 = append(addrs4, addr)
} else if ip6 := ip.To16(); len(ip6) == net.IPv6len {
addrs6 = append(addrs6, addr)
}
}
switch {
case len(addrs4) == 0:
return nil, nil, fmt.Errorf("Interface %v has no IPv4 addresses", name)
case len(addrs4) > 1:
fmt.Printf("Interface %v has more than 1 IPv4 address. Defaulting to using %v\n",
name, (addrs4[0].(*net.IPNet)).IP)
}
return addrs4[0], addrs6, nil
}
func genMAC(ip net.IP) net.HardwareAddr {
hw := make(net.HardwareAddr, 6)
// The first byte of the MAC address has to comply with these rules:
// 1. Unicast: Set the least-significant bit to 0.
// 2. Address is locally administered: Set the second-least-significant bit (U/L) to 1.
hw[0] = 0x02
// The first 24 bits of the MAC represent the Organizationally Unique Identifier (OUI).
// Since this address is locally administered, we can do whatever we want as long as
// it doesn't conflict with other addresses.
hw[1] = 0x42
// Fill the remaining 4 bytes based on the input
if ip == nil {
rand.Read(hw[2:])
} else {
copy(hw[2:], ip.To4())
}
return hw
}
// GenerateRandomMAC returns a new 6-byte(48-bit) hardware address (MAC)
func GenerateRandomMAC() net.HardwareAddr {
return genMAC(nil)
}
// GenerateMACFromIP returns a locally administered MAC address where the 4 least
// significant bytes are derived from the IPv4 address.
func GenerateMACFromIP(ip net.IP) net.HardwareAddr {
return genMAC(ip)
}
// GenerateRandomName returns a new name joined with a prefix. This size
// specified is used to truncate the randomly generated value
func GenerateRandomName(prefix string, size int) (string, error) {
id := make([]byte, 32)
if _, err := io.ReadFull(rand.Reader, id); err != nil {
return "", err
}
return prefix + hex.EncodeToString(id)[:size], nil
}
// ReverseIP accepts a V4 or V6 IP string in the canonical form and returns a reversed IP in
// the dotted decimal form . This is used to setup the IP to service name mapping in the optimal
// way for the DNS PTR queries.
func ReverseIP(IP string) string {
var reverseIP []string
if net.ParseIP(IP).To4() != nil {
reverseIP = strings.Split(IP, ".")
l := len(reverseIP)
for i, j := 0, l-1; i < l/2; i, j = i+1, j-1 {
reverseIP[i], reverseIP[j] = reverseIP[j], reverseIP[i]
}
} else {
reverseIP = strings.Split(IP, ":")
// Reversed IPv6 is represented in dotted decimal instead of the typical
// colon hex notation
for key := range reverseIP {
if len(reverseIP[key]) == 0 { // expand the compressed 0s
reverseIP[key] = strings.Repeat("0000", 8-strings.Count(IP, ":"))
} else if len(reverseIP[key]) < 4 { // 0-padding needed
reverseIP[key] = strings.Repeat("0", 4-len(reverseIP[key])) + reverseIP[key]
}
}
reverseIP = strings.Split(strings.Join(reverseIP, ""), "")
l := len(reverseIP)
for i, j := 0, l-1; i < l/2; i, j = i+1, j-1 {
reverseIP[i], reverseIP[j] = reverseIP[j], reverseIP[i]
}
}
return strings.Join(reverseIP, ".")
}
// ParseAlias parses and validates the specified string as an alias format (name:alias)
func ParseAlias(val string) (string, string, error) {
if val == "" {
return "", "", fmt.Errorf("empty string specified for alias")
}
arr := strings.Split(val, ":")
if len(arr) > 2 {
return "", "", fmt.Errorf("bad format for alias: %s", val)
}
if len(arr) == 1 {
return val, val, nil
}
return arr[0], arr[1], nil
}
// ValidateAlias validates that the specified string has a valid alias format (containerName:alias).
func ValidateAlias(val string) (string, error) {
if _, _, err := ParseAlias(val); err != nil {
return val, err
}
return val, nil
}
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