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addr.go
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addr.go
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package nom
import (
"bytes"
"encoding/gob"
"fmt"
)
// MACAddr represents a MAC address.
type MACAddr [6]byte
var (
MaskNoneMAC MACAddr = [6]byte{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
BroadcastMAC MACAddr = [6]byte{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
CDPMulticastMAC MACAddr = [6]byte{0x01, 0x00, 0x0C, 0xCC, 0xCC, 0xCC}
CiscoSTPMulticastMAC MACAddr = [6]byte{0x01, 0x00, 0x0C, 0xCC, 0xCC, 0xCD}
IEEE802MulticastPrefix MACAddr = [6]byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x00}
IPv4MulticastPrefix MACAddr = [6]byte{0x01, 0x00, 0x5E, 0x00, 0x00, 0x00}
IPv6MulticastPrefix MACAddr = [6]byte{0x33, 0x33, 0x00, 0x00, 0x00, 0x00}
LLDPMulticastMACs []MACAddr = []MACAddr{
[6]byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x0E},
[6]byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x0C},
[6]byte{0x01, 0x80, 0xC2, 0x00, 0x00, 0x00},
}
MaskNoneIPV4 IPv4Addr = [4]byte{0xFF, 0xFF, 0xFF, 0xFF}
MaskNoneIPV6 IPv6Addr = [16]byte{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
)
func (m MACAddr) String() string {
return fmt.Sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
m[0], m[1], m[2], m[3], m[4], m[5])
}
// Key returns an string represtation of the MAC address suitable to store in
// dictionaries. It is more efficient compared to MACAddr.String().
func (m MACAddr) Key() string {
return string(m[:])
}
// IsBroadcast returns whether the MAC address is a broadcast address.
func (m MACAddr) IsBroadcast() bool {
return m == BroadcastMAC
}
// IsMulticast returns whether the MAC address is a multicast address.
func (m MACAddr) IsMulticast() bool {
return m == CDPMulticastMAC || m == CiscoSTPMulticastMAC ||
m.hasPrefix(IEEE802MulticastPrefix, 3) ||
m.hasPrefix(IPv4MulticastPrefix, 3) ||
m.hasPrefix(IPv6MulticastPrefix, 2)
}
// IsLLDP returns whether the mac address is a multicast address used for LLDP.
func (m MACAddr) IsLLDP() bool {
for _, lm := range LLDPMulticastMACs {
if m == lm {
return true
}
}
return false
}
func (m MACAddr) hasPrefix(p MACAddr, l int) bool {
for i := 0; i < l; i++ {
if p[i] != m[i] {
return false
}
}
return true
}
func (m MACAddr) Mask(mask MACAddr) MACAddr {
masked := m
for i := range mask {
masked[i] &= mask[i]
}
return masked
}
func (m MACAddr) Less(thatm MACAddr) bool {
for i := range thatm {
switch {
case m[i] < thatm[i]:
return true
case m[i] > thatm[i]:
return false
}
}
return false
}
// MaskedMACAddr is a MAC address that is wildcarded with a mask.
type MaskedMACAddr struct {
Addr MACAddr // The MAC address.
Mask MACAddr // The mask of the MAC address.
}
// Match returns whether the masked mac address matches mac.
func (mm MaskedMACAddr) Match(mac MACAddr) bool {
return mm.Mask.Mask(mm.Addr) == mm.Mask.Mask(mac)
}
// Subsumes returns whether this mask address includes all the addresses matched
// by thatmm.
func (mm MaskedMACAddr) Subsumes(thatmm MaskedMACAddr) bool {
if thatmm.Mask.Less(mm.Mask) {
return false
}
return mm.Match(thatmm.Addr.Mask(thatmm.Mask))
}
// IPv4Addr represents an IP version 4 address in big endian byte order.
// For example, 127.0.0.1 is represented as IPv4Addr{127, 0, 0, 1}.
type IPv4Addr [4]byte
// Uint converts the IP version 4 address into a 32-bit integer in little
// endian byte order.
func (ip IPv4Addr) Uint() uint32 {
return uint32(ip[0])<<24 | uint32(ip[1])<<16 | uint32(ip[2])<<8 |
uint32(ip[3])
}
// FromUint loads the ip address from addr.
func (ip *IPv4Addr) FromUint(addr uint32) {
for i := 0; i < 4; i++ {
ip[i] = byte((addr >> uint(8*(3-i))) & 0xFF)
}
}
// PopCount returns the number of ones in the IP address. For example, it
// returns 16 for IPv4Addr{255, 255, 0, 0}.
func (ip IPv4Addr) PopCount() uint32 {
v := ip.Uint()
v -= (v >> 1) & 0x55555555
v = ((v >> 2) & 0x33333333) + v&0x33333333
v = ((v >> 4) + v) & 0x0F0F0F0F
v = ((v >> 8) + v) & 0x00FF00FF
return ((v >> 16) + v) & 0x0000FFFF
}
// Mask masked the IP address with mask.
func (ip IPv4Addr) Mask(mask IPv4Addr) IPv4Addr {
masked := ip
for i := range masked {
masked[i] &= mask[i]
}
return masked
}
// Less returns whether ip is less than thatip.
func (ip IPv4Addr) Less(thatip IPv4Addr) bool {
for i := range ip {
switch {
case ip[i] < thatip[i]:
return true
case ip[i] > thatip[i]:
return false
}
}
return false
}
// AsCIDRMask returns the CIDR prefix number based on this address.
// For example, it returns 24 for 255.255.255.0.
func (ip IPv4Addr) AsCIDRMask() int {
m := 0
for i := len(ip) - 1; i >= 0; i-- {
for j := uint(0); j < 8; j++ {
if (ip[i]>>j)&0x1 != 0 {
return 32 - m
}
m++
}
}
return 0
}
func (ip IPv4Addr) String() string {
return fmt.Sprintf("%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3])
}
// CIDRToMaskedIPv4 converts a CIDR-style IP address into a NOM masked IP
// address. For example, if addr is 0x7F000001 and mask is 24, this function
// returns {IPv4Addr{127, 0, 0, 1}, IPv4Addr{255, 255, 255, 0}}.
func CIDRToMaskedIPv4(addr uint32, mask uint) MaskedIPv4Addr {
var maskedip MaskedIPv4Addr
maskedip.Addr.FromUint(addr)
maskedip.Mask.FromUint(uint32(((1 << mask) - 1) << (32 - mask)))
return maskedip
}
// MaskedIPv4Addr represents a masked IP address (ie, an IPv4 prefix)
type MaskedIPv4Addr struct {
Addr IPv4Addr
Mask IPv4Addr
}
// Match returns whether the masked IP address matches ip.
func (mi MaskedIPv4Addr) Match(ip IPv4Addr) bool {
return mi.Addr.Mask(mi.Mask) == ip.Mask(mi.Mask)
}
func (mi MaskedIPv4Addr) Subsumes(thatmi MaskedIPv4Addr) bool {
if thatmi.Mask.Less(mi.Mask) {
return false
}
return mi.Addr.Mask(mi.Mask) == thatmi.Addr.Mask(mi.Mask)
}
func (mi MaskedIPv4Addr) String() string {
return fmt.Sprintf("%v/%d", mi.Addr, mi.Mask.AsCIDRMask())
}
// IPv6Addr represents an IP version 6 address in big-endian byte order.
type IPv6Addr [16]byte
// Mask masked the IP address with mask.
func (ip IPv6Addr) Mask(mask IPv6Addr) IPv6Addr {
masked := ip
for i := range masked {
masked[i] &= mask[i]
}
return masked
}
// Less returns whether ip is less than thatip.
func (ip IPv6Addr) Less(thatip IPv6Addr) bool {
for i := range ip {
switch {
case ip[i] < thatip[i]:
return true
case ip[i] > thatip[i]:
return false
}
}
return false
}
func (ip IPv6Addr) String() string {
var buf bytes.Buffer
zeros := 0
for i := 0; i < 16; i += 2 {
if ip[i] == 0 && ip[i+1] == 0 {
zeros++
if zeros == 2 {
if zeros == i {
buf.WriteString("::")
} else {
buf.WriteString(":")
}
}
continue
}
if zeros == 1 {
buf.WriteString("0:")
}
buf.WriteString(fmt.Sprintf("%x", int(ip[i])<<8|int(ip[i+1])))
if i != 14 {
buf.WriteString(":")
}
zeros = 0
}
return buf.String()
}
// AsCIDRMask returns the CIDR prefix number based on this address.
func (ip IPv6Addr) AsCIDRMask() int {
m := 0
for i := len(ip) - 1; i >= 0; i-- {
for j := uint(0); j < 8; j++ {
if (ip[i]>>j)&0x1 != 0 {
return 128 - m
}
m++
}
}
return 0
}
// MaskedIPv6Addr represents a masked IPv6 address.
type MaskedIPv6Addr struct {
Addr IPv6Addr
Mask IPv6Addr
}
// Match returns whether the masked IP address matches ip.
func (mi MaskedIPv6Addr) Match(ip IPv6Addr) bool {
return mi.Addr.Mask(mi.Mask) == ip.Mask(mi.Mask)
}
func (mi MaskedIPv6Addr) Subsumes(thatmi MaskedIPv6Addr) bool {
if thatmi.Mask.Less(mi.Mask) {
return false
}
return mi.Addr.Mask(mi.Mask) == thatmi.Addr.Mask(mi.Mask)
}
func (mi MaskedIPv6Addr) String() string {
return fmt.Sprintf("%v/%d", mi.Addr, mi.Mask.AsCIDRMask())
}
func init() {
gob.Register(IPv4Addr{})
gob.Register(IPv6Addr{})
gob.Register(MACAddr{})
gob.Register(MaskedIPv4Addr{})
gob.Register(MaskedIPv6Addr{})
gob.Register(MaskedMACAddr{})
}