MacAddress Class Reference

IEEE 802 MAC (Ethernet hardware) address. More...

#include <macaddress.h>

Public Types
using	DataFormat = Array< uint8_t, 6 >
	Raw 6-byte storage format for a MAC address.

Public Member Functions
	MacAddress ()
	Default constructor. Creates a null (00:00:00:00:00:00) address.
	MacAddress (const DataFormat &bytes)
	Constructs from raw 6-byte data.
	MacAddress (uint8_t a, uint8_t b, uint8_t c, uint8_t d, uint8_t e, uint8_t f)
	Constructs from six individual octets.
bool	isNull () const
	Returns true if all bytes are zero.
bool	isBroadcast () const
	Returns true if this is the Ethernet broadcast address (ff:ff:ff:ff:ff:ff).
bool	isMulticast () const
	Returns true if this is a group (multicast) address.
bool	isGroupMulticast () const
	Returns true if this is a group multicast address but NOT broadcast.
bool	isIpv4Multicast () const
	Returns true if this is an IPv4 multicast MAC address.
bool	isIpv6Multicast () const
	Returns true if this is an IPv6 multicast MAC address.
bool	isUnicast () const
	Returns true if this is a unicast address.
bool	isLocallyAdministered () const
	Returns true if this is a locally-administered address.
const DataFormat &	data () const
	Returns a const reference to the raw 6-byte data.
const uint8_t *	raw () const
	Returns a pointer to the raw byte data.
uint8_t	octet (int index) const
	Returns a single octet of the address.
String	toString () const
	Returns a colon-separated hex string.
String	toString (char separator) const
	Returns a hex string with a custom separator.
bool	operator== (const MacAddress &other) const
	Returns true if both addresses are equal.
bool	operator!= (const MacAddress &other) const
	Returns true if the addresses are not equal.
bool	operator< (const MacAddress &other) const
	Less-than comparison for ordering (lexicographic).

Static Public Member Functions
static Result< MacAddress >	fromString (const String &str)
	Parses a MAC address from a string.
static MacAddress	broadcast ()
	Returns the Ethernet broadcast address (ff:ff:ff:ff:ff:ff).
static MacAddress	fromIpv4Multicast (const Ipv4Address &addr)
	Computes the multicast MAC address for an IPv4 multicast address.
static MacAddress	fromIpv6Multicast (const Ipv6Address &addr)
	Computes the multicast MAC address for an IPv6 multicast address.

Detailed Description

IEEE 802 MAC (Ethernet hardware) address.

Simple value type representing a 48-bit MAC address. Provides parsing, formatting, and classification (broadcast, multicast, locally-administered).

This class is purely computational and requires no platform-specific headers or system calls.

This class is not thread-safe. Concurrent access to a single instance requires external synchronization.

Example

auto [mac, err] = MacAddress::fromString("aa:bb:cc:dd:ee:ff");
if(mac.isMulticast()) { ... }
String str = mac.toString();  // "aa:bb:cc:dd:ee:ff"

Constructor & Destructor Documentation

MacAddress() [1/2]

MacAddress::MacAddress ( const DataFormat &  bytes )

inlineexplicit

Constructs from raw 6-byte data.

Parameters

bytes

The 6 bytes of the MAC address.

MacAddress() [2/2]

MacAddress::MacAddress ( uint8_t  a, uint8_t  b, uint8_t  c, uint8_t  d, uint8_t  e, uint8_t  f  )

inline

Constructs from six individual octets.

Parameters

a	First octet.
b	Second octet.
c	Third octet.
d	Fourth octet.
e	Fifth octet.
f	Sixth octet.

Member Function Documentation

data()

const DataFormat & MacAddress::data ( ) const

inline

Returns a const reference to the raw 6-byte data.

Returns

The underlying DataFormat array.

fromIpv4Multicast()

static MacAddress MacAddress::fromIpv4Multicast ( const Ipv4Address &  addr )

static

Computes the multicast MAC address for an IPv4 multicast address.

Maps an IPv4 multicast address (224.0.0.0/4) to its corresponding Ethernet multicast MAC address per IANA (RFC 1112). The mapping uses the OUI 01:00:5e and the low-order 23 bits of the IPv4 address, meaning that 32 different multicast IP addresses map to each MAC.

Parameters

addr	An IPv4 multicast address.

Returns

The corresponding MAC address, or a null MAC if addr is not multicast.

fromIpv6Multicast()

static MacAddress MacAddress::fromIpv6Multicast ( const Ipv6Address &  addr )

static

Computes the multicast MAC address for an IPv6 multicast address.

Maps an IPv6 multicast address (ff00::/8) to its corresponding Ethernet multicast MAC address per RFC 2464. The mapping uses the prefix 33:33 and the low-order 32 bits of the IPv6 address.

Parameters

addr	An IPv6 multicast address.

Returns

The corresponding MAC address, or a null MAC if addr is not multicast.

fromString()

static Result< MacAddress > MacAddress::fromString ( const String &  str )

static

Parses a MAC address from a string.

Accepts colon-separated ("aa:bb:cc:dd:ee:ff") or hyphen-separated ("aa-bb-cc-dd-ee-ff") hexadecimal notation. Case-insensitive.

Parameters

str	The string to parse.

Returns

A Result containing the parsed address and Error::Ok, or a null address and Error::Invalid on parse failure.

isBroadcast()

bool MacAddress::isBroadcast ( ) const

inline

Returns true if this is the Ethernet broadcast address (ff:ff:ff:ff:ff:ff).

This is the Layer 2 broadcast address used for both Ethernet broadcast frames and IP-level broadcast (255.255.255.255). Note that the broadcast address also has the group/multicast bit set, so isMulticast() returns true for the broadcast address.

isGroupMulticast()

bool MacAddress::isGroupMulticast ( ) const

inline

Returns true if this is a group multicast address but NOT broadcast.

Returns true when the I/G bit is set and the address is not ff:ff:ff:ff:ff:ff. This is the typical check for "is this a multicast destination" in the practical sense.

isIpv4Multicast()

bool MacAddress::isIpv4Multicast ( ) const

inline

Returns true if this is an IPv4 multicast MAC address.

IPv4 multicast maps to the IANA OUI 01:00:5e with the high bit of the fourth octet clear, giving the range 01:00:5e:00:00:00 through 01:00:5e:7f:ff:ff (RFC 1112).

isIpv6Multicast()

bool MacAddress::isIpv6Multicast ( ) const

inline

Returns true if this is an IPv6 multicast MAC address.

IPv6 multicast maps to the prefix 33:33 followed by the low-order 32 bits of the IPv6 address (RFC 2464).

isLocallyAdministered()

bool MacAddress::isLocallyAdministered ( ) const

inline

Returns true if this is a locally-administered address.

The second-least-significant bit of the first octet indicates local administration.

isMulticast()

bool MacAddress::isMulticast ( ) const

inline

Returns true if this is a group (multicast) address.

A MAC address is a group address when the least-significant bit of the first octet is set (IEEE 802 I/G bit). This includes both multicast addresses and the broadcast address (ff:ff:ff:ff:ff:ff). Use isBroadcast() to distinguish, or isGroupMulticast() to exclude broadcast.

isUnicast()

bool MacAddress::isUnicast ( ) const

inline

Returns true if this is a unicast address.

A unicast address has the I/G bit clear (not multicast, not broadcast).

octet()

uint8_t MacAddress::octet ( int  index ) const

inline

Returns a single octet of the address.

Parameters

index

Octet index (0-5).

Returns

The octet value, or 0 if index is out of range.

raw()

const uint8_t * MacAddress::raw ( ) const

inline

Returns a pointer to the raw byte data.

Returns

A pointer to the first byte.

toString() [1/2]

String MacAddress::toString

(

)

const

Returns a colon-separated hex string.

Returns

A String like "aa:bb:cc:dd:ee:ff" (lowercase).

toString() [2/2]

String MacAddress::toString

(

char

separator

)

const

Returns a hex string with a custom separator.

Parameters

separator

The character to place between octets.

Returns

A String like "aa-bb-cc-dd-ee-ff".

---

The documentation for this class was generated from the following file:

• include/promeki/network/macaddress.h