Documentation
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Overview ¶
Package macaddr classifies an IEEE 802 MAC address (EUI-48) from its two administration bits — the I/G bit (individual vs group/multicast) and the U/L bit (universally vs locally administered). The U/L bit is the standard signal that an address is locally administered, which on a unicast address is the hallmark of a randomized / privacy MAC (modern iOS, Android, Windows and Linux randomize the client MAC, setting this bit). It is the offline analysis complement to the WiFi/BLE scan tooling, whose results are lists of MACs.
Wrap-vs-native judgement ¶
Native. The classification is two bit tests on the first octet plus an all-ones broadcast check — the IEEE 802 address-format rules, fixed and unambiguous. There is nothing to wrap.
Verifiable / no confidently-wrong output ¶
The I/G and U/L bits have exact, universally-agreed definitions, so the multicast / locally-administered / broadcast determinations are facts, not guesses. The "randomized MAC" reading is framed as an observation (a locally-administered unicast address is *commonly* a randomized/privacy MAC), not a verdict — a device can be locally administered for other reasons. The OUI (first three octets) is surfaced raw and only when the address is universally administered (a locally-administered address has no meaningful OUI); the full IEEE OUI-to-vendor registry is large and not embedded here, so a vendor name is not guessed at this layer.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func MACToEUI64IID ¶ added in v0.424.0
MACToEUI64IID builds the Modified EUI-64 interface identifier (8 bytes) for a MAC — the forward transform RecoverMAC inverts. Exposed so callers (and the round-trip tests) can synthesise a SLAAC interface identifier from a MAC.
Types ¶
type EUI64Result ¶ added in v0.424.0
type EUI64Result struct {
IPv6 string `json:"ipv6"`
InterfaceID string `json:"interface_id"` // low 64 bits, hex
EUI64Derived bool `json:"eui64_derived"`
RecoveredMAC string `json:"recovered_mac,omitempty"`
Notes []string `json:"notes,omitempty"`
}
EUI64Result is the recovery of a MAC address from an IPv6 interface identifier (the low 64 bits of the address).
func RecoverMAC ¶ added in v0.424.0
func RecoverMAC(ipv6 string) (*EUI64Result, error)
RecoverMAC inspects an IPv6 address's interface identifier (low 64 bits) and, when it is a Modified EUI-64 — recognised by the FF:FE marker in the middle — recovers the embedded MAC by removing the FF:FE and flipping the U/L bit back. This deanonymises a host whose SLAAC address was derived from its MAC. A privacy-extension / RFC 7217 stable-private / random IID does not carry the marker (and matches it only ~1 in 65536 by chance), so the result is framed as an observation, not a certainty.
type Result ¶
type Result struct {
MAC string `json:"mac"` // normalised AA:BB:CC:DD:EE:FF
Unicast bool `json:"unicast"`
Multicast bool `json:"multicast"`
Broadcast bool `json:"broadcast"`
LocallyAdministered bool `json:"locally_administered"`
UniversallyAdministered bool `json:"universally_administered"`
OUI string `json:"oui,omitempty"` // first 3 octets, only when universally administered
RandomizedLikely bool `json:"randomized_likely"`
Notes []string `json:"notes,omitempty"`
}
Result is the structural classification of a MAC address.
Source Files